Electromyographic predictors of abducens nerve palsy after endoscopic skull base surgery.

OBJECTIVE: Recovery of abducens nerve palsy (ANP) after endoscopic endonasal skull base surgery (ESBS) has been shown to be potentially predicted by postoperative ophthalmological examination. Triggered electromyography (t-EMG) and free-run electromyography (f-EMG) activity provide an intraoperative assessment of abducens nerve function, but associations with long-term ANP outcomes have not been explored. The objective of this study was to describe intraoperative abducens EMG characteristics and determine whether these electrophysiological profiles are associated with immediately postoperative and long-term ANP outcomes after ESBS. METHODS: The authors conducted a 5-year (2011-2016) retrospective case-control study of patients who underwent ESBS in whom the abducens nerve was stimulated (t-EMG). Electrophysiological metrics were compared between patients with a new postoperative ANP (cases) and those without ANP (controls). Pathologies included chordoma, pituitary adenoma, meningioma, cholesterol granuloma, and chondrosarcoma. Electrophysiological data included the presence of abnormal f-EMG activity, t-EMG stimulation voltage, stimulation threshold, evoked compound muscle action potential (CMAP) amplitude, onset latency, peak latency, and CMAP duration at various stages of the dissection. Controls were selected such that pathologies were similarly distributed between cases and controls. RESULTS: Fifty-six patients were included, 26 with new postoperative ANP and 30 controls without ANP. Abnormal f-EMG activity (28.0% vs 3.3%, p = 0.02) and lack of response to stimulation (27% vs 0%, p = 0.006) were more frequent in patients with immediately postoperative ANP than in controls. Patients with immediately postoperative ANP also had a lower median CMAP amplitude (35.0 vs 71.2 µV, p = 0.02) and longer onset latency (5.2 vs 2.8 msec, p = 0.04). Comparing patients with transient versus persistent ANP on follow-up, those with persistent ANP tended to have a lower CMAP amplitude (12.8 vs 57 µV, p = 0.07) and higher likelihood of not responding to stimulation at the end of the case (45.5% vs 7.1%, p = 0.06). Abnormal f-EMG was not associated with long-term ANP outcomes. CONCLUSIONS: The presence of f-EMG activity, lack of CMAP response to stimulation, decreased CMAP amplitude, and increased CMAP onset latency were associated with immediately postoperative ANP. Long-term ANP outcomes may be associated with t-EMG parameters, including whether the nerve is able to be stimulated once identified and CMAP amplitude. Future prospective studies may be designed to standardize abducens nerve electrophysiological monitoring protocols to further refine operative and prognostic utility.

Botulinum Toxin Injection for the Treatment of Third, Fourth, and Sixth Nerve Palsy: A Meta-Analysis.

The efficacy of botulinum toxin injection for the treatment of third, fourth, and sixth nerve palsy was evaluated. PubMed, Scopus, EMBASE, Web of Science, and Google Scholar databases were searched. Data about the duration of palsy (acute vs chronic), cause of the palsy, type of toxin used, mean dose, and other background characteristics were collected. Outcome variables were success rate (defined by alleviation of diplopia or reduction in eye deviation) and standardized mean difference of prism diopter and abduction deficit before and after injection. The Joanna Briggs Institute checklist was implemented for the risk of bias assessment. The analysis included 38 articles, comprising 643 patients. The overall treatment success rate in acute and chronic nerve palsy was 79% and 33%, respectively. The success rate was not significantly different between different subgroups of age, type of botulinum toxin, pre-injection prism diopter, etiology of the palsy, duration of follow-up, and mean dose of botulinum toxin injection. However, in both acute and chronic palsy, diabetes etiology was accompanied by the highest success rate. Overall symptomatic response to botulinum injection was 84% (95% CI: 67% to 96%), whereas functional response was observed in 64% (95% CI: 47% to 79%) of the patients. The odds ratio for the success rate of treatment of palsies with botulinum toxin versus expectant management was 2.67 (95% CI: 1.12 to 6.36) for acute palsy and 0.87 (95% CI: 0.17 to 4.42) for chronic palsy. Botulinum toxin can be used for the treatment of acute third, fourth, and sixth nerve palsy, especially in patients with acute palsy and more severe tropia. [J Pediatr Ophthalmol Strabismus. 2024;61(3):160-171.].

Cranial Nerve Disorders Associated With Immune Checkpoint Inhibitors.

