Midline synovial and ganglion cysts causing neurogenic claudication

Abstract

Typically situated posterolateral in the spinal canal, intraspinal facet cysts often cause radicular symptoms. Rarely, the midline location of these synovial or ganglion cysts may cause thecal sac compression leading to neurogenic claudication or cauda equina syndrome. This article summarizes the clinical presentation, radiographic appearance, and management of three intraspinal, midline facet cysts. Three patients with symptomatic midline intraspinal facet cysts were retrospectively reviewed. Documented clinical visits, operative notes, histopathology reports, and imaging findings were investigated for each patient. One patient presented with neurogenic claudication while two patients developed partial, subacute cauda equina syndrome. All 3 patients initially responded favorably to lumbar decompression and midline cyst resection; however, one patient required surgical stabilization 8 mo later. Following the three case presentations, we performed a thorough literature search in order to identify articles describing intraspinal cystic lesions in lateral or midline locations. Midline intraspinal facet cysts represent an uncommon cause of lumbar stenosis and thecal sac compression. Such entities should enter the differential diagnosis of midline posterior cystic lesions. Midline cysts causing thecal sac compression respond favorably to lumbar surgical decompression and cyst resection. Though laminectomy is a commonly performed operation, stabilization may be required in cases of spondylolisthesis or instability.

Keywords: Claudication; Cyst; Facet; Ganglion; Intraspinal; Laminectomy; Midline; Neurogenic; Synovial.

Figure 1

T2-weighted imaging of case 2. A, B: In the preoperative images, sagittal (A) and axial (B) T2 weighted magnetic resonance imaging displays a large intraspinal cystic lesion at the L4-5 level causing stenosis and thecal sac compression. The cystic lesion appears to have an eccentric component extending towards the left facet joint; C, D: Post-operative imaging following decompressive laminectomy and cyst excision. Bilateral laminectomies at L4-5 and cyst resection provide adequate decompression of the dorsal thecal sac and cauda equina, as shown in sagittal (C) and axial (D) images.

Figure 2

Case 2, pathological findings of midline ganglion cyst (hematoxylin eosin staining, × 400). Photomicrograph (original magnification × 400) reveals proteinaceous material (arrow) surrounded by dense fibro-connective tissue (asterisk), without the presence of synovial epithelium. These findings confirm the diagnosis of a ganglion cyst.