Showing papers on "Cobb angle published in 2013"

Proximal junctional kyphosis in primary adult deformity surgery: evaluation of 20 degrees as a critical angle

Abstract: BACKGROUND : Multiple studies have reported on the prevalence of proximal junctional kyphosis (PJK) following spinal deformity surgery; however, none have demonstrated its significance with respect to functional outcome scores or revision surgery. OBJECTIVE : To evaluate if 20° is a possible critical PJK angle in primary adult scoliosis surgery patients as a threshold for worse patient-reported outcomes. METHODS : Clinical and radiographic data of 90 consecutive primary surgical patients at a single institution (2002-2007) with adult idiopathic/degenerative scoliosis and 2-year minimum follow-up were analyzed. Assessment included radiographic measurements, but most notably sagittal Cobb angle of the proximal junctional angle at preoperation, between 1 and 2 months, 2 years, and ultimate follow-up. RESULTS : Prevalence of PJK ≥20° at 3.5 years was 27.8% (n = 25). Those with PJK ≥20° at ultimate follow-up were older (mean 56 vs 46 years), had lower number of levels fused (median 8 vs 11), and were proximally fused to the lower thoracic spine more often than upper thoracic spine (all P < .001). PJK ≥20° was associated with significantly higher body mass index and fusion to the sacrum with iliac screws (P < .016, P < .029, respectively). Scoliosis Research Society outcome score changes were lower for PJK patients, but not significantly different from those in the non-PJK group. CONCLUSION : PJK ≥20° in primary adult idiopathic/degenerative scoliosis does not lead to revision surgery for PJK, but is univariately associated with older age, shorter constructs starting in the lower thoracic spine, obesity, and fusion to the sacrum. The negative results, supported by Scoliosis Research Society outcome data, provide important guidance on the postoperative management of such PJK patients. ABBREVIATIONS : BMI, body mass indexLIV, lowest instrumented vertebraeODI, Oswestry Disability IndexPJ, proximal junctionalPJK, proximal junctional kyphosisSRS, Scoliosis Research SocietyUIV, upper instrumented vertebra.

Early results of a remotely-operated magnetic growth rod in early-onset scoliosis

Abstract: Conventional growing rods are the most commonly used distraction-based devices in the treatment of progressive early-onset scoliosis. This technique requires repeated lengthenings with the patient anaesthetised in the operating theatre. We describe the outcomes and complications of using a non-invasive magnetically controlled growing rod (MCGR) in children with early-onset scoliosis. Lengthening is performed on an outpatient basis using an external remote control with the patient awake. Between November 2009 and March 2011, 34 children with a mean age of eight years (5 to 12) underwent treatment. The mean length of follow-up was 15 months (12 to 18). In total, 22 children were treated with dual rod constructs and 12 with a single rod. The mean number of distractions per patient was 4.8 (3 to 6). The mean pre-operative Cobb angle was 69° (46° to 108°); this was corrected to a mean 47° (28° to 91°) post-operatively. The mean Cobb angle at final review was 41° (27° to 86°). The mean pre-operative distance from T1 to S1 was 304 mm (243 to 380) and increased to 335 mm (253 to 400) in the immediate post-operative period. At final review the mean distance from T1 to S1 had increased to 348 mm (260 to 420). Two patients developed a superficial wound infection and a further two patients in the single rod group developed a loss of distraction. In the dual rod group, one patient had pull-out of a hook and one developed prominent metalwork. Two patients had a rod breakage; one patient in the single rod group and one patient in the dual rod group. Our early results show that the MCGR is safe and effective in the treatment of progressive early-onset scoliosis with the avoidance of repeated surgical lengthenings. Cite this article: Bone Joint J 2013;95-B:75–80.

Measuring procedures to determine the Cobb angle in idiopathic scoliosis: a systematic review

Abstract: Background Scoliosis of the vertebral column can be assessed with the Cobb angle (Cobb 1948). This examination is performed manually by measuring the angle on radiographs and is considered the gold standard. However, studies evaluating the reproducibility of this procedure have shown high variability in intra- and inter-observer agreement. Because of technical advancements, interests in new procedures to determine the Cobb angle has been renewed. This review aims to systematically investigate the reproducibility of various new techniques to determine the Cobb angle in idiopathic scoliosis and to assess whether new technical procedures are reasonable alternatives when compared to manual measurement of the Cobb angle.

Factors associated with kyphosis progression in older women: 15 years' experience in the study of osteoporotic fractures.

Abstract: Age-related hyperkyphosis is thought to be a result of underlying vertebral fractures, but studies suggest that among the most hyperkyphotic women, only one in three have underlying radiographic vertebral fractures. Although commonly observed, there is no widely accepted definition of hyperkyphosis in older persons, and other than vertebral fracture, no major causes have been identified. To identify important correlates of kyphosis and risk factors for its progression over time, we conducted a 15-year retrospective cohort study of 1196 women, aged 65 years and older at baseline (1986 to 1988), from four communities across the United States: Baltimore County, MD; Minneapolis, MN; Portland, OR; and the Monongahela Valley, PA. Cobb angle kyphosis was measured from radiographs obtained at baseline and an average of 3.7 and 15 years later. Repeated measures, mixed effects analyses were performed. At baseline, the mean kyphosis angle was 44.7 degrees (SE = 0.4, SD = 11.9) and significant correlates included a family history of hyperkyphosis, prevalent vertebral fracture, low bone mineral density, greater body weight, degenerative disc disease, and smoking. Over an average of 15 years, the mean increase in kyphosis was 7.1 degrees (SE = 0.25). Independent determinants of greater kyphosis progression were prevalent and incident vertebral fractures, low bone mineral density and concurrent bone density loss, low body weight, and concurrent weight loss. Thus, age-related kyphosis progression may be best prevented by slowing bone density loss and avoiding weight loss.

