BACKGROUND AND OBJECTIVES:In patients undergoing adult spinal deformity surgery, we aimed to evaluate the relationship between rural residence and: (1) perioperative outcomes, (2) postoperative alignment, and (3) complications. METHODS:A retrospective cohort study (2009-2023) was performed for patients with the following inclusion criteria: ≥5-level fusion, sagittal/coronal deformity, and 2-year follow-up. Primary exposure was rural residence based on Economic Research Service designated Rural-Urban Commuting Area codes: 1 to 6-urban, 7 to 10-rural. Primary outcomes were: (1) perioperative outcomes, (2) postoperative alignment, including sagittal vertical axis, coronal vertical axis, and L1-pelvic angle within target range, and (3) complications. Multivariable regression controlled for age, sex, body mass index, preoperative sagittal vertical axis/coronal vertical axis, and operative time. RESULTS:Of 288 patients, 36 (13%) were rural residents. Rural patients had a higher body mass index (32 ± 9 vs 28 ± 6, P = .011) and diabetes rate (33% vs 17%, P = .024). Preoperatively, rural patients had lower hematocrit (35.4 ± 6.5 vs 37.4 ± 5.2, P = .048) and required more frequent (78% vs 58%, P = .023; odds ratio = 3.1, 95% CI: 1.1-8.5, P = .031) and greater (4 ± 5 vs 2 ± 4 units, P = .019) intraoperative transfusions. Postoperatively, rural residents had higher sagittal vertical axis ≥5 cm (69% vs 48%, P = .037; β = 16.1, 95% CI: 0.0-32.2, P = .050), with no significant association with postoperative coronal malalignment (25% vs 19%, P = .688). No difference was seen in rates of complications, or reoperation. CONCLUSION:In patients undergoing adult spinal deformity surgery, rural residence was independently associated with increased intraoperative blood transfusions and worse postoperative sagittal alignment. These findings suggest that socioeconomic and geographic factors may play a role in surgical outcomes, potentially because of disparities in preoperative health status and access to perioperative care.

BACKGROUND CONTEXT Proximal alignment in lower thoracic-to-pelvis fusion influences the risk of proximal junctional kyphosis and failure (PJK/F), though the optimal alignment target remains unclear. PURPOSE To evaluate whether postoperative upper instrumented vertebra–L1 (UIV–L1) Cobb angle orientation is associated with PJK/F in patients undergoing lower thoracic-to-pelvis fusion. STUDY DESIGN/SETTING Retrospective cohort study. PATIENT SAMPLE Patients undergoing adult spinal deformity surgery between 2009 and 2023 with lower thoracic UIV (T9–T12), instrumentation to the pelvis, sagittal or coronal malalignment, and ≥2-year follow-up. OUTCOME MEASURES Primary outcome was PJK/F, defined as UIV/UIV+2 angle ≥10° and ≥10° increase from preoperative measurement. Secondary outcomes included reoperation for mechanical complications and other mechanical complications (rod fracture, pseudarthrosis, implant failure). METHODS The primary exposure was postoperative UIV–L1 sagittal Cobb angle. Alignment was categorized as neutral (−3° to 3°) or non-neutral. Non-neutral alignment was further stratified into kyphotic (>3°) and lordotic (<−3°). Subgroup analysis was performed based on pelvic incidence (PI), dichotomized at 50°. Multivariable regression controlled for age, sex, body mass index, and UIV level. RESULTS Among 90 patients (mean age 68.6 ± 10.6 years; 72% female), UIV distribution was T9 (18%), T10 (51%), T11 (19%), and T12 (12%). The median postoperative UIV–L1 Cobb angle was 9.0° (IQR 4.0°–19.0°), with 3.3% lordotic, 20.0% neutral, and 76.7% kyphotic alignment. Patients with neutral alignment had lower rates of PJK/F compared with non-neutral alignment (16.7% vs 43.1%; p=0.039), with no differences in reoperation (27.8% vs 22.2%; p=0.618) or other mechanical complications (16.7% vs 31.9%; p=0.201). On multivariable analysis, non-neutral alignment independently increased the risk of PJK/F (OR 5.4; 95% CI 1.2–24.9; p=0.029). When stratified further, neutral alignment demonstrated the lowest PJK/F rates, while lordotic alignment had the highest (16.7% vs 40.6% vs 100.0%; p=0.014 for neutral vs kyphotic vs lordotic). No differences were observed in reoperation or other mechanical complications among these groups. CONCLUSIONS Neutral UIV–L1 alignment is associated with the lowest risk of proximal junctional kyphosis and failure following lower thoracic-to-pelvis fusion. Deviation toward either kyphosis or lordosis increases risk, with lordotic alignment demonstrating the highest risk. Achieving neutral alignment may represent a practical, modifiable intraoperative target to reduce PJK/F risk. FDA Device/Drug Status This abstract does not discuss or include any applicable devices or drugs.

