Lo, Sheng-Fu Larry

OBJECTIVE Intramedullary spinal cord tumors (IMSCTs) are typically treated with maximal safe resection, during which neurosurgeons often monitor for neurological injury using muscle motor evoked potential (mMEP) and direct wave (D-wave) neuromonitoring. The predictive value of changes in D-waves for identifying motor outcomes is underexplored. This study evaluated the utility of D-waves for predicting postoperative motor deficits. METHODS Patients who underwent resection of a primary IMSCT with mMEP neuromonitoring from 2003 to 2023 at a tertiary care hospital were identified. Patients who underwent D-wave monitoring in addition to mMEP monitoring were compared to those who underwent mMEP monitoring alone using the Mann-Whitney U-test, chi-square test, and Fisher’s exact test. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of D-wave and mMEP monitoring for identifying new neurological deficits immediately postoperatively and at 1 month, 6 months, and last follow-up were calculated. RESULTS After matching, 125 patients were included (median age 42.0 years; 57.6% male; median follow-up 34.0 months), of whom 88 had both mMEP and D-wave data. The most common pathologies were ependymoma (64.0%) and astrocytoma (17.6%). Patients who did and did not undergo D-wave neuromonitoring had similar preoperative neurological function, primary pathology, tumor grade, and tumor location. D-wave use was associated with increased gross-total resection (88.6% vs 64.9%, p = 0.002) and reduced mortality (5.7% vs 24.3%, p = 0.007), length of stay (5.0 vs 6.0 days, p = 0.033), and 30-day readmission (2.3% vs 13.5%, p = 0.013) and reoperation (1.1% vs 10.8%, p = 0.012). At the 6-month follow-up, D-wave monitoring alone was superior to mMEP and combination monitoring for detecting new motor deficits. D-wave monitoring had peak sensitivity (77.8%) and NPV (96.5%) at 6 months and peak specificity (95.8%) and PPV (76.9%) in the immediate postoperative period. CONCLUSIONS D-wave monitoring was associated with reduced mortality and was more accurate than mMEP monitoring alone or combination monitoring for detecting new postoperative neurological deficits. Further prospective studies are needed to validate these results.

With continued improvements in systemic cancer therapies, there has been an increase in the survivorship of patients with spinal metastases. However, many patients with spinal metastases are frail and may not be able to tolerate the morbidity of open surgery. For these patients, percutaneous ablation techniques offer a minimally invasive approach that can facilitate local tumor control and pain relief. Here we describe the currently employed modalities—radiofrequency ablation (RFA), microwave ablation (MWA), cryoablation, and laser interstitial thermal therapy (LITT)—summarize the clinical support for their use, and overview the relative risks and benefits for each. All these technologies offer to help improve local tumor control and improve oncologic pain associated with vertebral metastases, and they have become a staple of multidisciplinary spine metastasis care at many centers. As clinical experience with these technologies continues to grow, their use will likely become more widely adopted, and so understanding of their indications, risks, and benefits will become increasingly important to the practicing spine oncologist.

BACKGROUND AND OBJECTIVES: The Risk Analysis Index (RAI) is a comprehensive assessment of frailty for predicting neurosurgical outcomes. The aim of this study was to assess whether frailty, measured by a modified RAI (mRAI), was an independent predictor of adverse events (AEs), nonroutine discharge (NRD), and in-hospital mortality for patients with acute cervical spinal cord injuries (SCIs). METHODS: A retrospective cohort study was performed using the American College of Surgeons Trauma Quality Programs database. Adult patients with acute cervical SCI from 2016 to 2022 were stratified by mRAI score into 3 groups: Robust (mRAI 0-10), Frail (mRAI 11-20), and Very Frail (mRAI ≥21). Patient demographics, comorbidities, injury type, diagnostic and treatment modality, AEs, and in-hospital mortality were assessed. A multivariate logistic regression analysis was used to identify independent predictors of AEs, NRD, and in-hospital mortality. RESULTS: 71 048 patients were stratified by mRAI score: 59 796 Robust (84.2%), 9558 Frail (13.5%), and 1694 Very Frail (2.4%). The proportion of SCIs secondary to a fall (Robust: 44.1% vs Frail: 70.2% vs Very Frail: 82.3%; P < .001) and AEs (Robust: 21.5% vs Frail: 24.4% vs Very Frail: 25.0%; P < .001) significantly increased with frailty. Very Frail patients experienced higher NRDs (Robust: 72.3% vs Frail: 85.2% vs Very Frail: 91.0%; P < .001) and in-hospital mortality (Robust: 10.9% vs Frail: 18.3% vs Very Frail: 29.2%; P < .001). On multivariate regression analysis, both Frail (odds ratio [OR]: 1.42; 95% CI: 1.25-1.61; P < .001) and Very Frail (OR: 2.09; 95% CI: 1.46-2.99; P < .001) mRAI scores predicted NRD, but only Frail mRAI score (OR: 1.12; 95% CI: 1.05-1.21; P = .001) was significantly associated with AEs. In addition, Frail (OR: 1.50; 95% CI: 1.36-1.65; P < .001) and Very Frail (OR: 2.79; 95% CI: 2.36-3.29; P < .001) mRAI scores were independent predictors of in-hospital mortality. CONCLUSION: Our study suggests that mRAI may be used to assess morbidity and mortality in patients presenting with spinal cord injury.

