The association of cervical sagittal alignment with anterior bone loss following single-level anterior cervical surgery.

Background: Anterior bone loss (ABL) is a common phenomenon after cervical disc replacement (CDR), which can also be observed after anterior cervical discectomy and fusion (ACDF). This study aimed to investigate the incidence and severity of ABL in single-level CDR and ACDF and explore the association of cervical sagittal alignment with ABL. Methods: This is a single-center retrospective cohort study. A total of 113 patients treated with CDR and 99 patients treated with ACDF were retrospectively reviewed from January 2014 to December 2018 in West China Hospital. Radiological data were collected at pre-operation, 1 week, 3 months postoperatively, and the last follow-up. The incidence and severity of ABL after both CDR and ACDF were evaluated. Cervical sagittal alignment parameters, including C0-C2 angle, cervical lordosis (CL), C2-C7 sagittal vertical axis (cSVA), T1 slope, functional spinal unit angle, disc angle, and surgical level slope, were evaluated. Results: ABL was identified in 75 (66.4%) patients in the CDR group and 57 (57.6%) patients in the ACDF group. There were no significant differences in the incidence, severity, and location of ABL between the ACDF and CDR groups. For patients who underwent ACDF, the proportion of females was significantly higher in the ABL group (64.9% vs. 33.3%, P=0.002), whereas the body mass index (BMI) was significantly lower in the ABL group compared to the non-ABL group (22.72±3.09 vs. 24.60±3.04, P=0.002). No effect of ABL on the short-term clinical outcomes of ACDF and CDR was observed. In the ACDF group, patients with ABL had significantly smaller postoperative CL (11.83°±8.24° vs. 15.25°±8.32°, P=0.04) and cSVA (17.77±10.08 vs. 23.35±9.86 mm, P=0.007). In the CDR group, no significant differences were found in the cervical sagittal parameters between patients with and without ABL (CL: 12.58±8.70 vs. 15.46±8.50, P=0.10; cSVA: 20.95±8.54 vs. 19.40±9.43, P=0.38). Conclusions: ABL is common after both CDR and ACDF with comparable incidence and severity. Cervical sagittal alignment was closely related to ABL after ACDF yet had less influence on ABL after CDR.

Health-related Quality of Life (HRQOL) Outcomes of Selective/Nonselective Thoracic Fusion for Lenke 1C Adolescent Idiopathic Scoliosis (AIS) Patients with a Minimum 4-year Follow-up.

OBJECTIVE: Both the selective thoracic fusion (STF) and nonselective thoracic fusion (NSTF) are treatments for Lenke 1C adolescent idiopathic scoliosis (AIS). To date, the impacts of the two surgical strategies on patients' long-term quality of life remain unclear. Therefore, the purpose of this study was to explore the long-term effects of STF/NSTF on the quality of life in Lenke 1C AIS patients through a 4-10-year follow-up. METHODS: From January 2011 to April 2018, according to the inclusion and exclusion criteria, a retrospective single-center study of 75 surgical patients with Lenke 1C curves was performed (n = 75). They all underwent posterior fusion, and patients were divided into the selective thoracic fusion (STF) group (n = 42) and the nonselective thoracic fusion (NSTF) group (n = 33) based on their surgical approach. All participants received the survey of the visual analogue scale (VAS), SRS30, SF12, and Oswestry disability index (ODI) scales. Patients' gender, age, body mass index (BMI), surgical approach (STF/NSTF), surgical segments (UIV and LIV), follow-up time, complications, preoperative, postoperative, and last follow-up Cobb angles, and health-related quality of life (HRQOL) outcomes were collected, and analyzed through the Shapiro-Wilks test, Wilcoxon rank-sum test, t-test, and χ2 test. RESULTS: The mean follow-up of the entire cohort was 73 ± 5.6 months. The lumbar Cobb angle in the STF group improved from 31.8 ± 6.5° to 11.5 ± 5.1° after the operation and 10.3 ± 6.9° at the last follow-up. The postoperative correction rate of the lumbar curve was 63.8%, which increased to 67.7% at the last follow-up. In the NSTF group, the lumbar Cobb angle improved from 34.3 ± 11.3° to 4.3 ± 3.7° after the operation, and was 5.1 ± 3.1° at the last follow-up. The postoperative correction rate of the lumbar curve was 87.4%, and 85.1% at the last follow-up. At the last follow-up, the STF group had higher overall HRQOL scores than the NSTF group, and there were statistically differences between the different groups (STF/NSTF) in SRS-30-Mental health (p = 0.03), SRS-30-Satisfaction with management (p = 0.02), SRS-30-Pain (p = 0.03), ODI (p = 0.01), SF-12 PCS (p = 0.03), VAS back pain (p = 0.005) and VAS leg pain (p = 0.001). No statistically differences were found in SF12 MCS, SRS-30-Self-image/Appearance and SRS-30 Function/activity. CONCLUSION: After 4-10 years of follow-up, we found that the STF group achieved satisfactory correction results, and compared with the NSTF group, their overall HRQOL scores were higher, especially in terms of pain and satisfaction, where the STF group shows a significant advantage.

