Arachnoid calcification producing spinal cord compression.

Arachnoiditis ossificans with progressive syringomyelia and spinal arachnoid cyst

“…[7][8][9][10][11][12][13][14][15][16][17][18][19] AO is considered as the late sequelae of a 3-staged inflammatory process, namely reticulates, arachnoiditis and adhesive arachnoiditis, as proposed by Burton et al 7 Thus, even though the exact cause of AO is still unknown, various factors predisposing to arachnoiditis are implicated. Its exact incidence is uncertain since current knowledge is based on a few published case reports and case series.…”

“…4,5,15,17 Furthermore, helical CT scan and multiplanar reconstruction allow clear delineation of the extent of calcification. 19 Surgical options include laminectomy extending to the arachnoidal pia, combined with extensive resection of soft arachnoiditis, duroplasty and plaque excision. Contrast administration may also assist in ascertaining the extent of arachnoiditis, by enhancing the fibrous scars surrounding the spinal cord.…”

Extensive arachnoid ossification with associated syringomyelia presenting as thoracic myelopathy

“…Type 2 ossification may compress the underlying spinal cord and nerve root, and the corresponding clinical picture suggests myelopathy and radiculopathy. [13,[27][28][29]42,43,54,55,58,61] This condition is rare and has been described in associations with different causes, such as trauma, infection, hemorrhage, and arachnoiditis. Surgical removal of the ossified piece(s) was reported to achieve a high degree of success in halting or reversing neurological deterioration.…”

“…[1,10,37,44,46,54] Although intracranial meningeal ossification has been diagnosed by performing skull roentgenography, [28] plain spine x-ray films rarely demonstrate intraspinal ossification. [1] Myelography is helpful in detecting the level of radiographic block, [3,13,14,27,31] and it sometimes reveals multiple filling defects that correspond to the location of ossified arachnoid plaques. [26,54,58] Currently routine preoperative radiological study in the patients with spinal cord compression is commonly limited to the use of MR imaging which, unfortunately, is not particularly sensitive in detection of small calcifications or ossifications.…”

“…The situation may be further complicated by presence of tight adhesions between the ossification and the spinal cord dura mater or even ingrowing of the bone into the spinal cord. [24,26,27,52,60] In these cases, decompressive surgery of the cord with or without syrinx drainage may be considered a safer choice.…”