OBJECTIVE Management of locally invasive colorectal carcinoma at any stage currently involves surgical excision followed by chemoradiotherapy; however, the prognosis is poor, with a 5-year overall survival (OS) of only 5%. Failure to achieve gross-total resection is associated with poorer OS, and patients with residual tumor postresection (R1 or R2 resection) have a median OS of 7 months compared with 23 months in those who undergo resection with negative margins (R0 resection). For tumors that have invaded the sacrum, sacrectomy becomes necessary to achieve R0 resection. The objective of this study was to provide a descriptive multicenter account of resection for locally invasive colorectal carcinoma with sacral invasion, focusing on the association of tumor morphometry with surgical planning and perioperative outcomes. METHODS Demographic, comorbidity, clinical, tumor-specific, operative characteristic, and outcome data were collected on all patients who underwent resection of colorectal carcinoma with concurrent sacral resection between January 2005 and May 2022. Patients were grouped into those having undergone surgery for purely palliative intent, or those with resection with attempt at local control and dichotomized into level of osteotomy (either proximal or distal to the S2–3 level). RESULTS Twenty-two patients (median age 50.5 [IQR 43.3–60.0] years, 54.5% female) underwent sacrectomy for colorectal carcinoma. Operative records indicated intent for local control in 14 patients and palliative in the remaining 8 patients. Palliative surgical intent was based primarily on the presence of distant metastases. There was no significant difference in median local progression-free survival between patients undergoing osteotomy proximal to the S2–3 level and those undergoing osteotomy distal to the S2–3 level. CONCLUSIONS En bloc resection is believed to offer the best local control in patients with locally invasive colorectal carcinoma. The present descriptive series highlights outcomes of en bloc resection with partial or full sacrectomy in patients with tumors showing local extension into the sacrum. Complications are common, most often in the form of wound dehiscence or infection, and many patients require placement in a rehabilitation or intermediate-care facility upon discharge. However, for those with stage III (locally aggressive) disease, median OS exceeds 16 years, suggesting that such aggressive management with en bloc resection may be warranted in properly selected patients.

Study Design Retrospective Cohort. Objectives Craniovertebral instability can arise from various congenital or acquired conditions, but definitive management often requires craniocervical fusion. This study evaluates whether postoperative clivo-axial angle (CXA) can predict distal junctional failure in patients undergoing craniocervical fusion. While postoperative alignment of the head and cervical spine can be quantified via the CXA, it is unclear whether the CXA can predict distal junctional failure. Methods All patients undergoing craniocervical decompression and fusion (CCF) for craniovertebral instability between 2012 and 2023 at a single institution were identified. Patients experiencing adjacent segment disease (ASD) were identified and compared to those without said pathology based on CXA, Grabb-Oakes line (pBC2), and the presence of cervical kyphosis, cervical disc degeneration, or subluxation on pre- and postoperative imaging. Statistical analysis included Shapiro-Wilk tests for normality, followed by independent t-tests or Mann-Whitney U tests with FDR adjusted P values as appropriate, and univariable logistic regression. Results 71 patients were included, of whom ten (14.3%) developed distal junctional kyphosis and 3 (4.3%) developed cervical spondylolisthesis. The median postoperative CXA was significantly lower in non-ASD patients (144° [IQR: 140-148°] vs 158° [IQR: 153-162°]; P < .001) and logistic regression showed that each 10° degree increase in CXA was associated with a 6.7-fold higher odds of ASD. Conclusions We found craniocervical alignment, as assessed by CXA, independently predicted distal junctional disease in patients undergoing craniocervical fusion, possibly due to low preoperative CXA in these patients. Large increases in CXA may contribute to postoperative instrumentation failure.

