Showing papers in "Spine in 2010"

Adult spinal deformity-postoperative standing imbalance: how much can you tolerate? An overview of key parameters in assessing alignment and planning corrective surgery.

Abstract: Study design Current concepts review. Objective Outline the basic principles in the evaluation and treatment of adult spinal deformity patients with a focus on goals to achieve during surgical realignment surgery. Summary of background data Proper global alignment of the spine is critical in maintaining standing posture and balance in an efficient and pain-free manner. Outcomes data demonstrate the clinical effect of spinopelvic malalignment and form a basis for realignment strategies. Methods Correlation between certain radiographic parameters and patient self-reported pain and disability has been established. Using normative values for several important spinopelvic parameters (including sagittal vertical axis, pelvic tilt, and lumbar lordosis), spinopelvic radiographic realignment objectives were identified as a tool for clinical application. Because of the complex relationship between the spine and the pelvis in maintaining posture and the wide range of "normal" values for the associated parameters, a focus on global alignment, with proportionality of individual parameters to each other, was pursued to provide clinical relevance to planning realignment for deformity across a range of clinical cases. Conclusion Good clinical outcome requires achieving proper spinopelvic alignment in the treatment of adult spinal deformity. Although variations in pelvic morphology exist, a framework has been established to determine ideal values for regional and global parameter in an individualized patient approach. When planning realignment surgery for adult spinal deformity, restoring low sagittal vertical axis and pelvic tilt values are critical goals, and should be combined with proportional lumbar lordosis to pelvic incidence.

A novel classification system for spinal instability in neoplastic disease: an evidence-based approach and expert consensus from the Spine Oncology Study Group.

Abstract: Study design Systematic review and modified Delphi technique. Objective To use an evidence-based medicine process using the best available literature and expert opinion consensus to develop a comprehensive classification system to diagnose neoplastic spinal instability. Summary of background data Spinal instability is poorly defined in the literature and presently there is a lack of guidelines available to aid in defining the degree of spinal instability in the setting of neoplastic spinal disease. The concept of spinal instability remains important in the clinical decision-making process for patients with spine tumors. Methods We have integrated the evidence provided by systematic reviews through a modified Delphi technique to generate a consensus of best evidence and expert opinion to develop a classification system to define neoplastic spinal instability. Results A comprehensive classification system based on patient symptoms and radiographic criteria of the spine was developed to aid in predicting spine stability of neoplastic lesions. The classification system includes global spinal location of the tumor, type and presence of pain, bone lesion quality, spinal alignment, extent of vertebral body collapse, and posterolateral spinal element involvement. Qualitative scores were assigned based on relative importance of particular factors gleaned from the literature and refined by expert consensus. Conclusion The Spine Instability Neoplastic Score is a comprehensive classification system with content validity that can guide clinicians in identifying when patients with neoplastic disease of the spine may benefit from surgical consultation. It can also aid surgeons in assessing the key components of spinal instability due to neoplasia and may become a prognostic tool for surgical decision-making when put in context with other key elements such as neurologic symptoms, extent of disease, prognosis, patient health factors, oncologic subtype, and radiosensitivity of the tumor.

Surgical versus nonoperative treatment for lumbar spinal stenosis four-year results of the Spine Patient Outcomes Research Trial.

Abstract: Study design Randomized trial and concurrent observational cohort study. Objective To compare 4 year outcomes of surgery to nonoperative care for spinal stenosis. Summary of background data Surgery for spinal stenosis has been shown to be more effective compared to nonoperative treatment over 2 years, but longer-term data have not been analyzed. Methods Surgical candidates from 13 centers in 11 US states with at least 12 weeks of symptoms and confirmatory imaging were enrolled in a randomized cohort (RC) or observational cohort (OC). Treatment was standard decompressive laminectomy or standard nonoperative care. Primary outcomes were SF-36 bodily pain (BP) and physical function scales and the modified Oswestry Disability index assessed at 6 weeks, 3 months, 6 months, and yearly up to 4 years. Results A total of 289 patients enrolled in the RC and 365 patients enrolled in the OC. An as-treated analysis combining the RC and OC and adjusting for potential confounders found that the clinically significant advantages for surgery previously reported were maintained through 4 years, with treatment effects (defined as mean change in surgery group minus mean change in nonoperative group) for bodily pain 12.6 (95% confidence interval [CI], 8.5-16.7); physical function 8.6 (95% CI, 4.6-12.6); and Oswestry Disability index -9.4 (95% CI, -12.6 to -6.2). Early advantages for surgical treatment for secondary measures such as bothersomeness, satisfaction with symptoms, and self-rated progress were also maintained. Conclusion Patients with symptomatic spinal stenosis treated surgically compared to those treated nonoperatively maintain substantially greater improvement in pain and function through 4 years.

Qualitative grading of severity of lumbar spinal stenosis based on the morphology of the dural sac on magnetic resonance images.

Abstract: Study design Retrospective radiologic study on a prospective patient cohort. Objective To devise a qualitative grading of lumbar spinal stenosis (LSS), study its reliability and clinical relevance. Summary of background data Radiologic stenosis is assessed commonly by measuring dural sac cross-sectional area (DSCA). Great variation is observed though in surfaces recorded between symptomatic and asymptomatic individuals. Methods We describe a 7-grade classification based on the morphology of the dural sac as observed on T2 axial magnetic resonance images based on the rootlet/cerebrospinal fluid ratio. Grades A and B show cerebrospinal fluid presence while grades C and D show none at all. The grading was applied to magnetic resonance images of 95 subjects divided in 3 groups as follows: 37 symptomatic LSS surgically treated patients; 31 symptomatic LSS conservatively treated patients (average follow-up, 2.5 and 3.1 years); and 27 low back pain (LBP) sufferers. DSCA was also digitally measured. We studied intra- and interobserver reliability, distribution of grades, relation between morphologic grading and DSCA, as well relation between grades, DSCA, and Oswestry Disability Index. Results Average intra- and interobserver agreement was substantial and moderate, respectively (k = 0.65 and 0.44), whereas they were substantial for physicians working in the study originating unit. Surgical patients had the smallest DSCA. A larger proportion of C and D grades was observed in the surgical group. Surface measurements resulted in overdiagnosis of stenosis in 35 patients and under diagnosis in 12. No relation could be found between stenosis grade or DSCA and baseline Oswestry Disability Index or surgical result. C and D grade patients were more likely to fail conservative treatment, whereas grades A and B were less likely to warrant surgery. Conclusion The grading defines stenosis in different subjects than surface measurements alone. Since it mainly considers impingement of neural tissue it might be a more appropriate clinical and research tool as well as carrying a prognostic value.

Complications of pedicle screw fixation in scoliosis surgery: a systematic review.

