OBJECTIVE

Improper embryological development of the clivus, a bony structure that comprises part of the skull base, can lead to a clival canal defect. Previously thought to be a benign condition, clival canals have been reported to be associated with meningitis and meningoceles. In this review, the authors sought to present an unpublished case of a patient with a clival canal defect associated with meningitis and to evaluate all other reported cases.

METHODS

In October 2020, a search of PubMed, Web of Science, and Scopus was conducted to identify all cases of clival canals reported from January 1, 1980, through October 31, 2020.

RESULTS

Including the case presented herein, 13 cases of clival canals, 11 in children (84.6%) and 2 in adults (15.4%), have been identified. Of the pediatric patients, 5 (45.5%) had an associated meningocele, and 8 (72.7%) had meningitis. Nine of the 13 patients (69.2%) had defects that were treated surgically, 5 (38.5%) by a transnasal approach and 4 (30.8%) by a transoral approach. Two patients (15.4%) were treated with drainage and antibiotics, 1 patient (7.7%) was treated solely with antibiotics, and 1 patient (7.7%) was not treated. In the literature review, 8 reports of clival canals were found to be associated with meningitis, further contributing to the notion that the clival canal may be an overlooked source of recurrent infection. In several of these cases, surgical repair of the lesion was curative, thus preventing continued episodes of meningitis.

CONCLUSIONS

When a patient has recurrent meningitis with no clear cause, taking a closer look at clival anatomy is recommended. In addition, if a clival canal defect has been identified, surgical repair should be considered a safe and effective primary treatment option.

OBJECTIVE

Despite improvements in surgical techniques and instruments, high rates of rod fracture following a long spinal fusion in the treatment of adult spinal deformity (ASD) remain a concern. Thus, an improved understanding of rod fracture may be valuable for better surgical planning. The authors aimed to investigate mechanical stress on posterior rods in lumbopelvic fixation for the treatment of ASD.

METHODS

Synthetic lumbopelvic bone models were instrumented with intervertebral cages, pedicle screws, S2-alar-iliac screws, and rods. The construct was then placed in a testing device, and compressive loads were applied. Subsequently, the strain on the rods was measured using strain gauges on the dorsal aspect of each rod.

RESULTS

When the models were instrumented using titanium alloy rods at 30° lumbar lordosis and with lateral interbody fusion cages, posterior rod strain was highest at the lowest segment (L5–S1) and significantly higher than that at the upper segment (L2–3) (p = 0.002). Changing the rod contour from 30° to 50° caused a 36% increase in strain at L5–S1 (p = 0.009). Changing the rod material from titanium alloy to cobalt-chromium caused a 140% increase in strain at L2–3 (p = 0.009) and a 28% decrease in strain at L5–S1 (p = 0.016). The rod strain at L5–S1 using a flat bender for contouring was 23% less than that obtained using a French bender (p = 0.016).

CONCLUSIONS

In lumbopelvic fixation in which currently available surgical techniques for ASD are used, the posterior rod strain was highest at the lumbosacral junction, and depended on the contour and material of the rods.

OBJECTIVE

Paraspinal ganglioneuromas are rare tumors that arise from neural crest tissue and can cause morbidity via compression of adjacent organs and neurovascular structures. The authors investigated a case series of these tumors treated at their institution to determine clinical outcomes following resection.

METHODS

A retrospective review of a prospectively collected cohort of consecutive, pathology-confirmed, surgically treated paraspinal ganglioneuromas from 2001 to 2019 was performed at a tertiary cancer center.

RESULTS

Fifteen cases of paraspinal ganglioneuroma were identified: 47% were female and the median age at the time of surgery was 30 years (range 10–67 years). Resected tumors included 9 thoracic, 1 lumbar, and 5 sacral, with an average maximum tumor dimension of 6.8 cm (range 1–13.5 cm). Two patients had treated neuroblastomas that matured into ganglioneuromas. One patient had a secretory tumor causing systemic symptoms. Surgical approaches were anterior (n = 11), posterior (n = 2), or combined (n = 2). Seven (47%) and 5 (33%) patients underwent gross-total resection (GTR) or subtotal resection with minimal residual tumor, respectively. The complication rate was 20%, with no permanent neurological deficits or deaths. No patient had evidence of tumor recurrence or progression after a median follow-up of 68 months.

