The Queen Victoria Hospital, East Grinstead

Transcription

1 IRRADIATION INJURIES OF THE PERINEUM By R. L. B. BEARE, F.R.C.S. The Queen Victoria Hospital, East Grinstead MISGUIDED radiotherapy has in the past caused much misery, and continues to do so, although severe radiotherapeutic injuries are happily becoming less common. Irradiation burns of any part of the body are disfiguring, dangerous, and difficult to treat, but there are few regions of the body where a small dose or two of X-ray treatment can so readily cause so much havoc as in the perineum. These injuries are not very common and, as the writer has been responsible for the care of three such cases, it seemed useful to study others which have been treated at East Grinstead. Numerically, as so often happens, the series is disappointing, and in the last seven years only six such cases have been treated at this Unit. However, in spite of the small total, there do appear to be some points which are worthy of comment and which may be of assistance to others faced with a similar problem. The Cause of the Burn.--In five cases the X-ray treatment had been given for a benign lesion--pruritus ani in four (two of whom were doctors) and leukoplakia of the anal margin in one. The remaining case was a woman who had received a massive two-field irradiation for carcinoma of the cervix. The Dose of X-ray Treatment.--This was unknown in all cases. The two doctors said that they had received "multiple small doses " over a long period--eleven years in one case and twenty years in the other. The lesion in these two individuals was similar, each having a squamous-cell carcinoma of the anal margin, set in a circle of chronic irradiation dermatitis some 4 to 6 in. in diameter. The other four patients had received their burns as the result of overdose in two or three treatments only, and presented necrotic peri-anal ulcers which had failed to respond to " expectant treatment." Section of the excised tissue showed irradiation necrosis without malignant changes. Here, then, from the pathological standpoint is the expected result: that it is the chronic, multiple, small-dose burn which develops cancer. Treatment.--Clearly the only treatment is surgical excision of the burned area. This treatment is dictated by the symptoms and by the pathology of irradiation injury in this region. Constant weeping of the affected area, discomfort, and pain are the subjective :features of the chronic condition. From the pathological standpoint the eventual appearance of a squamous-cell carcinoma seems highly probable, and this in a.situation where the prognosis of such a tumour, even with radical excision and colostomy, is bad. The acute irradiation injury in the perineum does not carry the immediate xisk of malignant change, but no treatment short of excision and surgical repaicr, 22

2 IRRADIATION INJURIES OF THE PERINEUM 2 3 which should be undertaken only when the extent of the injury is defined, can heal the burn and avoid its sequela:. For closure of the peri-anal defect caused by excision, the choice lies between repair by means of a free graft, by mobilisation of large local flaps, or by a combination of both methods. The important point in selecting the method to be employed is whether or not the entire peri-anal skin has been excised--if the anal margin has been circumcised (Fig. I), leaving an annular defect, then repair by free graft should be carried out for the following reasons :-- I. The transposition flaps required to close this annular defect must, for geometrical reasons, be large, and a free graft is likely to be needed anyway for closure of the secondary defect. A free graft provides satisfactory peri-anal cover, whereas it is less satisfactory in the seat area. 2. Large buttock flaps are particularly prone to loss. 3. It is difficult or impossible to bring together two buttock flaps of safe design without tension in the midline, both in front and behind the anus, whether the flaps are based anteriorly or posteriorly. On the other hand a unilateral defect, or a defect across which a substantial bridge of peri-anal skin has been preserved, may be FIG. I Large annular defect unsuitable for flap repair alone. In lithotomy position defect is maximal and buttock skin is also maximally stretched. satisfactorily closed by local flaps, particularly when closure is possible by simple undermining and advancement rather than by rotation. The scrotum can be a most useful source of tissue in repair of perineal defects and, if the perineal skin anterior to the anus has been irradiated and must be excised, then this part of the defect may be made good by advancement of the posterior margin of the scrotum towards the anterior margin of the anus. This procedure will allow a more conservative design of any buttock flaps which may be used. Flaps from the buttock should be ultra-conservative in design and should not include any tissue showing even a trace of irradiation injury. The main blood supply to the skin of the buttock is by cutaneous branches of the inferior gluteal artery and by branches of the inferior rectal artery, which turn upwards around the lower border of gluteus maximus away from the anus (Fig. 2). Excision of the irradiated area implies division of the latter source of blood supply, while mobilisation of a buttock flap will divide the former (Figs. 3 and a). Hence the need for a conservative design. A further point to remember is that the lithotomy position, in which such operations must be carried out, puts the buttock skin on its maximum stretch. This has two results: firstly, the edges of an apparently moderate circumanal excision will retract to give a formidable defect after excision. Secondly, there is no elasticity whatever in the buttock skin in this position, so that closure by an apparently well-designed flap may be possible only at the expense of undue tension, or of lengthening the flap to an imprudent degree. Extension of the hip joints, when the operation is complete, will do much to reduce tension, but it will do nothing to increase the blood supply in a flap which is too long. Temporary colostomy is unnecessary as a preliminary in most of these cases.'

