Endovascular treatment of pediatric basilar artery aneurysms: case series and literature review.

PURPOSE: Pediatric basilar artery aneurysms are rare and challenging to treat. Microsurgical options and standard endovascular coiling are often undesirable choices for treatment of this pathology. Additional endovascular strategies are needed. METHODS: Presentation, diagnosis, and management of pediatric basilar aneurysms were reviewed, with an emphasis on endovascular treatment strategies. Our case series of 2 patients was presented in detail, one treated with flow diversion and vessel sacrifice and one treated with stent-assisted coiling. An extensive review of the literation was performed to find other examples of pediatric basilar artery aneurysms treated with endovascular techniques. RESULTS: Twenty-nine studies met inclusion criteria. Fifty-nine aneurysms in 58 patients were treated using endovascular techniques. Mortality rate was 10.3% (6/58) and a poor outcome (GOS 1-3) occurred in 15.5% (9/58). There were 4 reported recurrences requiring retreatment; however, only 46.5% of patients had reported follow-up of at least 1 year. 71.1% (42/59) were dissecting aneurysms. CONCLUSION: Basilar artery aneurysms in the pediatric population are rare, commonly giant and fusiform, and often not amenable to microsurgical or coiling techniques. The surrounding vasculature, location, size, and morphology of the aneurysm along with the durability of treatment must be considered in treatment decisions. With proper patient selection, stent-assisted coiling and flow diversion may increase the durability and safety of endovascular treatment in this population.

The charlotte large artery occlusion endovascular therapy outcome score compares favorably to the critical area perfusion score for prognostication before basilar thrombectomy.

INTRODUCTION: The Critical Area Perfusion Score (CAPS) predicts functional outcomes in vertebrobasilar thrombectomy patients based on computed tomography perfusion (CTP) hypoperfusion. We compared CAPS to the clinical-radiographic Charlotte Large artery occlusion Endovascular therapy Outcome Score (CLEOS). METHODS: Acute basilar thrombosis patients from January 2017-December 2021 were included in this retrospective analysis from a health system's stroke registry. Inter-rater reliability was assessed for 6 CAPS raters. A logistic regression with CAPS and CLEOS as predictors was performed to predict 90-day modified Rankin Scale (mRS) score 4-6. Area under the curve (AUC) analyses were performed to evaluate prognostic ability. RESULTS: 55 patients, mean age 65.8 (± 13.1) years and median NIHSS score 15.55-24, were included. Light's kappa among 6 raters for favorable versus unfavorable CAPS was 0.633 (95% CI 0.497-0.785). Increased CLEOS was associated with elevated odds of a poor outcome (odds ratio (OR) 1.0010, 95% CI 1.0007-1.0014, p<0.01), though CAPS was not (OR 1.0028, 95% CI 0.9420-1.0676, p=0.93). An overall favorable trend was observed for CLEOS (AUC 0.69, 95% CI 0.54-0.84) versus CAPS (AUC 0.49, 95% CI 0.34-0.64; p=0.051). Among 85.5% of patients with endovascular reperfusion, CLEOS had a statistically higher sensitivity than CAPS at identifying poor 90-day outcomes (71% versus 21%, p=0.003). CONCLUSIONS: CLEOS demonstrated better predictive ability than CAPS for poor outcomes overall and in patients achieving reperfusion after basilar thrombectomy.

Endovascular Thrombectomy Reduces Risk of Poor Functional Outcomes in Patients Presenting within 0-6 Hours with Large Ischemic Core Volumes on Computed Tomography Perfusion.

INTRODUCTION: Patients presenting with large ischemic core volumes (LICVs) on computed tomography perfusion (CTP) are at high risk for poor functional outcomes. We sought to identify predictors of outcome in patients with an internal carotid artery (ICA) or middle cerebral artery (MCA) occlusion and LICV. METHODS: A large healthcare system's prospectively collected code stroke registry was utilized for this retrospective analysis of patients presenting within 6 hours with at least 50 ml of CTP reduced relative cerebral blood flow (CBF) < 30%. A multivariable logistic regression model was constructed to identify independent predictors (p < 0.05) of poor discharge outcome (modified Rankin scale score 4-6). RESULTS: Over a 38-month period, we identified 104 patients meeting inclusion criteria, with a mean age of 65.4 ± 16.2 years, median presenting National Institutes of Health Stroke Scale score 20 (IQR 16-24), median ischemic core volume (CBF < 30%) 82 ml (IQR 61-118), and median mismatch volume 80 ml (IQR 56-134). Seventy-five patients (72.1%) had a discharge modified Rankin scale score of 4-6. Sixty-six of 104 (63.5%) patients were treated with endovascular thrombectomy (EVT). In the multivariable regression model, EVT (OR 0.303; 95% CI 0.080-0.985; p = 0.049) and lower blood glucose (per 1-point increase, OR 1.014; 95% CI 1.003-1.030; p = 0.030) were independently protective against poor discharge outcome. CONCLUSIONS: EVT is independently associated with a reduced risk of poor functional outcome in patients presenting within 6 hours with ICA or MCA occlusions and LICV.