Type of Anchor at the Proximal Fusion Level Has a Significant Effect on the Incidence of Proximal Junctional Kyphosis and Outcome in Adults After Long Posterior Spinal Fusion

Abstract: Study Design Retrospective review. Objectives To compare the incidence of proximal junctional kyphosis (PJK) and the clinical, radiographic, and functional outcomes in adults undergoing long posterior spinal fusion with transverse process hooks versus pedicle screws at the uppermost instrumented vertebrae. Summary of Background Data Proximal junctional kyphosis often occurs after instrumented long spinal fusion. Although there have been numerous studies of PJK development in adolescents with idiopathic scoliosis, few studies have focused on adults. Methods This study reviewed data on 47 consecutive adult patients who underwent long spinal fusion (five or more levels) with hooks or screws at the uppermost instrumented vertebrae, from 2004 through 2009, and had 2-year radiographic and clinical follow-up. The hook group (20 patients) and screw group (27 patients) were similar in terms of age, gender, and levels fused. Proximal junctional kyphosis was defined as a sagittal Cobb angle of at least 10° between the lower end plate of the uppermost instrumented vertebrae and the upper end plate of the 2 immediately superior vertebrae, and at least 10° of progression from the previous measurement. The groups' radiographs, complications, and functional outcomes (Scoliosis Research Society–22 Patient Questionnaire and the Oswestry Disability Index) were compared using Hotelling's t 2 test (significance, p Results Comparing immediate postoperative and final follow-ups, none of the 20 patients in the hook group versus 8 of 27 patients in the screw group (29.6%) developed PJK (p = .01). There were no statistical differences between groups in major or minor complications rates. At final follow-up, patients with hooks had significantly higher functional scores than those with screws (p Conclusions Transverse process hooks were associated with a lower incidence of PJK and higher functional scores than pedicle screws.

Long-term 2- to 5-year clinical and functional outcomes of minimally invasive surgery for adult scoliosis.

Abstract: Study design A retrospective study. Objective We assess MIS technique's clinical and functional outcomes during a 2- to 5-year period. Summary of background data Traditional surgical approaches for adult scoliosis are associated with significant blood loss and morbidity, in a population that is often elderly with multiple medical comorbidities. Minimally invasive surgery (MIS) represents a newer method of achieving similar long-term outcomes but considerably lower morbidity and complication rates. Methods We reviewed 71 patients who underwent MIS correction of spinal deformity with fusion of 2 or more levels including: degenerative scoliosis (54), idiopathic scoliosis (11), and iatrogenic scoliosis (6). All underwent a combination of 3 MIS techniques: direct lateral interbody fusion (66), axial lumbar interbody fusion (34), and posterior instrumentation (67). Thirty-six patients were staged with direct lateral interbody fusion done first followed by the posterior instrumentation and fusion including axial lumbar interbody fusion done 3 days later. Results Mean age was 64 years (20-84 yr). Mean follow-up was 39 months (24-60 mo). Patients with 1-stage same-day surgery had a mean blood loss of 412 mL and a mean surgical time of 291 minutes. Patients with 2-stage surgery had a mean blood loss of 314 mL and surgical time of 183 minutes for direct lateral interbody fusion and 357 mL and 243 minutes, respectively for posterior instrumentation and axial lumbar interbody fusion. Mean hospital stay was 7.6 days (2-26 d). The mean preoperative Cobb angle was 24.7° (8.3°-65°), which corrected to 9.5° (0.6°-28.8°). Mean preoperative Coronal balance was 25.5 mm, which corrected to 11 mm. Mean preoperative sagittal balance was 31.7 mm and corrected to 10.7 mm. The mean preoperative lumbar apical vertebral translation was 24 mm and corrected to 12 mm. Fourteen patients had adverse events requiring intervention: 4 pseudarthrosis, 4 persistent stenosis, 1 osteomyelitis, 1 adjacent segment discitis, 1 late wound infection, 1 proximal junctional kyphosis, 1 screw prominence, 1 idiopathic cerebellar hemorrhage, and 2 wound dehiscence. Conclusion A combination of 3 novel MIS techniques allows comparable correction of adult spinal deformity, with low pseudarthrosis rates, significantly improved functional outcomes, and excellent clinical and radiological improvement, but considerably lowers morbidity and complication rates at early and long-term follow-up.

Percutaneous short-segment pedicle screw placement without fusion in the treatment of thoracolumbar burst fractures: is it effective?: comparative study with open short-segment pedicle screw fixation with posterolateral fusion

Abstract: Since introduction of the pedicle screw-rod system, short-segment pedicle screw fixation has been widely adopted for thoracolumbar burst fractures (TLBF). Recently, the percutaneous pedicle screw fixation (PPSF) systems have been introduced in spinal surgery; and it has become a popularly used method for the treatment of degenerative spinal disease. However, there are few clinical reports concerning the efficacy of PPSF without fusion in treatment of TLBF. The purpose of this study was to determine the efficacy and safety of short-segment PPSF without fusion in comparison to open short-segment pedicle screw fixation with bony fusion in treatment of TLBF. This study included 59 patients, who underwent either percutaneous (n = 32) or open (n = 27) short-segment pedicle screw fixation for stabilization of TLBF between December 2003 and October 2009. Radiographs were obtained before surgery, immediately after surgery, and at the final follow-up for assessment of the restoration of the spinal column. For radiologic parameters, Cobb angle, vertebral wedge angle, and vertebral body compression ratio were assessed on a lateral thoracolumbar radiograph. For patient’s pain and functional assessment, the visual analogue scale (VAS), the Frankel grading system, and Low Back Outcome Score (LBOS) were measured. Operation time, and the amount of intraoperative bleeding loss were also evaluated. In both groups, regional kyphosis (Cobb angle) showed significant improvement immediately after surgery, which was maintained until the last follow up, compared with preoperative regional kyphosis. Postoperative correction loss showed no significant difference between the two groups at the final follow-up. In the percutaneous surgery group, there were significant declines of intraoperative blood loss, and operation time compared with the open surgery group. Clinical results showed that the percutaneous surgery group had a lower VAS score and a better LBOS at three months and six months after surgery; however, the outcomes were similar in the last follow-up. Both open and percutaneous short-segment pedicle fixation were safe and effective for treatment of TLBF. Although both groups showed favorable clinical and radiologic outcomes at the final follow-up, PPSF without bone graft provided earlier pain relief and functional improvement, compared with open TPSF with posterolateral bony fusion. Despite several shortcomings in this study, the result suggests that ongoing use of PPSF is recommended for the treatment of TLBF.

Prediction of massive blood loss in scoliosis surgery from preoperative variables.

