Akinduro, Oluwaseun O.

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.

Neurosurgical education is a continually developing field with an aim of training competent and compassionate surgeons who can care for the needs of their patients. The Mayo Clinic utilizes a unique mentorship model for neurosurgical training. In this paper, the authors detail the historical roots as well as the logistical and experiential characteristics of this teaching model. This model was first established in the late 1890s by the Mayo brothers and then adopted by the Mayo Clinic Department of Neurological Surgery at its inception in 1919. It has since been implemented enterprise-wide at the Minnesota, Florida, and Arizona residency programs. The mentorship model is focused on honing resident skills through individualized attention and guidance from an attending physician. Each resident is closely mentored by a consultant during a 2- or 3-month rotation, which allows for exposure to more complex cases early in their training. In this model, residents take ownership of their patients’ care, following them longitudinally during their hospital course with guided oversight from their mentors. During the chief year, residents have their own clinic, operating room (OR) schedule, and OR team and service nurse. In this model, chief residents conduct themselves more in the manner of an attending physician than a trainee but continue to have oversight from staff to provide a “safety net.” The longitudinal care of patients provided by the residents under the mentorship model is not only beneficial for the trainee and the hospital, but also has a positive impact on patient satisfaction and safety. The Mayo Clinic Mentorship Model is one of many educational models that has demonstrated itself to be an excellent approach for resident education.

Abstract INTRODUCTION Multiple meningiomas (MM) occurs in up to 18% of meningioma patients and progression data are scarce. The objective of this study is to explore the influence of number of lesions and clinical characteristics on progression-free survival (PFS) and time to a second intervention (TTSI) in patients with WHO grade 1 meningiomas. METHODS We retrospectively reviewed records of all adults diagnosed with a meningioma at our three main sites from January 2009 to May 2020. Progression was considered as time from diagnosis until radiographic progression of the originally resected meningioma. A secondary analysis was carried to evaluate the time from diagnosis to time of a second intervention. Univariable and multivariable analyses were conducted to assess whether number of lesions or any associated variables (age, sex, race, radiation, location, and extent of resection) had a significant impact on PFS and TTSI. RESULTS 838 patients were included. Log-rank test evaluating PFS and TTSI between single and multiple lesions showed significantly shorter progression for MM (p&lt; 0.001 and p&lt; 0.001, respectively). Multivariable Cox regression showed significantly inferior PFS on MM vs. single lesion (HR 2.262 [CI 95%, 1.392-3.677], p=0.001) and a significantly inferior TTSI for patients with MM vs. single meningioma (HR 2.377 [CI 95%, 1.617 – 3.494], p=0.001). When input as a continuous variable, PFS was significantly inferior for each additional meningioma (HR 1.350 [CI 95% 1.074-1.698], p=0.010) and TTSI is significantly inferior as well (HR 1.428 [CI 95% 1.189 – 1.716], p&lt; 0.001). African-Americans had an inferior PFS when compared to Non-Hispanic White patients (HR 3.472 [CI 95% 1.083-11.129], p=0.036). CONCLUSION The PFS of meningiomas is influenced by the number of lesions present. Patients with MM are more prone to undergo a second intervention for progressive disease. Hence, a closer follow-up may be warranted in patients who present with multiple lesions.

OBJECTIVE Recent studies have proposed resection of the T2 FLAIR hyperintensity beyond the T1 contrast enhancement (supramarginal resection [SMR]) for IDH–wild-type glioblastoma (GBM) to further improve patients’ overall survival (OS). GBMs have significant variability in tumor cell density, distribution, and infiltration. Advanced mathematical models based on patient-specific radiographic features have provided new insights into GBM growth kinetics on two important parameters of tumor aggressiveness: proliferation rate (ρ) and diffusion rate (D). The aim of this study was to investigate OS of patients with IDH–wild-type GBM who underwent SMR based on a mathematical model of cell distribution and infiltration profile (tumor invasiveness profile). METHODS Volumetric measurements were obtained from the selected regions of interest from pre- and postoperative MRI studies of included patients. The tumor invasiveness profile (proliferation/diffusion [ρ/D] ratio) was calculated using the following formula: ρ/D ratio = (4π/3) 2/3 × (6.106/[V T2 1/1 − V T1 1/1 ]) 2 , where V T2 and V T1 are the preoperative FLAIR and contrast-enhancing volumes, respectively. Patients were split into subgroups based on their tumor invasiveness profiles. In this analysis, tumors were classified as nodular, moderately diffuse, or highly diffuse. RESULTS A total of 101 patients were included. Tumors were classified as nodular (n = 34), moderately diffuse (n = 34), and highly diffuse (n = 33). On multivariate analysis, increasing SMR had a significant positive correlation with OS for moderately and highly diffuse tumors (HR 0.99, 95% CI 0.98–0.99; p = 0.02; and HR 0.98, 95% CI 0.96–0.99; p = 0.04, respectively). On threshold analysis, OS benefit was seen with SMR from 10% to 29%, 10% to 59%, and 30% to 90%, for nodular, moderately diffuse, and highly diffuse, respectively. CONCLUSIONS The impact of SMR on OS for patients with IDH–wild-type GBM is influenced by the degree of tumor invasiveness. The authors’ results show that increasing SMR is associated with increased OS in patients with moderate and highly diffuse IDH–wild-type GBMs. When grouping SMR into 10% intervals, this benefit was seen for all tumor subgroups, although for nodular tumors, the maximum beneficial SMR percentage was considerably lower than in moderate and highly diffuse tumors.

