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Michael C. Dewan, Jaims Lim, Stephen R. Gannon, David Heaner, Matthew C. Davis, Brandy Vaughn, Joshua J. Chern, Brandon G. Rocque, Paul Klimo Jr., John C. Wellons III and Robert P. Naftel

OBJECTIVE

It has been suggested that the treatment of infant hydrocephalus results in different craniometric changes depending upon whether ventriculoperitoneal shunt (VPS) placement or endoscopic third ventriculostomy with choroid plexus cauterization (ETV/CPC) is performed. Without an objective and quantitative description of expected changes to the infant cranium and ventricles following ETV/CPC, asserting successful treatment of hydrocephalus is difficult. By comparing infants successfully treated via ETV/CPC or VPS surgery, the authors of this study aimed to define the expected postoperative cranial and ventricular alterations at the time of clinical follow-up.

METHODS

Patients who underwent successful treatment of hydrocephalus at 4 institutions with either VPS placement or ETV/CPC were matched in a 3:1 ratio on the basis of age and etiology. Commonly used cranial parameters (including head circumference [HC], HC z-score, fontanelle status, and frontooccipital horn ratio [FOHR]) were compared pre- and postoperatively between treatment cohorts. First, baseline preoperative values were compared to ensure cohort equivalence. Next, postoperative metrics, including the relative change in metrics, were compared between treatment groups using multivariate linear regression.

RESULTS

Across 4 institutions, 18 ETV/CPC-treated and 54 VPS-treated infants with hydrocephalus were matched and compared at 6 months postoperatively. The most common etiologies of hydrocephalus were myelomeningocele (61%), followed by congenital communicating hydrocephalus (17%), aqueductal stenosis (11%), and intraventricular hemorrhage (6%). The mean age at the time of CSF diversion was similar between ETV/CPC- and VPS-treated patients (3.4 vs 2.9 months; p = 0.69), as were all preoperative cranial hydrocephalus metrics (p > 0.05). Postoperatively, the ventricle size FOHR decreased significantly more following VPS surgery (−0.15) than following ETV/CPC (−0.02) (p < 0.001), yielding a lower postoperative FOHR in the VPS arm (0.42 vs 0.51; p = 0.01). The HC percentile was greater in the ETV/CPC cohort than in the VPS-treated patients (76th vs 54th percentile; p = 0.046). A significant difference in the postoperative z-score was not observed. With both treatment modalities, a bulging fontanelle reliably normalized at last follow-up.

CONCLUSIONS

Clinical and radiographic parameters following successful treatment of hydrocephalus in infants differed between ETV/CPC and VPS treatment. At 6 months post-ETV/CPC, ventricle size remained unchanged, whereas VPS-treated ventricles decreased to a near-normal FOHR. The HC growth control between the procedures was similar, although the final HC percentile may be lower after VPS. The fontanelle remained a reliable indicator of success for both treatments. This study establishes expected cranial and ventricular parameters following ETV/CPC, which may be used to guide preoperative counseling and postoperative decision making.

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Michael C. Dewan, Abbas Rattani, Rania Mekary, Laurence J. Glancz, Ismaeel Yunusa, Ronnie E. Baticulon, Graham Fieggen, John C. Wellons III, Kee B. Park and Benjamin C. Warf

OBJECTIVE

Hydrocephalus is one of the most common brain disorders, yet a reliable assessment of the global burden of disease is lacking. The authors sought a reliable estimate of the prevalence and annual incidence of hydrocephalus worldwide.

METHODS

The authors performed a systematic literature review and meta-analysis to estimate the incidence of congenital hydrocephalus by WHO region and World Bank income level using the MEDLINE/PubMed and Cochrane Database of Systematic Reviews databases. A global estimate of pediatric hydrocephalus was obtained by adding acquired forms of childhood hydrocephalus to the baseline congenital figures using neural tube defect (NTD) registry data and known proportions of posthemorrhagic and postinfectious cases. Adult forms of hydrocephalus were also examined qualitatively.

