Showing papers in "Spine in 2020"

Incidence of Surgical Site Infection After Spine Surgery: A Systematic Review and Meta-analysis.

Abstract: Study design A systematic review and meta-analysis. Objective The objective of this study was to investigate the incidence of surgical site infection (SSI) in patients following spine surgery and the rate of microorganisms in these cases. Summary of background data Many studies have investigated the incidence and risk factors of SSI following spinal surgery, whereas no meta-analysis studies have been conducted regarding the comprehensive epidemiological incidence of SSI after spine surgery. Methods We searched the PubMed, Embase, and Cochrane Library databases for relevant studies that reported the incidence of SSI after spine surgery, and manually screened reference lists for additional studies. Relevant incidence estimates were calculated. Subgroup analysis, sensitivity analysis, and publication bias assessment were also performed. Results Our meta-analysis included 27 studies, with 603 SSI cases in 22,475 patients. The pooled SSI incidence was 3.1%. Subgroup analysis revealed that the incidence of superficial SSI was 1.4% and the incidence of deep SSI was 1.7%. Highest incidence (13.0%) was found in patients with neuromuscular scoliosis among the different indications. The incidences of SSI in cervical, thoracic, and lumbar spine were 3.4%, 3.7%, and 2.7%, respectively. Compared with posterior approach surgery (5.0%), anterior approach showed a lower incidence (2.3%) of SSI. Instrumented surgery had a higher incidence of SSI than noninstrumented surgery (4.4% vs. 1.4%). Patients with minimally invasive surgery (1.5%) had a lower SSI incidence than open surgery (3.8%). Lower incidence of SSI was found when vancomycin powder was applied locally during the surgery (1.9%) compared with those not used (4.8%). In addition, the rates of Staphylococcus aureus, Staphylococcus epidermidis, and methicillin-resistant Staphylococci in microbiological culture results were 37.9%, 22.7%, and 23.1%, respectively. Conclusion The pooled incidence of SSI following spine surgery was 3.1%. These figures may be useful in the estimation of the probability of SSI following spine surgery. Level of evidence 3.

Accuracy of Pedicle Screw Placement and Clinical Outcomes of Robot-assisted Technique Versus Conventional Freehand Technique in Spine Surgery From Nine Randomized Controlled Trials: A Meta-analysis.

Abstract: Study design A meta-analysis. Objective To investigate whether robot-assisted techniques are superior to conventional techniques in terms of the accuracy of pedicle screw placement and clinical indexes. Summary of background data Robot-assisted techniques are increasingly applied to spine surgery to reduce the rate of screw misplacement. However, controversy about the superiority of robot-assisted techniques over conventional freehand techniques remains. Methods We conducted a comprehensive search of PubMed, EMBASE, and Cochrane Library for potentially eligible articles. The outcomes were evaluated in terms of risk ratio (RR) or standardized mean difference and the associated 95% confidence intervals (CIs). Meta-analysis was performed using the RevMan 5.3 software and subgroup analyses were performed based on the robot type for the accuracy of pedicle screw placement. Results Nine randomized controlled trials with 696 patients were included in this meta-analysis. The results demonstrated that the robot-assisted technique was more accurate in pedicle screw placement than the freehand technique. Subgroup analyses showed that the TINAVI robot-assisted technique was more accurate in screw positions Grade A (RR, 1.10; 95% CI, 1.06-1.14), Grade B (RR, 0.46; 95% CI, 0.28-0.75), and Grades C + D + E (RR, 0.21; 95% CI, 0.09-0.45) than the freehand technique, whereas the Renaissance robot-assisted technique showed the same accuracy as the freehand technique in screw positions Grade A, Grade B, and Grades C + D + E. Furthermore, the robot-assisted techniques showed equivalent postoperative stay, visual analogue scale scores, and Oswestry disability index scores to those of the freehand technique and shorter intraoperative radiation exposure time, fewer radiation dose and proximal facet violations but longer surgical time than the freehand technique. Conclusion The robot-assisted technique is more accurate in pedicle screw placement than the freehand technique. And TINAVI robot-assisted pedicle screw placement is a more accurate alternative to conventional techniques and the Renaissance robot-assisted procedure. Level of evidence 1.

Mechanical Aspects of Intervertebral Disc Injury and Implications on Biomechanics.

Abstract: Study design This article comprises a review of the literature. Objective The purpose of this study was to elucidate the different types of structural failures exhibited in intervertebral discs (IVDs), summarize their potential causes with respect to mechanical loading conditions and the consequences on cell homeostasis and biomechanics. Summary of background data Many studies have been performed to gain insight into how discogenic back pain progresses in humans both in vitro and in vivo as well as in animal disc models. However, there is a major need to summarize the common factors which initiate the structural failures observed in IVDs and the typical biomechanical changes. This work could help in developing mechanisms aiming to restore the biochemical and biomechanical balance of IVDs. Methods The different types of structural failures encountered in IVDs were reviewed from published literature. The types of mechanical loading causing these injuries and their physiological and biomechanical consequences were then summarized and linked to ongoing research in this area. Results The most prominent structural failures associated with IVDs are annulus tears, disc prolapse, endplate damage, disc narrowing, radial bulging, and osteophyte formation in the vertebrae. IVDs were found to be vulnerable to compression, flexion, axial rotation, and complex loading mechanisms through single impact, cyclical, and continuous loading. However, chronic loadings had a more damaging impact on the spine. Significant consequences include imbalance of metabolic enzymes and growth factors, alteration in stress profiles of IVDs and a decrease in mechanical stiffness resulting in impaired biomechanics of the spine. Conclusion The mode of loading has an important impact on the severity and nature of failures seen in IVDs and the resulting consequences to biomechanics. However, further research is necessary to better understand to the mechanisms that link injury to degeneration and regeneration of IVD tissues. Level of evidence 3.

Effective Prevention of Proximal Junctional Failure in Adult Spinal Deformity Surgery Requires a Combination of Surgical Implant Prophylaxis and Avoidance of Sagittal Alignment Overcorrection.

Abstract: STUDY DESIGN Propensity score matched analysis of a multi-center prospective adult spinal deformity (ASD) database. OBJECTIVE Evaluate if surgical implant prophylaxis combined with avoidance of sagittal overcorrection more effectively prevents proximal junctional failure (PJF) than use of surgical implants alone. SUMMARY OF BACKGROUND DATA PJF is a severe form of proximal junctional kyphosis (PJK). Efforts to prevent PJF have focused on use of surgical implants. Less information exists on avoidance of overcorrection of age-adjusted sagittal alignment to prevent PJF. METHODS Surgically treated ASD patients (age ≥18 yrs; ≥5 levels fused, ≥1 year follow-up) enrolled into a prospective multi-center ASD database were propensity score matched (PSM) to control for risk factors for PJF. Patients evaluated for use of surgical implants to prevent PJF (IMPLANT) versus no implant prophylaxis (NONE), and categorized by the type of implant used (CEMENT, HOOK, TETHER). Postoperative sagittal alignment was evaluated for overcorrection of age-adjusted sagittal alignment (OVER) versus within sagittal parameters (ALIGN). Incidence of PJF was evaluated at minimum 1 year postop. RESULTS Six hundred twenty five of 834 eligible for study inclusion were evaluated. Following PSM to control for confounding variables, analysis demonstrated the incidence of PJF was lower for IMPLANT (n = 235; 10.6%) versus NONE (n = 390: 20.3%; P < 0.05). Use of transverse process hooks at the upper instrumented vertebra (HOOK; n = 115) had the lowest rate of PJF (7.0%) versus NONE (20.3%; P < 0.05). ALIGN (n = 246) had lower incidence of PJF than OVER (n = 379; 12.0% vs. 19.2%, respectively; P < 0.05). The combination of ALIGN-IMPLANT further reduced PJF rates (n = 81; 9.9%), while OVER-NONE had the highest rate of PJF (n = 225; 24.2%; P < 0.05). CONCLUSION Propensity score matched analysis of 625 ASD patients demonstrated use of surgical implants alone to prevent PJF was less effective than combining implants with avoidance of sagittal overcorrection. Patients that received no PJF implant prophylaxis and had sagittal overcorrection had the highest incidence of PJF. LEVEL OF EVIDENCE 3.

