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Benjamin C. Warf, Michael Dewan and John Mugamba

Object

Dandy-Walker complex (DWC) is a continuum of congenital anomalies comprising Dandy-Walker malformation (DWM), Dandy-Walker variant (DWV), Blake pouch cyst, and mega cisterna magna (MCM). Hydrocephalus is variably associated with each of these, and DWC-associated hydrocephalus has mostly been treated by shunting, often with 2-compartment shunting. There are few reports of management by endoscopic third ventriculostomy (ETV). This study is the largest series of DWC or DWM-associated hydrocephalus treated by ETV, and the first report of treatment by combined ETV and choroid plexus cauterization (ETV/CPC) in young infants with this association.

Methods

A retrospective review of the CURE Children's Hospital of Uganda clinical database between 2004 and 2010 identified 45 patients with DWC confirmed by CT scanning (25 with DWM, 17 with DWV, and 3 with MCM) who were treated for hydrocephalus by ETV/CPC. Three were excluded because of other potential causes of hydrocephalus (2 postinfectious and 1 posthemorrhagic).

Results

The median age at treatment was 5 months (88% of patients were younger than 12 months). There was a 2.4:1 male predominance among patients with DWV. An ETV/CPC (ETV only in one) was successful with no further operations in 74% (mean and median follow-up 24.2 and 20 months, respectively [range 6–65 months]). The rate of success was 74% for DWM, 73% for DWV, and 100% for MCM; 95% had an open aqueduct, and none required posterior fossa shunting.

Conclusions

Endoscopic treatment of DWC-associated hydrocephalus should be strongly considered as the primary management in place of the historical standard of creating shunt dependence.

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Scott L. Zuckerman, Cain S. Green, Kevin R. Carr, Michael C. Dewan, Peter J. Morone and J Mocco

Morbidity due to avoidable medical errors is a crippling reality intrinsic to health care. In particular, iatrogenic surgical errors lead to significant morbidity, decreased quality of life, and attendant costs. In recent decades there has been an increased focus on health care quality improvement, with a concomitant focus on mitigating avoidable medical errors. The most notable tool developed to this end is the surgical checklist. Checklists have been implemented in various operating rooms internationally, with overwhelmingly positive results. Comparatively, the field of neurosurgery has only minimally addressed the utility of checklists as a health care improvement measure. Literature on the use of checklists in this field has been sparse. Considering the widespread efficacy of this tool in other fields, the authors seek to raise neurosurgical awareness regarding checklists by reviewing the current literature.

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Scott L. Zuckerman, Andrew Kuhn, Michael C. Dewan, Peter J. Morone, Jonathan A. Forbes, Gary S. Solomon and Allen K. Sills

Object

Sports-related concussions (SRCs) represent a significant and growing public health concern. The vast majority of SRCs produce mild symptoms that resolve within 1–2 weeks and are not associated with imaging-documented changes. On occasion, however, structural brain injury occurs, and neurosurgical management and intervention is appropriate.

Methods

A literature review was performed to address the epidemiology of SRC with a targeted focus on structural brain injury in the last half decade. MEDLINE and PubMed databases were searched to identify all studies pertaining to structural head injury in sports-related head injuries.

Results

The literature review yielded a variety of case reports, several small series, and no prospective cohort studies.

Conclusions

The authors conclude that reliable incidence and prevalence data related to structural brain injuries in SRC cannot be offered at present. A prospective registry collecting incidence, management, and follow-up data after structural brain injuries in the setting of SRC would be of great benefit to the neurosurgical community.

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Travis R. Ladner, Michael C. Dewan, Matthew A. Day, Chevis N. Shannon, Luke Tomycz, Noel Tulipan and John C. Wellons III

OBJECT

The clinical significance of radiological measurements of the craniocervical junction in pediatric Chiari I malformation (CM-I) is yet to be fully established across the field. The authors examined their institutional experience with the pB–C2 line (drawn perpendicular to a line drawn between the basion and the posterior aspect of the C-2 vertebral body, at the most posterior extent of the odontoid process at the dural interface). The pB–C2 line is a measure of ventral canal encroachment, and its relationship with symptomatology and syringomyelia in pediatric CM-I was assessed.

METHODS

The authors performed a retrospective review of 119 patients at the Monroe Carell Jr. Children's Hospital at Vanderbilt University who underwent posterior fossa decompression with duraplasty, 78 of whom had imaging for review. A neuroradiologist retrospectively evaluated preoperative and postoperative MRI examinations performed in these 78 patients, measuring the pB–C2 line length and documenting syringomyelia. The pB–C2 line length was divided into Grade 0 (< 3 mm) and Grade I (≥ 3 mm). Statistical analysis was performed using the t-test for continuous variables and Fisher's exact test analysis for categorical variables. Multivariate logistic and linear regression analyses were performed to assess the relationship between pB–C2 line grade and clinical variables found significant on univariate analysis, controlling for age and sex.