Abstract: Study design A retrospective cohort study. Objective To identify predictors of massive blood loss after scoliosis surgery. Summary of background data Scoliosis surgery may be associated with considerable blood loss. Many blood conservation techniques have been used to reduce the allogeneic transfusion. An ability to identify patients with high risk of massive blood loss preoperatively may be helpful for appropriate use of these techniques. Methods Data of patients undergoing scoliosis surgery between June 1, 2011, and October 31, 2011, were collected. Preoperative information and total blood loss, which was calculated as the sum of intraoperative and postoperative estimated blood loss, were recorded. Patients were divided into 2 groups, retrospectively: group A (n = 95) with the total blood loss more than 30% of estimated blood volume and group B (n = 64) with the total blood loss of 30% of estimated blood volume or less. Preoperative data were compared between the groups. Significant variables were selected for a forward stepwise binary logistic regression analysis to determine the independent risk factors of massive blood loss. Results More than half of the patients (59.7%) undergoing scoliosis surgery had massive blood loss. Patients in group A were shorter (P = 0.01) and had larger preoperative Cobb angle (P Conclusion Risk of massive blood loss (total blood loss > 30% of estimated blood volume) in patients with scoliosis could increase, if they (1) had preoperative Cobb angle larger than 50o or (2) planned to undergo osteotomy or fusion of more than 6 levels.

Risk factors for complications associated with growing-rod surgery for early-onset scoliosis.

Abstract: Study Design. A retrospective multicenter study. Objective. To identify risk factors for postoperative complications associated with growing-rod (GR) surgery for early-onset scoliosis (EOS). Summary of Background Data. Results and complications of GR surgery for EOS have not been adequately studied. Methods. We evaluated clinical and radiographical results from 88 patients with EOS who underwent GR surgery in 12 spine centers in Japan. The mean age at the time of initial surgery was 6.5 ± 2.2 years (range, 1.5–9.8 yr) and the mean follow-up period was 3.9 ± 2.6 years (range, 2.0–12.0 yr). Risk factors for postoperative complications were analyzed using binomial multiple logistic regression analysis. We considered the potential factors of sex, age, number of rod-lengthening procedures, whether a pedicle screw foundation was used, the uppermost level of the proximal foundation and lowermost level of the distal foundation, Cobb angles of the proximal thoracic, main thoracic, and lumbar curves, and the kyphosis angles in the proximal, main thoracic, thoracolumbar, and lumbar spine. Kaplan-Meier analysis was used to determine the complication-free survival rate of GR surgery as a function of the number of surgical procedures. Results. Complications affected 50 of the patients (57%) and were associated with 119 of 538 surgical procedures, with 86 implant-related failures (72%), 19 infections (16%), 3 neurological impairments (3%), and 11 other complications. The most frequent implant-related failure was dislodged implant (71%) and 95% of the dislodgements occurred at the proximal foundation. Kaplan-Meier analysis demonstrated a linear decrease in complication-free rates as the number of rod-lengthening procedures increased. Binomial multiple logistic regression analysis found the following significant independent risk factors: 6 or more rod-lengthening procedures (odds ratio [OR], 6.534), an increase of every 20° in the proximal thoracic Cobb angle (OR, 3.091), and an increase of every 25° in the lumbar lordosis angle (OR, 2.607) in the preoperative condition. Conclusion. Increases in the upper thoracic scoliotic curve, thoracic kyphosis, and number of rod-lengthening procedures are positively associated with an increased risk of complications after GR surgery for EOS. Conclusion. Level of Evidence: 4

Scoliometer measurements of patients with idiopathic scoliosis

Abstract: Background: Patients with idiopathic scoliosis are exposed to approximately 25 radiographic examinations of their spine throughout the clinical follow-up using the Cobb angle. Several non-invasive and radiation-free methods have been proposed to measure scoliotic deformities, including the scoliometer. Objectives: To measure the intra- and interrater reliability of the scoliometer measurements, to assess the correlation of the values obtained by the scoliometer measurements with the Cobb angles obtained by radiography, and to assess the sensitivity and specificity of the scoliometer measurements for the different diagnostic criteria for the referral of idiopathic scoliosis. Method: Sixty-four patients were selected for the study: half with idiopathic scoliosis and half without. The 17 levels of the spine of each volunteer were measured with a scoliometer in the forward bending position. The measurements were performed three times on 42 volunteers by two different raters to obtain data for calculating the reliability values. Anteroposterior radiographs were taken to determine the Cobb angles, which were then compared with the highest trunk rotation value. Sensitivity and specificity were evaluated using radiograph criteria for referral: a Cobb angle of 10° and axial trunk rotation values between 5° and 10°. Results: Excellent intrarater reliability values and very good interrater reliability values were obtained. The correlation between the scoliometer measurements and radiograph analyses was considered good (r=0.7, p<0.05). The highest sensitivity value was for a trunk rotation of 5° at 87%. Conclusions: The scoliometer measurements showed a good correlation with the radiographic measurements.

Skeletal clinical characteristics of osteogenesis imperfecta caused by haploinsufficiency mutations in COL1A1

Abstract: COL1A1 haploinsufficiency mutations lead to the mildest form of osteogenesis imperfecta (OI), OI type I. The skeletal clinical characteristics resulting from such mutations have not been characterized in detail. In this study we assessed 86 patients (36 male, 50 female; mean age 13.3 years; range, 0.6 to 54 years) with COL1A1 haploinsufficiency mutations, of whom 70 were aged 21 years or less (“pediatric” patients). Birth history was positive for fracture or long-bone deformity in 12% of patients. The average rate of long-bone fracture (femur, tibia/fibula, humerus, radius/ulna) in pediatric patients was 0.62 fractures per year, one-half of which affected the tibia/fibula. Long-bone fracture rate was negatively associated with age and lumbar spine areal bone mineral density. Vertebral compression fractures were observed in 71% of the 58 pediatric patients who had lateral spine radiographs. The median number of vertebral fractures was higher for females (median 4; range, 0 to 14) than for males (median 1; range, 0 to 8) (p = 0.03). Lumbar spine areal bone mineral density was negatively associated with the severity of vertebral compression fractures, as reflected in the spine deformity index. Scoliosis was present in about 30% of pediatric patients but the Cobb angle was <30 degrees in all cases. The average final height Z-score was –1.1, representing a deficit of 8 to 10 cm compared to the general population. In summary, OI patients with COL1A1 haploinsufficiency mutations have high rates of significant skeletal involvement. Systematic follow-up of growing patients with COL1A1 haploinsufficiency mutations including radiographic screening for vertebral compression fractures and scoliosis is warranted.

