Correlating SPECT-CT activity in lumbar facet joints with response to lumbar medial branch and L5 dorsal ramus blocks.

Introduction: Lumbar facet arthritis is a significant source of back pain and impaired function that is amenable to treatment with medial branch radiofrequency neurotomy (RFN). Identifying appropriate patients for this treatment requires integration of information from the history, physical exam, and diagnostic imaging, but the current diagnostic standard for facet-mediated pain is positive comparative medial branch blocks (MBBs). Lumbar SPECT-CT has recently been evaluated as a potential predictor of positive MBBs with mixed results. The purpose of this retrospective analysis was to determine if the level of concordance between SPECT-CT uptake and facet joints targeted with MBB was associated with a positive block. Methods: A retrospective review was performed to identify all patients undergoing lumbar MBB within 12 months after having a lumbar SPECT-CT. Each procedure was classified into one of four categories based on the level of concordance between facet joints demonstrating increased 99mTc uptake on SPECT-CT and those being blocked: 1) Complete Concordance (all joints demonstrating increased uptake were blocked and no additional joints blocked); 2) Partial Concordance (all joints demonstrating increased uptake were blocked, with at least one joint not demonstrating increased uptake blocked); 3) Partial Discordance (at least one but not all joints demonstrating increased uptake were blocked); 4) Complete Discordance (all blocks performed at joints not demonstrating increased uptake). Statistical analysis was performed to determine if the level of concordance between increased uptake on SPECT-CT and joints undergoing MBB was associated with a positive block using cutoffs of 50 % and 80 % pain relief. Results: A total of 180 procedures were analyzed (23 % Complete Concordance, 22 % Partial Concordance, 31 % Partial Discordance, 24 % Complete Discordance) and all groups demonstrated improvement in pain Numeric Rating Scale (NRS) scores. There was no significant association between level of concordance and having a positive block using thresholds of 50 % pain relief, χ 2(3, N = 180) = 4.880, p = .181; or 80 % pain relief, χ 2(3, N = 180) = 1.272, p = .736. Conclusion: SPECT-CT findings do not accurately predict positive lumbar MBB but may provide valuable information that can be considered with other factors when deciding which joints to treat.

Correlating SPECT-CT activity in cervical facet joints with positive response to cervical medial branch blocks.

Introduction: Cervical facet arthritis is a significant source of neck pain and impaired function that is amenable to treatment with medial branch radiofrequency neurotomy (RFN). Identifying appropriate patients for this treatment requires integration of information from the history, physical exam and diagnostic imaging, but the current diagnostic standard for facet-mediated pain is positive comparative medial branch blockade (MBB). SPECT-CT has recently been evaluated as a potential predictor of positive medial branch blocks with mixed results. The purpose of this retrospective analysis was to determine if a relationship exists between increased uptake on SPECT-CT of a given cervical facet joint and a positive MBB. Methods: A retrospective review was performed to identify all patients undergoing cervical MBB within 12 months after having a cervical SPECT-CT. Each procedure was categorized as either Concordant (all facet joints demonstrating increased 99mTc uptake on SPECT-CT were blocked) or Discordant (at least one facet joint demonstrating increased 99mTc uptake on SPECT-CT was not blocked or block was performed in a patient that had no increased uptake on SPECT-CT). Statistical analysis was performed to determine if concordance between facet joints demonstrating increased uptake on SPECT-CT and those undergoing MBB was associated with a positive block using cutoffs of 50% and 80% pain relief. Results: A total of 43 procedures were analyzed (25% Concordant, 75% Discordant) and both groups demonstrated improvement in pain Numeric Rating Scale (NRS) scores. No significant association between concordance and positive MBB was identified at thresholds of 50% (p = .481) and 80% (p = 1.000) pain relief. Conclusion: SPECT-CT findings do not accurately predict positive cervical MBB but may provide valuable information that can be considered with other factors when deciding which joints to treat.

Spinal Anesthesia for Multilevel Awake Minimally Invasive Transforaminal Lumbar Interbody Fusion: Single-Center Experience.

BACKGROUND AND OBJECTIVES: Awake minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) generates minimal surrounding tissue damage and has been shown to be a safe, time-effective, and cost-reductive technique in single-level procedures. The purpose of this study was to advocate for the utilization of multilevel MIS-TLIF even in challenging cases as it has demonstrated positive outcomes. METHODS: Chart review was conducted for consecutive patients undergoing awake multilevel MIS-TLIF from 2020 to 2023. Various demographic, preoperative, and postoperative variables were collected and descriptively analyzed. RESULTS: Sixteen patients underwent multilevel awake MIS-TLIF at our institution during the specified period. Among them, 87.5% underwent a two-level procedure and 12.5% a three-level procedure. The median age ± IQR was 69.5 ± 11 years, with a slight male predominance (56.25%). Common comorbidities included hypertension (56.25%), obesity (37.5%), sleep apnea (25%), and type 2 diabetes (18.75%). The American Society of Anesthesiologists risk was 2 in 43.75% of patients and 3 in 56.25%. All patients presented pain, and 12.5% showed motor deficit. Intraoperative data showed a median of 196 minutes in the operating room where 156 ± 27.75 minutes corresponded to actual procedure time. The median estimated blood loss was 50 ± 70 cc. In the immediate postoperative period, 1 patient had nausea and emesis, and 1 reported fatigue. The median pain score during this period was 4.6 ± 2.03. Pain control medications were required for various patients, with methocarbamol (50%), hydromorphone (37.5%), and oxycodone (25%) being the most commonly prescribed in the postanesthesia care unit. No patient had new neurological deficits after the surgical intervention. The median length of stay was 2 days ±1.25. All patients were discharged with no complications. CONCLUSION: Multilevel awake MIS-TLIF emerges as a safe and effective technique for complex cases, enhancing patient quality of life with minimal blood loss and postoperative pain.

