Medical Therapy
Conservative treatment of intersection syndrome includes immobilization, activity modification, and pharmacologic intervention. The radial wrist extensors can be immobilized with a cock-up wrist splint (20º of extension). Because of secondary irritation by the abductor pollicis longus (APL) and extensor pollicis brevis (EPB), a thumb spica splint (allowing thumb interphalangeal [IP] motion) is frequently required.
Three weeks of relatively constant immobilization, followed by gradual splint weaning, usually is recommended. Activity modification at home or work is also critical. [22]
Oral nonsteroidal anti-inflammatory drugs (NSAIDs) may decrease inflammation. A 2-mL injection of 1% lidocaine/betamethasone directly into the area of swelling may be effective in recalcitrant cases. A short course of oral steroids may be needed.
Once the most severe symptoms are under control, a program of supervised hand or occupational therapy leads to long-term recovery. This may include tendon stretching, ultrasound, and thermal modalities, followed by secondary strengthening and activities of daily living (ADL) modification or essential job task retraining.
Successful treatment of intersection syndrome using pulsed Nd:YAG laser theapy has been reported. [23]
Surgical Therapy
Surgery can be effective in cases of intersection syndrome that do not respond to conservative measures. [24]
Intraoperative Details
The second extensor compartment is approached through a dorsal longitudinal incision, beginning over the area of swelling and continuing distally 3-4 cm. Bluntly dissect down to the dorsal forearm fascia and divide longitudinally. Protect major veins and, particularly, branches of the radial sensory nerve that are located in this region. Completely mobilize the extensor carpi radialis longus (ECRL) and extensor carpi radialis brevis (ECRB) tendons by longitudinally incising the extensor retinaculum over the second compartment.
A bursa also may form between the overlying APL and EPB tendons. When present, this bursa should be resected.
Perform a thorough tenosynovectomy while elevating and protecting the tendons. This also may require mobilization of the EPB and APL, which then are retracted proximally and distally to provide complete access to the second compartment. The extensor retinaculum is not repaired. Skin is closed in routine fashion.
Postoperative Details
Immobilize the area in a compressive dressing and well-padded volar thumb spica splint, maintaining the wrist at 20º of extension for 7-10 days.
Follow-up
At the first postoperative visit, place the patient in a removable splint and encourage early wrist range-of-motion (ROM) exercises. Some patients require postoperative therapy similar to that used prior to surgery.
Occupational therapy generally is initiated early for patients with labor-intensive occupations. The goals of therapy are strengthening, full ROM, and modification of equipment. The rehabilitation period may last 4-6 weeks.
Complications
Cortisone injections near the skin may cause depigmentation in patients who are dark skinned. These injections also may lead to subcutaneous fat atrophy or necrosis, infection, and tendon rupture, although, fortunately, these complications are rare.
Theoretically, surgical release of the extensor retinaculum could lead to bowstringing of the tendons in extreme wrist extension. However, this potential problem has not been reported.
Outcome and Prognosis
Most patients with intersection syndrome respond to a program of conservative management. They may need to maintain changes in work or avocational activities to prevent recurrence of symptoms. Individuals who require surgery rarely experience recurrence of symptoms.
No large series documenting treatment outcome exist in the literature. Eight patients in one study all responded to immobilization and corticosteroid injection. Grundberg and Reagan state that about 60% of patients in their practice with intersection syndrome respond to conservative management. [13] They report that 100% of their patients who require surgery obtain long-term symptomatic relief. In the author's experience, nonoperative treatment of intersection syndrome is successful in approximately 75% of cases; surgical decompression of the second extensor compartment is effective in the remainder of patients.
Future and Controversies
The major controversies surrounding intersection syndrome pertain to diagnosis and pathophysiology. The examining physician must be convinced that the patient's wrist or forearm pain is not due to inflammation or compression of other radial-sided structures, such as the flexor carpi radialis (FCR), tendons of the first extensor compartment, thumb CMC joint, or radial sensory nerve. Obviously, location of corticosteroid injection or surgical management would differ greatly for these other conditions.
In academic circles, some disagreement exists as to the exact location of tenosynovitis—whether it solely involves the second extensor compartment or represents an abnormal interaction between the tendons of the first and second compartments. While one's belief could affect choice of immobilization (cock-up wrist splint versus thumb spica splint), injection therapy and surgical release would not be altered.
