Endoscopic observations of blocked ventriculoperitoneal (VP) shunt: a step toward better understanding of shunt obstruction and its removal

Abstract

Objectives. Most of our understanding of ventriculoperitoneal (VP) shunt blockage (ventricular end) is based on in vitro studies of blocked VP shunts. Not much information is available regarding the in vivo changes that occur in the tube and in the surrounding ventricle. The primary aim of our study was to observe and analyse these changes, directly, through the endoscope, in patients with blocked shunts undergoing an endoscopic third ventriculostomy (ETV). Based on these findings, we have also suggested criteria for safe removal of the VP shunt tube following ETV. Material and methods. ETV was performed with standard technique in patients with blocked VP shunt. The ventricular end of the shunt tube was inspected through the endoscope, for changes in ventricle linings as well as in the shunt tube. These changes were correlated with the age of the patient, etiology of HC, type or make of the shunt tube, duration of shunt placement to ETV and the CSF findings. Results. Fifty-three patients of blocked VP shunt underwent ETV from July 2006 to April 2010. Thirty patients had Chhabra (CH) V P Shunt (Surgiwear, India) and 23 had ceredrain (CD) shunt (Hindustan Latex, India). The age of the patients ranged from 2 months to 60 years (mean – 13.33 years.). Various causes of hydrocephalus (HC) included congenital hydrocephalus (aqueductal stenosis) in 18 patients, post-meningitis hydrocephalus (PMH) in 32 cases, neuro-cysticercosis (NCC) in 2 patients and intraventricular haemorrhagic (IVH) in 1 patient. Clinical and radiological improvement occurred in 33 (62.21%), and 24 (45%) patients, respectively. Freedom from shunt was attained in 20 (38%) patients. The changes around the shunt tube were seen in 41 (77%). Hyperaemia and neovascularised ependyma was seen in 20 (37%) and 15 (28%) patients. Encasement of the tube was seen in 41%. Ependymal growth and neovascularised shunt tubes were noticed in 15% each. Choroid plexus blocking the tube was seen in only four cases (7%). VP shunt was revised in 14 patients (26.4%). Patient with infective etiology had more changes (p < 0.005). Age, CSF findings and make of shunt tube had no relation with endoscopic observations (p< 0.02). Conclusions. ETV has a role in shunt failures. It can offer patient a chance of shunt free life. Endoscopic observation of shunt tube and ventricle can unfold several interesting in vivo findings pertaining to shunt obstruction. Shunt should only be removed if there are no adhesions and neovascularisation.