Study Design. Cross-sectional survey and retrospective-cohort study (2010-21) Objectives. We sought to:1) create a novel epidural cauda-equina compression (ECEC) grading system, 2) determine its inter/intrarater reliability, and 3) report its ability to predict preoperative neurologic status. Summary of Backgrounds Data. While metastatic epidural spinal-cord compression is well characterized, ECEC remains poorly understood. Methods. Patients undergoing ECEC surgery were included. Severity was graded on axial MRI using a novel 4-point scale: Grade-0 =Bone-only; Grade-1 =Thecal sac indented<50% effaced; Grade-2 =≥50% thecal sac effaced; Grade-3 =Entire thecal sac effaced, no cerebrospinal fluid seen; +F modifier signified foraminal stenosis. Primary outcomes were inter/intrarater reliability, and the score’s ability to predict baseline neurologic deficits. Reliability was assessed among spine surgeons, trainees, and radiation oncologists using intraclass correlation coefficient. Results. The survey included 9 spine-attendings, 7 trainees, and 4 radiation oncologists. Among 45 patients (mean age:61.6±10.6 y; 64.4% male), 15.5% each had Grade-1/2 compression, while 68.9% had Grade-3; foraminal stenosis was present in 82.2%. Grade 0-3: Overall inter/intrarater reliability was good at 0.635(95%CI:0.412–0.776) and 0.676(95%CI:0.503–0.810), with similar performance among spine-attendings (inter/intrarater:0.611;0.662), trainees (inter/intrarater:0.685;0.707), and radiation oncologists (inter/intrarater:0.634;0.679). Sensory deficits (28.6% vs. 28.6% vs. 16.1%, P =0.627), motor deficits (71.4% vs. 57.1% vs. 35.5%, P =0.171) and bowel/bladder disturbances (0% vs. 28.6% vs. 19.4%, P =0.346) were similar across grades. +F Modifier: Overall inter/intrarater reliability were poor at 0.350 (95%CI:0.180–0.505) and 0.391(95%CI:0.219–0.555), with fair reliability for spine-attendings (inter/intrarater:0.421;0.485), and trainees (inter/intrarater:0.414;0.443), and poor for radiation oncologists (inter/intrarater:0.259;0.299). Baseline neurological status showed no association with foraminal stenosis. Conclusion. The novel ECEC grading system provides a reliable framework for characterizing metastatic ECEC, demonstrating good reliability for Grades-0–3 across spine surgeons, trainees, and radiation oncologists. Although compression grade was not associated with neurologic deficits, bowel/bladder deficit rates were non-significantly higher in Grades-2/3. Conversely, foraminal-modifier’s poor reliability underscores limitations of static MRI in assessing foraminal stenosis. Overall, ECEC scale may enhance communication in describing neoplastic ECEC.

BACKGROUND AND OBJECTIVES: Prolonged intubation is an unwanted occurrence after adult spinal deformity (ASD) surgery, yet its risk factors are poorly understood. For patients undergoing ASD surgery, we sought to: (1) report the rate of intubation until postoperative day 1 (POD 1), (2) create a scoring system to predict it, and (3) externally validate the scoring system. METHODS: A retrospective cohort study (2009-2021) was performed for patients undergoing ASD surgery. Primary outcome was prolonged intubation (POD 1 or beyond). Univariate logistic regression were performed. External validation was performed using an independent cohort. RESULTS: Among 233 patients, 36 (15%) remained intubated until at least POD 1. These patients were older (70 vs 62 years, P = .001), had longer surgeries (543 vs 398 minutes, P < .001), late procedure end times (18:34 vs 15:59, P < .001), change of anesthetists (56% vs 31%, P = .04), greater blood loss (2809 vs 1207 mL, P < .001), and required intraoperative blood transfusion (89% vs 54%, P < .001). For every extra 30 minutes the case continued, odds of prolonged intubation increased by 22% (odds ratio = 1.2, 95% CI: 1.1-1.3, P < .001). The final scoring system included: age 60 years and older, intraoperative blood transfusion, operative time >7 hours, change of anesthetists, and procedure close time after 17:00. Receiver operating characteristic analysis revealed a cutoff of >4 points as a predictor of prolonged intubation (area under the curve = 0.8, 95% CI: 0.8-0.9, P < .001, sensitivity = 89%, specificity = 70%). On external validation, the score demonstrated moderate discriminative ability (area under the curve = 0.7). At the threshold of 4, sensitivity was 91%, and specificity was 26%. CONCLUSION: Approximately 15% ASD surgery patients remained intubated through POD 1. An 8-point risk score incorporating age 60 years and older, operative time ≥7 hours, intraoperative transfusion, change of anesthetists, and procedure end time after 17:00 demonstrated strong discrimination in the derivation cohort and moderate, high-sensitivity performance on external validation. Use of this score in collaboration with anesthesia teams may enable early risk stratification and targeted perioperative planning.

