Axial instrument strategy for atlantoaxial dislocation with complex artery variation / 中华骨科杂志

Objective:To evaluate the axial instrument strategy for atlantoaxial dislocation with complex vertebral artery variation.Methods:A total of 55 patients with atlantoaxial dislocation who underwent surgical treatment from January 2019 to December 2021 were retrospectively analyzed, including 14 males and 41 females, aged 54.0±12.8 years (range, 22-78 years). Among these patients, 10 patients with unilateral vertebral artery high ride with contralateral vertebral artery occlusion, 30 patients with bilateral vertebral artery high ride with single dominant vertebral artery, 15 patients with bilateral vertebral artery high ride. All patients underwent posterior reduction and internal fixation. Visual analogue scale (VAS) and Japanese Orthopaedic Association (JOA) score were used to evaluate the postoperative efficacy.Results:All patients completed the surgery successfully with a follow-up time of 14.6±5.5 months (range, 6-24 months). C 2 pedicle screw fixation was performed on the non-dominant side of unilateral vertebral artery high ride and the non-dominant side of bilateral vertebral artery high ride with one dominant vertebral artery (40 vertebraes). The dominant side of unilateral high vertebral artery and bilateral high vertebral artery with one dominant vertebral artery was fixed with C 2 medial "in-out-in" screw (10 vertebraes), C 2 isthmus screw (21 vertebraes), C 2 without screw (9 vertebraes) only extended the fixed segment. For bilateral vertebral artery high ride patients, one side was used C 2 "in-out-in" pedicle screws (right 10 vertebraes, left 5 vertebraes), and the other side was fixed with C 2 medial "in-out-in" screw (8 vertebraes), C 2 isthmus screw (5 vertebraes), C 2 without screw only extended the fixed segment (2 vertebraes). The JOA scores were 8.5±1.8, 13.9±1.3, and 14.4±1.1 preoperatively, 6 months postoperatively, and at the final follow-up, respectively, with statistically significant differences ( F=279.40, P<0.001). JOA at 6 months postoperatively and at the final follow-up was greater than preoperatively, and the differences were statistically significant ( P<0.05), whereas the differences in JOA scores at 6 months postoperatively and at the final follow-up was not statistically significant ( P>0.05). Preoperative, 6 months postoperatively and final follow-up cervical VAS scores were 3.7±1.9, 2.1±0.9 and 1.6±1.0, respectively, with statistically significant differences ( F=39.53, P<0.001). The cervical VAS at 6 months postoperatively and at the last follow-up was less than that before surgery, and the differences were statistically significant ( P<0.05). Cervical VAS scores at 6 months postoperatively were greater than at the last follow-up, with a statistically significant difference ( P<0.05). Conclusion:For patients with atlantoaxial dislocation with complex vertebral artery variation, C 2 lateral "in-out-in" screw, C 2 medial "in-out-in" screw, isthmus screw fixation or C 2 without screw only extended the fixed segment can obtain good clinical efficacy.

Anterior cervical release and posterior fixation for the treatment of irreducible atlantoaxial dislocation with retropharyngeal internal carotid artery / 中华骨科杂志

