[Contralateral endoscopic approach for lumbar foraminal stenosis using unilateral biportal endoscopic surgery].

OBJECTIVE: To assess the feasibility and imaging outcomes of unilateral biportal endoscopic technique in the treatment of lumbar foraminal stenosis through contralateral approach. METHODS: The clinical data of 33 patients with lumbar foraminal stenosis treated with unilateral biportal endoscopic technique from January 2021 to July 2022 were retrospectively analyzed. There were 17 males and 16 females;age ranging from 34 to 72 years old with an average of (56.00±7.89) years old;operation time and perioperative complications were recorded;visual analogue scale (VAS) of pain was recorded, to evaluate the degree of low back pain and lower extremity pain, and Oswestry disability index (ODI) to evaluate the lumbar spine function. At the latest follow-up, the modified Macnab score was used to evaluate the clinical efficacy. RESULTS: All patients successfully completed the operation. The operation time ranged from 47 to 65 minutes, with an average of (56.10±5.19) minutes. The postoperative follow-up ranged from 12 to 18 months, with an average of (14.9±2.3) months. The VAS of low back and lower extermity pain before operation were (7.273±1.442) and (7.697±1.447) scores, ODI was (69.182±9.740)%. Postoperative lumbocrural pain VAS were (3.394±0.966) and (2.818±0.727) scores, ODI was (17.30±4.78) %. At the latest follow-up, VAS of back and lower extermity pain was (2.788±0.650) and (2.394±0.704) scores, ODI was (14.33±350)%. There were significant differences in VAS of low back and lower extremity pain and ODI before and after operation(P<0.05). At the latest follow-up, according to the modified Macnab criteria, 24 patients got excellent result, 5 as good, 2 as fair, and 2 as poor. CONCLUSION: Unilateral biportal endoscopic treatment of lumbar foraminal stenosis through the contralateral approach is a safe and efficient method, with few complications, quick postoperative recovery, and satisfactory clinical outcomes. During the follow-up period, no iatrogenic lumbar instability was observed.

Effects of a bone graft substitute consisting of porous gradient HA/ZrO2 and gelatin/chitosan slow-release hydrogel containing BMP-2 and BMSCs on lumbar vertebral defect repair in rhesus monkey.

Dense biomaterial plays an important role in bone replacement. However, it fails to induce bone cell migration into graft material. In the present study, a novel bone graft substitute (BGS) consisting of porous gradient hydroxyapatite/zirconia composite (PGHC) and gelatin/chitosan slow-release hydrogel containing bone morphogenetic protein 2 and bone mesenchymal stem cells was designed and prepared to repair lumbar vertebral defects. The morphological characteristics of the BGS evaluated by a scanning electron microscope showed that it had a three-dimensional network structure with uniformly distributed chitosan microspheres on the surfaces of the graft material and the interior of the pores. Then, BGS (Group A), PGHC (Group B), or autologous bone (Group C) was implanted into lumbar vertebral body defects in a total of 24 healthy rhesus monkeys. After 8 and 16 weeks, anteroposterior and lateral radiographs of the lumbar spine, microcomputed tomography, histomorphometry, biomechanical testing, and biochemical testing for bone matrix markers, including Type I collagen, osteocalcin, osteopontin, basic fibroblast growth factor, alkaline phosphatase, and vascular endothelial growth factor, were performed to examine the reparative efficacy of the BGS and PGHC. The BGS displayed excellent ability to repair the lumbar vertebral defect in rhesus monkeys. Radiography, microcomputed tomography scanning, and histomorphological characterization showed that the newly formed bone volume in the interior of the pores in the BGS was significantly higher than in the PGHC. The results of biomechanical testing indicated that the vertebral body compression strength of the PGHC implant was lower than the other implants. Reverse-transcription polymerase chain reaction and western blot analyses showed that the expression of bone-related proteins in the BGS implant was significantly higher than in the PGHC implant. The BGS displayed reparative effects similar to autologous bone. Therefore, BGS use in vertebral bone defect repair appears promising.

Evaluation of porous gradient hydroxyapatite/zirconia composites for repair of lumbar vertebra defect in dogs.

OBJECTIVE: To evaluate the effects of porous gradient composites with hydroxyapatite/zirconia and autologous iliac in repair of lumbar vertebra body defects in dogs. METHODS: (1) New porous gradient hydroxyapatite/zirconia composites were prepared using foam immersion, gradient compound and high temperature sintering; (2) A total of 18 adult beagle dogs, aged five to eight months and weighted 10-13 kg, were randomly assigned into two subgroups, which were implanted with new porous gradient hydroxyapatite/zirconia composites (subgroup A in 12) or autologous iliac bone (subgroup B in 6); (3) The post-operative data were analyzed and compared between the subgroups to repair the vertebral body defect by roentgenoscopy, morphology and biomechanics. RESULTS: The porosity of new porous gradient hydroxyapatite/zirconia composites is at 25 poles per inch, and the size of pores is at between 150 and 300 µm. The post-operative roentgenoscopy displayed that new-bone formation is increased gradually, and the interface between composites and host-bone becomes became blur, and the new-bone around the composites were integrated into host-bone at 24 weeks postoperatively in subgroup A. As to subgroup B, the resorption and restructure were found at six weeks after the surgery, and the graft-bone and host-bone have been integrated completely without obvious boundary at 24 weeks postoperatively. Histomorphologic study showed that the amount of bone within pores of the porous gradient hydroxyapatite/zirconia composites increased continuously with a prolonged implantation time, and that partial composites were degradated and replaced by new-bone trabeculae. There was no significant difference between subgroups (P > 0.05) in the ultimate compressive strengths. CONCLUSION: New porous gradient hydroxyapatite/zirconia composites can promote the repair of bony defect, and induce bone tissue to ingrow into the pores, which may be applied widely to the treatment of bony defect in the future.