Study Design Narrative Review. Objective The management of spinal tumors requires a multi-disciplinary approach including surgery, radiation, and systemic therapy. Surgical approaches typically require posterior segmental instrumentation to maintain long-term spinal stability. Carbon fiber reinforced pedicle screws (CFRP) are increasingly used in the oncologic setting due to reductions in both imaging artifacts and radiotherapy perturbations compared to titanium implants. We performed a review of the literature and highlight advantages and future areas of study for CFRP. Methods We performed a systematic review of the literature using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and identified 10 articles including 573 patients. Across all studies we reviewed patient demographics, tumor types treated, hardware-related features, complication rates, recurrence, survival, and follow-up. Results Across 10 studies, a total of 1371 screws placed. Surgical and non-surgical complications were reported in 18.3% of patients. Disease progression at the surgical site was detected in 7.3% of patients. There was no significant difference in clinical or hardware complications between CFRP or titanium implants. The most frequent complication attributable to implanted CFRP hardware included screw breakage in 2.4% and loosening in 1.7% of patients, respectively. Conclusion CFRP provide a unique tool in the setting of spinal oncology. With a safety profile comparable to titanium, we review the documented advantages of CFRP posterior implants compared to titanium, while also addressing their current limitations. Additionally, we highlight several areas of future research to identify the optimal patients who will achieve the greatest benefit of CFRP.

OBJECTIVE Intramedullary spinal cord tumors (IMSCTs) are rare tumors with heterogeneous presentations and natural histories that complicate their management. Standardized guidelines are lacking on when to surgically intervene and the appropriate aggressiveness of resection, especially given the risk of new neurological deficits following resection of infiltrative tumors. Here, the authors present the results of a modified Delphi method using input from surgeons experienced with IMSCT removal to construct a framework for the operative management of IMSCTs based on the clinical, radiographic, and tumor-specific characteristics. METHODS A modified Delphi technique was conducted using a group of 14 neurosurgeons experienced in IMSCT resection. Three rounds of written correspondence, surveys, and videoconferencing were carried out. Participants were queried about clinical and radiographic criteria used to determine operative candidacy and guide decision-making. Members then completed a final survey indicating their choice of observation or surgery, choice of resection strategy, and decision to perform duraplasty, in response to a set of patient- and tumor-specific characteristics. Consensus was defined as ≥ 80% agreement, while responses with 70%–79% agreement were defined as agreement. RESULTS Thirty-six total characteristics were assessed. There was consensus favoring surgical intervention for patients with new-onset myelopathy (86% agreement), chronic myelopathy (86%), or progression from mild to disabling numbness (86%), but disagreement for patients with mild numbness or chronic paraplegia. Age was not a determinant of operative candidacy except among frail patients, who were deemed more suitable for observation (93%). Well-circumscribed (93%) or posteriorly located tumors reaching the surface (86%) were consensus surgical lesions, and participants agreed that the presence of syringomyelia (71%) and peritumoral T2 signal change (79%) were favorable indications for surgery. There was consensus that complete loss of transcranial motor evoked potentials with a 50% decrease in the D-wave amplitude should halt further resection (93%). Preoperative symptoms seldom influenced choice of resection strategy, while a distinct cleavage plane (100%) or visible tumor-cord margins (100%) strongly favored gross-total resection. CONCLUSIONS The authors present a modified Delphi technique highlighting areas of consensus and agreement regarding surgical management of IMSCTs. Although not intended as a substitute for individual clinical decision-making, the results can help guide care of these patients. Additionally, areas of controversy meriting further investigation are highlighted.