Abstract: Study design Systematic review. Objective To review the published literature on the use of pedicle screws in pediatric spinal deformity to quantify the risks and complications associated with pedicle screw instrumentation, particularly in the thoracic spine. Summary of background data The use of pedicle screws in adolescent scoliosis surgery is common. Although many reports have been published regarding the use of pedicle screws in pediatric patients, there has been no systematic review on the risks of complications. Methods PubMed, Ovid Medline, and Cochrane databases were searched for studies reporting the use of thoracic pedicle screws in pediatric deformity. We excluded articles dealing with neuromuscular scoliosis or bone dysplasia to focus mostly on adolescent thoracic idiopathic scoliosis and the likes. We then searched for cases reports dealing with thoracic pedicle screws complications. Results This systematic review retrieved 21 studies with a total of 4570 pedicle screws in 1666 patients. The mean age of the patients was 17.6 years; 812 patients were women and 252 were men, and 5 studies did not identify sex. Overall, 518 (4.2%) screws were reported as malpositioned. However, in studies in which postoperative computed tomography scans were done systematically, the rate of screw malpositioning was as high as 15.7%. The reported percentage of patients with screw malpositioned is around 11%. Eleven patients underwent revision surgery for instrumentation malposition. Other complications reported include loss of curve correction, intraoperative pedicle fracture or loosening, dural laceration, deep infection, pseudarthrosis, and transient neurologic injury. There were no major vascular complications reported in these 21 studies. We could identify 9 case report articles dealing with complications of pedicle screws. Such complications were mostly either vascular (10 cases) or neurologic (4 cases), without any irreversible complications. Conclusion Malposition is the most commonly reported complication of thoracic pedicle screw placement, at a rate of 15.7% per screw inserted with postoperative computed tomography scans. The use of pedicle screws in the thoracic spine for the treatment of pediatric deformity has been reported to be safe despite the high rate of patients with malpositioned screws (11%). Major complications, such as neurologic or vascular injury, were almost never reported in this literature review of case series. Cases reports on the other hand have started to identify such complications.

The association between lumbar disc degeneration and low back pain: the influence of age, gender, and individual radiographic features.

Abstract: Study design Cross-sectional open population based study (nested in a prospective cohort study) Objective To explore the association of the different individual radiographic features, including osteophytes and disc space narrowing, with self-reported low back pain (LBP) Different definitions of lumbar disc degeneration with self-reported LBP and disability were considered in a large open population sample Furthermore, in order to disentangle the discrepancies in reported strength of the associations, we characterized the frequency of the different individual radiographic features of lumbar disc degeneration and definitions of lumbar disc degeneration, as well as their association with LBP status, by age, gender, and vertebral level Summary of background data Currently within the literature, there have been no studies that have explored different definitions of lumbar disc degeneration and their association with LBP within one study sample Methods The intervertebral disc spaces (L1/2 to L5-S1) were evaluated for the presence and severity of anterior osteophytes and disc space narrowing using a semiquantitative score (grade 0-3) Logistic regression was used to determine the association between these individual radiographic features of lumbar disc degeneration and different definitions of lumbar disc degeneration for LBP Results Lumbar radiographs were scored for 1204 men, and 1615 women Osteophytes were the most frequent radiographic feature observed, with men having the greatest frequency Disc space narrowing was more frequent in women than men Both radiographic features increased in frequency with ageDisc space narrowing appeared more strongly associated with LBP than osteophytes, especially in men (odds ratio [OR] = 19; 95% confidence interval [CI]: 14-28) Disc space narrowing at 2 or more levels appeared more strongly associated with LBP than disc space narrowing at only 1 level (OR = 24; 95% CI: 16-34) After excluding level L5-S1, the strength of almost all associations increased Conclusion We are the first to report different possible lumbar disc degeneration definitions and their associations with LBP Disc space narrowing at 2 or more levels appeared more strongly associated with LBP than other radiographic features, especially after excluding level L5-S1

A radiographic assessment of the ability of the extreme lateral interbody fusion procedure to indirectly decompress the neural elements.

Abstract: Study Design. Prospective nonrandomized clinical study on the decompressive effect of the extreme lateral interbody fusion (XLIF) procedure. Objective. This study evaluates the results of interbody distraction from a lateral retroperitoneal approach for the treatment of lumbar degenerative conditions inclusive of central and/or lateral stenosis. Summary of Background Data. Traditional treatment for symptomatic lumbar stenosis has been by direct posterior decompression (i.e., removal of ligamentum flavum, laminotomy/laminectomy, facetectomy, as needed). Stenotic symptoms may also be alleviated indirectly, through correction of intervertebral and foraminal height and correction of spinal alignment. Anterior-only spinal procedures rely on this indirect decompression when used in patients with radicular symptoms. Methods. Consecutive patients presenting with degenerative conditions that included concomitant lumbar stenosis were consented and treated via stand-alone XLIF. Pre- and postoperative radiographic measurements were made from plain lateral radiographs and sagittal and axial magnetic resonance imaging views by an independent radiologist using medical imaging software. Measurements included disc height, foraminal height, foraminal area, and canal diameter. Results. In all, 7 male and 14 female patients (mean age, 67.6 years; range, 40-83) underwent XLIF at 43 lumbar levels in an average operative time of 47 minutes and with an average 23 mL estimated blood loss per level. There were no intraoperative complications. Mean hospital stay was 29.5 hours. Transient postoperative psoas weakness occurred in 3 (14.3%) of the cases. Substantial dimensional improvement was evidenced in all radiographic parameters, with increases of 41.9% in average disc height, 13.5% in foraminal height, 24.7% in foraminal area, and 33.1% in central canal diameter. Two patients (9.5%) required a second procedure for additional posterior decompression and/or instrumentation. Conclusion. The XLIF procedure provides the necessary decompression for the treatment of central and/or-lateral stenosis in a minimally disruptive way, avoiding, in most cases, the need for the direct resection of posterior elements and associated morbidities. Indirect decompression may be limited in cases of congenital stenosis and/or locked facets. Its effect may also be reduced by postoperative subsidence and/or loss of correction.

A prospective, nonrandomized, multicenter evaluation of extreme lateral interbody fusion for the treatment of adult degenerative scoliosis: perioperative outcomes and complications

Abstract: Study design Prospective multicenter nonrandomized institutional review board-approved observational study of clinical and radiographic outcomes of the extreme lateral interbody fusion (XLIF) procedure in adult scoliosis. Objective Perioperative measures from this longitudinal study were compiled to identify the short-term results and complications of the procedure. Summary of background data The surgical treatment of adult scoliosis presents a treatment challenge. Neural decompression with combined anterior/posterior instrumented fusion is often performed. These procedures have been reported to carry a high risk of complication, particularly in the elderly patient population. Over the past decade, less invasive surgical approaches to neural decompression and fusion have been popularized and have recently been applied in the treatment of degenerative scoliosis. To date, there has been little published data evaluating these treatment approaches. Methods A total of 107 patients who underwent the XLIF procedure with or without supplemental posterior fusion for the treatment of degenerative scoliosis were prospectively studied. Intraoperative data collection included surgical procedural details, operative time, estimated blood loss, and surgical complications. Postoperative complications, length of hospital stay, and neurologic status were recorded. For this report, perioperative data (inclusive of outcomes through the 6-week postoperative clinic visit) were evaluated. Results In all, 107 patients (mean age, 68 years; range, 45-87) were treated with XLIF; 28% had at least 1 comorbidity. A mean of 4.4 levels (range, 1-9) were treated per patient. Supplemental pedicle screw fixation was used in 75.7% of patients, 5.6% had lateral fixation, and 18.7% had stand-alone XLIF. Mean operative time and blood loss were 178 minutes (58 minutes/level) and 50 to 100 mL. Mean hospital stay was 2.9 days (unstaged), 8.1 day (staged, 16.5%), 3.8 days overall. Five patients (4.7%) received a transfusion, 3 (2.8%) required intensive care unit admission, and 1 (0.9%) required rehabilitation services. Major complications occurred in 13 patients (12.1%): 2 (1.9%) medical, 12 (11.2%) surgical. Of procedures that involved only less invasive techniques (XLIF stand-alone or with percutaneous instrumentation), 9.0% had one or more major complications. In those with supplemental open posterior instrumentation, 20.7% had one or more major complication. Early reoperations (3) (all for deep wound infections) were associated with open posterior instrumentation procedures. Conclusion The morbidity in adult scoliosis surgery is minimized with less invasive techniques. The rate of major complications in this study (12.1%) compares favorably to that reported from other studies of surgery for degenerative deformity.

