Post-discectomy pseudocyst after transformimal percutaneous endoscopic discectomy: two cases reports and related literature review

Objective To investigate the clinical features and treatment of post-discectomy pseudocyst after transformimal percutaneous endoscopic discectomy. Methods Two patients from two different hospitals were retrospectively studied. One was male whose age was 26 years old, and the other was female whose age was 34 years old. Both cases presented with radiating unilateral leg pain and were diagnosed with ipsilateral herniated nucleus pulposus at L4,5 based on MRI. They both experienced recurrent symptoms after successful transformimal percutaneous endoscopic discectomy. The mean time to relapsing radiculopathy was 1.5 months (1-2 months) with 8 on the visual analogue scale scores. On the postoperative MRI, cystic lesion of T2WI high (similar to cerebrospinal fluid) and T1W low at discectomy site was found in both patients. Results One case was conducted with partial hemilaminectomy and discectomy. A dark red cystic mass containing old bloody fluid was found intra-operatively, and the histology of the cyst wall showed nucleus-like tissue, and inflammatory granulation tissue containing neovascularization and inflammatory cell infiltration in some area. The other case was conducted transformimal percutaneous endoscopic discectomy again, and dark red granulation tissue was found intra-operatively, and the histology of capsule wall showed fibrous connective tissue. Both cases achieved successful pain relief after the second surgeries. And MRI demonstrated the pseudocysts disappeared 3 months follow-up postoperatively. Conclusion Symptomatic post-discectomy pseudocyst is a rare complication after transformimal percutaneous endoscopic discectomy. It usually occurs in the early period postoperatively. MRI can confirm the diagnosis. Patients with failed conservative treatment can treat with surgery, and the prognosis is good. Key words: Diskectomy; Endoscopy; Postoperative complications