Carpal tunnel syndrome is well recognized as the most common peripheral neuropathy. Carpal tunnel syndrome has been associated with a number of medical conditions including tophaceous gout. By increasing the volume of the carpal canal contents, tophaceous gout can compress the median nerve.1
MATERIALS AND METHODS
Fifteen cases of gout in the carpal tunnel were identified from 2649 carpal tunnel releases performed over the past 15 years. All cases of gout in the carpal tunnel had pathology specimens confirming the diagnosis. An open technique was used in all cases described; no endoscopic releases were performed. Gouty tophi were identified by the chalky white deposits found in the flexor tendons or in the floor and were confirmed by electron microscopy (Figure). Monosodium urate crystals deposited in gout appear as strongly negatively birefringent (light parallel to yellow axis) thin tapered rods.
Under Bier block anesthesia, a longitudinal incision is made beginning ulnar to the pal maris longus tendon and extending from the distal wrist crease to the superficial palmar arch paralleling the third web space. The palmaris brevis, the superficial palmar fascia, and the superficial fascia of the forearm are divided. The superficial palmar arch is identified and blunt tip scissors are introduced under the transverse carpal ligament into the canal. Staying ulnar to the scissors, the transverse carpal ligament is divided. The proximal portion of the ligament is divided using a meniscotome. The median nerve and its motor branch are identified. The degree of compression of the nerve is noted and adherent tissue about the nerve is released. Tophi may be seen within the canal or within the flexor tendons. The tophi are debrided and synovectomies, if needed, are performed. In cases where the flexor tendons were involved with tophi such that debridement would be resection, no debridement was performed. The skin is closed with 4-0 nylon and a soft dressing applied.
Gouty tophi in the carpal tunnel were identified in 15 hands (13 patients). Twelve of 13 patients were men and average patient age was 68. Three patients had no history of gout at surgery. Eight of 10 patients with a history of gout developed carpal tunnel syndrome despite medical therapy. All patients improved following surgery. No recurrences of carpal tunnel syndrome were reported during mean 30month follow-up. Tophaceous gout was identified in the canal and confirmed histologically in 15 hands, revealing a 0.6% incidence.
Figure: "Hour glass" compression of median nerve (black arrow) with gouty tophi deposition (white arrow) along flexor tendon sheaths.
Tophaceous gout as an associated and causative factor in the development of carpal tunnel syndrome has been reported. Phalen1 reported 2 cases of gout in 439 patients treated for carpal tunnel syndrome. Cseuz et al2 reported 7 patients with gout in a series of 3 13. In botii series. gout was not documented in the carpal tunnel. Several case reports found tophaceous gout in the carpal tunnel, causing carpal tunnel syndrome.3"10 A large series has not been published to quantify the incidence of gout in carpal tunnel syndrome. Our study revealed a 0.6% incidence of tophaceous gout as a cause of carpal tunnel syndrome.
Gout should be considered in the differential diagnosis for carpal tunnel syndrome, especially in males. Three of our patients developed carpal tunnel syndrome due to tophaceous gout without prior clinical history or evidence of gout. Eight of 10 patients with a history of gout developed carpal tunnel syndrome despite adequate medical therapy. Given this evidence, consideration should be given for tophi as a cause of carpal tunnel syndrome, especially in older men despite medical treatment for gout.
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