Iatrogenic Intradural Lumbosacral Cyst Following Epiduroscopy
A 65-year-old lady came to the outpatient department with complaints of low back pain (VAS : 8/10) and stretching discomfort in the left leg since January 2010 when she slipped down on ground. Clinically, she had mild tenderness over L4-L5 and L5-SI regions with paraspinal muscle spasm. Straight leg raising test was normal and she had no neurological deficit. She was managed with pain medications and physiotherapy after checking her X-rays which were normal except findings of left partial laminectomy at L4. She had had a past history of low back pain with left radicular pain, for which two surgeries of microdiscectomy were performed at left L4-5 in May 2008 and November 2008, respectively. She had relief of pain for only 3 months after the first surgery but completely symptom free after the second surgery until the accident on January 2010.\nAs her pain was not relieved, lumbar spine magnetic resonance imaging (MRI) was done with contrast, which showed no recurrence of disc herniation except for the findings of mild adhesion at L4-5 disc and left partial laminectomy of L4 (). She was referred to the pain clinic on June 24, 2010, and underwent endoscopic epidural neuroplasty and transforaminal epidural steroid injection at L4-5 and L5-S1. In prone position, an epidural catheter was inserted into anterior epidural space of L4-5 and L5-S1 levels through the sacral hiatus (). And, pucaine with triamcinolone was injected and adhesiolysis was done. During the procedure, the pain specialists did not experience any specific incident.\nAfter the endoscopic epidural neuroplasty, she complained of increase in the intensity of back pain (VAS : 9/10), over a wide area of low back. She was again put on pain medications for 2 weeks, but not much pain relief and it was decided to take MRI of the lumbosacral spine. MRI showed an intradural cystic lesion, 8 cm in length, spanning from L2-3 to S2-3 level and displacing cauda equina anteriorly, lesion was slightly herniated through the laminectomy defect of left L5. The cyst fluid had the same signal intensity as cerebrospinal fluid, in all the sequences (). She was admitted to our department. Computed tomography myelography confirmed the findings of intradural cyst on the MRI, and contrast media was partially filled up in the cystic cavity of the lower spines (). As conservative treatment did not provide any pain relief, surgery was planned. In operation, the patient was placed in prone position and partial laminectomy of L5 was performed. Opening the dura mater, a large cyst, which presented well demarcated by thin and transparent wall and contained cerebrospinal fluid (CSF), was observed in the dorsal part of the intradural space, compressing and displacing the cauda equina anteriorly. The cauda equina was covered by arachnoid membrane separately (). Fenestration of cystic wall and enlargement of the window were performed. The authors could not find out a connection of the cyst with subarachnoid space intraoperatively. The dura mater was closed water tightly. Before closing the surgical wound, adhesiolysis over the L5 nerve roots was also done. Pathology of cyst wall revealed non-specific fibrous tissue. She had relief of severe back pain postoperatively (VAS : 3/10). Postoperative follow-up MRI disclosed complete disappearance of the intradural cyst ().