RESULTS

The mean patient age was 8.5 years, and the mean follow-up duration was 2.4 years. The mean pB–C2 line length was 3.5 mm (SD 2 mm), ranging from 0 to 10 mm. Overall, 65.4% of patients had a Grade I pB–C2 line. Patients with Grade I pB–C2 lines were 51% more likely to have a syrinx than those with Grade 0 pB–C2 lines (RR 1.513 [95% CI 1.024–2.90], p = 0.021) and, when present, had greater syrinx reduction (3.6 mm vs 0.2 mm, p = 0.002). Although there was no preoperative difference in headache incidence, postoperatively patients with Grade I pB–C2 lines were 69% more likely to have headache reduction than those with Grade 0 pB–C2 lines (RR 1.686 [95% CI 1.035–2.747], p = 0.009). After controlling for age and sex, pB–C2 line grade remained an independent correlate of headache improvement and syrinx reduction.

CONCLUSIONS

Ventral canal encroachment may explain the symptomatology of select patients with CM-I. The clinical findings presented suggest that patients with Grade I pB–C lines2, with increased ventral canal obstruction, may experience a higher likelihood of syrinx reduction and headache resolution from decompressive surgery with duraplasty than those with Grade 0 pB–C2 lines.

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Travis R. Ladner, Michael C. Dewan, Matthew A. Day, Chevis N. Shannon, Luke Tomycz, Noel Tulipan and John C. Wellons III

OBJECT

Osseous anomalies of the craniocervical junction are hypothesized to precipitate the hindbrain herniation observed in Chiari I malformation (CM-I). Previous work by Tubbs et al. showed that posterior angulation of the odontoid process is more prevalent in children with CM-I than in healthy controls. The present study is an external validation of that report. The goals of our study were 3-fold: 1) to externally validate the results of Tubbs et al. in a different patient population; 2) to compare how morphometric parameters vary with age, sex, and symptomatology; and 3) to develop a correlative model for tonsillar ectopia in CM-I based on these measurements.

METHODS

The authors performed a retrospective review of 119 patients who underwent posterior fossa decompression with duraplasty at the Monroe Carell Jr. Children’s Hospital at Vanderbilt University; 78 of these patients had imaging available for review. Demographic and clinical variables were collected. A neuroradiologist retrospectively evaluated preoperative MRI examinations in these 78 patients and recorded the following measurements: McRae line length; obex displacement length; odontoid process parameters (height, angle of retroflexion, and angle of retroversion); perpendicular distance to the basion-C2 line (pB–C2 line); length of cerebellar tonsillar ectopia; caudal extent of the cerebellar tonsils; and presence, location, and size of syringomyelia. Odontoid retroflexion grade was classified as Grade 0, > 90°; Grade I,85°–89°; Grade II, 80°–84°; and Grade III, < 80°. Age groups were defined as 0–6 years, 7–12 years, and 13–17 years at the time of surgery. Univariate and multivariate linear regression analyses, Kruskal-Wallis 1-way ANOVA, and Fisher’s exact test were performed to assess the relationship between age, sex, and symptomatology with these craniometric variables.

RESULTS

The prevalence of posterior odontoid angulation was 81%, which is almost identical to that in the previous report (84%). With increasing age, the odontoid height (p < 0.001) and pB–C2 length (p < 0.001) increased, while the odontoid process became more posteriorly inclined (p = 0.010). The pB–C2 line was significantly longer in girls (p = 0.006). These measurements did not significantly correlate with symptomatology. Length of tonsillar ectopia in pediatric CM-I correlated with an enlarged foramen magnum (p = 0.023), increasing obex displacement (p = 0.020), and increasing odontoid retroflexion (p < 0.001).

CONCLUSIONS

Anomalous bony development of the craniocervical junction is a consistent feature of CM-I in children. The authors found that the population at their center was characterized by posterior angulation of the odontoid process in 81% of cases, similar to findings by Tubbs et al. (84%). The odontoid process appeared to lengthen and become more posteriorly inclined with age. Increased tonsillar ectopia was associated with more posterior odontoid angulation, a widened foramen magnum, and an inferiorly displaced obex.

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Michael C. Dewan, Reid C. Thompson, Steven N. Kalkanis, Fred G. Barker II and Constantinos G. Hadjipanayis

OBJECTIVE

Antiepileptic drugs (AEDs) are often administered prophylactically following brain tumor resection. With conflicting evidence and unestablished guidelines, however, the nature of this practice among tumor surgeons is unknown.