OBJECTIVE: To describe the spectrum, treatment, and outcome of cranial nerve disorders associated with immune checkpoint inhibitor (Cn-ICI). METHODS: This nationwide retrospective cohort study on Cn-ICI (2015-2019) was conducted using the database of the French Refence Center. In addition, a systematic review of the literature (MEDLINE, Scopus, and Web of Science) for records published between 2010 and 2019 was performed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines using the search terms cranial nerve or neuropathy or palsy and immune checkpoint inhibitors. RESULTS: Among 67 cases with ICI-related neurologic toxicities diagnosed in our reference center, 9 patients with Cn-ICI were identified (7 men, 78%, median age 62 years [range 26-82 years]). Patients were receiving a combination of anti-cytotoxic T-lymphocyte antigen 4 and anti-programmed cell death 1 (PD-1)/PD-1 ligand (n = 5, 56%) or anti-PD-1 antibodies alone (n = 4, 44%). Cn-ICI involved optic (n = 3), vestibulocochlear (n = 3), abducens (n = 2), facial (n = 2), and oculomotor (n = 1) nerves. Two patients had involvement of 2 different cranial nerves. Treatment comprised corticosteroids (n = 8, 89%), ICI permanent discontinuation (n = 7, 78%), plasma exchange (n = 2, 22%), and IV immunoglobulin (n = 1, 11%). Median follow-up was 11 months (range 1-41 months). In 3 cases (33%), neurologic deficit persisted/worsened despite treatment: 2 optic and 1 vestibulocochlear. Among cases from the literature and the present series combined (n = 39), the most commonly affected cranial nerves were facial (n = 13, 33%), vestibulocochlear (n = 8, 21%), optic (n = 7, 18%), and abducens (n = 4, 10%). Trigeminal, oculomotor, and glossopharyngeal nerves were less frequently affected (total n = 7). CONCLUSION: Cranial nerve disorders can complicate treatment with ICIs. Approximately one-third of the patients had persisting deficits, most frequently involving hearing and vision loss.

Tonic pupil caused by adenoid cystic carcinoma versus postradiation changes to the ciliary ganglion.

A tonic pupil, without other features of an oculomotor neuropathy, is due to a lesion in the ciliary ganglion or short ciliary nerves. Here, we present a case of a tonic pupil in a woman with radiation-treated adenoid cystic carcinoma of the nasopharynx with perineural spread and skull base involvement. This a rare case of a tonic pupil caused by direct invasion of the ciliary ganglion or postradiation effects.

The Medial Pontine Mid-Tegmentum Syndrome.

Isolated pontine infarcts are common and are often associated with well-described syndromes that are classified based on their specific clinical presentation and arterial stroke territories. Here we present a case of acute combined diplopia and unilateral lower extremity sensory abnormality. Diffusion-weighted magnetic resonance imaging revealed a punctate area of acute ischemia in the right medial pontine mid-tegmentum. These findings suggest a unique pontine stroke syndrome characterized by acute ischemic injury at the intersection of the medial lemniscus and cranial nerve VI.

Wernekink commissure syndrome secondary to a rare 'V'-shaped pure midbrain infarction: a case report and review of the literature.

Purpose: Wernekink commissure syndrome is a typical but extremely rare mesencephalic syndrome, and generally presents with bilateral cerebellar dysfunction, diverse oculomotor disorders and occasionally delayed-onset palatal myoclonus or tremor. However, it has been reported infrequently.Methods: We report a case of a 55-year-old man who suffered an acute paramedian midbrain infarction presenting with bilateral cerebellar ataxia, bilateral anterior internuclear ophthalmoplegia and unilateral pseudoabducens palsy, which is confirmed as Wernekink commissure syndrome by magnetic resonance imaging (MRI). We summarized the clinical data of this entity and performed a literature review of 20 previous reports of patients with this syndrome.Results: In combination with previous reports, we found that the most common symptom was bilateral cerebellar ataxia (100%) and other frequent symptoms were oculomotor disorders (81%), delayed palatal myoclonus or tremor (33%) and consciousness dysfunction (33%). Lesions on brain MRI of all patients affected the area of caudal paramedian midbrain (CPM).Conclusion: Bilateral cerebellar ataxia and lesions involved in the area of CPM on MRI are the major features of Wernekink commissure syndrome and should be the necessary conditions of diagnostic criteria. The simultaneous occurrence of bilateral cerebellar ataxia and oculomotor disorders is significant for localization diagnosis. Consciousness dysfunction is also a relatively frequent symptom of this syndrome. Moreover, pseudoabducens palsy might be attributed to a midbrain lesion. Clinicians should be familiar with and early to recognize this unique syndrome to avoid misdiagnosis.

Vertical rectus muscle union combined with lateral rectus plication for complete abducens nerve palsy.

PURPOSE: The aim of this study was to report our postoperative results concerning the vertical rectus (VR) muscle union combined with lateral rectus (LR) plication for the treatment of large-angle esotropia (ET) in complete abducens nerve palsy. METHODS: Medical records from 36 patients who had undergone the VR union procedure for ET treatment due to sixth-nerve palsy between July 2014 and July 2018 at Beyoglu Eye Research and Training Hospital were reviewed. One week before surgery, all patients underwent a 4-IU botulinum toxin A (btx) injection into the ipsilateral medial rectus (MR). All patients then underwent a VR muscle union procedure. A non-absorbable suture was inserted through the lateral muscular margin of each VR muscle at approximately 1/5 the width from the edge at 10 mm distance from the VR insertion. Both sutures were then tied to each other above the LR. Plication of the LR muscle using a non-absorbable suture was performed in all cases. RESULTS: The study population consisted of 14 (38.9%) females and 22 (61.1%) males. The mean age was 36.31 ± 19.16 years. The mean preoperative deviation angle in primary gaze into distance was 47.77 ± 18.48 prism diopter (PD). The mean deviation angle 1 year after surgery was - 1.0 ± 6.62 PD. Abduction improved from - 4.27 ± 0.46 to - 1.88 ± 0.96. CONCLUSION: The VR muscle union in combination with LR plication appears to be an effective treatment procedure for complete abducens nerve palsy patients.