Diagnostic imaging of spinal deformities: reducing patients radiation dose with a new slot-scanning X-ray imager.

Abstract: Study Design. Clinical trial comparing image quality and entrance dose between Biospace EOS system, a new slot-scanning radiographic device, and a Fuji FCR 7501S computed radiography (CR) system for 50 patients followed for spinal deformities. Objective. Based on their physical properties, slot-scanners show the potential to produce image quality comparable to CR systems using less radiation. This article validates this assertion by comparing a new slot-scanner to a CR system through a wide-ranging evaluation of dose and image quality for scoliosis examinations. Summary of Background Data. For each patient included in this study, lateral and posteroanterior images were acquired with both systems. For each system, entrance dose was measured for different anatomic locations. Methods. Dose and image quality being directly related, comparable images were obtained using the same radiograph tube voltage on both systems while tube currents were selected to match signal-to-noise ratios on a phantom. Different techniques were defined with respect to patient's thickness about the iliac crests. Given dose amplitudes expected for scoliosis examinations, optically stimulated luminescence dosimeters were chosen as optimal sensors. Two radiologists and 2 orthopedists evaluated the images in a randomized order using a questionnaire targeting anatomic landmarks. Visibility of the structures was rated on a 4 level scale. Image quality assessment was analyzed using a Wilcoxon signed-rank tests. Results. Average skin dose was reduced from 6 to 9 times in the thoracoabdominal region when using the slot-scanner instead of CR. Moreover, image quality was significantly better with EOS for all structures in the frontal view (P < 0.006) and lateral view (P < 0.04), except for lumbar spinous processes, better seen on the CR (P < 0.003). Conclusion. We established that the EOS system offers overall enhanced image quality while reducing drastically the entrance dose for the patient.

Clinical acceptance and accuracy assessment of spinal implants guided with SpineAssist surgical robot: retrospective study.

Abstract: Study Design. Retrospective, multicenter study of robotically-guided spinal implant insertions. Clinical acceptance of the implants was assessed by intraoperative radiograph, and when available, postoperative computed tomography (CT) scans were used to determine placement accuracy. Objective. To verify the clinical acceptance and accuracy of robotically-guided spinal implants and compare to those of unguided free-hand procedures. Summary of Background Data. SpineAssist surgical robot has been used to guide implants and guide-wires to predefined locations in the spine. SpineAssist which, to the best of the authors' knowledge, is currently the sole robot providing surgical assistance in positioning tools in the spine, guided over 840 cases in 14 hospitals, between June 2005 and June 2009. Methods. Clinical acceptance of 3271 pedicle screws and guide-wires inserted in 635 reported cases was assessed by intraoperative fluoroscopy, where placement accuracy of 646 pedicle screws inserted in 139 patients was measured using postoperative CT scans. Results. Screw placements were found to be clinically acceptable in 98% of the cases when intraoperatively assessed by fluoroscopic images. Measurements derived from postoperative CT scans demonstrated that 98.3% of the screws fell within the safe zone, where 89.3% were completely within the pedicle and 9% breached the pedicle by up to 2 mm. The remaining 1.4% of the screws breached between 2 and 4 mm, while only 2 screws (0.3%) deviated by more than 4 mm from the pedicle wall. Neurologic deficits were observed in 4 cases yet, following revisions, no permanent nerve damage was encountered, in contrast to the 0.6% to 5% of neurologic damage reported in the literature. Conclusion. SpineAssist offers enhanced performance in spinal surgery when compared to free-hand surgeries, by increasing placement accuracy and reducing neurologic risks. In addition, 49% of the cases reported herein used a percutaneous approach, highlighting the contribution of SpineAssist in procedures without anatomic landmarks.

Spine fractures in patients with ankylosing spinal disorders.

Abstract: STUDY DESIGN Retrospective review. OBJECTIVE To describe the spine fracture characteristics, current treatments, and their results in patients with ankylosing spinal disorders (ASD), such as ankylosing spondylitis (AS) and diffuse idiopathic skeletal hyperostosis (DISH), with the hypothesis that complication and mortality rates are high. SUMMARY OF BACKGROUND DATA Spine fractures in patients with ASD are unique and have only been described in relatively small case series. METHODS Retrospective review of a large consecutive series of patients with spine fractures and ASD over a 7-year period. Complications were stratified according to parameters such as type and number of comorbidities, patient age, and mechanism of injury. Predictors of mortality were analyzed by linear regression. Similarities between patients with AS and DISH were evaluated by chi analysis. RESULTS Of the 122 spine fractures in 112 consecutive patients with ASD, the majority were transdiscal extension injuries, most commonly affecting C6-C7. Eighty-one percent of the patients had at least 1 major medical comorbidity. Spinal cord injury was present in 58% of the patients, 34% of whom improved by at least 1 American Spinal Injury Association grade. Nineteen percent of patients had delayed diagnosis of their spine fracture, 81% of whom had resulting neurologic compromise. Surgery was performed on 67% of patients, consisting primarily of multilevel posterior instrumentation 3 levels above and below the injury. Eighty-four percent of all patients had at least 1 complication. Mortality was 32% and correlated with age > or =70 (P < 0.0001), number of comorbidities (P < 0.0001), and low-energy mechanism of injury (P = 0.009). AS patients were younger (P = 0.03) and had a higher risk of delayed fracture diagnosis (P = 0.012), but were otherwise similar to DISH patients. CONCLUSION Patients with spine fractures and ASD are at high risk for complications and death and should be counseled accordingly. Multilevel posterior segmental instrumentation allows effective fracture healing. AS and DISH patients represent similar patient populations for the purpose of treatment and future research.

The evidence for intraoperative neurophysiological monitoring in spine surgery: does it make a difference?

