Objective To assess the mid-term effectiveness of anterior decompression and fusion with nano-hydroxyapatite/polyamide 66 (n-HA/PA66) cage in treatment of cervical spondylotic myelopathy. Methods A retrospective study was made on 48 patients with cervical spondylotic myelopathy who underwent anterior decompression and fusion with n-HA/PA66 cage between August 2008 and January 2010. There were 33 males and 15 females with an average age of 54.5 years (range, 42-72 years). The disease duration was 3-12 months (mean, 6 months). The affected segments included 35 cases of single segment (C3, 4 in 7, C4, 5 in 18, and C5, 6 in 10) and 13 cases of double segments (C3-5 in 7 and C4-6 in 6). Of 48 patients, 28 was diagnosed as having intervertebral disc protrusion, 12 as having ossification of posterior longitudinal ligament, and 8 as having vertebral osteophyte; 35 patients underwent single segmental anterior corpectomy and fusion, and 13 patients underwent single segmental anterior discectomy and fusion. The pre- and post-operative radiographs (cervical anteroposterior and lateral X-ray films and three-dimensional CT scans) were taken to measure the segmental height and lordosis angle. Brantigan et al assessment standard and visual analogue scale (VAS) and Japanese Orthopaedic Association (JOA) scores were used to evaluate the graft fusion and the improvement of clinical symptoms, respectively. Results All patients were followed up for 46 months on average (range, 36-54 months). No cage breaking, displacement, or sliding was found. At last follow-up, 36 cases were rated as Brantigan grade E, 10 cases as grade D, and 2 cases as grade C; the fusion rate was 96%. Both segmental height and lordosis angle were corrected significantly at immediate and 6 months after operation and last follow-up than those before operation (P lt; 0.05), but no significant difference was found among different time points after operation (P gt; 0.05). At last follow-up, the cage subsidence was (1.3 ± 1.0) mm. The VAS and JOA scores at 6 months after operation and last follow-up were significantly improved when compared with preoperative scores (P lt; 0.05), and the scores at last follow-up were superior to ones at 6 months after operation (P lt; 0.05). Conclusion The mid-term effectiveness of anterior decompression and fusion with the n-HA/PA66 cage in patients with cervical spondylotic myelopathy is satisfactory because it can effectively restore and maintain segmental height and lordosis angle and promote osseous fusion.
Objective To evaluate the security and effectiveness of nano-hydroxyapatite/polyamide 66 (n-HA/PA66) cage in reconstruction of spinal stabil ity after resection of spinal tumor. Methods Between January 2008 and December2009, 11 patients with spinal tumor underwent surgical resection and strut graft with n-HA/PA66 cage. There were 6 males and 5 females with an average age of 44.5 years (range, 16-61 years). The average disease duration was 6.8 months (range, 2-14 months). The locations of lesions included cervical spine (2 cases), thoracic spine (6 cases), and lumbar spine (3 cases). Among them, there were 5 metastatic carcinomas, 2 giant cell tumors, 1 osteoblastsarcoma, 1 chondrosarcoma, and 2 non-Hodgkin lymphoma. According to Frankel criteria for nerve function classification, there were 1 case of grade A, 3 cases of grade B, 2 cases of grade C, 2 cases of grade D, and 3 cases of grade E. Results Incisions healed by first intention in all patients, no operative or postoperative compl ication occurred. Four cases of metastatic carcinoma died of primary disease during 5-9 months after operation. Seven cases were followed up 14.4 months on average (range, 10-18 months). All patients gained significant improvement of the neurological function at 3 months after operation. All cases obtained bone fusion and good spinal stabil ity without displacement and subsidence of the n-HA/PA66 cage. The intervertebral height of the adjacent segments was (110.5 ± 16.1) mm at 3 months after operation and (109.4 ± 16.2 ) mm at the final follow-up, showing significant differenecs when compared with the preoperative height [(97.5 ± 15.4) mm, P lt; 0.05], but no significant difference between 3 months after operation and the final follow-up. In 2 patients undergoing surgery via anterior approach, bilateral pleural effusion on both sides occurred and were cured after closed thoracic drainage. During the follow-up, 2 cases (1 chondrosarcoma and 1 giant cell tumor) relapsed and underwent reoperations. Conclusion n-HA/PA66 cage can provide satisfactory bone fusion and ideal spinal stabil ity without increasing the risk of recurrence and compl ications during the surgical treatment of spinal tumors. It is an idealselection for reconstruction of spinal stability.
Objective To study the clinical effects of artificial vertebral laminae of the biomimetic nano-hydroxyapatite/polyamide 66 (n-HA/PA66) composites in prevention of the scar formation in lumbar spinal canal and the reconstruction of posterior vertebral laminae structure. Methods From January 2003 to December 2005, 23 patients were treated with artificialvertebral laminae of the biomimetic n-HA/PA66 composites. There were 16 males and 7 females, aging from 48 to 76 years with an average of 59 years. Of 23 cases,11 cases had spinal stenosis, 7 cases had spinal stenosis with spondylolysis, 3 cases had lumbar disk herniation and 2 cases had spinal tumor. Twenty cases of vertebral laminae were reconstructed by 1 artificial vertebral laminae and 3 cases by 2.The affected locations were C5,6,L1 and L2 in 1 case respectively; L4,5 in 5 cases; L4-S1 in 9 cases; and L5, S1 in 6 cases. Results First intension was achieved in 22 cases and infection occured in 1 case.In the period of follow-up for all cases lasted from 5 to 24 months,the postoperative CT showed that the nHA/PA66 artificial vertebral laminae enlarged the spinal canal. MRI showed little scar formation and adhesion in the lumbar spinal canal. CT showed illdefined boundary between artificial vertebral laminae and recipient vertebral laminae. No neural symptoms occured in all cases except onebecause of stretch injury of nerve root in operation. Also no rejection reaction was observed. Conclusion The artificial vertebral laminae of the biomimetic nHA/PA66 composites can effectively prevent the compression to the nerve root and dural sac from the scar and restore the vertebral laminae.