Augmented Reality Surgical Navigation in Spine Surgery to Minimize Staff Radiation Exposure.

Abstract: Study design Prospective observational study. Objective To assess staff and patient radiation exposure during augmented reality surgical navigation in spine surgery. Summary of background data Surgical navigation in combination with intraoperative three-dimensional imaging has been shown to significantly increase the clinical accuracy of pedicle screw placement. Although this technique may increase the total radiation exposure compared with fluoroscopy, the occupational exposure can be minimized, as navigation is radiation free and staff can be positioned behind protective shielding during three-dimensional imaging. The patient radiation exposure during treatment and verification of pedicle screw positions can also be reduced. Methods Twenty patients undergoing spine surgery with pedicle screw placement were included in the study. The staff radiation exposure was measured using real-time active personnel dosimeters and was further compared with measurements using a reference dosimeter attached to the C-arm (i.e., a worst-case staff exposure situation). The patient radiation exposures were recorded, and effective doses (ED) were determined. Results The average staff exposure per procedure was 0.21 ± 0.06 μSv. The average staff-to-reference dose ratio per procedure was 0.05% and decreased to less than 0.01% after a few procedures had been performed. The average patient ED was 15.8 ± 1.8 mSv which mainly correlated with the number of vertebrae treated and the number of cone-beam computed tomography acquisitions performed. A low-dose protocol used for the final 10 procedures yielded a 32% ED reduction per spinal level treated. Conclusion This study demonstrated significantly lower occupational doses compared with values reported in the literature. Real-time active personnel dosimeters contributed to a fast optimization and adoption of protective measures throughout the study. Even though our data include both cone-beam computed tomography for navigation planning and intraoperative screw placement verification, we find low patient radiation exposure levels compared with published data. Level of evidence 3.

Risk Factors of Cage Subsidence in Patients Received Minimally Invasive Transforaminal Lumbar Interbody Fusion.

Abstract: Study design A retrospective cohort study. Objective To determine the risk factors of cage subsidence in patients undergoing minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) and its correlation with patient-reported outcomes. Summary of background data Cage subsidence is among the cage-related complications after TLIF and may lead to poor outcomes. Few studies have addressed the incidence of cage subsidence in MI-TLIF. Methods This retrospective study of a prospectively collected database was conducted from October 2015 to October 2017. All patients received MI-TLIF with a minimum of 2-year follow-up. All levels were separated into the cage subsidence (CS group) and no cage subsidence (non-CS group) groups. Cage subsidence was evaluated using lateral radiographs and defined as more than 2 mm migration of the cage into the endplate of adjacent vertebral body. Patient demographics, perioperative details, and radiographic parameters were recorded. Cage-related parameters were cage height, cage insertion level, and cage position. Cage position was recorded using central point ration (CPR). Patient-reported outcome was analyzed using the Oswestry Disability Index (ODI) questionnaire and Visual Analog Scale (VAS) preoperatively and at 2 years postoperatively. Results Ninety-three patients (126 levels) were included. Mean age was 66.5 years with an average follow-up of 36.9 months. Overall incidence of cage subsidence was 34.1%. The CS group had significantly higher body mass index, less bone mineral density (BMD), shorter disc height, and higher CPR than the non-CS group. BMD, disc height, and CPR were significantly negatively correlated with depth of cage subsidence. ODI improvement was significantly lesser in the CS group than in the non-CS group. Fusion rate and complications were unrelated to cage subsidence. Conclusion The BMD, disc height, and cage position were the most significant risk factors that were negatively correlated with depth of cage subsidence. Placing a TLIF cage anteriorly if possible may reduce the risk of cage subsidence. Level of evidence 3.

Thoracoscopic Vertebral Body Tethering for Adolescent Idiopathic Scoliosis: Follow-up Curve Behavior According to Sanders Skeletal Maturity Staging.

Abstract: STUDY DESIGN Retrospective analysis of prospectively collected data. OBJECTIVE To report the follow-up curve behaviors in different Sanders staging groups. SUMMARY OF BACKGROUND DATA Vertebral body tethering (VBT) is a growth modulation technique that allows gradual spontaneous follow-up curve correction as the patient grows. There is a lack of scientific evidence regarding appropriate patient selection and timing of implantation. METHODS Patients were grouped into five as: Sanders 1, 2, 3, 4-5, and 6-7. Data were collected preoperatively, at the day before discharge, and at each follow-up. Outcome measures were pulmonary and mechanical complications, readmission, and reoperation rates. Demographic, perioperative, clinical, radiographic, and complication data were compared using Fisher-Freeman-Halton exact tests for categorical variables and Kruskal-Wallis tests for the continuous variables. RESULTS Thirty-one (29 F, 2 M) consecutive patients with a minimum of 12 months of follow-up were included. The mean age at surgery was 12.1 (10-14). The mean follow-up was 27.1 (12-62) months. The mean preoperative main thoracic curve magnitude was 47° ± 7.6°. For all curves, preoperative and first erect curve magnitudes, bending flexibility, and operative correction percentages were similar between groups (for all comparisons, P > 0.05). The median height gained during follow-up was different between groups (P < 0.001), which was reflected into median curve correction during follow-up. Total curve correction percentage was different between groups (P = 0.009). Four (12.9%) patients had pulmonary and six (19.4%) had mechanical complications. One (3.2%) patient required readmission and two (6.5%) required reoperation. Occurrence of pulmonary complications was similar in Sanders groups (P = 0.804), while mechanical complications and overcorrection was significantly higher in Sanders 2 patients (P = 0.002 and P = 0.018). CONCLUSION Follow-up curve behavior after VBT is different in patients having different Sanders stages. Sanders 2 patients experienced more overcorrection, thus timing and/or correction should be adjusted, since Sanders 3, 4, and 5 patients displayed a lesser risk of mechanical complications. LEVEL OF EVIDENCE 3.

Prevalence of Osteoporosis in Patients Undergoing Lumbar Fusion for Lumbar Degenerative Diseases: A Combination of DXA and Hounsfield Units.

