Faculty Bibliography

STUDY DESIGN/METHODS:Retrospective analysis of a multicenter series of deformity patients undergoing thoracolumbar instrumentation to the pelvis. OBJECTIVE:Introduce the C2 coronal angle (C2C) as a novel metric, assess its association with quality-of-life and neck-specific outcomes, and compare the strength of this association with the traditional linear C7-CSVL offset. SUMMARY OF BACKGROUND DATA/BACKGROUND:While assessment of the sagittal plane incorporates vertebropelvic angles for surgical planning, angular coronal measurements have not been evaluated as predictors of patient-reported outcomes following adult spinal deformity (ASD) surgery. METHODS:Demographics, comorbidities, and radiographic parameters were collected preoperatively and at 2-year follow-up. Coronal angles were measured between CSVL and the center of the C2 body (C2C). Primary endpoints were patient‑reported outcomes at two years (SRS‑22, SF‑36, NDI) and whether patients achieved the minimal clinically important difference (MCID). Univariable and multivariable regression models examined the relationship between C2C and PROMs. An ROC analysis with Youden's Index identified optimal C2C thresholds for predicting NDI >20. RESULTS:Among 328 patients (mean age 64.0 years, 12.6 levels fused), postoperative absolute C2C was independently associated with PROMs. Each 1° increase in C2C was associated with decreased 2-yr SRS-Total (P=0.014) and activity (P=0.024), pain (P=0.033), and mental health (P=0.029) subdomains. Each 1° increase reduced odds of achieving NDI MCID by 34% (OR=0.66, P=0.022). ROC identified an optimal C2C threshold of 3.5°. Patients exceeding this had nearly twice the odds of neck disability (OR=1.90, P=0.049) and significantly lower SF-36 Physical Component (P=0.004) and Physical Functioning (P=0.011) scores. C2C was more strongly associated with SRS-Total than C7-CSVL (AIC=657 vs. 660; adj. R²=0.058 vs.0.048). CONCLUSIONS:Achieving postoperative C2C ≤3.5° is independently associated with reduced neck disability and optimized quality of life after ASD surgery. C2C was more strongly associated with SRS-Total than C7-CSVL and could be considered as a complementary measure of coronal alignment.

INTRODUCTION/BACKGROUND:Predicting post-operative changes in thoracic kyphosis (TK) remains challenging in adult spinal deformity (ASD) surgery. This study aimed to quantify both iatrogenic and reciprocal changes in TK following lumbar correction and assess their maintenance at 2-year follow-up. METHODS:A retrospective analysis was performed on 356 ASD patients treated with posterior instrumentation from T9-11 to the pelvis, with a minimum 2-year follow-up. TK values were compared with normative data. Multivariate analysis identified thoracolumbar parameters associated with reciprocal thoracic changes and proximal failure. RESULTS:=0.40). Between 6 weeks and 2 years, 9.3% experienced TK decompensation >15°, and 9.6% required proximal extension for junctional issues-defined collectively as "thoracic failures" (17.4%). Independent predictors of failure included advanced age (OR 3.6), more proximal lumbar correction (OR 1.9), and pronounced early mid-thoracic kyphosis (OR 2.3). CONCLUSION/CONCLUSIONS:In ASD surgery with Upper Instrumented Vertebra (UIV) between T9 and T11, changes in TK were largely proportional to lumbar correction, leading to normalization in most cases. However, age, the location of lumbar correction, and early post-operative thoracic shape independently predicted thoracic failure, highlighting the need for tailored alignment strategies.