Abstract: Objective The objective of this article was to undertake a systematic review of the literature to determine whether IOM is able to sensitively and specifically detect intraoperative neurologic injury during spine surgery and to assess whether IOM results in improved outcomes for patients during these procedures. Summary and background data Although relatively uncommon, perioperative neurologic injury, in particular spinal cord injury, is one of the most feared complications of spinal surgery. Intraoperative neuromonitoring (IOM) has been proposed as a method which could reduce perioperative neurologic complications after spine surgery. Methods A systematic review of the English language literature was undertaken for articles published between 1990 and March 2009. MEDLINE, EMBASE, and Cochrane Collaborative Library databases were searched, as were the reference lists of published articles examining the use of IOM in spine surgery. Two independent reviewers assessed the level of evidence quality using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) criteria, and disagreements were resolved by consensus. Results A total of 103 articles were initially screened and 32 ultimately met the predetermined inclusion criteria. We determined that there is a high level of evidence that multimodal IOM is sensitive and specific for detecting intraoperative neurologic injury during spine surgery. There is a low level of evidence that IOM reduces the rate of new or worsened perioperative neurologic deficits. There is very low evidence that an intraoperative response to a neuromonitoring alert reduces the rate of perioperative neurologic deterioration. Conclusion Based on strong evidence that multimodality intraoperative neuromonitoring (MIOM) is sensitive and specific for detecting intraoperative neurologic injury during spine surgery, it is recommended that the use of MIOM be considered in spine surgery where the spinal cord or nerve roots are deemed to be at risk, including procedures involving deformity correction and procedures that require the placement of instrumentation. There is a need to develop evidence-based protocols to deal with intraoperative changes in MIOM and to validate these prospectively.

Off-Label Use of Bone Morphogenetic Proteins in the United States Using Administrative Data

Abstract: Study Design. Epidemiological study using national administrative data. Objective. To evaluate the temporal trends in on-label and off-label bone morphogenetic protein (BMP) usage in primary and revision spine fusion by spine region and surgical approach, and nonspine applications in the United States from 2002 to 2007. Summary of Background Data. The prevalence of BMP usage for spine fusion has been on the rise, but its use has not been stratified by surgical approach, particularly for lumbar fusion where it has only been Food And Drug Administration-approved for anterior lumbar interbody fusion (ALIF). Methods. The prevalence of BMP usage in the United States was evaluated using the Nationwide Inpatient Sample between October 1, 2002 and December 31, 2007. The Nationwide Inpatient Sample is the single largest all-payer inpatient care database in the United States. The principal procedure associated with BMP use was determined, and the prevalence of BMP use was calculated for various population subgroups. Results. A total of 340,251 inpatient procedures with BMP usage were identified. Between 2003 and 2007, the annual number of procedures involving BMP increased by 4.3-fold from 23,900 to 103,194. Spine fusion accounted for the vast majority (92.8%) of principal procedures with BMP. The predominant use of BMP was in primary posterior lumbar interbody fusion or transforaminal lumbar interbody fusion (PLIF/TLIF) (30.0%), followed by primary posterolateral spine fusion (20.4%), primary ALIF (16.6%), primary cervical fusions (13.6%), and primary thoracolumbar fusions (3.9%). Of primary ALIF with BMP, 19.3% did not involve the implantation of an interbody device. Conclusion. At least 85% of principal procedures using BMP were for off-label applications. With uncertainty regarding the risks of using BMP in certain off-labelapplications, further research will be needed to better define the appropriate indications. Our study also demonstrates that disparities in the differential rates of BMP use exist in the spine fusion population.

Minimally invasive surgery: lateral approach interbody fusion: results and review.

Abstract: Study Design. A retrospective review of patients treated at 2 institutions with anterior lumbar interbody fusion using a minimally invasive lateral retroperitoneal approach, and review of literature. Objective. To analyze the outcomes from historical literature and from a retrospectively compiled database of patients having undergone anterior interbody fusions performed through a lateral approach. Summary of Background Data. A paucity of published literature exists describing outcomes following lateral approach fusion surgery. Methods. Patients treated with extreme lateral interbody fusion (XLIF) were identified through retrospective chart review. Treatment variables included operating room (OR) time, estimated blood loss (EBL), length of hospital stay (LOS), complications, and fusion rate. A literature review, using the National Center for Biotechnology Information databases PubMed/MEDLINE and Google Scholar, yielded 14 peer-reviewed articles reporting outcomes scoring, complications, fusion status, long-term follow-up, and radiographic assessments related to XLIF. Published XLIF results were summarized and evaluated with current study data. Results. A total of 84 XLIF patients were included in the current cohort analysis. OR time, EBL, and length of hospital stay averaged 199 minutes, 155 mL, and 2.6 days, respectively, and perioperative and postoperative complication rates were 2.4% and 6.1%. Mean follow-up was 15.7 months. Sixty-eight patients showed evidence of solid arthrodesis and no subsidence on computed tomography and flexion/extension radiographs. Results were within the ranges of those in the literature. Literature review identified reports of significant improvements in clinical outcomes scores, radiographic measures, and cost effectiveness. Conclusion. Current data corroborates and contributes to the existing body of literature describing XLIF outcomes. Procedures are generally performed with short OR times, minimal EBL, and few complications. Patients recover quickly, requiring minimal hospital stay, although transient hip/thigh pain and/or weakness is common. Long-term outcomes are generally favorable, with maintained improvements in patient-reported pain and function scores as well as radiographic parameters, including high rates of fusion.

Low back pain in primary care: costs of care and prediction of future health care utilization.

Abstract: Study design Cost of illness study alongside a randomized controlled trial. Objective To describe the costs of care for patients with low back pain (1) and to identify patient characteristics as predictors for high health care cost during a 1-year follow-up (2). Summary of background data Low back pain (LBP) is one of the leading causes of high health care costs in industrialized countries (Life time prevalence, 70%). A lot of research has been done to improve primary health care and patients' prognosis. However, the cost of health care does not necessarily follow changes in patient outcomes. Methods General practitioners (n = 126) recruited 1378 patients consulting for LBP. Sociodemographic data, pain characteristics, and LBP-related cost data were collected by interview at baseline and after 6 and 12 months. Costs were evaluated from the societal perspective. Predictors of high cost during the subsequent year were studied using logistic regression analysis. Results Mean direct and indirect costs for LBP care are about twice as high for patients with chronic LBP compared to acutely ill patients. Indirect costs account for more than 52% to 54% of total costs. About 25% of direct costs refer to therapeutic procedures and hospital or rehabilitational care. Patients with high disability and limitations in daily living show a 2- to 5-fold change for subsequent high health care costs. Depression seems to be highly relevant for direct health care utilization. Conclusion Interventions designed to reduce high health care costs for LBP should focus on patients with severe LBP and depressive comorbidity. Our results add to the economic understanding of LBP care and may give guidance for future actions on health care improvement and cost reduction.

Minimally invasive transforaminal lumbar interbody fusion for the treatment of degenerative lumbar diseases.

