CHAPTER SYNOPSIS:

Wrist arthrosis can cause debilitating pain that is difficult to treat. Many operations are available to treat this condition, such as proximal row carpectomy or limited or complete arthrodesis of the wrist; however, these surgeries entail loss of motion and require significant recovery time. Denervation of the wrist may be a good alternative in patients who are not candidates for these procedures or who cannot afford to lose motion or spare the time to recuperate from larger surgical interventions.

IMPORTANT POINTS:

Innervation of the wrist is anatomically variable between individuals.

Wrist innervation has contributions from the median nerve (anterior interosseous and palmar cutaneous branches); radial nerve (posterior interosseous and superficial cutaneous branches); ulnar nerve (branches from the main trunk, dorsal cutaneous branch, and the deep branch); and posterior, lateral, and medial antebrachial cutaneous nerves.

Indications for this procedure are debilitating wrist pain in elderly patients with low-demand wrists, wrist arthrosis in patients who do not desire larger surgeries associated with long recovery periods and loss of motion, wrist pain not amenable to other surgical interventions, or continued wrist pain after a salvage operation. Additionally, there must be useful motion of the wrist without significant chronic inflammation.

CLINICAL/SURGICAL PEARLS:

Partial denervation can be performed with one or two incisions and typically involves transection of the posterior and anterior interosseous nerves.

Complete wrist denervation requires four to five incisions and addresses sensory contributions from the median, radial, and ulnar nerves.

Pain relief is variable and gradual over 18 months.

Preoperative nerve blocks can be used to predict surgical outcomes but may overestimate degree of pain relief.

No Charcot joints have been reported from this operation probably because the contributions of sensation from multiple nerves prevent complete surgically induced anesthesia of the wrist.

CLINICAL/SURGICAL PITFALLS:

Patients must be alerted to the fact that pain relief is not universal for these procedures and that they should not expect immediate relief but rather gradual relief. Complications from the surgical procedure itself are uncommon.

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INTRODUCTION

Arthrosis of the wrist can cause debilitating pain that is difficult to treat. Numerous surgical procedures have been described to treat arthrosis of the wrist such as proximal row carpectomy and limited and complete arthrodesis of the wrist. These procedures, however, not only have significant recovery periods, but also are associated with loss of motion and possibly loss of strength, making them less than ideal for certain patients.

An ideal surgical procedure would eliminate or greatly reduce pain in the wrist while preserving both motion and strength. In an attempt to achieve these goals, Wilhelm first described the procedure of complete denervation of the wrist in the mid 1960s. He reported promising results on 21 patients who underwent denervation for scaphoid nonunions and Kienböck’s disease. Since that time, indications for denervation procedures of the wrist have been expanded and, although the procedure is still not widespread, it is a good option for well-selected patients with pain and arthrosis of the wrist.

Early reports of wrist denervation focused on “complete” denervation and typically advocated four or five incisions that divided contributions to wrist sensation from medial, ulnar, and radial nerves and medial, lateral, and posterior antebrachial cutaneous nerves. More recently in the literature, however, some authors have advocated for a “limited” denervation through one or two incisions that divide the anterior and posterior interosseous nerves.

INDICATIONS/CONTRAINDICATIONS

The typical patient being considered for wrist denervation should have moderate to severe arthrosis of the wrist with significant and functionally limiting pain. The patient’s wrist pathology should not be amenable to an operation that will preserve motion and strength while preventing further deterioration of the condition of the wrist. Additionally, the patient should have a functional range of motion of the wrist and the absence of significant inflammatory wrist disease.

The first category of patients that fits these criteria and will benefit from a wrist denervation procedure consists of older, low-demand patients. These patients can expect to have reasonable and long-lasting pain relief despite significant radiographic pathology. In other words, the need for subsequent salvage procedures is unlikely.

The second category of patients that may benefit from this procedure includes those in whom arthrodesis or loss of motion would be functionally limiting or would interfere with their occupation. It may also include those who cannot afford the prolonged recovery period of a larger more definitive salvage operation on the wrist. These patients may achieve good, but more temporary, results. The continued high stresses placed on the diseased wrist in these more active patients typically lead to progressive deterioration of both the joint and the pain relief. These patients should be counseled that the salvage procedure can be postponed but probably not indefinitely.

