PRIMARY NERVE REPAIR

INDICATIONS Any nerve which has been completely transected. If the wound is clean, attempt repair immediately.

If it is grossly contaminated, control infection first.

EQUIPMENT Use your finest monofilament sutures, needles, and needle holder. Use 8/0 sutures on 3 mm atraumatic needles. Any suture larger than 610 is too big. Use ophthalmic forceps and needle holders, and operating spectacles such as the Bishop Harman loupe.

Don’t use silk, catgut, human hair, or dexon because these are irritant. Coarse sutures may cause so much fibrosis that the nerve will never function again.

METHOD Explore the patient’s wound as described in Section 54.1. Find the cut ends of the nerve. Put his limb in the position which will help to bring them together.

Trim back both the cut ends of the nervec with a new sterile razor blade as in A, Fig. 55-8. Usually about 2 mm is enough.

Match the cut ends in their correct anatomical positions, without rotation. There are usually very fine blood vessels on one side of a nerve which will enable you to distinguish its two sides. Study the cross section of its fasciculi carefully, and get the two cut ends to match.

Try to put all sutures into the outer sheath of the nerve. Sutures deep inside it will interfere with its function seriously. For clarity, the sutures in Fig. 55-8 are shown much larger than they really are.

Pass two stay sutures through the outer sheath of the nerve on either side. Tie them and leave the ends long (B). Carefully hold the two ends of the nerve together, and ask an assistant to hold the ends in artery forceps. Put one or two sutures into the front of the nerve (C).

Pass one of your stay sutures behind the anastomosis (D), and cross the other one in front of it, so that you rotate the nerve as you pull them and expose its back (E).

Put one or two sutures into the back of the nerve. It may be easier to repair the back of the nerve first.

CAUTION! (1) Try not to put more than 8 sutures into the nerve, or there will be unnecessary fibrosis. (2) Don’t let any nerve fibres stick out of the suture line.

Manage the wound as in Section 54.1. If you are leaving the wound open for delayed closure, try to cover the sutured nerve with muscle or skin, and don’t leave it naked in the wound.

If necessary, make relieving incisions, so that you can move skin over to cover the nerve, or cover it with a transposition flap, as in Fig. 55-9. Or, least satisfactorily, cover it with a split skin graft.

Splint the patient’s limb in the position which best relieves tension on the nerve. If it is under tension, release the position of the splint slowly over several weeks. If you fail to do this, the sutures may pull out.

When you have removed the stiches from the patient’s wound, and are waiting for his nerve to recover, splint his limb to prevent contractures, and tell him how to prevent trophic ulcers forming. If he intends to pick up something which might be hot, ask him to feel its temperature with his normal hand.

HAVE YOU SUCCEEDED? TINELS SIGN Tap the course of the nerve, if the patient feels pins and needles over its distribuion, it is regenerating.

Examine and record the power of all the muscles that his injured nerve supplies. The most proximally innervated ones will recover first.

Figure 55.8: ANASTOMOSING A NERVE. A, the ends are trimmed with a razor blade. B, the stay sutures. C, an anterior suture. D, the stay sutures reversed. E, inserting a suture in the back of the nerve. F, the completed anastomosis, G, sutures pass through the epineurium only. Kindly contributed by Peter Bewes.