Abstract: STUDY DESIGN Retrospective analysis. OBJECTIVE To investigate the prevalence of osteoporosis (OP) in patients undergoing lumbar fusion for lumbar degenerative diseases (LDD). SUMMARY OF BACKGROUND DATA OP is related to many complications after lumbar fusion for patients with LDD. There are sparse data on the prevalence of OP among this specific population. Moreover, LDD can falsely elevate the bone mineral density measured by dual energy x-ray absorptiometry (DXA), leading to unreliable diagnostic results. Computed tomography (CT) Hounsfield unit (HU) values can help identify osteoporotic patients undetected by DXA. METHODS A total of 479 patients aged≥50 years undergoing lumbar fusion for LDD were reviewed. The diagnosis of OP using DXA was based on World Health Organization criterion. The criterion for OP diagnosed on CT scan was the L1-HU value≤110. RESULTS The prevalence of OP diagnosed on lumbar DXA, hip DXA, and both was 32.4%, 19.6%, 39.7%, respectively. The females had higher prevalence of OP diagnosed on DXA (spine and hip) than males (48.9% vs. 27.1%, P < 0.001). In females but not males, the prevalence of OP significantly increased with age (females, 50-59: 28.0%, 60-69: 58.1%, ≥70: 78.8%, P < 0.001). Patients having primary diagnosis of degenerative lumbar scoliosis had the higher prevalence of OP than the rest patients (56.5% vs. 36.8%, P = 0.002). Among the 324 patients diagnosed with non-OP by lumbar DXA, the prevalence of OP diagnosed on CT scan was 25.9%, it increased with age and was also highest in patients with degenerative lumbar scoliosis. CONCLUSION OP was quite common among patients aged≥50 years undergoing lumbar fusion for LDD, especially for females aged≥60 years or patients having degenerative lumbar scoliosis. Older patients or patients having degenerative lumbar scoliosis are more likely to have unreliable lumbar T-scores. Measurements of HU values can help identify more osteoporotic patients in this population. LEVEL OF EVIDENCE 3.

The Economic and Social Burden of Low Back Pain in Spain: A National Assessment of the Economic and Social Impact of Low Back Pain in Spain.

Abstract: Study design Economic evaluation of the costs of low back pain (LBP) in Spain from a societal perspective, including direct and indirect costs, based on a national representative sample of the general population, the National Health Survey of 2017 (NHS 2017). Objective To estimate the costs attributable to LBP in Spain. Summary of background data LBP has a high prevalence and is associated with lower quality of life, functional status, and increased use of health services. Studies that assess the socio-economic burden of LBP from a general population perspective have not been published yet in Spain. Methods Data from NHS 2017 were used. Direct costs (consultations-general practitioner, specialist and emergency departments-, diagnostic tests, hospitalizations, physiotherapy, psychologist, and medication consumption) and indirect costs (absenteeism and presenteeism) were assessed. Multivariate models were obtained to determine the independent attributable effect of LBP in each variable. Costs were determined through existing regional healthcare services public data. Results Prevalence of LBP was 17.1% for men and 24.5% for women, and increased with age, low educational status, higher body mass index, and was associated with less physical activity, and lower self-perceived health. Multivariate analysis demonstrated that LBP was independently associated with a significant increase both in the utilization of all health services and on work day losses. Attributable costs of LBP were 8945.6 million euros, of which 74.5% implied indirect costs, representing overall 0.68% of Spanish Gross Domestic Product. Conclusion Spain is paying a heavy price for LBP, mostly associated with its significant impact on absenteeism and presenteeism, as well as a noteworthy effect on excess health services utilization. These findings underscore the need to address this considerable public health and social problem through interventions that address widely LBP and that have demonstrated to be cost-effective. Level of evidence 3.

Improved Accuracy of Cervical Spinal Surgery With Robot-Assisted Screw Insertion: A Prospective, Randomized, Controlled Study.

Abstract: STUDY DESIGN Prospective, randomized, controlled trial. OBJECTIVE To compare robot-assisted and conventional implantation techniques by evaluating the accuracy and safety of implanting screws in cervical vertebrae. SUMMARY OF BACKGROUND DATA Cervical spinal surgery is difficult and dangerous as screw misplacement might lead not only to decreased stability but also neurological, vascular, and visceral injuries. A new robot-assisted surgical procedure has been introduced to improve the accuracy of implant screw positioning. METHODS We randomly assigned 135 patients with newly diagnosed cervical spinal disease and who required screw fixation using either robot-assisted or conventional fluoroscopy-assisted cervical spinal surgery. The primary outcomes were the discrepancies between the planned trajectories and the actual screw positions. RESULTS Altogether, 127 patients underwent the assigned intervention (61 robot-assisted and 66 conventional fluoroscopy-assisted). The baseline characteristics including the screw types, were similar in the two groups. Altogether, 390 screws were planed and placed in the cervical vertebrae, and 94.9% were acceptable. The robot-assisted group had a better screw placement accuracy than the conventional fluoroscopy-assisted group with associated P values <0.001 (0.83 [0.44, 1.29] vs. 1.79 [1.41, 2.50] mm). The Gertzbein and Robbins scales also showed a significant difference between the two groups (P < 0.001). Furthermore, the robot-assisted group experienced significantly less blood loss during surgery than the conventional fluoroscopy-assisted group (200 [50, 375] vs. 350 [100, 500] mL; P = 0.002) and shorter length of stay after surgery (P = 0.021). These two groups did not differ significantly regarding the duration of the operation (P = 0.525). Neurological injury occurred in one case in the conventional fluoroscopy-assisted group. CONCLUSION The accuracy and clinical outcomes of cervical spinal surgery using the robot-assisted technique tended to be superior to those with the conventional fluoroscopy-assisted technique in this prospective, randomized, controlled trial. LEVEL OF EVIDENCE 2.

Diagnostic Delays Lead to Greater Disability in Degenerative Cervical Myelopathy and Represent a Health Inequality.

Abstract: STUDY DESIGN Online survey. OBJECTIVE This study seeks to quantify delays faced, determine demographics of patients most likely to face delay, and determine whether delays affect surgical management and outcomes. SUMMARY OF BACKGROUND DATA Patients report significant delays in diagnosis of degenerative cervical myelopathy (DCM). METHODS Seven hundred seventy-eighty patients with self-reported DCM recruited via online survey hosted on myelopathy.org. A cumulative odds ordinal logistic regression was run to determine the effects of demographic (sex, country of residence, ethnicity, household income, and educational status) on the delay in diagnosis of DCM. Chi-square tests of homogeneity were run to determine the effects of delayed diagnosis on functional outcomes (patient-derived modified Japanese Orthopaedic Association disability score, support dependence, and employment status) and surgical management (anterior/posterior approach, single-/multilevel surgery). A Kruskal-Wallis H test was used to determine whether delayed diagnosis affected the number of operations undergone. RESULTS The average delay in diagnosis faced was "1-2 years.' Greater delays in diagnosis were faced by Black or African American patients (P = 0.010). Delayed diagnosis was predictive of greater disability as assessed by patient-derived modified Japanese Orthopaedic Association score (P = 0.001), support dependence (P = 0.040), and employment status (P < 0.0005). Delayed diagnosis did not affect the likelihood of surgery, the number of operations undergone or perioperative characteristics. CONCLUSION Patients continue to face significant delays in diagnosis of DCM. Ethnicity significantly influences length of delay experienced. Longer delays do not appear to affect surgical management but are associated with greater disability. LEVEL OF EVIDENCE 3.

