Mechanical shunt failure in hydrocephalus: a common but remediable complication with technical nuances

Abstract

A ventriculoperitoneal (VP) shunt is a cerebral shunt that diverts excess cerebrospinal fluid (CSF).Obstruction in the normal outflow or decreased absorption of the fluid is the usual cause. Hydrocephalus is treated by cerebral shunts.In paediatric patients, untreated hydrocephalus can be lethal and leads to many adverse effects including increase irritabilities, chronic headaches, learning difficulties, visual disturbances, and, in more advanced cases, severe mental retardation. Malfunction of the shunt with excess CSF accumulated can increase the intracranial pressure resulting in cerebral oedema and ultimately herniation. To study and evaluate the mechanical causes of shunt failure and their surgical remedies and reduce the preventable morbidity, cost and mortality associated with shunt failure. We conducted a prospective observational study including 70 patients who developed pure mechanical shunt failure for the first time from 2017 to 2020 in the Department of Neurosurgery Sher-i-kashmir Institute of Medical Sciences. Patients with previous shunt surgeries which include VP shunting and shunt revision or failure and shunt infections were excluded. Identity of all the patients has been kept anonymus. Written informed consent was obtained from all patients or their guardians in case of minors. Shunt malfunction was in the form of catheter misplacement, kinking, displacement from the ventricle or peritoneal cavity, disconnection, migration,inadvertent suturing of the catheter, air in shunt bulb. We found kinking at the proximal end in 25 (35%) patients as the most common cause of shunt failure. It was mostly as a result of inadequate and less spacious tunnelling made for the reservoir. Inadvertant suturing of shunt while closing abdomen in 7 (10%), shunt disconnection in 6 (8.5%), air in shunt bulb in 2 (2.8%), wrong placement at ventricular end in 10 (14.2%), shunt migration into the brain parenchyma in 5 (7.1%), shunt migration through the anal canal in 1(1.4%), pseudomeningocele around catheter valve in 3 (4.2%), placement of lower end into the preperitoneal space in 4 (5.7%) patients. Shunt surgery is seemingly a straightforward operation for neurosurgeons. But considering the incidence of shunt failure and its associated morbidity and mortality, it should always be done with trepidation and extreme caution. Exclusive mechanical shunt malfunction is a major concern and leads to great deal of morbidity in the shunt operations. However, there are trivial remedies and technical nuances which needs to be followed during surgery to avoid these complications.