The primary goal of treatment for patients with LH is to alleviate symptoms caused by enlarging, loculated CSF compartments. Ideally, this goal is accomplished in a way that maximizes communication between CSF compartments and enables adequate CSF circulation with one shunt catheter or, occasionally, without any shunt catheters. Fenestration procedures enable fewer shunt catheters and therefore fewer opportunities for obstruction, disconnection, and infection. Moreover, fewer shunt catheters enable easier identification of the source of presenting signs and symptoms in the setting of a symptomatic patient with a shunt malfunction. Fenestration can usually be accomplished endoscopically, as described below, but craniotomy is an option for patients with thick membranes and very complicated anatomy. Many patients with LH will require several or many procedures over the course of their childhood, which will include shunting procedures and fenestration procedures, either open or endoscopic. Given the complexity of LH, treatment options must be individualized and carefully planned to minimize both complications and the requirement for additional treatments [27].

Most patients with LH, regardless of fenestration procedures, will require a CSF diverting shunt. The rate of shunt malfunction in patients with LH is very high. Nida and Haines [16] and Lewis et al. [15] reported a median of 2.75 and 3.04 shunt revisions per year, respectively, in their series. Prior to the advent of modern neuroendoscopy, many patients with LH had multiple shunt catheters placed into different loculated compartments. When patients with multiple shunt catheters present with new symptoms, it is often difficult to assess exactly what needs to be done surgically to alleviate these symptoms. Many patients with LH are significantly developmentally delayed, making diagnosis of clinically significant shunt malfunction challenging at baseline, and shunt taps in the setting of multiple shunt systems can be practically difficult and misleading [22]. Moreover, shunt infections require multiple incisions for removal of all potentially colonized hardware. Fenestration of loculated CSF compartments via endoscopic techniques, open craniotomy, or a combination of these to reduce the number of required shunt catheters as much as possible is currently recommended.

Recent advances in endoscopy such as improvements in optic design, bright cold-light sources, and small-diameter rigid and flexible endoscopes have expanded the use of neuroendoscopy in the management of intraventricular pathology and LH [26]. Many authors have reported that endoscopic procedures may reduce shunt revision rates in patients with LH [6, 15, 25, 26]. The main advantages of endoscopic fenestration over craniotomy include its limited invasiveness as well as a shorter recovery period [15]. Carefully planned endosopic approaches enable wide access to loculated CSF compartments bilaterally via a single small incision and burr hole [24]. Fenestrations should be as wide as possible to ensure durability. When fenestrations are small, there is a high incidence of early reclosure due to the low-pressure differential across cyst walls and the inflammatory origin of the disease [26, 27]. Fenestrations can be enlarged with forceps, scissors, Fogarty balloons, or a combination of these instruments [27].

When performing endoscopic fenestrations, the surgeon must carefully evaluate structures on the other side of the wall being fenestrated, as it can be easy to lose anatomic orientation in these sometimes challenging cases. Once the fenestration has been completed, the endoscope should be advanced through it to inspect structures beyond the fenestrated wall. Challenges of endoscopic procedures in the management of LH include the distorted anatomy as a result of prior hemorrhages, infections, or congenital malformations. Shifts in the anatomy as a result of the cyst fenestration and CSF drainage can also be challenging as cysts typically lack landmarks. Therefore, the integration of neuronavigation to aid in preoperative planning and intraoperative orientation and the use of navigated endoscopy and intraoperative MR imaging have become increasingly popular [19, 24]. Ultrasound can also be utilized in real time to aid with endoscopic fenestrations, especially in infants with open fontanelles. While ultrasound image resolution is less than MRI, ultrasound has the advantage of providing real-time special orientation of loculated CSF compartments.

Despite technical success with endoscopic fenestrations, the majority of patients with LH require repeat endoscopic fenestrations and/or shunting procedures. Postoperative images may demonstrate decrease in some CSF compartments but increased size of other compartments and/or new subdural CSF collections (Fig. 23.2a, b).

There are limited published reports describing craniotomy for fenestration of intraventricular septations in the management of LH [16, 20, 22, 27]. The operating microscope enables a wider and deeper field of view than current endoscopic technology and allows for a broader range of microsurgical instruments to be utilized. Thus, craniotomy for microscopic fenestration may facilitate better visualization of compartments and membranes and wider fenestration of septations. Bleeding is much easier to control with standard techniques under the operating microscope than with endoscopy, during which a small amount of bleeding can significantly hamper visualization. Disadvantages of this technique include a larger skin incision, requirement for a craniotomy, and longer operating room times. In many instances the craniotomy is performed simultaneously with a shunt revision, and only a small extension of the existing shunt incision is typically required [22]. In a prior report of craniotomy for fenestration of LH [22], there were no new neurologic deficits as a consequence of the procedure. This, however, can be difficult to truly assess since the majority of patients in the series were severely developmentally delayed.