Abstract IntroductionRadiotherapy is considered standard of care for adjuvant peri-operative treatment of many spinal tumors, including those with instrumented fusion. Unfortunately, radiation treatment has been linked to increased risk of pseudoarthrosis. Newerfocused radiotherapy strategies with enhanced conformalitycould offer improved fusion rates for these patients, but this has not been confirmed.MethodsWe performed a retrospective analysis of patients at three tertiary care academic institutions withprimary and secondary spinal malignancies that underwent resection, instrumented fusion, and peri-operative radiotherapy. Two board certified neuro-radiologists used theLenke fusion score to grade fusion status at6 and 12-months after surgery. Secondary outcomes includedclinical pseudoarthrosis, wound complications, and the effect of radiation timing, radiobiological dose delivered, the use of photons versus protons, tumor type, tumor location,and use of autograft on fusion outcomes.ResultsAfter reviewof 1252 spinal tumor patients, there were 60 patients with at least 6 months follow-up that were included in our analyses. Twenty-five of these patients received focused radiotherapy,20 patients received conventional radiotherapy, and 15 patients were treated with protons. There was no significant difference between the groups for covariates such assmoking status,obesity, diabetes, intraoperative use of autograft, and use of peri-operative chemotherapy. There was a significantly higher rate of fusion for patients treated with focused radiotherapy compared to those treated with conventional radiotherapy at 6-months (64.0% versus 30.0%, Odds ratio: 4.15, p=0.036) and 12-months (80.0% versus 42.1%, OR: 5.50, p=0.022). There was a significantly higher rate of clinical pseudoarthrosis in the conventional radiotherapy cohortcompared to patients in the focused radiotherapy cohort (19.1% versus 0%,p=0.037). There was no difference in fusion outcomes for any of the secondary outcomes except for use of autograft. The use ofintra-operative autograft was associated with an improved fusion at 12-months (66.7% versus 37.5%, OR: 3.33, p=0.043). ConclusionFocused radiotherapy may be associated withan improved rate of fusion and clinical pseudoarthrosis when compared to conventional radiation delivery strategiesin patients with spinal tumors.Use of autograft at the time of surgery may be associated with improved 12-month fusion rates.Further large-scale prospective and randomized controlled studies are needed to better stratify the effects of radiation delivery modality in these patients.

OBJECTIVE High-grade spinal glioma (HGSG) is a rare but aggressive tumor that occurs in both adults and children. Histone H3 K27M mutation correlates with poor prognosis in children with diffuse midline glioma. However, the role of H3 K27M mutation in the prognosis of adults with HGSG remains unclear owing to the rarity of this mutation, conflicting reports, and the absence of multicenter studies on this topic. METHODS The authors studied a cohort of 30 adult patients with diffuse HGSG who underwent histological confirmation of diagnosis, surgical intervention, and treatment between January 2000 and July 2020 at six tertiary academic centers. The primary outcome was the effect of H3 K27M mutation status on progression-free survival (PFS) and overall survival (OS). RESULTS Thirty patients (18 males and 12 females) with a median (range) age of 50.5 (19–76) years were included in the analysis. Eighteen patients had H3 K27M mutation–positive tumors, and 12 had H3 K27M mutation–negative tumors. The median (interquartile range) PFS was 3 (10) months, and the median (interquartile range) OS was 9 (23) months. The factors associated with increased survival were treatment with concurrent chemotherapy/radiation (p = 0.006 for PFS, and p ≤ 0.001 for OS) and American Spinal Injury Association grade C or better at presentation (p = 0.043 for PFS, and p < 0.001 for OS). There were no significant differences in outcomes based on tumor location, extent of resection, sex, or H3 K27M mutation status. Analysis restricted to HGSG containing necrosis and/or microvascular proliferation (WHO grade IV histological features) revealed increased OS for patients with H3 K27M mutation–positive tumors (p = 0.017). CONCLUSIONS Although H3 K27M mutant–positive HGSG was associated with poor outcomes in adult patients, the outcomes of patients with H3 K27M mutant–positive HGSG were somewhat more favorable compared with those of their H3 K27M mutant–negative HGSG counterparts. Further preclinical animal studies and larger clinical studies are needed to further understand the age-dependent effects of H3 K27M mutation.

