Background
When obese patients underwent lumbar discectomy using a microscope, a correlation was found between the operation time and an increase in estimated blood loss according to the increase in body mass index. However, except for minor complications, there was no difference in postoperative outcomes between obese and normal-weight patients. These are the results of microscopic lumbar discectomy in obese patients, but there are no studies on biportal endoscopic lumbar discectomy. The aim of this study was to compare the clinical and radiographic outcomes of microscopic and endoscopic discectomy in obese patients.
Methods
Clinical and radiological data were compared and analyzed in 23 obese patients with a body mass index of >30 kg/m² who underwent microscopic and biportal endoscopic lumbar discectomy. Clinical data on the visual analog scale (VAS), Oswestry Disability Index (ODI), and EuroQol-5D (EQ-5D) scores were measured, and radiological data were measured using magnetic resonance imaging (MRI).
Results
In total, 13 patients who underwent microscopic discectomy and 10 who underwent biportal endoscopic discectomy were enrolled in this study. The VAS, ODI, and EQ-5D scores in both groups improved after surgery compared with those before surgery, although there was no difference between the two groups. Although there was a difference in the incidence of recurrent disc herniation confirmed by MRI after surgery, there was no difference in the number of patients requiring surgery between the two groups.
Conclusions
There were no significant clinical or radiological differences in outcomes between microscopic and biportal endoscopic surgery methods.

Background
Lumbar Arthroscopic Spinal Surgery (LASS) has several advantages compared to conventional procedures in terms of improved visual field, versatility with instrumentation, and ease of handling. Purpose: To report the learning curve of LASS for more than 10 years by an experienced spine surgeon.
Materials and Methods
We retrospectively reviewed medical records of the patients who underwent LASS from Dec. 29th, 2017 to April 31st, 2018. Lumbar Arthroscopic Discectomy (LADi), Lumbar Arthroscopic Decompression (LAD), Lumbar Arthroscopic Foraminoplasty (LAF) were performed. Operation time, the amount of bleeding, the length of hospital stay and the degree of postoperative pain were analyzed to evaluate the learning curve.
Results
28 cases (90.3%) showed satisfactory postoperative results. The operation time per segment was 124.2±58.5 minutes (range 45~247). The mean operation time for LADi was 91.4±62.7 minutes (45~247), for LAD was 136.1±53.8 minutes (68~222 minutes) and for LAF was 135.3±50.6 minutes (72~245), and was indicating a declining trend. In the LAF, the slope of the decline of the learning curve was gentle compared to other operations.
Conclusion
The results of short-term follow-up of LASS are excellent, and it is easy to acquire skills in experienced spine surgeon.