Biomechanical performance of the novel assembled uncovertebral joint fusion cage in single-level anterior cervical discectomy and fusion: A finite element analysis.

Introduction: Anterior cervical discectomy and fusion (ACDF) is widely accepted as the gold standard surgical procedure for treating cervical radiculopathy and myelopathy. However, there is concern about the low fusion rate in the early period after ACDF surgery using the Zero-P fusion cage. We creatively designed an assembled uncoupled joint fusion device to improve the fusion rate and solve the implantation difficulties. This study aimed to assess the biomechanical performance of the assembled uncovertebral joint fusion cage in single-level ACDF and compare it with the Zero-P device. Methods: A three-dimensional finite element (FE) of a healthy cervical spine (C2-C7) was constructed and validated. In the one-level surgery model, either an assembled uncovertebral joint fusion cage or a zero-profile device was implanted at the C5-C6 segment of the model. A pure moment of 1.0 Nm combined with a follower load of 75 N was imposed at C2 to determine flexion, extension, lateral bending, and axial rotation. The segmental range of motion (ROM), facet contact force (FCF), maximum intradiscal pressure (IDP), and screw-bone stress were determined and compared with those of the zero-profile device. Results: The results showed that the ROMs of the fused levels in both models were nearly zero, while the motions of the unfused segments were unevenly increased. The FCF at adjacent segments in the assembled uncovertebral joint fusion cage group was less than that that of the Zero-P group. The IDP at the adjacent segments and screw-bone stress were slightly higher in the assembled uncovertebral joint fusion cage group than in those of the Zero-P group. Stress on the cage was mainly concentrated on both sides of the wings, reaching 13.4-20.4 Mpa in the assembled uncovertebral joint fusion cage group. Conclusion: The assembled uncovertebral joint fusion cage provided strong immobilization, similar to the Zero-P device. When compared with the Zero-P group, the assembled uncovertebral joint fusion cage achieved similar resultant values regarding FCF, IDP, and screw-bone stress. Moreover, the assembled uncovertebral joint fusion cage effectively achieved early bone formation and fusion, probably due to proper stress distributions in the wings of both sides.

Effect of perioperative steroids application on dysphagia, fusion rate, and visual analogue scale (VAS) following anterior cervical spine surgery: A meta-analysis of 14 randomized controlled trials (RCTs).

Objective: To conduct a high-level meta-analysis of the RCTs to evaluate perioperative steroids use in the management of fusion rate, dysphagia, and VAS following anterior cervical spine surgery for up to 1 year. Methods: We searched the database PubMed, EMBASE, Web of Science, Cochrane Library, Google Scholar, Ovid, and ClinicalTrials.gov without time restriction to identify RCTs that evaluate the effectiveness of perioperative steroids after anterior cervical spine surgery. A subgroup analysis was undertaken to investigate the effects of intravenous and local steroids. This study was registered in the PROSPERO database prior to initiation (CRD42022313444). Results: A total of 14 RCTs were eligible for final inclusion. This meta-analysis showed that steroids could achieve lower dysphagia rate (p < 0.001), severe dysphagia rate within 1 year (p < 0.001), lower VAS scores at both 1 day (p = 0.005), 2 weeks (p < 0.001) and shorter hospital stay (p = 0.014). However, there was no significant difference between the two groups regarding operation time (p = 0.670), fusion rates (p = 0.678), VAS scores at 6 months (p = 0.104) and 1 year (p = 0.062). There was no significant difference between intravenous and local steroid administration regarding dysphagia rates (p = 0.82), fusion rate (p = 1.00), and operative time (p = 0.10). Conclusion: Steroids intravenously or locally following anterior cervical spine surgery can reduce incidence and severity of dysphagia within 1 year, VAS score within 2 weeks, and shorten the length of hospital stay without affecting fusion rates, increasing the operating time, VAS score at 6 months and 1 year.

Biomechanical Effects of a Novel Anatomic Titanium Mesh Cage for Single-Level Anterior Cervical Corpectomy and Fusion: A Finite Element Analysis.