Study DesignRetrospective cohort study.ObjectivesTo characterize longitudinal durability of cervical deformity (CD) correction, identify predictors of alignment failure, and define failure mechanism timing across the first postoperative year.Methodsof 155 operative CD patients in a prospectively maintained multicenter database, 89 had complete four-timepoint radiographic follow-up. Well-alignment was defined as cSVA <4 cm. Patients were grouped as A (maintained), B (corrected then deteriorated), or C (never aligned). Analyses included Cox regression (n=47, 17 events), Kaplan-Meier with restricted mean survival time (RMST), and mixed-effects logistic regression across four timepoints (n=356; ICC=0.36). Concurrent thoracolumbar deformity was excluded.ResultsWell-aligned proportion fell from 48.3% at 3 months to 33.7% at 1 year (A=34%, B=19%, C=47%). DJK was most strongly associated with alignment loss (HR 5.21, 95% CI 1.94-13.98; OR 0.09), with alignment maintained 4.1 versus 9.8 months (RMST difference 5.7, p=0.001). Lower postoperative cSVA paradoxically increased failure hazard (HR 0.58/10 mm, p=0.002). Older patients deteriorated faster (Time×Age OR 0.88, p=0.022). Failure mechanisms shifted from DJK at 3 months (50%) to PJK at 6 months (75%) to global compensation loss at 1 year (71%). No surgical parameters differed between groups.ConclusionsFewer than one-third of patients maintain alignment at 1 year. DJK, advanced age, and lower postoperative cSVA were most strongly associated with failure (17 events; limited precision). Mechanisms appeared to shift from junctional failure early to global decompensation late. Alignment loss was not accompanied by significant 1-year NDI or EQ-5D differences, framing radiographic deterioration as an early surveillance marker rather than clinical failure. Individualized risk stratification and surveillance are supported.

STUDY DESIGN/METHODS:Multicenter retrospective cohort study. PURPOSE/OBJECTIVE:To compare 2-year sagittal alignment outcomes between two-row vertebral body tethering (2RVBT) and posterior spinal fusion (PSF) in adolescent idiopathic scoliosis (AIS). BACKGROUND:PSF remains the gold standard for AIS correction; however, concerns regarding motion loss and adjacent segment disease have encouraged development of fusionless techniques such as vertebral body tethering (VBT). While VBT has demonstrated promising coronal correction, evidence regarding its effects on sagittal alignment is limited. METHODS:Ninety-nine AIS patients (49 2RVBT, 50 PSF) with ≥ 2-year follow-up were analyzed. Radiographic parameters included sagittal vertical axis (SVA), cervical sagittal vertical axis (cSVA), cervical lordosis (CL), pelvic tilt (PT), L4-S1 lordosis, T1 pelvic angle (TPA), and pelvic incidence-lumbar lordosis mismatch (PI-LL). The minimal clinically important difference (MCID) was prespecified as 5 mm for sagittal axis and 10° for lordosis, with pediatric thresholds of 3 mm and 5° based on AIS literature. Institutional Review Board approval was obtained at all participating centers. Inclusion criteria were AIS diagnosis, age ≤ 16 years at surgery, lumbar instrumentation, and ≥ 2-year follow-up. Exclusion criteria included neuromuscular/syndromic scoliosis and prior spinal surgery. RESULTS:2RVBT patients were younger, more skeletally immature (Risser 1.6 ± 0.8 vs. 2.6 ± 1.8, p = 0.001), and more frequently female (97% vs. 84%, p = 0.048). At baseline, sagittal parameters differed between groups, with lower SVA, cervical lordosis, and L4 to S1 lordosis, and higher cSVA in the 2RVBT group. At 2 years, 2RVBT maintained greater L4-S1 lordosis (36.0° vs. 18.3°, p = 0.001) and cSVA (3.4 mm vs. - 3.7 mm, p = 0.001), with lower CL (-4.3° vs. 7.0°, p = 0.001). Between-group changes from baseline to 2 years did not exceed MCID thresholds. Findings were unchanged in a Risser matched sensitivity analysis, with balanced baseline demographics and sagittal parameters and no between group changes exceeding prespecified MCID thresholds. CONCLUSION/CONCLUSIONS:2RVBT and PSF produce comparable sagittal alignment changes at 2 years, with no between-group differences in change from baseline exceeding MCID thresholds. 2RVBT preserves motion without compromising sagittal balance in skeletally immature AIS patients.