CONCLUSIONS

Surgical approaches and extent of resection for paraspinal ganglioneuromas must be heavily weighed against the advantages of aggressive debulking and decompression given the complication risk of these procedures. GTR can be curative, but even patients without complete tumor removal can show evidence of excellent long-term local control and clinical outcomes.

OBJECTIVE

Treatment outcomes following initial transsphenoidal surgery (TSS) for acromegaly are erratic. Identifying outcome patterns can assist in informing patients about possible treatment outcomes and planning for individualized adjuvant treatments in advance. In this study, the authors aimed to investigate the immediate and long-term endocrine remission rates following initial TSS for acromegaly, identify clinical determinants of treatment outcomes, and explore outcome patterns during a long-term follow-up and the pattern-specific patient features.

METHODS

This prospective, single-center, longitudinal cohort study enrolled patients with acromegaly who underwent TSS in the period from 2015 to 2018 at the authors’ institution. Immediate remission, assessed on the 2nd postoperative morning, and long-term remission, assessed at least 18 months after TSS, were evaluated according to the strict 2010 consensus criteria (random growth hormone [GH] < 1 ng/ml or GH nadir < 0.4 ng/ml after oral glucose tolerance test, and age- and sex-normalized insulin-like growth factor 1). Univariate and bivariate regression analyses were used to identify determinants of remission.

RESULTS

A total of 659 patients with acromegaly (average age 42 years, 44% males) underwent TSS for pituitary adenomas (macroadenomas, 85%; invasive tumors, 35%) and were followed up during a median of 51 months. Immediate and long-term remission rates after initial TSS were 37% and 69%, respectively. Older age at diagnosis (OR 1.7), male sex (OR 1.6), smaller tumors (OR 2.0), noninvasive tumors (OR 4.8), and tumors positive for follicle-stimulating hormone/luteinizing hormone (OR 1.5) were predictors of immediate surgical remission. In addition to the above predictors, lower preoperative GH (OR 2.4), absence of preoperative central hypothyroidism (OR 2.6), and endoscopic TSS (OR 10.6) were predictors of long-term remission. Regression analyses revealed that endoscopic TSS (OR 2.8, 95% CI 1.524–5.291, p = 0.001), absence of cavernous sinus invasion (OR 4.1, 95% CI 2.522–6.613, p < 0.001), older age (OR 1.03, 95% CI 1.006–1.048, p = 0.013), and male sex (OR 2.0, 95% CI 1.224–3.247, p = 0.006) were independent determinants of long-term remission. Five outcome patterns were identified based on the changes in hormonal results during follow-up, including continuous remission (34%), refractory acromegaly (28%), delayed remission (21%), remission after adjuvant therapy (14%), and recurrence after initial remission (3%). The clinical characteristics of each subgroup were identified.

CONCLUSIONS

Cavernous sinus invasion, age at diagnosis, and sex are the best determinants of immediate and long-term remission after initial TSS for acromegaly. Endoscopic TSS predicts a higher long-term remission rate than that with microscopic TSS. The authors identified five outcome patterns in acromegaly and group-specific patient characteristics for clinical decision-making.

OBJECTIVE

Prognostication of glioblastoma survival has become more refined due to the molecular reclassification of these tumors into isocitrate dehydrogenase (IDH) wild-type and IDH mutant. Since this molecular stratification, however, robust clinical prediction models relevant to the entire IDH wild-type glioblastoma patient population are lacking. This study aimed to provide an updated model that predicts individual survival prognosis in patients with IDH wild-type glioblastoma.

METHODS

Databases from Germany and the Netherlands provided data on 1036 newly diagnosed glioblastoma patients treated between 2012 and 2018. A clinical prediction model for all-cause mortality was developed with Cox proportional hazards regression. This model included recent glioblastoma-associated molecular markers in addition to well-known classic prognostic variables, which were updated and refined with additional categories. Model performance was evaluated according to calibration (using calibration plots and calibration slope) and discrimination (using a C-statistic) in a cross-validation procedure by country to assess external validity.

