Faculty Bibliography

BACKGROUND:Prior studies of coccygectomy consist of small patient groups, heterogeneous techniques, and high wound complication rates (up to 22%). This study investigates our institution's experience with coccygectomy using a novel "off-center" wound closure technique and analyzes prognostic factors for long-term successful clinical outcomes. METHODS:Retrospective review of all patients who underwent coccygectomy from 2006 to 2019 at a single center. Demographics, mechanism of injury, conservative management, morphology (Postacchini and Massobrio), and postoperative complications were collected. Preoperative and postoperative Oswestry Disability Index (ODI), visual analog scale (VAS), Patient-Reported Outcomes Measurement Information System-29 (PROMIS-29), and EuroQol-5D (EQ-5D) were compared. Risk factors for failing to meet minimum clinically importance difference for ODI and PROMIS-physical function/pain interference were identified. Risk factors for remaining disabled after surgery (ODI <20) and factors associated with VAS and EQ-5D improvement were investigated using stepwise logistic regression. RESULTS:<0.05). CONCLUSIONS:This is the largest series of coccygectomy patients demonstrating improvement in long-term outcomes. Compared to previous studies, our cohort had a lower wound infection rate, which we attribute to an "off-center" closure. CLINICAL RELEVANCE/CONCLUSIONS:Patients should be counseled that their surgical history, along with age, gender, and etiology of pain can influence success following coccygectomy. These data can help surgeons set realistic expectations following surgery. LEVEL OF EVIDENCE/METHODS:3.

BACKGROUND:Adult spinal deformity (ASD) surgery can entail complex reconstructive procedures. It is unclear whether there is any effect of case start time on outcomes. We sought to evaluate the effects of case start time and day of the week on 90-day complication, readmission, and revision rates after ASD surgery. METHODS:This is a retrospective study of 1040 ASD patients from a single institution. We collected start times and day of the week for cases from 2011 to 2018. Early start was designated as any case starting either before or at 7:30 am or between 7:30 and 11 am; late start was designated as any case starting at 11 am or later. Outcome measures include 90-day complication, revision, and readmission rates. RESULTS:= 0.046). CONCLUSIONS:A late OR start time was predictive of increased risk for neurologic complication, 90-day readmission, and unplanned reoperation. The well-established protocols for first start OR times for elective ASD surgery may decrease outcome risk and reduce variability in complication rates. CLINICAL RELEVANCE/CONCLUSIONS:Understanding the impact of start time on outcomes and complications after ASD surgery is helpful for surgeons in preoperative planning and for institutions and hospitals' allocation of operating room staff and resources. LEVEL OF EVIDENCE/METHODS:3.

OBJECTIVE:Minimally invasive surgery (MIS) for adult spinal deformity (ASD) can offer deformity correction with less tissue manipulation and damage. However, the impact of obesity on clinical outcomes and radiographic correction following MIS for ASD is poorly understood. The goal of this study was to determine the role, if any, that obesity has on radiographic correction and health-related quality-of-life measures in MIS for ASD. METHODS:Data were collected from a multicenter database of MIS for ASD. This was a retrospective review of a prospectively collected database. Patient inclusion criteria were age ≥ 18 years and coronal Cobb angle ≥ 20°, pelvic incidence-lumbar lordosis mismatch ≥ 10°, or sagittal vertical axis (SVA) > 5 cm. A group of patients with body mass index (BMI) < 30 kg/m2 was the control cohort; BMI ≥ 30 kg/m2 was used to define obesity. Obesity cohorts were categorized into BMI 30-34.99 and BMI ≥ 35. All patients had at least 1 year of follow-up. Preoperative and postoperative health-related quality-of-life measures and radiographic parameters, as well as complications, were compared via statistical analysis. RESULTS:A total of 106 patients were available for analysis (69 control, 17 in the BMI 30-34.99 group, and 20 in the BMI ≥ 35 group). The average BMI was 25.24 kg/m2 for the control group versus 32.46 kg/m2 (p < 0.001) and 39.5 kg/m2 (p < 0.001) for the obese groups. Preoperatively, the BMI 30-34.99 group had significantly more prior spine surgery (70.6% vs 42%, p = 0.04) and worse preoperative numeric rating scale leg scores (7.71 vs 5.08, p = 0.001). Postoperatively, the BMI 30-34.99 cohort had worse Oswestry Disability Index scores (33.86 vs 23.55, p = 0.028), greater improvement in numeric rating scale leg scores (-4.88 vs -2.71, p = 0.012), and worse SVA (51.34 vs 26.98, p = 0.042) at 1 year postoperatively. Preoperatively, the BMI ≥ 35 cohort had significantly worse frailty (4.5 vs 3.27, p = 0.001), Oswestry Disability Index scores (52.9 vs 44.83, p = 0.017), and T1 pelvic angle (26.82 vs 20.71, p = 0.038). Postoperatively, after controlling for differences in frailty, the BMI ≥ 35 cohort had significantly less improvement in their Scoliosis Research Society-22 outcomes questionnaire scores (0.603 vs 1.05, p = 0.025), higher SVA (64.71 vs 25.33, p = 0.015) and T1 pelvic angle (22.76 vs 15.48, p = 0.029), and less change in maximum Cobb angle (-3.93 vs -10.71, p = 0.034) at 1 year. The BMI 30-34.99 cohort had significantly more infections (11.8% vs 0%, p = 0.004). The BMI ≥ 35 cohort had significantly more implant complications (30% vs 11.8%, p = 0.014) and revision surgery within 90 days (5% vs 1.4%, p = 0.034). CONCLUSIONS:Obese patients who undergo MIS for ASD have less correction of their deformity, worse quality-of-life outcomes, more implant complications and infections, and an increased rate of revision surgery compared with their nonobese counterparts, although both groups benefit from surgery. Appropriate counseling should be provided to obese patients.