Achieving target L1-pelvic-angle (L1PA) is heavily influenced by segmental lordosis changes during adult spinal deformity (ASD) surgery. Understanding the effect of changing each lordotic segmental level on L1PA will aid in preoperative planning and intraoperative alignment assessment in ASD. In patients undergoing ASD surgery, we aimed to evaluate the impact of segmental lordosis changes on postoperative L1PA. A retrospective cohort study (2009-24) was performed for ASD surgery patients. Inclusion criteria were: ≥5-level fusion and sagittal/coronal deformity. Primary exposure variable was change in segmental lordosis at each lumbar level. Primary outcome was the change in L1PA. Multivariable regression controlling for preoperative and change in segmental lordosis at each level was performed. Of 180 patients (mean age:59 ± 19 years, 32

BACKGROUND CONTEXT A dedicated bone optimization clinic for adult spinal deformity (ASD) patients may be cost-effective by reducing reoperations and offsetting the added costs of anabolic agents. PURPOSE To determine the cost-effectiveness of a dedicated bone optimization clinic for ASD patients with osteopenia/osteoporosis, weighing clinic and medication costs against savings from avoided reoperations. STUDY DESIGN/SETTING Retrospective cohort study. PATIENT SAMPLE A retrospective cohort (2009–2023) of osteopenic/osteoporotic patients undergoing ASD surgery, grouped by pre- and postimplementation of a bone optimization clinic (2009–2019 vs 2020–2023). OUTCOME MEASURES N/A. METHODS Surgical costs were derived from total inpatient costs. Medication costs were calculated using Medicare pricing and treatment duration. Revision surgery costs were obtained from institutional data. A decision-tree model evaluated cost-effectiveness and break-even thresholds, with all costs adjusted to 2025 US dollars. RESULTS Of 126 patients, 91 (72%) were preclinic and 35 (28%) postclinic. Reoperation rates were 44% preclinic versus 6% postclinic (p<0.001). Median initial surgery cost was $132,104, and revision cost was $111,468. Anabolic therapy averaged $30,772 per patient. Cost modeling showed savings of $11,700 per patient over 2 years. Sensitivity analysis showed cost-effectiveness unless medication costs increased by 39% or reoperation benefit dropped below 28%. National projections suggest potential savings of over $112 million annually. CONCLUSIONS A bone optimization clinic for ASD patients is cost-effective, with reduced reoperations outweighing treatment costs. Such clinics may significantly reduce healthcare costs and improve outcomes. FDA Device/Drug Status This abstract does not discuss or include any applicable devices or drugs.

OBJECTIVE:Venous sinus stenting (VSS) has emerged as a promising and less invasive treatment alternative to CSF diversion for patients with idiopathic intracranial hypertension (IIH). Fulminant IIH (fIIH) is a rare manifestation of IIH, affecting 2%-3% of IIH patients and characterized by rapid, progressive, and severe visual loss. Outcomes following different treatment modalities for fIIH remain unclear. METHODS:A dual-center retrospective cohort study was done comparing patients who underwent VSS or ventriculoperitoneal shunting (VPS) for fIIH over a 5-year time frame, defined as rapid visual loss secondary to IIH refractory to medical management. Patient demographic characteristics, baseline symptom characteristics focusing on headache and visual decline, operative parameters, postoperative complications, and outcomes were collected. The decision to proceed with VSS or VPS was based on surgeon discretion and institutional preference. Data were analyzed using the bivariate t-test or chi-square test as appropriate, and multivariate logistic regression was used to identify significant predictors. RESULTS:A total of 39 patients who underwent treatment for fIIH were identified, of whom 46% (n = 18) underwent VPS and 54% (n = 21) underwent VSS. The VSS cohort included more females (100% vs 76%, p = 0.03), otherwise no differences were seen in age, BMI, rate of preoperatively diagnosed headache disorder or psychiatric disorder, acetazolamide usage, preoperative papilledema grade, preoperative average visual acuity, or preoperative opening pressure. On univariate regression, VSS was associated with improved headache reduction (58% vs 25%, p < 0.001) as well as decreased headache recurrence (27% vs 65%, p = 0.03). Both cohorts showed a high rate of improvement in papilledema postoperatively (93.3% for VSS vs 92.8% for VPS, p > 0.99), and there was no significant difference in the rates of postoperative visual acuity improvement (83% for VSS vs 50% for VPS, p = 0.17). VPS patients were more likely to have reductions in acetazolamide usage postoperatively (85% vs 22%, p = 0.001). No postoperative hemorrhages, access site complications, or stent thromboses were observed. On multivariate regression, no significant predictors of improvement in headache severity, papilledema, or visual acuity were observed. CONCLUSIONS:Among patients presenting with fIIH, VSS is comparable to VPS with respect to visual outcomes defined as improvement in papilledema. Larger randomized studies are required to determine differences in outcomes between VSS and VPS in this subpopulation of IIH patients.

