O&P Library > POI > 1985, Vol 9, Num 3 > pp. 157 - 159

Case note: Foam elastomer dressing in the management of a below-knee amputation stump with delayed healing

C. P. U. Stewart *

Abstract

This case note concerns an elderly amputee who presented with delayed healing in the stump. The use of a Silastic foam dressing is described which allowed both prosthetic fitting and final healing to occur simultaneously. The patient's stump ultimately healed and the subject was successfully discharged home walking with his prosthesis.

Introduction

The local environment can be highly important in encouraging primary wound healing following ischaemic limb amputation.

The amputation stump is frequently contained within soft dressings, plaster of Paris or, in a few cases, a controlled environment (Troup, 1983). Despite considerable care, failure of primary healing is not uncommon. The need for further surgery occurs in up to 20% of cases (Dundee Limb Fitting Centre, unpublished figures). In 12% of these, local wedge resection allows knee joint preservation, but 8% may require further surgery to a higher level.

In situations where the suture line fails to heal locally it is customary to use fabric dressings to ensure the cleanliness of the wound, encouraging granulation to occur and final skin epitheliasation. The ideal dressing however should be non-adherent, non-allergic and slightly absorbent. This should reduce the outer layer fibroblast and capilliary damage in the granulating wound which occurs with the use of gauze packing. The use of foam elastomer dressings fulfills the above criteria and a case using this dressing is described.

Method

Patient:

A 77 year old male who had intermittent claudication for some time developed pregangrenous changes in his feet. Vascular surgery was not possible and assessment in the vascular laboratory by way of thermoscan and skin blood flow indicated that below-knee amputation was likely to be successful.

Skin blood flow was observed as;—12.4 ml/lOOg/min. medial; 12.6ml/100g/min. lateral; 16.9ml/100g/min. posterior.

The measurements were made using radioisotope washout technique, taken at 10cm and 3cm on either side of the anterior tibial tubercle and 15cm distal posterior to an imaginary line drawn from the anterior tibial tubercle posterior to the popliteal area.

A Burgess style long posterior flap amputation was performed, one Redivak drain and a plaster of Paris dressing was applied. The drain was removed at 48 hours. The suture line became infected with Staph. Aureus sensitive to Cloxicillin which was used and the stump responded to treatment. The stump almost completely healed by the 22nd day after surgery leaving a small hole (12mm) which showed no signs of improving (Fig. 1, top).

A foam elastomer dressing was used for ten days and then discontinued as the stump was almost completely healed. The patient was cast for his prosthesis with the foam in situ (Fig. 1, centre) on the 22nd day post-amputation and was using it with the foam in situ thereafter. Complete healing was achieved and prosthetic fitting successfully accomplished with a conventional PTB and the patient discharged home with a healed stump (Fig. 1, bottom).

Foam

The foam was Dow Corning Silastic foam dressing. This consists of a silicone base which must be thoroughly mixed prior to the addition of the supplied catalyst. Further vigorous mixing for 15 seconds with the stirrer supplied produces the prepared dressing.

The dressing is then poured or applied by way of a syringe into the wound. The foam expands to four times its original volume and is ready in three to four minutes.

The dressing (stent) is soft yet resilient and comfortable. If the dressing is too large it can be trimmed to size with scissors. Daily washing of the stent in chlorhexedine solution is advisable in order to maintain cleanliness and retain its soft pliancy. As healing occurs the stent becomes too large and a new one should then be fitted.

Discussion

The use of Silastic foam dressings has been described before by Wood and Hughes, 1975; Wood et al, 1977; Harding and Richardson, 1979; Harding et al, 1980; Regnard and Meehan, 1982 and Shukla, 1982. In all, the foam dressing was comfortable, reduced nursing workload and allowed healing to occur. Young and Wheeler (1982) compared dextranomer beads and silicone foam dressings in surgical wounds. No difference was found in healing rate using both dressings but the foam was considerably cheaper.

In a multi-centre prospective trial comparing conventional dressings and Silastic foam no difference in healing time was found (Williams et al, 1981). Wood et al (1977) however reported that hospitalization time was markedly reduced, the patient being able to return home far quicker with a foam dressing in situ. There was a general overall improvement in comfort when compared with conventional dressings. The foam is nontoxic (Yeakel, 1968) and non-carcinogenic (De Cholnoky, 1970). Use in stump wound healing has not apparently been reported. In the case demonstrated delayed healing did not interfere with prosthetic casting and fitting. The use of a silicone stent allowed both to occur simultaneously, the patient finding the stent very comfortable. Ultimate healing was achieved and the patient was discharged home successfully fitted with a PTB prosthesis.

Acknowledgements

I am grateful to Mr. S. Gairns for the photographic record and should like to thank Mrs. M. Copland for typing the manuscript.

References:

1. Harding, K. G., Richardson, G. (1979). Silastic foam elastomer for treating open granulating wounds. Nurs. Times, 75, 1679-1682.
2. Harding, K. G., Richardson, G., Hughes, L. E. (1980). Silastic foam dressing for skin graft donor sites-a preliminary report. Br. J. Plast. Surg. 33, 418-421.
3. Macfie, J., McMahan, M. J. (1980). The management of the open perineal wound using a foam elastomer dressing: a prospective clinical trial. Br. J. Surg. 67, 85-89.
4. Morgan, W. P., Harding, K. G., Richardson, G., Hughes, L. E. (1980). The use of silastic foam dressing in the treatment of advanced hidradenitis suppurativa. Br. J. Surg. 67, 277.
5. Regnard, C. F. B., Meehan, S. E. (1982). The use of silicone foam dressing in the management of malignant oral cutaneous fistula. Br. J. Clin. Pract. 36, 243-245.
6. Shukla, H. S. (1982). Cosmetic and functional advantages of foam elastomer dressing in the management of epidermoid cancer of the cheek. Br. J. Surg. 69, 435-436.
7. Troup, I. M. (1983). Care of the lower limb amputee (1). Update, 26, 1523-1532.
8. Williams, R. H., Wood, R. A., Mason, M. C, Edwards, M., GoodAll, P. (1981). Multicentre prospective trial of silastic foam dressing in management of open granulating wounds. Br. Med. J. 282, 21-22.
9. Wood, R. A., Hughes, L. E. (1975). Silicone foam sponge for pilonidal sinus: a new technique for dressing open granulating wounds. Br. Med. J. 4, 131-133.
10. Wood, R. A., Williams, R. H., Hughes, L. E. (1977). Foam elastomer dressing in the management of open granulating wounds: experience with 250 patients. Br. J. Surg. 64, 554-557.
11. Yeakel, M. H. (1968). Physical properties of silicone foam In: U. S. Army Medical Biomechanical Research Laboratory. Technical report no. 6802. Washington D.C.: Walter Reed Army Medical Centre.
12. Young, H. L., Wheeler, M. H. (1982). Report of a prospective trial of dextranomer beads (Debrisan) and silicone foam elastomer (Silastic) dressings in surgical wounds. Br. J. Surg. 69, 33-34.

O&P Library > POI > 1985, Vol 9, Num 3 > pp. 157 - 159