Electrodiagnostic Predictors of Outcomes After In Situ Decompression of the Ulnar Nerve.

PURPOSE: Patients with severe ulnar neuropathy at the elbow frequently experience suboptimal surgical outcomes. Clinical symptoms alone may not accurately represent the severity of underlying nerve injury, calling for objective assessment tools, such as electrodiagnostic studies. The goal of our study was to determine whether specific electrodiagnostic parameters can be used to predict the outcomes after in situ decompression of the ulnar nerve. METHODS: This prospective study enrolled consecutive patients aged ≥18 years diagnosed with ulnar neuropathy at the elbow. Patients completed a baseline battery of motor, sensory, functional, and electrodiagnostic tests before undergoing in situ decompression of the ulnar nerve. They were reassessed at 6 weeks, 3 months, 6 months, and 12 months after surgery. Forty-two patients completed at least 2 follow-up assessments and were included in the study. RESULTS: When controlling for other electrodiagnostic measurements and demographic factors, none of the electrodiagnostic parameters were predictive of outcomes at 12 months after surgery. Patients with decreased compound muscle action potential amplitudes demonstrated slower trends of recovery in grip strength, pinch strength, and overall scores on the Michigan Hand Outcomes Questionnaire as well as its function, work, and activities of daily living subscales, Disabilities of the Arm, Shoulder, and Hand questionnaire, and the Carpal Tunnel Questionnaire. Decreased motor nerve conduction velocity was predictive of slower recovery of 2-point discrimination and pinch strength. CONCLUSIONS: Compound muscle action potential amplitude, but not other conventional electrodiagnostic parameters, was predictive of functional outcomes after in situ decompression of the ulnar nerve. This parameter should play a role in determining the timing and prognosis of treatment for ulnar neuropathy at the elbow. TYPE OF STUDY/LEVEL OF EVIDENCE: Prognostic II.

Severe myositis of the hip flexors after pre-operative chemoradiation therapy for locally advanced rectal cancer: case report.

BACKGROUND: The use of neoadjuvant radiation therapy and chemotherapy in the treatment of locally advanced rectal adenocarcinoma has been shown to reduce disease recurrence when combined with surgery and adjuvant chemotherapy. We report a case of a patient who developed a debilitating bilateral myopathy of the hip flexors after successful treatment for rectal cancer. To the best of our knowledge, this is the first such complication from radiation therapy reported in a patient with colorectal cancer. The disproportionate severity of our patient's myopathy relative to the dose of radiation used also makes this case unique among reports of neuromuscular complications from radiation therapy. CASE PRESENTATION: The patient is a 65-year-old male with node negative, high-grade adenocarcinoma of the rectum penetrating through the distal rectal wall. He underwent neoadjuvant concurrent pelvic radiation therapy and capecitabine-based chemotherapy, followed by abdominoperineal resection and post-operative FOLFOX chemotherapy. Five months post-completion of pelvic radiotherapy and 2 months after the completion of adjuvant chemotherapy, he presented with bilateral weakness of the iliopsoas muscles and severe pain radiating to the groin. The patient improved with 40 mg/d of prednisone, which was gradually tapered to 2 mg/d over 6 months, with substantial recovery of muscle strength and elimination of pain. CONCLUSIONS: The timing, presentation and response of our patient's symptoms to corticosteroids are most consistent with a radiation recall reaction. Radiation recall is a phenomenon whereby previously irradiated tissue becomes vulnerable to toxicity by subsequent systemic therapy and is rarely associated with myopathies. Radiation recall should be considered a potential complication of neoadjuvant radiation therapy for rectal cancer, and for ongoing research into the optimization of treatment for these patients. Severe myopathies caused by radiation recall may be fully reversible with corticosteroid treatment.

A Geospatial Analysis of Hand Trauma Care: A Statewide Cross-Sectional Study.

BACKGROUND: Traumatic hand injuries often present with high acuity, but little is known about the influence of geospatial and socioeconomic factors on the timely delivery of care. METHODS: This cross-sectional study used the Michigan Trauma Quality Improvement Program database, a state-wide registry with 35 level I or II trauma centers. Adult patients sustained hand trauma requiring urgent operative treatment between 2016 and 2021. Zip codes of injury location were linked with the corresponding percentile score on the Area Deprivation Index (ADI), a comprehensive measure of neighborhood disadvantage. Multiple regression analyses were used to determine associations of patient, injury and geospatial characteristics with the odds of sustaining acute hand trauma and time to operative treatment. RESULTS: Among 1,826 patients, the odds of sustaining acute hand trauma based on the ADI followed a bimodal distribution. Female sex, smoking, obesity, work-related injury and residence in a minor city were associated with increased odds, while younger age, comorbidities, and rural residence were associated with decreased odds. For 388 patients who underwent surgery within 48 hours, time to treatment was significantly increased in the highest ADI quintile, for patients who underwent fracture fixation, and for those with severe global injury severity. Multi-system injuries, moderate global injury severity and direct admission to an orthopaedic service were associated with shorter times to treatment. CONCLUSIONS: Patients in areas with greater neighborhood disadvantage may experience delayed operative care after acute hand trauma. This study highlights the importance of considering underserved populations and geospatial factors when determining the allocation of hand surgery resources. LEVEL OF EVIDENCE: Prognostic Level III.