RESULTS

The German and Dutch patient cohorts consisted of 710 and 326 patients, respectively, of whom 511 (72%) and 308 (95%) had died. Three models were developed, each with increasing complexity. The final model considering age, sex, preoperative Karnofsky Performance Status, extent of resection, O⁶-methylguanine DNA methyltransferase (MGMT) promoter methylation status, and adjuvant therapeutic regimen showed an optimism-corrected C-statistic of 0.73 (95% confidence interval 0.71–0.75). Cross-validation between the national cohorts yielded comparable results.

CONCLUSIONS

This prediction model reliably predicts individual survival prognosis in patients with newly diagnosed IDH wild-type glioblastoma, although additional validation, especially for long-term survival, may be desired. The nomogram and web application of this model may support shared decision-making if used properly.

OBJECTIVE

This study attempts to use neurosurgical workforce distribution to uncover the social determinants of health that are associated with disparate access to neurosurgical care.

METHODS

Data were compiled from public sources and aggregated at the county level. Socioeconomic data were provided by the Brookings Institute. Racial and ethnicity data were gathered from the Centers for Disease Control and Prevention Wide-ranging Online Data for Epidemiologic Research. Physician density was retrieved from the Health Resources and Services Administration Area Health Resources Files. Catchment areas were constructed based on the 628 counties with neurosurgical coverage, with counties lacking neurosurgical coverage being integrated with the nearest covered county based on distances from the National Bureau of Economic Research’s County Distance Database. Catchment areas form a mutually exclusive and collectively exhaustive breakdown of the entire US population and licensed neurosurgeons.

Socioeconomic factors, race, and ethnicity were chosen as independent variables for analysis. Characteristics for each catchment area were calculated as the population-weighted average across all contained counties. Linear regression analysis modeled two outcomes of interest: neurosurgeon density per capita and average distance to neurosurgical care. Coefficient estimates (CEs) and 95% confidence intervals were calculated and scaled by 1 SD to allow for comparison between variables.

RESULTS

Catchment areas with higher poverty (CE = 0.64, 95% CI 0.34–0.93) and higher prime age employment (CE = 0.58, 95% CI 0.40–0.76) were significantly associated with greater neurosurgeon density. Among categories of race and ethnicity, catchment areas with higher proportions of Black residents (CE = 0.21, 95% CI 0.06–0.35) were associated with greater neurosurgeon density. Meanwhile, catchment areas with higher proportions of Hispanic residents displayed lower neurosurgeon density (CE = −0.17, 95% CI −0.30 to −0.03). Residents of catchment areas with higher housing vacancy rates (CE = 2.37, 95% CI 1.31–3.43), higher proportions of Native American residents (CE = 4.97, 95% CI 3.99–5.95), and higher proportions of Hispanic residents (CE = 2.31, 95% CI 1.26–3.37) must travel farther, on average, to receive neurosurgical care, whereas people living in areas with a lower income (CE = −2.28, 95% CI −4.48 to −0.09) or higher proportion of Black residents (CE = −3.81, 95% CI −4.93 to −2.68) travel a shorter distance.

CONCLUSIONS

Multiple factors demonstrate a significant correlation with neurosurgical workforce distribution in the US, most notably with Hispanic and Native American populations being associated with greater distances to care. Additionally, higher proportions of Hispanic residents correlated with fewer neurosurgeons per capita. These findings highlight the interwoven associations among socioeconomics, race, ethnicity, and access to neurosurgical care nationwide.

OBJECTIVE

Giant pituitary adenomas (PAs), defined as 4 cm or greater at their maximum diameter, are commonly treated with neurosurgical intervention as the first-line therapy. However, existing studies are from high-volume institutions whose outcomes may not be representative of many cancer centers. In the present study, the authors use a large cancer registry to evaluate demographics, national treatment trends, and outcomes by facility volume to address knowledge gaps for this uncommon tumor.

