Oishi, Tatsuya

Summary: Facial synkinesis manifests as involuntary muscle movements alongside volitional facial actions and is typically managed with a combination of neuromuscular retraining, botulinum toxin injections, and in some cases, selective neurectomy. Some patients with synkinesis describe persistent neck tightness or pain at the level of the mandibular angle and horizontally towards the midline, similar to the anatomic course of the posterior belly of digastric (PBD) and stylohyoid muscles. There are limited studies exploring the involvement of the PBD and stylohyoid muscles in facial synkinesis and the use of chemodenervation as treatment. Herein, we present 2 patients with facial synkinesis and ipsilateral neck tightness and pain who underwent novel surgical treatment in the form of the standard selective neurectomy procedure along with a myectomy of the PBD and stylohyoid muscles. Following completion of the standard steps of selective neurectomy, the PBD and stylohyoid muscles were carefully dissected and separated from the surrounding structures. Both muscles were divided using bipolar electrocautery. Both patients reported improvement of neck pain and tightness immediately after the intervention and at the 6.5-month follow-up visit. These preliminary results show promise in aiding a subset of patients with synkinesis-related neck pain and tightness.

Motor-evoked potential (MEP) monitoring is an electrophysiologic technique useful for testing peripheral motor nerve integrity during cryoablation cases with risk of nerve injury. Previously, neuromonitoring within the magnetic resonance imaging (MRI) suite for cryoablation has not been performed as magnetic needles are used which could cause magnetic field interactions with neuromonitoring leads. We present the first report of a patient who underwent MEP monitoring during MRI-guided cryoablation of a vascular malformation adjacent to the brachial plexus. We demonstrate that MEPs may be safely and accurately performed by interleaving MRI and MEPs during treatment, reducing the risk of postprocedural complications.

OBJECTIVE The objective of this study was to describe the quantitative features of intraoperative electromyographic recordings obtained from cranial nerve III, IV, and VI neuromonitoring using 25-mm intraorbital electrodes, in the larger context of demonstrating the practicality of this technique during neurosurgical cases. METHODS A 25-mm-long shaft-insulated intraorbital needle electrode is routinely used at the authors’ institution for extraocular muscle (EOM) electromyographic monitoring of the inferior rectus, superior oblique, and/or lateral rectus muscles when their function is at risk. Cases monitored between January 1, 2021, and December 31, 2022, were reviewed for patient demographics, tumor location and pathology, EOMs monitored, pre- and postoperative examination, and complications from electrode placement. Compound muscle action potentials on triggered electromyography, as well as neurotonic discharges on free-run electromyography, were described quantitatively. RESULTS There were 141 cases in 139 patients reviewed during the 24-month time span, with 278 EOMs monitored (inferior rectus/superior oblique/lateral rectus muscles 68/68/142). Triggered electromyography yielded biphasic or triphasic compound muscle action potentials from EOMs with a mean onset latency of 1.51 msec (range 0.94–3.22 msec), mean maximal peak-to-trough amplitude of 1073.93 μV (range 76.75–7796.29 μV), and high specificity for the channel in nearly all cases. Neurotonic discharges were recorded in 30 of the 278 EOMs (with all 3 muscles represented) and associated with a greater incidence of new or worsened ophthalmoparesis (OR 4.62, 95% CI 1.3–16.4). There were 2 cases of small periorbital ecchymosis attributed to needle placement; additionally, 1 case of needle-related intraorbital hematoma occurred after the review period. CONCLUSIONS The 25-mm shaft-insulated intraorbital electrode facilitates robust and consistent electromyographic recordings of EOMs that are advantageous over existing techniques. Combined with the relative ease of needle placement and low rate of complications, the technique is practical for neuromonitoring during craniotomies.

Abstract Objectives: Periodic paralysis is a rare genetic condition characterized by episodes of neuromuscular weakness, often provoked by electrolyte abnormalities, physiologic stress, physical exertion, and diet. In addition to mutations in genes coding for skeletal muscle ion channels, in 2019, Gustavasson et al discovered that the MCM3AP gene could be responsible for periodic paralysis. In this study, we present 2 individuals with clinical episodes of periodic paralysis who have variants in the MCM3AP gene. Methods: Two unrelated probands were independently evaluated with clinical, genetic, and electrodiagnostic testing. Results: Proband 1 is a 46-year-old man who presented with decades of ongoing episodic weakness and fatigue, clinically diagnosed with periodic paralysis and supported by electrodiagnostic studies. Proband 2 is a 34-year-old woman with a history of episodic paralysis since childhood. Genetic testing in both individuals revealed potentially pathogenic variants in the MCM3AP gene. Conclusions: Periodic paralysis is a condition that significantly affects the lives of those diagnosed. The results illustrate that MCM3AP gene variants can been associated with a clinical and electrodiagnostic presentation of periodic paralysis. Additional future research should focus on clarifying any relationship between these genetic variants and the disease, as well as other possible genetic causes.

