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Objective The connection between alterations in the disc structure following percutaneous endoscopic lumbar discectomy (PELD) and symptoms in patients postsurgery has not been reported yet. The purpose of the present study was to discuss the potential correlation between the changes in the morphological characteristics of various reference surfaces of the intervertebral disc after percutaneous endoscopic lumbar discectomy (PELD) and clinical outcomes, to identify the morphological parameters that affect efficacy and provide an evidence‐based foundation for assessing postoperative efficacy. Methods From October 2019 to October 2021, after percutaneous endoscopic lumbar discectomy (PELD), 98 individuals were enrolled. MRI DICOM data of the lumbar spine were obtained before and after surgery, specifically around 3 months. The morphological parameters of the operated and adjacent segments of the discs were measured using T2‐weighted images from three reference planes. Outcomes were assessed using the Oswestry disability index (ODI), visual analogue pain scores for the back and leg (VAS‐back/VAS‐leg), Japanese Orthopaedic Association (JOA) scores, and recovery rates. Postoperative changes in disc parameters and outcomes were compared between patients with different severity and types of LDH based on the MSU staging. Patients completed the questionnaire during outpatient follow‐up appointments 3, 6, and 12 months after the surgery. The follow‐up period was 14.69 ± 4.21 months, ranging from 12 to 24 months. Results Parameters such as area and circumference of intervertebral discs in the cross‐section were not associated with the change in the efficacy index. Postoperatively, a negative correlation between the variation of the disc height, disc height index, and protrusion distance and the difference in VAS scores for low back pain at 3 and 6 months was observed among the two sagittal change parameters. Differences between changes in disc imaging parameters and postoperative efficacy were not statistically significant between various types of lumbar disc herniation. Conclusion For the patients after percutaneous endoscopic lumbar discectomy, the changes in parameters such as disc area and circumference in the cross‐sectional plane are not associated with efficacy, and the changes in disc height and herniation distance in the sagittal plane provide a morphologic basis for the assessment of short‐term postoperative efficacy. In addition, the changes in disc morphologic parameters and postoperative efficacy do not differ between various types of lumbar disc herniation.

An optical resolution of 3‐chloromandelic acid (3‐ClMA) using threo‐(1S,2S)‐2‐amino‐l‐p‐nitrophenyl‐1,3‐propanediol ([S,S]‐SA) as a resolving agent was presented. The effects of the type of solvents, the amount of solvent, molar ratio of the resolving agent to racemate and filtration temperature on resolution were investigated. Under the optimal resolution conditions, the content of less soluble salt reached 98%, and the resolution efficiency was as high as 94%. The weak intermolecular interactions (such as hydrogen bond, halogen bond, CH/π and van der Waals interactions) and molecular packing mode in crystal structure of the less soluble salt (R)‐3‐ClMA(S,S)‐SA were investigated. A wall‐like 2‐D hydrogen‐bonding network and hydrophobic structure between hydrogen‐bonding walls were revealed. (S,S)‐SA was also used to resolve 2‐ClMA and 4‐ClMA respectively and the corresponding less soluble salts (R)‐2‐ClMA·(R,R)‐SA and (R)‐4‐ClMA·(R,R)‐SA were obtained using threo‐(1R,2R)‐2‐amino‐l‐p‐nitrophenyl‐1,3‐propanediol ((R,R)‐SA) as a resolving agent. In addition, two other resolving agents, (R)‐ɑ‐phenethylamine ((R)‐PEA) and (R)‐N‐benzyl phenethylamine ((R)‐BPA) reported in the literature for the resolution of 3‐ClMA were examined along with the newly proposed resolving agent, (S,S)‐SA. The crystal structures of the resulting less soluble salts (R)‐3‐ClMA·(S,S)‐SA, (R)‐3‐ClMA·(R)‐PEA and (R)‐3‐ClMA·(R)‐BPA were compared and examined. [ABSTRACT FROM AUTHOR]