Abstract: Study Design. Prospective cohort study. Objective. To determine whether minimally invasive transforaminal lumbar interbody fusion (TLIF) using the tubular retractor system reduces the approach-related morbidity inherent in conventional open surgery. Summary of Background Data. Posterior lumbar fusion using the tubular retractor system has been reported and described well. Supporters have claimed that minimally invasive techniques reduce soft-tissue trauma, blood loss, postoperative pain, transfusion needs, and the length of hospital stay, as compared with reports describing the traditional open procedure. However, there are few studies of minimally invasive TLIF, especially studies that directly compared minimally invasive and open approaches in a single center. Methods. Between May 2005 and December 2006, a total of 62 patients underwent 1-level TLIF by 1 surgeon in 1 hospital. Of 62 patients, 32 underwent minimally invasive TLIF using the tubular retractor system, and the other 30 underwent the traditional open procedure. The operative duration, blood loss, complications, and recovery time were recorded. The clinical outcomes were evaluated by the Oswestry Disability Index and the Visual Analog Scale. The soft-tissue injury was assessed by measuring serum creatine kinase. Radiographic images were obtained before surgery and during follow-up. Results. The minimally invasive group was found to have reduced blood loss, fewer transfusions, less postoperative back pain, lower serum creatine kinase on the third postoperative day, a shorter time to ambulation, and a briefer hospital stay. The Oswestry Disability Index and Visual Analog Scale scores were significantly lower in the minimally invasive group during follow-up. However, the open group had a shorter operative duration. The complications in the 2 groups were similar, but 2 cases of screw malposition occurred in the minimally invasive group. Conclusion. Minimally invasive TLIF as a management of 1-level degenerative lumbar diseases is superior to the traditional open procedure in terms of postoperative back pain, total blood loss, need for transfusion, time to ambulation, length of hospital stay, soft-tissue injury, and functional recovery. However, this procedure takes longer operative duration and requires close attention to the risk of technical complications. Longer-term studies involving a larger sample are needed to validate the long-term efficacy of minimally TLIF.

Evaluation of proximal junctional kyphosis in adolescent idiopathic scoliosis following pedicle screw, hook, or hybrid instrumentation.

Abstract: Study design Retrospective review. Objective To compare the incidence of and risk factors for proximal junctional kyphosis (PJK) in adolescent idiopathic scoliosis (AIS) following posterior spinal fusion using hook, pedicle screw, or hybrid constructs. Summary of background data Proximal junctional kyphosis is a recently recognized phenomenon in adults and adolescents after AIS surgery. The postoperative effect on PJK with the use of hooks, hybrid constructs, or screws has not been compared in a multicenter study to date. Methods From a multicenter database, the preoperative and 2-year follow-up radiographic measurements from 283 patients with AIS treated with posterior spinal fusion using hooks (group 1, n = 51), hybrid constructs (group 2, n = 177), pedicle screws (group 3, n = 37), and pedicle screws with hooks only at the top level (group 4, n = 18) were compared. Results The average proximal level kyphosis at 2 years after surgery was 8.2 degrees (range -1 to 18) in the all screw constructs, representing a significant increase when compared with hybrid and all hook constructs, 5.7 degrees (P = 0.02) and 5.0 degrees (P = 0.014), respectively. Conversely, average postoperative T5-T12 kyphosis was significantly less (P = 0.016) in the screw group compared with the all hook group. Of potential interest, but currently not statistically significant, was the trend towards a decrease in proximal kyphosis in constructs with all pedicle screws except hooks at the most cephalad segment, 6.4 degrees . The incidence of PJK (assuming PJK is a kyphotic deformity greater than 15 degrees ) was 0% in group 1, 2.3% in group 2, 8.1% in group 3, and 5.6% in group 4 (P = 0.18). Patients with PJK had an increased body mass index compared with those who did not meet criteria for PJK (P = 0.013). Conclusion Adjacent level proximal kyphosis was significantly increased with pedicle screws, but the clinical significance of this is unclear. A potential solution is the substitution of hooks at the upper-instrumented vertebrae, but further investigation is required.

Twelve-months Follow-Up in Forty-Nine Patients With Acute/Semiacute Osteoporotic Vertebral Fractures Treated Conservatively or With Percutaneous Vertebroplasty: A Clinical Randomized Study

Abstract: Study design Clinical randomized study. Objective Percutaneous vertebroplasty is compared to conservative treatment in patients with acute or subacute osteoporotic vertebral fractures with respect to pain, physical and mental outcomes. The risk of vertebral fractures adjacent to treated levels is assessed. Summary of background data There are some disagreements of the benefits of PVP for the treatment of acute osteoporotic vertebral fractures, but the long-term clinical outcome of PVP compared to conservative treatment has not been evaluated in a randomized study. Methods The 3-months follow-up of this study has been published previously, and here we report the completed 12-months analysis. About 50 patients (41 females) were included from January 2001 until January 2008. Patients with vertebral fractures less than 8 weeks old were included and randomized to either PVP or conservative treatment. Pain was assessed with a visual analogue scale. Physical and mental outcomes were assessed by validated questionnaires and tests. Tests, questionnaires, and plain radiographs were performed at the inclusion and after 3 and 12 months. Results Pain score before and after the operation in the PVP group was 7.9 and 2.0, respectively. There was no difference between the groups concerning pain at the 3- and 12-months follow-up. Supplementary assessment of back pain 1 month after discharge from hospital showed a significant lower VAS score in the PVP group over the conservative group. In the study period, 2 adjacent fractures in the PVP group and no adjacent fractures in the conservative group were registered. Conclusion PVP is a good treatment for some patients with acute/subacute painful osteoporotic vertebral fractures, but the majority of fractures will heal after 8 to 12 weeks of conservative treatment with subsequent decline in pain. The risk of new fractures needs further research.

Complications related to osteobiologics use in spine surgery: a systematic review.

Abstract: Study design Systematic review. Objective The objectives of this systematic review were to identify the character and rates of complications in patients after the use of BMP in spine fusion surgery and to determine whether there is a dose-response relationship of BMP with complications. Summary of background data BMP is used on-label for ALIF with LT-CAGE and off-label for various spine fusion applications in the cervical, thoracic, and lumbar spines because of its effectiveness in promoting arthrodesis. Multiple studies published over the past several years have highlighted complications associated with BMP in a variety of clinical fusion scenarios. There are no systematic reviews on this topic, and thus, the complication profile of off-label use or physician directed use of BMP in spinal fusion surgery is not well characterized. Some of the reported complications are unique to BMP, which underscores the need for this thorough literature review. Methods A systematic review of the English language literature was performed for articles published between 1990 and June 2009. Electronic databases and reference lists of key articles were searched to identify articles examining the use of BMP in spine surgery. Two independent reviewers assessed the level of evidence using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) criteria and disagreements were resolved by consensus. Results Two hundred forty-' articles that assessed outcomes after BMP use in spinal surgery were identified from the literature; of these, 31 articles were selected for inclusion. We determined that multiple complications are associated after the use of rhBMP-2 in both cervical and lumbar spine fusion surgery. There is a mean incidence of 44%, 25%, and 27% of resorption, subsidence, and interbody cage migration reported for lumbar spine interbody fusion surgery although reoperation or long-term detrimental effect was rare. Cervical studies report a mean 5.8% of postoperative soft tissue problems, including dysphagia, when rhBMP-2 is used for ventral cervical fusion. It was determined that the strength of evidence of the peer-reviewed literature that report on types of complications is high for the lumbar and low for the cervical spine, respectively, and that the current strength of evidence on rates of complications with BMP is moderate and low, respectively. Conclusion The complication profile of BMP-2 for ALIF with LT-CAGE is well characterized. Because of the lack of substantive data, the same is not true for other types of lumbar fusions, or for cervical or thoracic fusion applications. BMP has been associated with a variety of unique complications in the ventral cervical and lumbar spines. The published data on BMP fail to precisely profile this product's use in fusion surgery; hence, it should be used only after a careful consideration of the relevant data. Well-designed and executed studies are necessary to completely define the incidence of various complications relative to type of BMP, type and region of fusion, surgical technique, dose, and carrier, and importantly, to define the natural history and management of associated complications.

