Mechanomyography as a Surgical Adjunct for Treatment of Chronic Entrapment Neuropathy: A Case Series.

BACKGROUND: Chronic entrapment neuropathy results in a clinical syndrome ranging from mild pain to debilitating atrophy. There remains a lack of objective metrics that quantify nerve dysfunction and guide surgical decision-making. Mechanomyography (MMG) reflects mechanical motor activity after stimulation of neuromuscular tissue and may indicate underlying nerve dysfunction. OBJECTIVE: To evaluate the role of MMG as a surgical adjunct in treating chronic entrapment neuropathies. METHODS: Patients 18 years or older with cubital tunnel syndrome (n = 8) and common peroneal neuropathy (n = 15) were enrolled. Surgical decompression of entrapped nerves was performed with intraoperative MMG of the hypothenar and tibialis anterior muscles. MMG stimulus thresholds (MMG-st) were correlated with compound muscle action potential (CMAP), motor nerve conduction velocity, baseline functional status, and clinical outcomes. RESULTS: After nerve decompression, MMG-st significantly reduced, the mean reduction of 0.5 mA (95% CI: 0.3-0.7, P < .001). On bivariate analysis, MMG-st exhibited significant negative correlation with common peroneal nerve CMAP ( P < .05), but no association with ulnar nerve CMAP and motor nerve conduction velocity. On preoperative electrodiagnosis, 60% of nerves had axonal loss and 40% had conduction block. The MMG-st was higher in the nerves with axonal loss as compared with the nerves with conduction block. MMG-st was negatively correlated with preoperative hand strength (grip/pinch) and foot-dorsiflexion/toe-extension strength ( P < .05). At the final visit, MMG-st significantly correlated with pain, PROMIS-10 physical function, and Oswestry Disability Index ( P < .05). CONCLUSION: MMG-st may serve as a surgical adjunct indicating axonal integrity in chronic entrapment neuropathies which may aid in clinical decision-making and prognostication of functional outcomes.

Tourniquet Use Does Not Affect Functional Outcomes or Pain After Total Knee Arthroplasty: A Prospective, Double-Blinded, Randomized Controlled Trial.

BACKGROUND: The use of a tourniquet during total knee arthroplasty (TKA) is controversial. Pain and return to function are believed, by some, to be influenced by the use of a tourniquet. The hypothesis of this study was that use of a tourniquet would delay postoperative functional recovery and increase pain as compared with no tourniquet use. METHODS: Two hundred patients were recruited for this prospective, double-blinded, randomized controlled trial. Patients were randomized to undergo TKA either with a tourniquet (100 patients) or without one (100 patients) and blinded to group allocation. Primary outcome measures were functional assessment testing using the Timed Up & Go (TUG) test and visual analog scale (VAS) pain scores. Secondary outcome measures included the stair-climb test, blood loss, surgical field visualization, and range of motion. Outcome measures were completed preoperatively, in the hospital, and postoperatively at a first and a second follow-up. The minimal detectable change, Student t test, Fisher exact test, and nonasymptotic chi-square analysis with an alpha of p < 0.05 were used to determine significance. RESULTS: The no-tourniquet group had more calculated blood loss (1,148.02 mL compared with 966.64 mL; p < 0.001) and more difficulty with surgical field visualization (p < 0.0001). The tourniquet group had greater knee extension at the first follow-up (-7° compared with -9°; p = 0.044). CONCLUSIONS: Tourniquet use during TKA significantly decreases blood loss and does not adversely affect early postoperative outcomes. Tourniquet use during routine TKA is safe and effective, and concerns about deleterious effects on function and pain may not be justified. LEVEL OF EVIDENCE: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.