Faculty Bibliography

BACKGROUND AND OBJECTIVES/OBJECTIVE:Thoracolumbar spinal deformity frequently coexists with cervical spine deformity (CD) and lower extremity osteoarthritis (OA), complicating management and compounding functional disability. This study investigates the additive burden of these conditions on patient-reported outcome measures (PROMs). METHODS:This retrospective analysis assessed primary thoracolumbar deformity patients undergoing corrective surgery. Demographics, spinopelvic alignment, and PROMs were characterized. Severe CD was defined by ≥1 Ames criterion. Hip (HOA) and knee (KOA) OA were defined as Kellgren-Lawrence grade ≥3. Hierarchical regression and mixed-effects models evaluated the incremental and longitudinal impacts of these conditions on PROMs. RESULTS:Among 816 patients (mean age 60.4 years, 67.1% female), 24.8% had CD, 43.7% HOA, and 40.4% KOA at baseline. Regression revealed that HOA worsened Oswestry Disability Index (ODI) total (R2 = 0.056, P = .008), ODI Walking (R2 = 0.121, P <.001), Patient-Reported Outcomes Measurement Information System (PROMIS) Physical Function (R2 = 0.108, P = .013), and Veterans RAND 12-Item Health Survey (VR-12) Physical Component Score (PCS) (R2 = 0.098, P = .022). KOA primarily affected pain and psychosocial outcomes, including ODI Pain (R2 = 0.033, P = .001), PROMIS Depression (R2 = 0.018, P = .002), Scoliosis Research Society-22 Mental (R2 = 0.033, P = .004), and VR-12 Mental Component Score (R2 = 0.023, P = .025). CD contributed to ODI (R2 = 0.063, P = .018) and Scoliosis Research Society-22 Activity (R2 = 0.044, P = .032). Mixed-effects models showed improvements in all PROMs from baseline to 2-year follow-up (P <.001). However, HOA reduced improvements in ODI (3.41 points, P = .009), PROMIS Physical Function (1.37 points, P = .009), and VR-12 PCS (2.21 points, P = .003). KOA was associated with reduced walking tolerance (ODI Walking: 0.21 points, P = .020) and increased psychological burden (PROMIS Anxiety: 1.71 points, P = .007; VR-12 MCS: 2.01 points, P = .027). CD affected ODI Walking (0.51 points, P = .007) and VR-12 PCS (3.19 points, P = .043). CONCLUSION/CONCLUSIONS:HOA patients undergoing deformity correction have worse preoperative physical disability and impaired postoperative functional recovery. KOA is associated with greater psychological burden. Severe CD has smaller physical impact. These findings highlight the need for individualized, multidisciplinary management strategies, with particular emphasis on early identification and targeted intervention for hip pathology to optimize outcomes.

STUDY DESIGN/METHODS:Retrospective cohort. OBJECTIVE:The ISSG-AO Spinal Deformity Complication Classification System (SDCCS) predicts Diagnosis Related Group (DRG) coding and cost. BACKGROUND:Inconsistent definitions of complications contribute to variation in reported surgical complication rates. Incorrect complication reporting can lead to over or under DRG reimbursement. The ISSG-AO SDCCS provides improved complication reporting reproducibility and may help predict complication costs. METHODS:ASD patients were grouped into: DRG without complication or comorbidity (CC) or Major CC (MCC) (DRGs 455 & 458), with CC (DRGs 454 & 457), and with MCC (DRGs 453 & 456). Complications were graded by intervention severity per ISSG-AO system: grade 0 (none), 1 (mild-e.g., med change), 2 (moderate-e.g., ICU), 3 (severe-e.g., reoperation). Cost were based on Medicare inpatient prospective payment system (IPSS, Medicare Allowable rate). A multinomial logistic model identified key predictors of DRG assignment by complication grades. RESULTS:Of the 675 patients, 14% were in DRGs without CC/MCC, 71% in DRGs with CC, and 15% were DRGs with MCC. Patients with complications requiring intervention mostly fell into the higher DRG categories (97%). Patients who received an intervention are approximately 6.75 (2.01-22.75, P<.0021) times more likely to be classified under DRG with CC and 15.72 (95% CI, 4.23-58.45, P<.0001) times more likely to be classified with DRG with MCC compared to those who did not receive an intervention. Each unit increase in Edmonton Frailty Score raises the odds of being in DRG with MCC by 1.24 (95% CI 1.04-1.48, P 0.017). Similar trends were seen for OR time and LOS. Reimbursement showed incremental increase from $49.5K to $56K to $70K across DRG categories. CONCLUSIONS:Patients with elevated ISSG-AO scores are more likely to be categorized into higher DRGs, experience extended lengths of stay and generate greater healthcare expenditures. The ISSG-AO SDCCS predicts DRG thereby helping standardize complication reporting.