Correction of Lenke 5 adolescent idiopathic scoliosis using pedicle screw instrumentation: does implant density influence the correction?

Abstract: STUDY DESIGN A single-center, retrospective study of 39 consecutive patients with Lenke 5 adolescent idiopathic scoliosis (AIS), all operated by a single surgeon using identical surgical technique and type of instrumentation (pedicle screws). OBJECTIVE The objective of this study is to evaluate the effect of implant density on coronal and sagittal correction in the treatment of Lenke 5 AIS. SUMMARY OF BACKGROUND DATA There is an increasing trend in the use of pedicle screws in spinal corrective surgery. It is reported that decreased numbers of pedicle screws (low screw density) have no effects on the clinical outcomes for patients with Lenke 1 AIS. However, no previous studies have investigated the effects of reduced density of screw implantation on coronal correction and sagittal lumbar lordosis in patients with Lenke 5 AIS. METHODS Thirty-nine consecutive patients with Lenke 5 AIS underwent single-stage posterior correction and instrumented spinal fusion with pedicle screw fixation between 2006 and 2010. The radiographs were analyzed before surgery, immediately after surgery, and at the 2-year follow-up. General information of patients was recorded. Pearson correlation analysis was used to analyze the correlation between implant density, coronal Cobb angle correction, and correction index (postoperative correction/preoperative curve flexibility). The relations between implant density and magnitude of coronal and sagittal curve correction were also investigated. RESULTS The mean patient age at the time of operation was 14.5 years. The mean preoperative lumbar curve of 48.5° ± 9.2° was corrected to 13.7° ± 7.2° (72% correction) at a 2-year follow-up. There was a significant correlation between implant density and curve correction (r = 0.43, P < 0.05). No correlation was detected between implant density and correction index (r = -0.21, P = 0.20), and there was also no correlation between implant density and magnitude of sagittal curve correction (r = 0.065, P = 0.693). CONCLUSION Without curve flexibility taken into consideration, implant density is positively correlated with thoracolumbar or lumbar coronal Cobb curve correction. No significant correlation is found between screw density and correction index, if the effect of the flexibility was eliminated. There was no association between implant density and magnitude of sagittal curve correction before and after surgery.

Automatic cobb angle determination from radiographic images

Abstract: Study Design. Automatic measurement of Cobb angle in patients with scoliosis. Objective. To test the accuracy of an automatic Cobb angle determination method from frontal radiographical images. Summary of Background Data. Thirty-six frontal radiographical images of patients with scoliosis. Methods. A modified charged particle model is used to determine the curvature on radiographical spinal images. Three curve fitting methods, piece-wise linear, splines, and polynomials, each with 3 variants were used and evaluated for the best fit. The Cobb angle was calculated out of these curve fit lines and compared with a manually determined Cobb angle. The best-automated method is determined on the basis of the lowest mean absolute error and standard deviation, and the highest R2. Results. The error of the manual Cobb angle determination among the 3 observers, determined as the mean of the standard deviations of all sets of measurements, was 3.37°. For the automatic method, the best piece-wise linear method is the 3-segments method. The best spline method is the 10-steps method. The best polynomial method is poly 6. Overall, the best automatic methods are the piece-wise linear method using 3 segments and the polynomial method using poly 6, with a mean absolute error of 4,26° and 3,91° a standard deviation of 3,44° and 3,60°, and a R2 of 0.9124 and 0.9175. The standard measurement error is significantly lower than the upper bound found in the literature (11.8°). Conclusion. The automatic Cobb angle method seemed to be better than the manual methods described in the literature. The piece-wise linear method using 3 segments and the polynomial method using poly 6 yield the 2 best results because the mean absolute error, standard deviation, and R2 are the best of all methods.

Do multilevel Ponte osteotomies in thoracic idiopathic scoliosis surgery improve curve correction and restore thoracic kyphosis

Abstract: BACKGROUND To compare the routine use of posterior-based (Ponte) osteotomies to complete inferior facetectomies in thoracic idiopathic scoliosis. Hypokyphosis is common in thoracic adolescent idiopathic scoliosis. The use of pedicle screw fixation in deformity correction can exacerbate this hypokyphosis. We hypothesized that by utilizing posterior-based Ponte osteotomies rather than facetectomies, we could improve coronal plane correction and decrease the loss of kyphosis during curve correction. METHODS The radiographs and clinical charts of patients with idiopathic scoliosis (Lenke types I, II) who underwent isolated thoracic posterior spinal fusion utilizing primarily pedicle screw constructs from January 2008 to August 2010 were reviewed. Maximum preoperative Cobb angle, thoracic kyphosis (T5-T12), levels instrumented, number of posterior-based osteotomies, operative time, estimated blood loss, and postoperative residual coronal Cobb angle and kyphosis were recorded. Operative time per level, blood loss per level, percent main curve correction, and change in thoracic kyphosis was calculated. Patients having undergone complete inferior facetectomies and those with multilevel Ponte osteotomies were then compared. RESULTS Eighteen patients underwent posterior spinal fusion with osteotomies and 19 patients had complete inferior facetectomies during this time period. The osteotomy cohort had a larger preoperative Cobb angle [59±10 vs. 52±8 (mean±SD); P=0.03]. No difference was observed in the preoperative kyphosis (22±15 vs. 25±12) or in levels fused (9±1 vs. 8±1). Patients with routine osteotomies had them performed at 76% of the levels instrumented. No significant difference was found in terms of percentage of coronal plane correction (84% in both groups), average postoperative kyphosis 28±8 versus 25±7, or the change in kyphosis 6±14 versus 0±2 degrees, in the osteotomy and the facetectomy groups, respectively. Estimated blood loss per level was significantly higher in the osteotomy group (97±42 mL vs. 66±25 mL; P=0.01) as was time per level 31±5 versus 23±3 minutes/level (P<0.001). CONCLUSIONS This study shows a significantly higher blood loss and operative time associated with the use of routine posterior osteotomies in the thoracic spine without a significant improvement in coronal or sagittal correction.