Disc regeneration therapy using marrow mesenchymal cell transplantation: a report of two case studies.

Abstract: Study design Marrow mesenchymal cells (MSCs) contain stem cells and possess the ability to regenerate bone, cartilage, and fibrous tissues. Here, we applied this regenerative ability to intervertebral disc regeneration therapy in an attempt to develop a new spinal surgery technique. Objective We analyzed the regenerative restoration ability of autologous MSCs in the markedly degenerated intervertebral discs. Summary of background data Fusion for lumbar intervertebral disc instability improves lumbago. However, fused intervertebral discs lack the natural and physiologic functions of intervertebral discs. If intervertebral discs can be regenerated and repaired, then damage to adjacent intervertebral discs can be avoided. We verified the regenerative ability of MSCs by animal studies, and for the first time, performed therapeutic intervertebral disc regeneration therapy in patients and obtained favorable findings. Methods Subjects were 2 women aged 70 and 67 years; both patients had lumbago, leg pain, and numbness. Myelography and magnetic resonance imaging showed lumbar spinal canal stenosis, and radiograph confirmed the vacuum phenomenon with instability. From the ilium of each patient, marrow fluid was collected, and MSCs were cultured using the medium containing autogenous serum. In surgery, fenestration was performed on the stenosed spinal canal and then pieces of collagen sponge containing autologous MSCs were grafted percutaneously to degenerated intervertebral discs. Results At 2 years after surgery, radiograph and computed tomography showed improvements in the vacuum phenomenon in both patients. On T2-weighted magnetic resonance imaging, signal intensity of intervertebral discs with cell grafts was high, thus indicating high moisture contents. Roentgenkymography showed that lumbar disc instability improved. Symptom was alleviated in both patients. Conclusion The intervertebral disc regeneration therapy using MSC brought about favorable results in these 2 cases. It seems to be a promising minimally invasive treatment.

National trends in anterior cervical fusion procedures.

Abstract: Study design Population-based database analysis. Objective To analyze trends in patient- and healthcare-system-related characteristics, utilization and outcomes associated with anterior cervical spine fusions. Summary of background data Anterior cervical decompression and spine fusion (ACDF) is one of the most commonly performed surgical procedures of the spine. However, few data analyzing trends in patient- and healthcare-system-related characteristics, utilization and outcomes exist. Methods Data from 1990 to 2004 collected in the National Hospital Discharge Survey were accessed. ACDF procedures were identified. Five-year periods of interest (POI) were created for temporal analysis and changes in the prevalence and utilization of this procedure as well as in patient- and healthcare-system-related variables were examined. The changes in the occurrence of procedure-related complications were evaluated. Results An estimated total of 771,932 discharges after ACDF were identified. Temporally, an almost 8-fold increase in total prevalence was accompanied by a similar increase in utilization (23/100.000 civilians/POI to 157/100.000/civilians/POI). The highest increase in utilization was observed in those > or =65 years (28-fold). Average age increased from 47.2 years to 50.5 years over time. Length of hospital stay decreased from 5.17 days to 2.38 days. Overall procedure-related complication rates decreased from 4.6% to 3.03%. The prevalence of hypertension, diabetes mellitus, hypercholesterolemia, obesity, pulmonary, and coronary artery increased over time among patients undergoing ACDF. Conclusion Despite limitations inherent to secondary analysis of large databases, we identified a number of significant changes in the utilization, demographics, and outcomes associated with ACDF, which can be used to assess the effect of changes in medical care, direct health care resources, and future research. The effect of the increased prevalence of comorbidities on medical practice remains to be evaluated. Further studies are necessary to evaluate causal relationships.

Braces for idiopathic scoliosis in adolescents

Abstract: BACKGROUND Idiopathic scoliosis is a three-dimensional deformity of the spine. The most common form is diagnosed in adolescence. While adolescent idiopathic scoliosis (AIS) can progress during growth and cause a surface deformity, it is usually not symptomatic. However, in adulthood, if the final spinal curvature surpasses a certain critical threshold, the risk of health problems and curve progression is increased. OBJECTIVES To evaluate the efficacy of bracing for adolescents with AIS versus no treatment or other treatments, on quality of life, disability, pulmonary disorders, progression of the curve, and psychological and cosmetic issues. SEARCH METHODS We searched CENTRAL, MEDLINE, EMBASE, five other databases, and two trials registers up to February 2015 for relevant clinical trials. We also checked the reference lists of relevant articles and conducted an extensive handsearch of grey literature. SELECTION CRITERIA Randomized controlled trials (RCTs) and prospective controlled cohort studies comparing braces with no treatment, other treatment, surgery, and different types of braces for adolescent with AIS. DATA COLLECTION AND ANALYSIS We used standard methodological procedures expected by The Cochrane Collaboration. MAIN RESULTS We included seven studies (662 participants). Five were planned as RCTs and two as prospective controlled trials. One RCT failed completely, another was continued as an observational study, reporting also the results of the participants that had been randomized.There was very low quality evidence from one small RCT (111 participants) that quality of life (QoL) during treatment did not differ significantly between rigid bracing and observation (mean difference (MD) -2.10, 95% confidence interval (CI) -7.69 to 3.49). There was very low quality evidence from a subgroup of 77 adolescents from one prospective cohort study showing that QoL, back pain, psychological, and cosmetic issues did not differ significantly between rigid bracing and observation in the long term (16 years).Results of the secondary outcomes showed that there was low quality evidence that rigid bracing compared with observation significantly increased the success rate in 20° to 40° curves at two years' follow-up (one RCT, 116 participants; risk ratio (RR) 1.79, 95% CI 1.29 to 2.50). There was low quality evidence that elastic bracing increased the success rate in 15° to 30° curves at three years' follow-up (one RCT, 47 participants; RR 1.88, 95% CI 1.11 to 3.20).There is very low quality evidence from two prospective cohort studies with a control group that rigid bracing increases the success rate (curves not evolving to 50° or above) at two years' follow-up (one study, 242 participants; RR 1.50, 95% CI 1.19 to 1.89) and at three years' follow-up (one study, 240 participants; RR 1.75, 95% CI 1.42 to 2.16). There was very low quality evidence from a prospective cohort study (57 participants) that very rigid bracing increased the success rate (no progression of 5° or more, fusion, or waiting list for fusion) in adolescents with high degree curves (above 45°) (one study, 57 adolescents; RR 1.79, 95% CI 1.04 to 3.07 in the intention-to-treat (ITT) analysis).There was low quality evidence from one RCT that a rigid brace was more successful than an elastic brace at curbing curve progression when measured in Cobb degrees in low degree curves (20° to 30°), with no significant differences between the two groups in the subjective perception of daily difficulties associated with wearing the brace (43 girls; risk of success at four years' follow-up: RR 1.40, 1.03 to 1.89). Finally, there was very low quality evidence from one RCT (12 participants) that a rigid brace with a pad pressure control system is no better than a standard brace in reducing the risk of progression.Only one prospective cohort study (236 participants) assessed adverse events: neither the percentage of adolescents with any adverse event (RR 1.27, 95% CI 0.96 to 1.67) nor the percentage of adolescents reporting back pain, the most common adverse event, were different between the groups (RR 0.72, 95% CI 0.47 to 1.10). AUTHORS' CONCLUSIONS Due to the important clinical differences among the studies, it was not possible to perform a meta-analysis. Two studies showed that bracing did not change QoL during treatment (low quality), and QoL, back pain, and psychological and cosmetic issues in the long term (16 years) (very low quality). All included papers consistently showed that bracing prevented curve progression (secondary outcome). However, due to the strength of evidence (from low to very low quality), further research is very likely to have an impact on our confidence in the estimate of effect. The high rate of failure of RCTs demonstrates the huge difficulties in performing RCTs in a field where parents reject randomization of their children. This challenge may prevent us from seeing increases in the quality of the evidence over time. Other designs need to be implemented and included in future reviews, including 'expertise-based' trials, prospective controlled cohort studies, prospective studies conducted according to pre-defined criteria such as the Scoliosis Research Society (SRS) and the international Society on Scoliosis Orthopedic and Rehabilitation Treatment (SOSORT) criteria. Future studies should increase their focus on participant outcomes, adverse effects, methods to increase compliance, and usefulness of physiotherapeutic scoliosis specific exercises added to bracing.