OBJECTIVE:While health-related quality of life (HRQOL) measures have been extensively quantified in cervical deformity (CD), this clinical dimension has not yet been fully integrated into understanding CD radiographic subtypes prior to surgery. The aim of this study was to identify distinct patterns of HRQOL deficits among patients with CD by focusing on clinical scores and to examine the association of these patterns with radiographic morphotypes of CD. METHODS:This was a retrospective analysis of a prospective multicenter database of patients with CD aged 18 years or older. Patient-reported outcome measures consisted of the Neck Disability Index (NDI), modified Japanese Orthopaedic Association (mJOA) scale, and Swallowing Quality of Life (SWAL-QOL) questionnaire. After performing a principal component analysis on the individual questions of the NDI, mJOA, and SWAL-QOL, 4 factors with eigenvalues > 1 were retained and included in a cluster analysis to assign patients into homogeneous groups of outcomes. Moreover, a subgroup of patients with severe deformity was described and analyzed. RESULTS:Overall, 134 patients (59% female, mean age ± SD 60.9 ± 10.8 years) were included in this analysis. The mean HRQOL scores were NDI, 49.1 ± 17.6; mJOA, 13.5 ± 2.7; and EQ-5D, 0.7 ± 0.1). The factor analysis involving NDI, SWAL-QOL, and mJOA revealed 4 clusters. Cluster A represented patients with a predominant sleep problem. Cluster B was patients with the lowest neck disability. Cluster C represented the most disabled patients in terms of dysphagia and neck disability. Cluster D represented patients with myelopathy. Among the 71 patients with severe deformity, the distribution of cervical morphotypes significantly differed across the 4 clusters of disability (p = 0.009). Cluster C mainly consisted of patients with cervicothoracic deformity (66.7%, p = 0.002). Cluster D had a large proportion of patients (66.7%) with focal deformity (p = 0.007). In clusters A and B, 57.9% and 46.4% of patients, respectively, presented with "flat neck" deformity (p = 0.02). CONCLUSIONS:Distinct patterns of HRQOL deficits were observed across a heterogeneous population of patients with CD, and these patterns were associated with specific radiographic morphotypes. These findings provide a framework for the next generation of CD classification, wherein HRQOL measures are combined with radiographic parameters.

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.

OBJECTIVE:The aim of this study was to determine if there are any specific procedural, demographic, and/or radiographic factors that are associated with an improved postoperative lower extremity (LE) motor score (LEMS) among patients with adult spinal deformity (ASD) and abnormal baseline LEMS undergoing surgical correction. METHODS:Patients with ASD enrolled in an observational prospective study from 2018 to 2023 at 13 spinal deformity centers in North America were queried. Eligible participants met at least one of the following radiographic and/or procedural inclusion criteria: pelvic incidence minus lumbar lordosis mismatch ≥ 25°, T1 pelvic angle ≥ 30°, SVA ≥ 15 cm, thoracic scoliosis ≥ 70°, thoracolumbar scoliosis ≥ 50°, global coronal malalignment ≥ 7 cm, underwent 3-column osteotomy (3CO), spinal fusion ≥ 12 levels, and/or age ≥ 65 years with ≥ 7 levels of instrumentation. Patients with a baseline abnormal LEMS were dichotomized based on whether the LEMS improved or deteriorated from baseline by the 6-week postoperative visit. Patients with a maintained LEMS by 6 weeks compared with baseline were excluded. Patient and operative characteristics were compared through bivariate analyses to assess differences in treatment. A multivariable logistic regression model was built to discern independent factors associated with improved LEMS while controlling for potential confounders. RESULTS:Of 121 patients (77 female, mean age 62.9 years) included in the study, 109 (90.1%) improved and 12 (9.9%) experienced further deterioration from baseline to 6 weeks. Both groups had similar baseline LEMS by laterality and per nerve root. The groups were similar in age, sex, comorbidities, baseline LEMS, BMI, surgical indication, number of instrumented levels, estimated blood loss, operating room time, and hospital length of stay (p > 0.05). No differences in radiographic parameters at baseline and 6 weeks were observed aside from patients whose score had deteriorated experiencing greater change in the L1 pelvic angle (∆L1PA) (-8.0° ± 8.3° vs -1.6° ± 7.6°, p = 0.0413). Despite having similar frequencies of lumbar decompressions performed across a similar number of levels, patients whose conditions had deteriorated at 6 weeks had fewer lumbar posterior column osteotomies (PCOs) performed (50% vs 82.6%, p = 0.0169). No differences in in the frequency and number of 3COs performed were observed. Patients whose score had deteriorated experienced greater intraoperative neurophysiological monitoring (IONM) changes (41.7% vs 8.3%, p = 0.0050), all of which were motor deficits. Controlling for ∆L1PA and IONM changes revealed lumbar PCOs to be an independent driver of improved LEMS (OR 4.99 [95% CI 1.05-23.70]), with excellent model performance (p = 0.0031, area under the receiver operating characteristic curve of 0.77, Hosmer-Lemeshow goodness-of-fit test p = 0.3017). CONCLUSIONS:Performing lumbar decompressions alone might not be enough to improve LE weakness in patients with ASD and preoperative motor impairment, while the use of PCO was beneficial for improvement. Thus, more aggressive and thorough decompressions afforded by a combined approach of lumbar PCOs and decompression should be considered in this patient population to optimize postoperative motor strength.

