CRPS Type 2 may develop after surgery because of nerve compression

[mtomaino]

The development of severe pain, excessive swelling,and stiffness after upper-extremity surgery should alert the surgeon to possible development of chronic regional pain syndrome. Complex regional pain syndrome (CRPS)—previously known as algodystrophy,
reflex sympathetic dystrophy (RSD), causalgia, Sudeck’s atrophy, sympathalgia, shoulder-hand syndrome,posttraumatic pain syndrome, and neurodystrophy—was defined at the American Pain Meetingin 19931 as (1) a syndrome that develops after an
initial noxious event; (2) spontaneous pain and/orallodynia/hyperalgesia not limited to the territory of asingle peripheral nerve and disproportionate to the
inciting event; (3) evidence of edema, skin bloodflow abnormality, or abnormal sudomotor activity;and (4) a diagnosis that is excluded by the existenceof other conditions that would account for the degreeof pain and dysfunction.

Complex regional pain syndrome is a clinical diagnosis and may be subdivided
into 2 types based on etiology: type I CPRS is precipitated by a noxious event whereas type II CRPS isrelated to a peripheral nerve injury. Nerve compression after surgery falls into the category of CRPS Type 2.

Several investigations have evaluated the relationship between nerve compression and CRPS. Monsivais et al (J Hand Surg 1993;18B:337–338) showed that 30 of 35 patients presenting with RSD had compression of 1 or more peripheral nerves. Fifteen patients had a single nerve compression and the remainder had compression of 2 or more
nerves. Of these patients 70% had median nerve compression, 47% had ulnar nerve compression atthe elbow, 37% had posterior interosseous nerve compression at the elbow, 6% had ulnar nerve compression at the wrist, and 3% had superficial radial
nerve entrapment at the wrist.

Grundberg and Reagan ( J Hand Surg 1991;16A:731– 736) showed that 29 of 93 cases of RSD that were resistant to conventional treatments had clinical and electrophysiologic evidence of peripheral nerve compression. After peripheral nerve decompression (22 at carpal tunnel, 5 at cubital tunnel, 1 at Guyon’s canal, 1 herniated disk) all patients reported an improvement in pain, swelling, range of motion, and strength.

Despite these reports the importance of a thorough neurologic examination to evaluate for nerve compression in the setting of CRPS remains underappreciated. However, in the setting of clinical and electrophysiologic evidence of nerve
compression, Gelberman and co-authors showed that surgical intervention may hasten recovery in these patients. (J Hand Surg 2005;30A:69–74.

So----what does this mean?

If you have had surgery, and still have pain and/or stiffness and swelling, it's worth making sure there is no clinical or electrodiagnostic evidence of nerve entrapment. When it comes to the upper extremity, this means ruling out carpal or cubital tunnel syndrome, as well as suprascapular nerve entrapment at the supraglenoid notch. As the investigators above have shown, nerve decompression may be efficacious in such cases.