Response to “Syringomyelia secondary to ‘occult’ dorsal arachnoid webs: Report of two cases with review of literature” by Sayal et al.

Dear Dr. Goel,

We read with interest the recent article by Sayal et al.,[1] “Syringomyelia secondary to ‘occult’ dorsal arachnoid webs: Report of two cases with review of literature.” They described the phenomenon of arachnoid webs being the cause of syringomyelia though the webs were not evident on magnetic resonance imaging. Their two cases are indeed compelling, and we agree with their conclusions. However, their literature review omitted our 2016 article in World Neurosurgery:[1] “Nuances in localization and surgical treatment of syringomyelia associated with fenestrated and webbed intradural spinal arachnoid cyst: A retrospective analysis.”[2]

We reported a series of seven patients with syringomyelia secondary to spinal webbed arachnoid cysts, three of which were undetected on imaging studies. While some authors differentiate between the terms, “webs,” “fenestrations,” and traditional arachnoid cysts, we believe that they are along the same spectrum and follow the same pathophysiology in causing syringomyelia.

In fact, our report cited the same reference by Paramore[3] that Sayal et al. cited, which mentioned these arachnoid “webs” as variants of traditional arachnoid cysts, and together in the same spectrum, following the same pathophysiology, to be a cause of syringomyelia.

We agree that with careful planning and complete resection of the sac to restore normal cerebrospinal fluid flow, neurosurgeons can consistently achieve good radiologic and functional outcomes in their patients.

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