Fig. 9.1
Intraperitoneal and extraperitoneal PD catheter designs (Courtesy of W. Kirt Nichols, MD)
- A.
Tenckhoff Catheters:
Makeup: These catheters are made up of Silicone rubber with one or two polyester (Dacron) 1 cm long cuffs.
Dimensions: Internal diameter is 2.6 mm while external diameter is 5 mm. The lengths of the segments are: Intra-peritoneal 15 cm, intramural (Inter-cuff) 5–7 cm and external 16 cm.
The intra-peritoneal part has several perforations along with the distal portion of the catheter.
Coiled vs Straight Tenckhoff catheters: The coiled Tenckhoff catheters are preferred over straight ones due to decreased “jet-effect” and pressure discomfort during filling and emptying.
Both coiled and straight Tenckhoff catheters are provided with a barium-impregnated radiopaque stripe to assist in radiological visualization of the catheter.
- B.
Swan- neck peritoneal catheters:
Twardowaski et al. in 1993 [17], showed the complications associated with peritoneal dialysis catheters could be lowered if the double cuffed catheters were implanted through the belly of the rectus muscle and with both internal and skin exits of the tunnel directed downwards. But, resulting arcuate tunnel can lead to extrusion of the external cuff in straight catheters due to shape memory. Swan-neck catheters have a permanent bend between the two cuffs, which make them perfect match for the arcuate tunnel to avoid extrusion. With downward facing internal and skin exits, the rate of infections can be significantly decreased. Further, adding a coiled intra-peritoneal portion can reduce the pain and pressure discomfort with infusion. The intra-peritoneal segment in all swan neck catheters is 34 cm from the bead to the tip of the coil.
Features of Swan-Neck catheters | Advantages of specific features |
|---|---|
1. Downwards Exit | Prevents Exit/Tunnel infections |
2. Coiled intra-peritoneal tip | Prevents Infusion/pressure pain |
3. Insertion through rectus muscle | Avoid peri-catheter leak due to excellent tissue ingrowth |
4. Downward intraperitoneal entrance | Prevents intraperitoneal tip migration |
5. Permanent bend between cuffs | Prevents external cuff extrusion |
Swan-Neck Presternal Catheters
The chest is a sturdy structure with minimal motion. A catheter exit site on the chest has the advantage of: Minimal wall movement, decreasing chances of trauma and contamination due to the piston like movement of the superficial cuff in the abdominal wall. Twardowaski and Nichols in 1992 and 1993 modified Swan-neck peritoneal catheters to have an exit on the chest with preservation of all the advantages of the Swan-neck peritoneal coiled catheters [12]. The Swan-neck pre-sternal catheter is composed of two silicone rubber tubes, which are cut to an appropriate length and connected end to end at the time of implantation: (Figs. 9.2 and 9.3). The great flexibility permitted by cutting the upper portion to length in the operating room means that the catheter exit site can actually be tailored to come out anywhere on the upper abdomen or lower chest as the patient and surgeon determine to be the best.
Fig. 9.2
Presternal peritoneal dilaysis catheter system including curl cath, extension piece and titanium connector (Courtesy of W. Kirt Nichols, MD)
Fig. 9.3
Pre-sternal -Missouri Swan Neck Catheter insertion into peritoneal cavity with close-up of titanium connector joining the two portions of catheter (Courtesy of W. Kirt Nichols, MD)
- A.
Abdominal Tube (Lower Portion):
The abdominal tube constitutes the intra-peritoneal catheter segment and a part of the intramural segment. This portion is identical to the Swan-neck abdominal catheter with exception of no bend and absence of the second cuff. The proximal end of the lower tube is straight with a redundant length, to be trimmed to the patient’s size at the time of implantation. The two components are connected with a titanium connector.
- B.
Chest tube (Upper Portion):
The chest portion of the tube constitutes the remaining part of the intramural segment and the external catheter segment. This portion has two porous Dacron cuffs, a superficial and middle cuff, spread 5 cm apart. The tube between the cuffs has a permanent bent section defining an arc angle of 180°. The distal lumen of the upper tube communicates with the proximal lumen of the lower tube through the titanium connector. The tubing grip of the connector is strong enough to avoid spontaneous separation of the tubes.
Advantages of Swan-Neck Pre-sternal Catheters
More than 20 years after the introduction of pre-sternal catheters, they tend to perform better as compared to the abdominal catheters with respect to removal due to exit and tunnel infections, peritonitis and overall survival [18, 19]. Patients with ostomies and obesity also do better with the chest catheters as compared to the abdominal catheters. Patient acceptance of the pre-sternal exit site is also good due to psychological and body image reasons. A chest exit location allows a tub bath without the risk of contamination. Pre-sternal catheters are also very advantageous in small children because of the greater distance from diapers and are subjected to lesser trauma during crawling and with falls.
