Ehresman, Jeff

OBJECTIVE Infuse bone graft is a widely used osteoinductive adjuvant; however, the simple collagen sponge scaffold used in the implant has minimal inherent osteoinductive properties and poorly controls the delivery of the adsorbed recombinant human bone morphogenetic protein–2 (rhBMP-2). In this study, the authors sought to create a novel bone graft substitute material that overcomes the limitations of Infuse and compare the ability of this material with that of Infuse to facilitate union following spine surgery in a clinically translatable rat model of spinal fusion. METHODS The authors created a polydopamine (PDA)–infused, porous, homogeneously dispersed solid mixture of extracellular matrix and calcium phosphates (BioMim-PDA) and then compared the efficacy of this material directly with Infuse in the setting of different concentrations of rhBMP-2 using a rat model of spinal fusion. Sixty male Sprague Dawley rats were randomly assigned to each of six equal groups: 1) collagen + 0.2 µg rhBMP-2/side, 2) BioMim-PDA + 0.2 µg rhBMP-2/side, 3) collagen + 2.0 µg rhBMP-2/side, 4) BioMim-PDA + 2.0 μg rhBMP-2/side, 5) collagen + 20 µg rhBMP-2/side, and 6) BioMim-PDA + 20 µg rhBMP-2/side. All animals underwent posterolateral intertransverse process fusion at L4–5 using the assigned bone graft. Animals were euthanized 8 weeks postoperatively, and their lumbar spines were analyzed via microcomputed tomography (µCT) and histology. Spinal fusion was defined as continuous bridging bone bilaterally across the fusion site evaluated via µCT. RESULTS The fusion rate was 100% in all groups except group 1 (70%) and group 4 (90%). Use of BioMim-PDA with 0.2 µg rhBMP-2 led to significantly greater results for bone volume (BV), percentage BV, and trabecular number, as well as significantly smaller trabecular separation, compared with the use of the collagen sponge with 2.0 µg rhBMP-2. The same results were observed when the use of BioMim-PDA with 2.0 µg rhBMP-2 was compared with the use of the collagen sponge with 20 µg rhBMP-2. CONCLUSIONS Implantation of rhBMP-2–adsorbed BioMim-PDA scaffolds resulted in BV and bone quality superior to that afforded by treatment with rhBMP-2 concentrations 10-fold higher implanted on a conventional collagen sponge. Using BioMim-PDA (vs a collagen sponge) for rhBMP-2 delivery could significantly lower the amount of rhBMP-2 required for successful bone grafting clinically, improving device safety and decreasing costs.

OBJECTIVE Previous studies have suggested the possibility of racial disparities in surgical outcomes for patients undergoing spine surgery, although this has not been thoroughly investigated in those with spinal metastases. Given the increasing prevalence of spinal metastases requiring intervention, knowledge about potential discrepancies in outcomes would benefit overall patient care. The objective in the present study was to investigate whether race was an independent predictor of postoperative complications, nonroutine discharge, and prolonged length of stay (LOS) after surgery for spinal metastasis. METHODS The authors retrospectively examined patients at a single comprehensive cancer center who had undergone surgery for spinal metastasis between April 2013 and April 2020. Demographic information, primary pathology, preoperative clinical characteristics, and operative outcomes were collected. Factors achieving p values < 0.15 on univariate regression were entered into a stepwise multivariable logistic regression to generate predictive models. Nonroutine discharge was defined as a nonhome discharge destination and prolonged LOS was defined as LOS greater than the 75th percentile for the entire cohort. RESULTS Three hundred twenty-eight patients who had undergone 348 operations were included: 240 (69.0%) White and 108 (31.0%) Black. On univariable analysis, cohorts significantly differed in age (p = 0.02), marital status (p < 0.001), insurance status (p = 0.03), income quartile (p = 0.02), primary tumor type (p = 0.04), and preoperative Karnofsky Performance Scale (KPS) score (p < 0.001). On multivariable analysis, race was an independent predictor for nonroutine discharge: Black patients had significantly higher odds of nonroutine discharge than White patients (adjusted odds ratio [AOR] 2.24, 95% confidence interval [CI] 1.28–3.92, p = 0.005). Older age (AOR 1.06 per year, 95% CI 1.03–1.09, p < 0.001), preoperative KPS score ≤ 70 (AOR 3.30, 95% CI 1.93–5.65, p < 0.001), preoperative Frankel grade A–C (AOR 3.48, 95% CI 1.17–10.3, p = 0.02), insurance status (p = 0.005), being unmarried (AOR 0.58, 95% CI 0.35–0.97, p = 0.04), number of levels (AOR 1.17 per level, 95% CI 1.05–1.31, p = 0.004), and thoracic involvement (AOR 1.71, 95% CI 1.02–2.88, p = 0.04) were also predictive of nonroutine discharge. However, race was not independently predictive of postoperative complications or prolonged LOS. Higher Charlson Comorbidity Index (AOR 1.22 per point, 95% CI 1.04–1.43, p = 0.01), low preoperative KPS score (AOR 1.84, 95% CI 1.16–2.92, p = 0.01), and number of levels (AOR 1.15 per level, 95% CI 1.05–1.27, p = 0.004) were predictive of complications, while insurance status (p = 0.05), income quartile (p = 0.01), low preoperative KPS score (AOR 1.64, 95% CI 1.03–2.72, p = 0.05), and number of levels (AOR 1.16 per level, 95% CI 1.05–1.30, p = 0.004) were predictive of prolonged LOS. CONCLUSIONS Race, insurance status, age, baseline functional status, and marital status were all independently associated with nonroutine discharge. This suggests that a combination of socioeconomic factors and functional status, rather than medical comorbidities, may best predict postdischarge disposition in patients treated for spinal metastases. Further investigation in a prospective cohort is merited.

