|Amputation for War Wounds (ICRC, 30 p.)|
The indications to amputate are well established (2-5) but the decision in individual cases can be difficult (8). A second opinion is invaluable and the prosthetic facilities should also be considered.
A pneumatic tourniquet is recommended to minimise blood loss during removal of the field dressing and the operation; recognition of viable tissue is not made difficult. An important point concerning its use is that after the operation, it must be released and haemostasis achieved before the dressing is applied.
*USE A TOURNIQUET FOR SURGERY*
The level and technique of amputation. One text advises that a guillotine amputation is performed proximal to the injury and the stump left open for subsequent closure by secondary intention or skin graft (5). Whilst this amputation might be preferable for the untrained operator outside a surgical environment, it must be recognised that, first, it may miss dead muscle due to the compartmental nature of the injury; second, it is unsuitable for amputation through muscular parts, i.e. calf or thigh, because of subsequent swelling; third, it is likely to require revision; fourth, it results in an amputation that is higher than necessary. For these reasons, guillotine amputations are not performed in ICRC hospitals.
An alternative approach for the field surgeon is amputation as distal as possible, through viable tissue and by techniques resembling civilian amputations (2-4). This approach may ensure that the first operative objective is achieved but does not take delayed primary closure of the stump into account. However, compared with guillotine amputation, the resulting stumps are preferable as few need subsequent revision (2,3).
Appropriate advice is: perform amputation of dead, damaged and contaminated soft tissue and then plan the bone section as distal as possible but ensuring that the remaining, viable soft tissue can be closed over the bone after a delay. In practice, this approach involves: trimming of skin edges and fat; raising flaps, with fascia, either formally or as determined by the injury; examining the damaged muscle so exposed; making the muscle section proximal to it and then the bone section. The skin, and preferably muscle aswell, should approximate easily at the end of the primary operation and so further bone shortening is unnecessary at delayed closure.
*LEAVE ENOUGH SOFT TISSUE TO COVER BONE*
Most patients are young men with bulky muscles which swell considerably in the four or five days between amputation and closure (figure 5). Skin flaps that approximate at the primary operation may only do so under tension at delayed primary closure; should the wound break down the bone section is exposed (figure 6). The texts that advise delayed primary closure (2-4) fail to recognise this problem which, if not accounted for, necessitates further bone shortening. An intact muscle left exposed swells much less, is more pliable and readily holds sutures; therefore, myoplastic amputations utilising complete muscles are recommended (9).
*DO NOT UNDERESTIMATE MUSCLE SWELLING*
The section of vessels, nerves and bone are by standard techniques. Vessels should be transfixed with an absorbable suture and the nerves distracted before they are cut. The front of the tibial section should be bevelled and sharp edges of bone filed; bone wax is not used; the periosteum is cut at the level of bone section without proximal stripping. It is recommended that extruding intercompartmental fat is also excised just proximal to the level of muscle section. This ensures that exposed fat does not necrose and impede delayed closure. The practice of placing a few large tension sutures to hold a compress between the skin flaps to prevent skin retraction is dangerous: it causes strangulation of skin and muscle.
*NEVER ATTEMPT PRIMARY CLOSURE OF THE STUMP*
The primary amputation is rinsed with normal saline and dressed with a dry and non constrictive dressing with sufficient quantities of gauze and cotton wool to soak up the exudate of the first 48 hours (figure 7). Soaking the dressings in an antiseptic solution is strongly discouraged. A plaster of paris splint may be beneficial if the patient is to be transported. It is stressed that this dressing does not routinely need changing before the date set for delayed primary closure.
When pain and swelling of the proximal limb is accompanied by deterioration of his general condition, the patient should be taken to theatre, given an anaesthetic for the dressing to be taken down and have the amputation revised with the same operative objctives in mind. The decision to undertake reamputation in a seriously sick patient with multiple injuries can be difficult. An offensive dressing alone is not a reason to suspect stump infection (10).
The use of skin traction needs clarification (3,4,11). It may help skin closure of the indurated and open stump where delayed primary closure has failed; further operation is avoided. The disadvatages are that the patient is confined to bed for a long period and that the resulting scar will be tethered to the bone; a subsequent stump revision is likely. When the primary surgery is performed correctly there is no need for skin traction; it will not help routine delayed primary closure.
Delayed primary closure.
All texts agree that the stump must be left open, permitting exudation of blood and serum and decompression of divided muscle. Primary closure should be performed between three and seven days later and only then if the stump is clean (2,3,4,9). The original operative dressing adheres to the fibrin coagulum that covers a clean wound; as it is peeled off, the divided muscles contract away in a characteristic manner. At this time skin and muscle are pliable. Fine absorbable sutures hold a myoplasty in place; skin flaps are closed independently by interrupted sutures incorporating deep fascia. Vacuum drainage of the stump is recommended for 48 hours after closure.
When the skin flaps are deficient, but the bone section is covered with muscle, a split skin graft can be applied (9). Should this subsequently interfere with prosthetic fitting, it can be excised after some months when the oedema has settled, the muscles wasted and the skin regained its normal elasticity.
An open stump which is not clean when the dressing is removed usually needs further excision of soft tissue and possibly bone. This is a difficult and bloody operation and contributes further to the patients anaemia. Alternatively, repeated antiseptic dressings may clean the wound but closure becomes more difficult with time as the soft tissue of the stump becomes indurated. These unsatisfactory measures affirm the importance of correct primary amputation.