Lowest instrumented vertebra selection for Lenke 5C scoliosis: a minimum 2-year radiographical follow-up.

Abstract: Study design A radiographical follow-up and analysis. Objective To investigate the postoperative curve change in Lenke 5C scoliosis, and to discuss how to select lowest instrumented vertebra (LIV). Summary of background data 5C curves are relatively rare in adolescent idiopathic scoliosis, and few studies have focused on this type of adolescent idiopathic scoliosis. Such questions as "How does the curve change over time in the postoperative period?" "Is LIV selection correlated with final correction and balance?" and "How should we select LIV for Lenke 5C curves?" need to be answered. Methods We reviewed all the adolescent idiopathic scoliosis cases surgically treated in an institution from 2002 through 2008. Inclusion criteria were as follows: (1) patients with Lenke 5C curves who were treated with selective lumbar fusion; (2) minimum 2-year radiographical follow-up.All image data were available and all measurements were performed in picture archiving and communication systems. Standing posteroanterior and lateral digital radiographs were reviewed at 4 junctures: preoperative, immediate postoperative, 3 months, and 2 years postoperatively. Results Thirty patients met the inclusion criteria. The following results were observed: (1) From the perspectives of both Cobb angle and vertebral translation, significant correction was achieved; (2) The correction obtained by surgery was well retained in the postoperative period; (3) Although preoperative spinal imbalance was common in this group of patients, the majority eventually attained balance at 2 years; (4) LIV selection was significantly correlated with the 2-year correction and balance; (5) In the literature as well as in this study, the overall preoperative LIV-center sacral vertical line distance is 28 mm and the overall preoperative LIV tilt is 25°. Conclusion In Lenke 5C scoliosis, preoperative spinal imbalance is common, although the majority of patients attain balance at 2 years. Significant correction loss is not common in the postoperative period. LIV selection significantly correlates with 2-year correction and balance. A translation of 28 mm and a tilt of 25° may be used as a general criterion for selecting LIV. Level of evidence 2.

Surgical treatment of Lenke 1 main thoracic idiopathic scoliosis: results of a prospective, multicenter study.

Abstract: Study design Prospective, consecutive, nonrandomized, multicenter study. Objective The purpose of this study was to compare the outcomes of idiopathic scoliosis treatment for Lenke 1 curves with 3 treatment approaches. Summary of background data Surgical treatment options for Lenke 1 or primary main thoracic curve pattern in adolescent idiopathic scoliosis include thoracoscopic anterior spinal fusion, open anterior spinal fusion, and posterior spinal fusion (PSF) and instrumentation procedures. Methods This was a prospective, consecutive, nonrandomized, multicenter study of surgical correction in adolescent idiopathic scoliosis. Patients with Lenke type 1 curve patterns from 7 sites were enrolled in this minimum 2-year follow-up study. Changes in pre- to postoperative radiographs, pulmonary function tests, Scoliosis Research Society questionnaire scores, and trunk rotation measures were compared. Results A total of 149 patients (age: 14.5 ± 2 yr) were included (91% follow-up at 2 yr). The 3 groups were similar preoperatively in thoracic and lumbar curve size. There were 55 patients with thoracoscopic anterior spinal fusion, 17 patients with open anterior spinal fusion, and 64 patients with PSF. The fusion included on average 3 to 4 more levels in PSF than the 2 anterior approaches (P ≤ 0.001). Surgical time tended to be greater in the anterior groups by approximately 2 to 3 hours; however, blood loss was greatest with PSF. At 2 years, all 3 approaches showed similar improvements in the thoracic Cobb angle, coronal balance, the lumbar Cobb angle, Scoliosis Research Society questionnaire scores, and trunk rotation measures. The PSF approach resulted in overall reduction in kyphosis compared with the anterior approaches. Postoperative hyperkyphosis was an issue only in the 2 anterior groups. Major complication rates were similar. Conclusion All 3 approaches resulted in similarly satisfactory outcomes for the majority of patients with specific advantages to each technique. The patients with PSF had more levels fused, yet with the shortest operative time. The thoracoscopic anterior spinal fusion group had the smallest incisions and the lowest requirement for transfusion. The open anterior spinal fusion group had a modest loss of pulmonary function without any clear advantages compared with the other 2 groups. Level of evidence 2.

Ponte Osteotomies With Pedicle Screw Instrumentation in the Treatment of Adolescent Idiopathic Scoliosis

Abstract: Study design Review of prospective database. Objectives To report the results of Ponte osteotomy with pedicle screw instrumentation for major thoracic adolescent idiopathic (AIS) curves. Summary of background data Ponte osteotomy for achieving coronal and sagittal correction of major thoracic curves in AIS with pedicle screw instrumentation is a widespread technique, but results have not been well described. Methods Review of 87 consecutive AIS patients with Lenke 1–4 curves who underwent Ponte osteotomies and pedicle screw instrumentation by 2 surgeons at a single institution. Surgical details, blood loss, and complications were recorded. We evaluated coronal and sagittal radiological measurements and Scoliosis Research Society–22 (SRS-22) questionnaire scores over 2-year follow-up. Results The mean preoperative thoracic coronal Cobb angle was 57° ± 9.7°, fulcrum flexibility was 47.2%, and lateral Cobb angle was 17.8° ± 4°. The mean estimated blood loss (EBL), expressed as percent estimated blood volume, was 35.8 ± 20.5 mL. There was significant improvement in coronal thoracic Cobb angle, percent correction, and apical vertebral translation over 2-year follow-up (p Conclusions In this case series of major thoracic AIS curves treated with segmental pedicle screw instrumentation and Ponte osteotomies, there was an improvement in the coronal and sagittal radiological parameters. A prospective controlled study is needed to determine whether pedicle screw instrumentation and Ponte osteotomies influence outcomes and complications.

Supine magnetic resonance imaging Cobb measurements for idiopathic scoliosis are linearly related to measurements from standing plain radiographs.