Redefining Mild Traumatic Brain Injury (mTBI) delineates cost effective triage.

OBJECTIVES: Mild traumatic brain injury (mTBI) is defined as Glasgow Coma Score (GCS) of 14 or 15. Despite good outcomes, patients are commonly transferred to trauma centers for observation and/or neurosurgical consultation. The aim of this study is to assess the value of redefining mTBI with novel radiographic criteria to determine the appropriateness of interhospital transfer for neurosurgical evaluation. METHODS: A retrospective study of patients with blunt head injury with GCS 13-15 and CT head from Jan 2014-Dec 2016 was performed. A novel criteria of head CT findings was created at our institution to classify mTBI. Outcomes included neurosurgical intervention and transfer cost. RESULTS: A total of 2120 patients were identified with 1442 (68.0%) meeting CT criteria for mTBI and 678 (32.0%) classified high risk. Two (0.14%) patients with mTBI required neurosurgical intervention compared with 143 (21.28%) high risk TBI (p < 0.0001). Mean age (55.8 years), and anticoagulation (2.6% vs 2.8%) or antiplatelet use (2.1% vs 3.0%) was similar between groups (p > 0.05). Of patients with mTBI, 689 were transferred without receiving neurosurgical intervention. Given an average EMS transfer cost of $700 for ground and $5800 for air, we estimate an unnecessary transfer cost of $733,600. CONCLUSION: Defining mTBI with the described novel criteria clearly identifies patients who can be safely managed without transfer for neurosurgical consultation. These unnecessary transfers represent a substantial financial and resource burden to the trauma system and inconvenience to patients.

Posterior Transdural Repair of a Spontaneous Ventral Thoracic Cerebrospinal Fluid Leak: 2-Dimensional Operative Video.

Spontaneous intracranial hypotension is a rare but serious condition characterized by orthostatic headaches and a variety of neurological symptoms. 1,2 Spontaneous intracranial hypotension should be considered in all patients with new onset, daily, persistent headaches, and orthostatic symptoms. It is typically caused by spontaneous spinal cerebrospinal fluid (CSF) leaks. 1,2 Traditional first-line treatments include hydration, bedrest, epidural blood patches, and fibrin glue injections. However, refractory cases often require surgical intervention, especially those caused by a small ventral osteophyte, which is classified as a type 1 leak. 3-5 The small osteophyte causes a tear in the dura of the ventral canal, usually near the cervicothoracic junction. Diagnosis of these leaks is challenging because these small osteophytes can also occur asymptomatically, or patients may have several of them at multiple levels. Typically, dynamic myelography is needed for accurate localization due to the inadequacy of standard imaging. 6 This video details a young patient with refractory spontaneous intracranial hypotension from a type 1 spontaneous CSF leak, treated successfully using a posterior transdural surgical approach with spinal cord mobilization. Our video presentation outlines the surgical technique and provides an overview of this underdiagnosed condition. Our described approach offers direct visualization, suturing of the leak site, and a multilayer repair without the need for spinal fusion. It also avoids the morbidity to the neck, chest, and mediastinal structures that is at risk with lateral or anterior approaches. A combined intradural and extradural repair may enhance the durability of repair for ventral CSF leaks. The patient consented to the procedure. This operative video did not require Institutional Review Board approval as all patient information has been anonymized, ensuring no identifiable information is disclosed. The video is a single case that does not involve interventions or pose risks beyond standard care, adhering to ethical guidelines and institutional policies.

Neurological outcomes for patients meeting radiographic criteria for DEFUSE 3 and SELECT2.