Minimally invasive posterior cervical foraminotomy versus the anterior transcorporeal approach for cervical radiculopathy: a systematic review and meta-analysis.

OBJECTIVE: Surgical decompression is often indicated for symptomatic cases of cervical radiculopathy. In the cervical spine, minimally invasive posterior cervical foraminotomy (MIS-PCF) and the anterior transcorporeal approach (ATCA) are modern techniques available to surgeons. This systematic review and single-arm meta-analysis aimed to assess surgical and patient-reported outcomes of MIS-PCF and ATCA for cervical radiculopathy. METHODS: A systematic review of the literature was conducted using 1) Ovid; 2) Epub Ahead of Print and In-Process, In-Data-Review & Other Non-Indexed Citations; and 3) Scopus databases, which reported outcomes following cervical decompression using MIS-PCF or the ATCA. Specifically, baseline characteristics, operative outcomes, and changes in visual analog scale (VAS) neck pain score were assessed. The quality of the studies was graded using the modified Newcastle-Ottawa Scale for observational studies. RESULTS: Forty studies with 1661 patients were identified. The comparative analysis of both techniques revealed no significant differences in complication (7%, 95% CI 5%-10%, p = 0.75) or reoperation rates (5%, 95% CI 3%-7%, p = 0.41). Additionally, there were no significant differences in estimated blood loss (55.39, 95% CI 44.62-66.16 ml, p = 0.55) or operative time (85.15, 95% CI 65.38-104.92 minutes, p = 0.05). The ATCA showed significantly greater improvement (p < 0.01) in VAS neck pain scores following surgery (ATCA point reduction 6.7, 95% CI 6.0-7.5 points vs MIS-PCF 3.0, 95% CI 1.0-5.0 points). CONCLUSIONS: The ATCA and MIS-PCF are effective modern techniques for the surgical treatment of radiculopathy. Both approaches showed comparable postoperative outcomes, including complication and reoperation rates. However, the ATCA was shown to provide significantly greater improvement in VAS neck pain scores.

Awake Robotic Minimally Invasive Transforaminal Lumbar Interbody Fusion Under Spinal Anesthesia: A Prospective Study with 1-Year Follow-up.

BACKGROUND: We describe our protocol and outcomes of awake robotic minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) under spinal anesthesia. METHODS: We conducted a prospective study of 10 consecutive patients undergoing awake robotic single-level MIS-TLIF with the Mazor X robot. We prospectively collected patient-reported outcomes (back and leg pain visual analog scale and Oswestry Disability Index) preoperatively at 1-month and 1-year follow-ups and assessed fusion and screw placement accuracy with a 1-year computed tomography (CT) scan. RESULTS: Median age was 61 years (interquartile range [IQR] = 57.7-66). Median body mass index was 27 kg/m2. No intraoperative complications were reported. Most (9/10) patients were discharged home, and 50% discharged on the day of surgery. Median length of stay was 16.5 hours (IQR = 5-35.5). Median follow-up was 12.5 months (IQR = 12-13.5), with 9 patients having at least 12-month follow-up, with CT scans documenting good screw placement (Gertzbein-Robbins grade A) and solid bony fusion. Median preoperative back pain visual analog scale score was 7.8 (IQR = 6.9-8) versus 1.5 (IQR = 0-3.2) at 1-month post operation, P < 0.01, and 0 (IQR = 0-1) at 1-year follow-up, P < 0.01; median preoperative leg pain 8 (IQR = 7.4-8) versus 0 (IQR = 0-1.2) at 1-month post operation, P < 0.01, and 0 (IQR = 0-2) at 1-year follow-up, P < 0.01; median preoperative Oswestry Disability Index 47.5 (IQR = 27.8-57.5) versus 4 (IQR = 0-16) at 1-month postoperation, P < 0.01, and 0 (IQR = 0-7) at 1-year follow-up, P < 0.01. Median preoperative disk height of the index level was 8 mm (IQR = 2.4-9.5) versus 11.4 mm (IQR = 9.2-11.2) postoperatively,P < 0.01. Median preoperative lordosis of the index level was 5 degrees (IQR = 3.4-8.5) versus 10.1 degrees (7.3-12.2) postoperatively, P < 0.01. CONCLUSIONS: Our study showed significant improvement in patient-reported outcomes at 1-month and 1-year follow-ups after awake robotic MIS-TLIF, as well as solid bony fusion on CT scans.

