BACKGROUND:Current studies on the pathogenesis of ossification of the ligamentum flavum are stil in a preliminary stage, and any single factor influencing incidence of ossification of ligamentum flavum cannot completely explain the pathogenesis of this disease. OBJECTIVE:To summarize the pathogenesis of ossification of ligamentum flavum. METHODS:A computer-based online search was conducted in PubMed, Wanfang, and CNKI databases from January 1990 to December 2015 to screen the relevant literatures regarding the pathogenesis of ossification of the ligamentum flavum using Chinese and English key words“ossification of ligamentum flavum, basic research, pathogenesis, gene, bone morphogenetic protein, osteopontin”. Consequently, 63 eligible literatures were included after the exclusion of the repetitive and old ones. RESULTS AND CONCLUSION:Current studies have shown that ossification of the ligamentum flavum is a disease that results from multiple genetic and environmental causes and is one of the main causes of spinal stenosis. Tissue degeneration, local biomechanics, genetic factors, metabolic disorders, trace elements and vascular inflammation are all shown to be involved in the pathogenesis of ossification of ligamentum flavum.

Objective:To explore the effect of the isolated organ laparoscopic simulation training teaching mode in laparoscopic partial nephrectomy training.Methods:A 39-hour in vitro organ laparoscopic simulation training for 12 urologists who had previously participated in laparoscopic basic technique training but had not independently completed laparoscopic partial nephrectomy in Peking Union Medical College Hospital. The training was conducted twice a week for 3 months from April to June 2022. Five modules, namely ultrasonic knife separation training, ultrasonic knife cutting training, vascularization training, blunt separation training, and partial nephrectomy and wound closure training, were used to provide targeted training for the decomposition of laparoscopic partial nephrectomy, and each training item was assessed and scored according to the scoring rules. At the same time, a questionnaire was used to find out the level of confidence of the 12 physicians in completing the operation and each step in the procedure, so as to assess the changes in the operational skills and psychological quality of the physicians before and after training using paired t-tests or Wilcoxon paired rank sum tests. Results:After the training, the assessment scores of operations in all surgeons were significantly improved. The training scores of ultrasonic knife separation training, ultrasonic knife cutting training, blood vessel nudity training, blunt separation training, and partial nephrectomy and traumatic suture improved from (8.5±0.3), (6.9±0.3), (4.2±0.4), (6.6±0.4), and (5.6±0.7) to (9.8±0.2), (9.6±0.3), (9.3±0.2), (9.4±0.3), and (9.8±0.2), respectively( P<0.05). The average operation time for the partial renal excision and traumatic suture training improved from (47.5±5.8) minutes to (21.6±5.1) minutes( t=18.72, P<0.001). At the same time, self-confidence in completing the operation was also significantly improved from 2(1, 3) before the training to 4(4, 4) after the training ( Z=-3.002, P =0.003). Conclusions:After laparoscopic simulation training with isolated organs, physicians with no previous experience in partial nephrectomy can become proficient in all steps of the procedure, complete the resection of the renal tumor and suturing of the wound within 30 minutes, and gain confidence in the operation of all steps of partial nephrectomy.