METHODS

The National Cancer Database was queried for adult patients with PAs who had undergone resection from 2004 to 2016. Univariate and multivariate logistic regression modeling was used to evaluate the prognostic impact of covariates on short-term outcomes including 30-day readmission (30R), 30-day mortality (30M), 90-day mortality (90M), and prolonged length of inpatient hospital stay (LOS). Propensity score matching was used for validation.

RESULTS

Among the 39,030 patients who met the study inclusion criteria, 3696 giant PAs were identified. These tumors had higher rates of subtotal resection (55% vs 24%, p < 0.001), adjunctive radiotherapy (15% vs 5%, p < 0.001), and hormonal therapy (8% vs 4%, p < 0.001) than nongiant PAs. The giant PAs also had worse 30M (0.6% vs 3.1%, p < 0.001), 90M (1.0% vs 5.0%, p < 0.001), 30R (4.0% vs 6.3%, p < 0.001), and LOS (22.2% vs 42.1%, p < 0.001). On multivariate analysis for giant PA, decreased tumor size, younger age, race other than African American, lower comorbidity score, and high-volume facility (HVF; defined as ≥ 2.5 giant PA cases per year) were statistically significant predictors of favorable outcomes. Specifically, 30M, 90M, 30R, and LOS were decreased by 50%, 43%, 55%, and 32%, respectively, when giant PAs were treated at HVFs (each p < 0.05). HVFs more often used the endoscopic approach (71% vs 46%, p < 0.001) and less adjuvant radiotherapy (11% vs 16%, p < 0.001). Propensity score matching validated 30M, 30R, and LOS outcome differences in a cohort of 1056 patients.

CONCLUSIONS

This study provides evidence of superior outcomes when giant PAs are treated at HVFs. These results likely reflect the relation between physician experience and outcomes for these uncommon tumors, which suggests the need for institutional collaboration as a potential goal in their surgical management.

OBJECTIVE

The authors sought to determine if a consensus could be reached regarding the effectiveness of endotracheal tube cuff pressure (ETTCP) reduction after retractor placement in reducing postoperative laryngeal dysfunction after anterior cervical fusion surgery.

METHODS

A literature search of MEDLINE (PubMed), EMBASE, Cochrane Central, Google Scholar, and Scopus databases was performed. Quantitative analysis was performed on data from articles comparing groups of patients with either reduced or unadjusted ETTCP after retractor placement in the context of anterior cervical surgery. The incidence and severity of postoperative recurrent laryngeal nerve palsy (RLNP), dysphagia, and dysphonia were compared at several postsurgical time points, ranging from 24 hours to 3 months. Heterogeneity was assessed using the chi-square test, I statistics, and inverted funnel plots. A random-effects model was used to provide a conservative estimate of the level of effect.

RESULTS

Nine studies (7 randomized, 1 prospective, and 1 retrospective) were included in the analysis. A total of 1671 patients were included (1073 [64.2%] in the reduced ETTCP group and 598 [35.8%] in the unadjusted ETTCP group). In the reduced ETTCP group, the severity of dysphagia, measured by the Bazaz-Yoo system in 3 randomized studies at 24 hours and at 4–8 weeks, was significantly lower (24 hours [standardized mean difference: −1.83, p = 0.04] and 4–8 weeks [standardized mean difference: −0.40, p = 0.05]). At 24 hours, the odds of developing dysphonia were significantly lower (OR 0.51, p = 0.002). The odds of dysphagia (24 hours: OR 0.77, p = 0.24; 1 week: OR 0.70, p = 0.47; 12 weeks: OR 0.58, p = 0.20) were lower, although not significantly, in the reduced ETTCP group. The odds of a patient having RLNP were significantly lower at all time points (24 hours: OR 0.38, p = 0.01; 12 weeks: OR 0.26, p = 0.03) when 3 randomized and 2 observational studies were analyzed. A subgroup analysis using only randomized studies demonstrated a similar trend in odds of having RLNP, yet without statistical significance (24 hours: OR 0.79, p = 0.60). All other statistically significant findings persisted with removal of any observational data.

CONCLUSIONS

Based on the current best available evidence, reduction of ETTCP after retractor placement in anterior cervical surgery may be a protective measure to decrease the severity of dysphagia and the odds of developing RLNP or dysphonia.

