630 - Dorsal Arachnoid Web and Scalpel Sign

Case Diagnosis: Dorsal Arachnoid Web

Case Description: A 77-year-old male presented with left facial and hand pain, accompanied by left arm and leg weakness. History of inclusion body myositis and a previous hemiparesis stroke. On PE, reduced sensation in left UE and LE, muscle strength 4/5 in left UE and LE. DTR absent bilaterally in UEs and LEs, Babinski and Hoffman signs negative bilaterally. Thoracic MRI revealed dorsal cord flattening centered at T2-3, exhibiting a Scalpel Sign pattern, without discrete cord signal abnormality. His pain likely due to central pain syndrome and was treated with pregabalin and amitriptyline. He was referred to Neurosurgery. It was determined that the weakness in the left LE was more likely related to inclusion body myositis, as there was no clear evidence of upper motor neuron signs. Surgical intervention was not recommended. At a one-year follow-up, there was no significant change in sensation or muscle strength. His pain had improved with medications.

Discussions: Arachnoid web is a rare and complex spinal pathology. The exact cause is not fully understood. several theories and factors have been proposed that may contribute to their development, which include Congenital Abnormalities, Trauma, Inflammatory Conditions and idiopathy. Recognizing its potential to lead to myelopathy and related symptoms is crucial. Timely diagnosis through MRI and CT myelography, is essential for tailored intervention, which can range from conservative measures to surgical decompression.

Conclusions: Arachnoid webs are a rare condition. The presence of the Scalpel Sign on MRI and CT myelogram can serve as a distinct feature for diagnosis. Conservative treatment is appropriate when there is no evidence of myelopathy, while surgical intervention may be considered if myelopathy is present. Further research is needed to gain a more comprehensive understanding of the precise mechanisms behind the formation of arachnoid webs.