Change in spinal bone mineral density as estimated by Hounsfield units following osteoporosis treatment with romosozumab, teriparatide, denosumab, and alendronate: an analysis of 318 patients.

OBJECTIVE: The purpose of this study was to determine the effect of osteoporosis medications on opportunistic CT-based Hounsfield units (HU). METHODS: Spine and nonspine surgery patients were retrospectively identified who had been treated with romosozumab for 3 to 12 months, teriparatide for 3 to 12 months, teriparatide for > 12 months, denosumab for > 12 months, or alendronate for > 12 months. HU were measured in the L1-4 vertebral bodies. One-way ANOVA was used to compare the mean change in HU among the five treatment regimens. RESULTS: In total, 318 patients (70% women) were included, with a mean age of 69 years and mean BMI of 27 kg/m2. There was a significant difference in mean HU improvement (p < 0.001) following treatment with romosozumab for 3 to 12 months (n = 32), teriparatide for 3 to 12 months (n = 30), teriparatide for > 12 months (n = 44), denosumab for > 12 months (n = 123), and alendronate for > 12 months (n = 100). Treatment with romosozumab for a mean of 10.5 months significantly increased the mean HU by 26%, from a baseline of 85 to 107 (p = 0.012). Patients treated with teriparatide for > 12 months (mean 23 months) experienced a mean HU improvement of 25%, from 106 to 132 (p = 0.039). Compared with the mean baseline HU, there was no significant difference after treatment with teriparatide for 3 to 12 months (110 to 119, p = 0.48), denosumab for > 12 months (105 to 107, p = 0.68), or alendronate for > 12 months (111 to 113, p = 0.80). CONCLUSIONS: Patients treated with romosozumab for a mean of 10.5 months and teriparatide for a mean of 23 months experienced improved spinal bone mineral density as estimated by CT-based opportunistic HU. Given the shorter duration of effective treatment, romosozumab may be the preferred medication for optimization of osteoporotic patients in preparation for elective spine fusion surgery.

Proton versus photon adjuvant radiotherapy: a multicenter comparative evaluation of recurrence following spinal chordoma resection.

OBJECTIVE: Chordomas are rare tumors of the skull base and spine believed to arise from the vestiges of the embryonic notochord. These tumors are locally aggressive and frequently recur following resection and adjuvant radiotherapy. Proton therapy has been introduced as a tissue-sparing option because of the higher level of precision that proton-beam techniques offer compared with traditional photon radiotherapy. This study aimed to compare recurrence in patients with chordomas receiving proton versus photon radiotherapy following resection by applying tree-based machine learning models. METHODS: The clinical records of all patients treated with resection followed by adjuvant proton or photon radiotherapy for chordoma at Mayo Clinic were reviewed. Patient demographics, type of surgery and radiotherapy, tumor recurrence, and other variables were extracted. Decision tree classifiers were trained and tested to predict long-term recurrence based on unseen data using an 80/20 split. RESULTS: Fifty-three patients with a mean ± SD age of 55.2 ± 13.4 years receiving surgery and adjuvant proton or photon therapy to treat chordoma were identified; most patients were male. Gross-total resection was achieved in 54.7% of cases. Proton therapy was the most common adjuvant radiotherapy (84.9%), followed by conventional or external-beam radiation therapy (9.4%) and stereotactic radiosurgery (5.7%). Patients receiving proton therapy exhibited a 40% likelihood of having recurrence, significantly lower than the 88% likelihood observed in those treated with nonproton therapy. This was confirmed on logistic regression analysis adjusted for extent of tumor resection and tumor location, which revealed that proton adjuvant radiotherapy was associated with a decreased risk of recurrence (OR 0.1, 95% CI 0.01-0.71; p = 0.047) compared with photon therapy. The decision tree algorithm predicted recurrence with an accuracy of 90% (95% CI 55.5%-99.8%), with the lowest risk of recurrence observed in patients receiving gross-total resection with adjuvant proton therapy (23%). CONCLUSIONS: Following resection, adjuvant proton therapy was associated with a lower risk of chordoma recurrence compared with photon therapy. The described machine learning models were able to predict tumor progression based on the extent of tumor resection and adjuvant radiotherapy modality used.

Single-Photon Emission Computed Tomography (SPECT-CT) as a Predictor of Pain Generators in Patients Undergoing Anterior Cervical Discectomy and Fusion (ACDF) for Axial Cervical Pain.

