Open Surgery for Treatment of Instability
Seven patients had nerve injury resulting from an open surgical procedure to treat shoulder instability (Table I). All patients had a general anesthetic, and two received an additional suprascapular nerve block. Three patients had an injury at the level of the brachial plexus (two in the upper trunk and one at the cord level) and four, at a terminal nerve branch (three of the axillary nerve and one combined injury of the axillary and radial nerves). There were four structural nerve injuries, with the nerves entrapped by sutures passed through the capsule in all instances (see Appendix). The medial, lateral, and posterior cords of the brachial plexus were sutured in one instance; the axillary nerve was sutured in two cases; and the radial and axillary nerves were involved in one case.
Five of the seven patients required surgery to remove the incarcerating suture, followed by nerve repair, nerve grafting with sural nerve grafts, and/or subsequent tendon transfers to restore hand function.
Four patients in this group were followed for more than one year. One of them had a minor deficit (numbness of the superficial branch of the radial nerve), and the other three had substantial motor and/or sensory deficits.
Nine patients had nerve injury secondary to arthroscopic procedures (Table II). In addition to general anesthesia, four patients had a suprascapular nerve block. Two procedures were performed with the patient in the lateral position with traction and the remainder, with the patient in a beach-chair position. Three patients had an injury at the level of the brachial plexus (the upper trunk in two and the cord level in one) and six, at a terminal nerve branch (axillary nerve in three, axial and radial nerve in one, radial nerve in one, and median nerve in one). Five of the nine patients had surgical treatment of the nerve injuries. Two of them had nerve transfers, one was treated with nerve graft, one had a tendon transfer for median nerve function, and one had an unrepairable nerve lesion secondary to injury at the neuromuscular junction with severe pain and underwent a proximal axillary neuroma excision. There were two cases of structural nerve damage during an arthroscopic Bankart repair: the anterior division of the axillary nerve was sutured in one patient (see Appendix), and the axillary nerve was lacerated in the other. In the latter patient, the nerve was lacerated at the neuromuscular junction near the posterior portal.
Four patients underwent conservative treatment (observation). Three of them had presented for evaluation more than twelve months after injury; had residual ulnar, median, and/or musculocutaneous nerve deficits; and were advised that nerve surgery would not be of benefit secondary to the time that had elapsed since the injury. All chose to be observed. The remaining patient had a radial nerve palsy that resolved by two months after surgery.
Of the nine patients, only one made a full recovery; the remaining eight had debilitating motor/sensory deficits.
Combined Open and Arthroscopic Procedures
Six patients had nerve injury resulting from a combined procedure (Table III). The arthroscopic portions included diagnostic arthroscopy, subacromial decompression, and debridement or repair of the rotator cuff. The open portion was a subpectoral biceps tenodesis in five cases; in the remaining patient, a cyst was excised from the supraspinatus muscle in combination with a distal clavicle excision. In addition to a general anesthetic, two patients received regional nerve blocks. Three patients had an injury to the brachial plexus, and three had a terminal nerve branch injury. A structural nerve injury occurred in three cases.
The open procedure was responsible for three of the nerve injuries. Two nerve lacerations were caused by an open subpectoral biceps tenodesis: the musculocutaneous nerve was lacerated in the region of the tenodesis screw (see Appendix) in one of these cases, and the median nerve was mistaken for the biceps tendon and was stitched and tenodesed into the humerus in the other patient. The third laceration, which involved the suprascapular nerve, occurred during the excision of a cyst from the supraspinatus. We could not ascertain if the nerve injury was secondary to the open or the arthroscopic procedure in three patients treated with a combined procedure.
Four of the six patients required surgical management, and surgery would have been considered for one other patient if she had presented before developing fixed contractures of the hand. Surgery consisted of tendon transfers in one patient, nerve transfers in two, and nerve grafting in one. Four patients had more than one year of follow-up; one made a full recovery, and the other three had substantial functional impairment.
Four patients had nerve injuries following a total shoulder arthroplasty (Table IV). In addition to general anesthesia, there were two regional nerve blocks. All of the injuries involved the brachial plexus. There were no structural nerve injuries. One patient required an Eden-Lange tendon transfer because of persistent scapular winging. Three patients were followed for more than a year; one made a full recovery, and the other two had limited shoulder function.
Time to Presentation
The average time between the injury and evaluation was 5.4 months (range, one to fifteen months; median, five months) in the series overall. In three patients, the clinical outcome was compromised specifically because of treatment delay. These individuals presented at eight, ten, and eighteen months after their injury. In two patients, the opportunity for nerve transfers had been lost. In the third patient fixed contractures of the fingers had developed, prohibiting tendon transfers.
Distribution of Severe Injuries
The percentage of patients who had a structural nerve injury or who required surgical intervention varied according to the location of the nerve injury (see Appendix). Individuals presenting with an isolated lesion of a terminal nerve branch were more likely to have a structural nerve injury than patients who had an injury to the brachial plexus. Patients with a terminal nerve branch injury had spontaneous recovery less often and underwent surgical reconstruction more often than those with a brachial plexus injury.