3 2 4 BRITISH JOURNAL OF PLASTIC SURGERY The bowels can be confined with the help of opiates for seven to ten days, by which time both flap and free graft are able to stand transient faecal contamination. On the other hand these patients, when first seen, often have a colostomy which has been carried out in an attempt to heal the irradiation injury. In such cases the perineal repair should be completed before the colostomy is closed. If CUTANEOUS 8RANCHES OF INF. RECTAL ARTERY TURNINO UPWARD AROUND LOWER BORDER OF OLUTEU$ HAXIHU$ FIG. z Blood supply of buttock skin from inferior gluteal and inferior rectal (hmmorrhoidal) arteries. FIG. 3 FIG. 4 Fig. 3.--Posteriorly based flaps. Excision has divided buttock blood supply from inferior rectal (hmmorrhoidal) artery. These flaps are already too long for their width and approximation at X will be impossible without further lengthening or backcut at B. Fig. 4.--Closure possible, but anteriorly based flap has poor blood supply. may be useful. Scrotum an anal stricture is present or if an extensive anal or anorectal dissection is contemplated, then a temporary, defunctioning, left iliac colostomy should be carried out. In this small series one case was repaired by means of free dermatome grafts only, one by a combined free graft and simple sliding flaps, and a further one, a small defect, by means of undermining and approximation alone. The remaining three cases were all repaired with buttock rotation flaps and all suffered significant loss of these flaps, two patients to a disastrous degree (Figs. 5 to IO). Late Results.--Two late complications may arise. The most predictable is a marginal stricture. This will appear inevitably if an annular peri-anal defect has been repaired, whether by flap or free graft. It is satisfactorily treated by one or two Z-plasties to the annular scar with transposition of triangular flaps of skin and anal mucosa. Prevention of the stricture by interdigitation of these tissues at the primary repair is unsatisfactory owing to the likelihood of loss of

4 IRRADIATION C a s e 2. INJURIES OF THE PERINEUM 2~; FIG. 5 Typical chronic irradiation injury. Experience has shown that this large annular area is unsuitable for flap repair. FIG. 6 Case 2. FIG. 7 Fig. 6.--Anus at right centre of picture. Area left of picture excised and ready for free graft. Area right of picture grafted two weeks before. Fig. 7.--Free dermatome graft applied. T h e basting stitches are a useful means of assisting application. FIG. 8 Case 4. FIG. 9 Fig. 8.--Injured area marked for excision. Flaps are both inadequate for closure yet too long for survival. Tile anatomical blood supply to these flaps has been divided (see Fig. 2). Distal_ third of each flap was lost. Fig. 9. ~ A n n u l a r defect established. Note retraction of margins in the lithotomy position.

5 26 BRITISH JOURNAL OF PLASTIC SURGERY the graft, the only result being damage and scarring of the anal canal. If, however, even a narrow bridge of anal margin has been preserved then strictures do not occur. The other possible complication is a shortage of skin in the FIG. IO Case 4. Flaps approximated. Note with this design the difficulty of closure at the anterior (upper) end of defect. The writer would now use free grafts for repair of this defect. transverse direction, and this may be manifest as a band or as an unstable scar in the coccygeal region. Two of these patients developed strictures post-operatively, and these were the two in whom an annular peri-anal defect had been created. In the remainder a bridge of anal margin was left intact and none developed a stricture. CONCLUSIONS I. Irradiation is a dangerous and unsatisfactory treatment for pruritus ani. This is recognised by rectal surgeons, and at St Mark's Hospital for Diseases of the Rectum the itching perineum is debarred from radiotherapy. On the other hand, several standard works on dermatology enthusiastically recommend X-ray treatment for this condition. In fairness to those who advocate treatment of pruritus ani by this means, it must be stated that a small dose of superficial X-rays will successfully relieve the irritation. The effect, however, is for a limited period only and, as the symptoms return, the patient presents himself for a further treatment. Eventually, after successive applications, the maximum dose is reached and the patient is denied further irradiation. It is at this stage that he may take himself to another hospital, where he denies any previous irradiation, knowing that, if he admits to it, further treatment (and relief of his itching) will be refused. Because of this danger of addiction, it is safer to withhold this treatment entirely, particularly in younger patients. 2. Irradiation burns of the perineum and peri-anal region should be completely excised and repaired, in order to alleviate distress and avoid probable malignant change. 3- Large defects or annular defects should be repaired by free grafting. 4- Buttock flaps, when used, should be ultra-conservative in design. 5. An annular peri-anal excision produces a predictable stricture which, should be corrected at a secondary operation.