gms | German Medical Science

Objective: Lumboperitoneal (LP) shunts were inaugurated by Ferguson in 1898, in 1967 Murtagh introduced the use of Touhy-canulas in catheter placement. These shunts are commonly used in pseudotumor cerebri, therapy-refractory CSF fistulas and selected hydrocephali, but show three specific problems: 1. Especially in children irritations of the cauda-roots by the spinal catheter with potential of pareses and development of scoliosis may occur. 2. The thin catheters (ED/ID usually 1.3/0.8 mm) are at high risk for kinking and rupture. 3. Implanted differential pressure (DP) valves lead often to symptomatic overdrainage. This may lead to herniation of the cerebellar tonsils, first described as “acquired Chiari” (a.C.) by Welch in 1981, up to now themathized in 215 papers. Classical series of Chumas and Payner (93/94) counted a.C. in 70%, more recent papers in 10-20%. A.C. may induce Chiari symptoms and syringomyelia up to cerebral herniation. Even lethal cases are published (Chumas 92, Aoki 90). The disease may be reversible after explanation or conversion to a ventricular shunt. Though LP-implantations are simplier and faster compared to VP-shunts and the mortality in lumbar is 0.3% vs. 0.9% in ventricular shunts (932 pseudotumor-cerebri-cases, Curry 05), many neurosurgeons avoid lumbar derivation due to the above-mentioned problems.

Method: We reevaluated 43 LP- and 26 other spinal shunts between 1984 and 2010 looking for acquired Chiari. Indications were in 41.9% pseudotumor cerebri, in 32.6% CSF fistulas, 11.6% had posthemorrhagic hydrocephali, 13.9% had other indications.

Results: Four of 43 patients with simple DP-valves developed an acquired Chiari (9.3%). In contrast, none of the 26 patients with gravitational (g) valves – preferably Miethke GAV 5/30 cm H₂O or Medium Hakim ball-valves in combination with ShuntAssistant 25 cm H₂O – showed signs of tonsillar herniation.

Conclusions: G-valves in LP-shunts prevent from spinal overdrainage, thus decreasing the incidence of headaches in vertical position and eliminating the risk of acquired Chiari. In patients with symptomatic overdrainage or even tonsillar herniation additionally implanted g-valves can solve the problems avoiding further complicated course and possible revisions. Precondition for success is a meticulous vertical implantation and adaptation of the g-valve resistance to body length and weight. – Introducing kinking-resistant lumbar catheters – up to now the last unsolved problem – could lead to increasing numbers of lumbar shunting.