METHODS

On November 24, 2015, a REDCap (Research Electronic Database Capture) survey was sent to members of the AANS/CNS Section on Tumors to query practice patterns.

RESULTS

Responses were received from 144 individuals, including 18.8% of board-certified neurosurgeons surveyed (across 86 institutions, 16 countries, and 5 continents). The majority reported practicing in an academic setting (85%) as a tumor specialist (71%). Sixty-three percent reported always or almost always prescribing AED prophylaxis postoperatively in patients with a supratentorial brain tumor without a prior seizure history. Meanwhile, 9% prescribed occasionally and 28% rarely prescribed AED prophylaxis. The most common agent was levetiracetam (85%). The duration of seizure prophylaxis varied widely: 25% of surgeons administered prophylaxis for 7 days, 16% for 2 weeks, 21% for 2 to 6 weeks, and 13% for longer than 6 weeks. Most surgeons (61%) believed that tumor pathology influences epileptogenicity, with high-grade glioma (39%), low-grade glioma (31%), and metastases (24%) carrying the greatest seizure risk. While the majority used prophylaxis, 62% did not believe or were unsure if prophylactic AEDs reduced seizures postoperatively. The vast majority (82%) stated that a well-designed randomized trial would help guide their future clinical decision making.

CONCLUSIONS

Wide knowledge and practice gaps exist regarding the frequency, duration, and setting of AED prophylaxis for seizure-naive patients undergoing brain tumor resection. Acceptance of universal practice guidelines on this topic is unlikely until higher-level evidence supporting or refuting the value of modern seizure prophylaxis is demonstrated.

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Michael C. Dewan, Gabrielle A. White-Dzuro, Philip R. Brinson, Reid C. Thompson and Lola B. Chambless

OBJECTIVE

Seizures are among the most common perioperative complications in patients undergoing craniotomy for brain tumor resection and have been associated with increased disease progression and decreased survival. Little evidence exists regarding the relationship between postoperative seizures and hospital quality measures, including length of stay (LOS), disposition, and readmission. The authors sought to address these questions by analyzing a glioma population over 15 years.

METHODS

A retrospective cohort study was used to evaluate the outcomes of patients who experienced a postoperative seizure. Patients with glioma who underwent craniotomy for resection between 1998 and 2013 were enrolled in the institutional tumor registry. Basic data, including demographics and comorbidities, were recorded in addition to hospitalization details and complications. Seizures were diagnosed by clinical examination, observation, and electroencephalography. The Student t-test and chi-square test were used to analyze differences in the means between continuous and categorical variables, respectively. Multivariate logistic and linear regression was used to compare multiple clinical variables against hospital quality metrics and survival figures, respectively.

RESULTS

In total, 342 patients with glioma underwent craniotomy for first-time resection. The mean age was 51.0 ± 17.3 years, 192 (56.1%) patients were male, and the median survival time for all grades was 15.4 months (range 6.2–24.0 months). High-grade glioma (Grade III or IV) was seen in 71.9% of patients. Perioperative antiepileptic drugs were administered to 88% of patients. Eighteen (5.3%) patients experienced a seizure within 14 days postoperatively, and 9 (50%) of these patients experienced first-time seizures. The mean time to the first postoperative seizure was 4.3 days (range 0–13 days). There was no significant association between tumor grade and the rate of perioperative seizure (Grade I, 0%; II, 7.0%; III, 6.1%; IV, 5.2%; p = 0.665). A single ictal episode occurred in 11 patients, while 3 patients experienced 2 seizures and 4 patients developed 3 or more seizures. Compared with their seizure-free counterparts, patients who experienced a perioperative seizure had an increased average hospital (6.8 vs 3.6 days, p = 0.032) and ICU LOS (5.4 vs 2.3 days; p < 0.041). Seventy-five percent of seizure-free patients were discharged home in comparison with 55.6% of seizure patients (p = 0.068). Patients with a postoperative seizure were significantly more likely to visit the emergency department within 90 days (44.4% vs 19.0%; OR 3.41 [95% CI 1.29–9.02], p = 0.009) and more likely to be readmitted within 90 days (50.0% vs 18.4%; OR 4.45 [95% CI 1.69–11.70], p = 0.001). In addition, seizure-free patients had a longer median overall survival (15.6 months [interquartile range 6.6–24.4 months] vs 3.0 months [interquartile range 1.0–25.0 months]; p = 0.013).