Objective:To investigate the clinical effect of anterior cervical release and posterior fixation in the treatment of irreducible atlantoaxial dislocation with retropharyngeal internal carotid artery.Methods:Thirteen patients with irreducible atlantoaxial dislocation of retropharyngeal internal carotid artery from January 2015 to July 2019 were treated with anterior cervical release and posterior fixation. There were 8 males and 5 females, aged from 34 to 65 years with an average of 46.1±12.6 years. Positive, lateral and dynamic X-ray films, MR and CTA were performed before operation. There were 4 cases with bilateral retropharyngeal internal carotid artery and 9 cases with unilateral retropharyngeal internal pharyngeal artery. The time of operation, the amount of bleeding and intraoperative and postoperative complications were recorded. The main observations were Japanese Orthopaedic Association (JOA) score, atlantodental interval (ADI), Chamberlain line (CL), and changes in the morphology of the retropharyngeal internal carotid artery and implant fusion.Results:All the operations completed successfully. The operation time was 210-260 min, the average was 245±21 min; the blood loss was 350-600 ml, the average blood loss was 490±107 ml. There was no injury of internal carotid artery, vertebral artery, spinal cord or nerve root during the operation. All patients were followed up for 9 to 24 months, with an average of 15.1±6.2 months. Preoperative JOA score was 6.9±2.3 points, 1 month after operation was 13.5±2.5 points, and the last follow-up was 14.3±2.1 points. The difference was statistically significant ( F=30.91, P<0.001). The difference between 1 month after operation and before operation was statistically significant ( P<0.001), and the improvement rate of JOA score was 75.6%±15.2%. There was no significant difference between the last follow-up and 1 month after operation ( P>0.05). The preoperative ADI was 8.9±2.2 mm, 1 month after operation was 1.1±0.8 mm, and the last follow-up was 1.2±0.9 mm. The difference was statistically significant ( F=114.69, P<0.001). The difference between 1 month after operation and before operation was statistically significant ( P<0.001), and ADI had returned to normal level. There was no significant difference between the last follow-up and 1 month after operation ( P>0.05). The preoperative CL was 11.7±4.8 mm, 1 month after operation was 1.6±2.1 mm, and the last follow-up was 1.8±2.3 mm. The difference was statistically significant ( F=34.19, P<0.001). The difference between 1 month after operation and before operation was statistically significant ( P<0.001), and the position of odontoid process returned to normal level. There was no significant difference between the last follow-up and 1 month after operation ( P>0.05). Bone graft fusion was received at 6 to 12 months after operation, with an average of 10.2 months. Conclusion:CTA examination should be performed before anterior release of atlantoaxial dislocation to understand the position and shape of internal carotid artery. Anterior cervical release combined with posterior bone graft fusion is an effective method for the treatment of irreducible atlantoaxial dislocation with retropharyngeal internal carotid artery without increasing the risk of internal carotid artery injury.

The effect of in-out-in axis pedicle screws on the vertebral artery in the posterior occipitocervical surgery / 中华创伤骨科杂志

Objective:To observe the effect of insertion of in-out-in axis pedicle screws on the vertebral artery in the posterior occipitocervical surgery for atlantoaxial subluxation or instability.Methods:The data of 52 patients with atlantoaxial dislocation or instability were analyzed who had been treated by internal fixation with in-out-in pedicle screws in the posterior occipitocervical surgery from January 2015 to February 2021 at Department of Spine and Spinal Cord Surgery, Henan Provincial People's Hospital. There were 30 males and 22 females, aged from 17 to 65 years (mean, 41.2 years). There were 26 cases of unilateral vertebral artery high-riding, 3 cases of bilateral high-riding, 19 cases of unilateral narrow pedicle due to C2 and C3 fusion, and 4 cases of bilateral narrow pedicles. X-ray, CTA and MRI were performed before and 3 days after surgery. The patients' clinical symptoms were recorded. CTA was used to measure the diameter of the vertebral artery at the transverse foramina of C 2 and C 3 and to observe the effect of in-out-in screws on the morphology of the vertebral artery. X-ray and CT examinations were performed at 6 months after surgery to observe the bone fusion. Results:The surgery went on uneventfully in all the patients. In the 9 cases undergoing anterior and posterior surgery, the operation time averaged 271.2 min (from 213 to 352 min) and the bleeding volume 471.5 mL (from 230 to 830 mL). In the 43 cases undergoing posterior surgery, the operation time averaged 171.6 min (from 131 to 226 min) and the bleeding volume 395.9 mL (from 170 to 660 mL). There was no such complication as spinal or vascular injury. The CTA reexamination 3 days after surgery showed that the diameter of the vertebral artery was (2.92±0.55) mm and (3.04±0.54) mm, respectively at the cervical 2 and 3 transverse foramina, showing no significant change compared with the preoperative values [(2.91±0.68) mm and (3.11±0.50) mm] ( P>0.05) and that the vertebral artery was displaced externally and inferiorly in 21 cases. Follow-ups for all patients ranged from 7 to 24 months (mean, 11 months). At 6 months after surgery, bone fusion was observed by imaging and no breakage or displacement of the internal fixation was observed. Conclusion:The in-out-in pedicle screws in the posterior occipitocervical surgery may have little impact on the vertebral artery, leading to reliable clinical outcomes.