Abstract: STUDY DESIGN Retrospective OBJECTIVE To demonstrate a relationship between adolescent idiopathic scoliosis Cobb angle measurements obtained with standing plain radiographs and standard supine magnetic resonance (MR) images SUMMARY OF BACKGROUND DATA Patients with adolescent idiopathic scoliosis are exposed to repeated doses of ionizing radiation during the course of their treatment with significant potential long-term health consequences Supine MR images of the spine may allow measurements of coronal plane spinal deformity equivalent to plain radiographs while minimizing exposure to ionizing radiation METHODS A retrospective chart and radiograph review was conducted for patients with adolescent idiopathic scoliosis Cobb angle measures were derived from available plain radiographs and MR images obtained within 6 months of each other Pearson correlation and linear regression analysis was used to test the relationship between plain radiographical and magnetic resonance imaging Cobb measures Inter- and intraobserver reliability for the Cobb measures was tested with a random sample of 20 patients using intraclass correlation coefficients RESULTS Supine MR images tended to underestimate plain radiographs by 10° on average However, radiographical and MR measures showed a strong positive correlation (r= 090-094) for all curves, structural or nonstructural, and this correlation was not influenced by patient age or body mass index The relationship allowed the development of a simple linear equation for converting MR image measures to radiograph measures with an acceptable absolute error of ±5° CONCLUSION Cobb angle measures from supine magnetic resonance imaging of the spine can reliably be translated to the equivalent radiographical measures with an acceptable range of error The data suggest that standard supine magnetic resonance imaging sequences may be a viable substitute for plain radiographs in the clinical diagnosis and serial evaluation of adolescent idiopathic scoliosis while obviating the associated dangers of ionizing radiation from plain radiographs LEVEL OF EVIDENCE 3

Long-term outcomes of anterior dual-rod instrumentation for thoracolumbar and lumbar curves in adolescent idiopathic scoliosis: a twelve to twenty-three-year follow-up study.

Abstract: Background: Anterior spinal fusion with instrumentation is used for the treatment of thoracolumbar/lumbar scoliosis. The aim of this long-term, retrospective, hospital-based cohort study was to determine the outcomes of anterior dual-rod instrumentation in a consecutive series of patients with thoracolumbar/lumbar adolescent idiopathic scoliosis managed by a single surgeon at a single institution. Methods: A consecutive series of thirty-two patients with Lenke type-5C thoracolumbar/lumbar adolescent idiopathic scoliosis were included. Outcome measures included patient demographics, radiographic measurements, adjacent-segment degeneration, pulmonary function, and Scoliosis Research Society outcome instrument (SRS-30) scores. Perioperative and postoperative complications were recorded. Results: Thirty patients were followed for a mean of 17.2 years (range, twelve to twenty-three years). The mean thoracolumbar/lumbar Cobb angle correction rate and correction loss at the time of the latest follow-up were 79.8% and 3.4°, respectively. The average percent-predicted forced vital capacity and forced expiratory volume in one second were 91.8% and 81.8%, respectively. The average total SRS-30 score was 4.2. Mild degeneration below the fusion mass was observed in 23% of the patients. No instrumentation failure, pseudarthrosis, surgical site infection, or clinically relevant neurovascular complications were observed. Two patients required surgical revision with posterior spinal instrumentation, one because of subjacent disc wedging and the other because of progression of the thoracic curve deformity. Conclusions: Radiographic findings, pulmonary function, and clinical measures were satisfactory at the time of follow-up, at a minimum of twelve years. Anterior dual-rod instrumentation remains a useful surgical treatment for Lenke type-5C thoracolumbar/lumbar adolescent idiopathic scoliosis. Level of Evidence: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

VEPTR to treat nonsyndromic congenital scoliosis: A multicenter, mid-term follow-up study

Abstract: Background Traditional surgical management of multiple congenital vertebral anomalies in young children, including fusion in situ and hemiepiphyseodesis, do not promote spinal growth nor address the associated thoracic insufficiency syndrome. We hypothesize that vertical expandable prosthetic titanium rib (VEPTR) with expansion thoracoplasty may control spinal deformity, allow spinal growth, and address thoracic insufficiency syndrome in children with nonsyndromic complex congenital spinal deformities. Methods Eight pediatric spine centers prospectively entered clinical and radiographic data into a database on every congenital spinal deformity treated with VEPTR as part of an Food and Drug Administration study. We retrospectively reviewed these data and excluded patients with spina bifida, Jarcho-Levin, or other syndromes. Data analysis focused on surgical technique and expansion frequency, change in Cobb angle and thoracic heights, and adverse events for a consecutive series of patients with at least 2 years of follow-up. Results Twenty-four children with an average age at surgery of 3.3 years (range, 1.0 to 12.5 y) were treated with VEPTR insertion and expansion thoracostomy and were followed for an average of 40.7 months (range, 25 to 78 mo). Twenty-three (95.8%) had associated rib fusions. All patients had subsequent expansion surgery; 50% had 5 or more expansions. Twenty patients (83.3%) had an improvement in Cobb angle during treatment with an average improvement of 8.9 degrees. All had an increase in thoracic height, with a mean increase of 3.41 cm. The most common adverse events were device migration in 7 patients and infection or skin problems in 6 patients. Conclusions VEPTR insertion with expansion thoracoplasty represents a successful treatment paradigm for nonsyndromic congenital spinal deformities. We report multicenter data with midterm follow-up of children without syndromic diagnoses, in which the vast majority had an improvement in Cobb angle and thoracic height over the treatment period. Challenges include the demands of multiple procedures, skin problems, and device migration. Level of evidence Level IV-prognostic study.

Radiographical predictors for postoperative sagittal imbalance in patients with thoracolumbar kyphosis secondary to ankylosing spondylitis after lumbar pedicle subtraction osteotomy.

