Pain after Radial Sensory Nerve Grafting A. LEE DELLON and SUSAN E. MACKINNON From Baltimore, Maryland and Toronto, Canada. Four cases are described in which a nerve graft to the radial sensory nerve was successful in restoring sensibility to the dorsum of the hand but failed in controlling pain. All of these patients subsequently were successfully treated with excision of the nerve graft and proximal implantation of the radial sensory nerve into the brachioradialis muscle. The ideal operation for the management of the painful neuroma would be one designed to control pain and restore normal function to the injured nerve. A nerve graf: procedure has the potential to accomplish these goals and, in general, we are pleased with the results of nerve grafting in the management of neuromas involving nerves which subserve critical function (Mackinnon, Dellon, 1986a). However, we have been discouraged by our results in pain relief following radial sensory nerve grafting as have others (Noordenbos, 1981; Withrington, 1984). This report presents our experience in four patients with radial sensory nerve grafts. In each instance, the grafts have been successful in restoring sensibility but have failed in the long term to relieve pain. Material and Methods Four patients with grafts to the superficial branch of the radial sensory nerve have been evaluated between 1981 and 1985. Their historical data is presented in Table 1. Each was studied by measurement of moving two-point discrimination, (m2PD) pinch and grip strength, the presence of pain with wrist range of motion and response to direct palpation over the nerve graft. In all instances, the nerve grafts were successful in restoring sensibility but did not give the patient pain relief. All four of the patients were subsequently treated with re- exploration, excision of the nerve graft and transposition of the superficial branch of the radial into the brachioradialis muscle. At the time of re- exploration, the graft, and the proximal and distal radial sensory nerves were evaluated, excised and submitted for histological and morphometric analysis. Case Reports Patient 1. A thirty-six-year-old, right-handed mechanic sustained a work-related injury to his left wrist in April, 1980. The superficial branch of the radial nerve was repaired primarily. Because of persistent pain at the repair site and absent distal sensation, a 2 cm., two strand interposition, interfascicular nerve graft using the lateral antebrachial cutaneous nerve as the donor graft was carried out in November of 1980. By four months post grafting, sensibility began to recover distally. The patient received six months of Received for publicauon November, 1985. S. E. hlackinnon, Sunnybrook MedicaJ Centre, 2075 Bay&w Avenue, Toronto, Ontarm, Canada. VOL. I-B No. 3 OCTOBER 1986 TABLE 1 Clinical data. Case 1 (SM.) 2 (F. J.) 3 (J.S.) 4 (R.P.) Age/Sex 36 M Injury (day/month) 4/80 Initial repair (day/month) 4/80 Nerve graft (day/month) 12/80 Graft resection (day/month) 12/84 25 M 12/81 12/81 3/82 lo/83 20 M 10/82 Not repaired 7/83 7/84 24 M l/l9 l/l9 3/82 6/84 Pain (O-5) 3 4 5 4 m2PD (mm) 15 12 15 15 sh LB Injured Hand 15/65 5/50 3.5/35 18/60 -- Grip Normal Hand 18/65 18/100 22/60 22/80 Work status (Yes/No) Y N N N (with brace) Pain 0 1 2 0 m2PD 0 0 0 0 Pinch 1 a/75 20/80 15/50 22/80 -- Grip 20/90 25/12 25/12 26/90 Work status (Yes/No) Y Y Job Y (No brace) Retraining desensitization. At twenty-five months post grafting, he had recovered 20 mm, m2PD, 15 pounds pinch, 65 pounds of grip strength. He had moderate to severe pain when the graft was touched and pain with wrist movement (Figure 1). The nerve graft was excised and he returned to his previous job three months thereafter with complete relief of pain at the wrist. Patient 2. A twenty-five-year-old, left-handed labourer sustained a work-related laceration to his left wrist in December, 1981 and had a primary repair of his radial sensory nerve. By four months post injury, he was unable to work due to severe pain at the injury site. In March of 1982, he had a 2 cm. two strand, interposition, interfascicular medial antebrachial cutaneous nerve graft to the superficial branch of the radial. Two months post graft, he had good pain relief and returned to work. However, by six months post nerve graft he was unable to use his left hand due to pain. Despite eight months of rehabilitation, he was still unable to use his left hand as a labourer. At nineteen months post grafting, he had 12 mm, m2PD, 15 pounds of pinch, 50 pounds of grip and severe pain with wrist flexion. The nerve graft was excised in October of 1983 and the proximal end of the superficial branch of the radial implanted into the brachioradialis muscle 341