Surgical timing for acute traumatic central cord syndrome / 中华创伤骨科杂志

Objective:To investigate the effects of different surgical time points on the treatment efficacy of acute traumatic central cord syndrome (ATCCS).Methods:Retrospectively analyzed were the 84 ATCCS patients who had been treated at Department of Spinal Surgery, Henan Provincial People's Hospital from January 2013 to February 2021. According to the surgical timing, the patients were divided into 3 groups. In group A (surgery < 48 hours) of 16 cases, there were 11 males and 5 females, aged from 43 to 76 years; in group B (surgery within 3 to 7 days) of 41 cases, there were 31 males and 10 females, aged from 41 to 78 years; in group C (surgery within 8 to 14 days) of 27 cases, there were 15 males and 12 females, aged from 46 to 83 years. Anterior, posterior or combined anterior and posterior approaches were used according to their specific condition. The American Spinal Injury Association (ASIA) motor scores and Japanese Orthopaedic Association (JOA) scores at admission, 7 days and 12 months after operation, postoperative ICU duration, and complications were compared among the 3 groups.Results:There were no significant differences in the preoperative general information or surgical approaches among the 3 groups, showing they were comparable ( P> 0.05). In all patients, the ASIA motor scores and JOA scores at 7 days and 12 months after operation were significantly better than those at admission, and the ASIA motor scores and JOA scores at 12 months after operation were significantly better than those at 7 days after operation ( P<0.01). There was no significant difference in the ASIA motor score or JOA score between the 3 groups at 7 days or 12 months after operation ( P>0.05). The postoperative ICU duration in group A was 42 (26, 61) h, significantly longer than 23 (16, 35) h in group B and 24 (14, 38) h in group C ( P<0.05). There were no deaths in the 84 patients; there was no significant difference in the overall incidence of serious complications or in that of general complications among the 3 groups ( P>0.05). Conclusions:Surgery is safe and effective for ATCCS. However, decompression surgery within 2 weeks may achieve better outcomes.

Efficacy comparison of posterior atlas uniaxial and polyaxial screw instrumentation and fusion with bone graft for Gehweiler type IIIb atlas fracture / 中华创伤杂志