BACKGROUND AND OBJECTIVES: Sacrectomy is often the treatment of choice to provide the greatest chance of progression-free and overall survival for patients with primary malignant bone tumors of the sacrum. After midsacrectomy, the stability of the sacropelvic interface is diminished, resulting in insufficiency fractures. Traditional stabilization involves lumbopelvic fixation but subjects normal mobile segments to fusion. The purpose of this study was to determine whether standalone intrapelvic fixation is a safe adjunct to midsacrectomy, avoiding both sacral insufficiency fractures and the morbidity of instrumenting into the mobile spine. METHODS: A retrospective study identified all patients who underwent resection of sacral tumors at 2 comprehensive cancer centers between June 2020 and July 2022. Demographic, tumor-specific, operative characteristics and outcome data were collected. The primary outcome was presence of sacral insufficiency fractures. A retrospective data set of patients undergoing midsacrectomy without hardware placement was collected as a control. RESULTS: Nine patients (5 male, 4 female), median age 59 years, underwent midsacrectomy with concomitant placement of standalone pelvic fixation. No patients developed insufficiency fractures during the 216 days of clinical and 207 days of radiographic follow-up. There were no adverse events attributable to the addition of standalone pelvic fixation. In our historical cohort of partial sacrectomies without stabilization, there were 4/25 patients (16%) with sacral insufficiency fractures. These fractures appeared between 0 and 5 months postoperatively. CONCLUSION: A novel standalone intrapelvic fixation after partial sacrectomy is a safe adjunct to prevent postoperative sacral insufficiency fractures in patients undergoing midsacrectomy for tumor. Such a technique may allow for long-term sacropelvic stability without sacrificing mobile lumbar segments.

Study Design. A cross-sectional study was performed using the National Institutes of Health All of Us survey database. Objective. The aim of this study was to assess socioeconomic and racial disparities in the perception of personal health, health literacy, and healthcare access among spine oncology patients. Summary of Background Data. Racial, ethnic, and socioeconomic disparities in health literacy and perception of health status have been described for many disease processes. However, few studies have assessed the prevalence of these disparities among spine oncology patients. Methods. Adult spine oncology patients, identified using ICD-9/10-CM codes, were categorized by race/ethnicity: White/Caucasian (WC), Black/African-American (BAA), and Non-White Hispanic (NWH). Demographics and socioeconomic status were assessed. Questionnaire responses regarding baseline health status, perception of health status, health literacy, and barriers to healthcare were compared. Results. Of the 1,175 patients identified, 207 (17.6%) were BAA, 267 (22.7%) were NWH, and 701 (59.7%) were WC. Socioeconomic status varied among cohorts, with WC patients reporting higher levels of education (P<0.001), annual income greater than $50K (P<0.001), and home ownership (P<0.001). BAA and NWH patients reported greater rates of 7-day “Severe fatigue” (P<0.001) and “10/10 pain” (P<0.001) and lower rates of “Completely” able to perform everyday activities (P<0.001). WC patients had a higher response rate for “Excellent/Very Good” regarding their own general health (P<0.001) and quality (P<0.001). The WC cohort had a significantly higher proportion of patients responding “Never” when assessing difficulty understanding (P<0.001) and needing assistance with health materials (P<0.001). BAA and NWH were significantly less likely to report feeling “Extremely” confident with medical forms (P<0.001). BAA and NWH had significantly higher response rates to feeling “Somewhat Worried” about healthcare costs (P<0.001) and with delaying medical care given “Can’t Afford Co-pay” (P<0.001). Conclusion. We identified disparities in perception of health status, literacy, and access among spine oncology patients. Level of Evidence. 4

Study Design Retrospective cohort study Objective The aim of this study was to determine the relative importance and predicative power of the Hospital Frailty Risk Score (HFRS) on unplanned 30-day readmission after surgical intervention for metastatic spinal column tumors. Methods All adult patients undergoing surgery for metastatic spinal column tumor were identified in the Nationwide Readmission Database from the years 2016 to 2018. Patients were categorized into 3 cohorts based on the criteria of the HFRS: Low(<5), Intermediate(5-14.9), and High(≥ 15). Random Forest (RF) classification was used to construct predictive models for 30-day patient readmission. Model performance was examined using the area under the receiver operating curve (AUC), and the Mean Decrease Gini (MDG) metric was used to quantify and rank features by relative importance. Results There were 4346 patients included. The proportion of patients who required any readmission were higher among the Intermediate and High frailty cohorts when compared to the Low frailty cohort ( Low:33.9% vs. Intermediate:39.3% vs. High:39.2%, P < .001). An RF classifier was trained to predict 30-day readmission on all features (AUC = .60) and architecturally equivalent model trained using only ten features with highest MDG (AUC = .59). Both models found frailty to have the highest importance in predicting risk of readmission. On multivariate regression analysis, Intermediate frailty [ OR:1.32, CI(1.06,1.64), P = .012] was found to be an independent predictor of unplanned 30-day readmission. Conclusion Our study utilizes machine learning approaches and predictive modeling to identify frailty as a significant risk-factor that contributes to unplanned 30-day readmission after spine surgery for metastatic spinal column metastases.