Does Lumbar Interbody Cage Size Influence Subsidence? A Biomechanical Study.

Abstract: Study Design.An experimental laboratory-based biomechanical study.Objective.To investigate the correlation between cage size and subsidence and to quantify the resistance to subsidence that a larger cage can provide.Summary of Background Data.The assumption that a bigger interbody cage confers less

A Review of Techniques, Time-demand, Radiation Exposure and Outcomes of Skin-anchored Intra-operative 3D Navigation in Minimally Invasive Lumbar Spinal Surgery

Abstract: STUDY DESIGN Retrospective cohort. OBJECTIVE To describe our technique for and evaluate the time demand, radiation exposure and outcomes of skin-anchored intraoperative three-dimensional navigation (ION) in minimally invasive (MIS) lumbar surgery, and to compare these parameters to 2D fluoroscopy for MI-TLIF. SUMMARY OF BACKGROUND DATA Limited visualization of anatomic landmarks and narrow access corridor in MIS procedures result in greater reliance on image guidance. Although two-dimensional fluoroscopy has historically been used, ION is gaining traction. METHODS Patients who underwent MIS lumbar microdiscectomy, laminectomy, or MI-TLIF using skin-anchored ION and MI-TLIF by the same surgeon using 2D fluoroscopy were selected. Operative variables, radiation exposure, and short-term outcomes of all procedures were summarized. Time-demand and radiation exposure of fluoroscopy and ION for MI-TLIF were compared. RESULTS Of the 326 patients included, 232 were in the ION cohort (92 microdiscectomies, 65 laminectomies, and 75 MI-TLIFs) and 94 in the MI-TLIF using 2D fluoroscopy cohort. Time for ION setup and image acquisition was a median of 22 to 24 minutes. Total fluoroscopy time was a median of 10 seconds for microdiscectomy, 9 for laminectomy, and 26 for MI-TLIF. Radiation dose was a median of 15.2 mGy for microdiscectomy, 16.6 for laminectomy, and 44.6 for MI-TLIF, of this, 93%, 95%, and 37% for microdiscectomy, laminectomy, and MI-TLIF, respectively were for ION image acquisition, with the rest attributable to the procedure. There were no wrong-level surgeries. Compared with fluoroscopy, ION for MI-TLIF resulted in lower operative times (92 vs. 108 min, P < 0.0001), fluoroscopy time (26 vs. 144 s, P < 0.0001), and radiation dose (44.6 vs. 63.1 mGy, P = 0.002), with equivalent time-demand and length of stay. ION lowered the radiation dose by 29% for patients and 55% for operating room personnel. CONCLUSION Skin-anchored ION does not increase time-demand compared with fluoroscopy, is feasible, safe and accurate, and results in low radiation exposure. LEVEL OF EVIDENCE 3.

Trends in Leadership at Spine Surgery Fellowships.

Abstract: STUDY DESIGN Cross-sectional study. OBJECTIVE To illustrate demographic trends among spine fellowship leaders (FLs). SUMMARY OF BACKGROUND DATA No previous study in the orthopedic literature has analyzed the demographic characteristics or past surgical training of FL in an orthopedic sub-specialty. We attempt to illustrate demographic trends among spine fellowship leadership including fellowship directors (FDs) and co-fellowship directors (co-FDs). We also highlight the institutions that have trained these leaders at various levels. METHODS Our search for FDs was constructed from the 2018 to 2019 North American Spine Surgery (NASS) Fellowship Directory. Datapoints gathered included: age, sex, residency/fellowship training location, time since training completion until FD appointment, length in FD role, and personal research H-index. RESULTS We identified 103 FLs consisting of 67 FDs, 19 co-FDs, and another 16 individuals with a synonymous leadership title. 96.1% (99) of the leadership consisted of males while 3.9% (4) were female. The mean age was 52.9 years old and the mean h-index of the FLs was 23.8. FLs were trained in orthopedic surgery (n = 89), neurosurgery (n = 13), or combined orthopedic surgery and neurosurgery training (n = 1). The top fellowships programs producing future FLs were: Case Western Reserve University, Cleveland (n = 10), Washington University, St. Louis (n = 9), and Rothman Orthopaedic Institute, Thomas Jefferson University, Philadelphia (n = 7). CONCLUSION Spine surgery fellowship directors are more likely to have graduated from certain residency and fellowship programs. This finding could be a result of the training provided by these centers or the institution's predilection to select applicants that are more likely to later seek academic leadership roles post-training. LEVEL OF EVIDENCE 4.

Indirect Decompression Effect to Central Canal and Ligamentum Flavum After Extreme Lateral Lumbar Interbody Fusion (XLIF) and Oblique Lumbar Interbody Fusion (OLIF).

Abstract: STUDY DESIGN A retrospective study (level of evidence: level 4). OBJECTIVE To evaluate the radiographic outcomes after extreme lateral lumbar interbody fusion (XLIF) and oblique lateral lumbar interbody fusion (OLIF) procedures especially the effect of indirect decompression to the ligamentum flavum and to evaluate the effect of facet degeneration to the radiographic outcomes of these procedures. SUMMARY OF BACKGROUND DATA Indirect decompression via lateral lumbar interbody fusion provides spinal canal area expansion. However, the effect to the ligamentum flavum area and thickness at the operated spinal level is unclear. METHODS Thirty-five patients (57 lumbar levels) underwent XLIF or OLIF with percutaneous pedicle screw fixation (PPS) without direct posterior decompression were retrospectively studied. Radiographic parameters including ligamentum flavum area (LFA), ligamentum flavum thickness (LFT), cross-sectional area (CSA) of thecal sac, posterior disc height, foraminal height, cage alignment, and facet degeneration were measured on magnetic resonance image (MRI). Cage position was assessed with plain radiography. RESULTS All of the radiographic parameters were significantly improved. Comparing pre- and postoperative value, mean LFA decreased from 78.9 ± 24.9 mm to 66.9 ± 26.8 mm (-14.2%; P-value < 0.00625). Mean right LFT decreased from 2.9 ± 0.9 mm to 2.3 ± 0.7 (-17.0%; P-value < 0.00625). Mean left LFT decreased from 3.3 ± 1.6 mm to 2.6 ± 0.9 mm (-17.6%; P-value < 0.00625). Mean CSA of thecal sac increased from 93.1 ± 43.0 mm to 127.3 ± 52.5 mm (50.8%; P-value < 0.00625). All radiographic outcomes were not significant difference between lumbar levels that have grade 0-1 and grade 2-3 or between grade 2 and grade 3 facet degeneration. CONCLUSION Ligamentum flavum area and thickness were significantly reduced after lateral lumbar interbody fusion through both XLIF and OLIF. Unbuckling of the ligamentum flavum played an important role for improvement of spinal canal area after the indirect decompression. LEVEL OF EVIDENCE 4.

