8 Functional Reconstruction of the Perineum and Pelvic Floor Alan D. McGregor 1. Introduction The pelvis and perineum house closely related anatomical structures belonging to the urinary, reproductive, and gastrointestinal systems. Dis- eases, whether inflammatory or neoplastic, can spread readily from one organ to another. As a consequence, removal of the structure in which a disease has arisen may, under certain circumstances, entail concomitant removal of part or all of other related organs. Thus, for example, it may be necessary to remove a portion of vaginal wall as part of the abdominoper- ineal resection of Crohn’s disease or rectal cancer. All the structures in this part of the human body are highly specialised and it is possible to dispense with some without the need for sophisticated reconstruction. An end colostomy or an ileal conduit will replace rectum and anus or bladder adequately. What the end result of each lacks in aes- thetics, it makes up in technical simplicity and ease of management for the patient. Of greater significance is the fact that each of these problems can be resolved by the same surgeon who carries out the resection of the dis- eased viscus. The experience and technical range of individual surgeons varies, but overall tends to be limited by the scope of the training syllabus and the boldness of the trainers. Even allowing for a degree of overlap between specialties, neither gynaecologist, urologist, nor colorectal surgeon has the training or experience to reconstruct every defect he is likely to create in resecting the more complex diseases with which he is confronted. Whatever his (or her) specialty, the surgeon working in this field who is involved in treating extensive diseases will inevitably have to co- operate in the planning of surgery with colleagues in related surgical disciplines. The need to reconstruct presupposes the existence of a defect. Some defects can be repaired readily by the surgeon who created it. A good example is the pelvic floor after an abdominoperineal resection for bowel cancer. Other defects demand the expertise of a reconstructive surgeon 154 8. Functional Reconstruction of the Perineum and Pelvic Floor 155 trained in techniques of plastic surgery.While it is fair to say that most sur- geons have experience of some reconstructive techniques, that exposure is inevitably limited and is invariably restricted to a narrow range of tech- niques. These may be appropriate for a significant proportion of recon- structive problems, but not all. Every method has its limits and, with experience, every operator learns what these are. As a result, situations will arise when it is either necessary to push the technique of repair as far as or beyond the limits of its tolerance or to compromise the resection in order to permit reconstruction to take place. Whichever, the potential for disas- ter is considerable. The experienced surgeon can estimate with reasonable certainty which resections are likely to create a defect requiring sophisticated repair. Col- laboration with a reconstructive plastic surgeon has two distinct advantages for the colorectal surgeon. The first is the importation of knowledge and experience of all the possible reconstructive techniques that may be required. The second is that the resection can be carried out without concern for the defect that may result. This liberating effect means that the disease is treated properly with whatever margins of excision may be required. Put bluntly, the norm is FIRST MAKE THE HOLE,THEN FILL IT! This can be expanded to “the first team makes the hole and the second team fills it.” In this field of surgical practice, the macho individual who believes that he can do it all himself is a self-deluding dinosaur. The multidisciplinary team approach has everything to commend it. The ideal team contains a gynaecologist, a urologist, a colorectal surgeon, a clinical oncologist, and a reconstructive plastic surgeon. This blend works well in practice because, individual personalities apart, there is little overlap but each complements the others. 2. General Philosophy The elements of reconstruction can be subdivided conveniently into those that address the issue of function and those that restore appearance. On occasions there is a degree of overlap. Some aspects of function are depen- dent on the effects of the resection. For example, sexual function in the male after pelvic surgery is dependent in large measure on preservation of auto- nomic nerve supply—if this has to be sacrificed, it cannot be reconstructed. Similarly, it may not be necessary to reconstruct bladder or bowel because diversion via the anterior abdominal wall may be satisfactory.The uterus is often sacrificed and cannot be replaced. Reconstruction of pelvis and perineum is required only under certain cir- cumstances.These are (a) (extended) skin loss, (b) partial (rarely complete) vaginal removal, (c) perineal proctectomy, (d) pelvic floor loss, and (e) exci- sion after radiotherapy. 