SUMMARY OF BACKGROUND DATA/BACKGROUND:The impact of not achieving ideal realignment in the global alignment and proportion (GAP) score in adult spinal deformity (ASD) correction on clinical outcomes is understudied at present. OBJECTIVE:To identify the clinical impact of failing to achieve GAP proportionality in ASD surgery. STUDY DESIGN/METHODS:Retrospective cohort. METHODS:Operative ASD patients with fusion to S1/pelvis and with pre-(BL) and 2-year (2Y) data were included. Patients were assessed for matching their 6-week (6W) age-adjusted alignment goals.1 Patients were stratified by age-adjusted match at 6W postoperatively (Matched) and 6W GAP proportionality (proportioned: GAP-P; moderately disproportioned: GAP-MD; severely disproportioned: GAP-SD). Groups were assessed for differences in demographics, surgical factors, radiographic parameters, and complications occurring by 2Y. Multivariable logistic regression was used to assess independent effects of not achieving GAP proportionality on postoperative outcomes for Matched and Unmatched patients. RESULTS:Included: One hundred twenty three ASD patients. At baseline, 39.8% were GAP-SD, and 12.2% GAP-SD at 6W. Of 123 patients, 51.2% (n = 63) had more than or equal to one match at 6W. GAP-SD rates did not differ by being Matched or Unmatched (P = 0.945). GAP-SD/Unmatched patients had higher rates of reoperation, implant failure, and PJF by 2Y postop (all P < 0.05). Regressions controlling for age at BL, levels fused, and CCI, revealed 6W GAP-SD/Unmatched patients had higher odds of reoperation (OR: 54 [3.2-899.9]; P = 0.005), implant failure (OR: 6.9 [1.1-46.1]; P = 0.045), and PJF (OR: 30.1 [1.4-662.6]; P = 0.031). Compared to GAP-P or GAP-MD patients, GAP-SD/Matched patients did not have higher rates of reoperation, implant failure, or junctional failure (all P > 0.05). The regression results for both Matched and Unmatched cohorts were consistent when proportionality was substituted by the continuous GAP score. CONCLUSION/CONCLUSIONS:In ASD patients who meet age-adjusted realignment goals, GAP proportionality does not significantly alter complication rates. However, GAP proportionality remains an important consideration in patients with sub-optimal age-adjusted alignment. In these cases, severe global disproportion is associated with higher rates of reoperation, implant failure, rod fracture, and junctional failure.Level of Evidence: III.