BACKGROUND: The DEFUSE 3 and SELECT2 thrombectomy trials included some patients with similar radiographic profiles, although the rates of good functional outcomes differed widely between the studies. OBJECTIVE: To report neurological outcomes for patients who meet CT and CT perfusion (CTP) inclusion criteria common to both DEFUSE 3 and SELECT2. METHODS: Retrospective study of thrombectomy patients, presenting between November 2016 and December 2023 to a large health system, with Alberta Stroke Program Early CT score ≥6, core infarction 50-69 mL, mismatch ratio ≥1.8, and mismatch volume ≥15 mL. The primary outcome was 90-day modified Rankin Scale score 0-2. A logistic regression analysis was performed to identify independent predictors of the primary outcome. RESULTS: 85 patients, with mean age 64.6 (16.6) years and median National Institutes of Health Stroke Scale score 18 (15-23), were included. Thirty-eight of 85 patients (44.7%) were functionally independent at 90 days. Predictors of functional independence included age (OR=0.943, 95% CI 0.908 to 0.980; P=0.003), initial glucose (OR=0.989, 95% CI 0.978 to 1.000; P=0.044), and time last known well to skin puncture (OR=0.997, 95% CI 0.994 to 1.000; P=0.028). The area under the curve for the multivariable model predicting the primary outcome was 0.82 (95% CI 0.73 to 0.92). CONCLUSION: Nearly half of patients meeting radiographic criteria common to DEFUSE 3 and SELECT2 are functionally independent at 90 days, similar to rates reported for the treated DEFUSE 3 cohort. This might be due to their moderate core volumes and large ischemic penumbra.

Is Thoracic Paddle Lead Spinal Cord Stimulator Implantation Safe in an Ambulatory Surgery Center?

OBJECTIVE: Spinal cord stimulation is an effective treatment modality for chronic pain. Although percutaneous leads are commonly placed in the outpatient setting, paddle leads are typically implanted in the inpatient setting. Given the substantial cost savings associated with the ambulatory setting, we aimed to demonstrate the feasibility and safety of thoracic paddle lead implantation in a freestanding ambulatory surgery center (ASC). METHODS: Consecutive patients undergoing thoracic paddle lead implantation at a single freestanding ASC from January 2015 to December 2020 were queried. Demographic, perioperative, and outcome data were collected. Primary outcomes were incidence of intraoperative or immediate postoperative complications and need for inpatient transfer. Secondary outcomes included readmission at 30 and 90 days and reoperation at 30 days, 90 days, and 1 year. RESULTS: A total of 46 patients underwent ambulatory thoracic paddle lead implantation over the study period. Two patients (4.3%) suffered an immediate postoperative complication requiring return to surgery at the ASC-one for an epidural hematoma, and one for a flank hematoma. All but one patient (97.8%) were discharged home on the day of surgery. The overall 30- and 90-day readmission rates were 4.3% and 6.5%, respectively. One patient (2.2%) required reoperation for a mechanical complication. No device-related infections were noted during the follow-up period. CONCLUSIONS: Thoracic laminotomy for paddle lead spinal cord stimulator implantation can be performed in a freestanding ASC with complication rates comparable to the hospital setting. Future comparative studies that assess clinical outcomes and cost are necessary to determine the cost-effectiveness of the ambulatory setting.

Surgical treatment for chronic subdural hematoma in the elderly: A retrospective analysis.

Background: Chronic subdural hematoma (CSDH) is primarily a disease of the elderly. Less invasive interventions are often offered for elderly (> 80 years) patients due to concerns for elevated surgical risk, although data suggesting a clear outcome benefit is lacking. Methods: All patients aged 65 years or older who underwent surgical treatment for CSDH at a single institution over a 4-year period were evaluated in this retrospective analysis. Surgical options included twist drill craniostomy (TDC), burr hole craniotomy (BHC), or standard craniotomy (SC). Outcomes, demographics, and clinical data were collected. Practice patterns and outcomes for patients older than 80 years old were compared to the age 65-80 cohort. Results: 110 patients received TDC, 35 received BHC, and 54 received SC. There was no significant difference in post-operative complications, outcomes, or late recurrence (30-90 days). Recurrence at 30 days was significantly higher for TDC (37.3% vs. 2.9% vs 16.7%, p 80 group, SC had higher risk of stroke and increased length of stay. Conclusion: Twist drill craniostomy, burr hole craniostomy, and standard craniotomy have similar neurologic outcomes in elderly patients. Presence of thick membranes is a relative contra-indication for TDC due to high 30-day recurrence. Patients > 80 have higher risk of stroke and increased length of stay with SC.

