A 66-year-old previously well man presented with an 18-year history of upper thoracic spine pain. The pain was initially intermittent and mild, but in the 14 months prior to presentation, it had gradually increased in severity and persistence. The pain radiated to the left side of the neck, and when severe, spread around both sides of the chest. The patient reported two episodes of left arm weakness lasting a few hours with spontaneous resolution, but denied paresthesia, sensory loss, or sphincter disturbance. There was no history of spinal surgery, trauma, or spinal disorders. Clinical examination demonstrated an upper thoracic spine gentle kyphosis. There were no abnormal findings on neurological motor, sensory, and reflex examination. A suboptimal quality MRI of the thoracic spine performed at a different institution was interpreted as an intradural mid-thoracic lesion, with a described intradural extramedullary mass indenting the dorsal aspect of the spinal cord. These findings were initially thought to be a dorsal arachnoid cyst. Repeat MRI at our institution demonstrated findings consistent with the characteristic features of ISCH. T2-weighted images showed anterior kinking and mild flattening of the spinal cord at T5, with widening of the subarachnoid space posterior to the cord and pulsation artifact within the CSF space []. The patient was treated with conservative management, with clinical and radiological surveillance. The patient remained neurologically stable at 4 months after presentation.
A 33-year-old woman visited our hospital for slowly developing left leg weakness for 3 month without history of trauma. She also had progressive right side paresthesia which had developed six years ago. At that time, she had orthostatic headache and examinations to find cerebrospinal fluid (CSF) leakage were performed to rule out spontaneous intracranial hypotension (SIH) at another university hospital. However, there were no specific findings and orthostatic headache improved spontaneously. She has been suffering from nocturia and residual urine sense for five months with no sign of defecation disorder. Neurological examination revealed some indications of Brown-Sequard syndrome, such as decreased pain and temperature sensation (70/100) in the region below right T4 dermatome and muscular weakness (Grade IV) and a poor tactile and vibration sense (70/100) in the region below left T4 dermatome. Deep tendon reflex (DTR) was increased in both lower limbs. The blood test showed no specific finding. Initial MRI showed left antero-lateral displacement of the thoracic spinal cord in T3-4 with expanded subarachnoid space, but there was no abnormal signal change within the spinal cord (). With the diagnosis of ISCH, we performed T3 total laminectomy and found that spinal cord was herniated through the dural defect on the left antero-medial side of T3 level (). After reduction of herniated spinal cord into intra-dural space, we patched dural defect with Tacho-comb® both intradurally and extradurally (). Postoperatively, the patient's symptoms gradually alleviated. Decreased pain and temperature sensation improved by 90% and left side weakness was restored to full muscular strength after 10 days. Dysuria due to the neurogenic bladder was slowly cured and was fully recovered approximately 6 months later.