Background: The traditional titanium mesh cage (TTMC) has become common as a classical instrument for Anterior Cervical Corpectomy and Fusion (ACCF), but a series of complications such as cage subsidence, adjacent segment degeneration (ASD), and implant-related complications by using the TTMC have often been reported in the previous literature. The aim of this study was to assess whether a novel anatomic titanium mesh cage (NTMC) could improve the biomechanical condition after surgery. Methods: The NTMC model consists of two spacers located on both sides of the TTMC which match the anatomic structure between the endplates by measuring patient preoperative cervical computed tomography (CT) data. The ranges of motion (ROMs) of the surgical segments and the stress peaks in the C6 superior endplates, titanium mesh cage (TMC), screw-bone interface, anterior titanium plate, and adjacent intervertebral disc were compared. Results: Compared with the TTMC, the NTMC reduced the surgical segmental ROMs by 89.4% postoperatively. The C6 superior endplate stress peaks were higher in the TTMC (4.473-23.890 MPa), followed by the NTMC (1.923-5.035 MPa). The stress peaks on the TMC were higher in the TTMC (47.896-349.525 MPa), and the stress peaks on the TMC were lower in the NTMC (17.907-92.799 MPa). TTMC induced higher stress peaks in the screw-bone interface (40.0-153.2 MPa), followed by the NTMC (14.8-67.8 MPa). About the stress peaks on the anterior titanium plate, the stress of TTMC is from 16.499 to 58.432 MPa, and that of the NTMC is from 12.456 to 34.607 MPa. Moreover, the TTMC induced higher stress peaks in the C3/4 and C6/7 intervertebral disc (0.201-6.691 MPa and 0.248-4.735 MPa, respectively), followed by the NTMC (0.227-3.690 MPa and 0.174-3.521 MPa, respectively). Conclusion: First, the application of the NTMC can effectively decrease the risks of TMC subsidence after surgery. Second, in the NTMC, the stresses at the anterior screw-plate, bone-screw, and TMC interface are much less than in the TTMC, which decreased the risks of instrument-related complications after surgery. Finally, increases in IDP at adjacent levels are associated with the internal stresses of adjacent discs which may lead to ASD; therefore, the NTMC can effectively decrease the risks of ASD.

Biomechanical Evaluation of Intervertebral Fusion Process After Anterior Cervical Discectomy and Fusion: A Finite Element Study.

Introduction: Anterior cervical discectomy and fusion (ACDF) is a widely accepted surgical procedure in the treatment of cervical radiculopathy and myelopathy. A solid interbody fusion is of critical significance in achieving satisfactory outcomes after ACDF. However, the current radiographic techniques to determine the degree of fusion are inaccurate and radiative. Several animal experiments suggested that the mechanical load on the spinal instrumentation could reflect the fusion process and evaluated the stability of implant. This study aims to investigate the biomechanical changes during the fusion process and explore the feasibility of reflecting the fusion status after ACDF through the load changes borne by the interbody fusion cage. Methods: The computed tomography (CT) scans preoperatively, immediately after surgery, at 3 months, and 6 months follow-up of patients who underwent ACDF at C5/6 were used to construct the C2-C7 finite element (FE) models representing different courses of fusion stages. A 75-N follower load with 1.0-Nm moments was applied to the top of C2 vertebra in the models to simulate flexion, extension, lateral bending, and axial rotation with the C7 vertebra fixed. The Von Mises stress at the surfaces of instrumentation and the adjacent intervertebral disc and force at the facet joints were analyzed. Results: The facet contact force at C5/6 suggested a significantly stepwise reduction as the fusion proceeded while the intradiscal pressure and facet contact force of adjacent levels changed slightly. The stress on the surfaces of titanium plate and screws significantly decreased at 3 and 6 months follow-up. A markedly changed stress distribution in extension among three models was noted in different fusion stages. After solid fusion is achieved, the stress was more uniformly distributed interbody fusion in all loading conditions. Conclusions: Through a follow-up study of 6 months, the stress on the surfaces of cervical instrumentation remarkably decreased in all loading conditions. After solid intervertebral fusion formed, the stress distributions on the surfaces of interbody cage and screws were more uniform. The stress distribution in extension altered significantly in different fusion status. Future studies are needed to develop the interbody fusion device with wireless sensors to achieve longitudinal real-time monitoring of the stress distribution during the course of fusion.

Comparison of Effect of Navigation Versus No Navigation on Vertebral Body Screw Placement in Anterior Approach Surgery for Thoracolumbar Burst Fractures: A Randomized Controlled Trial.

OBJECTIVE: We evaluated the effects of using a navigation technique with anterior approach surgery for thoracolumbar burst fractures on vertebral body screw placement and discussed its effects on the long-term prognosis of patients. METHODS: We performed a prospective study of patients who had undergone anterior approach thoracolumbar surgery from May 2018 to August 2019. The 40 patients were randomly divided into the navigation group (NG) and control group (CG). In the NG, vertebral body screw placement was performed with 2-dimensional navigation guidance. For the CG, no navigation guidance was used. The clinical and radiological evaluations of the 2 groups were compared preoperatively, immediately after surgery, and at the final follow-up. Paired t tests and the χ2 test were used to evaluate the clinical and radiological indicators. RESULTS: No differences were found in the hospital stay, operation time, autologous blood recovery, postoperative drainage volume, Cobb angle of the preoperative coronal plane and sagittal plane, postoperative sagittal plane, postoperative Cobb angle of the coronal and sagittal planes measured on radiographs and computed tomography scans between the 2 groups (P > 0.05). The correction of the kyphosis deformity of the fracture segment was better in both groups (P < 0.001). The intraoperative blood loss and Cobb angle of the postoperative coronal plane in the NG was less than that in the CG (P < 0.05). Also, the 4 vertebral body screws in the NG were more parallel to the endplate than were those in the CG. CONCLUSIONS: We found that the use of navigation can improve the accuracy of screw placement in anterior approach surgery for thoracolumbar burst fractures and improve patients' long-term prognosis.