The Charlotte Large Artery Occlusion Endovascular Therapy Outcome Score Predicts Poor Outcomes 1 Year After Endovascular Thrombectomy.

OBJECTIVE: We evaluated the ability of several outcome prognostic scales to predict poor 1-year outcomes and mortality after endovascular thrombectomy. METHODS: In this retrospective analysis from the stroke registry of a large integrated health system, consecutive patients presenting from August 2020 to September 2021 with an anterior circulation large-vessel occlusion stroke treated with endovascular thrombectomy were included. Multivariable logistic regression was performed to determine the ability of each scale to predict the primary outcome (1-year modified Rankin Scale [mRS] score of 4-6) and the secondary outcome (1-year mortality). Area under the curve analyses were performed for each scale. RESULTS: In 237 included patients (mean age 68 [±15] years; median National Institutes of Health Stroke Scale score 16 [11-21]), poor 1-year outcomes were present in 116 patients (49%) and 1-year mortality was 34%. The CLEOS (Charlotte Large Artery Occlusion Endovascular Therapy Outcome Score), which incorporates age, baseline National Institutes of Health Stroke Scale score, initial glucose level, and computed tomography perfusion cerebral blood volume index, had a significant association with poor 1-year outcomes (per 25-point increase; odds ratio, 1.0134; P = 0.02). CLEOS and PRE (Pittsburgh Response to Endovascular Therapy) were both significantly associated with 1-year mortality. Area under the curve values were comparable for CLEOS, PRE, Houston Intra-Arterial Therapy 2, and Totaled Health Risks in Vascular Events to predict 1-year mRS score 4-6 and mortality. Only 1 of 18 patients with CLEOS ≥690 had a 1-year mRS score of 0-3. CONCLUSIONS: CLEOS can predict poor 1-year outcomes and mortality for patients with anterior circulation large-vessel occlusion using prethrombectomy variables.

Predicting severe disability or death in endovascular thrombectomy with large computed tomography perfusion core infarction and limited penumbra.

BACKGROUND: Patients presenting with large core infarctions benefit from treatment with endovascular thrombectomy (EVT), with a notable 50% reduction in rates of severe disability (modified Rankin Scale [mRS] 5) at 90 days. We studied the ability of previously reported prognostic scales to predict devastating outcomes in patients with a large ischemic core and limited salvageable brain tissue. METHODS: Retrospective analysis from a health system's code stroke registry, including consecutive thrombectomy patients from November 2017 to December 2022 with an anterior circulation large vessel occlusion, computed tomography perfusion core infarct ≥ 50 ml, and mismatch volume < 15 ml or mismatch ratio < 1.8. Previously reported scales were compared using logistic regression and area under the curve (AUC) analyses to predict 90-day mRS 5-6. RESULTS: Sixty patients (mean age 62.38 ± 14.25 years, median core volume 103 ml [74.75-153]) met inclusion criteria, of whom 27 (45%) had 90-day mRS 5-6. The Charlotte Large artery occlusion endovascular therapy Outcome Score (CLEOS) (odds ratio [OR] 1.35, 95% CI [1.14-1.60], p = 0.0005), Houston Intra-Arterial Therapy-2 (OR 1.35, 95% CI [1.00-1.83], p = 0.0470), and Totaled Health Risks in Vascular Events (OR 1.53, 95% CI [1.07-2.18], p = 0.0199) predicted the primary outcome in the logistic regression analysis. CLEOS performed best in the AUC analysis (AUC 0.83, 95% CI [0.72-0.94]). CONCLUSION: CLEOS predicts devastating outcomes after EVT in patients with large core infarctions and small volumes of ischemic penumbra.

The Charlotte Large artery occlusion Endovascular therapy Outcome Score predicts independent outcome after thrombectomy.