Advantages of pre-sternal Swan-neck catheters |
|---|
1. Decreased risk of exit site infection |
2. Decreased risk of peritonitis |
3. Decreased risk of intra-peritoneal tip migration |
4. Decreased risk of peri-catheter leaks |
5. Better Psychosocial acceptance of the catheter |
Patient Selection
The success of the peritoneal dialysis is dependent of the correct patient selection. There are only a few absolute contraindications to the initiation of peritoneal dialysis which include: Active peritoneal infections (Diverticulitis or severe inflammatory bowel disease, etc.) or uncorrectable pleuo-peritoneal connections. A majority of the relative contraindications are usually dependent on the institutional experience with peritoneal dialysis.
A majority of nephrologists now agree that the patients, if appropriate, should be offered peritoneal dialysis at the start of the dialysis in order to better preserve the residual renal function. Over time, concerns have been expressed regarding PD-dependent negative impact on survival but it has been also shown that PD provides survival advantage at least during the first few years being on dialysis. Frequent patient evaluation is essential to allow prompt adjustments in the dialysis prescription and modality when required. Important patient-related factors while considering PD include: Diabetes, large and small body size, peritoneal membrane transport status, age group and socioeconomic status.
Once the patient has been determined to have the functional capability for performing peritoneal dialysis, the relative surgical contraindications must be considered. The preoperative evaluation of a patient also includes a thorough surgical history and physical examination. Previous open abdominal operations are not a contraindication to PD catheter placement but adhesions formed to the anterior abdominal wall can increase the risk of abdominal access.
Generally, PD catheters do not require a long time to mature as compared to primary AV-fistulas. Typically from placement to training requires 2–3 weeks to before starting peritoneal dialysis.
Advantages of peritoneal dialysis |
|---|
1. Preservation of residual renal function |
2. Increased Survival in first 2 years |
3. Patients with Coronary artery disease |
4. Patients with advance liver cirrhosis and recurrent ascites |
5. More patient mobility |
6. More economical |
7. Decreased rate of infections |
Pre-sternal catheters have an advantage over abdominal catheters as they can be used in patients with obesity, with a history of multiple abdominal operations, or ostomies. Many of our patients find the “pre-sternal” location preferable for reasons of hygiene and general care of the catheter, especially those patients with urostomies, cololostomies, and those with marked obesity.
Indications of pre-sternal dialysis catheter placement |
|---|
1. Obese patients (Less Subcutaneous tissue on chest wall in obese patients) |
2. Previous multiple abdominal operations |
3. Patients with ostomies |
4. Diapered children |
Surgical Technique
Pre-sternal PD catheters may be placed using traditional open surgical placement and laparoscopic techniques. In this section we will discuss the technique as well significant merits associated with each of these insertion methods.
Open Insertion Technique
Open surgical placement of peritoneal dialysis catheters such as Tenckoff catheters or Swan-Neck catheters should begin with a standing evaluation of the patient noting the belt line as well as marking with indelible ink identification of this landmark which is not obvious when the patient is supine on the operating room table, location of abdominal scars, hernias and ostomies. We also advocate supine examination with the patient lifting their head off the table. This maneuver, much like in preoperative marking for ostomy sites, allows easier identification of the rectus musculature. Proper identification of the rectus ensures that the incision will allow trans-rectus placement of the catheter an occasional problem in those with diastasis recti (Fig. 9.4). This has been shown to decrease not only peri-catheter site leakage, but also catheter tract infections which can predispose towards peritonitis by allowing better tissue ingrowth into the cuffs [19].
Fig. 9.4
Examination of abdomen giving consideration for old scars, location of rectus (diastasis), ostomies, belt line (Courtesy of W. Kirt Nichols, MD)
The patient is positioned supine. Arm positioning is surgeon dependent, however, we find it easier to perform the pre-sternal tunneling and chest incision with the patient’s arms tucked into the side and padded. After induction of appropriate anesthesia, 3–5 centimeter (cm) incisions is marked, usually lateral to the approximate location of inferior epigastric vessels but centered over the left rectus muscle, and the presternal incision and path of the catheter is also marked (Fig. 9.5). Next, an incision is made. Electrocautery is used to deepen incision and self-retaining retractors such as Weitlaner, are used to facilitate exposure. Care should be taken to have meticulous hemostasis as post-operative hematoma potentially becomes a source of catheter infection. The incision is deepened to the anterior rectus sheath which is opened transversely.