[Applied anatomy research of the uncovertebral joint for design of uncovertebral joint fusion cage].

OBJECTIVE: To measure anatomical parameters related to cervical uncovertebral joint and provide data support for the design of uncovertebral joint fusion cage. METHODS: According to the inclusion and exclusion criteria, raw DICOM data of cervical CT scan in 60 patients (30 males and 30 females, aged 39-60 years) were obtained, then the three-dimensional cervical spine model was reconstructed for anatomical measurement by using the Mimics19.0 software. The height of the uncinate process, the length of the uncinate process, the width of the uncinate process, and the length of the uncovertebral joint in the intervertebral foramen region were measured bilaterally from C3 to C7. The anterior and posterior distances between the uncinate processes were measured from C3 to C7. The height of the uncovertebral joint space, the central height of the intervertebral disc space, and the depth of the intervertebral disc space were also measured from C2, 3 to C6, 7. The mean, standard deviation, maximum, and minimum were calculated by using the SPSS22.0 statistical software for the design of uncovertebral joint fusion cage. RESULTS: The height of the uncinate process, the length of the uncinate process, the width of the uncinate process, and the length of the uncovertebral joint in the intervertebral foramen region of C3-C7 and the height of the uncovertebral joint space of C2, 3-C6, 7 showed no significant difference between two sides (P>0.05). The height of the uncovertebral joint space also had no significant difference between females and males (P>0.05). The anterior distances between the uncinate processes of C3-C7 were significantly larger than the posterior distances between the uncinate processes (P<0.05), the uncovertebral joint presented a posterior cohesive shape. The central height of the intervertebral disc space in male group was slightly higher than that in female group, and the differences were significant (P<0.05) at C2, 3 and C5, 6; the depth of the intervertebral disc space in male group was significantly higher than that in female group (P<0.05). The central height of the intervertebral disc space was (4.94±0.49) mm (range, 3.81-5.90 mm), the depth of the intervertebral disc space was (15.78±1.23) mm (range, 12.94-18.85 mm), the anterior and posterior distances between the uncinate processes were (17.19±2.39) mm (range, 13.39-24.63 mm) and (10.84±2.12) mm (range, 7.19-16.64 mm), respectively. According to the results of the anatomical research, the height of the uncovertebral joint fusion cage was designed as 5, 6, 7, and 8 mm; the depth of the uncovertebral joint fusion cage was designed as 12, 13, 14, 15, and 16 mm; the width of the uncovertebral joint fusion cage was designed as 14-18 mm; and the two wings are designed as arc-shape with 2 and 3 mm in width. CONCLUSION: There are certain differences in the anatomical parameters of the uncovertebral joint between different segments. The uncovertebral joint fusion cage that designed based on the results of anatomical research is suitable for most patients.

Comparison the efficacy of hemorrhage control of Surgiflo Haemostatic Matrix and absorbable gelatin sponge in posterior lumbar surgery: A randomized controlled study.

OBJECTIVE: To compare the hemostatic effect of hematostatic agent Surgiflo and absorbable gelatin sponge (AGS) in posterior lumbar surgery. METHODS: A total of 60 cases were recruited during August 2016 and June 2017 according to the inclusion and exclusion criteria. Patients were randomly allocated to the Surgiflo Haemostatic Matrix (SHM) group or the AGS group (AGS) by computer-generated randomization codes. The success rates of hemostasis for 3 minutes and 5 minutes, the time of operation, the amount of intraoperative bleeding, the volume of autogenously blood transfusion, the amount of blood during hemostasis, the amount of blood transfusion, and BP, RBC, HCT, HB of preoperative, 2 to 3 days, and 5 to 7 days following operation were recorded to compare. Daily drainage and all adverse events after operation were also compared. RESULTS: All the patients were followed up for at least 1 month. The RBC and HCT of the AGS group before operation were lower than those in the control group (P = .039, P = .029), but there was no difference after operation (P >.05). In the control group, 19 cases were successfully hemostatic in 3 minutes, 4 cases were successful in 5 minutes, and 7 cases were combined with hemostasis. In the SHM group, it was 22, 3, and 5 cases respectively. There was significant difference in blood loss during hemostatic process between the 2 groups (P <.001). There was no difference in the amount of blood loss and autologous blood transfusion between the 2 groups, and there was no difference in the operation time between the 2 groups. In the AGS group, allogeneic blood was infused in 1 case during operation, and no allogeneic blood was infused in the other patients. The drainage volume on the 1st day and the 2nd to 4th day after operation in the AGS group was less than that in the control group (P = .015, P = .010). CONCLUSION: Compared with AGS, SHM could decrease the blood loss during hemostatic process and the postoperative drainage volume in posterior operation of lumbar degenerative disease. SHM is a safe and effective hemostatic agent in lumbar posterior surgery.