BACKGROUND: Axial neck pain is often associated with cervical instability, and surgical options are often reserved for patients with either neurological compromise or deformity of the spine. However, cervical facet arthropathy is often implicated with instability and the location of painful generators is often difficult to ascertain. Single-photon emission computed tomography (SPECT-CT) presents an adjunct to conventional imaging in the workup of patients with suspected facetogenic pain. We aimed to report our experience with patients undergoing anterior cervical discectomy and fusion (ACDF) guided by SPECT-CT for axial cervical pain. METHODS: We retrospectively identified all cases undergoing ACDF that presented with axial neck pain where correlating SPECT-CT high metabolism areas were identified. Patients were treated at a tertiary care institution between January 2018 and January 2021. Patients with positive radiotracer uptake pre-operatively were compared with patients undergoing ACDF without uptake on SPECT-CT. The pre- and post-operative patients who reported neck pain at one year were compared. RESULTS: Thirty-five patients were included in this retrospective cohort. The median pre- and post-intervention (at one-year follow-up) visual analog score (VAS) of patients undergoing ACDF without uptake on SPECT-CT was 7 and 3 (p<0.01), while the pre- and post-VAS for patients undergoing surgery with positive uptake on SPECT-CT was 8.5 and 0 (p<0.01). Improvement was significantly larger for patients undergoing SPECT-CT-guided ACDF (p=0.02). At one year after surgery, none of the assessed patients required additional surgical intervention. CONCLUSION: This case series represents the experience of our group to date with patients undergoing SPECT-CT-guided ACDF with results suggesting potential benefit in guiding fusion.

The Effect of C2 Muscular Exposure Technique on Radiographic and Clinical Outcomes After C2-T2 Posterior Cervical Fusion.

STUDY DESIGN: Retrospective cohort analysis. OBJECTIVE: To determine whether the C2 exposure technique was a predictor of change in cervical alignment and patient-reported outcomes measures (PROMs) after posterior cervical decompression and fusion (PCDF) for degenerative indications. BACKGROUND: In PCDF handling of the C2 posterior paraspinal musculature during the operative approach varies by surgeon technique. To date, no studies have investigated whether maintenance of the upper cervical semispinalis cervicis attachments as compared with complete reflection of upper cervical paraspinal musculature from the posterior bony elements is associated with superior radiographic and clinical outcomes after PCDF. PATIENTS AND METHODS: All adult patients who underwent C2-T2 PCDF for myelopathy or myeloradiculopathy at multi-institutional academic centers between 2013 and 2020 were retrospectively identified. Patients were dichotomized by the C2 exposure technique into semispinalis preservation or midline muscular reflection groups. Preoperative and short and long-term postoperative radiographic outcomes (upper cervical alignment, global alignment, and fusion status) and PROMs (Visual Analog Scale-Neck, Neck Disability Index, and Short Form-12) were collected. Univariate analysis compared patient factors, radiographic measures, and PROMs across C2 exposure groups. RESULTS: A total of 129 patients met the inclusion/exclusion criteria (73 muscle preservation and 56 muscle reflection). Patients in the muscular preservation group were on average younger (P= 0.005) and more likely to have bone morphogenic protein (P< 0.001) and C2 pars screws (P= 0.006) used during surgery. Preoperative to postoperative changes in C2 slope, C2 tilt, C2-C3 segmental lordosis, C2-C3 listhesis, C0-C2 Cobb angle, proximal junctional kyphosis, ADI, C1 lamina-occiput distance, C2 sagittal vertical axis, C2-C7 lordosis, and PROMs at all follow-up intervals did not vary significantly by C2 exposure technique. Likewise, there were no significant differences in fusion status, C2-C3 pseudoarthrosis, C2 screw loosening, and complication and revision rates between C2 exposure groups. CONCLUSIONS: Preservation of C2 semispinalis attachments versus muscular reflection did not significantly impact cervical alignment, clinical outcomes, or proximal junction complications in long-segment PCDF. LEVEL OF EVIDENCE: Level III.

From the Operating Room to the Laboratory: Role of the Neuroscience Tissue Biorepository in the Clinical, Translational, and Basic Science Research Pipeline.

OBJECTIVE: To establish a neurologic disorder-driven biospecimen repository to bridge the operating room with the basic science laboratory and to generate a feedback cycle of increased institutional and national collaborations, federal funding, and human clinical trials. METHODS: Patients were prospectively enrolled from April 2017 to July 2022. Tissue, blood, cerebrospinal fluid, bone marrow aspirate, and adipose tissue were collected whenever surgically safe. Detailed clinical, imaging, and surgical information was collected. Neoplastic and nonneoplastic samples were categorized and diagnosed in accordance with current World Health Organization classifications and current standard practices for surgical pathology at the time of surgery. RESULTS: A total of 11,700 different specimens from 813 unique patients have been collected, with 14.2% and 8.5% of patients representing ethnic and racial minorities, respectively. These include samples from a total of 463 unique patients with a primary central nervous system tumor, 88 with metastasis to the central nervous system, and 262 with nonneoplastic diagnoses. Cerebrospinal fluid and adipose tissue dedicated banks with samples from 130 and 16 unique patients, respectively, have also been established. Translational efforts have led to 42 new active basic research projects; 4 completed and 6 active National Institutes of Health-funded projects; and 2 investigational new drug and 5 potential Food and Drug Administration-approved phase 0/1 human clinical trials, including 2 investigator initiated and 3 industry sponsored. CONCLUSION: We established a comprehensive biobank with detailed notation with broad potential that has helped us to transform our practice of research and patient care and allowed us to grow in research and clinical trials in addition to providing a source of tissue for new discoveries.

The Predictors of Incidental Durotomy in Patients Undergoing Pedicle Subtraction Osteotomy for the Correction of Adult Spinal Deformity.