Objective:To compare the efficacy of posterior atlas uniaxial and polyaxial screw instrumentation and fusion with bone graft for Gehweiler type IIIb atlas fracture.Methods:A retrospective cohort study was performed to analyze the clinical data of 36 patients with Gehweiler type IIIb atlas fracture admitted to Henan Provincial People′s Hospital from January 2015 to October 2020. There were 29 males and 7 females, with age range of 23-82 years [(48.8±15.5)years]. All patients were treated with posterior atlas screw-rod internal fixation and fusion with bone graft, of which 14 received atlas uniaxial screw internal fixation (uniaxial screw group) and 22 received atlas polyaxial screw internal fixation (polyaxial screw group). The operation time and intraoperative blood loss were compared between the two groups. The atlas fracture union rate and atlantoaxial posterior arch bone fusion rate were compared between the two groups at 3 months and 6 months after operation. The anterior atlantodental interval (ADI), basion-dens interval (BDI) and lateral mass displacement (LMD) were compared between the two groups to evaluate the reduction of fracture fragments before operation, at 1, 3, 6 months after operation and at the last follow-up. At the same time, the visual analogue scale (VAS) and neck dysfunction index (NDI) were compared between the two groups to evaluate neck pain and functional recovery. The postoperative complications were observed.Results:All patients were followed up for 12-44 months [(27.2±9.9)months]. There was no significant difference in operation time or intraoperative blood loss between the two groups (all P>0.05). The atlas fracture union rate and atlantoaxial posterior arch bone fusion rate were 85.7% (12/14) and 78.6% (11/14) in uniaxial screw group at 3 months after operation, insignificantly different from those in polyaxial screw group [72.7% (16/22) and 77.3% (17/22)] (all P>0.05). All patients in the two groups achieved bone union and fusion at 6 months after operation. There was no significant difference in ADI between the two groups before and after operation (all P>0.05). The BDI in the two groups did not differ significantly before operation ( P>0.05), but a significantly higher value was found in uniaxial screw group at 1, 3, and 6 months after operation and at the last follow-up [(5.9±1.3)mm, (5.8±1.3)mm, (5.9±1.2)mm and (5.8±1.2)mm] than in polyaxial screw group [(3.1±0.6)mm, (3.1±0.6)mm, (3.1±0.6)mm and (3.1±0.6)mm] (all P<0.01). The two groups did not differ significantly before operation ( P>0.05), but LMD at 1, 3, and 6 months after operation and at the last follow-up was (1.6±0.8)mm, (1.5±0.8)mm, (1.5±0.7)mm and (1.5±0.9)mm in uniaxial screw group, significantly lower than that in polyaxial screw group [(4.8±1.6)mm, (4.6±1.6)mm, (4.9±1.6)mm and (4.9±1.6)mm] (all P<0.01). There was no significant difference in VAS between the two groups before operation ( P>0.05). The VAS at 1, 3, and 6 months after operation and at the last follow-up was 3.0(3.0, 4.0)points, 2.0(1.0, 2.0)points, 1.0(0.8, 2.0)points and 1.0(0.0, 1.3)points in uniaxial screw group and was 3.5(3.0, 4.0)points, 2.0(2.0, 3.0)points, 2.0(1.0, 2.0)points and 2.0(1.0, 3.0)points in polyaxial screw group. In comparison, the VAS scored much lower in uniaxial screw group than in polyaxial screw group at 6 months after operation and at the last follow-up (all P<0.01). There was no significant difference in NDI between the two groups before operation ( P>0.05). The NDI at 1, 3, and 6 months after operation and at the last follow-up was 34.9±6.3, 23.4±6.2, 13.9±2.7 and 9.4±2.8 in uniaxial screw group and was 33.2±6.1, 24.4±6.3, 18.1±4.1 and 12.7±3.2 in polyaxial screw group, showing a significantly lower NDI in uniaxial screw group than in polyaxial screw group at 6 months after operation and at the last follow-up (all P<0.01). The complication rate was 21.4% (3/14) in uniaxial screw group when compared to 22.7% (5/22) in polyaxial screw group ( P>0.05). Conclusion:For Gehweiler type IIIb atlas fracture, both techniques can attain atlas fracture union and atlantoaxial posterior arch bone fusion, but the posterior atlas uniaxial screw instrumentation and fusion is superior in reduction of atlas fracture displacement and lateral mass separation, neck pain relief and functional improvement.

Cervical anterior approach atlantodentoplasty for the treatment of irreducible atlantoaxial dislocation complicated with bony abnormality of atlanto-dental joint / 中华骨科杂志