STUDY DESIGN:Cross-sectional survey and retrospective-cohort study (2010-21). OBJECTIVES:We sought to:1) create a novel epidural cauda-equina compression (ECEC) grading system, 2) determine its inter/intrarater reliability, and 3) report its ability to predict preoperative neurologic status. SUMMARY OF BACKGROUNDS DATA:While metastatic epidural spinal-cord compression is well characterized, ECEC remains poorly understood. METHODS:Patients undergoing ECEC surgery were included. Severity was graded on axial MRI using a novel 4-point scale:Grade-0=Bone-only; Grade-1=Thecal sac indented<50% effaced; Grade-2=≥50% thecal sac effaced; Grade-3=Entire thecal sac effaced, no cerebrospinal fluid seen; +F modifier signified foraminal stenosis. Primary outcomes were inter/intrarater reliability, and the score's ability to predict baseline neurologic deficits. Reliability was assessed among spine surgeons, trainees, and radiation oncologists using intraclass correlation coefficient. RESULTS:The survey included 9 spine-attendings, 7 trainees, and 4 radiation oncologists. Among 45 patients (mean age:61.6±10.6 y; 64.4% male), 15.5% each had Grade-1/2 compression, while 68.9% had Grade-3; foraminal stenosis was present in 82.2%. Grade 0-3: Overall inter/intrarater reliability was good at 0.635(95%CI:0.412-0.776) and 0.676(95%CI:0.503-0.810), with similar performance among spine-attendings (inter/intrarater:0.611;0.662), trainees (inter/intrarater:0.685;0.707), and radiation oncologists (inter/intrarater:0.634;0.679). Sensory deficits (28.6% vs. 28.6% vs. 16.1%,P=0.627), motor deficits (71.4% vs. 57.1% vs. 35.5%,P=0.171) and bowel/bladder disturbances (0% vs. 28.6% vs. 19.4%,P=0.346) were similar across grades. +F Modifier: Overall inter/intrarater reliability were poor at 0.350 (95%CI:0.180-0.505) and 0.391(95%CI:0.219-0.555), with fair reliability for spine-attendings (inter/intrarater:0.421;0.485), and trainees (inter/intrarater:0.414;0.443), and poor for radiation oncologists (inter/intrarater:0.259;0.299). Baseline neurological status showed no association with foraminal stenosis. CONCLUSION:The novel ECEC grading system provides a reliable framework for characterizing metastatic ECEC, demonstrating good reliability for Grades-0-3 across spine surgeons, trainees, and radiation oncologists. Although compression grade was not associated with neurologic deficits, bowel/bladder deficit rates were non-significantly higher in Grades-2/3. Conversely, foraminal-modifier's poor reliability underscores limitations of static MRI in assessing foraminal stenosis. Overall, ECEC scale may enhance communication in describing neoplastic ECEC.

IntroductionVenous sinus stenting (VSS) is an effective, less invasive alternative to ventriculoperitoneal shunting (VPS) for idiopathic intracranial hypertension (IIH). While efficacy is comparable, with some evidence favoring VSS for headache control, perioperative costs remain under-characterized due to reliance on reimbursement rates rather than actual expenditures.ObjectiveTo compare the perioperative cost of elective VSS and VPS for IIH, including outpatient workup and follow-up costs, using detailed institutional cost data.MethodsWe retrospectively analyzed IIH patients treated with VSS or VPS from 2017 to 2022 at a single center. All IIH-related costs were captured from 90 days pre-op through 90 days post-op and categorized as fixed (e.g. OR staff) or variable (e.g. supplies). Patients with fulminant IIH or unrelated elective procedures were excluded. Comparisons used Mann-Whitney U and Fisher's exact tests (p < 0.05).ResultsForty-three patients met criteria (VSS n = 19, VPS n = 24), with no significant differences in age, body mass index, papilledema, opening pressure, or pulsatile tinnitus. Preoperative costs were significantly higher for VSS (median $14,951 [IQR 10,835-16,043] vs $4767 [1, 293, 410-11]; p = 0.008), including both variable (p = 0.008) and fixed (p = 0.015) cost components. Surgical admission costs were similar between groups (p = 0.403), as were postoperative costs (p = 0.509). Total 180-day costs remained significantly higher for VSS ($38,576 [011-43, 36, 590]) compared to VPS ($31,509 [25, 208-37, 342]; p = 0.001).ConclusionVSS incurs higher preoperative and total costs than VPS. Streamlining VSS workup may improve value. Further studies should assess downstream cost avoidance to determine long-term cost-effectiveness.

INTRODUCTION: Several different mechanisms contribute to proximal junctional kyphosis/failure (PJK/F) in adult spinal deformity (ASD) surgery, each of varying severity. METHODS: A single-institution, retrospective cohort study was performed for patients undergoing ASD surgery from 2009-21. The primary outcome was the mechanism of PJK/F. Secondary outcomes included time to PJK/F, PJA, reoperation, and neurologic deficit. RESULTS: Among 238 patients undergoing ASD surgery, 113 (47.5%) developed PJK/F with the following overlapping mechanisms: screw pullout (N=8, 7.1%), UIV fracture (N=17, 15.0%), UIV+1 fracture (N=9, 8.0%), screw haloing (N=14, 31.0%), fracture dislocation (N=13, 11.5%), supradjacent disc degeneration with or without listhesis (N=35, 31.0%), and radiographic kyphosis only (N=17, 15.0%). Mean time to diagnose PJK/F was 23.1±20.6m as follows: screw pullout (time to diagnosis=23.9m, PJA=19.9º), UIV fracture (23.8m, 25.6º), UIV+1 fracture (21.8m, 28.0º), screw haloing (21.8m, 19.0º), fracture dislocation (18.7m, 37.9º), disc degeneration (23.5m, 25.6º), and radiographic kyphosis only (25.9m, 19.5º) (p=0.986, p<0.001). Reoperation occurred in 45 (39.8%) patients as follows: 6/8 (75.0%) screw pullout, 6/17 (35.2%) UIV fracture, 4/9 (44.4%) UIV+1 fracture, 9/14 (64.3%) screw haloing, 6/13 (46.1%) fracture dislocation, 9/35 (25.2%) disc degeneration, and 7/17 (41.1%) radiographic kyphosis only (p=0.068). Neurologic Deficits occurred in 15 (13.3%) patients. CONCLUSIONS: Supradjacent disc degeneration was the most common mechanism causing PJK. Fracture dislocation presented earliest and with the most kyphosis. Reoperation occurred most often with screw pullout, fracture dislocation, and UIV+1 fracture. The overall rate of neurologic deficit was low and occurred most often with screw haloing and UIV+1 fracture.