PURPOSE/OBJECTIVE:To determine whether changes in intraoperative neuromonitoring with saphenous nerve somatosensory evoked potential (SSEP) stimulation, preoperative assessment of  lumbar plexus location, and screw placement, are associated with thigh paresthesia development following an anterior-to-the-psoas (ATP) approach for vertebral body tethering (VBT) in adolescent idiopathic scoliosis (AIS) patients. METHODS:39 patients who underwent a thoracoabdominal ATP approach for VBT with a minimum 2-year follow-up were included. Neurologic monitoring variables, including saphenous nerve SSEPs and quadriceps motor evoked potentials (MEPs), psoas location, an indicator of lumbar plexus location, and screw placement were compared between patients with and without postoperative thigh paresthesia. Demographics and outcomes were analyzed using the Mann-Whitney U test and Fisher's exact test as appropriate, with statistical significance set at p < 0.05. RESULTS:41% of patients experienced postoperative thigh paresthesia. Additionally, 10% reported transient thigh numbness. No patients developed motor deficits. Lumbar plexus position and screw distance did not significantly differ between groups, and no neuromonitoring alarms occurred during psoas retraction. Although changes in quadriceps MEPs were not statistically associated with postoperative sensory symptoms, a higher proportion of patients with paresthesia demonstrated MEP changes (50% vs 19%, p = 0.063) and decreased MEP amplitudes (31% vs 13%, p = 0.077), representing a directional difference. All sensory symptoms resolved without intervention at a mean of 5.3 ± 5.6 weeks and a median of 2.5 (IQR 1-10). CONCLUSION/CONCLUSIONS:Changes in intraoperative neuromonitoring with saphenous nerve SSEP stimulation, psoas location, and screw positioning were not statistically associated with postoperative thigh paresthesia following the ATP approach for VBT in AIS patients. However, a directional difference was observed between quadriceps MEP changes and postoperative thigh paresthesia. These findings highlight the complexity of neurologic responses and support further investigation into patient-specific anatomy, surgical technique, and optimization of neuromonitoring strategies.

BACKGROUND AND OBJECTIVES/OBJECTIVE:Anterior lumbar interbody fusion (ALIF) is an important technique offering biomechanical advantages including improved disk height restoration, correction of sagittal and coronal imbalance, and improved fusion. Although generally safe, vascular injury remains a serious complication. Specific vascular injury mechanisms, management, and outcomes are insufficiently reported. We seek to better characterize the incidence, mechanism, management, and sequelae of intraoperative vascular injuries during ALIF. METHODS:We performed a retrospective single-center study of adult patients undergoing ALIF between 2018 and 2022. All exposures were performed by a vascular surgeon. Data analyzed included patient demographics, operative characteristics, and vascular complications (classified as major or minor). The primary outcomes were the incidence of vascular injury and postoperative venous thromboembolism (VTE). Statistical analyses included χ2 testing and logistic regression. RESULTS:Of 418 patients, 26 (6.2%) sustained intraoperative vascular injuries, with 4 (1.0%) classified as major. Injuries were predominantly venous (n = 25), most frequently involving the left common iliac vein during L4-L5 exposure. One arterial dissection required stenting. Postoperative VTE occurred in 11 patients (2.6%); notably, 45.5% of these patients had sustained an intraoperative vascular injury. Vascular injury was a strong independent predictor of VTE (odds ratio [OR]: 15.9; P < .001; 95% CI: 4.3-58.8). The number of levels fused was significantly associated with both vascular injury (OR: 1.76; P = .007; 95% CI: 1.16-2.66) and VTE (OR: 1.91; P = .031; 95% CI: 1.03-3.42). No association was found between vascular complications and previous abdominal surgery, body mass index, revision surgery, age older than 50, spinal deformity, or sex. There was 0% perioperative mortality. CONCLUSION/CONCLUSIONS:Vascular complications during ALIF are infrequent but significantly elevate the risk of postoperative VTE. Injuries cluster at the L4-L5 level and often involve the left common iliac vein. Preoperative planning, careful surgical technique, and experienced vascular access support are critical to minimizing complications.

OBJECTIVE:Adult spinal deformity (ASD) surgery patients maintain upright posture by using numerous compensatory mechanisms. The distribution of this compensation throughout the skeleton has not been fully investigated. METHODS:Patients with lumbar deformity curves undergoing fusion from T10 to the pelvis were included. Groups were stratified by Scoliosis Research Society (SRS)-Schwab sagittal deformity severity (mild, moderate, and severe). Compensation was determined based on the published values of asymptomatic individuals by Bao et al. (2018), with patients outside 1 standard deviation of the mean values deemed to be compensating. Adequate deformity correction was determined based on matching published sagittal age-adjusted score (SAAS) criteria. Means comparisons tests assessed differences between cohorts at each time point. RESULTS:In total, 379 ASD patients were included (mean age 66.7 ± 10.2 years, body mass index 28.4 ± 5.4 kg/m2, Charlson Comorbidity Index 1.20 ± 1.73). In total, 23.8% of patients had mild deformity, 19.2% moderate, and 57% severe. The severe deformity cohort generally demonstrated the highest rates of compensation across all regions at different time points. At baseline, the severe and moderate cohorts demonstrated predominantly lower limb-dominant compensation, with the highest frequencies of compensation seen at the knee and pelvis. In the mild cohort, knee compensation was relieved by 1 year when adequate correction was achieved. For the moderate cohort, hip and pelvic compensation were relieved first, with knee compensatory relief occurring by 2 years. For the severe cohort, pelvic compensation was relieved first, with global lower limb and thoracic compensation subsequently occurring. CONCLUSIONS:There is notable variation in how ASD patients compensate as the severity of their deformity progresses. There is also variation in how these patterns are altered postoperatively.