Objective:To evaluate the clinical efficacy of cervical anterior approach atlantodentoplasty for the treatment of irreducible atlantoaxial dislocation complicated with bony abnormality of atlanto-dental joint.Methods:Retrospective analysis was conducted to study the clinical data of 31 patients with irreducible atlantoaxial dislocation complicated with bony abnormality of atlanto-dental joint, including 7 males and 24 females; age ranged from 23 to 74 years, with an average of 49.0±12.0 years. All patients underwent cervical anterior approach soft tissue release, atlantodentoplasty and one-stage posterior occipito-cervical fixation and fusion. Twenty-one patients with atlantodental osteoarthritis underwent simplex atlantodental osteophyte resection, 5 patients with anterior tubercle hypertrophy of atlas and 5 patients with anterior tubercle hypertrophy of atlas and atlantodental osteoarthritis underwent atlantodental osteophyte resection and partial anterior tubercle resection. The operation time and blood loss of anterior procedure and total procedure were recorded. The anterior tubercle thickness (ATT), the atlantodental interval (ADI)were recorded before and 1 week after the operation. The available space of the cord (SAC), clivus-canal angle (CCA), cervicomedullaryangle (CMA), and the Japanese Orthopaedic Association (JOA) scores were recorded before the operation, 1 week, 3 months and 12 months after the operation, and at the last follow-up. The JOA improvement rate at the last follow-up was calculated, the time of postoperative bone graft fusion was recorded, and the complications were observed.Results:All patients were followed up for 12-60 months, with an average of 34.5±13.8 months. The operation time of anterior cervical atlantodentoplasty was 120.9±15.9 min, and the overall operation time was 315.1±31.4 min; The blood loss of anterior procedure was 101.2±31.2 ml, and that of overall procedure was 372.7±56.0 ml. The one week postoperative ATT (7.4±1.6 mm) of patients with anterior tubercle partial resection of atlas was lower than that before operation 10.8±1.5 mm ( t=4.94, P=0.001). The one week postoperative ADI 0.9±1.2 mm decreased compared with the preoperative ADI 8.3±2.2 mm ( t=17.91, P<0.001). The preoperative SAC was 10.4±2.8 mm, which increased to 19.2±3.6 mm one week after operation and 19.4±3.7 mm ( F=41.31, P<0.001) at last follow-up. The preoperative CCA was 119.4°±17.9°, which increased to 142.6°±13.0° one week after operation and 141.6°±12.2° ( F=35.86, P<0.001) at last follow-up. The preoperative CMA was 121.7°±14.1°, which increased to 148.9°±9.4° one week after operation and 149.4°±9.0° ( F=52.07, P<0.001) at last follow-up. The preoperative JOA score was 12.0±2.6, which was 14.3±1.3 one week after operation and 15.9±1.0 ( F=23.81, P<0.001) at last follow-up. JOA improvement rate was 78.9%±17.1%, while 23 cases were excellent (74.2%), 8 cases were good (25.8%), and the excellent and good rate was 100%; Thd fusion time of grafted bone was 5.7±1.5 months with the fusion rate of 100%; There were 12 patients with dysphagia after operation, all of which relieved spontaneously 5-10 days after operation; There were 3 cases of irritating choking after drinking or eating, and 2 cases were gradually alleviated 3-5 days after operation. One case was complicated with aspiration pneumonia due to stubborn choking, which gradually alleviated after 1 month of nasal feeding. No hardware failure or reduction loss, no serious complications such as esophageal injury, cerebrospinal fluid leakage, incision infection or vertebral artery injury occurred. Conclusion:Cervical anterior approach atlantodentoplasty for the treatment of irreducible atlantoaxial dislocation complicated with bony abnormality of atlanto-dental joint can anatomically reduce the atlantoaxial joint, and the clinical effect is satisfactory.

Clinical manifestations and management of infectious spondylitis following vertebroplasty or kyphoplasty / 中华创伤骨科杂志

