Peripheral Nerve Injuries Treatment & Management

Updated: Dec 01, 2020
  • Author: Stefanos F Haddad, MD; Chief Editor: Murali Poduval, MBBS, MS, DNB  more...
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Approach Considerations

Indications for nerve injury surgery are as follows:

  • Closed nerve injury - If there is no evidence of recovery, either clinically or from electrodiagnostic studies, at 3 months after injury, surgery is recommended; if there is evidence of recovery as indicated by motor unit potentials (MUPs), patients should be assessed to determine the progression of recovery and the possible requirement for surgery
  • Open nerve injury (ie, laceration) - Surgical exploration is recommended as soon as possible; all lacerations with a reported loss of sensation or motor weakness should be surgically explored
  • Crush nerve injury - Surgical exploration of the nerve may be delayed for as long as several weeks; however, if, after 3 months, there is no evidence of reinnervation, either clinically or from electrodiagnostic studies (the absence of MUPs signals the absence of reinnervation), surgical reconstruction with nerve repair, transfer, or grafting is indicated

In contaminated or crush nerve injuries, delayed reconstruction may be indicated.


Nonoperative Therapy

In patients with motor nerve injury, initial therapy involves patient education and protection of the joints, including the surrounding ligaments and tendons, from further stress. Splints, slings, or both may be used in these cases to protect the joint and to augment function. For example, a radial nerve injury results in a loss of wrist and finger extension, a wrist drop. A wrist-resting splint may be used to support the hand in a neutral wrist position and place the hand in a more functional position.

In patients with brachial plexus nerve injuries, particularly when C5-6 is affected, continued downward stress at the glenohumeral joint may cause glenohumeral joint subluxation without the muscle support of the rotator cuff muscles. A sling is helpful to unload this joint, prevent complete shoulder dislocation, and decrease pain.

Physical therapy is started in the early stages after nerve injury to maintain passive range of motion in the affected joints and to maintain muscle strength in the unaffected muscles.

No definitive studies have been done to support the use of electrical muscle stimulation to prevent muscle degeneration. In cases of muscle denervation, galvanic direct current stimulation is necessary to elicit a muscle contraction. The risks of galvanic stimulation include a thermal burn beneath the electrodes, particularly in patients with decreased sensation. Because no studies have shown that electrical muscle stimulation using surface electrodes will stop total degeneration of the muscle fibers, the neuromuscular junction, or both, the authors do not advocate direct current stimulation of denervated muscles. If the nerve does not regenerate in time to reinnervate the muscle, there is no need to stimulate the muscle.

With reinnervated muscle, it is theoretically possible to use alternating current stimulation. However, it is necessary to have a large number of reinnervated muscle fibers to stimulate the muscle with alternating current. The authors recommend exercise and biofeedback strategies to increase the strength of a reinnervated muscle, in combination with sensorimotor reeducation.


Surgical Therapy

Treatment of specific injury types


In patients who have neurologic deficits after a laceration, an operative procedure to explore the nerve should be performed as soon after injury as possible. With clean, sharp injuries to the nerve, a direct repair is performed. Direct nerve repair with microsurgical techniques is a gold-standard method for treatment of axonotmesis and neurotmesis; it provides endurance and continuity between the distal and proximal parts of the nerves. [10] With more crushing or avulsion injuries, the nerve ends are reapproximated so that motor and sensory topography can be aligned. The definitive reconstruction is done at 3 weeks or when the wound permits. [11, 2]

Gunshot or blast wounds

Typically, blast wounds associated with neurologic deficit have good potential for neurologic recovery. Thus, unless an associated vascular or bony problem is present, patients with a neurologic deficit after a gunshot or blast injury are initially managed nonoperatively and monitored with frequent clinical examinations. If, by 3 months after the injury, no evidence of clinical recovery or electrical recovery is noted on electrodiagnostic testing, surgical exploration is recommended.

Closed injuries

In patients with closed traction injuries, surgical intervention is recommended 3-6 months after the nerve injury, depending on patient and injury factors. These patients are reexamined both clinically and with electrodiagnostic studies. If there is no evidence of reinnervation either clinically or on electrodiagnostic studies, surgical intervention is necessary.

Preparation for surgery

When there is no clinical or electrodiagnostic evidence of recovery, surgical exploration is recommended. Preoperative evaluation includes a comprehensive sensory and motor assessment. Initial sensory evaluation includes assessment of protective sensation (thermal), tactile (threshold monofilament) and discriminatory function (two-point discrimination) and pain. In patients with no two-point discrimination, light touch (Ten test) is used. [12, 13]  In the Ten test, simultaneous light touch stimuli are applied to the affected area of sensory compromise and to the contralateral region, and the patient compares the sensation on a scale of 0-10.