Proximal junctional vertebral fracture in adults after spinal deformity surgery using pedicle screw constructs: analysis of morphological features.

Abstract: STUDY DESIGN A retrospective comparative study. OBJECTIVE To investigate the morphologic features of proximal vertebral fractures in adults following spinal deformity surgery using segmental pedicle screw instrumentation. SUMMARY OF BACKGROUND DATA Fractures above pedicle screw constructs are a clinical problem that warrants further investigation for prevention and treatment. METHODS Ten adult patients (6 lumbar scoliosis, 4 degenerative sagittal imbalance) who underwent segmental spinal instrumented fusion were analyzed. Patients were divided into 2 groups according to the features of vertebral fracture: upper instrumented vertebral collapse + adjacent vertebral subluxation (SUB group: n = 5), and adjacent vertebral fracture (Fracture group: n = 5). RESULTS Both groups demonstrated a high frequency of osteopenia and all patients in the SUB group had comorbidities before surgery. The SUB group demonstrated a shorter interval between initial surgery and the fracture (subluxation: 3 +/- 1.9 months; fracture: 33 +/- 25.3 months, P < 0.05), and hypokyphosis (T5-T12) in the thoracic region before surgery (SUB: 13 degrees +/- 6.4 degrees; fracture: 33 degrees +/- 15.6 degrees). Both groups demonstrated severe global sagittal imbalance (SUB: 151 +/- 62.8 mm; fracture: 94 +/- 102.2 mm), and hypolordosis (T12-S1) in the lumbar spine (SUB: -19 degrees +/- 24.4 degrees ; fracture: -33 degrees +/- 22.7 degrees) before surgery. Global sagittal imbalance in the SUB group was corrected to 8 +/- 17.4 mm immediately postoperative (P < 0.05), but increased to 64 +/- 19.9 mm after the junctional fractures (P < 0.05). The SUB group demonstrated a significantly higher wedging rate (SUB: 65% +/- 12.4%; fracture: 36% +/- 16.0%, P < 0.05) and greater local kyphosis (SUB: 42 degrees +/- 11.1 degrees; fracture: 17 degrees +/- 4.1 degrees, P < 0.05) after the fracture. Two of 5 patients in the SUB group demonstrated severe neurologic deficit from E to B after the fractures by a modified Frankel classification. CONCLUSION Old age, osteopenia, preoperative comorbidities, and severe global sagittal imbalance were found to be frequent in patients with proximal junctional fracture. In addition, marked correction of sagittal malalignment might be considered as a risk factor of upper instrumented vertebra collapse followed by adjacent vertebral subluxation, which occurred in the first 6 months after corrective surgery with the potential for causing severe neurologic deficit because of the severe local kyphotic deformity.

The impact of body mass index on the prevalence of low back pain: the HUNT study.

Abstract: Study design A cross-sectional population-based study. Objective To examine the association between body mass index and chronic low back pain, with adjustment for potential confounders. Summary of background data Although many studies have investigated this association, it is still unclear whether there is a general relationship between body mass index and low back pain which applies to all populations. Methods This study is based on data collected in the HUNT 2 study in the county of Nord-Trondelag in Norway between 1995 and 1997. Among a total of 92,936 persons eligible for participation, 30,102 men and 33,866 women gave information on body mass index and indicated whether they suffered from chronic low back pain (69% participation rate). A total of 6293 men (20.9%) and 8923 women (26.3%) experienced chronic low back pain. Relations were assessed by logistic regression of low back pain with respect to body mass index and other variables. Results In both sexes, a high body mass index was significantly associated with an increased prevalence of low back pain. In men the estimated OR per 5 kg/m increase in body mass index was 1.07 (95% CI: 1.03-1.12) and in women 1.17 (95% CI: 1.14-1.21), after adjustment for age, with a significantly stronger association in women. Additional adjustment for education, smoking status, leisure time physical activity, employment status, and activity at work hardly affected these associations. No interactions were found with most other factors. Conclusion This large population-based study indicates that obesity is associated with a high prevalence of low back pain. Further studies are needed to determine if the association is causal.

Sacropelvic fixation: techniques and complications.

Abstract: Study design Literature-based topic review. Objective To review the indications and techniques for different sacropelvic fixation methods and to outline important associated complications. Summary of background data Despite all the advances and new developments in spinal instrumentation techniques, fixation at the lumbosacral junction continues to be one of the important challenges to spine surgeons. The poor bone quality of the sacrum, the complex regional anatomy, and the tremendous biomechanical forces at the lumbosacral junction contribute to the high rates of instrumentation-related problems. Although many techniques for sacropelvic fixation have been attempted, only a few are still widely used because of the high rate of complications associated with some of those techniques. Methods Review of literature and expert opinion. Conclusion There are many indications for sacropelvic fixation. Long fusions to the sacrum are the most common reasons for extending the instrumentation to the pelvis. Spinal surgeons performing complex spinal reconstruction should be familiar with the currently available techniques, including their potential risks and complications. Surgical treatment decisions should be based on an individual patient's anatomy and abnormalities, and on the surgeon's experience.

Sagittal parameters of global spinal balance: normative values from a prospective cohort of seven hundred nine Caucasian asymptomatic adults.

