Faculty Bibliography

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.

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.

OBJECTIVE:The aim of the study was to evaluate the safety and efficacy of initiating physical therapy (PT) on the day of surgery (i.e., postoperative day 0 [POD0]) in patients undergoing single-level lumbar fusion surgery, with a focus on hospital length of stay (LOS) and early postoperative outcomes. METHODS:The authors conducted a retrospective review of prospectively collected data from a single institution. Patients undergoing single-level lumbar fusion between August 2022 and December 2024 were included. Those with revision surgery, tumors, or infections were excluded. POD0 PT was implemented in January 2024. Patients treated prior to this date received POD1 PT. Demographic, surgical, and postoperative data were compared between the POD0 and POD1 PT groups. RESULTS:A total of 586 patients were analyzed (POD0, n = 84; POD1, n = 502). Baseline demographics and surgical characteristics were similar between the groups. The POD0 group had a significantly shorter LOS (mean 3.4 ± 1.6 vs 4.0 ± 2.7 days, p = 0.016), and the patients were more likely to be discharged home. No significant differences were found in postoperative complications, including cardiac, pulmonary, neurological, gastrointestinal, urinary, infectious, or mechanical issues. Rates of 30- and 90-day emergency department visits, readmissions, or reoperations were also comparable between the groups. CONCLUSIONS:Initiating PT on the day of surgery is associated with reduced LOS and an increased likelihood of home discharge, without increasing complications or worsening clinical outcomes. These findings support the safety and potential benefits of POD0 PT in enhancing early recovery following single-level lumbar fusion surgery.

STUDY DESIGN/METHODS:Retrospective review. OBJECTIVE:Determine if patients with different degrees of incidence (PI) have the capacity to compensate via pelvic retroversion before initiating lower extremity compensation. SUMMARY OF BACKGROUND DATA/BACKGROUND:Compensatory mechanisms in the spine are thought to help patients with deformities maintain sagittal alignment. Pelvic retroversion and thoracic hypokyphosis are key mechanisms that help maintain balance. When these mechanisms are exhausted, patients often flex their hips and bend their knees. METHODS:This was a retrospective radiographic analysis of the EOS images at a single institution. Various spinal sagittal parameters and lower extremity knee flexion measurements were performed. Patients were subcategorized according to PI. Knee flexion in these groups was correlated with various sagittal parameters to determine whether there were differences when knee flexion occurred based on the PI. RESULTS:Knee flexion was independently correlated with PI, pelvic tilt (PT), PI-lumbar lordosis mismatch (PI-LL), and T1 pelvic inclination angle (TPA) in multiple regression analyses (P < 0.05). In patients with lower PI, knee flexion occurred at a PT of 10-15 degrees, PI-LL mismatch of -5-0 degrees, and TPA of about 10-15 degrees. In those with high PI, knee flexion occurred at a PT of ∼25-30 degrees, PI-LL mismatch of ∼15-20 degrees, and TPA about 25 degrees. Those with a lower PI also more rapidly increased knee flexion with further increases in PI-LL mismatch and TPA compared with those with a higher PI. CONCLUSION/CONCLUSIONS:This study demonstrates that patients with different PI have different capacities to compensate for increasing sagittal plane deformity before initiating knee flexion lower extremity compensation. Those with a lower PI retroverted their pelvis less and begin knee compensation earlier than those with a higher PI. These findings are important for surgical planning in patients with differing PI who are compensating for knee flexion.