STUDY DESIGN/METHODS:Retrospective single-center, consecutively enrolled database of adult spinal deformity (ASD) patients. OBJECTIVE:To assess the performance of the mASD-FI in predicting clinical and patient-reported outcomes after ASD-corrective surgery. SUMMARY OF BACKGROUND DATA/BACKGROUND:The recently described modified Adult Spinal Deformity frailty index (mASD-FI) quantifies frailty of ASD patients, but the utility of this clinical prediction tool as a means of prognosticating postoperative outcomes has not been investigated. METHODS:ASD patients with available mASD-FI scores and HRQL data at presentation and 2-years postop were included. Patients were stratified by mASD-FI score using published cutoffs: not frail (NF,<7), frail (F,7-12), severely frail (SF,>12). ANOVA assessed differences in patient factors across frailty groups. Linear regression assessed the relationship of mASD-FI with length of stay(LOS) and HRQLs. Multivariable logistic regression revealed how frailty category predicted odds of complications, infections and reoperation. RESULTS:509 pts included (59yrs, 79%F, 27.7 kg/m2). The cohort presented with moderate baseline deformity: SVA (83.7mm±71), PT (12.7°±10.8), PI-LL (43.1°±21.1). Mean preoperative mASD-FI score was 7.2, frailty category: NF (50.3%), F (34.0%), SF (15.7%). Age, BMI, and CCI increased with frailty categories (all p < 0.001); however, fusion length (p = 0.247) and osteotomy rate (p = 0.731) did not. At baseline, increasing frailty was associated with inferior ODI, EQ-5D, SRS-22r, PCS, and NRS Back and Leg (all p < 0.001). Greater frailty was associated with increased LOS and reduced postoperative HRQL. Controlling for complication incidence, baseline mASD-FI predicted 2 year postop scores for year ODI (b = 0.7, 0.58-0.8, p < 0.001) SRS (b = -0.023, -0.03 - -0.02, p < 0.001), EQ-5D (b = -0.003, -0.004 - -0.002, p < 0.001). F and SF were associated with greater odds of unplanned revision surgery and complications. CONCLUSION/CONCLUSIONS:Higher preoperative mASD-FI score was associated with significantly greater complications, higher rate of unplanned reoperations and lower postoperative HRQL in this investigation. The mASD-FI provides similar prognostic utility while reducing burden for surgeons and patients.

BACKGROUND:Primary spine paragangliomas are rare tumors. Surgical resection plays a role, but aggressive lesions are challenging. We reviewed the literature on primary spine paragangliomas. METHODS:PubMed, Scopus, Web of Science, and Cochrane were searched upon the PRISMA guidelines to include studies on primary spine paragangliomas. Clinical-radiological features, treatments, and outcomes were analyzed and compared between cauda-equina vs non-cauda-equina tumors. RESULTS:We included 143 studies comprising 334 patients. Median age was 46 years (range, 6-85). The most frequent symptoms were lower-back (64.1%) and radicular (53.9%) pain, and sympathetic in 18 patients (5.4%). Cauda-equina paragangliomas (84.1%) had frequently lumbar (49.1%) or lumbosacral (29%) locations. Non-cauda-equina tumors were mostly in the thoracic (11.4%), thoracolumbar (5.1%), and cervical (3.6%) spine. Median tumor diameter was 2.5cm (range, 0.5-13.0). Surgical resection (98.5%) was preferred over biopsy (1.5%). Decompressive laminectomy (53%) and spine fusion (6.9%) were also performed. Adjuvant radiotherapy was delivered in 39 patients (11.7%) with aggressive tumors. Post-treatment symptomatic improvement was described in 86.2% cases. Median follow-up was 19.5 months (range, 0.1-468.0), and 23 patients (3.9%) had tumor recurrences. No significant differences were found between cauda-equina vs non-cauda-equina tumors. CONCLUSION/CONCLUSIONS:Surgical resection is effective and safe in treating primary spine paragangliomas; however, adjuvant treatments may be needed for aggressive lesions.

OBJECTIVE:The authors' objective was to determine whether preoperative lateral extension cervical spine radiography can be used to predict osteotomy type and postoperative alignment parameters after cervical spine deformity surgery. METHODS:A total of 106 patients with cervical spine deformity were reviewed. Radiographic parameters on preoperative cervical neutral and extension lateral radiography were compared with 3-month postoperative radiographic alignment parameters. The parameters included T1 slope, C2 slope, C2-7 cervical lordosis, cervical sagittal vertical axis, and T1 slope minus cervical lordosis. Associations of radiographic parameters with osteotomy type and surgical approach were also assessed. RESULTS:On extension lateral radiography, patients who underwent lower grade osteotomy had significantly lower T1 slope, T1 slope minus cervical lordosis, cervical sagittal vertical axis, and C2 slope. Patients who achieved more normal parameters on extension lateral radiography were more likely to undergo surgery via an anterior approach. Although baseline parameters were significantly different between neutral lateral and extension lateral radiographs, 3-month postoperative lateral and preoperative extension lateral radiographs were statistically similar for T1 slope minus cervical lordosis and C2 slope. CONCLUSIONS:Radiographic parameters on preoperative extension lateral radiography were significantly associated with surgical approach and osteotomy grade and were similar to those on 3-month postoperative lateral radiography. These results demonstrated that extension lateral radiography is useful for preoperative planning and predicting postoperative alignment.

