1 62, M Biopsy Paget s disease 8/5/92 Perianal skin, None, NED anal canal,

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1 British Journal of Plastic Surgery (1999), 52, The British Association of Plastic Surgeons Reconstruction of perianal skin defect using a V Y advancement of bilateral gluteus maximus musculocutaneous flaps: reconstruction considering anal cleft and anal function K. Sasaki, M. Nozaki, Y. Kikutchi, T. Yamaki and K. Soejima Department of Plastic and Reconstructive Surgery, Tokyo Women s Medical College, Tokyo, Japan SUMMARY. In order to preserve the anal function after ano-perianal skin excision for malignancy, we have reconstructed a deep, symmetrical natal cleft using a V Y advancement of bilateral gluteus maximus musculocutaneous flaps thinned medially and sutured to the coccyx, anococcygeal ligament and the central tendon of the perineum. This technique was applied in three cases of Bowen s disease and two cases of Paget s disease. In all five cases, postoperative anal functions such as comfortable defecation and sensation, were well preserved, the perianal skin and underwear stayed clean, and there was no disturbance of walking or exercise. Keywords: perianal reconstruction, V Y advancement, gluteus maximus musculocutaneous flap, natal cleft. The perianal skin is a common site for extramammary Paget s disease, Bowen s disease and squamous cell cancer. 1,2 In the absence of an invasive cancer to the rectum, wide local excision is recommended. 2 4 A small skin defect may be closed directly, whereas a large defect after a wide local excision requires a splitthickness skin graft (STSG) 1,3 or a local skin flap. 5 There are difficulties with STSG, including infection, long-term confinement in the prone position to immobilise the skin graft, and anal stenosis caused by graft contracture. With flap reconstruction, problems include suture line contracture, disturbance of walking due to loss of the natal cleft, and skin faecal soiling due to hypoaesthesia of the flap. Although there have been reports describing anal sphincter muscle reconstruction in the ano-perianal area, 6 there have been few reports of reconstruction taking these problems into consideration. We have overcome these problems by reconstructing a deep symmetrical natal cleft using a V Y advancement of bilateral gluteus maximus musculocutaneous flaps with some technical refinements. Patients and methods During the last 6 years we have performed perianal defect reconstruction using this technique on a total of five patients, consisting of three cases of Bowen s disease and two cases of Paget s disease. These patients comprised three males and two females and ranged in age from 56 to 72 years, with a mean age of 61.4 years at the time of diagnosis (Table 1). None had a history of prior malignancy. Prior to surgery Cases 1 and 3 had undergone chemotherapy. Table 1 Patient summary Case Age, Method of Disease Date of Excised tissues Size of defect Complications, Follow-up no. sex diagnosis operation (length width cm) anal function status 1 62, M Biopsy Paget s disease 8/5/92 Perianal skin, None, NED anal canal, rectal mucosa 2 63, M Biopsy Bowen s disease 18/1/92 Perianal skin None, NED 3 59, M Biopsy Paget s disease 9/3/93 Perianal skin, None, Died of lung anal canal, FSS metastasis rectal mucosa 4 56, F Biopsy Bowen s disease 18/7/94 Perianal skin, 7 8 None, NED vaginal mucosa of posterior wall 5 67, F Biopsy Bowen s disease 11/12/95 Perianal skin None, NED FSS = Faecal soiling of the underwear on a soft stool; NED = No evidence of disease. 471