BACKGROUND AND OBJECTIVES:When performing a 3-column osteotomy (3CO) in adult spinal deformity surgery, osteotomy closure carries major risk. The construct-to-construct closure technique has been previously described as a safe means to close a 3CO. We sought to provide an in-depth description of the construct-to-construct closure technique through a case series using illustrations and intraoperative pictures and videos for spine surgeons looking to incorporate this technique. METHODS:A retrospective, single-surgeon case series was undertaken of 3COs using the construct-to-construct closure technique. A detailed description of the technique with corresponding illustrations was provided. For each case, a summary with key intraoperative pictures and videos was included. Descriptive statistics were performed. RESULTS:Seven patients (mean age: 57.1 ± 10.2 years; 57% females) underwent a 3CO with mean follow-up of 12 months at the following levels: L4, T11, L3, T10, T10-12, T12, and L2. Construct-to-construct closure was used in all cases with a mean correction of 36.3° ± 5.8° (range 28°-47°). Neuromonitoring data were stable in 5 cases, but a significant decrease in data was seen during osteotomy closure in 2 cases. In the 2 cases where data were lost, the correction was quickly released in a controlled manner and the postoperative neurological examination was stable to improved. No cases of screw pullout, screw plowing, or subluxation occurred. CONCLUSION:The current case series provides an in-depth description of the construct-to-construct closure technique to close a 3CO and is accompanied by illustrations and intraoperative pictures and videos.

OBJECTIVE:Patients presenting emergently with neoplastic spinal cord compression without known histology pose a complex decision for spine surgeons. In this patient population, the authors sought to 1) describe presentation/histology, 2) determine if emergency surgery was indicated, and 3) compare survival to that of patients with known histology prior to surgery. METHODS:A retrospective, cohort study of patients who underwent extradural spine tumor surgery between 2010 and 2021 was undertaken. The inclusion criteria were neoplastic spinal cord compression and emergency department or emergency clinical presentation without known tumor histology or cancer history. Histology was classified as radiosensitive (lymphoma, leukemia, small cell lung cancer, germ cell cancer), radio-intermediate (breast, prostate), and radioresistant (all others). Stability was determined with the Spine Instability Neoplastic Score (SINS). Descriptive/bivariate and multivariable Cox regression statistics were performed. RESULTS:Of 371 patients who underwent surgery for extradural spine tumors, 80 (21.6%) had emergency presentation without a known histological diagnosis. The mean ± SD age was 60.5 ± 12.4 years, 65% of patients were male, and the mean follow-up was 530.5 ± 738.0 days. Although spinal cord compression was seen in all (100%) patients, a neurological deficit was seen in only 43 (53.7%). Final pathology revealed that 59 (73.7%) patients had radioresistant tumors, 12 (15.0%) radio-intermediate, and 9 (11.3%) radiosensitive; of note, 2/80 (2.5%) had primary bone tumors. Accepting that those patients with radioresistant pathology would need separation surgery regardless, 11 of the 21 (52.4%) patients with radio-intermediate or radiosensitive pathology had a neurological deficit, and thus surgery was indicated. In the remaining 10 patients without a neurological deficit, SINS was stable/indeterminate in 8 patients (10% of patients with unknown diagnosis), for whom surgery may have been avoided. Multivariable Cox regression showed that patients without known histology at the time of surgery had decreased overall survival compared to those with known histology preoperatively (HR 1.64, 95% CI 1.17-2.30, p = 0.004). CONCLUSIONS:Among 80 patients with emergency presentation of neoplastic spinal cord compression without known histology, 90% ultimately had histology, neurological status, or instability favorable for surgery, thus affirming the surgeons' choice to operate. However, 1 in 10 patients could have potentially been treated with radiation and/or systemic treatment alone. Two patients (3%) had primary bone tumors, foregoing the chance of a negative margin resection. Not knowing histology preoperatively was independently associated with decreased overall survival. These results provide empirical data for a challenging yet not uncommon situation for spine surgeons and reinforce the importance of knowing histology prior to spine tumor surgery when safe and feasible.

