Comparison of Peripheral Nerve Axonal Area Differences in Central and Peripheral Zones of Injured and Repaired Nerves.

BACKGROUND: Histological analysis remains a cornerstone approach for the investigation of peripheral nerve regeneration. This study investigates a newly recognized histological difference between peripheral and central zones within the regenerating nerve trunks. PURPOSE: The purpose of the study was to determine if the nerve axonal area (NXA) in regenerating peripheral nerves differs within central and peripheral areas, when viewed in cross-section. METHODS: A total of 14 rats were divided into two groups, and subjected to different injuries to the right sciatic nerve. Group 1: Transection injury with immediate repair. Group 2: Crush injury without any treatment. The left sciatic nerve was left uninjured and served as a control in each rat. Following 4 weeks of recovery, nerve trunk cross-sections were prepared. Computerized techniques were then employed to divide nerve sections into central and peripheral zones and calculate corresponding NXA values for subsequent statistical analysis. RESULTS: NXA of injured nerves was greater within peripheral as compared with the central zones, independent of injury type (p < 0.05). No statistically significant difference existed within the control groups or between the injury methods with regards to NXA regeneration extent. CONCLUSION: NXA in regenerating peripheral nerves was greater in the peripheral zones than within the central zones.

Anterior Scalene Muscle Block Response Predicts Outcomes Following Thoracic Outlet Decompression.

BACKGROUND: There is no definitive objective measure for diagnosis of thoracic outlet syndrome (TOS), and functional capacity testing on standardized rehabilitation exercises before and after an anterior scalene muscle block (ASMB) has the potential to serve as a predictor of response to surgery and to improve diagnostic accuracy in these cases. METHODS: Patients evaluated for TOS underwent ASMB as a diagnostic test and were retrospectively reviewed. Functional capacity scores were recorded for patients performing repetitive motion exercises immediately before ASMB, 15 minutes after ASMB, and at a minimum of 6 weeks after thoracic outlet decompression (TOD). The primary outcome of interest was correlation between the pre- to post-ASMB difference and the pre-ASMB to postoperative difference with respect to 3 functional work capacity scores. RESULTS: The average change in time-to-fatigue and work product between pre- and post-ASMB of all exercises was an increase of 39.5% and 53.8%, respectively. The greatest pre-ASMB to post-TOD difference was seen for the Extremity Abduction Stress Test with an average improvement of 109.7% and 150.4% for time-to-fatigue and work product, respectively. The degree of percent improvement post-ASMB correlated positively with the degree of percent improvement post-TOD for all exercises with respect to work product and time-to-fatigue. CONCLUSIONS: Patient response to ASMB as measured by functional capacity on rehabilitation exercises predicted objective functional outcomes following TOD. Post-ASMB outcomes correlated with post-TOD outcomes. The ASMB can be used to assist in diagnosing TOS and provide a surrogate for expectation in patients considering undergoing neurogenic TOD.

Ischemic Pain.

This article discusses the pathophysiology, presentation, cause, and treatment of ischemic pain in the surgical patient. Causes of ischemic pain vary but all fundamentally cause local acidosis in the peripheral tissues, which causes signals to be passed through ascending pain pathways to the thalamus and eventual cerebral cortex where it is interpreted as ischemic pain. Ischemic pain is classically associated with an insidious onset but can present in the acute or chronic setting. Treatments are aimed at improving perfusion to the affected tissue. Surgical options include repairing damaged vessels, bypassing diseased vessels, performing thrombectomy, or embolectomy. Numerous conservative therapies exist.

Perioperative Pain Management in Hand and Upper Extremity Surgery.

Perioperative pain management in surgery of the hand and upper extremity relies on a multimodal approach involving systemic, local, and presurgical considerations. A pain management plan should be tailored to each patient. Management of pain of patients undergoing upper extremity surgery begins before surgical intervention and continues postoperatively. Patient education, setting expectations, psychological interventions, and addressing risk factors associated with postoperative pain are critical to successful pain management. Intraoperative anesthesia is accomplished via a variety of means. Cryotherapy, transcutaneous electrical nerve stimulation, acupuncture, massage, and localized heat are used in concert with pharmacologic therapies postoperatively to continue pain management.