Incidence of dysphagia and dysphonia after Hangman's fractures: Evidence from 93 patients.

This research aims to explore the accurate incidence, severity and outcomes of dysphagia and dysphonia after Hangman fractures.A total of 93 patients were included in this study and clinical data were reviewed. The Bazaz grading system (0-None; 1-Mild; 2-Moderate; 3-Severe) was used for dysphagia evaluation and the Voice Handicap Index-10 used to evaluate dysphonia. In all of the patients, evaluation of dysphagia and dysphonia was performed preoperatively and at 1 week, 1 month, 3, 6, and 12 months after surgery. SPSS 22.0 software (SPSS Inc, Chicago, IL) was used for all statistical analyses.Posttraumatic immediate dysphagia was found in 8 patients and posttraumatic immediate dysphonia was observed in 3 patients. The incidence of dysphagia was 22.6% at the 1st week, 16.1% at the 1st month, and 9.7% at the 3rd month of follow-up. The incidence of dysphonia was 24.5% at the 1st week, 11.3% at the 1st month, and 3.8% at the 3rd month of follow-up.Posttraumatic immediate dysphagia and dysphonia occurred and the anterior surgical approach was associated with a higher incidence of dysphagia compared to posterior surgery and nonoperative patients. Most dysphagia and dysphonia were mild and gradually decreased during the subsequent 3 months after surgery. Future prospective, randomized studies with larger sample sizes are required to validate these data.

[Modified incision to prevent the postoperative spinal lateral angulation in surgery via anterior approach for lumbar fracture].

OBJECTIVE: To explore a method of modified incision to prevent the postoperative spinal lateral angulation via anterior approach for lumbar fracture. METHODS: A total 40 patients with lumbar fracture from January 2016 to Jun 2017 were internalized in the study. Including 28 males and 12 females, aged from 27 to 68 years with an average of (39.5±14.9) years. Among them, 28 cases caused by high fall, 9 cases by heavy injury, 3 cases by traffic accidents; and 35 fractures were located at L1,4 at L2,1 at L3. All the fractures were type A based on AO classification. According to Frankel classify of spinal cord injury, 5 cases were grade A, 1 case was B, 10 cases were C, 15 cases were D, 9 cases were E. The patients were divided randomly into modified incision groups and routine incision groups. All patients were treated with decompression, internal fixation and titanium mesh supported bone graft fusion via anterior approach. All the internal fixation materials were ANTERIOR (Medtronic Inc). Incision direction and incision plane were improved in modified incision groups. The coronal Cobb angle and the angle between the vertebral screw and the corresponding endplate were analyzed before and after operation. RESULTS: Pre-and post-operative coronal Cobb angles were (1.20±3.26) °, ( 2.16±3.55)° in modified incision groups and(1.22±4.42)°, (3.91±3.78)° in routine incision groups respectively. And there was no statistical difference before operation, and there was statistical difference after operation between two groups(P=0.017). There was no lateral angulation of more than 5 degrees in modified incision group, but there was lateral angulation of 5 to 10 degrees in routine incision group in 6 cases. The incidence of lateral angulation about 5 degrees after operation was significantly different between two groups (P=0.010). There was significant difference in the angle between the proximal two vertebral screws and the corresponding endplate between two groups (P<0.05), but there was no significant difference in the angle between the distal two vertebral screws and the corresponding endplate (P>0.05). CONCLUSIONS: The improvement of incision direction and plane can effectively prevent the postoperative spinal lateral angulation via anterior approach for lumbar fracture.

Anterior release and nonstructural bone grafting and posterior fixation for old lower cervical dislocations with locked facets.

