We report a very rare case of referred pain caused by greater occipital nerve (GON) entrapment, inducing spontaneous pain in the whole body as well as in the trigeminal nerve region of the face and head. It has already been reported that entrapment of the GON can induce referred pain in the ipsilateral limb as well as the ipsilateral hemiface. A 42-year-old female patient presented with chronic pain in her gums, jaw angle, submandibular region, retro-auricular suboccipital, and temporo-occipital vertex that had been ongoing for four years. As the patient's head pain and facial pain became severe, severe spontaneous pain occurred in the arm, waist, and both lower extremities. This patient's pain in the occipital and neck, spontaneous pain in the face, jaw, and whole body improved with decompression of the GON. Anatomical basis of pain referral to the facial trigeminal area caused by chronic GON entrapment is convergence of nociceptive inflow from high cervical C1-C3 structures and trigeminal orofacial area in the dorsal horn of the cervical spinal cord from the C2 segment up to the medullary dorsal horn (MDH). The major afferent contribution among the suboccipital and high cervical structure is mediated by spinal root C2 that is peripherally represented by the GON. Chronic noxious input from GON entrapment can cause sensitization and hypersensitivity in second order neurons in the trigeminocervical complex (TCC) and MDH in the caudal trigeminal nucleus and high cervical cord. Generalized extension of referred pain due to GON entrapment is thought to involve two possible pathophysiologies. One is the possibility that generalized pain is caused by sensitization of third-order nociceptive neurons in the thalamus. Another speculation is that spontaneous pain may occur throughout the body due to dysfunction of the descending brain stem pain-modulating pathway by sensitization and hyperexcitation of the MDH and trigeminal brainstem sensory nuclear complex (TBSNC).
Objective: Penetrating brain injury occurs when an object enters the skull and pierces the brain. These injuries can damage small or large parts of the brain, are life-threatening, and require emergency care. This study is a summary of penetrating head injuries at our hospital and an analysis of their treatments and prognoses. Methods: Patients with penetrating brain involving the orbit and/or cranial region were recruited among patients with trauma who visited our regional trauma center between 2019 and 2022. Results: Eight patients with penetrating brain injuries were enrolled. One patient was female; the median age was 53 years (range, 24-72 years). Five patients with Glasgow Coma Scale (GCS) scores of 14 or 15 showed no major vessel injury or midline intracranial involvement on imaging and were discharged safely. The other three patients with suspected major vessel injuries and midline involvement did not survive. Conclusion: The greatest influences on patient prognosis were the area of damage and level of consciousness, along with the GCS score at the time of the visit. The probability of survival is extremely low if the midline structure is damaged.
