Axillary nerve monitoring during arthroscopic shoulder stabilization.
ABSTRACT This study evaluated the ability of a novel intraoperative neurophysiologic monitoring method used to locate the axillary nerve, predict relative capsule thickness, and identify impending injury to the axillary nerve during arthroscopic thermal capsulorrhaphy of the shoulder.
Prospective cohort study.
Twenty consecutive patients with glenohumeral instability were monitored prospectively during arthroscopic shoulder surgery. Axillary nerve mapping and relative capsule thickness estimates were recorded before the stabilization portion of the procedure. During labral repair and/or thermal capsulorrhaphy, continuous and spontaneous electromyography recorded nerve activity. In addition, trans-spinal motor-evoked potentials of the fourth and fifth cervical roots and brachial plexus electrical stimulation, provided real-time information about nerve integrity.
Axillary nerve mapping and relative capsule thickness were recorded in all patients. Continuous axillary nerve monitoring was successfully performed in all patients. Eleven of the 20 patients underwent thermal capsulorrhaphy alone or in combination with arthroscopic labral repair. Nine patients underwent arthroscopic labral repair alone. In 4 of the 11 patients who underwent thermal capsulorrhaphy, excessive spontaneous neurotonic electromyographic activity was noted, thereby altering the pattern of heat application by the surgeon. In 1 of these 4 patients, a small increase in the motor latency was noted after the procedure but no clinical deficit was observed. There were no neuromonitoring or clinical neurologic changes observed in the labral repair group without thermal application. At last follow-up, no patient in either group had any clinical evidence of nerve injury or complications from neurophysiologic monitoring.
We successfully evaluated the use of intraoperative nerve monitoring to identify axillary nerve position, capsule thickness, and provide real-time identification of impending nerve injury and function during shoulder thermal capsulorrhaphy. The use of intraoperative nerve monitoring altered the heat application technique in 4 of 11 patients and may have prevented nerve injury.
Level II, prospective cohort study.
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ABSTRACT: Twelve right shoulders in fresh cadavers were dissected to determine the relation of the axillary nerve to the shoulder capsule and glenoid. Needles transfixed the nerve to the capsule and into the shoulder joint. Arthroscopy was performed to determine the location of the needles on the glenoid clock. The needles were then removed and the position of the shoulder changed to determine the effect on the position of the axillary nerve. The axillary nerve was held to the shoulder capsule with loose areolar tissue in the zone between 5 and 7 o'clock and was close to the glenoid in the neutral position, in extension, and in internal rotation. With shoulder abduction, external rotation, and perpendicular traction, the capsule became taut and the axillary nerve moved away from the glenoid. Abduction, external rotation, and perpendicular traction increase the zone of safety during arthroscopic anteroinferior capsulotomy adjacent to the glenoid between the 5 and 7 o'clock positions.Journal of Shoulder and Elbow Surgery 01/1999; 8(3):226-30. · 2.32 Impact Factor
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ABSTRACT: Two-hundred eighty-two patients underwent anterior reconstruction for recurrent glenohumeral instability between 1981 and 1991. Twenty-three patients (8.2%) had a neurologic deficit after surgery. Seven had sensory disturbances only; 16 had sensorimotor neuropathies (8 having multiple deficits designated as a diffuse plexopathy and 8 having a more defined deficit in 1 or 2 cords or peripheral nerves). Complete resolution occurred in 18 of the 23 patients. Four patients had a residual deficit (1 patient was lost to follow-up). Three had persistent sensory disturbances; 1 had permanent biceps weakness. None of these patients underwent surgical exploration. Older age (P = .045) and a Bankart lesion (P = .029) were associated with a neurologic complication. At an average follow-up of 8.7 years, 252 patients responded to a questionnaire regarding shoulder outcome, including 20 of the 23 patients with nerve injuries. The difference in the median Rowe score of those with and without nerve injury was not significant (P = .072). Neurologic injuries after anterior shoulder surgery presumably arise as a result of traction. The prognosis for neurologic recovery is generally good. Neurologic injury did not interfere with the outcome of the stabilization procedure.Journal of Shoulder and Elbow Surgery 01/1999; 8(3):266-70. · 2.32 Impact Factor
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ABSTRACT: Capsulorrhaphy of the glenohumeral joint is a common surgical procedure for the treatment of instability caused by increased capsular laxity. The effect of capsulorrhaphy on the range of motion of the shoulder is poorly understood. We simulated localized capsular contractures by selective capsular plications in eight human cadaveric shoulders and studied the effect of such plications on the passive range of glenohumeral abduction, flexion, and external and internal rotation in different degrees of abduction. A 0.5 or 1-N-m torque was applied to the humerus, and the range of glenohumeral motion was measured with electronic goniometers in three planes and compared with those of the intact shoulder. Anterosuperior capsular plication most markedly affected external rotation of the adducted arm, decreasing it by a mean of 30.1 degrees (p < 0.0001). Anteroinferior plication significantly reduced abduction by a mean of 19.4 degrees (p < 0.0001) and external rotation by a mean of 20.6 degrees (p = 0.0046). Posterosuperior plication mostly limited internal rotation of the adducted arm (mean decrease, 16.1 degrees, p = 0.0045). On the average, total anterior and total posterior plication each limited flexion by approximately 20 degrees (p = 0.005) and abduction by >or=15 degrees (p < 0.005), whereas total anterior plication limited external rotation by >30 degrees (p <or= 0.0002) and total posterior plication limited internal rotation by >20 degrees (p < 0.0001). Total inferior capsular plication restricted abduction (by a mean of 27.7 degrees, p = 0.0001), flexion, and rotation. Total superior plication restricted external rotation and flexion. Localized plications of the glenohumeral joint capsule lead to predictable patterns of loss of glenohumeral mobility. If plication is planned, losses of movement can be anticipated. The findings of this study may assist surgeons in identifying the parts of the capsule that are contracted and that may need lengthening.The Journal of Bone and Joint Surgery 01/2003; 85-A(1):48-55. · 3.23 Impact Factor