ObjectiveTo compare the biomechanical differences between the kidney-shaped nano-hydroxyapatite/polyamide 66 (n-HA/PA66) Cage and the bullet-shaped n-HA/PA66 Cage. MethodsL2-L5 spinal specimens were selected from 10 adult male pigs. L2, L3 and L4, L5 served as a motor unit respectively, 20 motor units altogether. They were divided into 4 groups (n=5):no treatment was given as control group (group A); nucleus pulposus resection was performed (group B); bullet-shaped Cage (group C), and kidney-shaped Cage (group D) were used in transforaminal lumbar interbody fusion (TLIF) through left intervertebral foramen and supplemented by posterior pedicle screw fixation. The intervertebral height (IH) and the position of Cages were observed on the X-ray films. The range of motion (ROM) was measured. ResultsThere was no significant difference in the preoperative IH among 4 groups (F=0.166, P=0.917). No significant change was found in IH between at pre- and post-operation in group B (P>0.05); it increased after operation in groups C and D, but difference was not statistically significant (P>0.05). There was no significant difference in the postoperative IH among groups B, C, and D (P>0.05). The distance from Cage to the left margin was (3.06±0.51) mm in group C (close to the left) and (5.68±0.69) mm in group D (close to the middle), showing significant difference (t=6.787, P=0.000). The ROM in all directions were significantly lower in groups C and D than in groups A and B (P<0.05), and in group A than in group B (P<0.05). The right bending and compression ROM of group C were significantly higher than those of group D (P<0.05), but no statistically significant difference was found in the other direction ROM (P>0.05). ConclusionThe bullet-shaped and kidney-shaped Cages have similar results in restoring IH and maintaining the stability of the spine assisted by internal fixation. Kidney-shaped Cage is more stable than bullet-shaped Cage in the axial compression and the bending load opposite implant, it can be placed in the middle and back of the vertebral body more ideally.
Objective To investigate the safety of nano-hydroxyapatite/polyamide 66 (n-HA/PA66) bioactive support in bone grafting and fusion for elderly patients with lumbar tuberculosis, and to analyze its effectiveness and advantages by comparing with autologous iliac bone grafting. Methods A retrospective analysis was performed on 48 elderly patients with lumbar tuberculosis who met the selection criteria between January 2017 and January 2020. The patients all underwent one-stage posterior pedicle screw internal fixation combined with anterior lesion removal and bone grafting and fusion, of which 23 cases applied n-HA/PA66 bioactive support+allogeneic bone graft (n-HA/PA66 group) and 25 cases applied autologous iliac bone graft (autologous iliac bone group). There was no significant difference between the two groups in gender, age, bone density, disease duration, lesion segment, and preoperative pain visual analogue scale (VAS) score, Japanese Orthopaedic Association (JOA) score, and Cobb angle (P>0.05). The operation time, intraoperative blood loss, and postoperative complications, as well as the VAS score, JOA score, American Spinal Injury Association (ASIA) spinal cord injury grading, Cobb angle, and bone fusion were recorded and compared between the two groups. Results The operations were completed successfully in both groups. n-HA/PA66 group had significantly less operation time and intraoperative blood loss than the autologous iliac bone group (P<0.05). All patients were followed up 12-24 months, with an average of 15.7 months. And the difference in follow-up time between the two groups was not significant (P>0.05). Postoperative complications occurred in 3 cases (13%) in the n-HA/PA66 group and 10 cases (40%) in the autologous iliac group, and the difference in the incidence of complications between the two groups was significant (χ2=4.408, P=0.036). The postoperative VAS scores and JOA scores significantly improved when compared with the preoperative scores in both groups (P<0.05), and the difference was significant (P<0.05) between 2 weeks after operation and the last follow-up. The difference in VAS score at 2 weeks after operation was significant between the two groups (P<0.05), and there was no significant difference (P>0.05) at the other time points. At last follow-up, according to the ASIA grading, the effective improvement rate was 86% (18/21) in the n-HA/PA66 group and 90% (18/20) in the autologous iliac group, with no significant difference (χ2=0.176, P=0.675). Imaging review showed that grade Ⅰ bony fusion was obtained in both groups, and the fusion time of bone graft in the n-HA/PA66 group was significantly longer than that in the autologous iliac bone group (P<0.05). There was no significant difference in the Cobb angle at each time point between the two groups (P>0.05). No recurrence of tuberculosis, loosening or fracture of the internal fixator, or displacement of the bone graft was observed during follow-up. Conclusion In elderly patients with lumbar spine tuberculosis, the n-HA/PA66 bioactive support combined with allogeneic bone graft can effectively restore and maintain the fusion segment height and physiological curvature of the lumbar spine, and the fusion rate of bone graft is similar to that of autologous iliac bone, which can achieve better effectiveness.