Abstract Background En bloc spondylectomy is the gold standard for surgical resection of sacral chordomas (CHO), but the effect of extent of resection on recurrence and survival in patients with CHO of the cervical spine remains elusive. Methods MEDLINE, Embase, Scopus, and Cochrane were systematically reviewed. Patients with cervical CHO treated at three tertiary-care academic institutions were reviewed for inclusion. We performed an individual participant data meta-analysis to assess the overall survival (OS) and progression free survival (PFS) after en bloc-gross total resection (GTR) and intralesional-GTR compared to subtotal resection (STR). We then performed an intention-to-treat analysis including all patients with attempted en bloc resection in the en bloc group, regardless of the surgical margins. Results There was a total of 13 series including 161 patients with cervical CHO, including our current series of 22 patients. GTR (en bloc-GTR + intralesional-GTR) was associated with a significant decrease in the risk of local progression (pooled hazard ratio (PHR) = 0.22; 95% CI = 0.08–0.59; p = 0.003) and risk of death (PHR = 0.31; 95%; CI:0.12–0.83; p = 0.020). A meta-regression analyses determined that intralesional-GTR improved PFS (PHR = 0.35; 95%CI = 0.16–0.76; p = 0.009) as well as OS (PHR = 0.25; 95%CI = 0.08–0.79; p = 0.019) when compared to STR. En bloc-GTR was associated with a significant reduction in the risk of local progression (PHR = 0.06; 95%CI = 0.01–0.77; p = 0.030), but not a decreased OS (PHR = 0.50; 95% CI = 0.19–1.27; p = 0.145). Our intention-to-treat analyses revealed a near significant improvement in OS for the en bloc group (PHR: 0.15; 95%CI:0.02–1.22; p = 0.054), and nearly identical improvement in PFS. Radiation data was not available for the studies included in the meta-analysis. Conclusion This is the first and only meta-analysis of patients with cervical CHO. We found that both en bloc-GTR and intralesional-GTR resulted in improved local tumor control when compared to STR.

Abstract We describe the clinical case of a 62-year-old man with an atypical grade II meningioma, invading bone and scalp, and present a step-by-step video description of a modified technique for cranioplasty and scalp reconstruction with latissimus dorsi flap. By using this technique, we aim to minimize the space between the dura and the flap, which would decrease the risk of fluid collections and infections.

Abstract BACKGROUND There is a paucity of literature regarding treatment options for extracranial pseudoaneurysms of the internal carotid artery (ICA). To date, Pipeline Embolization Device (PED; Medtronic Inc) use for the treatment of extracranial pseudoaneurysms of the ICA has only been reported from single-center case series. OBJECTIVE To evaluate the safety and efficacy of PED for the treatment of extracranial ICA pseudoaneurysms. METHODS This is a multicenter retrospective study involving 6 high-volume tertiary academic institutions in the United States. We analyzed patients with extracranial ICA pseudoaneurysms treated with PED between January 1, 2011, and January 1, 2019. Clinical assessment was performed pre- and postintervention using the modified Rankin Scale (mRS) and National Institution of Health Stroke Scale (NIHSS) at a minimum of 4-mo follow-up. RESULTS A total of 28 pseudoaneurysms with a mean diameter of 17.7 mm (range: 4.1-52.5 mm) were treated with PED in 24 patients at 6 participating centers. The mean age was 52.1 yr (17-73) ± 14.3 with 14 females and 10 males. At a mean of 21-mo (range 4-66 mo) follow-up, complete occlusion was achieved in 89% (n = 25/28), with near-complete occlusion (>90% occlusion) in the remainder. There were no periprocedural complications. Postprocedure NIHSS was 0 in 88% (n = 21/24) and 1 in 12% (n = 3/24) of patients, and mRS was 0 in 83% (n = 20/24) and 1 in 17% (n = 4/24) of patients. CONCLUSION The treatment of extracranial ICA pseudoaneurysms with PED is safe and effective in selected patients. Randomized controlled trials and prospective cohort studies are needed to establish the role of flow diversion for ICA pseudoaneurysms.

Abstract We describe the operative approach and management for thoracic metastatic disease in a 78-yr-old man with worsening mechanical lower back and left-sided thoracic radicular pain. Imaging of the thoracic spine revealed an osteolytic T11 mass with destruction of the left T11 pedicle and transverse process. Biopsy confirmed spinal metastasis from the liver. Preoperative angiogram was completed for localization of the artery of Adamkewicz and microparticle embolization of the left T11 intercostal artery. Surgical resection was supplemented with electrophysiological monitoring and neuronavigation. The corpectomy was approached by resecting the medial aspect of the rib, transverse process, and pedicle, which were all invaded with tumor. The left T11 nerve root was isolated and sacrificed to allow for placement of the expandable corpectomy cage and also resulted in sustained relief of the patient's radicular pain. The patient recovered from surgery well, with postoperative improvement of his pain. This case highlights the complex technical nuances of this procedure, and the importance of a thorough preoperative evaluation, including angiography, as proper identification of the artery of Adamkewitz can prevent severe neurological deficit from a spinal cord stroke. The patient consented to the procedure.