RESULTS

Seventy-eight articles were included from the systematic review, representative of all WHO regions and each income level. The pooled incidence of congenital hydrocephalus was highest in Africa and Latin America (145 and 316 per 100,000 births, respectively) and lowest in the United States/Canada (68 per 100,000 births) (p for interaction < 0.1). The incidence was higher in low- and middle-income countries (123 per 100,000 births; 95% CI 98–152 births) than in high-income countries (79 per 100,000 births; 95% CI 68–90 births) (p for interaction < 0.01). While likely representing an underestimate, this model predicts that each year, nearly 400,000 new cases of pediatric hydrocephalus will develop worldwide. The greatest burden of disease falls on the African, Latin American, and Southeast Asian regions, accounting for three-quarters of the total volume of new cases. The high crude birth rate, greater proportion of patients with postinfectious etiology, and higher incidence of NTDs all contribute to a case volume in low- and middle-income countries that outweighs that in high-income countries by more than 20-fold. Global estimates of adult and other forms of acquired hydrocephalus are lacking.

CONCLUSIONS

For the first time in a global model, the annual incidence of pediatric hydrocephalus is estimated. Low- and middle-income countries incur the greatest burden of disease, particularly those within the African and Latin American regions. Reliable incidence and burden figures for adult forms of hydrocephalus are absent in the literature and warrant specific investigation. A global effort to address hydrocephalus in regions with the greatest demand is imperative to reduce disease incidence, morbidity, mortality, and disparities of access to treatment.

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Abbas Rattani, Michael C. Dewan, Vickie Hannig, Robert P. Naftel, John C. Wellons III and Lori C. Jordan

The authors present a case of monozygotic twins with hereditary hemorrhagic telangiectasia (HHT) who experienced cerebral arteriovenous malformation (AVM) hemorrhage at a very young age. The clinical variables influencing HHT-related AVM rupture are discussed, and questions surrounding the timing of screening and intervention are explored. This is only the second known case of monozygotic HHT twins published in the medical literature, and the youngest pair of first-degree relatives to experience AVM-related cerebral hemorrhage. Evidence guiding the screening and management of familial HHT is lacking, and cases such as this underscore the need for objective and validated protocols.

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Nishit Mummareddy, Michael C. Dewan, Michael R. Mercier, Robert P. Naftel, John C. Wellons III and Christopher M. Bonfield

OBJECTIVE

The authors aimed to provide an updated and consolidated report on the epidemiology, management, and functional outcome of cases of myelomeningocele (MMC) in patients with scoliosis.

METHODS

A comprehensive literature search was performed using MEDLINE, Embase, Google Scholar, and the Cochrane Database of Systematic Reviews on cases of MMC in patients with scoliosis between 1980 and 2016. The initial search yielded 670 reports. After removing duplicates and applying inclusion criteria, we included 32 full-text original articles in this study.

RESULTS

Pooled statistical analysis of the included articles revealed the prevalence of scoliosis in MMC patients to be 53% (95% CI 0.42–0.64). Slightly more females (56%) are affected with both MMC and scoliosis than males. Motor level appears to be a significant predictor of prevalence, but not severity, of scoliosis in MMC patients. Treatment options for these patients include tethered cord release (TCR) and fusion surgeries. Curvature improvement and stabilization after TCR may be limited to patients with milder (< 50°) curves. Meanwhile, more aggressive fusion procedures such as a combined anterior-posterior approach may result in more favorable long-term scoliosis correction, albeit with greater complication rates. Quality of life metrics including ambulatory status and sitting stability are influenced by motor level of the lesion as well as the degree of the scoliosis curvature.

CONCLUSIONS

Scoliosis is among the most common and challenging comorbidities from which patients with MMC suffer. Although important epidemiological and management trends are evident, larger, prospective studies are needed to discover ways to more accurately counsel and more optimally treat these patients.

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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.

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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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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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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.