Clinical and electromyographic features of radiation-induced lower cranial neuropathy

Late radiation-associated dysphagia following treatment for head and neck cancer: a scoping review

PURPOSE

To provide an overview of existing literature reporting swallowing outcomes beyond two years post- head and neck cancer treatment. Objectives were to establish prevalence of late radiation-associated dysphagia (-RAD); identify risk factors of developing late-RAD and synthesise the dysphagia findings reported.

METHODS

The PRISMA-ScR checklist for conducting scoping reviews was adopted. Searches of PubMed, EMBASE, Scopus, CINAHL, Web of Science, OpenGrey, Google Scholar and Google Advanced were completed by December 2022. Eligibility criteria included studies written in English from 1996 reporting swallowing outcomes from 2 years or more post-treatment. Data was extracted from included studies, tabulated, synthesised and reported as categories.

RESULTS

Screening 7671 studies resulted in 39 studies included in the review. There was wide variation in dysphagia outcome measures used and timing of collection across studies. Prevalence could not be established. All studies reported a degree of impairment in at least one measure in a proportion of patients. Numerous risk factors were identified (including tumour site, and T-classification, age, radiotherapy dose), but there were conflicting findings and meaningful synthesis was challenging. Characteristics of late-RAD included high aspiration rates; reduced efficiency of swallowing and lower cranial neuropathy.

CONCLUSION

Significant gaps exist in the evidence base regarding late-RAD such as who is affected, why and what the trajectory of decline will be. Swallowing safety is often compromised. A consensus on the definition of late-RAD is needed along with increased uniformity in collection of outcome measures, in order to improve understanding and guide future research and service delivery models.

Chronic shoulder pain due to spinal accessory nerve palsies present opportunities for improved care integration

Aim: Chronic shoulder pain due to iatrogenic spinal accessory nerve (SAN) injury continues to be under-recognized, resulting in delayed time-to-diagnosis and poorer outcomes. Solutions are needed to improve the management of this condition, which can be challenging as care needs to be coordinated across pain management, neurophysiology, rehabilitation and reconstructive surgery.Cases: We present a series of six patients with shoulder pain refractory to conservative pain treatments to highlight how SAN injuries continued to be missed and treatment delayed, even at advanced care centers. The time to diagnosis of SAN palsy took an average of 21 months and treatment was inconsistent for all patients.Discussion: None of the six cases had initial suspicion of SAN palsy and only one patient received targeted SAN injury care. SAN treatment should be started as early as possible so that patients can be referred for prompt surgical evaluation if they fail conservative management. Integrated care pathways may be a solution for formalizing multidisciplinary team involvement and improving SAN injury outcomes.Conclusion: Systemic processes, such as integrated care pathways, are needed to optimize early recognition and targeted treatment of SAN injury and may be beneficial for other underdiagnosed and undertreated neuropathic pain conditions.

Electromyography findings in radiation-induced unilateral tongue immobility

BACKGROUND

We used electromyography to characterize hypoglossal nerve function among radiation-treated head and neck cancer survivors with later onset unilateral tongue immobility.

METHODS

Patients with unilateral tongue immobility without evidence of recurrent cancer were seen at a tertiary academic institution between February and September 2021. All patients were at least 2 years post-treatment with radiation therapy for head and neck squamous cell carcinoma. Participants were under annual surveillance and displayed no evidence of operative injury to the hypoglossal nerve.

RESULTS

The median symptom-free interval for the 10 patients included in this study was 13.2 years (range 2-25 years). Myokymia alone was present in 3 of 10 patients, fibrillation potentials alone were present in 3 of 10 patients, and 1 subject displayed both fibrillation and myokymia. Three out of 10 patients had normal hypoglossal nerve function.

DISCUSSION

These findings highlight how disparate mechanisms may underlie similar clinical presentations of radiation-induced neuromuscular dysfunction.

EMG-Phänomene peripherer motorisch axonaler Übererregbarkeit

Bei der Nadel-Elektromyographie (EMG) besitzen Phänomene der vermehrten Erregbarkeit von Muskelfasern und von motorischen Axonen Bedeutung für die Diagnostik neuromuskulärer Erkrankungen. Zur motorisch axonalen Übererregbarkeit gehören spontane Phänomene wie Faszikulationen, spontane kontinuierliche Einzelentladungen der motorischen Einheit (SKEME), Myokymien, neuromyotone Entladungsserien und Krampi. Ferner gehören dazu reizinduzierte Phänomene wie manche A-Wellen, reizinduzierte komplex repetitive Entladungen oder tetanischen Spasmen bei Elektrolytstörungen. In der vorliegenden Übersicht wird der Kenntnisstand zu den verschiedenen Phänomenen motorisch axonaler Übererregbarkeit referiert. Ein Schwerpunkt liegt dabei auf den SKEME als neuem Mitglied der Gruppe spontaner Potenziale aus dem motorischen Axon.

Delayed lower cranial neuropathy after oropharyngeal intensity-modulated radiotherapy: A cohort analysis and literature review

BACKGROUND

The purpose of this study was to examine swallowing-related lower cranial nerve palsy (LCNP) in oropharyngeal cancer (OPC) survivors after intensity-modulated radiotherapy (IMRT).