Lower cervical dislocations are often missed at the time of initial injury for several reasons. The treatment of old facet dislocations of the lower cervical spine is difficult, and the optimal method has not been established. The objective of the present study was to evaluate the clinical outcomes of a surgical technique, anterior release, and nonstructural bone grafting combined with posterior fixation, for the treatment of old lower cervical dislocations with locked facets.This was a retrospective study of 17 patients (13 men and 4 women) with old facet dislocations, who underwent the same surgical treatment at our hospital between April 2010 and January 2016. The anterior procedure was conducted to remove the fusion mass and to achieve discectomy and morselized bone grafting. Subsequent posterior procedure included release, reduction, and posterior fusion. The neurologic status, clinical data (Japanese Orthopedic Association [JOA], Neck Disability Index [NDI], and Visual Analog Scale [VAS] scores), and radiographic information (local sagittal alignment and bone graft fusion) were recorded and evaluated pre and postoperatively.All patients achieved a nearly complete reduction intraoperatively. The mean operative time was 178 ±â€Š49 minutes. The mean blood loss was 174 ±â€Š73 mL. Each patient completed at least 12 months of follow-up. The mean follow-up duration was 32.6 ±â€Š18.5 months. The neurologic status according to the Frankel grade was significantly improved at the last follow-up. The JOA, NDI, and VAS scores all demonstrated significant improvements compared with the preoperative values (P < .05). The kyphosis angle of the dislocated segments was 10.5 ±â€Š5.9° at preoperation, and was corrected to 5.9 ±â€Š4.3° lordosis postoperatively. Anterior and posterior solid fusion was observed in all patients within 12 months of follow-up. Fat liquefaction and delayed healing of the posterior wound occurred in 1 patient. Cerebrospinal fluid leakage occurred in another patient. There was no neurologic deterioration and no procedure-related complications.Anterior release and nonstructural bone grafting combined with posterior fixation provides a safe and effective option for treating old lower cervical dislocations with locked facets.

Biomechanical Analysis of Bilateral Facet Joint Stabilization Using Bioderived Tendon for Posterior Cervical Spine Motion Reservation in Goats.

OBJECTIVES: To investigate the biomechanical properties of a novel stabilization method for posterior cervical motion preservation using bioderived freeze-dried tendon. METHODS: Experiments were conducted both in vitro and in vivo. For the in vitro group, 15 fresh-frozen goat spines (C1-C7) were randomly divided into 3 subgroups: intact (INT-vitro, n = 5), injury model (IM-vitro, n = 5), and bilateral facet joint stabilization (BFJS-vitro, n = 5) subgroups. For the in vivo group, 15 adult goats were randomly divided into 3 experimental subgroups: INT-vivo subgroup (n = 5), IM-vivo subgroup (n = 5), and BFJS-vivo subgroup (n = 5). Goats in the in vivo group were euthanized 12 weeks after surgery. Biomechanical tests were performed to evaluate range of motion. Histologic analysis was conducted to evaluate survival and reactions associated with the bioderived tendon. RESULTS: Compared with the INT-vitro and INT-vivo subgroups, the flexion of IM-vitro and IM-vivo subgroups increased significantly, respectively (P < 0.05). The flexion of the BFJS-vitro and BFJS-vivo subgroups was significantly smaller than in the IM-vitro and IM-vivo subgroups, respectively (P < 0.05). Significant differences between the BFJS-vitro and BFJS-vivo subgroups were observed in flexion, lateral bending, and rotation (P < 0.05). Histologic evaluation demonstrated that fibers arranged regularly and stained homogeneously. New vessels in growth indicated that the bioderived tendon was survival and processed good regeneration. CONCLUSIONS: Bilateral facet joint stabilization can significantly limit excessive flexion motion and maintain adequate stability. Furthermore, the preservation of extension motions without limiting lateral bending and rotation ideally simulates the features of the posterior ligamentous complex. This preserves the dynamic stability of the lower cervical spine.

Pulled-out locking screw re-screwed spontaneously in anterior cervical decompression and fusion with the zero-profile implant system: A case report.

RATIONALE: The zero-profile, standalone device (Zero-P, Synthes GmbH, Switzerland) has been reported to be an effective and safe treatment method with similar clinical outcomes compared with plate. Instrumental complications concerning Zero-P have been little reported. Considering the rarity, we present this amazing case to share with our spinal surgeons and instrument specialists. PATIENT CONCERNS: A 46-year-old man patient presented to our hospital with neck and shoulders pain for 23 years, numbness and weak-ness of right hand for 6 months. DIAGNOSES: Hypoesthesia in the right C6 and C7 roots distribution, myodynamia weakness of the right little finger was detected from physical examination. Two-level anterior cervical decompression and fusion (ACDF) using the Zero-P was performed via a classic right Smith-Robinson approach after induction of general anesthesia. Three months postoperative x-rays showed a good position of the implant. Six months postoperative x-rays showed a locking screw at the segment C6/7 pulled out. The patient was diagnosed as screw pullout after ACDF. INTERVENTIONS: The patient was treated conservatively with regular follow-up as he was asymptomatic and no evidence of esophageal perforation was detected. OUTCOMES: The patient was followed again and 24 months postoperative x-rays also showed the pulled-out locking screw had re-screwed spontaneously. The patient was noticed that a revision surgery was needed if symptoms occur. At present bony union is not reached but he is still asymptomatic. LESSONS: Pulled-out screws re-screwed spontaneously are rare but it does occur. Insertion angle may affect the stability of the Zero-P device, and the repeated micro-motion may be the critical reason of the screw pull-out and re-screwing. The management of screws pull-out after ACDF remains individualized and a revision surgery is not necessary for every patient. Conservative treatment such as orthosis and regular follow-ups may be suitable for some asymptomatic patients.

