A multicenter retrospective clinical study on "symptomatic facet of residual bone mass", a rare complication of percutaneous trasforaminal endoscopic discectomy

Abstract

Objective Retrospective study and report on cases of symptomatic facet of residual bone caused by percutaneous transforaminal endoscopic discectomy (PTED), to analysis of its causes and revision strategies. Methods Seven cases of symptomatic facet of residual bone after PTED were found in six medical centers from July 2015 to November 2017.Weintroduced the course of diagnosis and treatment, to analysis of the causes, clinical features and revision strategies of the rare complication. Results Seven patients came from different medical centers (2 cases in Ningbo No.6 Hospital and 1 case in each of the other medical centers). The average age of the subject is 67.29±9.64 years (range from 57-83 years). Among them there were 1 male and 6 female. PTED was performed for all cases with lumbar disc herniation or stenosis. The operative segments were 1 of L2,3, 2 of L3,4, 3 of L4,5, 1 of L5S1. Symptoms occurred immediately after surgery in all cases except one after a week of operation and another one month later. Two cases were appeared symptom of contralateral irritation, and the rest were aggravated by the original symptoms. Two cerebrospinal fluid leakage caused by bone mass piercing the dural sac. The bone mass compressed the nerve root and caused 1 case of lower limb muscle weakness. Foraminoplasty was performed during PTED in all patients. After CT scan, 5 cases of bone mass were found on the same side of operation, and 2 cases were in the contralateral side. The shortest time for revision was 2 days and the longest 3 months. After conservative treatment, the symptoms were relieved in only one case. Revision surgeries were performed for all the other 6 cases, 2 with microendoscopic discectomy (MED), 1 mobile microendoscopic discectomy (MMED), 1 small incision operation, 1 PTED and 1 with minimal invasive surgery of transforaminal lumbar intervertebral fusion (MIS-TLIF). The VAS scores of low back pain and leg pain was significantly relieved from 8.67±0.52 to 1.50±0.55. Conclusion PTED may lead to residual bone mass in lumbar foraminoplasty. The penetration of the bone mass block into the spinal canal can cause the compression symptoms of the corresponding segment. The patients showed the corresponding spinal canal stenosis and nerve root irritation symptoms. A revision operation is required to remove the oppressed bone mass to relieve the symptoms as soon as possible if the conservative treatment not effective. Key words: Zygapophyseal joint; Multicenter study; Treatment outcome