BACKGROUND AND IMPORTANCE: Snapping of the triceps muscle occurs when a portion of the medial head dislocates over the medial epicondyle with elbow flexion. Resection or redirection of a portion of the triceps muscle is the main surgical treatment. The extent of triceps resection/redirection is difficult to evaluate. A novel intraoperative technique, stimulating the musculocutaneous nerve, to simulate active elbow flexion is proposed to help ensure that the snapping triceps has been adequately treated. CLINICAL PRESENTATION: A patient presented with a several year history of bilateral elbow pain, snapping, and ulnar nerve (UN) paresthesias. Previous staged bilateral subcutaneous UN transpositions were performed at another institution for documented UN dislocation and neuritis. Postoperatively symptoms of painful snapping persisted. Bilateral snapping triceps was diagnosed. The left elbow was reoperated. Intraoperative electrical stimulation of the musculocutaneous nerve was performed to reproduce the snapping triceps. Activation of the biceps/brachialis muscles produced powerful elbow flexion, allowed direct visualization of the forceful snapping triceps, and helped assess the adequacy of muscle resection/redirection. CONCLUSION: Intraoperative biceps/brachialis stimulation can potentially help determine how much triceps muscle should be resected/redirected to treat patients with snapping triceps.

AbstractIntroductionMyokymic discharges are classically associated with nerve injury from prior radiation but may occur in other neuromuscular disorders. Using quantitative analysis we aimed to identify the spectrum of conditions in which myokymic discharges are present and determine if there are electrophysiological features that distinguish postradiation from nonradiation causes of myokymia.MethodsWe reviewed the clinical history of all patients examined in our electromyography labs with myokymic discharges recorded from June 2017 to February 2020. Quantitative analysis of each myokymic discharge was performed using a custom MATLAB script, assessing features such as burst frequency, spikes per burst, and burst regularity.ResultsEighty‐eight distinct myokymic discharges (70 patients) were analyzed: 51 postradiation recordings from 35 patients and 37 recordings from 35 nonradiation patients. The diagnostic spectrum of nonradiation cases was diverse, with common causes being median neuropathy (n = 8), cervical (n = 7), and lumbar (n = 5) radiculopathy, and motor neuron disease (n = 5). On quantitative analysis, postradiation myokymia had an increased burst‐to‐silence ratio (median, 0.29; nonradiation, 0.08) and greater peak number (median, 15; nonradiation, 7). Except for one patient with hereditary peripheral nerve hyperexcitability, all patients who had two or more muscles demonstrating myokymic discharges belonged to postradiation group.ConclusionsMyokymic discharges can be seen in diverse neuromuscular conditions; most common in our cohort was chronic median neuropathy. Postradiation myokymia appears to have distinguishing morphological features when quantitatively analyzed compared with nonradiation cases.

Abstract Our study aims to quantitate neuromuscular morbidity from radiotherapy in Hodgkin lymphoma including: (i) frequency and (ii) time of onsets for neurological localizations; (iii) degree of disabilities and (iv) number of clinical visits compared to cardiopulmonary Hodgkin lymphoma-radiation complications. Medical records from Mayo Health systems were retrieved; identifying neuromuscular radiation treated Hodgkin lymphoma-complications from 1 January 1994 to 31 December 2016. Of an estimated 4100 post-radiotherapy Hodgkin lymphoma patients, 4.6% (189) were identified with complications. Mean latency to physician visit for symptoms was 23.7 years (range: 1–50). Most commonly identified complications included: head drop 10% (19) with or without myopathy, myopathy 39% (73), plexopathy 29% (54), myelopathy 27% (51) and polyradiculopathy 13% (24). Other findings included benign and malignant nerve sheath tumours 5% (9), phrenic and long thoracic mononeuropathies 7% (14) and compressive spinal meningioma 2% (4). Patients frequently had multiple coexisting complications (single = 76% [144], double = 17% [33], triple = 4% [8], quadruple = 2% [4]). Cardiac 28% (53) and pulmonary 15% (29) complications were also seen in these patients. History of Hodgkin lymphoma was initially overlooked by neurologists (14.3%, 48/336 clinical notes). Hospital and outpatient visits for complications were frequent: neuromuscular 19% (77/411) versus cardiopulmonary 30% (125/411). Testing was largely exclusionary, except when imaging identified secondary malignancy. Modified Rankin score at diagnosis varied: 0–1 (55.8%), 2–3 (5.8%) and 4–5 (38.3%). Neuromuscular complications among post-radiation Hodgkin lymphoma are diverse, occurring in ∼1 of 20 having markedly delayed onsets often eluding diagnosis. Frequent care visits and major morbidity are common. Survivorship recommendations should recognize the diverse neurological complications.