Primary leiomyosarcoma of the spine: A case report and literature review.

RATIONALE: Primary leiomyosarcoma of the bone was firstly reported by Evans and Sanerkin in 1965, whereas primary leiomyosarcoma of the vertebra is extremely rare. Because of the rarity of primary vertebral leiomyosarcoma, the diagnosis, treatment, and clinical outcome still remain controversial. Here we report a special case of primary leiomyosarcoma in the thoracic vertebra. PATIENT CONCERNS: A 47-year-old female patient was admitted to our institution with the chief complaint of persistent back pain for 4 weeks. She had no symptoms of numbness, weakness, pain, and abnormal sensation in her extremities. DIAGNOSES: Neurological examination on admission revealed no obvious abnormality. Magnetic resonance imaging showed a bone destruction of the T11 vertebral body and the right pedicle. Therefore, primary vertebral leiomyosarcoma was suspected. Pathological hematoxylin and eosin staining of the resected tumor revealed a diagnosis of polymorphic undifferentiated sarcoma. Furthermore, to identify the subtype of this sarcoma, the immunohistochemical staining of the tumor was performed with each of the various antibodies and the results are epithelial membrane antigen (-), H-caldesmon (-), desmin (+), smooth muscle actin (+), S-100 (-), myogenin (-), pan-keratin (-), and Ki-67 (positive rate: 20%). Finally, the patient was diagnosed as primary vertebral leiomyosarcoma. INTERVENTIONS: the anterior corpectomy and autogenous iliac bone graft with instrumentation combined with the posterior spinal canal decompression and fusion with the pedicle screw system were performed through an anterior-posterior union approach. OUTCOMES: Neither clinical symptoms nor signs of tumor recurrence were detected within the follow-up of 6 months. In addition, 11 cases of the primary vertebral leiomyosarcoma reported in the literature were reviewed and summarized. LESSONS: Exclusion of metastatic leiomyosarcoma by various imaging modalities and histopathological examinations, especially the immunohistochemical staining with various antibodies against the epithelial and mesenchymal cell markers, are critical for establishing the correct diagnosis of the primary vertebral leiomyosarcoma. Surgical resection, especially the total en bloc spondylectomy, is the main treatment option with a good outcome, albeit with a limited follow-up duration.

[Early effectiveness of cervical disc replacement by using Pretic-I].

Objective: To observe the early effectiveness of cervical disc replacement with Pretic-I, a new type artificial disc. Methods: A retrospective analysis was made on the clinical data of 10 patients who underwent single segmental cervical disc replacement with Pretic-I from June to December 2014. Among 10 patients, 4 were male and 6 were female, with an average age of 40 years (range, 27-51 years). The mean disease duration was 15.4 months (range, 4-36 months). Affected segments located at C 4, 5 level in 1 case, at C 5, 6 level in 8 cases, and at C 6, 7 level in 1 case. The visual analogue scale (VAS), Japanese Orthopaedic Association (JOA) score, and neck disability index (NDI) were used to evaluate the clinical outcomes. Besides, the disc height and the range of motion (ROM) at operated level, and ROM of upper and lower adjacent level were measured to assess the function. Results: The operation was successfully completed in all patients who were followed up for 12 months. No complications of aggravated nerve symptoms, vertebral artery injury, esophagotracheal fistula, cerebrospinal fluid leakage, incision infection, hematoma and prosthetic loosening were observed during follow-up. The VAS score, JOA score, and NDI significantly improved at each time point after operation when compared with preoperative scores ( P<0.05). The height of intervertebral disc at operated level was significantly increased at immediate and 3 months after operation when compared with preoperative one ( P<0.05), but no significant difference was found between at 6 months or 12 months after operation and at pre-operation ( P>0.05). No significant difference was shown in the ROM at operated level, and ROM of upper and lower adjacent level between at pre-operation and at each time point after operation ( P>0.05). Conclusion: The early effctiveness of cervical disc replacement using Pretic-I is satisfactory. The symptoms can be relieved significantly and the dynamic features of the operated level, as well as the upper and lower adjacent levels, are well preserved.

Comparison of the incidence of patient-reported post-operative dysphagia between ACDF with a traditional anterior plate and artificial cervical disc replacement.

