Role of Peripheral Nerve Surgery in the Treatment of Chronic Pain Associated with Amputation Stumps

Debilitating pain following amputation surgery affects the long-term success of the surgery and the patient quality of life. Such patients are grouped in the chronic pain category and are treated with high doses of narcotic pain medications and anti-depressants. Other treatments result in limited or temporary pain relief. Little attention has been given to the role of peripheral nerve surgery as an early treatment option for this group of patients.

A retrospective review of 13 consecutive patients suffering from chronic pain resulting from previous amputations was performed. Nine patients had below-knee amputations, 3 had foot amputations, and 1 had an above-elbow amputation. 12/13 patients had difficulty ambulating due to pain exacerbated by use of a prosthesis. All reported pain which interfered with their activities of daily living. Using a subjective preoperative pain scale of 0-10 (10 being severe), a mean pain scale of 8/10 was reported.

Eleven patients were referred to the senior author after other treatment options were exhausted. The suspicion of peripheral neuromas was raised by a positive Tinel sign in the respective nerve distributions and by pain alleviation after proximal nerve blocks. Two patients were treated by an intraoperative consult. The surgical treatment included excision of the neuromas and local implantation of the proximal nerve ends into muscle. By an average postoperative time of 2.5 months, the mean subjective pain score using the same scale was less than 1/10 (0.69). One below-knee amputee reported 5/10 pain but also suffered from radiation-induced dermatitis as a result of treatment for exostosis at the distal stump. The rest of the patients resumed painless ambulation with a prosthesis and reported drastic improvement in their quality of life.

Neuromas are often overlooked as the primary cause of pain suffered by patients who have undergone a surgical amputation. Other treatment modalities and medications are used with limited success and the pain evolves into that of a chronic nature. The authors institute a conservative treatment algorithm which includes physical therapy, desensitization, and pain control. If pain persists after 6 months, peripheral nerve surgery is utilized as an early treatment option. Modalities like spinal blocks and nerve stimulators are of limited value, as they treat only the symptoms and not the source of the pain. The surgical treatment of neuromas addresses the source of the pain and should be the treatment of choice for amputees who fail to improve with conservative management.