Fig. 10.1
Variations of buried catheter placement. Diagrams of different buried catheter configurations. The arrows point the area that is initially embedded. The different configurations are presternal exit sites (a), upper abdominal exit sites (b), straight Tenckhoff catheter (c), and swan-neck catheter (d) (Reprinted with permission Crabtree and Burchette [3])
The subcutaneous tunnels and exit sites can also be created in diverse anatomical regions (Fig. 10.1). Catheter extenders can allow to the catheters to be tunneled for longer distances to create presternal exit sites (Fig. 10.1a) [7]. Presternal exit sites may provide a lower infection rate and particularly useful in obese patients. Extenders can also be used to create exit sites in the upper abdomen (Fig. 10.1b).
At the time of externalization, an exit site is created at least 2–3 cm distal from the distal cuff. This is a routine, quick procedure that is done with local anesthesia. Under sterile technique, a small incision is made. Dissection of the subcutaneous adipose tissue is performed using a hemostat until the catheter is mobilized. Most catheters have developed a fibrin sheath along the exterior surface; careful removal of the fibrin sheath is performed with scissors and the catheter is then completely exteriorized. After removal of the distal suture and plug, an adapter set can be connected to the catheter tip in order to initiate dialysis.
Outcomes with Buried Catheters
Infections
Due to the above characteristics, it was predicted that subcutaneous peritoneal catheter embedding would decrease risk of infectious complications. In the initial description of the procedure, the authors performed a prospective evaluation of infections in all patients with buried catheters [1]. They found that the peritonitis rates were lower than historical controls but exit site infections appeared to occur at the same rate. The study sample included patients who performed a spike technique for exchanges and patients who used disconnect systems.
Despite that initial study, it is still unclear whether the Moncrief-Popovich technique decreases infectious complications. Two small, controlled trials have tested whether catheter burying decreases peritonitis. The first one randomized 30 patients to catheter placement with immediate externalization and 30 patients to catheters buried subcutaneously [8]. In the first group, the patients had a 6 week break-in period; in the buried catheter group, the catheters were externalized after 6 weeks. Half of the patients in each group used a Y-connector and half used the spike technique. The peritonitis-free interval was much longer in the group that received a buried catheter and used a Y-connector. This group had a peritonitis-free period of 120 patient-months while the group with a standard catheter using a Y-connector had a peritonitis-free interval of 26 patient-months. It should be noted that this study was small and had a low overall rate of peritonitis.
Another trial randomized patients at two separate hospitals to receive a buried or non-buried catheters [9]. Each center had a slightly different technique for catheter placement and catheter embedment. A total of 60 patients were included in this trial. Episodes of peritonitis were assessed at 6, 12, and 24 months. The group assigned to receive buried catheters did not have a statistically significant decrease in the time to first peritonitis episode. AS the other studies showed, there was no decrease in exit site infections. A meta-analysis pooled the results of these two studies and found that there was no reduced rate of peritonitis or exit site infections with buried catheters [10].
Catheter Damage
Since the catheter is not directly visualized during the externalization procedure, there is the risk of inadvertent damage to the catheter during the procedure. The needle used for local anesthesia can puncture the catheter as can the scalpel used for the skin incision. The rates of these complications are unclear but are likely quite low. In a retrospective review of 84 patients undergoing externalization, each complication happened in 1 patient [3]. Damage to the catheter tubing may not be a significant problem. Depending on the location of catheter tubing damage, a catheter revision can be performed without requiring further surgery.
Catheter Malfunction
One concern regarding catheter burial is a potential for catheter dysfunction after externalization. Since the catheters are typically placed before a patient requires dialysis, it is possible that the period of subcutaneous burying may last months or years. It is very difficult for practitioners to accurately predict when a patient may require dialysis. Since there is a general desire to avoid urgent dialysis, catheters are often placed well before the anticipated need for dialysis. However, it is possible that this strategy would increase risks for catheter failure since the catheter may migrate or intraluminal clots may form over the long duration.
Numerous studies have examined whether prolonged catheter burial negatively impacts catheter function. Results from a single-center study suggested that burial of single-cuff catheters was associated with increased mechanical complications [11]. The same center changed the catheter type to double-cuff catheters with a swan-neck. A retrospective analysis of outcomes with double-cuff catheters showed excellent long-term function [12]. In this study, the mean duration of catheter burial was approximately 40 days although some catheters were buried for more than 1 year. Ten percent of the catheters did not function immediately due to either fibrin plugs or omental wraps. However, all but one of these catheters were rendered functional by laparoscopic revision and ultimately 99.2% of catheters were useable. The duration of catheter embedment did not appear to predict long-term catheter function. Catheters that were embedded for longer periods had identical outcomes to catheters with short embedment duration (Fig. 10.2).