Percutaneous Transforaminal Endoscopic Discectomy Versus Microendoscopic Discectomy for Lumbar Disc Herniation: Two-Year Results of a Randomized Controlled Trial.

Abstract: Study design A prospective randomized controlled study. Objective To clarify whether percutaneous transforaminal endoscopic discectomy (PTED) has better clinical outcomes and less surgical trauma compared with microendoscopic discectomy (MED). Summary of background data Two kinds of minimally invasive spine surgeries, PTED and MED, are now widely used for the treatment of lumbar disc herniation (LDH). It is still a controversial issue to choose the proper surgical approach. Methods In this single-center, open-label, randomized controlled trial, patients were included if they had persistent signs and symptoms of radiculopathy with corresponding imaging-confirmed LDH, and were randomly allocated to PTED or MED group. The primary outcome was the score of Oswestry Disability Index (ODI) and the secondary outcomes included the score of Medical Outcomes Study 36-Item Short-Form Health Survey bodily pain and physical function scales, European Quality of Life-5 Dimensions, and Visual Analogue Scales for back pain and leg pain. Results A total of 250 participants were randomly assigned to two treatment groups, 241 of that received the specific surgical procedure. Two hundred twenty-two patients (92.1%) have completed the 2-year follow-up. Both the primary and secondary outcomes did not differ significantly between the two treatment groups at each prespecified follow-up time (P > 0.05). For PTED, the postoperative improvement of ODI score in the median herniation subgroup was less compared with paramedian subgroup. For MED, less improvement of ODI score was found in far-lateral herniation subgroup compared with paramedian subgroup. Total complication rate over the course of 2 year was 13.44% in PTED group and 15.57% in MED group (P = 0.639). Ten cases (8.40%) in PTED group and five cases (4.10%) in MED group suffered from residue/recurrence of herniation, for which reoperation was required. Conclusion Over the 2-year follow-up period, PTED did not show superior clinical outcomes and did not appear to be safer procedure for patients with LDH compared with MED. PTED had inferior results for median disc herniation, whereas MED did not appear to be the best option for far-lateral disc herniation. Level of evidence 2.

The Importance of C2-Slope, a Singular Marker of Cervical Deformity, Correlates with Patient Reported Outcomes

Abstract: STUDY DESIGN Retrospective review of a prospectively collected database. OBJECTIVE To define a simplified singular measure of cervical deformity (CD), C2 slope (C2S), which correlates with postoperative outcomes. SUMMARY OF BACKGROUND DATA Sagittal malalignment of the cervical spine, defined by the cervical sagittal vertical axis (cSVA) has been associated with poor outcomes following surgical correction of the deformity. There has been a proliferation of parameters to describe CD. This added complexity can lead to confusion in classifying, treating, and assessing outcomes of CD surgery. METHODS A prospective database of CD patients was analyzed. Inclusion criteria were cervical kyphosis>10°, cervical scoliosis>10°, cSVA>4 cm, or chin-brow vertical angle >25°. Patients were categorized into two groups and compared based on whether the apex of the deformity was in the cervical (C) or the cervicothoracic (CT) region. Radiographic parameters were correlated to C2S, T1 slope (T1S) and 1-year health-related quality-of-life outcomes as measured by the EuroQol 5 Dimension questionnaire (EQ5D), modified Japanese Orthopedic Association Scale, numeric rating scale for neck pain, and the Neck Disability Index (NDI). RESULTS One hundred four CD patients (C = 74, CT = 30; mean age 61 yr, 56% women, 42% revisions) were included. CT patients had higher baseline cSVA and T1S (P 0.5, P≤0.05). Using linear regression, moderate disability by EQ5D corresponded to C2S of 20°(r = 0.08). For CT patients, C2S = 17° corresponded to moderate disability by NDI (r = 0.4), and C2S = 20° by EQ5D (r = 0.25). CONCLUSION C2S correlated with upper-cervical and subaxial alignment. C2S correlated strongly with TS-CL (R = 0.98, P < 0.001) because C2S is a mathematical approximation of TS-CL. C2S is a useful marker of CD, linking the occipitocervical and cervico-thoracic spine. C2S defines the presence of a mismatch between cervical lordosis and thoracolumbar alignment. Worse 1-year postoperative C2 slope correlated with worse health outcomes. LEVEL OF EVIDENCE 3.

Global Trends of Researches on Sacral Fracture Surgery: A Bibliometric Study Based on VOSviewer.

Abstract: Study design Bibliometric analysis. Objective This study aims to identify and summarize the articles related to sacral fracture surgery, to compare the papers from different countries and journals, to show the trends of researches on sacral fracture surgery. Summary of background data In recent years, studies on sacral fracture are growing rapidly, but there were no bibliometric studies regarding sacral fracture surgery. Methods Excel 2016 and VOSviewer were used to identify and summarize the articles from Web of Science between 1900 and 2018. Publication number, publication year, publication country, publication organization, publication source, author, sum of times cited, H-index, and journal's impact factors were recorded and analyzed. Bibliometric maps of co-citations and maps of co-occurrence of keywords are drawn. Results A total of 611 publications were extracted. United States published most articles (227, 37.2%), both total citations (3536) and H-index (32) of United States ranked first of all the countries. The most productive organization on sacral fracture surgery is Johns Hopkins University (14). Spine (43) published the most articles on sacral fracture surgery. The latest keyword "patterns" appeared in 2017 in 5 articles. Other relatively new keywords include "proximal junctional kyphosis," "spondylopelvic dissociation," "fragility fracture," "lumbopelvic fixation" that appeared in 2017 in eight, six, six, and 25 articles, respectively. Conclusion This bibliometric study showed that there is a growing trend both in published articles related to sacral fracture surgery and relative research interest in the last 30 years. United States dominates the research regarding sacral fracture surgery. Johns Hopkins University, Johannes Gutenberg University of Mainz, and Harborview Medical Center are the best institutions related to sacral fracture surgery research. Spine, J Orthop Trauma, and Injury are the top three productive journals on sacral fracture surgery. Sacral fracture patterns, proximal junctional kyphosis, spondylopelvic dissociation, fragility fracture, and lumbopelvic fixation may be the new research hotspot in this field. Level of evidence 5.

2020 Young Investigator Award Winner: Age- and Sex-related Normative Value of Whole-body Sagittal Alignment Based on 584 Asymptomatic Chinese Adult Population From Age 20 to 89.

Abstract: Study Design.A cross-sectional radiographic study.Objective.The aim of this study was to establish the age- and sex-related normative values of whole-body sagittal alignment in asymptomatic Chinese adult population, and to investigate the changes and possible associated compensation mechanisms acros

Preoperative Factors Predict Postoperative Trajectories of Pain and Disability Following Surgery for Degenerative Lumbar Spinal Stenosis.