BACKGROUND/UNASSIGNED:open or minimally invasive (MIS) laminectomy using the American College of Surgeons' National Surgical Quality Improvement Program (ACS-NSQIP) database. METHODS/UNASSIGNED:Using the ACS-NSQIP database from 2017 to 2022, Current Procedural Terminology (CPT) code of 63030 or 62380 were used to filter the dataset between open/tubular retractor-based and endoscopic single-level lumbar decompression cases, respectively. Overall, as collected, the endoscopic group consisted of 336 patients and the non-endoscopic group had 55,111 patients. The groups were compared to evaluate the patient characteristics and adverse events within 30 days after their operation. Outcome measures compared were operative time, length of stay (days), adverse outcomes [superficial infection, deep infection, organ/space infection, wound dehiscence, pneumonia, unplanned intubation, pulmonary embolism, ventilator >48 hours, progressive renal insufficiency, acute renal failure, urinary tract infection, stroke/cerebrovascular accident (CVA) accident, cardiac arrest, myocardial infarction, blood transfusion, deep vein thrombosis (DVT), sepsis, and septic shock], 30-day readmission, return to operating room (OR). RESULTS/UNASSIGNED:4.8%, P=0.01), with significantly lower rate of blood transfusions (P<0.05) compared to the non-endoscopic group. CONCLUSIONS/UNASSIGNED:Patients who underwent endoscopic lumbar decompression demonstrated a significantly lower rate of total adverse events and significantly lower rate of blood transfusions compared to their counterparts. This data from the ACS-NSQIP supports the reported benefits of endoscopic technique in the current literature. As endoscopic surgery becomes more widely utilized throughout the United States, more data will become available for further studies.