Objective:To report the clinical manifestations and management of infectious spondylitis following vertebroplasty or kyphoplasty.Methods:Six cases of infectious spondylitis following vertebroplasty or kyphoplasty were analyzed retrospectively which had been treated at Department of Spinal Surgery, Henan Provincial People's Hospital between January 2014 and June 2019. They were 2 males and 4 females, aged from 64 to 81 years. Their visual analogue scale (VAS) scores ranged from 6 to 8 points; their spinal cord function was graded as C in 2 cases and E in 4 according to the American Spinal Cord Injury Association (ASIA) grading. All the patients were treated by sub-total resection of the infected vertebra, long segmental pedicle screw fixation and corresponding antibiotics therapy. The therapeutic efficacy was assessed by the inflammation indexes, imaging examinations and clinical manifestations.Results:The 6 patients were followed up for 12 to 42 months(mean 20.4 months). Their operation time ranged from 295 to 455 min (mean 370.8 min) and blood loss from 760 to 2, 250 mL (mean 1 536.7 mL). There were no such serious complications as dural tear, worsening of neurological symptoms or death. The last follow-up revealed normal body temperature and fine incision healing in all patients. Their inflammatory indexes returned to normal. Imaging examinations at the last follow-up showed no displacement of internal implants, no screw loosening or breakage of screws or rods, good bony fusion at the grafting site, and no inflammatory signals from the infected vertebra. At the last follow-up, their VAS for back pain ranged from 2 to 4 points, the ASIA grading was improved from C to D in 2 patients and maintained E in 4. Eventually, 4 patients recovered independent normal walking but 2 required a walker.Conclusions:Infectious spondylitis following vertebroplasty or kyphoplasty can lead to back pain and neurological dysfunction. Sub-total resection of the infected vertebra, long segmental pedicle screw fixation and corresponding antibiotics therapy can result in fine therapeutic outcomes.

Zoning laminectomy for the treatment of ossification of thoracic ligamentum flavum / 中华骨科杂志

Objective To investigate the safety and effect of zoning laminectomy for the ossification of thoracic ligamentum flavum.Methods From November 2011 to December 2014,34 patients (15 males,19 females;41-76 years old,average 55.0±8.1) with ossification of thoracic ligamentum flavum (OLF) were treated by zoning laminectomy.The course of disease ranged from 1 month to 123 months (average 16.5 months).According to the anatomical characteristics and the pathological ossification process of the thoracic ligamentum flavum,we proposed the concept of "zoning",which divided each segmental thoracic OLF into three zones:"safety zone","middle zone" and "risk zone".From the features of anatomy of LF and process of OLF development,we found there is no or less cerebrospinal fluid between spinal cord and the tip of each ossified nodular masses in severe OLF,any procedures using instruments in this area have the potential to cause irreversible spinal cord injury,we defined this area as "risk zone",the "null" area of each lamina and lateral and dorsal side of nodular masses as "safety zone",and the other area as "middle zone".From "safety zone" to "risk zone" the spinal canal decreased gradually,different zone needs different surgical strategy:This surgical procedure first removed the "null" area of superior and inferior lamina and dorsal side of each segmental OLF.Next,partially or totally resected the "middle zone",exploring the lateral side of nodular masses,and the "risk zone" was exposed and isolated.Finally,dissected the lateral side of nodular masses,and then the "risk zone" was floated and resected with a directly decompressing the spinal cord.Preoperative and postoperative modified Japanese Orthopedic Association (JOA) score and neurologic functional recovery ratio were used to evaluate the surgical outcomes.Results Of the total 83 decompressed OLF segments,5 (6.0％) located in the upper thoracic spine (T1-T4),8 (9.6％) in the midthoracic spine (T5-T8),and 70 (84.4％) in the lower thoracic spine (Tg-L 1).The followed up ranged from 4 to 40 months,with an average of 21.7±9.9 months.The mean JOA score increased significant from 5.3±2.0 preoperatively to 8.8±1.8 at the final follow-up (t=1 1.566,P=0.001).Postoperative average JOA neurologic functional recovery rates were 63.2％±24.7％,including excellent in 15 cases,good in 11 cases and fair in 8 cases.The excellent and good rate was 76.5％.Twelve cases had transient CSF leakage because of dural defect.The dural defect was only treated by tightly suturing the paraspinal muscles,the subcutaneous tissue,and the skin layers.The CSF leakage lasted for 6 to 8 days after operation.Two cases with wound infection were treated with debridement and antibiotics and healed completely.One case with thoracic spinal cord transient incomplete paralysis due to a post-operative epidural hematoma was treated with an emergency operation and got recovered neurological function.Conclusion Zoning laminectomy has the advantages of safe manipulation and thorough decompression,which is an effective choice for the surgical treatment of thoracic OLF.