Background: Pedicle subtraction osteotomy (PSO) is a powerful tool for sagittal plane correction in patients with rigid adult spinal deformity (ASD); however, it is associated with high intraoperative blood loss and the increased risk of durotomy. The objective of the present study was to identify intraoperative techniques and baseline patient factors capable of predicting intraoperative durotomy. Methods: A tri-institutional database was retrospectively queried for all patients who underwent PSO for ASD. Data on baseline comorbidities, surgical history, surgeon characteristics and intraoperative maneuvers were gathered. PSO aggressiveness was defined as conventional (Schwab 3 PSO) or an extended PSO (Schwab type 4). The primary outcome of the study was the occurrence of durotomy intraoperatively. Univariable analyses were performed with Mann-Whitney U tests, Chi-squared analyses, and Fisher's exact tests. Statistical significance was defined by p < 0.05. Results: One hundred and sixteen patients were identified (mean age 61.9 ± 12.6 yr; 44.8% male), of whom 51 (44.0%) experienced intraoperative durotomy. There were no significant differences in baseline comorbidities between those who did and did not experience durotomy, with the exception that baseline weight and body mass index were higher in patients who did not suffer durotomy. Prior surgery (OR 2.73; 95% CI [1.13, 6.58]; p = 0.03) and, more specifically, prior decompression at the PSO level (OR 4.23; 95% CI [1.92, 9.34]; p < 0.001) was predictive of durotomy. A comparison of surgeon training showed no statistically significant difference in durotomy rate between fellowship and non-fellowship trained surgeons, or between orthopedic surgeons and neurosurgeons. The PSO level, PSO aggressiveness, the presence of stenosis at the PSO level, nor the surgical instrument used predicted the odds of durotomy occurrence. Those experiencing durotomy had similar hospitalization durations, rates of reoperation and rates of nonroutine discharge. Conclusions: In this large multisite series, a history of prior decompression at the PSO level was associated with a four-fold increase in intraoperative durotomy risk. Notably the use of extended (versus) standard PSO, surgical technique, nor baseline patient characteristics predicted durotomy. Durotomies occurred in 44% of patients and may prolong operative times. Additional prospective investigations are merited.

Frailty as a Predictor of Postoperative Morbidity and Mortality in Patients Aged 80 Years and Older Undergoing Instrumented Fusion.

BACKGROUND AND OBJECTIVES: Degenerative spine disease is a leading cause of disability, with increasing prevalence in the older patients. While age has been identified as an independent predictor of outcomes, its predictive value is limited for similar older patients. Here, we aimed to determine the most predictive frailty score of adverse events in patients aged 80 and older undergoing instrumented lumbar fusion. METHODS: We proceeded with a multisite (3 tertiary academic centers) retrospective review including patients undergoing instrumented fusion aged 80 and older from January 2010 to present. A composite end point encompassing 30-day return to operating room, readmission, and mortality was created. We estimated the area under the receiver operating characteristic curve for frailty scores (Modified Frailty Index-5 [MFI-5], Modified Frailty Index-11 [MFI-11], and Charlson Comorbidity Index [CCI]) in relation to that composite score. In addition, we estimated the association between each score and the composite end point by means of logistic regression. RESULTS: A total of 153 patients with an average age of 85 years at the time of surgery were included. We observed a 30-day readmission rate of 11.1%, reoperation of 3.9%, and mortality of 0.6%. The overall rate of the composite end point at 30 days was 25 (15.1%). The AUC for MFI-5 was 0.597 (0.501-0.693), for MFI-11 was 0.620 (0.518-0.723), and for CCI was 0.564 (0.453-0.675). The association between the scores and composite end point did not reach statistical significance for MFI-5 (odds ratio [OR] = 1.45 [0.98-2.15], P = .061) and CCI (OR = 1.13 [0.97-1.31], P = .113) but was statistically significant for MFI-11 (OR = 1.46 [1.07-2.00], P = .018). CONCLUSION: This is the largest study comparing frailty index scores in octogenarians undergoing instrumented lumbar fusion. Our findings suggest that while MFI-11 score correlated with adverse events, the predictive ability of existing scores remains limited, highlighting the need for better approaches to identify select patients at age extremes.

General Versus Nongeneral Anesthesia for Spinal Surgery: A Comparative National Analysis of Reimbursement Trends Over 10 Years.

