Persistent and Profound Peripheral Nerve Injuries Following Reverse Total Shoulder Arthroplasty

These authors point out that peripheral nerve injuries associated with reverse total shoulder arthroplasty (rTSA) are uncommonly recognized and are often dismissed as neuropraxias, particularly in the setting of perioperative nerve blocks.

They conducted a retrospective review of 22 patients referred to a nerve injury service who had undergone rTSA and had a concomitant major nerve injury. The average time from surgery to referral to a nerve injury practice was 9.0 months.

Injury patterns were variable and involved diffuse pan-plexopathies with severity localized to the posterior and medial cords (11), the upper trunk (5), lateral cord (2) and axillary nerve (4).

The average postoperative acromiohumeral distance (AHD) was 3.7 cm with an average change of 2.9 cm.

17 patients were confirmed to have undergone preoperative nerve blocks, which were initially attributed as the etiology of nerve injury.

18 patients were initially treated with observation: 11 experienced residual debilitating neuropathic pain and/or disability and 7 had substantial improvement.

Complete axillary nerve injury was seen in 4 patients, of which none resolved spontaneously. Patients with upper trunk or lateral cord injuries spontaneously resolved over the course of their 18.8 month follow-up. There were 13 cord level injuries of which 11 were medial/posterior cord combined injuries. These were the most serious, especially the medial cord injuries which severely affected hand function via ulnar nerve injury. Of these 11 posterior/medial cord injuries, all had altered ulnar nerve function with loss of intrinsic function, thumb adduction and digital flexion with altered ulnar nerve sensation. Four of the 11 required reconstructive hand surgery to improve their pattern of grasp. All 11 had disabilities consistent with permanent ulnar nerve dysfunction as evidenced by their high Quick DASH scores and need for neuropathic medications.

The authors concluded that these nerve injuries were secondary to traction at the time of arthroplasty, and/or substantial distalization and lateralization of the implants.

Comment: One of the important lessons from this study is that the use of nerve block anesthesia may prevent the surgeon from promptly recognizing a postoperative nerve injury and eliminate the possibility of prompt intervention. A second lesson is that these nerve injuries can be long lasting and disabling in terms of pain and loss of function. A third lesson is that the average distalization of the humerus in these cases was 2.9 cm. While there is not a comparison group of measurements in reverses without nerve injuries, it seems likely that distalization can result in a traction injury to the nerves of the plexus as explained nicely in this link.

The nerve injuries reported in this article were major. It seems likely that many less severe injuries occur in association with reverse total shoulder arthroplasty and that these injuries might account for compromised deltoid function as well as postoperative pain.

While some surgeons prefer substantial distalization (below left), our technique (see this link) strives for a more anatomic reconstruction with only a small amount of distalizalization and less tension on the nerves (below right). We also avoid brachial plexus blocks on our patients having shoulder arthroplasty so that a complete examination can be documented in the recovery room.