Peritoneal dialysis as a modality of renal replacement therapy for end-stage renal disease depends upon functional long-term access to the peritoneal cavity. Access is established by creating a controlled cutaneoperitoneal fistula with a catheter device that bridges the abdominal wall. After infectious complications, mechanical problems are the most common difficulties that threaten the functionality of the catheter. Mechanical problems include flow obstruction from blockage of the catheter tip by omentum, displacement of the intraperitoneal catheter segment to a position of poor drainage function, pericannular leakage of dialysate fluid through the abdominal wall, and hernia formation produced by abdominal wall weakening at the catheter insertion site.
Flow dysfunction produced by catheter obstruction or displacement generally follows 7–31% of catheter implantation procedures. Pericannular leaks and hernias complicate 5–27% of catheter insertions. The consequences of mechanical complications include additional operative procedures to remedy the problem, replacement of the catheter, or loss of the option of peritoneal dialysis as renal replacement therapy with permanent transfer to hemodialysis.
Shifting the catheter insertion site away from the abdominal midline to lateral placement through the body of the rectus muscle has reduced the incidence of pericannular leaks and hernias. Improved results for lateral placement are related to the physical characteristics of the abdominal wall in that lateral location: (i) two thick fascial layers, (ii) the thick body of the rectus muscle, and (iii) propensity for strong tissue ingrowth of anchoring polyester catheter cuffs from the rich muscle blood supply. Although generally improved with lateral placement, the incidence of pericannular leaks continues to range from 0–18%.
Varying degrees of oblique passage of the dialysis catheter through the abdominal wall in a craniocaudad direction have been recommended to maintain pelvic orientation of the catheter thereby reducing the risk of omental entrapment and catheter tip migration. Shorter abdominal wall tunneling was associated with a 9–11% incidence of catheter flow dysfunction while longer tunnels had an incidence rate of 0–3%. My own data revealed a 12.8% incidence of flow obstruction utilizing approximately a 45° oblique passage through the abdominal wall compared to 0.7% incidence associated with a 4–6 cm tunnel through the rectus muscle sheath (Crabtree, unpublished data).
The use of laparoscopically directed percutaneous methods of catheter insertion compared to the more invasive implantation by an open laparotomy incision is generally reported to reduce the incidence of flow dysfunction and pericannular leaks although, exceptions to these findings exist. Using visual guidance, the laparoscopic approach provides more precise intraperitoneal placement of the catheter and less tissue disruption from the standpoint that it constitutes a percutaneous puncture technique (see, for example, “A Laparoscopic Approach Under Local Anesthesia for Peritoneal Dialysis Access”, Crabtree, J. H. and Fishman, A., in Peritoneal Dialysis International, vol. 20 pp.757–765, incorporated herein by reference in its entirety).
Despite the general improvements associated with lateral placement, oblique abdominal wall tunneling, and laparoscopically directed percutaneous insertion, the outcomes remain extremely variable. The wide range of reported outcomes stems from a lack of uniformity in implantation tools and methodology. Devices generally used to perform percutaneous insertion and muscular tunneling are borrowed laparoscopic port cannulas that are oversized, possess dangerous trocar blades, and often require considerable modification that departs from the manner of intended use. The variety of available port devices leaves too much variability in application and thus reduces reproducibility and impedes establishing standard methodology for peritoneal dialysis catheter implantation. Abdominal wall tunneling by open dissection is not practical due to the considerable disruption of tissues required to create a passage of sufficient length. The identified problems with existing tools and methods include excessive tissue dissection that may result from open dissection, which increase the risk for pericannular leaks and hernias and limits the length of an abdominal wall tunnel. Additionally, there is an increase in the risk of hemorrhage, leaks, and hernias associated with utilizing trocar-tipped laparoscopic ports with cutting blades and/or oversized laparoscopic ports. Furthermore, laparoscopic ports utilizing an overlying plastic sleeve for radial expansion limit the length of the abdominal wall tunnel. The unsupported plastic sleeve tends to kink in the tissue tract when a guideneedle is removed and prevents safe insertion of a port cannula.
Valve assemblies found in most commercially available laparoscopic port devices and other cannula systems utilized in medicine require a valve assembly which comprises an apertured diaphragm in sequence with a non-return flap valve. Elastic properties of the apertured diaphragm create a tight fit around a component, such as a catheter, that is being advanced through the valve assembly, and the apertured diaphragm attempts to prevent backflow of an insulation gas, for example, through the valve assembly as the component passes through and opens the non-return flap valve. Ordinarily, components that are advanced through such valve assemblies are cylindrical in shape and nonporous and the aperture in the apertured diaphragm is round. The diameter of the aperture is constructed keeping in mind components, such as polyester catheter cuffs, for example, that are intended to pass through the valve assembly.
Physical irregularities of components, or portions thereof, being advanced through the valve mechanism may defeat valve competence. Exemplary irregularities that can defeat competence of the valve system include, but are not limited to, non-cylindrical shapes and porous materials, such as catheter cuffs. If the irregularity of a component surface exceeds the elastic capabilities of the apertured diaphragm to conform to that surface and maintain a seal, backflow of insulation gases will occur, leading to a collapse/deflation of a previously gas-expanded space, such as a peritoneal cavity, for instance.
Presently, approximately 12% of the end-stage renal disease population are on peritoneal dialysis. It is projected that this percentage will increase to 20–30% if proper utilization of cannula insertion and placement is practiced.
Clearly, there is a need for a dedicated apparatus specifically designed to provide improved and safe access to internal area/cavities/lumens, etc. of an organism, particularly the peritoneal cavity for implantation of peritoneal dialysis catheters. In particular applications, the apparatus should allow creation of a long oblique tunnel through the muscular abdominal wall without causing significant tissue disruption or risk of hemorrhage. For laparoscopic use, the apparatus should be capable of preserving pneumatic competence of a pneumoperitoneum created by gas insufflation. Desirable physical characteristics of an apparatus for creating access through an abdominal wall, include having minimal dimensions so as to provide passage of a catheter, for example. When utilized for access to the peritoneal cavity, the apparatus should have pneumatic competence for compatibility with laparoscopic techniques. Provided herein is an apparatus and associated methods of use capable of performing intended functions in a simple, accurate, reproducible, and expeditious fashion.
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