156 A.D. McGregor Each of these, singly or in combination, can be anticipated at the plan- ning stage before surgery. No surgeon can be absolutely confident under all circumstances about what the postexcisional defect will be. As a conse- quence, the reconstructive surgeon is rarely able to counsel any patient with confidence prior to surgery about what form reconstruction will take. Para- doxically, this uncertainty, born of experience, has a reassuring effect upon patients as a general rule. Patients in this position recognise that any surgeon who is prepared to make such a statement is one who has both knowledge of his subject and judgement. 3. Anatomy and Function The pure and applied anatomy of the pelvic floor and the perineum are, rel- atively speaking, minor considerations in the context of repairing the defect resulting from abdominoperineal excision of the rectum in cases of rectal carcinoma. The cutaneous perineal incision is made close to the anal margin, dissection of the bowel is in a plane close to the wall of the viscus and the pelvic diaphragm, pelvic floor and the cutaneous wound can be repaired directly with sutures. The intervening space may be drained. Although overall the management of the postexcisional defect barely merits the description of reconstruction, that is precisely what has been per- formed, albeit in its simplest form. The colorectal surgeon, in closing his postexcisional defect in the stan- dard manner, is recognising the implicit function and role of the pelvic diaphragm and the skin. It is, consequently, appropriate to consider the rel- evance and importance of each in relation to function and the need for reconstruction. This needs to be considered both in the context of why reconstruction is necessary, what form this may take, how the anatomy of each helps, hinders, or obviates the need for reconstruction, and the conse- quences of failure to undertake proper functional repair. Put simply, the principal role of the pelvic diaphragm is to support the abdominal and pelvic viscera and to prevent prolapse of these organs into the perineum. Some organs pass through the pelvic diaphragm—removal of any of these requires repair of the resultant defect to restore the integrity of the pelvic floor and prevent prolapse or the feeling of dragging or “some- thing coming down” of which patients with this problem complain. Because the muscles and fascia are draped in a bowl-shaped configuration, repair by direct suture is usually not a problem. Tension-free closure and a good blood supply invariably lead to problem-free healing with a good functional result. The skin of the perineum has a considerable degree of inherent laxity that allows a wide range of flexion/extension and abduction at the hip. In the midline the skin is more closely adherent to underlying structures. The skin lies immediately over the fat in the base of the ischiorectal fossa where 8. Functional Reconstruction of the Perineum and Pelvic Floor 157 it is extremely mobile. As a consequence skin will move medially without excessive tension being placed on it. Advantage of this mobility is routinely taken in obtaining tension-free closure after simple rectal incision. Even if skin suture appears to be under tension with the hips in a position of abduc- tion, the tightness is invariably relieved (or, at worst, reduced to an accept- able level) when the thighs are brought into a position of adduction at the end of the operation. On occasion, however, direct skin closure becomes impossible due to the need to extend the cutaneous excision margin further laterally. Such wider excision is invariably required due to the need to resect diseased tissue, on occasion aggravated by previous excisional surgery. As a general rule, a wide skin excision margin is an intrinsic element in an extended resection of the rectum and, more often than not, a wide resection of the pelvic floor. Thus, the above-mentioned anatomical and functional areas, although separate in theory, tend to form part of a single reconstructive problem— exceptions are procedures such as perineal proctectomy in which pelvic floor reconstruction is not a problem. The problem for the reconstructive surgeon (who invariably has no more than a concept of what the eventual problem confronting him is likely to be) is whether transfer of one or of more than one tissue is likely to be required. He is, however, fortunate that the usual surgical positioning of the patient in the modified Lloyd Davies position places at his disposal all the tissues he is likely to use without the need to prepare other parts of the body. In addition, it is possible to have two teams working simultane- ously on the abdomen and the perineum, which results in a considerable saving in total anaesthetic and operating time. 4. Tissues for Reconstruction When contemplating repair and reconstruction the surgeon must remem- ber what he is trying to achieve: (a) pelvic floor repair, (b) skin integrity, and (c) obliteration of the intervening surgical dead space.