Arachnoid web: a mystery unravelled
Keywords:Arachnoid web, MRI, Scalpel sign, Laminectomy, Durotomy, Excision
A 47-year-old lady came with complaints of dull aching low backache and numbness over both the lower limbs since six months, aggravated since one week. She had tenderness over dorsal (D8-D10) and lumbar (L4-L5) spinal and paraspinal regions. Radiographs were inconclusive. Plain and contrast Magnetic resonance imaging (MRI) of the dorso-lumbar (D-L) spine with whole spine screening were also inconclusive initially. But close observation and serial viewing of all the sections revealed features of an arachnoid web at D7-D8 vertebral level. Patient underwent D7, D8 laminectomy with durotomy and arachnoid web excision. She had considerable improvement in her symptoms after the surgery. Hence, prompt recognition and early surgery ensure good outcomes in this uncommon yet relevant clinical entity.
Ali HB, Hamilton P, Zygmunt S, Yakoub KM. Spinal arachnoid web- a review article. J Spine Surg. 2018;4:446-50.
Paramore CG. Dorsal arachnoid web with spinal cord compression: Variant of an arachnoid cyst? Report of two cases. J Neurosurg. 2000;93:287-90.
Yamaguchi S, Hida K, Takeda M, Mitsuhara T, Morishige M, Yamada N, et al. Visualization of regional cerebrospinal fluid flow with a dye injection technique in focal arachnoid pathologies. J Neurosurg Spine. 2015;22:554-7.
Reardon MA, Raghavan P, Carpenter-Bailey K, Mukherjee S, Smith JS, Matsumoto JA, et al. Dorsal thoracic arachnoid web and the "scalpel sign": a distinct clinical-radiologic entity. AJNR Am J Neuroradiol. 2013;34:1104-10.
Grewal SS, Pirris SM, Vibhute PG, Gupta V. Identification of arachnoid web with a relatively novel magnetic resonance imaging technique. Spine J. 2015;15:554-5.
Chang HS, Nagai A, Oya S, Matsui T. Dorsal spinal arachnoid web diagnosed with the quantitative measurement of cerebrospinal fluid flow on magnetic resonance imaging. J Neurosurg Spine. 2014;20:227-33.
Wali AR, Birk HS, Martin J, Santiego-Dieppa DR, Ciacci J. Neurosurgical Management of a Thoracic Dorsal Arachnoid Web: Case Illustration. Cureus. 2019;11:e4945.
Malhotra NR, Shaffrey CI. Intraoperative electrophysiological monitoring in spine surgery. Spine (Phila Pa 1976). 2010;35:2167-79.