CONCLUSIONS

Patients with perioperative seizures following glioma resection required longer hospital and ICU LOS, were readmitted at higher rates than seizure-free patients, and experienced shorter overall survival. Biological and clinical factors that predispose to the development of seizures after glioma surgery portend a worse outcome. Efforts to identify these factors and reduce the risk of postoperative seizure should remain a priority among neurosurgical oncologists.

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Michael C. Dewan, Jaims Lim, Clinton D. Morgan, Stephen R. Gannon, Chevis N. Shannon, John C. Wellons III and Robert P. Naftel

OBJECTIVE

Endoscopic third ventriculostomy with choroid plexus cauterization (ETV/CPC) offers an alternative to shunt treatment for infantile hydrocephalus. Diagnosing treatment failure is dependent on infantile hydrocephalus metrics, including head circumference, fontanel quality, and ventricle size. However, it is not clear to what degree these metrics should be expected to change after ETV/CPC. Using these clinical metrics, the authors present and analyze the decision making in cases of ETV/CPC failure.

METHODS

Infantile hydrocephalus metrics, including bulging fontanel, head circumference z-score, and frontal and occipital horn ratio (FOHR), were compared between ETV/CPC failures and successes. Treatment outcome predictive values of metrics individually and in combination were calculated.

RESULTS

Forty-four patients (57% males, median age 1.2 months) underwent ETV/CPC for hydrocephalus; of these patients, 25 (57%) experienced failure at a median time of 51 days postoperatively. Patients experiencing failure were younger than those experiencing successful treatment (0.8 vs 3.9 months, p = 0.01). During outpatient follow-up, bulging anterior fontanel, progressive macrocephaly, and enlarging ventricles each demonstrated a positive predictive value (PPV) of no less than 71%, but a bulging anterior fontanel remained the most predictive indicator of ETV/CPC failure, with a PPV of 100%, negative predictive value of 73%, and sensitivity of 72%. The highest PPVs and specificities existed when the clinical metrics were present in combination, although sensitivities decreased expectedly. Only 48% of failures were diagnosed on the basis all 3 hydrocephalus metrics, while only 37% of successes were negative for all 3 metrics. In the remaining 57% of patients, a diagnosis of success or failure was made in the presence of discordant data.

CONCLUSIONS

Successful ETV/CPC for infantile hydrocephalus was evaluated in relation to fontanel status, head growth, and change in ventricular size. In most patients, a designation of failure or success was made in the setting of discordant data.

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Michael C. Dewan, Jaims Lim, Chevis N. Shannon and John C. Wellons III

OBJECTIVE

Up to one-third of patients with a posterior fossa brain tumor (PFBT) will experience persistent hydrocephalus mandating permanent CSF diversion. The optimal hydrocephalus treatment modality is unknown; the authors sought to compare the durability between endoscopic third ventriculostomy (ETV) and ventriculoperitoneal shunt (VPS) therapy in the pediatric population.

METHODS

The authors conducted a systematic review of articles indexed in PubMed between 1986 and 2016 describing ETV and/or VPS treatment success/failure and time-to-failure rate in patients < 19 years of age with hydrocephalus related to a PFBT. Additionally, the authors conducted a retrospective review of their institutional series of PFBT patients requiring CSF diversion. Patient data from the systematic review and from the institutional series were aggregated and a time-to-failure analysis was performed comparing ETV and VPS using the Kaplan-Meier method.

RESULTS

A total of 408 patients were included from 12 studies and the authors' institutional series: 284 who underwent ETV and 124 who underwent VPS placement. The analysis included uncontrolled studies with variable method and timing of CSF diversion and were subject to surgeon bias. No significant differences between cohorts were observed with regard to age, sex, tumor grade or histology, metastatic status, or extent of resection. The cumulative failure rate of ETV was 21%, whereas that of VPS surgery was 29% (p = 0.105). The median time to failure was earlier for ETV than for VPS surgery (0.82 [IQR 0.2–1.8] vs 4.7 months [IQR 0.3–5.7], p = 0.03). Initially the ETV survival curve dropped sharply and then stabilized around 2 months. The VPS curve fell gradually but eventually crossed below the ETV curve at 5.7 months. Overall, a significant survival advantage was not demonstrated for one procedure over the other (p = 0.21, log-rank). However, postoperative complications were higher following VPS (31%) than ETV (17%) (p = 0.012).

CONCLUSIONS

ETV failure occurred sooner than VPS failure, but long-term treatment durability may be higher for ETV. Complications occurred more commonly with VPS than with ETV. Limited clinical conclusions are drawn using this methodology; the optimal treatment for PFBT-related hydrocephalus warrants investigation through prospective studies.