BACKGROUND AND PURPOSE: Predicting functional outcomes after endovascular thrombectomy (EVT) is of interest to patients and families as they navigate hospital and post-acute care decision-making. We evaluated the prognostic ability of several scales to predict good neurological function after EVT. METHODS: We retrospectively analyzed records from a health system's code stroke registry, including consecutive successful thrombectomy patients from August 2020 to February 2023 presenting with an anterior circulation large vessel occlusion who were evaluated with pre-EVT CT perfusion. Primary and secondary outcomes were 90-day modified Rankin Scale (mRS) scores 0-2 and 0-1, respectively. Logistic regression was performed to evaluate the ability of each scale to predict the outcomes. Scales were compared by calculating the area under the curve (AUC). RESULTS: A total of 465 patients (mean age 68.1 [±14.9] years, median National Institutes of Health Stroke Scale [NIHSS] 16 [11-21]) met inclusion criteria. In the logistic regression, the Charlotte Large artery occlusion Endovascular therapy Outcome Score (CLEOS), Totaled Health Risks in Vascular Events, Houston Intra-Arterial Therapy-2, Pittsburgh Response to Endovascular therapy, and Stroke Prognostication using Age and NIHSS were significant in predicting the primary and secondary outcomes. CLEOS was superior to all other scales in predicting 90-day mRS 0-2 (AUC .75, 95% confidence interval [CI] .70-.80) and mRS 0-1 (AUC .74, 95% CI .69-.78). Twenty of 22 patients (90.9%) with CLEOS <315 had 90-day mRS 0-2. CONCLUSIONS: CLEOS predicts independent and excellent neurological function after anterior circulation EVT.

Predictors of devastating functional outcome despite successful basilar thrombectomy.

BACKGROUND: Basilar thrombosis frequently leads to poor functional outcomes, even with good endovascular reperfusion. We studied factors associated with severe disability or death in basilar thrombectomy patients achieving revascularization. METHODS: We retrospectively analyzed records from a health system's code stroke registry, including successful basilar thrombectomy patients from January 2017 to May 2023 who were evaluated with pretreatment computed tomography perfusion. The primary outcome was devastating functional outcome (90-day modified Rankin Scale [mRS] score 5-6). A multivariable logistic regression model was constructed to determine independent predictors of the primary outcome. The area under the receiver operator characteristics curve (AUC) was calculated for the model distinguishing good from devastating outcome. RESULTS: Among 64 included subjects, with mean (standard deviation) age 65.6 (14.1) years and median (interquartile range) National Institutes of Health Stroke Scale (NIHSS) 18 (5.75-24.5), the primary outcome occurred in 28 of 64 (43.8%) subjects. Presenting NIHSS (odds ratio [OR] 1.08, 95% confidence interval [CI] 1.01-1.14, p = 0.02), initial glucose (OR 0.99, 95% CI 0.97-1.00, p < 0.05), and proximal occlusion site (OR 7.38, 95% CI 1.84-29.60, p < 0.01) were independently associated with 90-day mRS 5-6. The AUC for the multivariable model distinguishing outcomes was 0.81 (95% CI 0.70-0.92). CONCLUSION: We have identified presenting stroke severity, lower glucose, and proximal basilar occlusion as predictors of devastating neurological outcome in successful basilar thrombectomy patients. These factors may be used in medical decision making or for patient selection in future clinical trials.

Visualization of the Anterior Temporal Artery as a Predictor of Outcome in Middle Cerebral Artery Occlusion Patients Achieving Successful Recanalization After Transfer.

Introduction Anterior temporal artery (ATA) visualization on computed tomography angiography (CTA) has been previously associated with good outcomes in middle cerebral artery (MCA) occlusions, but not in the setting of patients who initially present to non-thrombectomy centers. Methods We retrospectively identified acute MCA (M1) occlusion patients who underwent mechanical thrombectomy after transfer from non-thrombectomy-capable centers. Neuroradiologists confirmed the MCA (M1) as the most proximal site of occlusion on CTA and assessed for visualization of the ATA. Thrombolysis in Cerebral Infarction (TICI) 2b or greater revascularization scores were confirmed by neurointerventionalists blinded to patient outcomes. Ninety-day modified Rankin scale (mRS) scores were obtained via a structured telephone questionnaire. Results We identified 102 M1 occlusion patients over a three-and-a-half-year period presenting to a non-thrombectomy-capable center who underwent transfer and mechanical thrombectomy. There were no significant differences in age, gender, race, comorbidities, or median National Institute of Health Stroke Scale (NIHSS) scores between the ATA visualized (n = 47) versus non-visualized (n = 55) cohort, and no significant differences in baseline Alberta Stroke Program Early Computed Tomography (ASPECT) scores, post-intervention TICI scores, or interval from last known well to revascularization. There was a strong trend in functional independent outcome (mRS ≤ 2) for patients with ATA visualization (63.8% vs. 45.5%, p = 0.064). Conclusion For patients presenting to non-thrombectomy centers without CT perfusion capability, ATA visualization should be further investigated as an outcome predictor, given its association with functional independence after successful recanalization. This article was previously presented as a meeting abstract at the 2021 International Stroke Conference on March 17-19, 2021.