BACKGROUND CONTEXT In adult spinal deformity (ASD) surgery, the lumbosacral fractional curve (LSF) is often stiffer and harder to correct than the more flexible major thoracic/lumbar curve (MC). PURPOSE In patients undergoing ASD surgery, we aimed to: 1) assess correction rate of the LSF vs. MC, 2) determine association between correction of each curve and postoperative coronal malalignment (CM), sagittal malalignment, and mechanical complications. STUDY DESIGN/SETTING Retrospective cohort study. PATIENT SAMPLE A retrospective cohort study was performed of patients undergoing ASD surgery from 2009-23 with 2-year follow-up. OUTCOME MEASURES The primary outcome was postoperative CM (coronal vertical axis, CVA >3cm), and mechanical complications. Secondary outcomes were sagittal malalignment (sagittal vertical axis, SVA>5cm) and/or L1-pelvic angle±3° (L1PA). METHODS A retrospective cohort study was performed of patients undergoing ASD surgery from 2009-23 with 2-year follow-up. LSF and largest of the main thoracic or thoracolumbar/lumbar curves were evaluated. The primary outcome was postoperative CM (coronal vertical axis, CVA >3cm), and mechanical complications. Secondary outcomes were sagittal malalignment (sagittal vertical axis, SVA>5cm) and/or L1-pelvic angle±3° (L1PA). Bivariate and multivariable logistic regression were performed controlling for age, sex, body mass index, and preoperative SVA. RESULTS Of the 174 patients undergoing ASD surgery, the mean age was 60±19 years and 127 (73%) were females. Mean preoperative LSF and MC were 13±10° and 32±18°, respectively, and mean preoperative/postoperative CVA were 26±25 mm and 20±21 mm respectively. Postoperative CM was seen in 35 (20%) patients. Improvement in LSF and MC was seen in 55% vs 76% (p<0.001). The cohort was then divided into 4 groups based on each curve correction. No significant difference was seen in postoperative CM (p=0.060) or CVA (p=0.216) between the four groups. However, comparing patients with only the LSF curve vs only the MC corrected, LSF curve correction only increased the risk of postoperative CM (33% vs 10%, p=0.038, OR=0.2, 95%CI: 0.0-1.0, p=0.048). Patients with only LSF corrected had the highest postoperative SVA (p=0.010), but this was lost on multivariable regression (β=0.2, 95%CI:-4.9-5.3, p=0.940). Mechanical complications (p=0.954) and reoperations (p=0.957) were similar between the groups. CONCLUSIONS The LSF was corrected less frequently than the MC. Coronal malalignment was more commonly seen when only the LSF curve was corrected compared to only the MC corrected. No significant differences were noted in postoperative alignment or mechanical complications across the groups. These findings emphasize the importance of reconciling correction of both the LSF curve and MC to maintain optimal coronal/sagittal alignment. FDA Device/Drug Status This abstract does not discuss or include any applicable devices or drugs.

Background:Management of multiple myeloma (MM) of the spine includes a multimodal approach consisting of chemotherapy, bisphosphonates, radiation, and surgical intervention. This study aims to explore the trends in surgical treatment of MM including hospital costs, odds of complications, and the impact of patient comorbidities on the risk of complications using the National Inpatient Sample (NIS) database. Methods:The NIS was queried for patients with MM and plasmacytoma of the spine who underwent surgical intervention between 2005 and 2014. Rates of spinal decompression, spinal stabilization with or without decompression, and vertebral augmentation were analyzed. The effect of various patient characteristics on outcome was analyzed by multivariate analysis and stratified by surgical procedure. Results:Vertebral augmentation (9,643, 65.7%) was the most commonly performed procedure, followed by spinal stabilization with or without decompression (4,176, 28.4%) and then decompression alone (868, 5.9%). The total population-adjusted rate of surgical management for MM remained stable during the study period, while the rate of spinal stabilization increased (P<0.001) and the rate of vertebral augmentation decreased (P=0.01). Vertebral augmentation was associated with shorter inpatient hospital stay, lower total cost, and higher likelihood of discharging to home. The complication rate increased over time for vertebral augmentation procedures (P<0.001) while spinal stabilization and decompression complication rates remained stable. The complication rate for all procedures was higher in male patients (P<0.001) and increased with the number of patient comorbidities (P<0.001). Conclusions:Spinal surgery seems to be increasing for the management of spinal MM in the inpatient setting, while the rate of vertebral augmentation is decreasing. Vertebroplasty and similar palliative procedures may continue to decrease as advancements in surgical technology and technique allow for safer surgical intervention. The decision to employ aggressive surgical intervention, however, must always take into account the patient's comorbidities, overall systemic disease burden, and the potential for significant enhancement in meaningful clinical outcome.

