Reconstruction of complex defects
Complex wound defects in the perineum are defined as wounds with a large volume loss in the pelvis, or where there is a need for a partial or total reconstruction of the vagina (6). In larger skin and vaginal defects without any large volume defect in the pelvis, local skin flaps consisting of skin and subcutaneous tissue from the pudendal and gluteal regions will be good alternatives for reconstruction. With a suitable wound defect and well-planned incisions, the scars can be concealed in the gluteal fold (10–12). If the patient has a limited volume defect that needs reconstruction with non-irradiated tissue, a flap of the gracilis muscle can be a good alternative (13, 14). Via a skin incision in the thigh, this muscle can be dissected from where it is attached by the medial tibial condyle and moved under the skin into the wound cavity. If a skin defect also needs to be covered in the same intervention, the muscle can be harvested with the overlying skin.
Cancer surgery in the pelvis can be associated with large volume defects. Depending on the underlying cancer, it could be relevant to remove not only skin in the perineum, but also the anus, rectum and/or urinary bladder, the uterus, ovaries and parts or all of the vagina. The patients have often received pre-operative radiotherapy in the area to be reconstructed. There could be a need to fill volume defects in the pelvis, restore skin coverage in the perineum and reconstruct the vagina partly or in full with non-irradiated tissue.
A frequently used method for reconstructing this type of defect is a pedicled flap made from one of the muscle bellies of the rectus abdominis muscle, with or without the overlying skin (vertical rectus abdominis myocutaneous flap, VRAM flap). The muscle can cover a large volume defect in the pelvis, and the skin island can be used both in the reconstruction of a skin defect in the perineum and for partial or full reconstruction of the vagina (15). Circulation of the flap is dependent on the inferior epigastric artery not being damaged from previous procedures and the patient not having previously undergone surgery in which the rectus abdominis muscle has been severed, for example open biliary tract surgery or open liver surgery. The flap is harvested by drawing up a skin island corresponding to the perineal and vaginal defect over the cranial part of the muscle. The skin is incised down to the muscle, while the blood vessels to the skin from the underlying muscle are preserved. The muscle is severed cranially where it is attached to the costal arch and brought down into the pelvis. The skin island is drawn through the perineum and used to reconstruct the perineum and the posterior vaginal wall or to construct a neo-vagina (16) (Figure 3).
After reconstruction of the perineum, it is important to avoid pressure on the reconstructed area. Since there is always reduced blood supply to the tissue that has been moved, external pressure on the tissue will cause the blood supply to diminish. On the first days following surgery an individual assessment must be made of how much activity the patient can engage in and how much pressure can be applied to the flap. Optimalisation of the patient's nutrition is also important to ensure the best possible healing process (17).
The most common complications after reconstruction of the perineum are local wound infections and poor circulation in parts of the flap. Approximately one-quarter of the patients sustain a minor complication, which as a rule is addressed during the hospitalisation period. A total flap loss rarely occurs (18). A hernia after harvesting of the rectus muscle is not totally uncommon and can happen after discharge. The patients will often have reduced sensitivity in the reconstructed area as a result of nerves having been severed during the intervention. If the flap is too voluminous, the size of the flap could be reduced after the wound has healed.
In the five-year period 2016–20, the Section for Oncologic Plastic Surgery at Radiumhospitalet conducted 266 perineal reconstructions, whereof 168 (63 %) were reconstructions with a VRAM flap. Most of these reconstructions were undertaken after an abdominoperineal resection, where the anus and rectum were removed. As a rule, the patients underwent open surgery with an abdominal midline incision, enabling the VRAM flap to be harvested through an extension of the incision that was used for the oncological part of the surgery. As the proportion of abdominoperineal resections undertaken with minimally invasive techniques grows (19), reconstructive methods will be called for that enable a satisfactory reconstruction without the need for a midline incision in the patient (20).