Abstract: STUDY DESIGN A retrospective radiographical study. OBJECTIVE To identify the radiographical predictors for sagittal imbalance in patients with thoracolumbar kyphosis secondary to ankylosing spondylitis (AS) after 1-level lumbar pedicle subtraction osteotomy (PSO). SUMMARY OF BACKGROUND DATA Few studies had correlated the preoperative sagittal parameters with postoperative sagittal alignments to determine the radiographical predictors for postoperative sagittal imbalance in patients with AS after 1-level lumbar PSO. METHODS Thirty-six patients with thoracolumbar kyphosis secondary to AS who underwent 1-level lumbar PSO were recruited with a minimal follow-up of 24 months (mean = 27.4 mo; range, 24-53 mo). Correlation analysis and subsequent stepwise multiple regression analysis were used to evaluate the correlations between preoperative parameters, including global kyphosis, local kyphosis, thoracic kyphosis, thoracolumbar Cobb angle, lumbar lordosis, pelvic incidence (PI), pelvic tilt, sacral slope, and sagittal vertical axis (SVA), as well as SVA at the last follow-up. All these patients were further divided into 2 groups according to the PI value (group A: PI >50°; group B: PI ≤50°). The correction outcomes were compared between these 2 groups. RESULTS The preoperative SVA was not significantly different between group A and group B (157.6 mm vs. 124.5 mm; P> 0.05), and both groups had similar magnitudes of kyphosis corrections at the last follow-up (global kyphosis: 42.9° vs. 46.1°; local kyphosis: 42.7° vs. 40.5°; lumbar lordosis: 35.7° vs. 43.0°). However, group A patients had significantly larger SVA at the last follow-up (73.2 mm vs. 28.7 mm; P< 0.05) and a higher incidence of postoperative sagittal imbalance (77.8% vs. 25.9%; P< 0.05) than those in group B. The stepwise multiple regression analysis demonstrated that both preoperative SVA and PI were significant independent predictors of postoperative sagittal alignments, which explained 52.0% and 9.7% of the variability of SVA at the last follow-up, respectively. CONCLUSION Patients with AS with either larger preoperative SVA or larger PI are more likely to experience failed sagittal realignments after 1-level lumbar PSO. For these patients, additional osteotomies may be recommended for satisfactory correction outcomes. LEVEL OF EVIDENCE 4.

Minimally invasive lateral approach for adult degenerative scoliosis: lessons learned.

Abstract: Object Lateral minimally invasive thoracolumbar instrumentation techniques are playing an increasing role in the treatment of adult degenerative scoliosis. However, there is a paucity of data in determining the ideal candidate for a lateral versus a traditional approach, and versus a hybrid construct. The objective of this study is to present a method for utilizing the lateral minimally invasive surgery (MIS) approach for adult spinal deformity, provide clinical outcomes to validate our experience, and determine the limitations of lateral MIS for adult degenerative scoliosis correction. Methods Radiographic and clinical data were collected for patients who underwent surgical correction of adult degenerative scoliosis between 2007 and 2012. Patients were retrospectively classified by degree of deformity based on coronal Cobb angle, central sacral vertical line (CSVL), pelvic incidence, lumbar lordosis (LL), sagittal vertical axis (SVA), pelvic tilt (PT), presence of comorbidities, bone quality, and curve f...

Clinical Results and Functional Outcomes of Primary and Revision Spinal Deformity Surgery in Adults

Abstract: Background Few studies have examined the postsurgical functional outcomes of adults with spinal deformities, and even fewer have focused on the functional results and complications among older adults who have undergone primary or revision surgery for spinal deformity. Our goal was to compare patient characteristics, surgical characteristics, duration of hospitalization, radiographic results, complications, and functional outcomes between adults forty years of age or older who had undergone primary surgery for spinal deformity and those who had undergone revision surgery for spinal deformity. Methods We retrospectively reviewed the cases of 167 consecutive patients forty years of age or older who had undergone surgery for spinal deformity performed by the senior author (K.M.K.) from January 2005 through June 2009 and who were followed for a minimum of two years. We divided the patients into two groups: primary surgery (fifty-nine patients) and revision surgery (108 patients). We compared the patient characteristics (number of levels arthrodesed, type of procedure, estimated blood loss, and total operative time), duration of hospitalization, radiographic results (preoperative, six-week postoperative, and most recent follow-up Cobb angle measurements for thoracic and lumbar curves, thoracic kyphosis, and lumbar lordosis), major and minor complications, and functional outcome scores (Scoliosis Research Society-22 Patient Questionnaire and Oswestry Disability Index). Results The groups were comparable with regard to most parameters. However, the revision group had more patients with sagittal plane imbalance and more frequently required pedicle subtraction osteotomies (p l 0.01). Patients in the primary group required more correction in the coronal plane than did patients in the revision group, whereas patients in the revision group required more correction in the sagittal plane. We found no significant difference between the two groups in the rate of major complications or in the Scoliosis Research Society-22 Patient Questionnaire functional outcome scores. There were significant improvements in many functional outcome scores in both groups between the preoperative and early (six-week) postoperative periods and between the early postoperative period and the time of final follow-up. Conclusions Revision surgery for spinal deformity in adults, although technically challenging and considered to present a higher risk than primary surgery, was shown to have a complication rate and outcomes that were comparable with those of primary spinal deformity surgery in adults. Level of evidence Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Selective thoracic fusion in Lenke 1C curves: prevalence and criteria.

Abstract: STUDY DESIGN Multicenter retrospective analysis of prospectively collected data. OBJECTIVE Evaluate radiographical and clinical characteristics of patients undergoing a selective thoracic fusion (STF) for Lenke 1C curves. SUMMARY OF BACKGROUND DATA STF of adolescent idiopathic scoliosis has been advocated for the so-called "false double major" curve (Lenke 1C/King type II). Despite these recommendations, many surgeons continue to perform nonselective fusions for this curve type. It is unknown to what extent other factors influence the surgeon's fusion-level selection. METHODS A prospective multicenter database included 264 patients with surgically treated Lenke 1C curves and were divided into 2 groups. The STF group included patients with the lowest instrumented vertebra at or cephalad to L1, whereas the nonselective fusion group included patients with the lowest instrumented vertebra at or caudal to L3. Preoperative radiographical, clinical (scoliometer), Scoliosis Appearance Questionnaire (SAQ), and Scoliosis Research Society (SRS) questionnaires were analyzed and compared. RESULTS Only 138 of 264 patients (49%) underwent an STF. Sex ratio (90% vs. 86% female), average age (14.7 vs. 14.8 yr), and preoperative main thoracic Cobb angles (56.0° ± 9.9° vs. 55.3° ± 11.4°) were not significantly different (STF vs. nonselective fusion). However, the average thoracolumbar/lumbar (TL/L) preoperative Cobb angle was significantly smaller in the STF group (42.1° ± 8.6° vs. 47.0° ± 9.0°; P < 0.001), whereas the main thoracic: TL/L Cobb ratio (1.35 ± 0.20 vs. 1.18 ± 0.15; P < 0.001), apical vertebral translation, and rotation (1.82 ± 0.59 vs. 1.31 ± 0.53; P < 0.001), (1.16 vs. 0.98; P < 0.001) ratios were significantly greater in the STF group. Preoperative coronal balance, sagittal Cobb angles (including T10-L2 kyphosis) and Risser Grade were not significantly different. Preoperative TL/L scoliometer measures were significantly less in the STF group (8.1° ± 3.7° vs. 10.3° ± 5.4°; P = 0.001). On the SAQ, the STF group had less desire for an appearance change. CONCLUSION Despite the recommendation to fuse only the structural thoracic curve in a 1C curve, only 49% of patients were treated with an STF. Those undergoing an STF had smaller TL/L Cobb angles, less TL/L clinical deformity, larger main thoracic: TL/L ratios, and less desire for an appearance change. LEVEL OF EVIDENCE 3.