The third group of patients is the atypical group that has ongoing debilitating pain despite lack of identifiable “pain generators.” Included in this group are those who have already undergone a technically successful but clinically unsatisfactory salvage procedure. These patients continue to have pain despite surgical elimination of the arthritic areas. Also in this category are those who present as if they have arthritis, yet no or minimal arthritic changes can be identified radiographically or arthroscopically. Results with these patients will be more variable but may offer some relief without the increased morbidity of a more aggressive yet unpredictable surgery.

In fact, there are no absolute contraindications to this procedure. Patients who do not have useful range of motion of their wrist, those with debilitating inflammation of the wrist, and those with severe arthrosis will probably have a better outcome proceeding directly to a salvage type procedure. Additionally, patients with marked posttraumatic arthritis secondary to displaced intraarticular distal radius fractures, scaphoid nonunion advance collapse (SNAC), or carpal instability (scapholunate advance collapse, or SLAC) may not benefit from a denervation procedure because of the progressive nature of their pathology.

ANATOMY

Understanding the anatomy of wrist innervation is essential to planning and executing a successful denervation procedure. This innervation has been well studied by many authors, and the results of their studies have shown that nerve anatomy of the wrist capsule is redundant and not constant among individuals. This means that surgical denervation procedures do not result in complete anesthesia of the wrist and are not universally successful. The upside of this neural anatomy is that a completely anesthetic wrist might be prone to Charcot joint formation, which surgically denervated wrists do not seem to be.

The wrist, like most other joints, has both primary and accessory innervation. Primary innervation or direct capsular innervation comes only from the terminal branch of the posterior interosseous nerve (PIN). The wrist, however, receives accessory innervation from the radial, ulnar, and median nerves and the lateral, medial, and posterior antebrachial cutaneous nerves.

Median Nerve

The median nerve contributions to the wrist joint include branches of both the anterior interosseous nerve (AIN) and palmar cutaneous nerve (PCN). In the distal forearm, the AIN travels on the anterior surface of the interosseous membrane. On average, four motor branches to the pronator quadratus originate between 2.4 and 3.8 cm proximal to the ulnar head. The AIN then terminally arborizes into the periosteum of the distal radius and the proximal end of the palmar radiocarpal ligaments ( Fig. 3-1 ). An additional branch to the distal radioulnar joint has been reported to occur in 17% to 40% of specimens.

Innervation of the palmar aspect of the wrist joint. Overall course of the nerves is depicted and not necessarily nerve endings. 1: AIN. 2: PCN. 3: LABC.

(From Van de Pol GJ, Koudstaal MJ, Schuurman AH, et al: Innervation of the wrist joint and surgical perspectives of denervation. J Hand Surg 2006;31A. Used with permission.)

The PCN travels in the subcutaneous tissue after piercing the antebrachial fascia. At the level of the radial styloid, a branch tunnels back through the transverse carpal ligament adjacent to the tubercle of scaphoid and innervates the joint ( Fig. 3-1 ). The consistency of this particular branch, however, is subject to some controversy because its presence has not been noted by several investigators.

Radial Nerve

After giving off several motor branches, the PIN continues along the posterior aspect of the interosseous membrane and through the fourth extensor compartment either within the radial wall of the compartment or along the radial aspect of the floor. It will typically give one articular branch to the radiocarpal joint and then continue before dividing into three or four terminal branches supplying the midcarpal joint and the second, third, and fourth carpometacarpal joints ( Fig. 3-2 ).

Innervation of the dorsal aspect of the wrist joint. 4: PIN. 5: DBUN. 6: SBR.

(From Van de Pol GJ, Koudstaal MJ, Schuurman AH, et al: Innervation of the wrist joint and surgical perspectives of denervation. J Hand Surg 2006;31A. Used with permission.)

The radial nerve also provides some accessory innervation to the wrist capsule. The superficial branch of the radial nerve (SBR) typically gives a branch to the first intermetacarpal space. This branch supplies innervation to the first and second carpometacarpal joints. The SBR occasionally gives an additional articular branch to the radiocarpal joint. This branch, however, more commonly terminates in the extensor retinaculum ( Fig. 3-2 ).