Abstract: Study Design. Longitudinal analysis of prospectively collected data. Objective. Investigate potential predictors of poor outcome following surgery for degenerative lumbar spinal stenosis (LSS). Summary of Background Data. LSS is the most common reason for an older person to undergo spinal surgery, yet little information is available to inform patient selection. Methods. We recruited LSS surgical candidates from 13 orthopedic and neurological surgery centers. Potential outcome predictors included demographic, health, clinical, and surgery-related variables. Outcome measures were leg and back numeric pain rating scales and Oswestry disability index scores obtained before surgery and after 3, 12, and 24 postoperative months. We classified surgical outcomes based on trajectories of leg pain and a composite measure of overall outcome (leg pain, back pain, and disability). Results. Data from 529 patients (mean [SD] age = 66.5 [9.1] yrs; 46% female) were included. In total, 36.1% and 27.6% of patients were classified as experiencing a poor leg pain outcome and overall outcome, respectively. For both outcomes, patients receiving compensation or with depression/depression risk were more likely, and patients participating in regular exercise were less likely to have poor outcomes. Lower health-related quality of life, previous spine surgery, and preoperative anticonvulsant medication use were associated with poor leg pain outcome. Patients with ASA scores more than two, greater preoperative disability, and longer pain duration or surgical waits were more likely to have a poor overall outcome. Patients who received preoperative chiropractic or physiotherapy treatment were less likely to report a poor overall outcome. Multivariable models demonstrated poor-to acceptable (leg pain) and excellent (overall outcome) discrimination. Conclusion. Approximately one in three patients with LSS experience a poor clinical outcome consistent with surgical non-response. Demographic, health, and clinical factors were more predictive of clinical outcome than surgery-related factors. These predictors may assist surgeons with patient selection and inform shared decision-making for patients with symptomatic LSS.

Association Between Modic Changes and Low Back Pain in Middle Age: A Northern Finland Birth Cohort Study.

Abstract: Study design A cross-sectional study of the Northern Finland Birth Cohort 1966 (NFBC1966). Objective The aim of this study was to evaluate the association between the type, size, and location of lumbar Modic changes (MC), and prolonged disabling low back pain (LBP). Summary of background data LBP is the leading cause of disability worldwide and it affects all age- and socioeconomical groups. Only a small proportion of LBP patients are diagnosed with a specific cause: In most cases no single nociceptive cause for the pain can be identified. MC are visualized in magnetic resonance imaging (MRI) as a signal intensity change in vertebral bone marrow and have been proposed to represent a specific degenerative imaging phenotype associated with LBP. MC can be classified into several subtypes, of which inflammatory Type 1 (MC1) is suggested as being more likely to be associated with LBP. Methods We assessed lumbar MRI (n = 1512) for the presence, type, and size of MC. The associations of MC characteristics with prolonged (≥30 days during the past year) and disabling (bothersomeness of LBP at least 6 on a 0-10 Numeric Rating Scale) LBP, evaluated at the time of imaging at 47 years, were analyzed using binary logistic regression, adjusted for sex, BMI, smoking, educational status, lumbar disc degeneration, and disc herniations. Results Any MC and MC1 were associated with prolonged disabling LBP (odds ratio [OR] after full adjustments 1.50 [95% confidence interval, CI 1.05-2.15] and 1.50 [95% CI 1.10-2.05], respectively). Furthermore, MC covering the whole anterior-posterior direction or the whole endplate, as well as the height of MC, were significantly associated with prolonged disabling LBP (OR after full adjustments 1.59 [95% CI 1.14-2.20], 1.67 [95% CI 1.13-2.46] and 1.26 [95% CI 1.13-1.42], respectively). Conclusion Our study showed a significant and independent association between MC and clinically relevant LBP. Level of evidence 3.

Validation of PROMIS Physical Function in MIS TLIF: 2-Year Follow-up.

Abstract: STUDY DESIGN Retrospective cohort. OBJECTIVE We evaluate the correlation of the Patient-Reported Outcomes Measurement Information System for physical function (PROMIS-PF) with legacy patient-reported outcome measures (PROMs) in patients undergoing minimally invasive transforaminal lumbar interbody fusion (MIS TLIF) up to 2 years postoperatively. SUMMARY OF BACKGROUND DATA PROMIS-PF has not been validated past 6 months following MIS TLIF. METHODS A surgical registry was retrospectively reviewed for eligible MIS TLIFs between May 2015 and September 2017. Inclusion criteria were primary, one- or two-level MIS TLIFs for degenerative spinal pathology. Patients without preoperative or 2-year follow up PROMIS-PF surveys were excluded. Demographic, perioperative, and PROMs including Visual Analog Scale (VAS) back, VAS leg, Oswestry Disability Index (ODI), 12-Item Short Form (SF-12) physical component summary (PCS) scores, and PROMIS-PF at preoperative and postoperative timepoint (e.g., 6 weeks, 12 weeks, 6 months, 1 year, and 2 years). A paired t test evaluated PROM improvement from baseline. The relationship of PROMIS-PF with VAS back, VAS leg, SF-12 PCS, and ODI was evaluated with a Pearson correlation coefficient. RESULTS The 68-subject cohort was 41.2% female, with an average age of 52.9 years; 44.1% were obese, and the majority underwent one-level fusions (95.6%). Pain (VAS back, VAS leg) and disability metrics (ODI) demonstrated significant improvement at all timepoints following MIS TLIF when compared to baseline (all P < 0.001). Physical function (SF-12 PCS, PROMIS-PF) demonstrated significant postoperative improvement at 12 weeks, 6 months, 1 year, and 2 years (all P < 0.001). All evaluated timepoints, with the exception of preoperative VAS back scores, revealed strong PROMIS-PF correlations with VAS back, VAS leg, ODI, and SF-12 PCS. CONCLUSION PROMIS-PF demonstrated a strong correlation with pain (VAS back, VAS leg), disability (ODI) and physical function (SF-12) at all postoperative follow-ups through 2 years. Our study provides longitudinal evidence for utilizing PROMIS-PF as a valid physical function measure among patients undergoing MIS TLIF. LEVEL OF EVIDENCE 4.

Asymptomatic ACDF Nonunions Underestimate the True Prevalence of Radiographic Pseudarthrosis

Abstract: Study design Secondary analysis of subjects in the control anterior cervical discectomy and fusion (ACDF) arm of Medtronic Investigational Device Exemption (IDE) trials for cervical disc arthroplasty (CDA). Objectives To compare patient-reported outcomes (PROs) in patients with radiographic nonunion to patients with a solid fusion. Summary of background data The true prevalence of nonunion after ACDF is unknown. Nonunion may be under-reported, as some patients are not symptomatic enough to justify radiographic evaluation. Methods Three hundred forty-five subjects enrolled in the control arm of IDE trials for CDA who had single-level ACDF with allograft and plate with 24 month data formed the study cohort. Using the 24-month postop evaluation, subjects were divided into those who had radiographic fusion and those who did not using strict study criteria. SF-36, NDI, Neck and Arm pain NRS scores were reported at 12, 24, 36, 60, and 84 months postop. For subjects who had secondary surgery failures, the last observations before the secondary surgery were carried forward to future visits for the analysis. Results Forty-four (13%) patients had radiographic nonunion and 301 (87%) were fused at 24 months postop. At 24 months, PROs were similar between the two groups. Seven patients in the Nonunion group (16%) and 10 (3%) in the Fused group had additional surgery at the index level prior to the 24 follow-up (P = 0.003). Over the 84-month follow-up a total of 9 patients in the Nonunion group (21%) and 22 (7%) in the Fused group had additional surgery at the index level (P = 0.009). Conclusion While the radiographic nonunion rate at 24 months was 13%, PROs show that many of the radiographic nonunions were asymptomatic. Although the majority of patients with radiographic nonunion did not undergo additional surgery, the rate of secondary surgeries at the index level was significantly higher in the radiographic nonunion group. Level of evidence 2.