Long-term outcomes of anterior spinal fusion for treating thoracic adolescent idiopathic scoliosis curves: average 15-year follow-up analysis.

Abstract: Study design Retrospective review. Objective To assess the long-term outcomes of anterior spinal fusion (ASF) for treating thoracic adolescent idiopathic scoliosis (AIS). Summary of background data Although ASF is reported to provide good coronal and sagittal correction of the main thoracic (MT) AIS curves, the long-term outcomes of ASF is unknown. Methods A consecutive series of 25 patients with Lenke 1 MT AIS were included. Outcome measures comprised radiographical measurements, pulmonary function, and Scoliosis Research Society outcome instrument (SRS-30) scores (preoperative SRS-30 scores were not documented). Postoperative surgical revisions and complications were recorded. Results Twenty-five patients were followed-up for 12 to 18 years (average, 15.2 yr). The average MT Cobb angle correction rate and the correction loss at the final follow-up were 56.7% and 9.2°, respectively. The average preoperative instrumented level of kyphosis was 8.3°, which significantly improved to 18.6° (P = 0.0003) at the final follow-up. The average percent-predicted forced vital capacity and forced expiratory volume in 1 second were significantly decreased during long-term follow-up measurements (73% and 69%; P = 0.0004 and 0.0016, respectively). However, no patient had complaints related to pulmonary function. The average total SRS-30 score was 4.0. Implant breakage was not observed. All patients, except 1 who required revision surgery, demonstrated solid fusion. Late instrumentation-related bronchial problems were observed in 1 patient who required implant removal and bronchial tube repair, 13 years after the initial surgery. Conclusion Overall radiographical findings and patient outcome measures of ASF for Lenke 1 MT AIS were satisfactory at an average follow-up of 15 years. ASF provides significant sagittal correction of the main thoracic curve with long-term maintenance of sagittal profiles. Percent-predicted values of forced vital capacity and forced expiratory volume in 1 second were decreased in this cohort; however, no patient had complaints related to pulmonary function.

A replication study for association of 53 single nucleotide polymorphisms in a scoliosis prognostic test with progression of adolescent idiopathic scoliosis in Japanese.

Abstract: Study design A genetic association study of single nucleotide polymorphisms (SNPs) previously reported to be associated with curve progression of adolescent idiopathic scoliosis (AIS). Objective To determine whether the association of 53 SNPs with curve progression reported in white patients with AIS are replicated in Japanese patients with AIS. Summary of background data Predicting curve progression is important in clinical practice of AIS. The progression of AIS is reported to be associated with a number of genes. Associations with 53 SNPs have been reported, and the SNPs are used for a progression test in white patients with AIS; however, there has been no replication study for their association. Methods We recruited 2117 patients with AIS with 10° or more (Cobb angle) of scoliosis curves. They were divided into progression and nonprogression groups according to their Cobb angle. We defined the progression of the curve as Cobb angle more than 50° for skeletally mature subjects and more than 40° for immature patients, subjects. We defined the nonprogression of the curve as Cobb angle 50° or less only for skeletally mature subjects. Of the 2117 patients, 1714 patients with AIS were allocated to either the progression or nonprogression group. We evaluated the association of 53 SNPs with curve progression by comparing risk allele frequencies between the 2 groups. Results We evaluated the progression (N = 600) and nonprogression (N = 1114) subjects. Their risk allele frequencies were not different significantly. We found no replication of the association on AIS curve progression in any of the SNPs. Conclusion The associations of the 53 SNPs with progression of AIS curve are not definite. Large-scale association studies based on appropriate criteria for progression would be necessary to identify SNPs associated with the curve progression. Level of evidence N/A.

Posterior decompression and short segmental pedicle screw fixation combined with vertebroplasty for Kümmell's disease with neurological deficits.

Abstract: The aim of this study was to investigate the treatment of Kummell’s disease with neurological deficits and to determine whether intravertebral clefts are a pathognomonic sign of Kummell’s disease. A total of 17 patients who had initially been diagnosed with Kummell’s disease were admitted, one patient was excluded from this study. Posterior decompression and vertebroplasty for the affected vertebrae were conducted. Pedicle screw fixation and posterolateral bone grafts were performed one level above and one level below the affected vertebrae. Vertebral tissue was extracted for histopathological examination. The mean time of follow-up was 22 months (range, 18 to 42 months). The anterior and middle vertebral heights were measured on standing lateral radiographs prior to surgery, one day postoperatively and at final follow-up. The Cobb angle, the visual analog scale (VAS) and the Frankel classification were used to evaluate the effects of the surgery. The VAS, anterior and middle vertebral heights and the Cobb angle were improved significantly one day postoperatively and at the final follow-up compared with the preoperative examinations (P 0.05). The neurological function of all patients was improved by at least one Frankel grade. All patients in this study exhibited intravertebral clefts, and postoperative pathology revealed bone necrosis. One patient (not included in this study) showed an intravertebral cleft, but the pathology report indicated a non-Hodgkin’s lymphoma. The intravertebral cleft sign is not pathognomonic of Kummell’s disease. Posterior decompression with short-segment fixation and fusion combined with vertebroplasty is an effective treatment for Kummell’s disease with neurological deficits.