Reversible cerebral vasoconstriction syndrome successfully treated by intrathecal nicardipine.

Reversible cerebral vasoconstriction syndrome (RCVS) presents with a thunderclap headache, often prompting brain imaging. Most patients fully recover with supportive care and time, but oral calcium channel blockers are often used in patients with severe vasoconstriction. In this case report, we present a patient with severe vasoconstriction leading to weakness refractory to oral calcium channel blockers. Intrathecal nicardipine was administered via an external ventricular drain and the patient subsequently showed improvement of her weakness and significant improvement of vasospasm on Computed Tomography Angiography. We suggest further studies to determine the efficacy of intrathecal nicardipine in patients with RCVS not responsive to oral calcium channel blockers.

Outcomes After Decompressive Craniectomy for Ischemic Stroke: A Volumetric Analysis.

BACKGROUND: Decompressive hemicraniectomy (DHC) is a treatment of space-occupying hemispheric infarct. Current surgical guidelines use criteria of age <60 years and surgery within 48 hours of stroke onset. OBJECTIVE: The purpose of this study was to evaluate the neurologic outcome after DHC and evaluate the relationship of stroke volume and outcomes. METHODS: A retrospective review was performed of patients undergoing DHC for cerebral infarct from 2016 to 2019. Unfavorable outcome was defined as modified Rankin Scale (mRS) score >3. Patients with precraniectomy magnetic resonance imaging were selected as a subset for volumetric stroke volume analysis using RAPID software (iSchemaView, Redwood City, California), with stroke volume defined as apparent diffusion coefficient <620 on diffusion-weighted imaging. RESULTS: Fifty-two patients met the inclusion criteria. At 90 days, favorable outcome was achieved in 11 patients (21.2%), and 41 patients (78.8%) had unfavorable outcomes (15 [29%] died). Surgery after 48 hours, age >60 years, and multivessel distribution did not significantly affect 90-day mRS score (P = 0.091, 0.111, and 0.664, respectively). In volumetric subset analysis, 10 patients of 41 (31.3%) achieved favorable outcomes, and no patients with volume of infarct >280 mL had a favorable outcome. There was a trend of lower volumes associated with favorable outcomes, but this did not meet significance (favorable 207 ± 68.7 vs. unfavorable 262 ± 117.1; P = 0.163). CONCLUSIONS: Outcomes after DHC for malignant hemispheric infarct were not affected by current accepted guidelines. Volume of infarct may have an effect on outcome after DHC. Further research to aid in predicting which patients benefit from decompressive craniectomy is warranted.

Mild and Severe Obesity Reduce the Effectiveness of Lumbar Fusions: 1-Year Patient-Reported Outcomes in 8171 Patients.

BACKGROUND: Elevated body mass index (BMI) is a well-known risk factor for surgical complications in lumbar surgery. However, its effect on surgical effectiveness independent of surgical complications is unclear. OBJECTIVE: To determine increasing BMI's effect on functional outcomes following lumbar fusion surgery, independent of surgical complications. METHODS: We retrospectively analyzed a prospectively built, patient-reported, quality of life registry representing 75 hospital systems. We evaluated 1- to 3-level elective lumbar fusions. Patients who experienced surgical complications were excluded. A stepwise multivariate regression model assessed factors independently associated with 1-yr Oswestry Disability Index (ODI), preop to 1-yr ODI change, and achievement of minimal clinically important difference (MCID). RESULTS: A total of 8171 patients met inclusion criteria: 2435 with class I obesity (BMI 30-35 kg/m2), 1328 with class II (35-40 kg/m2), and 760 with class III (≥40 kg/m2). Increasing BMI was independently associated with worse 12-mo ODI (t = 8.005, P < .001) and decreased likelihood of achieving MCID (odds ratio [OR] = 0.977, P < .001). One year after surgery, mean ODI, ODI change, and percentage achieving MCID worsened with class I, class II, and class III vs nonobese cohorts (P < .001) in stepwise fashion. CONCLUSION: Increasing BMI is associated with decreased effectiveness of 1- to 3-level elective lumbar fusion, despite absence of surgical complications. BMI ≥ 30 kg/m2 is, therefore, a risk factor for both surgical complication and reduced benefit from lumbar fusion.