STUDY DESIGN/METHODS:Retrospective cohort study. OBJECTIVE:Determine whether screws per level and rod material/diameter are associated with incidence of proximal junctional kyphosis (PJF). SUMMARY OF BACKGROUND DATA/BACKGROUND:PJF is a common and particularly adverse complication of adult spinal deformity (ASD) surgery. There is evidence that the rigidity of posterior spinal constructs may impact risk of PJF. METHODS:Patients with ASD and 2-year minimum follow-up were included. Only patients undergoing primary fusion of more than or equal to five levels with lower instrumented vertebrae (LIV) at the sacro-pelvis were included. Screws per level fused was analyzed with a cutoff of 1.8 (determined by receiver operating characteristic curve (ROC) analysis). Multivariable logistic regression was utilized, controlling for age, body mass index (BMI), 6-week postoperative change from baseline in lumbar lordosis, number of posterior levels fused, sex, Charlson comorbidity index, approach, osteotomy, upper instrumented vertebra (UIV), osteoporosis, preoperative TPA, and pedicle screw at the UIV (as opposed to hook, wire, etc.). RESULTS:In total, 504 patients were included. PJF occurred in 12.7%. The mean screws per level was 1.7, and 56.8% of patients had less than 1.8 screws per level. No differences were observed between low versus high screw density groups for T1-pelvic angle or magnitude of lordosis correction (both P > 0.15). PJF occurred in 17.0% versus 9.4% of patients with more than or equal to 1.8 versus less than 1.8 screws per level, respectively (P < 0.05). In multivariable analysis, patients with less than 1.8 screws per level exhibited lower odds of PJF (odds ratio (OR) 0.48, P < 0.05), and a continuous variable for screw density was significantly associated with PJF (OR 3.87 per 0.5 screws per level, P < 0.05). Rod material and diameter were not significantly associated with PJF (both P > 0.1). CONCLUSION/CONCLUSIONS:Among ASD patients undergoing long-segment primary fusion to the pelvis, the risk of PJF was lower among patients with less than 1.8 screws per level. This finding may be related to construct rigidity. Residual confounding by other patient and surgeon-specific characteristics may exist. Further biomechanical and clinical studies exploring this relationship are warranted.Level of Evidence: 3.

PURPOSE/OBJECTIVE:To determine the validity and responsiveness of PROMIS metrics versus the SRS-22r questionnaire in adult spinal deformity (ASD). METHODS:Surgical ASD patients undergoing ≥ 4 levels fused with complete baseline PROMIS and SRS-22r data were included. Internal consistency (Cronbach's alpha) and test-retest reliability [intraclass correlation coefficient (ICC)] were compared. Cronbach's alpha and ICC values ≥ 0.70 were predefined as satisfactory. Convergent validity was evaluated via Spearman's correlations. Responsiveness was assessed via paired samples t tests with Cohen's d to assess measure of effect (baseline to 3 months). RESULTS:One hundred and ten pts are included. Mean baseline SRS-22r score was 2.62 ± 0.67 (domains = Function: 2.6, Pain: 2.5, Self-image: 2.2, Mental Health: 3.0). Mean PROMIS domains = Physical Function (PF): 12.4, Pain Intensity (PI): 91.7, Pain Interference (Int): 55.9. Cronbach's alpha, and ICC were not satisfactory for any SRS-22 and PROMIS domains. PROMIS-Int reliability was low for all SRS-22 domains (0.037-0.225). Convergent validity demonstrated strong correlation via Spearman's rho between PROMIS-PI and overall SRS-22r (- 0.61), SRS-22 Function (- 0.781), and SRS-22 Pain (- 0.735). PROMIS-PF had strong correlation with SRS-22 Function (0.643), while PROMIS-Int had moderate correlation with SRS-22 Pain (- 0.507). Effect size via Cohen's d showed that PROMIS had superior responsiveness across all domains except for self-image. CONCLUSIONS:PROMIS is a valid measure compared to SRS-22r in terms of convergent validity, and has greater measure of effect in terms of responsiveness, but failed in reliability and internal consistency. Surgeons should consider the lack of reliability and internal consistency (despite validity and responsiveness) of the PROMIS to SRS-22r before replacing the traditional questionnaire with the computer-adaptive testing.