What is the optimal drainage pressure in obstructive tumors hydrocephalus? Analysis of factors underlying valve overdrainage, case review and development of surgical protocol

https://doi.org/10.59156/revista.v36i04.594

Abstract

Background: Hydrocephalus is a common complication in CNS tumors pathology. The placement of ventriculoperitoneal shunt in these cases is, to date, the standard practice to treat this pathology and prevent the complications and comorbidities that it entails. At present, there is no protocol or initial valve pressure established for these patients, in whom we have observed a tendency toward overdrainage of cerebrospinal fluid (CSF).

The objective of this work is to analyze our experience in the treatment of obstructive hydrocephalus secondary to tumor pathology, determine factors related to the occurrence of overdrainage, its therapeutic management and subsequently protocolize in a simple and economical way the placement of this type of prosthesis as well as identify a therapeutic pressure that reduces the risk of overdrainage.

Methods: Monocentric, analytical, retrospective study of a cohort of patients operated on at our institution for obstructive hydrocephalus secondary to tumors, between the years 2013-2022.

Medical records, images and surgical protocols were analyzed. Those patients who developed overdrainage were identified. Subsequently, the demographic, clinical and therapeutic variables involved in it were analyzed using a multivariate explanatory statistical model.

In a second stage, a quick, simple, and economical protocol is proposed to determine the optimal pressure within each case.

Results: Among the 56 patients included, 32 patients (57%) presented overdrainage; 10 patients (18%) presented hygromas on postoperative images, and of these, 3 patients (5.4%) required surgical interventions. 94% of overdrains occurred at pressures less than or equal to 160 mmH₂0. Likewise, 8 of the 11 patients with non-adjustable medium fixed pressure shunt (100-110 mmH₂0) presented overdrainage.

In 27% of patients, valve pressure had to be increased because of clinical or radiological findings of overdrainage.

Conclusion: Hydrocephalus secondary to tumors presents a different behavior than normotensive ones. The rate of overdrainage in these patients is higher and therefore must be considered as a possible relevant complication. Given the heterogeneity of tumors, each patient has different CSF pressures and therefore treatment must be individualized. We propose the use of the intrasurgical pressure measurement protocol to place the shunt at the optimal pressure for each patient, and thus avoid CSF overdrainage.