The percentage of patients who sustained a structural injury or required surgical treatment also varied according to the type of index surgery (Fig. 2). The rates of structural injuries and surgical intervention were higher in patients who had undergone an open operation for instability or combined arthroscopic and open operations.
Patients who have neurologic symptoms following a shoulder surgical procedure may have a severe underlying neurologic injury that could result in permanent deficits. These events can occur after any type of shoulder procedure and may result from several potential injury mechanisms. All patients with postoperative neurologic symptoms should be evaluated with a high index of suspicion to avoid a delay in treatment. Patients who have a complete deficit of a peripheral nerve have a higher likelihood of having a structural nerve injury.
In this series, neurologic injuries resulted from a wide array of shoulder procedures. Some occurred during operations that are already recognized as having a risk for nerve injury, such as open procedures for instability and shoulder arthroplasties1,2,10. Other injuries were sustained during situations that have not been previously reported, and perhaps are not perceived, as being as susceptible to a neurologic injury, such as subpectoral biceps tenodesis and arthroscopic Bankart repair. These cases demonstrate that patients who present with a neurologic deficit following a shoulder operation must be closely followed and evaluated since they may have a permanent injury even if the perceived risk is low. The best example of this is isolated arthroscopic procedures; the risk of neurologic injury has been reported to be as low as 0.1% and there are very few reports of permanent neurologic deficits3,5,6,9. Yet five patients in our series had functional deficits at more than one year following shoulder arthroscopy.
Although severe injuries can occur in any setting, their likelihood appears to be higher in certain scenarios. Structural nerve injuries such as lacerations or suture entrapment most often occur when neurologic structures are in close proximity to the operative field while sutures are being placed or structures are divided. For instance, the musculocutaneous, median, and ulnar nerves are at risk during a subpectoral biceps tenodesis; the entire brachial plexus and axillary nerve, during an open operation for instability; and the axillary nerve, during an arthroscopic Bankart repair. Furthermore, a structural injury must be considered if a patient presents with a complete palsy of an isolated peripheral nerve. In contrast, stretch injuries resulting from retraction, such as occurs in shoulder arthroplasty, usually produce incomplete deficits of multiple nerves or a portion of the plexus. This is more likely when the involved nerves were not directly within the operative field, such as in a patient with an incomplete palsy of both cord levels of the brachial plexus affecting the ulnar and radial nerves following a total shoulder arthroplasty. Finally, we have observed that patients with suture entrapment injuries present with excruciating neuropathic pain in addition to loss of motor function immediately postoperatively.
The nerve injuries in this series were the result of multiple causes. Some patients had a structural nerve injury, and in those cases the mechanism of injury could often be clearly defined. In the remaining patients, the injuries had many potential causes. In open surgery, retractors placed anterior to the subscapularis or medial to the glenoid can injure the brachial plexus, which is located just 10 to 25 mm medial to the glenoid11. Arm positioning also places strain on the brachial plexus, and intraoperative neuromonitoring studies have demonstrated that nerve dysfunction may occur with extreme positions of the shoulder during arthroplasties and during arthroscopic procedures with the patient in the lateral position when traction is applied12-14. Complications of regional anesthesia are also possible but are likely very rare. It is estimated, on the basis of two large prospective studies, that neurologic injury results from three of 10,000 peripheral nerve blocks15-17. Furthermore, nearly two-thirds of the patients in this series had not had a block performed.
Regardless of the perceived cause of injury, it is important that patients with postoperative neurologic deficits be thoroughly and promptly evaluated. In this series, there was often a lengthy delay between the time of injury and referral for evaluation by a peripheral nerve surgeon. The average time lapse was 5.4 months. This is a very important point because the treatment options available to these patients are time-sensitive. Following a nerve injury, irreversible changes occur at the motor end plate in a time-dependent manner so that reinnervation procedures are most successful if they are performed before six months18. Furthermore, early referral allows the patient to have serial physical examinations and EMGs, which enables the treating surgeon to gauge recovery and assess the need for surgery. We recommend obtaining the first EMG at six weeks postinjury and serially thereafter.
We recognize the limitations of this study, which include its retrospective nature and the biases that are inherent to retrospective studies. Additionally, we have a very specialized referral practice, and the referral bias may reflect more severe injuries. We also recognize that a large majority of nerve injuries associated with shoulder surgery are neurapraxias and often resolve spontaneously. However, despite these limitations, serious nerve injuries do occur, cannot be ignored, and cannot always be attributed to neurapraxia.