Abstract: Study design Prospective study of normal sagittal global spinal balance in the Caucasian adult population. Objective To document values for parameters of global spinal balance in 709 asymptomatic adults without spinal pathology. Summary of background data Previous studies have investigated sagittal spinal balance in the normal population, but there is still a need for a large prospective database with normative values on the basis of gender and age. Methods Spinosacral angle (SSA), spinal tilt (ST), and C7 translation ratio were evaluated in 709 asymptomatic adults (354 males and 355 females). Position of C7 plumbline relative to sacrum and hip axis (HA) was also assessed. Comparisons on the basis of gender were performed using analyses of covariance with age as covariate. Relationships between parameters and age were assessed using Spearman's coefficients. Results Mean SSA, ST, and C7 translation ratio were respectively 130.4° ± 8.1°, 90.8° ± 3.4°, and 0.1° ± 1.9°. Mean ± 2 standard deviations were respectively 110° to 150° for SSA and 85° to 100° for ST. Mean SSA and ST were higher in females but by less than 2°. C7 plumbline was behind the HA in 86% of subjects. Correlations between global balance and age were small (-0.1 ≤ r ≤ 0.1), with only 1 correlation reaching statistical significance (SSA vs. age; r = -0.1), reflecting a slight tendency for SSA to decrease with age. There was no relationship between ST and age. Conclusion Asymptomatic adults tend to stand with a stable global balance and it is expected that 95% of normal adults have an SSA and ST between 110° to 150° and 85° to 100°, respectively. C7 plumbline in front of the HA is not necessarily associated with a spinal pathology. Results suggest that in adults, anterior displacement of C7 plumbline with respect to sacrum cannot be attributed solely to aging and should raise a suspicion for the risk of developing spinal pathology.

Minimally invasive spine surgery.

Abstract: This article reviews the rationale, suggested benefits, and techniques of minimally invasive surgery (MIS) of the spine. While the efficacy and outcomes of open spinal decompression and fusion procedures have been validated in numerous longitudinal studies, these surgeries typically involve significant soft-tissue dissection and muscle retraction. MIS techniques aim to minimize iatrogenic damage to the soft tissues around the spine while allowing surgeons to perform effective decompression and fusion procedures. Here we summarize the rationale for the trend toward spinal MIS and highlight the more common procedures.

The influence of perioperative risk factors and therapeutic interventions on infection rates after spine surgery: a systematic review.

Abstract: STUDY DESIGN Systematic review. OBJECTIVE The objectives of this systematic review were to determine the patient and perioperative risk factors that contribute to infections after spine surgery and to examine the level of evidence to support the use of therapeutic interventions to reduce infection rates. SUMMARY OF BACKGROUND DATA Infection continues to be one of the most common and feared complications after spine surgery. As such, it is used as a sentinel event for quality assurance processes. It is clear that the causes of infections after spine surgery are multifactorial and numerous patient- and procedure-related factors have been proposed as contributory elements. In addition, numerous perioperative adjuncts have been suggested to reduce infection rates. METHODS A systematic review of the English-language literature (published between January 1990 and June 2009) was undertaken to identify articles examining risk factors associated with and adjunct treatment measures for preventing surgical-site infections. Two independent reviewers assessed the level of evidence quality using the Grading of Recommendations Assessment, Development, and Evaluation criteria, and disagreements were resolved by consensus. RESULTS Of the 127 articles identified, 32 met the criteria to undergo full-text review. Individual patient, operative, and perioperative variables have been identified that are associated with increased infection rates (i.e., older age, obesity, diabetes, malnutrition, higher American Society of Anesthesiologists score, posterior approaches, and blood transfusions) but these variables have not been combined to provide individual patient risks based on a composite of factors (e.g., risk stratification). Of the surgical adjuncts investigated, only irrigation with dilute betadine solution showed moderate support for reducing infection rates. CONCLUSION It is clear that the causes of postoperative spinal site infections are multifactorial and related to a complex interplay of patient and procedural influences. Because of these complexities, for any individual and surgical procedure, predictable infection rates likely exist that do not extrapolate to 0. Although we have identified factors associated with increased infection rates, further studies will be required to allow multifactorial risk stratification for individual patients and to further investigate the use of therapeutic adjuncts.

Prevalence, distribution, and morphology of ossification of the ligamentum flavum: a population study of one thousand seven hundred thirty-six magnetic resonance imaging scans.

Abstract: Study Design. Large scale, cross-sectional imaging study of a general population. Objectives. To evaluate the prevalence, morphology, and distribution of ossification of the ligamentum flavum (OLF) in a population, and synthesize the scientific literature on the prevalence of OLF and some factors associated with its occurrence. Summary of Background Data. OLF is a rare disease in which the pathogenesis has not been conclusively established. Little is known about its epidemiology. To date, there is no study that comprehensively assessed the distribution and prevalence of OLF in the whole spine using magnetic resonance imaging (MRI). Methods. A total of 1736 southern Chinese volunteers (1068 women; 668 men) between 8 and 88 years of age (mean, 38 years) were recruited by open invitation. MRI was administered to all the participants. T2-weighted, 5-mm spin-echo MRI sequences of the whole spine were obtained. Presence of OLF was identified as an area of low signal intensity in the T2 sagittal sequence located in the posterior part of the spinal canal, and subsequently confirmed by computed tomography scans showing areas of ossification within the ligamentum flavum. The distribution of OLF was classified into 3 types: the isolated type, continuous type, and noncontinuous type. While the morphology of the lesion was classified into triangular, round, and beak shapes based on the pattern of ossification on T2-weighted sagittal MRIs. Results. OLF was identified in a total of 66 subjects or 3.8% of the population (52 women and 14 men). In 45(68.2%) cases, OLF was present at a single-level (isolated type), whereas in 21 (31.8%) cases OLF was present at multiple levels. The isolated type was found in 45 (68.2%) cases, continuous type in 11 (16.7%), and noncontinuous type in 10 (15.2%). The most common site of involvement is the lower thoracic spine, but they can also occur in the upper thoracic spine. The majority of the segments had a round morphology (n = 75: 81.5%), while 17 (18.5%) segments were triangular in shape. A literature review of the past 26 years showed only 4 reports on the prevalence of OLF, all were in special patient groups. Conclusion. Case reports have described postoperative paraplegia from failure to identify and decompress all stenotic segments of OLF. This study demonstrated that OLF is not uncommon, and that some 15% of the lesions are noncontinuous, and therefore could be missed. The authors recommend that for patients undergoing surgical decompression for 1 level of OLF, the whole spine should be routinely screened for other stenotic segments. Failure to do so could result in paraplegia from the nondecompressed levels.

Minimally invasive transforaminal lumbar interbody fusion: a review of techniques and outcomes.

Abstract: Study design Review of published literature. Objective To review the available medical literature reporting results after minimally invasive transforaminal lumbar interbody fusion (MIS TLIF) and evaluate functional and radiographic outcomes with those following open TLIF and open posterior lumbar interbody fusion (PLIF) procedures. Summary of background data Minimally invasive spine techniques aim to reduce approach-related surgical morbidity without compromising operative and clinical outcomes. MIS TLIF is increasingly being used for the management of various lumbar degenerative diseases. Despite the limited number of well-designed clinical studies, the available published data suggest potential advantages over its open posterior-approach lumbar interbody fusion counterparts. Such benefits include less intraoperative blood loss, less need for blood transfusions, shorter hospital course, and less postoperative pain. Methods Literature examining posterior-approach interbody fusion techniques (PLIF, TLIF, and MIS TLIF) was collected using the National Center for Biotechnology Information database and PubMed/MEDLINE, and summarized for discussion. Results Literature reports of MIS TLIF generally show comparable or improved clinical outcomes when compared with those following open posterior interbody fusion techniques. Additionally, significantly less blood loss, hospital stay, and complications were generally reported, despite slightly longer duration of surgery, especially during early cases in a surgeon's experience. Conclusion More studies designed to provide class I or II data will be needed in the future to further solidify the favorable results observed so far with the MIS TLIF procedure.