Disparities in Outcomes by Insurance Payer Groups for Patients Undergoing Anterior Cervical Discectomy and Fusion.

Abstract: STUDY DESIGN Retrospective, observational study of clinical outcomes at a single institution. OBJECTIVE To compare postoperative complication and readmission rates of payer groups in a cohort of patients undergoing anterior cervical discectomy and fusion (ACDF). SUMMARY OF BACKGROUND DATA Studies examining associations between primary payer and outcomes in spine surgery have been equivocal. METHODS Patients at Mount Sinai having undergone ACDF from 2008 to 2016 were queried and assigned to one of five insurance categories: uninsured, managed care, commercial indemnity insurance, Medicare, and Medicaid, with patients in the commercial indemnity group serving as the reference cohort. Multivariable logistic regression equations for various outcomes with the exposure of payer were created, controlling for age, sex, American Society of Anesthesiology Physical Status Classification (ASA Class), the Elixhauser Comorbidity Index, and number of segments fused. A Bonferroni correction was utilized, such that alpha = 0.0125. RESULTS Two thousand three hundred eighty seven patients underwent ACDF during the time period. Both Medicare (P < 0.0001) and Medicaid (P < 0.0001) patients had higher comorbidity burdens than commercial patients when examining ASA Class. Managed care (2.86 vs. 2.72, P = 0.0009) and Medicare patients (2.99 vs. 2.72, P < 0.0001) had more segments fused on average than commercial patients. Medicaid patients had higher rates of prolonged extubation (odds ratio [OR]: 4.99; 95% confidence interval [CI]: 1.13-22.0; P = 0.007), and Medicare patients had higher rates of prolonged length of stay (LOS) (OR: 2.44, 95% CI: 1.13-5.27%, P = 0.004) than the commercial patients. Medicaid patients had higher rates of 30- (OR: 4.12; 95% CI: 1.43-11.93; P = 0.0009) and 90-day (OR: 3.28; 95% CI: 1.34-8.03; P = 0.0009) Emergency Department (ED) visits than the commercial patients, and managed care patients had higher rates of 30-day readmission (OR: 3.41; 95% CI: 1.00-11.57; P = 0.0123). CONCLUSION Medicare and Medicaid patients had higher rates of prolonged LOS and postoperative ED visits, respectively, compared with commercial patients. LEVEL OF EVIDENCE 3.

New Onset Depression and Anxiety After Spinal Fusion Surgery: Incidence and Risk Factors.

Abstract: STUDY DESIGN Retrospective database study. OBJECTIVE We sought to investigate trends and risk factors for new-onset anxiety and/or depression within 6 months after elective spine surgery. SUMMARY OF BACKGROUND DATA Surgery represents a stressful experience associated with a number of physiological and psychological consequences. A subset of patients develop clinically significant symptoms of new-onset anxiety or depression. However, the incidence of and risk factors for these adverse outcomes after spine surgery remain ill-defined. METHODS We performed a retrospective analysis including anterior cervical discectomy and fusion and posterior lumbar fusion cases from 2012 to 2015, utilizing the Truven MarketScan database. Primary outcomes were new-onset depression, new-onset anxiety, and new-onset depression and/or anxiety after surgery. Potential risk factors included patient demographics, comorbidities, hospital and procedural characteristics as well as perioperative opioid regimens. Multivariable logistic regression models measured associations between risk factors and outcomes. Odds ratios (OR) were reported and results with P < 0.0167 were considered statistically significant. RESULTS Among 39,495 unique patients, overall incidence of new-onset depression and anxiety was 6% and 11.2%, respectively. In adjusted analyses, significant risk factors across all three outcomes included chronic opioid use (ORs ranging from 1.31 to 2.93; P < 0.01), female sex (ORs ranging from 1.25 to 1.67; P < 0.01), longer length of stay (ORs ranging from 1.05 to 1.08; P < 0.01), and readmission within 6 months of surgery (OR ranging from 1.31 to 1.68; P < 0.01). CONCLUSION We identified several risk factors contributing to increased odds of new-onset depression and/or anxiety after spine fusion surgery. These data may aid the implementation of preventative measures among identified high-risk patients. LEVEL OF EVIDENCE 3.

Black Race as a Social Determinant of Health and Outcomes After Lumbar Spinal Fusion Surgery: A Multistate Analysis, 2007 to 2014.

Abstract: Study design A retrospective analysis of patient hospitalization and discharge records. Objective To examine the association between race and inpatient postoperative complications following lumbar spinal fusion surgery. Summary of background data Racial disparities in healthcare have been demonstrated across a range of surgical procedures. Previous research has identified race as a social determinant of health that impacts outcomes after lumbar spinal fusion surgery. However, these studies are limited in that they are outdated, contain data from a single institution, analyze small limited samples, and report limited outcomes. Our study aims to expand and update the literature examining the association between race and inpatient postoperative complications following lumbar spine surgery. Methods We analyzed 267,976 patient discharge records for inpatient lumbar spine surgery using data from the Healthcare Cost and Utilization Project's State Inpatient Databases for California, Florida, New York, Maryland, and Kentucky from 2007 through 2014. We used unadjusted bivariate analysis, adjusted multivariable, and stratified analysis to compare patient demographics, present-on-admission comorbidities, hospital characteristics, and complications by categories of race/ethnicity. Results Black patients were 8% and 14% more likely than white patients to experience spine surgery specific complications (adjusted odds ratios [aOR]: 1.08, 95% confidence interval [CI]: 1.03-1.13) and general postoperative complications (aOR: 1.14, 95% CI: 1.07-1.20), respectively. Black patients, compared with white patients, also had increased adjusted odds of 30-day readmissions (aOR: 1.13, 95% CI: 1.07-1.20), 90-day readmissions (aOR: 1.07, 95% CI: 1.02-1.13), longer length of stay (LOS) (adjusted Incidence Rate Ratio: 1.15, 95% CI: 1.14-1.16), and higher total charges (adjusted Incidence Rate Ratio: 1.08, 95% CI: 1.07-1.09). Conclusion Our findings demonstrate that black patients, as compared with white patients, are more likely to have postoperative complications, longer postoperative lengths of stay, higher total hospital charges, and increased odds of 30- and 90-day readmissions following lumbar spinal fusion surgery. Level of evidence 4.

Utilization of Predictive Modeling to Determine Episode of Care Costs and to Accurately Identify Catastrophic Cost Nonwarranty Outlier Patients in Adult Spinal Deformity Surgery: A Step Toward Bundled Payments and Risk Sharing.

