Erector spinae plane block in a patient with post-thoracotomy pain syndrome and intercostal neuralgia presenting with late-onset myoclonus: a case report

Post-thoracotomy pain syndrome (PTPS) is a complex post-surgical chronic pain condition of the chest wall involving neuropathic, nociceptive, and nociplastic components, with intercostal neuralgia contributing in some cases. Intercostal neuralgia may occasionally present with motor manifestations, although such presentations have been infrequently described in the literature. Management of chronic PTPS remains challenging, particularly in cases refractory to medical therapy. The erector spinae plane block (ESPB) has been described as a regional analgesia technique in acute and chronic thoracic pain; however, its role in PTPS associated with motor symptoms has not been well defined. We report the case of a 60-year-old male who presented with severe chronic neuropathic pain in the left hemithorax seven years after undergoing a left posterolateral thoracotomy for lung mass excision. The pain was accompanied by late-onset myoclonus localized to the intercostal nerve distribution. Physical examination revealed hyperalgesia and high-frequency muscle spasms along the left T2–T6 dermatomes, with pain intensity rated as 8–9/10 on the Numeric Rating Scale (NRS; 0 = no pain, 10 = worst imaginable pain). Imaging studies showed expected postsurgical changes of the chest wall, without evidence of additional structural pathology contributing to the patient’s symptoms. Differential diagnoses, including herpes zoster infection and thoracotomy-related long thoracic and thoracodorsal nerve injuries, were considered less likely based on the clinical findings. With a preliminary diagnosis of PTPS and intercostal neuralgia, ultrasound-guided ESPB was performed at the T4 level using bupivacaine, lidocaine, and dexamethasone. Significant reduction in pain scores (NRS 1–2/10) and muscle spasm frequency was observed within 15 min. Due to recurrence of symptoms after 24 h, a second ESPB using bupivacaine and betamethasone was performed, followed by near-complete resolution of pain (NRS 0–1/10) and disappearance of muscle spasms. No complications were observed. The patient was discharged with oral neuropathic pain medication and referred for outpatient pain management follow-up. Telephone follow-up demonstrated significant symptom improvement for approximately three weeks. This case describes the use of ultrasound-guided ESPB in a patient with PTPS and intercostal neuralgia accompanied by late-onset myoclonic symptoms. ESPB was followed by rapid improvement in pain and reduction in involuntary muscle spasms. These observations may support further discussion of the possible role of ESPB in selected patients with PTPS, intercostal neuralgia, and associated motor manifestations.