STUDY DESIGN/METHODS:Retrospective cohort study of patients undergoing single-level L5-S1 anterior or transforaminal lumbar interbody fusion between 2012 and 2024 at a single academic institution, with preoperative and one-year postoperative radiographic assessment of sagittal alignment parameters. OBJECTIVE:To quantify changes in lumbar pelvic angle (LPA), pelvic tilt (PT), global lumbar lordosis (L1-S1), regional lumbar lordosis (L4-S1), and segmental lumbar lordosis (L5-S1) among single-level L5-S1 ALIF and TLIF patients. SUMMARY OF BACKGROUND DATA/BACKGROUND:Restoration of sagittal alignment is a primary goal of lumbar fusion. While ALIF is regarded as superior to TLIF in restoring segmental lordosis, its effect on global and regional alignment remains uncertain, and few studies directly compare their impact on spinopelvic parameters. METHODS:The electronic medical record was queried for patients who underwent single-level L5-S1 ALIF or TLIF with preoperative and one-year postoperative imaging. Sagittal parameters were measured using Surgimap software. Group comparisons were assessed with unpaired t-tests or Wilcoxon signed-rank tests. RESULTS:Radiographic measurements were available for 174 patients (ALIF n=73, TLIF n=101). ALIF patients had significantly greater improvement in L4-S1 (+4.2° vs. -1.1°, P=0.002) and L5-S1 lordosis (+4.6° vs. -4.8°, P<0.001). No significant differences were observed in postoperative changes for L1-S1 lordosis (+2.2° vs. -1.4°, P=0.250), LPA (-1.9° vs. -1.4°, P=0.743), or PT (-0.9° vs. +0.4°, P=0.093). Permutation testing confirmed that the observed difference in LPA improvement between cohorts (-0.51°) was not statistically significant (P=0.673), and post hoc analysis confirmed adequate power to detect a difference of 3.37°. Sensitivity analyses using ANCOVA, adjusting for baseline radiographic values and covariates, were concordant. CONCLUSION/CONCLUSIONS:ALIF provided superior regional and segmental lordosis but did not improve global alignment compared with TLIF. This study is the first to quantify the effect of ALIF versus TLIF on LPA, highlighting the limited impact of single-level fusion on global spinopelvic alignment.

BACKGROUND/UNASSIGNED:Surgical decompression of degenerative lumbar central stenosis, in older patients, has been shown to provide improved outcomes compared to conservative treatment. However, in elderly patients lacking instability, there still lacks a consensus on whether fusion is needed following decompression and whether the argument extends to cases involving multiple levels. METHODS/UNASSIGNED:Patients ≥ 65 years of age undergoing 2-4 multilevel laminectomies were included in the study. Intervertebral displacement was measured as the sagittal translation of each vertebral segment from L1 to S1 from flexion-extension films. Analyses of surgical and clinical outcomes were performed between decompression alone (MD) and decompression with fusion (MDF) groups through independent sample t-tests and Chi-square analyses. Propensity-score analysis was conducted to match patients from each group based on the number of levels decompressed and intervertebral stability. RESULTS/UNASSIGNED:= 0.075). At 1 year, MD and MDF groups experienced equivalent clinical outcomes, including radiculopathy, revision, and patient-reported measures. CONCLUSION/UNASSIGNED:Our data suggest that in elderly patients with similar baseline traits, multilevel decompression without fusion can provide improved perioperative outcomes with noninferior results at 1 year compared to with fusion.

PURPOSE/OBJECTIVE:Vertebral body tethering (VBT) offers a fusion-less alternative for adolescent idiopathic scoliosis (AIS) patients, with tether breakage being a common concern, particularly in single-row VBT. Limited data exist on double-row VBT's impact on tether breakage. This study evaluates a two-row vertebral body tethering (2RVBT) technique, comparing cases with and without broken tethers in patients with over 2 year follow-up. METHODS:A single-center, retrospective review (2019-2022) included AIS patients who underwent mini-open thoracoscopic-assisted 2RVBT. Inclusion criteria were idiopathic scoliosis < 65° flexible curves, residual post-operative curves < 30°, and ≥ 2 year follow-up. Patients were divided into broken-tether (BT) and non-broken-tether (NBT) groups. Radiographic measures included thoracic (T) and thoracolumbar (TL) Cobb angles, coronal balance, L5 tilt, and sagittal parameters. Tether breakage was defined by > 5° change in screw angulation, with or without associated loss of correction. RESULTS:Among 109 patients (NBT = 94, BT = 15), the overall tether breakage rate was 13.7%. The BT group had significantly larger pre-operative TL Cobb angles (53.4 ± 14.0° vs 43.7 ± 13.8°, p = 0.02), greater TL correction (- 36.2 ± 9.1° vs -2 3.7 ± 15.9°, p = 0.002), and higher post-operative coronal imbalance (21.2 ± 14.6 mm vs 11.9 ± 9.4 mm, p = 0.049). They also had significantly lower skeletal maturity (mean Risser stage 2.0 ± 1.1 vs 3.2 ± 1.3, p = 0.019; Sanders 4.0 ± 1.5 vs 5.4 ± 2.0, p = 0.019). Most broken tethers did not require revision, but some cases underwent re-tethering or fusion. CONCLUSION/CONCLUSIONS:Double tether constructs may reduce the rate of tether breakage following VBT. The main risk factors for tether breakage following double tether VBT are residual post-operative coronal imbalance, larger corrections in the lumbar spine, large rigid thoracic curves, and skeletal immaturity. Furthermore, most broken tethers did not require revision, which may indicate that curves maintained appropriate correction post-breakage due to the functional lifespan of double tether constructs. Although these are preliminary findings that must be supported with further multicenter studies that include single-tether constructs, these findings should be taken into consideration when indicating patients for VBT.

