Reconstruction of nerve root sheaths for sacral extradural spinal meningeal cysts with spinal nerve root fibers

Abstract

This study analyzed the clinical characteristics and outcomes of sacral extradural spinal meningeal cysts with spinal nerve root fibers treated by reconstruction of the nerve root sheaths. The relationships between the cysts and spinal nerve root fibers were examined microscopically, the cysts were partially excised, and the defects were oversewn to reconstruct the nerve root sheaths. The Improved Japanese Orthopedic Association (IJOA) scoring system was used to evaluate preoperative and postoperative neurological function. Thirty-eight patients were included in this study, with a mean age of 41.4±15.57 years. The mean IJOA score was 18.8±1.32 preoperatively and 19.6±0.65 postoperatively, which was a significant difference (t=-3.77, P=0.001). These results indicate a significant improvement in neurological function after surgery. The most significant improvement in neurological function was sensation (z=-2.86, P=0.004), followed by bowel/bladder function (z=-2.31, P=0.02). The pathophysiological mechanism underlying the formation of SESMCs with SNRFs is congenital weakness of the nerve root sheath [3]. High hydrostatic pressure generated by upright walking and a ball-valve effect result in cyst enlargement [3][4][5]. The walls of the cysts are formed by enlargement of the perineural nerve root sheaths, resulting in alteration of the environment around the spinal nerve root fibers. This alteration causes malfunction of the involved spinal nerve root fibers, similar to axonal transport dysfunction [6]. This malfunction differs from malfunction associated with compression against adjacent bone or other nerve

Electromyography and A Review of the Literature Provide Insights into the Role of Sacral Perineural Cysts in Unexplained Chronic Pelvic, Perineal and Leg Pain Syndromes

“…Sun et al reported that nerve root L5 is frequently involved [24]. In our study, TCs and EMG abnormalities were also frequently detected in the L5 myotomes.…”

“…In aneurysms, years of increased pressure force a weakened vessel wall to enlarge. Similarly, nerve root dilation may require a long period of increased hydrostatic pressure in the spinal canal [2,19,[21][22][23][24].…”

“…They also noted that when cysts are small, the pressure inside may still become critical. Therefore, even very small cysts can be symptomatic, and the initial symptoms in such cases are pain and paresthesia, which can be severely debilitating [19,24,43].…”

“…TCs therefore primarily cause pain and sensory disturbances [24,52]. Hence, EMG may reveal abnormalities in conduction studies of the sensory sural nerve, which contains the fibers of the S1 and S2 nerve root [53].…”

“…This observation is in accordance with the findings reported by Sun et al Large cysts are usually associated with a long symptom-free interval, and if they become symptomatic, the symptoms are more severe and more progressive. The authors used microscopy to identify these large cysts and characterized them as "paraneural cysts" [24]. Figure 1 D shows an axial view of S2 cysts with the S2 nerve roots compressed against the bone.. Large cysts may also compress the neighboring nerve roots and cause bone erosion.…”