• Do not use this technique in recurrent carpal tunnel syndrome for a repeat procedure when an open procedure was done previously.
• Never exert force in passing instruments across the ligament without good visualization to avoid cutting the median nerve.
A positive Tinel's sign is present directly over the palmar cutaneous branch of the median nerve, which the patient says simulates her numbness and tingling to the thenar eminence. In addition to this, she has an area of numbness of 3 X 2 cm directly over the area of innervation at the palmar cutaneous branch of the median nerve in her palm. Her Phalen's test is positive and her Tinel's test to the wrist is negative. Her median nerve compression test is positive and her Weber static two-point discrimination is greater than 1 cm to all her median innervated digits. The patient's grip strength is 110 on the left and 110 on the right on the Jamar dynometer. Pinch is 18 pounds on the left and 18 pounds on the right. All measurements are an average of three trials.
Radiographs are negative for bony or soft tissue abnormalities. Electromyograms (EMGs) show nerve conduction velocities significantly slowing at the median nerve distribution more on the sensory fibers, even to the index with proximal conduction and ulnar conduction normal.
Carpal tunnel syndrome
Moderate Carpal Tunnel Syndrome with Compression of the Palmar Cutaneous Branch of the Median Nerve
Carpal tunnel syndrome is one of the most common conditions of the hand. Swelling of the median nerve or compression of the median nerve by surrounding structures causes sensory and motor disturbances (Fig. 12—1). Chronic repetitive stress on the carpal tunnel and the median nerve within it is the most common cause of idiopathic carpal tunnel syndrome. Occupations that require stress on the wrist, such as typing and carpentry, often lead to a high incidence of carpal tunnel syndrome. Sporting activities that involve repetitive or continuous flexion and extension of the wrist, such as cycling, throwing sports, racquet sports, archery, and gymnastics, also predispose individuals to carpal tunnel syndrome.
Carpal tunnel syndrome can be diagnosed by obtaining a careful patient history. Common complaints include nocturnal paresthesia, a heavy feeling, or hands going to sleep. Pain may radiate up the arm to the shoulder and neck. Patients also complain of weakness that hinders their ability to grasp objects. Numbness when gripping objects may prevent the patient from being able to lift objects.
Nonoperative treatments include activity modification, splinting (Fig. 12-2), magnetic support wraps, and injections (Fig. 12-3). In younger patients with early stages of carpal tunnel syndrome, these modalities may relieve symptoms. Following failed conservative treatment, patients may require surgical intervention to regain lost function. Open carpal tunnel release has been shown to relieve symptoms of median nerve compression for many years (Fig. 12-4). Endoscopic carpal tunnel re-
Figure 12—2. Custom carpal tunnel splint with wrist in
lease was shown to reduce tissue trauma and speed postoperative recovery. However, the endoscopic technique requires extensive equipment and has a steep learning curve. In our patients, we perform a limited open incision carpal tunnel release. This technique combines the advantages of the open procedure with the advantage of reduced tissue trauma and postoperative morbidity of endoscopic release.
The patient is brought into the operating room and a localized injection of anesthesia is injected at the wrist and into the carpal canal (Fig. 12-5). A 2- to 2.5-cm incision (Fig. 12-6) is made parallel to the radial side of the ring finger and one-third distal to and two-thirds proximal to a proximal line extending slightly off of the distal border of the thenar muscle.
A Miltex retractor is positioned in the wrist. The superficial palmar fascia is incised in line with its fibers and the retractor is placed deeper into the wound (Fig. 12-7). A Ragnell retractor is placed in the distal aspect of the incision. The soft tissue is spread to identify the fat, which pouches up at the distal aspect of the transverse carpal ligament. Distal and proximal tissues are retracted until at least one third of the distal transverse carpal ligament can be visualized. The ligament is then incised for a distance of 1 cm. The distal end of the ligament is cut until the fat overlying the superficial palmar arch is exposed. The contents of the carpal tunnel, including the median nerve, can now be identified and protected throughout the remainder of the operation (Fig. 12-8).
A smooth blunt pilot instrument is then placed proximally between the underside of the transverse carpal ligament and the carpal tunnel contents (Fig. 12-9). The instrument is withdrawn and a palmar stripper is then placed under the ligament and into the wound under direct visualization. This sharp instrument is designed to prepare a channel through the thick connecting tissues directly palmar to the ligament. The stripper is inserted into the groove that was formed by the distal division of the ligament and pushed proximally until resistance is felt. The design of the instrument prevents it from penetrating the ligament. The stripper is removed and a double pilot instrument is introduced. This instrument, with long, dull lower and upper skids, allows for full visualization of the passageway beneath the ligament. It provides an area for the cutting "tome" to enter and allows for safe passage above and below the transverse carpal ligament. The pilot is removed and the "tome" guide is
Figure 12—9. The blunt pilot is placed in the depths of the wound between the underneath surface of the transverse carpal ligament and the contents of the carpal canal.
inserted between the undersurface of the transverse carpal ligament and the carpal tunnel contents. To allow for complete division of the transverse carpal ligament, the "tome" guide is placed proximally.
The patient's wrist is fully hyperextended and positioned in a neutral alignment. The cutting "tome" is inserted into the prepared ligament and passed proximally (Fig. 12—10). The cutting "tome" should not be reintroduced after the primary ligament transection. The cutting "tome" is removed and the contents of the carpal tunnel can be inspected (Fig. 12-11).
The skin is closed and a soft dressing is applied to the palm and wrist (Fig. 12-12). Digital range-of-motion and tendon gliding exercises are taught to the patient in the operating room. The patient returns in 2 weeks for suture removal.
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