STUDY DESIGN/METHODS:Retrospective review of multicenter, prospective cervical deformity database. OBJECTIVE:To compare outcomes of extension of fusion to the cervical spine versus the upper thoracic (UT) spine. SUMMARY OF BACKGROUND DATA/BACKGROUND:Proximal junctional kyphosis (PJK) management after thoracolumbar fusion requires extension of fusion to the proximal spinal segments. Unlike extensions to the less mobile thoracic segments, crossing the cervicothoracic junction (CTJ) involves more mobile cervical segments and creates different biomechanical influences and clinical outcomes. No study has compared the outcomes of extending fusion to the cervical versus the UT spine. METHODS:Patients with thoracic PJK who underwent revision with extension of fusion to either the cervical or UT (T1 or T2) spine were identified in a multicenter, prospective cervical deformity database. Patients with cervical upper instrumented vertebra (UIV) were subdivided into lower cervical (LC; C4-7) and upper cervical (UC; and occiput-C3) groups. Baseline demographics, surgical variables, radiographic outcomes, 2-year health-related quality-of-life scores, complications, and revision rates were analyzed. RESULTS:Fifty-one patients (mean age: 60.4±12.9 y; 91% female) with at least 2 years of follow-up were included. Twelve had extension to the UT, 20 to the LC, and 19 to the UC spine. Demographic data, Charlson Comorbidity Index, follow-up duration, surgical parameters, radiographic measurements, recurrent PJK and reoperation rates, and 2-year patient-reported outcome scores were similar across groups. The instrumentation failure rate was higher in the LC (25%) than in the UT (0%) and UC (8%) groups (P=0.03). CONCLUSIONS:Stopping fusion at T1 or T2 did not result in greater complication or reoperation rates than extending to the cervical spine. The instrumentation-related complication rate was higher for extension to the LC than to the UC or UT spine. Crossing the CTJ should be individualized, but may not prevent additional proximal junctional-level problems in the management of thoracolumbar fusion PJK. LEVEL OF EVIDENCE/METHODS:Level IV.

OBJECTIVE:To evaluate the feasibility of same-day (postoperative day 0; POD0) physical therapy (PT) following lumbar fusion and to identify factors associated with failure to participate. METHODS:This retrospective study analyzed prospectively collected data from patients undergoing single-level posterior spinal fusion (PSF), with or without anterior (ALIF) or lateral (LLIF) interbody fusion, between January and December 2024 at a single institution. A standardized POD0 PT protocol was implemented for eligible patients. Patients were categorized into two groups: successful POD0 PT (ambulatory on POD0) and unable to participate. Demographic and surgical variables were compared between groups. Reasons for inability to participate were recorded and categorized. RESULTS:Among 129 patients in whom POD0 PT was attempted, 84 (65%) successfully participated, while 45 (35%) were unable. There were no significant differences in age, sex, BMI, ASA class, operative time, estimated blood loss, or surgical approach between groups. Patients who successfully completed POD0 PT had a significantly shorter hospital length of stay compared to those who did not (3.4 ± 1.6 vs 5.8 ± 2.9 days, P < 0.001), with no differences in complication rates, discharge disposition, emergency department visits, or reoperation rates. The most common barriers to POD0 PT were postoperative pain, medical issues (e.g., orthostatic hypotension, nausea, dizziness), and anesthesia-related somnolence. Less common factors included postoperative restrictions and logistical issues such as brace availability. CONCLUSIONS:POD0 PT following lumbar fusion is feasible in the majority of patients and is associated with a shorter hospital stay without increased complications. Failure to participate was not associated with the baseline patient or surgical characteristics evaluated in this study. Instead, the most common barriers were postoperative pain, transient medical issues, and anesthesia-related somnolence, suggesting that optimization of modifiable perioperative factors may improve the implementation of POD0 PT.