**4. Surgical technique**

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where the excess CSF can freely drain into the peritoneal cavity [4, 8].

**3. Ventriculoperitoneal shunt: challenges**

nal, and lumboperitoneal [7].

**2. Ventriculoperitoneal shunt**

Other surgical treatment options include third ventriculostomies and alternative shunt types [6] such as ventriculoatrial (VA), ventriculopleural, ventriculocister-

VP shunts are comprised of a proximal inflow catheter, reservoir, valve mechanism, and a distal outflow catheter. The proximal catheter generally lies in the trigone of the lateral ventricle; however it can be inserted in the frontal horn if it follows an internalization of an external ventricular drain. The proximal catheter leads into the reservoir, which contains a small collection of CSF used for samples or to obtain pressure measurements. A retro-auricular unidirectional valve follows the reservoir and is responsible for controlling the flow of CSF into the distal catheter. The distal catheter then travels subcutaneously from the valve into the right upper abdominal quadrant

Although a commonly relied upon procedure to treat hydrocephalus, VP shunts are not without complications and failures. VP shunts are subject to a variety of complications of mechanical, functional, and infectious nature [6]. Mechanical complications consist of complications inhibiting the shunt from functioning, including shunt migration, obstruction, malpositioning, disconnection, and fracture. Contrarily, functional complications involve improperly functioning shunts such as overdrainage or underdrainage [6]. Finally, shunts are subject to various infections, the majority arising from normal skin flora and occurring within 30 days of surgery [3]. Current studies suggest an overall infection rate of 8.4% and a shunt failure rate, defined as a catheter-related problem necessitating surgical intervention [9], of 51.4% [10]. It has been shown that patients require 2–3 surgical revisions on average due to shunt failures in the 20 years after the original shunt placement [8], with the majority of shunt revisions occurring in the first 6–12 months [4, 8]. Specifically, 25–30% of all shunt revisions result from distal peritoneal catheter failure [5, 11, 12], such as preperitoneal placement, obstruction due to adhesions or pseudocysts, and malabsorption with secondary ascites [12].

With time, the frequent revision rates and complications have provoked multiple changes and advancements in both VP shunt equipment, including the catheters and valve mechanisms [9, 13], as well as the surgical procedure itself [9]. Traditionally, VP shunts have been inserted using mini-laparotomy, although recently, a neuronavigated laparoscopically assisted approach has become a more commonly accepted surgical technique [9, 14]. Multiple studies have demonstrated that relative to the mini-laparotomy technique, a laparoscopically assisted approach has a shorter operative time and length of stay in the hospital, a decreased distal shunt failure rate [4, 9, 14], and a decreased risk of visceral injury [10]. Laparoscopy has also been shown to offer favorable outcomes with smaller incisions leading to reduced post-operative pain [11], faster mobilization and a preferred cosmetic appearance [5]. Many of the proposed benefits associated with laparoscopicassisted VP shunts are a direct result of the increased visualization offered by laparoscopy. Laparoscopy allows for the verification of accurate peritoneal placement of the distal catheter as well as the proper functioning of the shunt by observing CSF outflow [5]. Laparoscopy can also be used to perform adhesiolysis, useful in the presence of excess adhesions, often found in patients who have undergone previous

**68**

The procedure is done under general anesthesia, in the supine position with the head turned 30–45° toward the left, as right trigone is favored for the insertion of the ventricular catheter. The left upper limb is in abduction with the shoulder at 90°, and the right upper limb is tucked against the body. First generation cephalosporin is administered 30–60 minutes before incision. The neuronavigation magnetic system (Axiem, on Stealth by Medtronic) is used with 3D reconstruction of preoperative brain CT scan. Entry point, trajectory and length of insertion are defined on the navigation system. A Foley catheter is not used, as the risk of bladder injury is lowered by laparoscopic approach, which in turn reduces the post-operative UTI risk. A retro-auricular shaving for horizontal 2 cm incision or question mark incision is done. Scrubbing with chlorhexedine 2% is done at the cranial level and over the neck, chest and abdomen. Draping from the scalp to the pubic level is done in sterile fashion.

#### **4.1 Tunneling of the peritoneal catheter**

Starting at the scalp, an incision is made, dissection of the galea until reaching the entry point. Dissection of the subcutaneous cranio-cervical tissue is done.

A 60–90 cm passer is used from the scalp to the right upper quadrant (RUQ ). The peritoneal catheter is tunneled through the passer and 5 mm incision is done at the RUQ. An anti-siphon programmable or pre-fixed pressure valve is connected to the peritoneal catheter.

#### **4.2 Placement of ventricular catheter**

The ventricular catheter is inserted using the navigation stylet until reaching the body of the right lateral ventricle. CSF is drained and a sample for culture is routinely sent. Ventricular catheter is connected to the valve and CSF flow through the valve to the peritoneal catheter is observed before peritoneal insertion of the catheter.

#### **4.3 Placement of abdominal catheter**

Laparoscopic approach to the peritoneum is done by the general surgeon. A supra-umbilical, longitudinal incision is incised through skin with the scalpel blade. The incision may be altered due to previous surgery and concern for adhesions. Generally, we will go through old incisions using the supra-umbilical technique, but an infra-umbilical or epigastric open technique can be used as well. The fascia is elevated between two Kocher instruments and divided with scalpel blade. The peritoneum is divided between two snap instruments with scalpel blade. A finger is inserted into the abdomen to ensure adhesions are clear of the undersurface of the abdominal wall. Previous surgery and/or adhesions are not a contra-indication to this technique. Adhesions may be taken down carefully from the undersurface of the abdominal wall to allow placement of the laparoscopic balloon port. A 5–10 mm laparoscopic balloon port is placed intra-abdominally and the abdomen insufflated.

We maintain medium flow (20–30 L/min) and pressures (15 mmHg) for all cases. A 5 mm, 30-degree camera is inserted into the abdomen and used to visualize the undersurface of the abdominal wall. Placement of the catheter was generally in the RUQ but was also placed in left upper quadrant (LUQ ) depending on adhesions from previous surgeries or due to the presence of previously placed shunts. At times we did navigate through heavy adhesions to guide the catheter placement but did not ever need to take down adhesions laparoscopically or add additional trocars for the catheter placement.

After the laparoscopic approach to the peritoneum is done, we approach the abdomen by a puncture using an introducer sheath and dilator (Arrow®). The catheter and CSF flow is observed in the peritoneal cavity. Once the shunt is placed the sheath is removed and skin closed with 4-0 subcuticular monocryl stitch.

After final satisfactory inspection of the abdomen is desufflated and the camera and laparoscopic balloon port removed. Fascia is closed with a purse-string 0-PDS suture. Skin is closed with a 4-0 subcuticular monocryl stitch. Incisions are infiltrated with 0.5% Marcaine with epinephrine. Steristrips and dry dressings are applied.

Following the completion of the laparoscopic portion of the procedure, the scalp closure is done in 2 layers and the entry point to the abdomen is closed in 1 layer.

Patient is awakened extubated and transferred to recovery room. Once fully awake, patient is transferred to the floor; diet is started at 6 hours post operatively in addition to increasing activity.