Background We sought to determine which aspect of the upper instrumented vertebrae (UIV)-tilt angle or screw angle-was more strongly associated with: (1) proximal junctional kyphosis/failure (PJK/F), (2) other mechanical complications and reoperations, and (3) patient-reported outcome measures (PROMs). Methods A single-institution, retrospective cohort study was undertaken for patients undergoing adult spinal deformity (ASD) surgery from 2011 to 2017. Only patients with UIV at T7 or below were included. The primary exposure variables were UIV tilt angle (the angle of the UIV inferior endplate and the horizontal) and UIV screw angle (the angle of the UIV screws and superior endplate). Multivariable logistic regression included age, body mass index, osteopenia/osteoporosis, postoperative sagittal vertical axis, postoperative pelvic-incidence lumbar lordosis mismatch, UIV tilt angle, and UIV screw angle. Results One hundred and seventeen patients underwent adult spinal deformity surgery with a minimum of 2-year follow-up. A total of 41 patients (35.0%) had PJK and 26 (22.2%) had PJF. (1) UIV tilt angle: 96 (82.1%) had lordotic UIV tilt angles, 6 (5.1%) were neutral, and 15 (12.8%) were kyphotic. (2) UIV screw angle: 38 (32.5%) had cranially directed screws, 4 (3.4%) were neutral, and 75 (64.1%) were caudally directed. Both lordotic-angled UIV endplate (OR = 1.06, 95% CI = 1.01-1.12, and P = 0.020) and cranially directed screws (OR = 1.19, 95% CI = 1.07-1.33, and P < 0.001) were associated with higher odds of PJK, with a more pronounced effect of UIV screw angle compared with UIV tilt angle (Wald test, 9.40 vs 4.42). Similar results were found for PJF. Neither parameter was associated with other mechanical complications, reoperations, or patient-reported outcome measures. Conclusions UIV screw angle was more strongly associated with development of PJK/F compared with tilt angle. Overall, these modifiable parameters are directly under the surgeon's control and can mitigate the development of PJK/F.

Cerebral arteriovenous malformations (AVMs) are a leading cause of intracerebral hemorrhage in both children and young adults. With the continued advancement of science and technology, the understanding of the pathophysiology behind the development of these lesions has evolved. From early theory published by Harvey Cushing and Percival Bailey in 1928, Tumors Arising from the Blood-vessels of the Brain: Angiomatous Malformations and Hemangioblastoma, which regarded AVMs as tumors arising from blood vessels, to the meticulous artistry of Dorcas Padget’s embryological cataloguing of the cerebral vasculature in 1948, to the proliferative capillaropathy theory of Yaşargil in 1987, to Ramey’s 2014 hierarchical model of vascular development, there have been multiple hypotheses of congenital, developmental, and genetic two-hit theories in the pathogenesis of AVMs. Most recent evidence implicates somatic KRAS mutations in the cerebral endothelium, producing an important understanding of the pathogenesis of this disease, which is critical to the development of targeted therapeutics. The authors present the historical progression of their understanding of AVM pathogenesis. They focus on the foundation laid by early pioneers, discussing embryological anatomy and vasculogenesis, the prominent theories of AVM development that have emerged over time, and culminate in an overview of the most current understanding of the pathogenesis of these complex vascular lesions and the clinical implications of our scientific progress.

BACKGROUND AND OBJECTIVES:Open thoracic diskectomy often requires significant bone resection and fusion, whereas an endoscopic thoracic diskectomy offers a less invasive alternative. Therefore, we sought to compare one-level open vs endoscopic thoracic diskectomy regarding (1) perioperative outcomes, (2) neurological recovery, and (3) total cost. METHODS:A single-center, retrospective, cohort study using prospectively collected data of patients undergoing one-level thoracic diskectomy was undertaken from 2018 to 2023. The primary exposure variable was open vs endoscopic. The primary outcome was perioperative outcomes and neurological recovery. Secondary outcomes were total cost of care. Multivariable regression analysis controlled for age, body mass index, sex, symptom onset, disk characteristics, operative time, and length of stay. RESULTS:Of 29 patients undergoing thoracic diskectomy, 17 were open and 12 were endoscopic. Preoperative demographics, symptoms, and radiographic findings were comparable between the cohorts. Perioperatively , open surgery had significantly higher mean length of stay (4.9 ± 1.5 vs 0.0 ± 0.0 days, P < .001), median (IQR) longer operative time (342.8 [68.4] vs 141.5 [36] minutes, P < .001), and more blood loss (350 [390] vs 6.5 [20] mL; P < .001). 16 (94%) open patients required fusion vs 0 endoscopic ( P < .001). Postoperative opioid use ( P = .119), readmission ( P = .665), reoperation ( P = .553), and rate of neurological improvement ( P > .999) were similar between the 2 groups. Financially, open surgical median costs were 7x higher than endoscopic ($59 792 [$16 118] vs $8128 [$1848]; P < .001), driven by length of stay (β = $2261/night, P < .001), open surgery (β = $24 106, P < .001), and number of pedicle screws (β = $1829/screw, P = .002) on multivariable analysis. On sensitivity analysis, open surgery was never cost-efficient against endoscopic surgery and excess endoscopic revision rates of 86% above open revision rates were required for break-even costs between the surgical approaches. CONCLUSION:Endoscopic thoracic diskectomy was associated with decreased length of stay, operative time, blood loss, and total cost compared with the open approach, with similar neurological outcomes. These findings may help patients and surgeons seek endoscopic approach as a less morbid and less costly alternative.