Abstract: STUDY DESIGN Retrospective review of prospectively-collected, multicenter adult spinal deformity (ASD) database. OBJECTIVE The aim of this study was to evaluate the rate of patients who accrue catastrophic cost (CC) with ASD surgery utilizing direct, actual costs, and determine the feasibility of predicting these outliers. SUMMARY OF BACKGROUND DATA Cost outliers or surgeries resulting in CC are a major concern for ASD surgery as some question the sustainability of these surgical treatments. METHODS Generalized linear regression models were used to explain the determinants of direct costs. Regression tree and random forest models were used to predict which patients would have CC (>$100,000). RESULTS A total of 210 ASD patients were included (mean age of 59.3 years, 83% women). The mean index episode of care direct cost was $70,766 (SD = $24,422). By 90 days and 2 years following surgery, mean direct costs increased to $74,073 and $77,765, respectively. Within 90 days of the index surgery, 11 (5.2%) patients underwent 13 revisions procedures, and by 2 years, 26 (12.4%) patients had undergone 36 revision procedures. The CC threshold at the index surgery and 90-day and 2-year follow-up time points was exceeded by 11.9%, 14.8%, and 19.1% of patients, respectively. Top predictors of cost included number of levels fused, surgeon, surgical approach, interbody fusion (IBF), and length of hospital stay (LOS). At 90 days and 2 years, a total of 80.6% and 64.0% of variance in direct cost, respectively, was explained in the generalized linear regression models. Predictors of CC were number of fused levels, surgical approach, surgeon, IBF, and LOS. CONCLUSION The present study demonstrates that direct cost in ASD surgery can be accurately predicted. Collectively, these findings may not only prove useful for bundled care initiatives, but also may provide insight into means to reduce and better predict cost of ASD surgery outside of bundled payment plans. LEVEL OF EVIDENCE 3.

Spinal Stenosis Grading in Magnetic Resonance Imaging Using Deep Convolutional Neural Networks.

Abstract: Study design Retrospective magnetic resonance imaging grading with comparison between experts and deep convolutional neural networks (CNNs). Objective This study aims to verify the feasibility of a computer-assisted spine stenosis grading system by comparing the diagnostic agreement between two experts and the agreement between the experts and trained artificial CNN classifiers. Summary of background data Spinal stenosis grading is important; however, it is tedious job to check the MR images slide by slide to classify patient grades often having different opinions regarding the final diagnosis. Methods For 542 L4-5 axial MR images, two experts independently localized the center position of the spine canal and graded the status. Two CNN classifiers each trained with the grading label made by the two experts were validated using 10-fold cross-validation. Each classifier consisted of a CNN detection model responsible for the localization of patches near the canal and a classification CNN model to predict the spinal stenosis status in the localized patches. Faster R-CNN was used for the detection model whereas VGG network was used for the classification model. A comparison in grading agreement was carried out between the two experts as well as that of the experts and the prediction results generated by the CNN models. Results Grading agreement between the experts was 77.5% and 75% in terms of accuracy and F1 scores. The agreement between the first expert and the model trained with the labels of the first expert was 83% and 75.4%, respectively. The agreement between the second expert and the model trained with the labels of the second expert was 77.9% and 74.9%. The differences between the two experts were significant, whereas the differences between each expert and the trained models were not significant. Conclusion We indeed confirmed that automatic diagnosis using deep learning may be feasible for spinal stenosis grading. Level of evidence 4.

Preoperative Mental Health Component Scoring Is Related to Patient Reported Outcomes Following Lumbar Fusion.

Abstract: STUDY DESIGN Retrospective cohort review. OBJECTIVE The objective of this study was to identify depression using the Mental Component Score (MCS-12) of the Short Form-12 (SF-12) survey and to correlate with patient outcomes. SUMMARY OF BACKGROUND DATA The impact of preexisting depressive symptoms on health-care related quality of life (HRQOL) outcomes following lumbar spine fusion is not well understood. METHODS Patients undergoing lumbar fusion between one to three levels at a single center, academic hospital were retrospectively identified. Patients under the age of 18 years and those undergoing surgery for infection, trauma, tumor, or revision, and less than 1-year follow-up were excluded. Patients with depressive symptoms were identified using an existing clinical diagnosis or a score of MCS-12 less than or equal to 45.6 on the preoperative SF-12 survey. Absolute HRQOL scores, the recovery ratio (RR) and the percent of patients achieving minimum clinically important difference (MCID) between groups were compared, and a multiple linear regression analysis was performed. RESULTS A total of 391 patients were included in the total cohort, with 123 (31.5%) patients reporting symptoms of depression based on MCS-12 and 268 (68.5%) without these symptoms. The low MCS-12 group was found to have significantly worse preoperative Oswestry disability index (ODI), visual analogue scale back pain (VAS Back) and visual analogue scale leg pain (VAS Leg) scores, and postoperative SF-12 physical component score (PCS-12), ODI, VAS Back, and VAS Leg pain scores (P < 0.05) than the non-depressed group. Finally, multiple linear regression analysis revealed preoperative depression to be a significant predictor of worse outcomes after lumbar fusion. CONCLUSION Patients with depressive symptoms, identified with an MCS-12 cutoff below 45.6, were found to have significantly greater disability in a variety of HRQOL domains at baseline and postoperative measurement, and demonstrated less improvement in all outcome domains included in the analysis compared with patients without depression. However, while the improvement was less, even the low MCS-12 cohort demonstrated statistically significant improvement in all HRQOL outcome measures after surgery. LEVEL OF EVIDENCE 3.

Do PROMIS Physical Function, Pain Interference, and Depression Correlate to the Oswestry Disability Index and Neck Disability Index in Spine Trauma Patients?

Abstract: STUDY DESIGN Correlational study. OBJECTIVE In spine trauma patients, we aimed to assess the correlation of patient-reported outcome measurement information system (PROMIS) physical function (PF), pain interference (PI), and Depression scores with Oswestry Disability Index (ODI) and Neck Disability Index (NDI) ODI/NDI scores. SUMMARY OF BACKGROUND DATA The ODI and NDI were intended as patient-reported outcome measures (PROMs) to evaluate clinical outcomes in patients seeking spine care. To date, the PROMIS has not been studied in the spine trauma population. METHODS Between January 1, 2015 and December 13, 2017, patients presenting to a single, level 1 trauma center spine clinic with known spine trauma were identified. A total of 56 patients (52 operative, 4 nonoperative) representing 181 encounters were identified. PROMIS PF, PI, and Depression, as well as the ODI or NDI, were administered to patients. Spearman rho (ρ) were calculated between PROMs. RESULTS A strong correlation exists between PROMIS PI and the ODI (ρ = 0.79, P < 0.001), while a strong-moderate correlation exists between PROMIS PF and the ODI (ρ = -0.61, P < 0.001). A moderate correlation exists between PROMIS Depression and the ODI (ρ = 0.54, P < 0.001). Strong correlations exist between PROMIS PI and the NDI (ρ = 0.71, P < 0.001) and PROMIS Depression and the NDI (ρ = 0.73, P < 0.001). A poor correlation exists between PROMIS PF and the NDI (ρ = -0.28, P = 0.005). CONCLUSION PROMIS PF, PI, and Depression domains significantly correlate with the ODI and NDI; however, only PROMIS PI strongly correlates with both the NDI and ODI. This suggests that PROMIS PI can be used to capture similar information to that of the ODI or NDI but that PROMIS PF and Depression may offer additional clinical information. LEVEL OF EVIDENCE 2.