Outlet fenestration for isolated fourth ventricle with and without an internal shunt

Abstract

Conventional shunting of isolated fourth ventricle is notorious for leading to frequent and severe complications. We present four patients with isolated fourth ventricle who have been treated with open posterior fossa surgery together with either outlet fenestration alone or outlet fenestration and a fourth ventricle-spinal subarachnoid space (SSS) shunt. A survey of the relevant literature did not yield any other case reports of fourth ventricle shunting to the SSS under such circumstances. This paper discusses the reasons for choosing this mode of treatment. The main advantage of this technique is that the catheter is inserted along the anatomical long axis of the fourth ventricle. This positioning lessens the possibility of irritating or penetrating the brain stem. Moreover, as a more physiological solution, the shunt does not require a valve system. Because of these advantages, internal fourth ventricle-SSS shunting is proposed as a valid alternative to the "classic" fourth ventriculo-peritoneal shunt.

Surgical Management of Adult Hydrocephalus

“…The isolated fourth ventricle has been variously referred to as the trapped, sequestered, or occluded fourth ventricle and as an aspect of "double compartmental hydrocephalus" (25,32,39,72,86,122). It has garnered multiple publications for pediatric patients (24-26, 32, 35, 41, 50, 52, 53, 68, 72, 85, 103, 104, 107, 111) as well as adults (5,27,39,51,56,80,85,105,115,116).…”

Cranio-cervical decompression and expansile duroplasty for isolated fourth ventricle in a patient with Chiari II malformation

“…The authors felt that, although a lateral ventricle shunt may be required, in this case the avoidance of a fourth ventricular shunt may decrease complications and shunt revisions. Dollo et al 22 also described satisfactory results in a series of patients with entrapped fourth ventricle from several causes. A posterior fossa craniectomy was performed, along with dural patching with internal shunting -an internal tube inserted from the fourth ventricle to the spinal subarachnoid space.…”

The endoscopic trans-fourth ventricle aqueductoplasty and stent placement for the treatment of trapped fourth ventricle: Long-term results in a series of 18 consecutive patients

“…[15] Among these therapeutic options, the placement of a fourth ventricle shunt has been the most widely used therapy. [16,17] Shunt procedures can be effective but they present a high rate of malfunction [10] and complications mainly related to the risk of potential lesions to the floor of the fourth ventricle during the positioning of the catheter or, later, following a reduction in the size of the fourth ventricle. [11] Some authors proposed to introduce the catheter parallel to the fourth ventricle floor through a supratranstentorial approach under stereotactic guidance.…”