2 472 British Journal of Plastic Surgery Figure 1 Diagrammatic representation of a V Y advancement of bilateral gluteus maximus musculocutaneous flaps. This flap includes the lower third of the gluteus maximus muscle. necessary. This flap includes the lower third of the gluteus maximus muscle (Fig. 1). Since the sensory nerves enter the flap from the inferior margin of the gluteus maximus muscle and from the perineum, dissection of these areas should be carried out with care so as not to injure these nerves. In order to reconstruct a deep, symmetrical natal cleft, the medial portion of the flap is thinned by fat excision and fixed firmly to the tip of the coccyx, the anococcygeal ligament and the central tendon of the perineum. The anus or rectum is sutured to the neoanal verge of the flap, which is enlarged by a Y to M shape skin incision to prevent anal stenosis (Fig. 2). The patient receives an opium alkaloid to suspend bowel movement temporarily and rests on an air bed as postoperative care for 5 days. Case reports Figure 2 Reconstruction of a deep, symmetrical natal cleft. Fat tissue of the medial portion of the flap is excised so as to be thin (above; dotted line), and the flap is fixed firmly to the tip of the coccyx, anococcygeal ligament and central tendon of the perineum (below; arrow). Operative procedure The patient is placed in a prone, jack-knife position with maximum flexion. Following wide local excision, two V Y advancement flaps with a 1:2 2.5 width length ratio are marked on the gluteus maximus muscle on both sides of the skin defect. The width of the base of the flap should be the same as the width of the defect. A Doppler flow audioscope should be employed to confirm the course of the inferior gluteal artery which will be included in the flap. The skin incision around the flap is extended to the gluteal fascia, and the gluteus maximus muscle is separated along the muscle fibres at the superior limb of the flap. Muscle division is performed superficially at the sacrum and coccyx and laterally at the femur. Fullthickness division of the muscle is not always Case 1 A 62-year-old male had noticed eczematous dermatitis of the perianal skin about 18 months prior to referral to our clinic and had been treated by a dermatologist. Because the lesion persisted, a biopsy was carried out and Paget s disease was diagnosed. The perianal lesion measured 5 6 cm in size, and the anal verge was involved (Fig. 3A). The perianal skin was resected with a boundary of 2 3 cm around the lesion. Preserving the anal sphincter, the rectal mucosa was pulled out and excised 4 cm cephalad to the dentate line (Fig. 3B). Several frozen sections from the resected specimen were free of Paget s cells. The skin defect measured cm. The surgical defect and anus were reconstructed as described above (Fig. 3C and D). The patient remains tumour-free 5 years after the operation. His bowel and anal functions, including the sensation on defecation, are normal. There is no disturbance of walking or spreading-out of the lower extremities (Fig. 3E and F). Case 3 A 59-year-old male was diagnosed as having Paget s disease as a perianal lesion measuring 4 5 cm in size and involving

3 Perianal skin reconstruction using a V Y advancement of bilateral gluteus maximus musculocutaneous flaps 473 Figure 3 Case 1. (A) Paget s disease involving the anal verge. Markings of skin excision, Y to M shape skin incision for neo-anal verge, and V Y advancement flap. Shaded line shows the area of defatting. (B) Preserving the sphincter muscle ( ), rectal mucosa was pulled out and excised 4 cm cephalad from the dentate line shown by the arrow. (C) The skin defect is cm. The rectal stump should be held with silk sutures so as not to be lost in the wound. Fat of the medial portion of the flap is excised. (D) Y to M shape skin incision for the neo-anal verge to prevent anal stenosis. The rectal mucosa is sutured to the neo-anal verge. (E) 5 years after surgery. (F) The neoanus is kept large. the anal verge (Fig. 4A). The left inguinal lymph nodes were swollen. Biopsy revealed Paget s disease. There was no evidence of synchronous malignancy or distant metastasis. The perianal skin was resected with a free margin of 3 4 cm around the lesion (Fig. 4B). The resected margin of the rectal mucosa was 4.5 cm cephalad from the dentate line. Several frozen sections from the resected specimen were free of Paget s cells. The surgical defect and anus were reconstructed with flaps, as described above (Fig. 4C). Unfortunately, this patient died as a result of pulmonary metastases 18 months after surgery. Results The largest skin defect caused by reconstruction with this technique was cm. The largest portion of

