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Imaging Appearance of Adhesive Arachnoiditis: A Retrospective Review 2014

Category General Spine Tara L. Sabby, MD Jonathan M. Morris, MD John T. Wald, MD Amy L. Kotsenas, MD Purpose Chronic adhesive arachnoiditis (CAA) is a rare entity with potentially devastating clinical consequences. The imaging appearance of interstitial edema and cord swelling due to intradural adhesions may mimic intramedullary spinal cord tumor. The purpose of this presentation is to review the most common clinical causes of CAA and describe the MRI and myelographic imaging appearance of CAA in order to increase radiologist awareness of this challenging diagnosis. We present 29 patients with the common imaging features of advanced CAA in order to better characterize and aid in the detection of this disorder. Materials & Methods At our institution, we have encountered 29 patients since 1995 who have presented with imaging features and clinical diagnosis of severe CAA. A retrospective chart review was performed with attention to clinical presentation, initial differential diagnosis, any interventions performed, and the ultimate cause of the adhesive arachnoiditis. MRI findings were evaluated and categorized. Results The 29 patients ranged in age from 23 to 96 (mean and median of 65 years) with 11 females and 18 males. Underlying causative factors in our patients included prior surgery, subarachnoid hemorrhage, meningitis, Pantopaque myelogram, trauma, Guillain-Barré syndrome, and ankylosing spondylitis. Patients presented with neurologic symptoms including back and radicular pain, sensory myelopathy, weakness, gait disturbance, neurogenic bowel and bladder, and paraplegia. Advanced imaging was performed using MRI with gadolinium in 28 patients and CT myelogram in 6 patients. Imaging characteristics include loculated CSF collections with mass effect on the cord (n=23), nerve root clumping, enhancement, and displacement (n=13), arachnoid septations (n=11), cord atrophy (n=4), syrinx (n=3), intrathecal calcifications (n=3), and cord swelling with increased T2 signal (n=1). Ten patients underwent various surgical treatments, including laminectomy, duraplasty, lysis of adhesions, cyst fenestration, and shunt placement. Despite surgical intervention, most patients only experienced brief improvement with a few showing prolonged modest improvement. Conclusion CAA is a rare cause of devastating neurologic symptoms and chronic pain. The variety of causative etiologies and previously poorly defined imaging characteristics may result in missed or delayed diagnosis. The imaging appearance of intense inflammation and cord swelling may mimic the appearance of an underlying mass. Recognition of the imaging characteristics we describe is essential for making a timely and correct diagnosis and avoiding unnecessary interventions. References Dolan, R. A. (1993). "Spinal adhesive arachnoiditis." Surgical neurology 39(6): 479-484. Killeen, T., A. Kamat, et al. (2012). "Severe adhesive arachnoiditis resulting in progressive paraplegia following obstetric spinal anaesthesia: a case report and review." Anaesthesia 67(12): 1386-1394. Kobayashi, S., K. Kato, et al. (2012). "Experimental Syringohydromyelia Induced by Adhesive Arachnoiditis in the Rabbit: Changes in the Blood-Spinal Cord Barrier, Neuroinflammatory Foci, and Syrinx Formation." Journal of Neurotrauma 29(9): 1803-1816. Mauer, U. M., A. Gottschalk, et al. (2011). "Arachnoscopy: a special application of spinal intradural endoscopy." Neurosurgical Focus 30(4). Mitsuyama, T., S. Asamoto, et al. (2011). "Novel surgical management of spinal adhesive arachnoiditis by arachnoid microdissection and ventriculo-subarachnoid shunting." Journal of clinical neuroscience : official journal of the Neurosurgical Society of Australasia 18(12): 1702-1704. Morisako, H., T. Takami, et al. (2010). "Focal adhesive arachnoiditis of the spinal cord: Imaging diagnosis and surgical resolution." Journal of craniovertebral junction and spine 1(2): 100-106. Rice, I. and M. Y. K. Wee (2004). "Obstetric epidurals and chronic adhesive arachnoiditis." British Journal of Anaesthesia 92(6): 902-U905. Shaw, M. D., J. A. Russell, et al. (1978). "The changing pattern of spinal arachnoiditis." Journal of neurology, neurosurgery, and psychiatry 41(2): 97-107.