STUDY DESIGN:Retrospective cohort study. OBJECTIVES:In patients undergoing elective anterior cervical discectomy and fusion (ACDF), we sought to determine the impact of screw length on: (1) radiographic pseudarthrosis, (2) pseudarthrosis requiring reoperation, and (3) patient-reported outcome measures (PROMs). METHODS:A single-institution, retrospective cohort study was undertaken from 2010-21. The primary independent variables were: screw length (mm), screw length divided by the anterior-posterior vertebral body diameter (VB%), and the presence of any screw with VB% < 75% vs all screws with VB% ≥ 75%. Multivariable logistic regression controlled for age, BMI, gender, smoking, American Society of Anesthesiology grade, number of levels fused, and whether a corpectomy was performed. RESULTS:Of 406 patients undergoing ACDF, levels fused were: 1-level (39.4%), 2-level (42.9%), 3-level (16.7%), and 4-level (1.0%). Mean screw length was 14.3 ± 2.3 mm, and mean VB% was 74.4 ± 11.2. A total of 293 (72.1%) had at least one screw with VB% < 75%, 113 (27.8%) had all screws with VB% ≥ 75%, and 141 (34.7%) patients had radiographic pseudarthrosis at 1-year. Patients who had any screw with VB% < 75% had a higher rate of radiographic pseudarthrosis compared to those had all screws with VB% ≥ 75% (39.6% vs 22.1%, P < .001). Multivariable logistic regression revealed that a higher VB% (OR = .97, 95%CI = .95-.99, P = .035) and having all screws with VB% ≥ 75% (OR = .51, 95%CI = .27-.95, P = .037) significantly decreased the odds of pseudarthrosis at 1-year, with no difference in reoperation or PROMs (all P > .05). CONCLUSION:Longer screws taking up ≥75% of the vertebral body protected against radiographic pseudarthrosis at 1-year. Maximizing screw length in ACDF is an easily modifiable factor directly under the surgeon's control that may mitigate the risk of pseudarthrosis.

Optimal management of metastatic lung cancer to the spine (MLCS) incorporates a multidisciplinary approach. With improvements in lung cancer screening and nonsurgical treatment, the role for surgery may be affected. The objective of this study is to assess trends in the surgical management of MLCS using the National Inpatient Sample (NIS) database. The NIS was queried for patients with MLCS who underwent surgery from 2005 to 2014. The frequencies of spinal decompression alone, spinal stabilization with or without (+/-) decompression, and vertebral augmentation were calculated. Statistical analysis was performed to analyze the effect of patient characteristics on outcomes. The most common procedure performed was vertebral augmentation (10719, 44.3%), followed by spinal stabilization +/decompression (8634, 35.7%) and then decompression alone (4824, 20.0%). The total number of surgeries remained stable, while the rate of spinal stabilizations increased throughout the study period (p < 0.001). Invasive procedures such as stabilization and decompression were associated with greater costs, length of stay, complications and mortality. Increasing comorbidity was associated with increased odds of complication, especially in patients undergoing more invasive procedures. In patients with low pre-operative comorbidity, the type of procedure did not influence the odds of complication. Graded increases in length of stay, cost and mortality were seen with increasing complication rate. The rate of spinal stabilizations increased, which may be due to either increased early detection of disease facilitating use of outpatient vertebral augmentation procedures and/or the recognition that surgical decompression and stabilization are necessary for optimal outcome in the setting of MLCS with neurological deficit. (c) 2021 Elsevier Ltd. All rights reserved.

Background: A primary etiology of adolescent idiopathic scoliosis (AIS) is currently unknown, but poor postural control of the spinal extensor musculature has been identified as an AIS risk factor. Identifiable postural differences would aid in advancing the precise postural behaviors that should be modified during Physiotherapy Scoliosis Specific Exercise (PSSE) to help limit the progression of AIS. Research question: Are there any determinable differences in lumbopelvic posture or range of motion between subjects with AIS and controls? Methods: This prospective cohort pilot study consisted of 53 subjects (27 AIS and 26 control) aged 11-17 years. Subjects had their lumbopelvic posture assessed and monitored using the ViMove DorsaVi sensor package. All subjects underwent a live assessment to obtain initial lumbopelvic (LP) range of motion (ROM) measurements. Subjects were then monitored while continuing with normal activities of daily living (ADLs) for 12 h. With an alpha level of 0.05, nonparametric analyses were performed for each variable via a Mann-Whitney U-test. Results: During the live assessment, controls exhibited a significantly greater anterior pelvic tilt ROM in the sitting position than the AIS group (p = 0.0433). When compared to female controls, females with AIS had a sitting pelvic tilt ROM that was significantly more retroverted (p = 0.0232) and less anteverted (p = 0.0010). During ADLs, female controls exhibited a higher total number of extension events than their female with AIS (p = 0.0263). These associations did not strengthen with greater spinal deformity. Significance: This work demonstrates postural differences between patients with AIS and controls. Further study is necessary to determine why patients with AIS adopt these postures, and if PSSEs can be utilized to limit the progression of AIS.