OBJECTIVE

Postprocedural infection is a consequential complication of neurosurgical intervention. Periprocedural antimicrobial prophylaxis is routinely administered to prevent infection, and in some cases, continued for extended periods while surgical drains remain in place. However, there is little evidence that extended antimicrobial administration is necessary to reduce postprocedural infection, and extended antimicrobials can be associated with harm, such as Clostridioides difficile infection. The authors sought to evaluate whether shortening the duration of postprocedural antimicrobial prophylaxis would decrease the incidence of C. difficile infection without increasing the incidence of postprocedural infection.

METHODS

In this retrospective study, two general neurosurgical cohorts were examined. In one cohort, postoperative antimicrobial prophylaxis was limited to 24 hours; in the other, some patients received extended postoperative antimicrobial prophylaxis while surgical drains or external ventricular drains (EVDs) remained in place. Rates of infection with C. difficile as well as postprocedural infection after surgery and EVD placement were compared.

RESULTS

Seven thousand two hundred four patients undergoing 8586 surgical procedures and 413 EVD placements were reviewed. The incidence of C. difficile infection decreased significantly from 0.5% per procedural encounter to 0.07% with the discontinuation of extended postprocedural antibiotics within 90 days of a procedure. Rates of postprocedural infection and EVD infection did not significantly change. Results were similar in subgroups of patients with closed suction drains as well as cranial and spine subgroups.

CONCLUSIONS

Discontinuation of extended antimicrobial prophylaxis was associated with a significant decrease in the incidence of C. difficile infection without a concomitant change in postprocedural infections or EVD-associated infection. This study provides evidence in support of specialtfy-wide discontinuation of extended postoperative antimicrobial prophylaxis, even in the presence of closed suction drains.

OBJECTIVE

There is a growing body of evidence demonstrating the benefits of diversity across many domains. However, neurosurgery consistently lags most of medicine in many aspects of diversity. Any inability to make progress in this arena is likely due to the multifactorial and complex nature of the issue, which makes it difficult to meaningfully measure and track diversity within the workforce. The goal of this pilot study was to assess the utilization of a multidimensional statistical model to quantify and assess diversity within neurosurgery. The authors sought to 1) assess the diversity of neurosurgery residents using Simpson’s Diversity Index and Sullivan’s Composite Diversity Index (CDI) and 2) determine if a medical school’s intrinsic academic opportunities and resources, indicated by US News & World Report’s (USNWR’s) best research medical schools ranking, are related to the number of neurosurgery residents produced per medical school.

METHODS

A cross-sectional study of all neurosurgery residents (projected graduation years 2020–2026) and 1st-year medical students (matriculating years 2016–2019) was undertaken. Biographical diversity data (gender and matriculation data) were collected from institutional websites between December 2019 and June 2020. The CDI expresses the diversity of a given population by representing the effective proportion of categories present across all diversity attributes and was calculated for neurosurgery residents and medical students. Statistical results are reported as the median and interquartile range.

RESULTS

Neurosurgery residency program CDI (0.21, IQR 0.16–0.25) was significantly less (p < 0.001) than medical school CDI (0.42, 0.37–0.48). There was no significant difference in CDI between top-40 and non–top 40 Doximity ranked research output neurosurgery residency programs (p = 0.35) or between top-40 and non–top 40 USNWR ranked research medical schools (p = 0.11). Over a 7-year period, top-40 ranked research medical schools produced significantly more (p < 0.001) neurosurgery residents (11.9, IQR 7.1–18.9) than the non–top 40 ranked research medical schools (5.6, IQR 2.6–8.5).

CONCLUSIONS

The authors demonstrated the feasibility of using a multidimensional statistical model as a measure to understand the complex issues of diversity. Their preliminary data suggested that neurosurgery’s challenge in achieving the desired diversity relates to uneven attraction and/or recruitment across an increasingly diverse medical student body. In recent years, neurosurgery has made great progress in the arena of diversity and has shown a strong desire to do more. Utilization of these diversity measures will help the neurosurgery field to monitor progress along this valuable journey.