Two-cannula insertion technique . (a) Localization of the skin incisions. Dashed line shows the entrance of the catheter through the rectus muscle and the peritoneum. (b) Creation of the subcutaneous tunnel with a trocar. (c) The end of the catheter is pulled out together with the cannula through the abdominal wall and subcutaneous tunnel until the inner cuff comes to lie just above the posterior sheath of the rectus abdominis muscle. (d) Final position of the catheter. From Emir H. Endoscopic Surgery for Peritoneal Dialysis Catheters in Children. In: Endoscopic Surgery in Infants and Children, Bax KMA et al., eds. 2008. Springer Berlin Heidelberg, Berlin, Heidelberg, pp 485–498. Reprinted with permission.
Once the appropriate catheter is chosen, it is inserted through the larger port, with the deep cuff positioned between the anterior and posterior rectus sheath in a downward and lateral subcutaneous configuration. This involves tunneling the catheter an additional 4–6 cm (depending on the size of the child), toward the midline pelvis, after it is seen above the posterior rectus sheath right before it enters the peritoneal cavity. This has been shown to prevent migration of the catheter tip and decrease leakage of fluid . This method does not require additional port placement and can be performed with or without an additional suture around the catheter at the anterior rectus sheath to further minimize leakage of fluid . If the inner cuff is fixed to the anterior rectus sheath, care should be taken that this suture is not cinched so tight it occludes the catheter. Suture fixation of catheter to the bladder, uterus, or pelvic sidewall has also been described as a method to decrease the risk for catheter tip migration. However, this technique requires additional port placement, may increase difficulty for future catheter removal, and may increase risk for hernia and adhesion development .
It is important to ensure that the inner cuff does not extend into the peritoneum. The superficial cuff should be approximately 2 cm from the exit site to decrease the risk of cuff extrusion, which is a known risk factor for exit site infection . Too short a distance will predispose to cuff extrusion, whereas too long a distance leads to formation of deep sinus tract, granulation tissue formation, and increased risk of tunnel infection. The catheter tip should be in the most dependent portion of the pelvis (Fig. 52.2), right above the bladder reflection, and anterior to the rectum in the rectovesical or rectouterine pouch. If the pelvic space is occluded with dense adhesions from a prior surgery or episode of peritonitis, the surgeon may elect to place the catheter over the liver below the right chest wall (Fig. 52.3).
Peritoneal dialysis catheter with pelvic positioning as seen on plain radiograph.
Peritoneal dialysis catheter with suprahepatic position noted on plain radiograph.
Catheter occlusion due to omental wrapping is more common in children than adults; therefore, routine omentectomy in smaller children and infants is performed. The omentum can be partially removed through the port using electrocautery or ligature. Although omentopexy is preferred to omentectomy in adults , the integrity of pediatric omentum poses a technical challenge in regard to suture fixation. Therefore, in smaller children and infants, a formal omentectomy is common. Laparoscopy also allows for repair of inguinal or ventral hernias if present. Comparative trials of open versus laparoscopic hernia repair in PD patients do not exist. However, most experts recommend fixing these defects at the time of surgery . If the child is in need of feeding access, a gastrostomy can be performed with two-point fixation to the fascia using absorbable suture. There is a slightly higher rate of infection in patients with gastrostomy tubes on PD, although independent from timing of gastrostomy placement . Finally, a renal biopsy can also be obtained under direct visualization with the biopsy needle after laparoscopic exposure of the kidney.
After removal of all the instruments and trocars, the fascia at the umbilicus is closed in two layers with an absorbable suture to prevent hernia development. The exit site should be round and small to allow for a snug fit within the surrounding skin. While some surgeons may elect to apply Dermabond (Ethicon Inc., Somerville, NJ, USA) at the exit site, there is clear evidence to suggest that sutures should not be placed at the exit site due to increased risk for bacterial colonization . Fibroblast ingrowth of the Dacron cuff will provide adequate anchorage of the catheter within 2–3 weeks. For patients who require dialysis shortly after catheter implantation, the usage of fibrin glue to the peritoneal cuff suture has been shown to prevent early dialysate leakage; however, this method does not decrease the risk for the development of peritonitis or exit site infection . The fibrin glue is applied around the internal cuff and down the tunnel between the inner and outer cuffs.
The silastic tubing of the catheter is attached to the infusion/drainage system using a titanium connector. This attachment is often prone to mechanical failure from slackening of the tubing, which can lead to eventual disconnection, leaving the patient at risk for bacterial entry with development of peritonitis. As a result, some advocate the use of a “lock-ring” device to further secure this connection . The distal portion of the catheter is attached to a universal male Luer Lock fitting “sealing cap.” This cap has a rubber stopper, with a self-sealing injection site for administering medication or drawing peritoneal dialysate samples. Once the dialysis catheter has been assembled, an intraoperative catheter trial using 10 cc/kg of dialysate with 1–2 units of heparin per mL or saline should be performed to ensure adequate inflow and outflow. This instillation and drainage cycle should be continued until the fluid is clear and demonstrates that at least 50 % of the instillate is returned. If at least half the fluid cannot be passively returned in the operating room, the catheter placement should be adjusted.
The catheter should be adequately secured to the abdominal wall to minimize mobility and traction injury. There are commercially available immobilization devices; however, a simple tape or gauze dressing is generally sufficient, as long as the catheter is securely anchored close to the exit site. Some oozing is to be expected; therefore, the exit site is initially dressed with several layers of sterile gauze or an ABD pad. An occlusive dressing should not be used, as these tend to trap fluid, which predisposes the exit site to bacterial growth and subsequent infection .
The initial postoperative dressing should not be changed more than once a week during the first 2 weeks, unless there is concern for bleeding or infection . Generally 2 weeks of healing time is given before the initiation of dialysis; however, if early dialysis is necessary, there are no data to suggest a substantial difference in minor versus major leaks in regard to the time of initiation or initial fluid volume [22–24].
Postoperative Care (Outcomes and Complications)
Although there has been vast improvement in catheter quality and surgical technique, the incidence of complications reported in the pediatric population remains relatively high. Basic laparoscopic insertion without using techniques to minimize catheter dysfunction results in similar rates of catheter malfunction as open insertion . Interestingly, advanced laparoscopic PD catheter insertion using lysis of adhesions, catheter fixation with rectus sheath tunneling, and omentopexy has the lowest reported rate of catheter dysfunction in adults, even in patients with prior abdominal surgery. The majority of pediatric studies available have described the use of the omentectomy during both open and laparoscopic catheter insertions; however, none of them have noted a decrease in reoperation for catheter dysfunction .
Catheter dysfunction is most often associated with occlusion from thrombosis or with mechanical failure due to kinking, compression, or migration of the catheter. A physical exam should be performed and plain radiographs obtained to rule out constipation. If negative, further studies such as catheterography may be helpful in delineating the underlying etiology. Catheter occlusions secondary to fibrin or blood clot can be managed with tissue plasminogen activator (TPA). Two milligrams of TPA reconstituted in 40 cc of normal saline, and instilled in the catheter for 1 h, resulted in restoration of patency in 57 % of catheters . Another technique described is the use of an endoscopic retrograde cholangiopancreatography cytology brush to manipulate a malfunctioning PD catheter, with subsequent flushing of the catheter with heparinized saline through the injection port to remove any clot or fibrin. The advantage of this method is the ability to also inject contrast through the injection port to confirm the patency of the catheter, while the brush remains within the lumen . If nonoperative treatments such as flushing, thrombolytics, and fluoroscopic manipulation are unsuccessful, then laparoscopy with catheter repositioning may be necessary (Fig. 52.4).