Case Description: In our outpatient clinic, three middle-aged male patients with oral squamous-cell carcinoma presented with chronic shoulder-pain and limited range of motion following neck-dissection, radiation, and chemotherapy. The exact cause of their symptoms was uncertain, but they reported that the shoulder pain started after their last radiation treatment, ranging from 11 to 36 months prior to seeking medical help. Their pain exhibited neuropathic and myofascial characteristics, accompanied by numbness, tingling, and radiating sensations. The debilitating pain significantly affected their daily activities and prior treatments, including injections, were ineffective in relieving pain.To determine the location of the lesion, the patients consented to comprehensive physical and electrodiagnostic-examinations, including thorough needle electromyogram (EMG) testing which confirmed spinal accessory nerve palsy.
Discussion: Understanding shoulder joint anatomy and conducting thorough physical exams and EMG tests are crucial for diagnosis. Misdiagnosis highlights the importance of accurate testing. Rule-outs for other causes, like brachial plexopathy, were done. Accurate diagnosis is vital to avoid misinterpretation and tailor treatment. Treating CN XI injury and trapezius weakness is essential to address shoulder-dysfunction and prevent complications due to compromised scapular-stabilizers. Strengthening exercises, bracing, and therapy can help, along with potential options like hyperbaric oxygen therapy and surgical procedures.
Setting: outpatient clinic
Assessment/Results: Severe trapezius muscle-weakness and atrophy were observed in these patients, with significant weakness in shoulder shrug and abduction, along with noticeable lateral-winging during arm movements. EMG and NCS results confirmed neuropathic changes isolated to the trapezius muscle, with reduced motor-unit recruitment and fasciculations. No abnormalities were found in other muscles. These findings underscore the need for targeted interventions to restore trapezius function and alleviate limitations in daily life.
Conclusion: Our case-series suggests that shoulder pain in oral cancer patients warrants evaluation for CN XI palsy, leading to scapular instability and dysfunction. Pain specialists should consider electrodiagnostic studies to aid diagnosis and treatment.