BACKGROUND AND OBJECTIVES: Nongeneral anesthesia (non-GA) spine surgery is growing in popularity and has facilitated earlier postoperative recovery, reduced cost, and fewer complications compared with spine surgery under general anesthesia (GA). Changes in reimbursement policies have been demonstrated to correlate with clinical practice; however, they have yet to be studied for GA vs non-GA spine procedures. We aimed to investigate trends in physician reimbursement for GA vs non-GA spine surgery in the United States. METHODS: We queried the ACS-NSQIP for GA and non-GA (regional, epidural, spinal, and anesthesia care/intravenous sedation) spine surgeries during 2011-2020. Work relative value units per operative hour (wRVUs/h) were retrieved for decompression or stabilization of the cervical, thoracic, and lumbar spine. Propensity score matching (1:1) was performed using all baseline variables. RESULTS: We included 474 706 patients who underwent spine decompression or stabilization procedures. GA was used in 472 248 operations, whereas 2458 operations were non-GA. The proportion of non-GA spine operations significantly increased during the study period. Operative times ( P < .001) and length of stays ( P < .001) were shorter in non-GA when compared with GA procedures. Non-GA lumbar procedures had significantly higher wRVUs/h when compared with the same procedures performed under GA (decompression; P < .001 and stabilization; P = .039). However, the same could not be said about cervicothoracic procedures. Lumbar decompression surgeries using non-GA witnessed significant yearly increase in wRVUs/h ( P < .01) contrary to GA ( P = .72). Physician reimbursement remained stable for procedures of the cervical or thoracic spine regardless of the anesthesia. CONCLUSION: Non-GA lumbar decompressions and stabilizations are associated with higher and increasing reimbursement trends (wRVUs/h) compared with those under GA. Reimbursement for cervical and thoracic surgeries was equal regardless of the type of anesthesia and being relatively stable during the study period. The adoption of a non-GA technique relative to the GA increased significantly during the study period.

What Factors Predict the Development of Neurologic Deficits Following Resection of Intramedullary Spinal Cord Tumors: A Multi-Center Study.

BACKGROUND: Intramedullary spinal cord tumors are challenging to resect, and their postoperative neurological outcomes are often difficult to predict, with few studies assessing this outcome. METHODS: We reviewed the medical records of all patients surgically treated for Intramedullary spinal cord tumors at our multisite tertiary care institution (Mayo Clinic Arizona, Mayo Clinic Florida, Mayo Clinic Rochester) between June 2002 and May 2020. Variables that were significant in the univariate analyses were included in a multivariate logistic regression. "MissForest" operating on the Random Forest algorithm, was used for data imputation, and K-prototype was used for data clustering. Heatmaps were added to show correlations between postoperative neurological deficit and all other included variables. Shapley Additive exPlanations were implemented to understand each feature's importance. RESULTS: Our query resulted in 315 patients, with 160 meeting the inclusion criteria. There were 53 patients with astrocytoma, 66 with ependymoma, and 41 with hemangioblastoma. The mean age (standard deviation) was 42.3 (17.5), and 48.1% of patients were women (n = 77/160). Multivariate analysis revealed that pathologic grade >3 (OR = 1.55; CI = [0.67, 3.58], P = 0.046 predicted a new neurological deficit. Random Forest algorithm (supervised machine learning) found age, use of neuromonitoring, histology of the tumor, performing a midline myelotomy, and tumor location to be the most important predictors of new postoperative neurological deficits. CONCLUSIONS: Tumor grade/histology, age, use of neuromonitoring, and myelotomy type appeared to be most predictive of postoperative neurological deficits. These results can be used to better inform patients of perioperative risk.

Comparative outcomes of awake spine surgery under spinal versus general anesthesia: a comprehensive systematic review and meta-analysis.

BACKGROUND: Awake surgery, under spinal anesthesia (SA), is an alternative to surgery under general anesthesia (GA), in neurological and spine surgery. In the literature, there seem to be some evidence supporting benefits associated with the use of this anesthetic modality, as compared to GA. Currently, there is a notable lack of updated and comprehensive review addressing the complications associated with both awake SA and GA in spine surgery. We hence aimed to perform a systematic review of the literature and meta-analysis on the topic. METHODS: A systematic search was conducted to identify studies that assessed SA in spine surgery from database inception to April 14, 2023, in PubMed, Medline, Embase, and Cochrane databases. Outcomes of interest included estimated blood loss, length of hospital stay, operative time, and overall complications. Meta-analysis was conducted using random effects models. RESULTS: In total, 38 studies that assessed 7820 patients were included. The majority of the operations that were treated with SA were single-level lumbar cases. Awake patients had significantly shorter lengths of hospital stay (Mean difference (MD): - 0.40 days; 95% CI - 0.64 to - 0.17) and operative time (MD: - 19.17 min; 95% CI - 29.68 to - 8.65) compared to patients under GA. The overall complication rate was significantly higher in patients under GA than SA (RR, 0.59 [95% CI 0.47-0.74]). Patients under GA had significantly higher rates of postoperative nausea/vomiting RR, 0.60 [95% CI 0.39-0.90]) and urinary retention (RR, 0.61 [95% CI 0.37-0.99]). CONCLUSIONS: Patients undergoing awake spine surgery under SA had significantly shorter operations and hospital stays, and fewer rates of postoperative nausea and urinary retention as compared to GA. In summary, awake spine surgery offers a valid alternative to GA and added benefits in terms of postsurgical complications, while being associated with relatively low morbidity.

Association between immunohistochemical markers and tumor progression following resection of spinal chordomas: a multicenter study.

