Experience in shunt management on revision free survival in infants with myelomeningocele

CSF shunting in myelomeningocele-related hydrocephalus and the role of prenatal imaging

OBJECTIVE

Hydrocephalus is commonly associated with myelomeningocele (MMC). Indication and timing of cerebrospinal fluid (CSF) shunting are still a topic of discussion. The aim of this study was to investigate whether the analysis of prenatal cerebral imaging studies could provide information that is predictive of the necessity of CSF shunting in the postnatal period.

MATERIAL AND METHODS

Among 73 infants operated on because of MMC between January 2003 and June 2020, 50 had undergone prenatal and postnatal MRI studies and were considered for analysis. For each patient, frontal horn width, atrial ventricle diameter, third ventricle diameter, and subarachnoid spaces (sinocortical width, craniocortical width, and the interhemispheric width) have been measured on prenatal, postnatal, and a follow-up MRI study. The need of CSF shunting device placement in relation to prenatal and early postnatal MRI data was investigated.

RESULTS

Of the 50 infants, 31 (62%) developed a progressive hydrocephalus. Of these, 30 needed a CSF shunt and the majority of them (n=29) was operated on within 28 days after birth. One patient needed CSF shunt implantation at 45 days after birth and one child developed a late progressive hydrocephalus, successfully treated by ETV alone, at 14.2 months of age. All patients with an atrial ventricle diameter greater than 1.9 cm and a 3rd ventricle diameter larger than 0.3 cm on antenatal third trimester imaging have undergone CSF shunting within 1 month after birth. Conversely, all the children that did not undergo a CSF shunt placement showed an atrial cerebral ventricle diameter inferior to 1.2 cm and a 3rd ventricle width < 0.3 cm on antenatal imaging. Frontal horn width and subarachnoid CSF spaces' evolution did not seem to play a role.

CONCLUSION

The prenatal MRI assessment of the associated prenatal ventriculomegaly in MMC provides parameters that have a predictive value heralding the probability of a CSF diversion procedure after birth. In the same way, the analysis of intrauterine MRI studies may identify those subjects that are less at risk of developing a progressive hydrocephalus after birth, therefore encouraging a more cautious attitude towards the early implantation of CSF shunting devices in the current clinical practice.

Reduced rates of infection after myelomeningocele closure associated with standard perioperative antibiotic treatment with ampicillin and gentamicin

PURPOSE

Postnatal closure of a myelomeningocele (MMC) is a complex procedure with frequent complications following surgery. Bacterial colonization of the placode may cause infection and subsequent complications. The objectives of this study were to determine the preoperative bacterial colonization rates, to assess the antibiotic regimen, and to evaluate the overall postoperative infection rate.

METHODS

All consecutive patients undergoing MMC closure in our hospital from January 2010 to January 2020 were evaluated. Epidemiological data, surgical data, complication characteristics, and microbiological results were documented.

RESULTS

A total of 45 patients were evaluated; in 41 patients, a wound swab of the placode was performed directly before MMC closure (91%). All patients received a prophylactic antibiotic treatment for a mean of 5.6 ± 2.7 days around the performed MMC closure. In three patients with a wound swab (7.3%), a bacterial colonization could be detected-none of the patients developed a subsequent infection. Overall, 7 other patients developed an infection (15.6%), three local surgical site infections, and four shunt-related infections. After applying a standardized perioperative prophylactic antibiotic treatment with ampicillin and gentamicin, the infection rate was observed to be lower compared with that of a non-standardized treatment (6% vs. 45%; p = 0.019).

CONCLUSIONS

In neonates who undergo MMC closure in the first 48 h after birth, the colonization rate of the placode was lower than previously reported. While the data presented cannot proof the benefit of a perioperative antibiotic prophylaxis, as compared with no prophylaxis, infection rates are low with a standardized antibiotic regime comprising ampicillin and gentamicin.

Gravitational shunt valves in hydrocephalus to challenge the sequelae of over-drainage

INTRODUCTION

In hydrocephalus treatment, ventriculo-peritoneal shunts (VPS) have become the most relevant therapy for seven decades among other treatment options. Due to the hydrostatic pressure in vertical position, CSF diversion is somehow non-physiological. The integration of gravitational valves in VPS was established to counteract the hydrostatic draining force and to approach a physiological condition of the cerebrospinal diverting system. Numerous clinical studies have shown that gravitational valves are able to reduce secondary complications of VPS treatment. It remains a challenge for the treating neurosurgeon to select the correct valve resistance based on individual anatomies and different etiologies of hydrocephalus as well as varying levels of activity of the patient.

AREAS COVERED

This review covers the development of gravitational shunt valves from historical, theoretical and clinical aspects for pediatric and adult etiologies of hydrocephalus. We discuss the role of gravitational shunt valves in preventing over-drainage issues and present the state-of-the-art literature. Furthermore, ongoing prospective trials are presented.

EXPERT OPINION

Counteracting the hydrostatic force by selecting the correct valve in a VPS system to achieve physiological balance in CSF diversion during vertical and horizontal body changes has become the current standard for hydrocephalus management. Gravitational shunt valves reliably address this need to minimize over-drainage events in the vertical position without affecting the CSF flow in the horizontal position. The results of ongoing prospective studies on the safety and efficacy of adjustable gravitational valves are still pending. Due to the complexity of the CSF flow, lifelong follow-up care for patients with VPS is critical.

A 12-year single-center retrospective analysis of antisiphon devices to prevent proximal ventricular shunt obstruction for hydrocephalus

OBJECTIVE

Recent evidence points to gravity-dependent chronic shunt overdrainage as a significant, if not leading, cause of proximal shunt failure. Yet, shunt overdrainage or siphoning persists despite innovations in valve technology. The authors examined the effectiveness of adding resistance to flow in shunt systems via antisiphon devices (ASDs) in preventing proximal shunt obstruction.

METHODS

A retrospective observational cohort study was completed on patients who had an ASD (or additional valve) added to their shunt system between 2004 and 2016. Detailed clinical, radiographic, and surgical findings were examined. Shunt failure rates were compared before and after ASD addition.

RESULTS

Seventy-eight patients with shunted hydrocephalus were treated with placement of an ASD several centimeters distal to the primary valve. The records of 12 of these patients were analyzed separately due to a complex shunt revision history (i.e., > 10 lifetime shunt revisions). The authors found that adding an ASD decreased the 1-year ventricular catheter obstruction rates in the "simple" and "complex" groups by 67.3% and 75.8%, respectively, and the 5-year rates by 43.3% and 65.6%, respectively. The main long-term ASD complication was ASD removal for presumed valve pressure intolerance in 5 patients.

CONCLUSIONS

Using an ASD may result in significant reductions in ventricular catheter shunt obstruction rates. If confirmed with prospective studies, this observation would lend further evidence that chronic shunt overdrainage is a central cause of shunt malfunction, and provide pilot data to establish clinical and laboratory studies that assess optimal ASD type, number, and position, and eventually develop shunt valve systems that are altogether resistant to siphoning.