Letter: Experience With Ventriculoperitoneal and Lumboperitoneal Shunting for the Treatment of Idiopathic Intracranial Hypertension: A Single Institution Series

Abstract

To the Editor: We read with great interest the article titled “Experience With Ventriculoperitoneal and Lumboperitoneal Shunting for the Treatment of Idiopathic Intracranial Hypertension: A Single Institution Series” by Sweid and collegues,1 published recently in the Operative Neurosurgery journal. We appreciate the authors for their work on this key issue in the management of idiopathic intracranial hypertension (IIH). This retrospective study includes one of the largest cohorts of patients diagnosed with IIH undergoing cerebrospinal fluid (CSF) diversion. The authors have compared 2 modalities of CSF diversion, ventriculoperitoneal shunt (VPS) and lumboperitoneal shunt (LPS), for the rate of revisions, malfunction, infection, and complications. A statistically significant association between shunt revisions and increasing age was noted. The proportion of shunt malfunction with LPS was significantly higher compared to the VPS. The revision rate of LPS is higher (60%-85%) when compared to VPS, owing to shunt malfunction in the majority of the cases. The risk of overdrainage is also high with LPS apart from the rare incidence of acquired Chiari type I following LPS.2 Here we like to include 2 important technical aspects related to the navigation-guided VPS: the type of navigation used; the choice of the entry point for ventriculostomy. The accurate placement of the tip of the ventricular catheter in VPS is one of the critical aspects determining the shunt functionality. Therefore, stereotactic-guided placement of ventriculostomy catheters is favored especially in the presence of normal or slit-like ventricles. The authors used Medtronic Stealth Station for the navigation-guided placement of the ventriculostomy catheter in the frontal horn. This was accomplished through a precoronal burr hole. It is evident from the brief description of their technique that the authors have used the Optical method of navigation. The disadvantage of this type of navigation is the need for rigid head fixation. The other disadvantage relates to the subcutaneous tunneling connecting the cranial and abdominal incisions. The tunneling becomes challenging due to the rigid head fixation leading to difficulty in manipulating the head and neck. In these circumstances, the need for an additional incision while passing the tunneler becomes necessary, especially when a precoronal ventriculostomy point is chosen. This might also compromise the sterility during the surgery owing to the increase in number of incisions, although the rates of infection as observed by the authors are comparable to the standard literature. Hence, the electromagnetic method of navigation available with the Medtronic Stealth Station system called the “AxiEM” is preferred. In this technique, the head is free instead of rigid fixation. A digital reference frame (DRF) is wrapped on the forehead, which acts as a fixed reference tracked by the magnet. Using this technique, the ventriculostomy entry point may be planned in the parietooccipital region. The shunt surgery may be performed in a standard fashion, including the tunneling procedure, as the head and neck are free for maneuvering, without compromising the accuracy. The literature is replete with studies performing VPS using a magnetic method of navigation with excellent accuracy even in slit-like ventricles accompanying IIH.3 Recently, we described the technique of robotic-guided VPS through the parietooccipital entry point with similar accuracy.4 The accuracy of robotic-guided procedures in technically demanding procedures like deep brain stimulation, lesioning of hypothalamic hamartomas, and even bilateral cingulotomies as part of psychiatric surgery and recently performed radiofrequency ablative hemispherotomy is also well documented in the literature.5-9 Therefore, in patients presenting with severe headache and rapidly diminishing vision, CSF diversion becomes a mandatory emergency procedure, although other methods like optic