4 474 British Journal of Plastic Surgery Figure 4 Case 3. (A) Paget s disease involving the anal verge. Markings of skin excisions, V Y advancement flap, and Y to M shape skin incision for the neo-anal verge. (B) Rectal mucosa was pulled out and excised 4.5 cm from the dentate line. The skin defect was cm. (C) Findings 4 months after the operation. The anus is located at the floor of a deep and symmetrical natal cleft. rectal mucosa excised was 4.5 cm in Case 3. The surgical wound healed without any troubles such as flap necrosis, infection or dehiscence, and there were no postoperative sequelae such as anal stenosis, faecal incontinence or rectal mucosal prolapse. The anal function was almost normal, except for faecal soiling of the underwear after a soft stool in Case 3. There were no cases of local recurrence. Discussion The natal cleft plays an important role in protecting the anus from trauma and assisting the lower extremities in their smooth motion. It also has the function of separating at the time of defecation, so that the anus is effectively exposed. For these reasons, when the functions of the natal cleft are ignored at the time of perianal skin reconstruction, there are likely to be problems such as disturbance of walking, pain and injury due to exposure of the anus and faecal soiling of the underwear. In addition, it must be kept in mind that the buttocks and natal cleft are also important as an erogenous zone of the human body, which means that the surgeon cannot ignore the aesthetic or sensory results of perianal skin reconstruction. For reconstruction of the perineum, musculocutaneous flaps using the gluteus maximus muscle, 5,7 gracilis muscle 8 or tensor fascia lata and gluteal thigh fasciocutaneous flaps 9,10 have been employed. However, these graft materials have been employed only with the objective of achieving coverage of the skin defect or filling a dead space, and there have been no reports of reconstruction which took into consideration the shape and function of the natal cleft. Anatomical reconstruction of the natal cleft is possible with any of the above flaps, but for reconstruction which also provides for sensation in the perianal region it is necessary to use a gluteus maximus musculocutaneous flap or a gluteal thigh fasciocutaneous flap. Many of the patients who require reconstruction of a perianal skin defect are elderly subjects in whom sensory switching is difficult. Thus, for such patients, we employ a V Y advancement of bilateral gluteus maximus musculocutaneous flaps. To provide sensation to the skin of these flaps, we employ mainly the perineal and inferior clunial branches of the posterior femoral cutaneous nerve and the pudendal nerve. In each of the five patients we reported in this paper, the sensation was when the reconstructed perianal region was cleaned after defecation. In addition, with the passage of time after the reconstruction, even Cases 1 and 3 in whom the anal canal had been excised, reacquired nearly normal sensation on defecation. Creation of a deep natal cleft reduces the tension on the suture line of the rectal mucosa and flap, thereby avoiding wound dehiscence. For these reasons, in the case of tumour invasion of the anal canal, it is possible to pull out and excise a greater length of rectal mucosa. In the cases we reported here, the excision of the rectal mucosa was performed to a maximum of 4.5 cm cephalad to the dentate line, yet wound dehiscence did not occur. These flaps have a rich blood supply, and for this reason it is not necessary to always keep the recovering patient in the prone position. This is also an important advantage of this reconstruction technique in comparison with a free skin graft or a free skin flap.

5 Perianal skin reconstruction using a V Y advancement of bilateral gluteus maximus musculocutaneous flaps 475 It must be noted that the reconstruction technique we describe here is not applicable to cases of invasive malignancy to the rectum or broad excision of perianal skin, which include excision of the inferior gluteal artery and vein. Acknowledgement We would like to thank Dr Sumiyoshi Koura, Chief of Department of Dermatology at Kagoshima City Hospital. References 1. Herzog U, Von Flue M, de Roche R, Curschellas E. Perianal extramammary Paget s disease: report of two cases. Eur J Surg Oncol 1993; 19: Strauss RJ, Levon LR, Tenenbaum N. Bowen s disease and Paget s disease. In: Fazio VW (ed), Current Therapy in Colon and Rectal Surgery. Toronto: Decker, 1990; Beck DE, Fazio VW. Perianal Paget s disease. Dis Colon Rectum 1987; 30: Beck DE, Fazio VW, Jagelman DG, Lavery IC. Perianal Bowen s disease. Dis Colon Rectum 1988; 31: Murakami K, Tanimura H, Ishimoto K, Yamaue H, Yamade N, Shimamoto T. Reconstruction with bilateral gluteus maximus myocutaneous rotation flap after wide local excision for perianal extramammary Paget s disease: report of two cases. Dis Colon Rectum 1996; 39: Shanahan DA, George B, Williams NS, Sinnatamby CS, Riches DJ. The long head of the biceps femoris: anatomic basis for its possible use in the construction of an electrically stimulated neoanal sphincter. Plast Reconstr Surg 1993; 92: Scheflan M, Nahai F, Bostwick J III. Gluteus maximus island musculocutaneous flap for closure of sacral and ischial ulcers. Plast Reconstr Surg 1981; 68: Giordano PA, Abbes M, Pequignot JP. Gracilis blood supply: anatomical and clinical re-evaluation. Br J Plast Surg 1990; 43: Hurwitz DJ, Swartz WM, Mathes SJ. The gluteal thigh flap: a reliable, sensate flap for the closure of buttock and perineal wounds. Plast Reconstr Surg 1981; 68: Stevenson TR, Grekin RC, Friedman RJ, Zucker SE. Squamous cell carcinoma of the perineum: management with Mohs surgical excision and gluteal thigh flap. Ann Plast Surg 1987; 18: The Authors Kenji Sasaki MD, Associate Professor, Motohiro Nozaki MD, Chief and Professor, Yuhji Kikutchi MD, Resident, Takashi Yamaki MD, Resident, Kazutaka Soejima MD, Resident, Department of Plastic and Reconstructive Surgery, Tokyo Women s Medical College, 8 1, Kawada-cho, Shinjuku-ku, Tokyo 162, Japan. Correspondence to Associate Professor Kenji Sasaki. Paper received 2 June Accepted 22 February 1999, after revision.