In Reply: Lumbar Puncture or External Ventricular Drainage as Initial Treatment for Acute Hydrocephalus in Aneurysmal Subarachnoid Hemorrhage–A 2-Center Cohort Study

To the Editor: We appreciate the interest in our manuscript on lumbar puncture as initial treatment of acute hydrocephalus in patients with subarachnoid hemorrhage,1 and we read with interest the comments written by Drs. Palermo and Sturiale2 in their letter to the editor. The points raised by the authors are important considerations. We agree with the authors that the reduced rate of ventriculoperitoneal shunt implantation in patients initially treated with lumbar puncture may not be explained by the drainage site only. We share their hypothesis that the smaller volume of drainage and the single or intermittent drainage play a role as well. Compared with lumbar drains with a controlled, intermittent drainage rate (eg, 5 mL/h, as applied in the EARLYDRAIN trial),3 single or repeated lumbar punctures (up to 3) result in a significantly lower total drainage volume. As ventriculoperitoneal shunt dependency may be associated with the continuous draining or cumulative volume of drained cerebrospinal fluid,4 reduced drainage could help to avoid overdrainage in certain patients. However, in other patients, hydrocephalus may not be sufficiently treated by lumbar puncture alone. The authors correctly comment that although there was a trend toward better outcomes in patients initially treated with lumbar puncture, the difference was not statistically significant. This may in part be explained by small numbers of patients or by the downsides of lumbar puncture. Indeed, smaller volumes drained with lumbar puncture may lead to lower blood clearance and thereby a higher risk of delayed cerebral ischemia. An advantage of lumbar puncture is a lower risk of complications, including infections. Thus, the key challenge remains identifying those patients for whom 1 to 3 lumbar punctures are sufficient to resolve hydrocephalus and improve clinical outcome. To optimize patient selection—specifically, to determine which patients benefit from lumbar puncture alone and which require a lumbar drain, external ventricular drain, or combined approach—as well as to understand in which outcome domains treatment strategies differ, randomized trials are needed. The authors and we agree on this point too.