OBJECTIVE: Chordomas are slow-growing tumors derived from notochord remnants. Despite margin-negative excision and postoperative radiation therapy, spinal chordomas (SCs) often progress. The potential of immunohistochemical (IHC) markers, such as epithelial membrane antigen (EMA), combined with machine learning algorithms to predict long-term (≥ 12 months) postoperative tumor progression, has been understudied. The authors aimed to identify IHC markers using trained tree-based algorithms to predict long-term (≥ 12 months) postoperative tumor progression. METHODS: The authors reviewed the records of patients who underwent resection of SCs between January 2017 and June 2021 across the Mayo Clinic enterprise. Demographics, type of treatment, histopathology, and other relevant clinical factors were abstracted from each patient's record. Low tumor progression was defined as more than a 94.3-mm3 decrease in the tumor size at the latest radiographic follow-up. Decision trees and random forest classifiers were trained and tested to predict the long-term volumetric progression after an 80/20 data split. RESULTS: Sixty-two patients diagnosed with and surgically treated for SC were identified, of whom 31 were found to have a more advanced tumor progression based on the tumor volume change cutoff of 94.3 mm3. The mean age was 54.3 ± 13.8 years, and most patients were male (62.9%) and White (98.4%). The most common treatment modality was subtotal resection with radiation therapy (35.5%), with proton beam therapy being the most common (71%). Most SCs were sacrococcygeal (41.9%), followed by cervical (32.3%). EMA-positive SCs had a postoperative progression risk of 67%. Pancytokeratin-positive SCs had a progression rate of 67%; however, patients with S100 protein-positive SCs had a 54% risk of progression. The accuracy of this model in predicting the progression of unseen test data was 66%. Pancytokeratin (mean minimal depth = 1.57), EMA (mean minimal depth = 1.58), cytokeratin A1/A3 (mean minimal depth = 1.59), and S100 protein (mean minimal depth = 1.6) predicted the long-term volumetric progression. Multiway variable importance plots show the relative importance of the top 10 variables based on three measures of varying significance and their predictive role. CONCLUSIONS: These IHC variables with tree-based machine learning tools successfully demonstrate a high capacity to identify a patient's tumor progression pattern with an accuracy of 66%. Pancytokeratin, EMA, cytokeratin A1/A3, and S100 protein were the IHC drivers of a low tumor progression. This shows the power of machine learning algorithms in analyzing and predicting outcomes of rare conditions in a small sample size.

Bone-anchored annular closure device leading to histiocytic-inflammation-induced neuropathy with resolution after removal: a case report.

PURPOSE: To determine and report the underlying cause of local inflammation causing recurrent neuropathy and multiple operations in a patient with a Barricaid® device. METHODS: After removal of this patient's Barricaid® device, we sent local inflammatory tissue to pathology for histochemical analysis. Upon discovery of giant cells formation with polarizable foreign bodies, we performed a literature review regarding the Barricaid® device and its elements. RESULTS: After two previous operations and three trials of conservative management, the presented patient underwent an L5/S1 TLIF with removal of her previously installed Barricaid® device. There were no signs of device instability/failure nor were there obvious signs of infection. Inflamed tissue proximal to the Barricaid® device was discovered, debrided, and sample sent to pathology. Removal of the Barricaid® device led to subsequent and durable relief of her symptoms. During review of this case, we discovered the polyethylene terephthalate (PET) weave used in the Barricaid® device is known to induce foreign body reactions, and this precise finding was seen in the majority of animal data submitted to the FDA for the device's acceptance. CONCLUSION: Given the constellation of this patient's symptoms, imaging, intraoperative, and pathology findings, previously published reports, and pre-approval data submitted to the FDA, we conclude that the inflammatory response to the PET weave in this patient's Barricaid® device was the ultimate cause of her continued neuropathy despite multiple prior surgical interventions.

Immunohistochemical markers predicting long-term recurrence following clival and spinal chordoma resection: a multicenter study.

OBJECTIVE: Chordomas are rare tumors from notochordal remnants and account for 1%-4% of all primary bone malignancies, often arising from the clivus and sacrum. Despite margin-negative resection and postoperative radiotherapy, chordomas often recur. Further, immunohistochemical (IHC) markers have not been assessed as predictive of chordoma recurrence. The authors aimed to identify the IHC markers that are predictive of postoperative long-term (≥ 1 year) chordoma recurrence by using trained multiple tree-based machine learning (ML) algorithms. METHODS: The authors reviewed the records of patients who had undergone treatment for clival and spinal chordomas between January 2017 and June 2021 across the Mayo Clinic enterprise (Minnesota, Florida, and Arizona). Demographics, type of treatment, histopathology, and other relevant clinical factors were abstracted from each patient record. Decision tree and random forest classifiers were trained and tested to predict long-term recurrence based on unseen data using an 80/20 split. RESULTS: One hundred fifty-one patients diagnosed and treated for chordomas were identified: 58 chordomas of the clivus, 48 chordomas of the mobile spine, and 45 chordomas sacrococcygeal in origin. Patients diagnosed with cervical chordomas were the oldest among all groups (58 ± 14 years, p = 0.009). Most patients were male (n = 91, 60.3%) and White (n = 139, 92.1%). Most patients underwent resection with or without radiation therapy (n = 129, 85.4%). Subtotal resection followed by radiation therapy (n = 51, 33.8%) was the most common treatment modality, followed by gross-total resection then radiation therapy (n = 43, 28.5%). Multivariate analysis showed that S100 and pan-cytokeratin are more likely to predict the increase in the risk of postoperative recurrence (OR 3.67, 95% CI 1.09-12.42, p= 0.03; and OR 3.74, 95% CI 0.05-2.21, p = 0.02, respectively). In the decision tree analysis, a clinical follow-up > 1897 days was found in 37% of encounters and a 90% chance of being classified for recurrence (accuracy = 77%). Random forest analysis (n = 500 trees) showed that patient age, type of surgical treatment, location of tumor, S100, pan-cytokeratin, and EMA are the factors predicting long-term recurrence. CONCLUSIONS: The IHC and clinicopathological variables combined with tree-based ML tools successfully demonstrated a high capacity to identify recurrence patterns with an accuracy of 77%. S100, pan-cytokeratin, and EMA were the IHC drivers of recurrence. This shows the power of ML algorithms in analyzing and predicting outcomes of rare conditions of a small sample size.

