Nerve Damage and Nerve Reconstruction
When a hand injury occurs, any associated damage to nerves and blood vessels must be ruled out. In accidents that cause hand or arm injuries, there is often pinching, tearing or hyperextension of the nerves giving rise to paralysis and impairment in touch sensation in the affected area. The diagnosis is often made more difficult if the injuries are complex because the nerve must be visually inspected as much as possible in order to confirm it as undamaged. Therefore, surgical exposure of it while under general anaesthetic is necessary. In cases where there is good reason to suspect nerve damage, despite the complexity, this surgery is fully justifiable as any untreated nerve damage threatens to cause muscle atrophy as well as trophic and sensibility disorders in the affected nerves.
Primary Nerve Suturing
The reconstruction of completely severed nerves can only be accomplished by a nerve suture. If the nerve-endings are cleanly cut and no nerve tissue has been lost, then the nerve can be immediately (primary) sutured using microsurgery techniques. Afterwards, regular results-testing is required in order to monitor the healing process, possibly also using electromyography apparatus.
Secondary Nerve Suturing
If, for example, there are also extensive bone and tendon defects, then a primary and tension-free suture of the affected nerve is sometimes not possible. In such cases, the nerve ends are then only initially marked so they can be found without difficulty in a later operation. After approximately 1-3 months, further treatment can be carried out (secondary nerve suturing with or without transplantation). However, direct or immediate nerve transplantation is often successful today.
Should the nerve tissue be damaged to the extent that a tension-free suturing of the nerve ends is not possible, then a nerve can be transplanted from another part of the patient’s body. This nerve is usually taken from the calf, where the nerve of choice is the sural nerve because it has no motoric function and only supplies a small area on the outside of the foot.
Nerve damage is often not initially recognised. If the diagnosis is made within 1-2 weeks and the injury has been surgically treated, a primary suture can sometimes be made. If, however, scars have developed on the nerve stumps, these must be removed but due to the resulting reduction in nerve length, a nerve graft has to be introduced.
Generally, after isolated nerve suturing, the hand is required to be immobilized in a splint/cast for approximately 2 weeks. Otherwise, the aftercare and recovery process follows the pattern for a tendon injury. Should there be no hint of functional ability in the nerve after 4-6 months (depending on localisation of injury and patient’s), the nerve can possibly be operated on again.