Using Botulinum Toxin A as an Adjunct in the Surgery of Large-Angle Sensory Exotropia and Abducens Nerve Palsy.

Regarding the review article by Escuder AG, Hunter DG, entitled "The Role of Botulinum Toxin in the Treatment of Strabismus" Seminars in Ophthalmology. 2019;34(4): 198-204, we cannot agree with you more with your point of view about the dosage preparation for botulinum toxin A (BTA) in the strabismus surgery. Moreover, we also included a case series that used BTA as an adjunct in the surgery for large-angle sensory exotropia and abducens nerve palsy.

Vertical rectus transposition procedures for lateral rectus palsy: A systematic review.

Multiple transposition procedures have been described for management of lateral rectus palsy. However, relative effect and indications of each procedure are unclear. This systematic review was planned to evaluate functional and anatomical outcomes of vertical rectus transposition (VRT) surgery in patients with lateral rectus palsy. We searched databases in English language, namely, MEDLINE, PubMed Central, EMBASE, Google Scholar, Scopus, and Index Copernicus without any date restrictions in electronic searches, using the search words 'vertical rectus transposition for lateral rectus palsy," "vertical rectus transposition for abducens palsy," "superior rectus transposition," "inferior rectus transposition," and "Hummelsheim procedure." References of the selected publications were also searched to find any relevant studies. We searched for studies that provided data on single VRT and double VRT surgeries for lateral rectus palsies. Three authors independently assessed the related studies gathered from electronic and manual searches. We found 27 studies which were relevant to the review question. As there were no randomized control trials (RCTs) available related to our study question, nonrandomized studies were used to arrive at summarization of outcomes of different transposition procedures. There is a need for prospective RCTs to investigate the different types of transposition procedures for lateral rectus palsy.

Clinical characteristics of tuberculous meningitis combined with cranial nerve palsy.

OBJECTIVE: To retrospectively analyze the data of 72 patients with tuberculous meningitis (TBM) combined with cranial nerve palsy, to explore the incidence, clinical features, CSF assay changes and outcome in patients with TBM. PATIENTS AND METHODS: A total of 72 patients were diagnosed as TBM with cranial nerve palsy. The gender, age, clinical manifestations, CSF examinations, cerebral magnetic resonance imaging (MRI) enhancement scan were collected. All these patients had completed at least 2 months of follow up after anti-tuberculous treatment. RESULTS: This study retrospectively evaluated 486 patients; include 254 (52.3%) men and 232 (47.7%) women. The mean age was 35.2 ±â€¯17.0 years. 72 patients (14.8%) were diagnosed as TBM with cranial nerve palsy. Among them, 38 cases (52.8%) had optic nerve palsy (the 2nd nerve), 41 cases (56.9%) had oculomotor nerve palsy (the 3rd nerve), 3 cases (4.2%) had abducens nerve palsy (the 6th nerve), and 10 cases (13.9%) had auditory nerve palsy (the 8th nerve). 16 patients (22.2%) had two groups of cranial nerve involvement (oculomotor nerve and optic nerve in 10 cases, optic nerve and auditory nerve in 5 cases, and optic nerve and abducens nerve in 1 case). Two patients (2.8%) had three groups of cranial nerve involvement (oculomotor nerve, optic nerve and abducens nerve). CSF MTB was detected by acid fast bacilli (no patient was positive), MTB DNA detection by multiplex polymerase chain reaction (PCR) (3 patients were positive) and MTB cultures (2 patients were positive). There was no significant difference of CSF cells and biochemistry investigations between the patients with or without cranial nerve palsy. Magnetic resonance imaging (MRI) enhancement scan were done in 66 (91.7%) patients after admission. It was abnormal in 57 (86.3%) patients. 15 cases (26.3%) had meningeral enhancement, 25 cases (43.9%) had tuberculoma, 11 cases (19.3%) had hydrocephalus and 6 cases (10.5%) with infarct. All patients were followed up after 2 months of anti-tuberculous treatment. 70 patients (97.2%, 70/72) with the cranial nerve palsy were fully recovered without obvious sequel. CONCLUSION: The complications of cranial nerve palsy in TBM patients are not uncommon, and the rate of misdiagnosis is high, which makes them vulnerable to emergencies such as disturbance of consciousness. Effective anti-tuberculous treatment can restore most cranial nerve palsy.

A Rare Case of Anterior Segment Ischemia Following Wright's Modification of the Hummelsheim Procedure for Total Lateral Rectus Muscle Palsy.

A 53-year-old woman presented with diplopia and deviation of the left eye for the past 3 years. She had non-resolving isolated left lateral rectus palsy. She underwent a medial rectus recession and Hummelsheim (Wright's modification) procedure in her left eye. Postoperatively, the anterior segment ischemia resolved with steroids. [J Pediatr Ophthalmol Strabismus. 2019;56:e53-e56.].