Compound Muscle Action Potential Amplitude as a Predictor of Functional and Patient-Reported Outcomes in Ulnar Neuropathy at the Elbow.

BACKGROUND: Ulnar neuropathy at the elbow (UNE) is a debilitating upper extremity condition that often leaves patients with residual symptoms even after surgical treatment. The role of electrodiagnostic studies in guiding the treatment of UNE is not well established, and conventional electrodiagnostic parameters may not reflect the severity of disease. Compound muscle action potential (CMAP) amplitude is a parameter that corresponds with axonal injury and motor symptoms and may more accurately predict the severity of neurologic injury. METHODS: This prospective multicenter study recruited 78 patients in the Surgery of the Ulnar Nerve project. Patients underwent electrodiagnostic testing and clinical assessment of motor and sensory function, and completed patient-reported outcome questionnaires, including the Michigan Hand Outcome Questionnaire; the Disabilities of the Arm, Shoulder and Hand questionnaire; and the Carpal Tunnel Questionnaire (CTQ). Correlations were measured among each of the electrodiagnostic parameters and outcomes and predictive models for each outcome were subsequently developed. RESULTS: Of all the electrodiagnostic parameters measured, only CMAP amplitude was predictive of scores on the Michigan Hand Outcome Questionnaire; Disabilities of the Arm, Shoulder and Hand questionnaire; CTQ function scale, and motor impairment in grip and pinch strength. None of the parameters were predictive of scores on the CTQ symptom scale or sensory impairments as measured with two-point discrimination or Semmes-Weinstein monofilament testing. CONCLUSIONS: CMAP amplitude, but not other conventional electrodiagnostic parameters, is predictive of functional outcomes in UNE. This electrodiagnostic measurement can alert the clinician to severe cases of UNE and inform surgical decision-making. CLINICAL QUESTION/LEVEL OF EVIDENCE: Risk, III.

Vascularized Bone Flaps for the Treatment of Kienböck Disease.

Of the many treatments for Kienböck disease, only lunate revascularization procedures provide a direct mechanism for reversing the process of osteonecrosis. Owing to the redundant blood supply of the distal radius and carpus, pedicled flaps are versatile solutions for patients with bone loss but intact cartilage. With the advent of free vascularized flaps, the indications for lunate revascularization procedures are expanding. These flaps can be used when the articular cartilage has been compromised and are suitable options to restore native anatomy in patients previously thought to have unreconstructible disease.

Differential effects of clozapine, metoclopramide, haloperidol and risperidone on acquisition and performance of operant responding in rats.

RATIONALE: Prior research has not systematically investigated the effects of systemic antipsychotic drugs on operant response acquisition, specifically their behavioural microstructure, reinforcement blunting and relative potency in acquisition compared to performance once operant responding has stabilized. OBJECTIVES: This study aims to systematically investigate the effects of systemically administered clozapine, metoclopramide, haloperidol and risperidone during free operant response acquisition and performance. METHODS: Following magazine training, food-restricted male Wistar rats lever pressed for food reward in 15 min daily operant conditioning sessions. RESULTS: All drugs suppressed operant response acquisition and performance. Risperidone and metoclopramide, but not clozapine or haloperidol, suppressed operant responding more potently during acquisition than performance. The dopamine D2-like receptor antagonists haloperidol and metoclopramide that affect the ventral and dorsal striatum blunted reinforcement and decreased inactive lever presses in acquisition. In contrast, the atypical antipsychotics clozapine and risperidone that affect the ventral striatum and prefrontal cortex failed to decrease inactive lever presses during acquisition, suggesting a possible decision-making deficit. Haloperidol decreased active lever pressing over performance days. The drugs did not appear to affect rats' sensitivity to active lever press outcome, even though they suppressed active lever pressing. CONCLUSIONS: Results suggest that reinforcement impact during operant acquisition is dependent on dopamine D2 receptors while drugs affecting, among other areas, the prefrontal cortex produce a deficit in ability to suppress inactive lever press responses.

Regional differences in the action of antipsychotic drugs: implications for cognitive effects in schizophrenic patients.

Antipsychotic drugs (APDs) have been classified as typical or atypical based on their liability to produce extrapyramidal side effects: atypical APDs are less likely to produce extrapyamidal side effects at therapeutic doses. Evidence from immediate early gene immunohistochemical, electrophysiological, microdialysis, imaging, and behavioral studies suggests that typical APDs preferentially affect the nucleus accumbens (NAc) and the dorsal striatum while atypical APDs preferentially affect the NAc and medial prefrontal cortex (PFC). We review some of this evidence and then discuss studies that have employed cognitive tasks shown previously to depend on dorsal striatal or medial PFC function in schizophrenic patients treated with typical or atypical APDs. Results revealed that patients treated with typical APDs displayed deficits in cognitive tasks that depended on the dorsal striatum but not in tasks that depended on the medial PFC and that those treated with atypical APDs displayed deficits in cognitive tasks that depended on the medial PFC but not in cognitive tasks that depended on the dorsal striatum. These findings suggest that some of the cognitive deficits seen in schizophrenic patients may be related to the medications that are used to treat them.