Lumboperitoneal Shunting

Introduction and Patient Selection

Lumboperitoneal (LP) shunting allows for extracranial management of hydrocephalus, cerebrospinal fluid (CSF) fistula, pseudomeningocele, and pseudotumor cerebri, thereby eliminating intracranial complications. LP shunts are also used to treat hydrocephalus in patients with slit-ventricle syndrome. Long-term complications of ventricular catheter obstruction by ependymal tissue in-growth and choroid plexus are also avoided; despite certain advantages over ventriculoperitoneal shunting, however, LP shunts are associated with a separate set of complications, including back pain and stiffness, arachnoiditis leading to hyperlordosis, scoliosis, radiculopathy, myelopathy, other lower extremity neurological sequelae, and symptomatic tonsillar herniation. Although the introduction of Silastic tubing has decreased the severity of arachnoiditis associated with polyethylene tubing, this complication has not been eliminated.

56.2 Preoperative Preparation

A thorough surgical history is essential in determining ideal intrathecal and peritoneal catheter placement. Anteroposterior (AP) and lateral lumbar spine films are obtained before the procedure for operative planning. Scoliosis and history of spinal surgery may increase the difficulty of passing a Tuohy needle into the thecal sac. A full-body 2% chlorhexidine gluconate bath is performed within 6 hours of the operation to reduce skin colonization by bacteria.

56.3 Operative Procedure

56.3.1 Preoperative Antibiotics and Positioning

Cefuroxime (1.5 g) is administered at least 30 minutes before making the incision. Sequential compression devices are applied before intubation in postpubescent patients. A beanbag is helpful in keeping the patient stable in the precarious lateral decubitus position. Ideally, this beanbag should be placed on the operating room table before transferring the patient. The patient is initially positioned supine for induction of anesthesia. The patient is then positioned in the lateral decubitus position, with side dependent on surgical history and desired location of peritoneal catheter implantation. A slight degree of flexion optimizes operative position for lumbar puncture. All pressure points are padded, including a roll immediately inferior to the axilla (axillary roll) and padding for elbows, wrists, knees, and ankles ( ▶ Fig. 56.1). The patient is then secured to the operating table by evacuating the beanbag and taping as necessary.

Fig. 56.1 All pressure points are padded, including a roll immediately inferior to the axilla (axillary roll), and padding for elbows, wrists, knees, and ankles.

56.3.2 Preparation and Draping

Meticulous preparation and draping of the surgical site is vital in any operation in which hardware is implanted to minimize surgical site infection. At our institution, a 2% chlorhexidine gluconate scrub is performed, widely, for at least 5 minutes, including the entire abdomen, lower chest, lumbar spine, and the strip of skin connecting the two operative sites. This area is then prepared in turn, with povidone iodine scrub (7.5%), isopropyl alcohol (70%), and povidone iodine paint (10%) in an aseptic manner. The povidone iodine paint is allowed to dry, and the incision is marked. The spinous processes are marked, and the lumbar incision spans two interspaces, usually L3–4 and L4–5. The LP shunt system is prepared by flushing the valve and catheters with normal saline. The lumbar and abdominal portions of the procedure may be performed simultaneously or sequentially.

56.3.3 Incisions, Abdominal Dissection, and Shunt Tunneling

After making the lumbar incision, dissection is carried down to the thoracolumbar fascia. The abdominal incision is dictated by the surgical history. A paramedian abdominal incision is ideal, between the rectus abdominis and lateral abdominal musculature, superior to the umbilicus. If dissection is performed too far laterally, the lateral abdominal muscles will be encountered. Dissection through them may cause bleeding and is generally more painful for the patient postoperatively. Dissection is carried down to the peritoneum through the subcutaneous fat, aponeuroses of the external oblique, internal oblique, and transverse abdominal muscle, and transversalis fascia to the parietal peritoneum. Often, the transversalis fascia is mistaken for the parietal peritoneum, resulting in supraperitoneal passage of the peritoneal catheter. This can be avoided by identifying the extraperitoneal fat, which lies between the transversalis fascia and the parietal peritoneum. The shunt passer is used to create a subcutaneous tract from the lumbar incision, through the subcutaneous pocket, and to the peritoneal incision ( ▶ Fig. 56.2).