Effect of race, sex, and socioeconomic factors on overall survival following the resection of intramedullary spinal cord tumors.

INTRODUCTION: Intramedullary spinal cord tumors (IMSCTs) account for 2-4% of all primary CNS tumors. Given their low prevalence and the intricacy of their diagnosis and management, it is critical to address the surrounding racial and socioeconomic factors that impact the care of patients with IMSCTs. This study aimed to investigate the association between race and socioeconomic factors with overall 5 year mortality following the resection of IMSCTs. METHODS: The study used the National Cancer Database to retrospectively analyze patients who underwent resection of IMSCTs from 2004 to 2017. Patients were divided into four cohorts by race/ethnicity, facility type, insurance, median income quartiles, and living area. The primary outcome of interest was 5 year survival, and secondary outcomes included postoperative length of stay and 30 day readmission. Descriptive and multivariable analyses were used to identify independent factors associated with mortality, with statistical significance assessed at a 2-sided p < 0.05. RESULTS: We evaluated the patient characteristics and outcomes for 8,028 patients who underwent surgical treatment for IMSCTs between 2004 and 2017. Most patients were white males (52.4%) with a mean age of 44 years where 7.17% of patients were Black, 7.6% were Hispanic, and 3% were Asian. Most were treated in an academic/research program (72.4%) and had private insurance (69.2%). Black patients had a higher odd of 5 year mortality (OR 1.4; 95% CI 1.1 to 1.77; p = 0.04) compared to white patients, while no significant differences in mortality were observed among other races. Factors associated with lower odds of mortality included being female (OR 0.89; 95% CI 0.78 to 1.02; p < 0.01), receiving treatment in an academic/research program (OR 0.51; 95% CI 0.33 to 0.79; p = 0.04), having private insurance (OR 0.65; 95% CI 0.45 to 0.93; p = 0.02), and having higher income quartiles (OR 0.77; 95% CI 0.62 to 0.96; p = 0.02). CONCLUSION: Our study sheds light on the healthcare disparities that exist in the surgical management of IMSCTs. Our findings indicate that race, sex, socioeconomic status, and treatment facility are independent predictors of 5 year mortality, with Black patients, males, those with lower socioeconomic status, and those treated at non-academic centers experiencing significantly higher mortality rates. These alarming disparities underscore the urgent need for policymakers and researchers to address the underlying factors contributing to these discrepancies and provide equal access to high-quality surgical care for patients with IMSCTs.

Impact of postoperative fatigue following minimally-invasive lumbar spine surgery.

BACKGROUND: Postoperative fatigue is a distressing symptom and can have a major impact on the patient's quality of life after surgery. We investigate the extent of postoperative fatigue following minimally invasive spine surgery under general anesthesia (GA), and its impact on patients' quality of life (QOL) and activities of daily living (ADLs). METHODS: We surveyed patients that underwent minimally-invasive lumbar spine surgery under GA within the previous year. A five-point Likert scale ("very much", "quite a bit", "somewhat", "a little bit", "not at all") was used to assess the extent of fatigue during the first postoperative month, its impact on QOL, and ADLs. RESULTS: The survey was completed by 100 patients, 61% were male, mean age 64.6 ± 12.5 years, 31% underwent MIS-TLIF, 69% lumbar laminectomy. During the first postoperative month 45% of patients referred significant fatigue ("very much" or "quite a bit"); for 31% of patients fatigue significantly impacted their QOL; significantly limited their ADLs in 43% of patients. MIS-TLIF was associated with higher rate of postoperative fatigue compared to laminectomy (61.3% versus 37.7%, p = 0.02). Patients 65 years old or older had higher rates of fatigue compared to younger patients (55.6% versus 32.6%, p = 0.02). We did not observe a significant difference in postoperative fatigue between male and female patients. CONCLUSIONS: Our study revealed a substantial incidence of postoperative fatigue in patients that underwent minimally-invasive lumbar spine surgery under GA, with a significant impact on QOL and ADLs. There is a need to research new strategies to reduce fatigue after spine surgery.