STUDY DESIGN/METHODS:Single-center retrospective study. OBJECTIVE:To evaluate the risks associated with postoperative kyphosis and loss of range of motion after cervical disc replacement (CDR). SUMMARY OF BACKGROUND DATA/BACKGROUND:One of the main benefits of CDR is that it maintains physiological range of motion (ROM) and lordosis while achieving decompression. However, some patients experience loss in segmental ROM or postoperative segmental kyphosis. This study analyzes the radiographic outcomes of these patients. METHODS:Adult patients who underwent CDR were included. The cohort was divided into patients with poor x-ray outcomes (PXR) and successful x-ray outcomes (SXR). The PXR group was defined as patients who had a loss in segmental ROM (≥11 degress decrease in Δ segmental ROM) after CDR and/or postoperative segmental kyphosis at the operative level at 2-year follow-up. Sagittal alignment and other measures were compared. RESULTS:A total of 151 (PXR=47; SXR=104) patients met the inclusion criteria. Pre- and postoperative segmental lateral Cobb angles were more kyphotic in the PXR group (3.5 vs. -1.4 degress, P<0.001; 2.6 vs. -5.6 degress, P<0.001). There was a larger Δ in segmental lateral Cobb angle in the SXR group (-4.2 vs. -0.9 degress, P<0.001). The PXR group had more flexion and less extension (11.3 degress vs. 6.5 degress, P<0.001; -2.2 vs. -6.1 degress, P=0.049). Segmental ROM loss was significant in the PXR group (-5.7 degress vs. 1.5 degress, P<0.001). Pre- and postoperative C2-C7 lateral Cobb angles were more kyphotic in the PXR group (-1.2 vs. -9.4 degress, P<0.001; -2.9 vs. -13.9 degress, P<0.001). Pre- and postoperative cSVA were larger in the PXR group (29.6 vs. 25.3 mm, P=0.047; 30.1 vs. 22.8 mm, P=0.004). Multiple variable regressions showed higher preoperative segmental lateral Cobb angle increased odds of SXR (OR=1.217, 95% CI: 1.083-1.369, P<0.001), while larger preoperative C2-C7 ROM decreased them (OR=0.970, 95% CI: 0.994-0.996, P=0.024). No significant differences in postoperative complications were observed. CONCLUSIONS:Patients with postoperative kyphosis or loss of ROM were more likely to have less segmental and regional C2-7 lordosis and a larger cSVA. Surgeons should consider these preoperative parameters when indicating CDR and counseling patients.

PURPOSE/OBJECTIVE:Clinical trials have studied the effects of curve magnitude and flexibility, age, and skeletal immaturity on the outcomes of VBT. No studies have assessed the effect of Lenke curve type on the outcomes of VBT. This study compares outcomes in patients who underwent VBT with Lenke type 1, 3, 5, and 6 curves. METHODS:Single center retrospective review of patients undergoing mini-open thoracoscopic-assisted two row vertebral body tethering (2RVBT) for the correction of AIS with a minimum 2-year follow-up were included. Patients were grouped by Lenke type, which yielded 4 groups; types 1, 3, 5, or 6. Analysis included preoperative demographic parameters, as well as radiographic and clinical outcome measures. RESULTS:156 2RVBT (Lenke 1, N = 61; Lenke 3, N = 35; Lenke 5, N = 37; Lenke 6, N = 23) patients met inclusion criteria. The mean preoperative apex Cobb angle in the Lenke type 1, 3, 5, and 6 groups were 50.2 ± 9.1, 50.5 ± 10.1, 45.0 ± 8.6, and 49.0 ± 10.8, respectively. This corrected to 21.2 ± 10.2, 19.2 ± 8.5, 13.6 ± 7.2, 18.5 ± 8.3 in Lenke type 1, 3, 5, and 6 groups, respectively, demonstrating that Lenke type 5 saw greatest correction following 2RVBT. With regards to revision recommendation following tether breakage, Lenke type 3 curves were most frequently indicated for fusion, whereas Lenke type 1 curves were most frequently not indicated for revision surgery. CONCLUSION/CONCLUSIONS:Lenke type 5 curves are the most amenable to correction via 2RVBT, as evident by their lower post-operative apex Cobb angles and lowest rate of recommendation for revision to posterior spinal fusion.