Research of a novel tissue-engineered nerve graft for sciatic nerve repair in rats / 中华显微外科杂志

Objective To observe the effect of novel tissue engineered nerve grafts, which combined silk fi-broin/collagen scaffold with a co-culture of Schwann cells(SCs)and adipose-derived stem cells(ADSCs), to repair rat sciatic nerve defects. Methods From February, 2015 to August, 2016, the culture and purify SCs and ADSCs were isolated. And co-cultured at a ratio of 2∶1 and introduced into a silk fibroin (SF)/collagen scaffold to construct a tissue-engineered nerve conduit (TENC), which were transplanted to bridge 10 mm long sciatic nerve defects in rats. The experiment was divided randomly into 4 groups (10 rats/group): those bridged with plain SF/collagen scaffolds (Scaffold group), those bridged with TENCs (TENC group), those bridged with autografts (Autograft group) and those unoperated side (Normal group). The mechanical properties were examined using a universal testing machine(Instron 5865). Scanning electron microscopy was performed to observe the structure of the SF/collagen scaffold and the cells' growth. A series of electrophysiological examinations and morphological analyses were performed 12 weeks after surgery to evaluate the effect of the TENC on peripheral nerve regeneration.And One-way ANOVA was used to ana-lyze the data. If the differences between groups were statistically significant, the Turkey's method was further applied for comparison. Results The plain SF/collagen scaffold showed appropriate pore size and good intercommunicating of holes. The cells were tightly attached to and partly coiled about the scaffold and exhibited either a spindle or a spherical shape. The results of the mechanical measurement revealed that the maximum and average Young’s moduli of the SF/collagen scaffold were (10.80 ± 0.30) MPa and (8.14 ± 0.20) MPa, respectively. The mechanical properties ensure that the scaffold could resist muscular contraction and maintain its shape unchanged for a considerable period of time after grafting.All rats in each group had achieved nerve defect regeneration in varying degrees.But in terms of the effect of the repaired nerve, those treated with TENC were similar to those with autologous nerve grafts but superior to those with plain SF/collagen scaffolds. Conclusion The TENC that combined silk fibroin/collagen scaffold with a co-culture of SCs and ADSCs had normal nerve-like structure, and can bridge sciatic nerve defect and promote nerve growth.

Transpedicular screw placement in the cervical vertebrae assisted by rapid prototyping individual navigation template / 中国组织工程研究

BACKGROUND:The cervical pedicle screws provide ideal three-column stability for cervical vertebra, but there is stil no a standard with the choice of pedicle screw place methods in cervical vertebra. Here, we try to seek a simpler, safer and accurate pedicle screw place method.OBJECTIVE:To evaluate the accuracy and security of transpedicular screw placement assisted by rapid prototyping individual navigation template. METHODS:Eight cadaver cervical specimens (C3-6) were selected to take CT-scan and data were saved in DICOM format. Three-dimensional (3D) software MIMICS was used to establish the C3~6 3D model, and designed the best pedicle screw channel. According to the morphological feature of the posterior cervical spine elements, the reverse template was designed. Then, the best pedicle screw channels were fused into bilateral navigation template. The navigation template was manufactured by rapid prototyping, and saved in STL format. Rapid prototyping technology was used to print out the navigation template. Cervical pedicle screws were inserted with the assistance of navigation templates fitted with the posterior structure of the vertebral body. Postoperative X-ray and CT scan were used to evaluate the accuracy of screw placement. RESULTS AND CONCLUSION:(1) Total y 64 screws were inserted with the assistance of individual navigation templates. Of them, 62 screws were completely in the pedicle;1 screw perforated the medial cortex of pedicle;1 screw perforated the lateral cortex of pedicle. Accuracy of screw placement was 97%. (2) The individual navigation template with a high accuracy rate is a feasible and safe method for cervical pedicle screw placement, which has great prospects for clinical application.