METHODS

Patients treated with definitive IMRT (66-72 Gy) were pooled from institutional trial databases. Prospective analyses on parent trials included videofluoroscopy, clinical LCNP examination, and questionnaires pre-IMRT, 6 months post-IMRT, 12 months post-IMRT, and 24 months post-IMRT. Time-to-event and incidence of LCNP was estimated with competing risk methods. Literature review (1977-2015) summarized published LCNP outcomes.

RESULTS

Three of 59 oropharyngeal cancer survivors with a minimum 2-year follow-up developed hypoglossal palsy ipsilateral to the index tumor (median latency 6.7 years; range 4.6-7.6 years). At a median of 5.7 years, cumulative incidence of LCNP was 5%. LCNP preceded progressive dysphagia in all cases. Published studies found median incidence of radiation-associated LCNP was 10.5% after NPC, but no OPC cancer-specific estimate.

CONCLUSION

Although uncommon, the potential for late LCNP preceding swallowing deterioration highlights the importance of long-term functional surveillance in OPC survivorship.

Tongue myokymia presenting twelve years after radiation therapy

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Radiation therapy may damage the hypoglossal nerve causing axonal hyperexcitability and myokymia of the tongue.

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Delayed effects of radiation therapy might be seen decades later.

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Detecting myokymic discharges is significative in differential diagnosis.

Objective

This case is a patient with tongue myokymia following radiation therapy 12 years earlier, documented using video and EMG.

Case report

A 68-year-old woman with a history of nasopharyngeal carcinoma presented with subacute onset of difficulty in speaking and involuntary movements of her tongue approximately 12 years after radiation therapy to head and neck. Electromyography displayed myokymic discharges. There was no evidence of recurrent malignancy.

Significance

Delayed effects of radiation therapy might be seen decades later. Myokymic discharges may reveal radiation-induced neuropathy.

Beyond mean pharyngeal constrictor dose for beam path toxicity in non-target swallowing muscles: Dose-volume correlates of chronic radiation-associated dysphagia (RAD) after oropharyngeal intensity modulated radiotherapy

PURPOSE/OBJECTIVE(S)

We sought to identify swallowing muscle dose-response thresholds associated with chronic radiation-associated dysphagia (RAD) after IMRT for oropharyngeal cancer.

MATERIALS/METHODS

T1-4 N0-3 M0 oropharyngeal cancer patients who received definitive IMRT and systemic therapy were examined. Chronic RAD was coded as any of the following ⩾12months post-IMRT: videofluoroscopy/endoscopy detected aspiration or stricture, gastrostomy tube and/or aspiration pneumonia. DICOM-RT plan data were autosegmented using a custom region-of-interest (ROI) library and included inferior, middle and superior constrictors (IPC, MPC, and SPC), medial and lateral pterygoids (MPM, LPM), anterior and posterior digastrics (ADM, PDM), intrinsic tongue muscles (ITM), mylo/geniohyoid complex (MHM), genioglossus (GGM), masseter (MM), buccinator (BM), palatoglossus (PGM), and cricopharyngeus (CPM), with ROI dose-volume histograms (DVHs) calculated. Recursive partitioning analysis (RPA) was used to identify dose-volume effects associated with chronic-RAD, for use in a multivariate (MV) model.

RESULTS

Of 300 patients, 34 (11%) had chronic-RAD. RPA showed DVH-derived MHM V69 (i.e. the volume receiving⩾69Gy), GGM V35, ADM V60, MPC V49, and SPC V70 were associated with chronic-RAD. A model including age in addition to MHM V69 as continuous variables was optimal among tested MV models (AUC 0.835).

CONCLUSION

In addition to SPCs, dose to MHM should be monitored and constrained, especially in older patients (>62-years), when feasible.

Late radiation-associated dysphagia with lower cranial neuropathy in long-term oropharyngeal cancer survivors: video case reports

BACKGROUND

Lower cranial neuropathies are a late effect of radiotherapy (RT), typically reported in nasopharyngeal cancer survivors. Limited data examine these neuropathies after oropharyngeal cancer, particularly as it relates to late radiation-associated dysphagia (late-RAD).

METHODS

Two cases were examined over 4 to 6 years. Late-RAD was assessed per MBS impairment profile (MBSImP™©), Penetration-Aspiration Scale (PAS), Performance Status Scale for Head and Neck cancer (PSS-HN), and MD Anderson Dysphagia Inventory (MDADI). Neuropathies were examined via clinical examination and laryngeal videostroboscopy, and compared with trajectories of late-RAD.

RESULTS

Media-enriched case reports describe the course of late-RAD and neuropathies in 2 cases after definitive RT ± epidermal growth factor receptor-inhibitor for oropharyngeal cancer. Late-RAD was characterized by severe physiologic impairments per MBSImP™© and decreased swallowing-related quality of life (QOL) per MDADI. Trajectories of late-RAD paralleled the progression or stability of neuropathies.

CONCLUSION

Late-RAD with lower cranial neuropathies resulted in profound and persistent functional impairment. Rarely reported, late radiation-associated lower cranial neuropathies may be a major contributor to new-onset or progressive dysphagia in long-term oropharyngeal cancer survivors.