OBJECTIVE The extent of resection has been shown to improve outcomes in patients with meningiomas. However, resection can be complicated by constraining local anatomy, leading to subtotal resections. An understanding of the natural history of residual tumors is necessary to better guide postsurgical management and minimize recurrence. This study seeks to identify predictors of recurrence and high growth rate following subtotal resection of intracranial meningiomas. METHODS Adult patients who underwent primary surgical resection of a WHO grade I meningioma at a tertiary care institution from 2007–2017 were retrospectively reviewed. Volumetric tumor measurements were made on patients with subtotal resections. Stepwise multivariate proportional hazards regression analyses were performed to identify factors associated with time to recurrence, as well as stepwise multivariate regression analyses to assess for factors associated with high postoperative growth rate. RESULTS Of the 141 patients (18%) who underwent radiographic subtotal resection of an intracranial meningioma during the reviewed period, 74 (52%) suffered a recurrence, in which the median (interquartile range, IQR) time to recurrence was 14 (IQR 6–34) months. Among those tumors subtotally resected, the median pre- and postoperative tumor volumes were 17.19 cm 3 (IQR 7.47–38.43 cm 3 ) and 2.31 cm 3 (IQR 0.98–5.16 cm 3 ), which corresponded to a percentage resection of 82% (IQR 68%–93%). Postoperatively, the median growth rate was 0.09 cm 3 /year (IQR 0–1.39 cm 3 /year). Factors associated with recurrence in multivariate analysis included preoperative tumor volume (hazard ratio [HR] 1.008,95% confidence interval [CI] 1.002–1.013, p = 0.008), falcine location (HR 2.215, 95% CI 1.179–4.161, p = 0.021), tentorial location (HR 2.410, 95% CI 1.203–4.829, p = 0.024), and African American race (HR 1.811, 95% CI 1.042–3.146, p = 0.044). Residual volume (RV) was associated with high absolute annual growth rate (odds ratio [OR] 1.175, 95% CI 1.078–1.280, p < 0.0001), with the maximum RV benefit at < 5 cm 3 (OR 4.056, 95% CI 1.675–9.822, p = 0.002). CONCLUSIONS By identifying predictors of recurrence and growth rate, this study helps identify potential patients with a high chance of recurrence following subtotal resection, which are those with large preoperative tumor volume, falcine location, tentorial location, and African American race. Higher RVs were associated with tumors with higher postoperative growth rates. Recurrences typically occurred 14 months after surgery.

Object Meningiomas occur in various intracranial locations. Each location is associated with a unique set of surgical nuances and risk profiles. The incidence and risk factors that predispose patients to certain deficits based on tumor locations are unclear. This study aimed to determine which preoperative factors increase the risk of patients having new deficits after surgery based on tumor location for patients undergoing intracranial meningioma surgery. Methods Adult patients who underwent primary, nonbiopsy resection of a meningioma at a tertiary care institution between 2007 and 2015 were retrospectively reviewed. Stepwise multivariate logistic regression analyses were used to identify associations with postoperative deficits based on tumor location. Results Postoperatively, from the 761 included patients, there were 39 motor deficits (5.1%), 23 vision deficits (3.0%), 19 language deficits (2.5%), 27 seizures (3.5%), and 26 cognitive deficits (3.4%). The factors independently associated with any postoperative deficits were preoperative radiation (hazard ratio [HR] [95% confidence interval, CI] 3.000 [1.346–6.338], p = 0.008), cerebellopontine angle tumors (HR [95% CI] 2.126 [1.094–3.947], p = 0.03), Simpson grade 4 resections (HR [95% CI] 2.000 [1.271–3.127], p = 0.003), preoperative motor deficits (HR [95% CI] 1.738 [1.005–2.923], p = 0.048), preoperative cognitive deficits (HR [95% CI] 2.033 [1.144–3.504], p = 0.02), and perioperative pulmonary embolisms (HR [95% CI] 11.741 [2.803–59.314], p = 0.0009). Conclusion Consideration of the factors associated with postoperative deficits in this study may help guide treatment strategies for patients with meningiomas.