Outcomes of Microendoscopic Discectomy and Percutaneous Transforaminal Endoscopic Discectomy for the Treatment of Lumbar Disc Herniation: A Comparative Retrospective Study

STUDY DESIGN: Retrospective, case control evaluation of 86 patients who underwent microendoscopic discectomy (MED) and percutaneous transforaminal endoscopic discectomy (PTED) for the treatment of lumbar disc herniation (LDH). PURPOSE: To evaluate the safety and the outcomes of MED and PTED for the treatment of LDH. OVERVIEW OF LITERATURE: MED and PTED are minimally invasive surgical techniques for lower back pain. Studies to date have shown that MED and PTED are safe and effective treatment modalities for LDH. METHODS: A retrospective study was performed in patients with LDH treated with MED (n=50) and transforaminal endoscopic discectomy (PTED; n=36) in our hospital. All patients were followed-up with self-evaluation questionnaires, Oswestry disability index (ODI), medical outcomes study 36-item short form health survey and MacNab criteria. All the patients in both groups were followed up to 12 months after the operation. RESULTS: ODI questionnaire responses were not statistically different between the MED and PTED groups (53.00 vs. 48.72) before treatment. Average scores and minimal disability after 5 days to 12 months of follow-up were 4.96 in the MED group and 3.61 in the PTED group. According to MacNab criteria, 92.0% of the MED group and 94.4% of the PTED group had excellent or good results with no significant difference. CONCLUSIONS: There was no significant difference between MED and PTED outcomes. Further large-scale, randomized studies with long-term follow-up are needed.

Ex Vivo Observation of Human Nucleus Pulposus Chondrocytes Isolated From Degenerated Intervertebral Discs

STUDY DESIGN: We performed an ex vivo study to observe cell morphology and viability of human nucleus pulposus (NP) chondrocytes isolated from degenerated intervertebral discs (IVD). PURPOSE: To better understand the biological behavior of NP chondrocytes in monolayer cultures. OVERVIEW OF LITERATURE: Biological repair of IVDs by cell-based therapy has been shown to be feasible in clinical trials. As one of the most promising transplanting seeds, how the isolated NP chondrocytes behavior ex vivo has not been fully understood. METHODS: Human NP chondrocytes were harvested from 20 degenerated IVDs and cultured in monolayers. Histological and immunochemistry staining was used to detect cell morphology change. Cell viability was studied by analyzing cell cycle distribution and apoptotic rate in the primary and subculuted cells. RESULTS: The round or polygonal primary NP chondrocytes had an average adherence time of 7 days and took nearly 31 days to reach 95% confluence. The spindle-shaped P1 NP chondrocytes increased growth kinetics and took about 12 hours to adhere and 6.6 days to get 95% confluent. Immunochemistry staining of collagen II was positive in the cell cytoplasm. Nearly 90% of the confluent NP chondrocytes stayed in G1 phase while 16% underwent apoptosis. No significant difference of the collagen II expression, cell cycle distribution or the apoptosis indices were detected between the primary and subcultured NP chondrocytes. CONCLUSIONS: Human NP chondrocytes undergo significant morphological change in monolayer cultures. Cell cycle distribution pattern and apoptosis index of the cutured NP chondrocytes potentially influence their clinical transplantation or laboratory use.