Chapter 21 External and Internal Neurolysis

The Peripheral Nerve Operation

The general principles that underlie any surgical procedure apply to peripheral nerve operations. There are, however, some specific points that should be emphasized for patients undergoing peripheral exploration and repair.

The Day Before

The surgeon should review all pertinent information and, particularly, the duration of time between the time of nerve injury and surgery. The first appropriate target muscle should be memorized (e.g., the brachioradialis in the case of a midhumeral radial nerve injury). If a previous operation has been performed, the operative note should be reviewed. This record should be read with a very critical eye. Inappropriate nomenclature could alert the surgeon to the fact that the previous surgeon may not have had mastery of the field. (e.g., a reference to the cords of the brachial plexus when the surgery was in the supraclavicular space, or a reference to operating on nerve fibers, which are invisible to the human eye). Disproportionally long descriptions of how a nerve was particularly guarded and protected suggest that the operative note may have been revised once that an injury to that nervel was proclaimed clinically in the postoperative period. The surgeon should have a clear idea as to the probable site of pathology (e.g., is this likely to be a C5 and C6 spinal nerve injury or is it more likely to be musculocutaneous nerve pathology?).

Presurgical Pause

A brief, formal meeting of the surgeon, anesthetist, and operating room nurse should be held before the start of every case. Confirmation is sought as to the patient’s identity and the side and site of the proposed surgery. The probable duration of operation is reported and whether blood is likely to be required. The anesthetist should understand that no tourniquets will be used and that after exposure, the surgeon will want to stimulate the nerve or nerves and look for an appropriate muscular response. In appropriate cases, nerve action potentials (NAPs) will be recorded. All hospital protocols (e.g., preoperative antibiotic infusion) are checked for completeness. The informed consent document is reviewed so that everyone is reminded of what the patient has (and has not) consented to.

Operating Room Set-Up

The positioning of the patient, instrument table, back tables, the surgeon and assistant, and, possibly, the operating microscope should be explicitly rehearsed. On occasion, procedures are prolonged, and—particularly if microsurgery is contemplated—the positions of both surgeon and assistant should be reasonably relaxed and comfortable. The operating nurse should be quite clear as to whether sural nerve grafts may be harvested or whether a limb will be moved significantly during surgery. If this foresight is not a rule, surgeons may find that they are operating in peculiar, crouched positions for several hours or that aseptic technique is broken by unexpected movement of limbs during surgery.

Instrumentation

The operating room nurse should be confident that all instruments have been appropriately handled prior to their sterilization before the operation. Delicate microsurgical instruments require very careful handling and expensive endoscopic tools may have specific and special sterilization requirements.

A general set of instruments for routine nerve exposures should contain as few instruments as possible, as long as the inventory is appropriate for the intended procedure. A wide variety of self-retaining retractors is required. Plastic loops of various caliber and color are a significant aid to nerve dissection.

A set of microsurgical instruments should be prepared separately, because these are not required in every case. Once again, there should be standardization of the instrument pack, although it is not unreasonable to allow the microsurgeon a favorite needle holder or specific forceps design.

All significant peripheral nerve operations require appropriate instrumentation to manage vascular damage. In the main set, instruments should be present for this purpose. A more sophisticated vascular pack should be available to the operating room should serious difficulties be encountered.

Changing Gears

All should understand that the operation will not proceed at a uniform pace. Routine exposures should be completed with dispatch. Outstanding surgeons appear to operate slowly but complete procedures without delay. The secret is that there are no wasted movements. The surgeon is an absolute master of the anatomy. Operations are conducted through fascial planes whose anatomy is clearly comprehended. Muscle is rarely cut. Much is achieved by sharp dissection with a knife, using confident and safe technique; thus the field is relatively bloodless. Trainees should acquire all skills in an appropriate skills laboratory, not the operating room. A trainee who operates in a cell-by-cell manner with excruciating slowness shows clear evidence of a lack of anatomical mastery, and the supervising surgeon should remove such an operator immediately. A trainee who fumbles with the knot of an 8-0 suture under the microscope demonstrates too short a time devoted to skill acquisition in the laboratory

Normal nerve should be exposed on either side of the pathology whenever possible. The surgeon then “changes gears.” Operating loupes are worn where appropriate to ensure that planes are utilized accurately. At the completion of this phase, normal proximal and distal nerve and the lesion itself are dissected out. The response to direct stimulation of the nerve proximal to the lesion is carefully noted, because this is an accurate indicator of the degree of severity of the nerve injury, provided an appropriate time has elapsed since the insult. Where appropriate, NAP recordings are made.

In a deliberate fashion, the gears are once again changed. Suction pressure is significantly reduced so as not to accidently aspirate nerve graft. Assistants are banned from blotting the wound with surgical sponges, to prevent them from carrying off delicate grafts in the process. A decision is made as to whether grafts will be required; if so, those grafts should be dissected out without any injury to the axons they contain.

A further gear change is signaled by the conclusion of the nerve surgery. It must be emphasized that fatigue should not encourage shoddy work or substandard shortcuts at this stage. The steps that conclude the operation should be taken with as much care and skill as the opening stages.

Particular attention should be paid to keeping the patient immobile until the surgeon signals the anesthetist that it is safe for movement to occur. The transfer of the patient from table to gurney and from gurney to bed must be supervised and conducted by experienced personnel who retain their concentration despite many hours of taxing and tiring surgery. (Nothing quite spoils the surgeon’s day after a difficult and taxing high sciatic nerve repair than to have the patient’s leg dropped during transfer to the gurney.)

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