BACKGROUND AND OBJECTIVES/OBJECTIVE:The concept of upper cervical (C0-C2) extension reserve (ER) capacity, ER relaxation, and their impact on outcomes following surgical correction of adult cervical deformity (ACD) has not been extensively studied. We aimed to evaluate the impact of upper cervical ER on postoperative disability and outcomes. METHODS:Patients with ACD, from a retrospective cohort study of a prospectively collected multicenter database, undergoing subaxial cervical fusion with 2-year (2Y) follow-up data were included. ER was defined as: ΔC0-C2 sagittal Cobb angle between neutral and extension. Relaxation of ER was defined as the ER mean in those that met all ideal thresholds in radiographic parameters for Passias et al CD modifiers. We used multivariable logistic regression to adjust for confounding, with conditional inference tree approaches used to determine thresholds that affect postoperative ER resolution on patient-reported outcomes. RESULTS:A total of 108 patients with ACD met inclusion. Preoperative C0-C2 ER was 8.7° ± 9.0°, and at last follow-up was 10.3° ± 11.1°. Preoperatively 29% of the cohort had adequate ER, whereas 60% had improved ER postoperatively, with 50% achieving adequate ER by 2Y. Lower ER correlated with greater CD (P < .05). Preoperatively, greater ER had lower Neck Disability Index (P < .001). Controlled analysis found improved ER to have a greater likelihood of achieving Neck Disability Index minimum clinically important difference (odds ratio 6.94, [1.378-34.961], P = .019). In those with inadequate ER at baseline, the preoperative C2-C7 of < -18° and T1 slope-cervical Lordosis mismatch of >59° for T1 slope-cervical Lordosis mismatch was predictive of ER resolution. In those with preoperative C2-C7 >-18°, a T1PA of >13° was predictive of postoperative return of ER (all P < .05). Surgical correction of C2-C7 by > 16° from baseline was found to be predictive of ER return. CONCLUSION/CONCLUSIONS:Increased preoperative use of the C0-C2 ER in CD was associated with worse baseline regional and global alignment and adversely affected health-related measures. Most of the patients had ER relaxation postoperatively. In those who didn't, however, there was a decreased likelihood of achieving satisfactory outcomes.

INTRODUCTION/BACKGROUND:With the rapid increase in the use of robotic-assisted spine surgery (RASS), reports describing complications have inevitably emerged. This study builds on previous work done to identify, characterize, and classify potential sources of error in spine surgery performed with enabling technology in the operating room. The goal of this study is to leverage expert opinion to develop a set of best practice guidelines that can be employed to minimize complications and optimize patient safety, specifically as it relates to RASS. METHODS:After assembling a group of attending spine surgeons experienced in the use of RASS across the country, formal consensus regarding the best practices was developed using the Delphi method and nominal group technique. After a review of the relevant literature and evidence, an initial survey of study group members (n=12) helped frame potential areas for investigation. Statements were subsequently edited, removed, or elaborated upon during four iterative rounds of live discussion with the opportunity for panelists to propose new guidelines at any point in the process. Respondents were able to suggest modifications and refine the statements until consensus, defined as ≥ 80% agreement, was achieved. RESULTS:After a three-round iterative survey and video conference Delphi process, followed by an in-person meeting at the Summit for Safety in Spine Surgery, consensus was achieved on 27 best practice guideline statements. This BPG had the key focus areas of 1) general protocols, 2) screw planning/execution, 3) optimization of surgical technique, and 4) areas for robotic improvement. (available at https://safetyinspinesurgery.com/ ). CONCLUSION/CONCLUSIONS:This work provides expert insight into the best practices for minimizing errors in RASS with the presentation of 27 recommendations that can serve to reduce practice variability, optimize safety, and guide future research.

PURPOSE/OBJECTIVE:To determine if iatrogenic posterior translation (UIV SPi) at the upper instrumented vertebrae (UIV) is associated with increased mechanical complications and secondarily to generate and validate a UIV SPi threshold for increased complications. METHODS:Two patient databases were utilized: one for generating a UIV SPi threshold and another for validation. Patients with a UIV between T8-L1 and a LIV at ilium were included. A receiver operating curve (ROC) curve analyses was performed to generate a threshold that predicted proximal junctional complications. This UIV SPi angle (-16.0°) was rounded to -15.0° for practical clinical use and validated in a separate cohort. Patients were stratified as above (most translated, MT) or below (least translated, LT) the threshold for comparative demographic and outcomes analyses. RESULTS:Generation of the threshold on 192 patients (122 LT, 70 MT) revealed that the MT group had higher absolute postoperative UIV SVA (MT=-56.1 ± 23.1 mm vs. LT=-10.4 ± 31.8 mm, p < 0.001), higher PT (25.7° vs. 19.3°, p < 0.001), and 2.8-5.8 times greater odds of postoperative proximal junctional complications at 2-years (p < 0.05). Validation on 135 patients (95 LT, 40 MT) revealed that the MT group had 11.7 times greater odds of radiographic PJK and had 4.5 times greater odds of all-cause reoperations (p < 0.05). CONCLUSION/CONCLUSIONS:Patients with UIV posterior translation, despite similar PI-LL and T1PA, exhibit a high PT and experience higher odds of proximal junctional complications. Our findings support limiting the UIV SPi to < 15° of posterior translation to mitigate postoperative mechanical complications. LEVEL OF EVIDENCE/METHODS:IV.