Motor assessment should include pinch and grip strength measurements and evaluation of individual muscle strength, which can be quantified by  using the Medical Research Council (MRC) 0-5 grading scale when appropriate. MRC grades are defined as follows:

  • M0 - No contraction
  • M1 - Flicker contraction
  • M2 - Muscle contraction with active motion with gravity eliminated
  • M3 - Full range of motion against gravity
  • M4 - Full range of motion against gravity with some resistance
  • M5 - Full range of motion against gravity with maximum resistance for that muscle

Operative details

Key technical points include the following:

  • Loupe magnification, preferably ×4.3, is employed with use of the microscope for microneurosurgical repairs or grafts
  • Extremity surgery is performed using tourniquet control
  • Nerve coaptations are performed with 9-0 microsuture and no tension at the repair site
  • Bupivacaine is used at the incision site, and in some cases, it also may be used in an infusion pump to control postoperative pain
  • A Jackson-Pratt drain also may be used in some cases to control postoperative drainage

Nerve repair

Reconstruction of nerve continuity can be performed with direct repair. [2]  This is performed when the distal and proximal ends of the nerve are directly coapted. The repair should be performed without tension; if it cannot be performed without tension, another type of nerve reconstruction should be performed (eg, nerve graft or nerve transfer). If the adjacent joint must be flexed or extended to permit coaptation of the distal and proximal ends of the nerve, another type of reconstruction (eg, nerve graft or nerve transfer) should be used.

Nerve graft

In cases where the proximal and distal nerve segments cannot be approximated without tension or where a gap is present between the proximal and distal end of the nerve, a nerve graft may be recommended. [11, 14, 15, 2, 16]  The use of a donor nerve to reconstruct the nerve gap results in a sensory loss in the distribution of the donor nerve. This area of sensory loss becomes smaller over 1-3 years with collateral sprouting from the surrounding sensory nerves. [17]

There are a number of small noncritical sensory nerves that may be used for nerve grafts. In cases where a large nerve gap is present, the sural nerve is used because of the large length of nerve graft material that can be obtained. The sural nerve can be harvested through a single long incision or through multiple step incisions on the posterior calf.

For shorter nerve gaps, the anterior branch of the medial antebrachial cutaneous (MABC) nerve is a good graft donor because the donor site scar is minimal and the resultant sensory loss is on the anterior aspect of the forearm. The MABC nerve is especially useful for upper-extremity surgical reconstructions because all of the incisions are located in the same extremity. The lateral antebrachial cutaneous (LABC) nerve provides about 6 cm of nerve graft material, but the scar on the forearm is more noticeable than that on the inner upper arm for the MABC.

Nerve transfer

The concept of a nerve-to-nerve transfer utilizes a normal neighboring noncritical nerve that is coapted to the distal end of the injured nerve. [18]  This is a particularly useful approach in cases where a large nerve gap is present, proximal nerve injuries are present, or both. [18, 19, 20, 21, 22, 23, 2]  Excellent results have been shown with proximal brachial plexus injuries and distal median, radial, and ulnar nerve injuries. [24, 25, 26, 27, 28, 29]


Postoperative Care

The patient is immobilized in a bulky dressing for several days postoperatively. The postoperative dressing (including the drain and pain pump, if used) is removed 2-3 days after the procedure.

The area of nerve coaptation then is immobilized for a longer time postoperatively (nerve graft, 10-14 days; nerve repair, 3 weeks; nerve transfer, 7-10 days), though the patient is instructed in range-of-motion (ROM) exercises for the joints proximal and distal to the immobilized region. For example, a median nerve repair at the wrist would be immobilized with a wrist-resting splint, and the patient would continue with ROM for the fingers, elbow, and shoulder.

After the surgical procedure, the patient is referred to the hand therapist, initially for immobilization (eg, splinting), education regarding postoperative care, and exercises. The initial goals of postoperative therapy are to regain passive ROM of the joints and soft tissues that have been immobilized. The patient should be instructed in exercises to maintain strength in the unaffected muscles. In the later stages, sensory and motor reeducation are recommended to maximize the outcome.



Complications of nerve surgery are similar to those of other types of surgery and include infection, hematoma, seroma, and injury to surrounding structures, including vascular structures or nerves, particularly in complex reconstructions involving mixed nerve injuries or scarred regions.


Long-Term Monitoring

Initially, the patient is monitored for postoperative wound healing. After immobilization and once full passive ROM has been regained, the patient is monitored every few months to evaluate for evidence of distal target reinnervation.

With nerve regeneration, a Tinel sign progresses distally along the nerve. With muscle reinnervation, a muscle contraction is visible; and with sensory reinnervation, the patient initially responds to light touch. Depending on the level of injury, the patient may continue to progress for varying periods; with distal injuries, maximal function is reached more quickly than with proximal brachial plexus injuries, which continue to improve 2-3 years after surgery.