LAUSR

There is a controversial discussion on what site to use for ventricular-peritoneal shunt placement after treatment of hydrocephalus via an extraventricular drain. It is an almost daily concern, whether to use the same ventricle site in which the EVD had been previously placed or to insert the drain on the contralateral side. Especially in patients with subarachnoid hemorrhage, the progression from acute to chronic hydrocephalus is very frequently observed (about 23% of patients with SAH present with an acute hydrocephalus and about 18% require a shunt for the long term treatment of a chronic hydrocephalus) [1, 4–6]. At a first glance different hypotheses supporting an ipsior contralateral approach of shunt placement come to mind. It seems plausible that using the ipsilateral site is associated with a higher risk of infectious complications. A bacterial colonization of the drainage tube that constitutes a connection between the intracranial and extracranial environment, as well as of the superficial wound itself may take place. Also the time period between EVD placement and shunt implantation can influence the risk of infection. All this supports a contralateral approach. On the other hand, however, benefits from using the existing ventriculostomy may be a reduced perioperative bleeding risk as well as a shorter operating time. Two burrholes and two approaches most likely incorporate a twofold higher risk of approach-related complications. Current data by Ilic et al. published in this edition’s Acta Neurochirurgica compares the two approaches by investigating the outcome and complication rate of 164 patients with SAH and secondary acute hydrocephalus that required shunt implantation. One hundred fifteen patients underwent surgery at the ipsilateral site, whereas 49 patients had the implantation on the contralateral side. In this cohort no statistically significant difference concerning infection (5% ipsilateral vs. 10% contralateral) and perioperative hemorrhage could be demonstrated (3.5% ipsilateral vs. 2.0% contralateral). Two previously published studies investigated the influence which implantation site was chosen. Rammos et al. presented data of 80 patients evaluating complications of solely using the ipsilateral implementation site, which showed no shunt-related infection at all. However, antibiotic impregnated catheters for both EVD and shunt were used [8]. In the largest cohort investigating 523 patients with acute hydrocephalus due to either SAH or AV-malformation-related bleeding, 88.7% of patients underwent shunt conversion ipsilaterally and 11.3% contralaterally. Again no significant difference concerning the infection rate (ipsilateral 8.5% vs. contralateral 6.5%) was demonstrated. The rate of shunt-related hemorrhage was found to be slightly higher in implantations on the contralateral side (1.7% vs 0.0%, p = 0.006). Here also antibiotic impregnated catheters were used for the EVD but not for the shunt systems [3]. In the cohorts by Ilic et al. and Chalouhi et al., the neurosurgeons individually decided onwhich side to use. One of the most important guiding factors aiding this decision was the appearance and condition of the wound. In cases where the wound appearance was suspicious for infection or delayed healing, the contralateral side was used [3]. The time period between EVD placement and shunt implantation differed considerably in the abovementioned studies. Ilic at al. had the longest time interval of 46/50 days, compared with Rammos et al. with 12.5/12.7 days and This article is part of the Topical Collection on Vascular Neurosurgery Aneurysm