[Research of learning curves for unilateral biportal endoscopy technique and associated postoperative adverse events]

To summarize the characteristics of the learning curve and the occurrence of postoperative adverse events during the development of unilateral biportal endoscopy (UBE) technique by comparing the clinical data of early and late patients treated with UBE technique.

All patients who underwent single-level UBE technique between April 1, 2020 and December 31, 2021 were selected as the research subjects. According to the surgical options, all patients were allocated into 3 groups: unilateral decompression and discectomy (UDD) group, unilateral laminotomy for bilateral decompression (ULBD) group, and lumbar intervertebral fusion (LIF) group. The first 60 cases from each group were extracted and ranked orderly. The endoscopic operation time, the times of fluoroscopy during non-internal fixation implantation, the postoperative hospital stay, the drainage volume, the decrease of hemoglobin, the decrease of hematocrit, and the adverse events were collected. In each group, the patients were allocated into early and late cases according to the operation sequence. The first 30 cases of each group were classified as early cases, and the last 30 cases as late cases. Statistical analysis was performed on the above observation indicators between the early and late cases, and a scatter plot of relevant data changes was drawn to observe the change trend.

Compared with the early cases, the endoscopic operation time and the times of fluoroscopy during non-internal fixation implantation of late cases in each group were significantly lower ( P<0.05); the postoperative hospital stay of late cases in LIF group was significantly shorter ( P<0.05); the decreased values of hemoglobin and hematokrit of late cases in ULBD group and LIF group were significantly lower ( P<0.05); the postoperative drainage volume of late cases in ULBD group significantly decreased ( P<0.05). The endoscopic operation time and the times of fluoroscopy during non-internal fixation implantation of 3 groups showed a significant downward trend. The adverse events occurred in 3 early cases and 1 late case of the UDD group, in 6 and 3 cases of the UBLD group, and 8 and 3 cases of the LIF group, respectively. The difference was not significant between the early and late cases ( P>0.05).

In the early practice of UBE technique, there is a high incidence of complication, and the surgical trauma is relatively large, which is related to the lack of understanding of the UBE technique characteristics and insufficient surgical experience. With the proficiency of surgical techniques and accumulation of experience, the operation time and the incidence of postoperative adverse events were significantly reduced.