Myelomeningocele-associated hydrocephalus: nationwide analysis and systematic review

Myelomeningocele (MMC), the most severe form of spina bifida, is characterized by protrusion of the meninges and spinal cord through a defect in the vertebral arches. The management and prevention of MMC-associated hydrocephalus has evolved since its initial introduction with regard to treatment of MMC defect, MMC-associated hydrocephalus treatment modality, and timing of hydrocephalus treatment.

The Nationwide Inpatient Sample (NIS) database from the years 1998-2014 was reviewed and neonates with spina bifida and hydrocephalus status were identified. Timing of hydrocephalus treatment, delayed treatment (DT) versus simultaneous MMC repair with hydrocephalus treatment (ST), and treatment modality (ETV vs ventriculoperitoneal shunt [VPS]) were analyzed. Yearly trends were assessed with univariable logarithmic regression. Multivariable logistic regression identified correlates of inpatient shunt failure. A PRISMA systematic literature review was conducted that analyzed data from studies that investigated 1) MMC closure technique and hydrocephalus rate, 2) hydrocephalus treatment modality, and 3) timing of hydrocephalus treatment.

A weighted total of 10,627 inpatient MMC repairs were documented in the NIS, 8233 (77.5%) of which had documented hydrocephalus: 5876 (71.4%) were treated with VPS, 331 (4.0%) were treated with ETV, and 2026 (24.6%) remained untreated on initial inpatient stay. Treatment modality rates were stable over time; however, hydrocephalic patients in later years were less likely to receive hydrocephalus treatment during initial inpatient stay (odds ratio [OR] 0.974, p = 0.0331). The inpatient hydrocephalus treatment failure rate was higher for patients who received ETV treatment (17.5% ETV failure rate vs 7.9% VPS failure rate; p = 0.0028). Delayed hydrocephalus treatment was more prevalent in the later time period (77.9% vs 69.5%, p = 0.0287). Predictors of inpatient shunt failure included length of stay, shunt infection, jaundice, and delayed treatment. A longer time between operations increased the likelihood of inpatient shunt failure (OR 1.10, p < 0.0001). However, a meta-analysis of hydrocephalus timing studies revealed no difference between ST and DT with respect to shunt failure or infection rates.

From 1998 to 2014, hydrocephalus treatment has become more delayed and the number of hydrocephalic MMC patients not treated on initial inpatient stay has increased. Meta-analysis demonstrated that shunt malfunction and infection rates do not differ between delayed and simultaneous hydrocephalus treatment.