【Objective】 To analyze the effect of different range and location of foramen formation on the biomechanics of lumbar spine by three-dimensional finite element analysis （D-FEA）. 【Methods】 A complete model of the lumbar spine （L5）， M0， was developed using the finite element method， and the models M1， M2， M3， M4 and M5 were obtained by sequentially simulating the apical， medial 1/4， 2/4， 3/4 and 4/4 graded resections of the left superior articular process of L5 under a lateral posterior approach with full spinal endoscopy. The displacements were recorded in six conditions： forward flexion， back extension， left and right lateral bending， and left and right lateral rotation. The results were compared between the resected models and the unresected group M0. 【Results】 The three-dimensional finite model of the L4-L5 segment developed in this experiment was valid. Compared with the unresected group M0， the differences in ROM were statistically significant for M1 under forward flexion load （all P<0.05）， M2 under forward flexion and back extension load （all P<0.05）， M3 and M4 under forward flexion， back extension and left and right lateral bending load （all P<0.05）. The differences were statistically significant for M3 and M4 under anterior flexion， posterior extension， left and right lateral flexion， and right rotation loads （all P<0.05）； and for M5 under anterior flexion， posterior extension， left and right lateral flexion and right rotation loads （all P<0.05）. Compared with M0 in the unresected group， the differences were statistically significant for M1 under anterior flexion loads （all P<0.05）， M2 under anterior flexion and left and right rotation loads （all P<0.05）. The differences were statistically significant for M3， M4 and M5 in forward flexion and extension， left and right lateral flexion， and left and right rotational loading （all P<0.05）. 【Conclusion】 In the process of foramen formation， removal of the tip or the medial quarter of the unilateral single segment of the upper articular process of the lumbar spine will affect the stability of the lumbar spine， and increase the maximum value of the stress of the intervertebral disc during the activities of the lumbar spine. Removal of one half or more will significantly damage the biomechanics of the lumbar spine. In order to avoid damaging the normal biomechanics of the lumbar spine， the upper articular process should be protected as much as possible during the whole spinal endoscopic foraminal reconstruction.

【Objective】 To observe the short-term clinical effect of selective nerve block combined with percutaneous posterior endoscopic cervical discectomy （PPECD） in the treatment of cervical spondylotic radiculopathy. 【Methods】 We reviewed 22 patients who received selective nerve block combined with percutaneous posterior endoscopic cervical discectomy （PPECD） for cervical spondylotic radiculopathy from June 2018 to January 2020. We recorded Japanese Orthopaedic Association （JOA） score for treatment evaluation， visual analogue scale （VAS）， the neck disability index score （NDI） preoperative 1 day， postoperative 1 day， 1 month， 3 months， 6 months and 1 year. All data were imported into SPSS26.0 software for analysis and processing. Quantitative data are expressed as mean ± standard deviation. The scores of neck VAS， arm VAS， JOA and NDI were compared at different time points by repeated measurement analysis of variance. Paired t-test was used to compare each time point after operation and the first day before operation. P<0.05 was considered statistically significant， and the modified MacNab standard was used to evaluate the clinical effect at the last follow-up. 【Results】 All operations were successfully completed under ultrasound-guided selective nerve block combined with endoscopic operation. The average operation time was 125.6 minutes. The intraoperative blood loss was 2-100 mL and the average blood loss was 19.1 mL. All patients were followed up for 15-33 months， with an average follow-up of 24.1 months. No patients had spinal cord， nerve root and vascular injury， dural tear or other complications. Compared with the preoperative VAS score， the VAS score of neck and upper arm decreased significantly （P<0.05）， while the JOA score increased significantly （P<0.05）， and the preoperative NDI score decreased significantly （P<0.05）. At the last follow-up， the modified Macnab criteria showed there were 15 excellent cases， 5 good cases， 2 medium cases and 0 poor case. The excellence rate was 91%. Postoperative magnetic resonance imaging and 3D computed tomography reconstruction of the cervical spine showed that the disc had been fully removed and the nerve root compression at the surgical segment was relieved. 【Conclusion】 Ultrasound-guided selective nerve block combined with percutaneous posterior endoscopic cervical discectomy is a safe and effective minimally invasive surgical method for the treatment of cervical spondylotic radiculopathy with reliable short-term efficacy.