In conclusion, although nerve injuries after shoulder surgery are relatively uncommon, severe neurologic injuries can occur. Severe injuries resulting from shoulder surgery are more commonly direct nerve injuries caused by either laceration or suturing and tend to be isolated terminal nerve branch injuries. These injuries may require surgical management and can result in permanent disability. Lengthy delays in evaluation can compromise the final outcome. When evaluating a postoperative neurologic deficit following shoulder surgery, surgeons should maintain a high index of suspicion for nerve injuries that will not resolve spontaneously and may require timely surgical management.
A table showing the BMRC muscle grading system and figures demonstrating individual cases are available with the online version of this article as a data supplement at jbjs.org.
Investigation performed at the Mayo Clinic, Rochester, Minnesota
1. Ho E Cofield RH Balm MR Hattrup SJ Rowland CM. Neurologic complications of surgery for anterior shoulder instability. J Shoulder Elbow Surg. 1999 May-Jun;8(3):266–70.
2. Lynch NM Cofield RH Silbert PL Hermann RC. Neurologic complications after total shoulder arthroplasty. J Shoulder Elbow Surg. 1996 Jan-Feb;5(1):53–61.
3. Rodeo SA Forster RA Weiland AJ. Neurological complications due to arthroscopy. J Bone Joint Surg Am. 1993 Jun;75(6):917–26.
4. Segmüller HE Alfred SP Zilio G Saies AD Hayes MG. Cutaneous nerve lesions of the shoulder and arm after arthroscopic shoulder surgery. J Shoulder Elbow Surg. 1995 Jul-Aug;4(4):254–8.
5. Small NC. Complications in arthroscopic surgery performed by experienced arthroscopists. Arthroscopy. 1988;4(3):215–21.
6. Small NC. Complications in arthroscopic surgery of the knee and shoulder. Orthopedics. 1993 Sep;16(9):985–8.
7. Stanish WD Peterson DC. Shoulder arthroscopy and nerve injury: pitfalls and prevention. Arthroscopy. 1995 Aug;11(4):458–66.
8. Boardman ND 3rd Cofield RH. Neurologic complications of shoulder surgery. Clin Orthop Relat Res. 1999 Nov;(368):44–53.
9. Marecek GS Saltzman MD. Complications in shoulder arthroscopy. Orthopedics. 2010 Jul;33(7):492–7.
10. Richards RR Hudson AR Bertoia JT Urbaniak JR Waddell JP. Injury to the brachial plexus during Putti-Platt and Bristow procedures. A report of eight cases. Am J Sports Med. 1987 Jul-Aug;15(4):374–80.
11. McFarland EG Caicedo JC Guitterez MI Sherbondy PS Kim TK. The anatomic relationship of the brachial plexus and axillary artery to the glenoid. Implications for anterior shoulder surgery. Am J Sports Med. 2001 Nov-Dec;29(6):729–33.
12. Esmail AN Getz CL Schwartz DM Wierzbowski L Ramsey ML Williams GR Jr. Axillary nerve monitoring during arthroscopic shoulder stabilization. Arthroscopy. 2005 Jun;21(6):665–71.
13. Pitman MI Nainzadeh N Ergas E Springer S. The use of somatosensory evoked potentials for detection of neuropraxia during shoulder arthroscopy. Arthroscopy. 1988;4(4):250–5.
14. Nagda SH Rogers KJ Sestokas AK Getz CL Ramsey ML Glaser DL Williams GR Jr. Neer Award 2005: Peripheral nerve function during shoulder arthroplasty using intraoperative nerve monitoring. J Shoulder Elbow Surg. 2007 May-Jun;16 (3)(Suppl):S2–8. Epub 2006 Jul 26.
15. Auroy Y Benhamou D Bargues L Ecoffey C Falissard B Mercier FJ Bouaziz H Samii K. Major complications of regional anesthesia in France: The SOS Regional Anesthesia Hotline Service. Anesthesiology. 2002 Nov;97(5):1274–80.
16. Auroy Y Narchi P Messiah A Litt L Rouvier B Samii K. Serious complications related to regional anesthesia: results of a prospective survey in France. Anesthesiology. 1997 Sep;87(3):479–86.
17. Brull R McCartney CJ Chan VW El-Beheiry H. Neurological complications after regional anesthesia: contemporary estimates of risk. Anesth Analg. 2007 Apr;104(4):965–74.
18. Shin AY Spinner RJ Steinmann SP Bishop AT. Adult traumatic brachial plexus injuries. J Am Acad Orthop Surg. 2005 Oct;13(6):382–96.
Disclosure: None of the authors received payments or services, either directly or indirectly (i.e., via his or her institution), from a third party in support of any aspect of this work. One or more of the authors, or his or her institution, has had a financial relationship, in the thirty-six months prior to submission of this work, with an entity in the biomedical arena that could be perceived to influence or have the potential to influence what is written in this work. No author has had any other relationships, or has engaged in any other activities, that could be perceived to influence or have the potential to influence what is written in this work. The complete Disclosures of Potential Conflicts of Interest submitted by authors are always provided with the online version of the article.Copyright 2013 by The Journal of Bone and Joint Surgery, Incorporated