PURPOSE: Compared with anterior cervical discectomy and fusion (ACDF), cervical disc replacement (CDR) has provided satisfactory clinical results. The incidence of post-operative dysphagia between ACDF with a traditional anterior plate and CDR remains controversial. Considering the limited studies and knowledge in this area, a retrospective study focusing on post-operative dysphagia was conducted. METHODS: The Bazaz grading system was used to assess the severity of dysphagia at post-operative intervals including 1 week, 1 month, 3 months, 6 months, 12 months and 24 months respectively. The Chi-square test, Student t-test, Mann-Whitney U tests and Ordinal Logistic regression were used for data analysis when appropriate. Statistical significance was accepted at a probability value of <0.05. RESULTS: Two hundred and thirty-one patients in the CDR group and one hundred and fifty-eight patients in Plate group were included in this study. The total incidences of dysphagia in the CDR and plate group were 36.58% and 60.43% at one week, 29.27% and 38.85% at one month, 21.95% and 31.65% at three months, 6.83% and 17.99% at six months, 5.85% and 14.39% at 12 months, and 4.39% and 10.07% at the final follow-up respectively (All P<0.05, Mann-Whitney U test). Ordinal Logistic regression analysis showed that female patients, two-level surgery, C4/5 surgery, and anterior cervical plating were significant risk factors for post-operative dysphagia (all P<0.05). CONCLUSION: Comparing ACDF with a plate, CDR with a Prestige LP can significantly reduce both transient and persistent post-operative dysphagia. Female patients, two-level surgery, C4/5 surgery and anterior cervical plating were associated with a higher incidence of dysphagia. Future prospective, randomized, controlled studies are needed to further validate these findings.

[PRELIMINARY EFFECTIVENESS OF POLYAMINOACID/NANO-HYDROXYAPATITE/CALCIUM SULFATE CAGE IN LUMBAR FUSION SURGERY].

OBJECTIVE: To discuss the early effectiveness of polyaminoacid/nano-hydroxyapatite/calcium sulfate (PAA/HA/CS) Cage (PHC Cage) in lumbar fusion surgery. METHODS: Thirty cases undergoing lumbar fusion of single segment between March and September 2014 were enrolled in this study. The patients were randomly divided into the trial group (n = 20) and the control group (n = 10). The PHC Cage was implanted in the trial group, while the polyetheretherketone (PEEK) Cage was implanted in the control group. The patients of 2 groups mainly presented lumbocrural pain and lower limb radiation pain or numbness. There was no significant difference in gender, age, type, affected segment, disease duration, preoperative intervertebral height, the lordosis angle of fusion segments, and the Oswestry Disability Index (ODI) between 2 groups (P > 0.05). Lateral lumbar X-ray films and three dimensional CT were taken preoperatively and at 1 week and 3, 6, and 12 months postoperatively. The intervertebral height and the lordosis angle of fusion segments at 1 week and 3, 6, and 12 months after operation and ODI at 3, 6, and 12 months after operation were measured; and the bone graft fusion rate was evaluated according to Brantigan criteria. RESULTS: There was no significant difference in operation time, intraoperative blood loss, and the amount of autologous blood transfusion between 2 groups (P > 0.05). Healing by first intention as obtained in 30 cses. All patients were followd up 12 months. The intervertebral height of fusion segments, the lordosis angle of fusion segments, and ODI at each time point after operation were significantly improved when compared with preoperative ones (P < 0.05). The ODI showed significant difference between 3 months and 6, 12 months (P < 0.05), but there was no significant difference between the other time points after operation (P > 0.05). There was no significant difference in the intervertebral height and the lordosis angle of fusion segments between groups at different time points (P > 0.05). There was no significant difference in the above indexes between the trial group and the control group at each time point (P > 0.05). At last follow-up, 5 cases were rated as Brantigan grade E, 13 cases as grade D, and 2 cases as grade C in the trial group; 4 cases were rated grade E, 5 cases as grade D, and 1 case as grade C in the control group. The bone fusion rate was 90% in 2 groups. CONCLUSION: The PHC Cage can effectively restore and maintain the disc height of fusion segment, normal sequence and biomechanical stability of the lumbar spine. The PHC Cage is similar to the PEEK Cage and has good clinical outcome in short-term follow-up.

Anterior Reduction, Discectomy, and Three Cortical Iliac Bone Grafting With Instrumentation to Treat A Huge Tear Drop Fracture of the Axis: A Case Report and Literature Review.

Fractures of the axis body have been little reported and treatment strategies remain controversial and individualized. Not more than 10 cases of huge tear drop fracture of the axis (HTDFA) have been reported in previous studies and the treatment method varies from conservative treatment to an anterior, or posterior, approach surgery. Considering the sparse knowledge of HTDFA, we present a special case report to share our experience and to explore the safety and effectiveness of anterior reduction and fusion to treat HTDFA. A 24-year-old man was referred to our department; he presented with neck pain lasting for 12 h since being involved in a roll-over motor vehicle accident. His neck movement was limited but there was no neurological compromise. Physical examination of the patient showed myodynamia of four limbs Grade 5, Hoffmann sign (-), and Babinski sign (-). Three-dimensional reconstruction computed tomography (CT) confirmed a huge tear drop fracture of the anterior-inferior corner of the axis and discontinuity of the cortex of the axis. After discussion with the spinal surgeon team in the department and an effective conversation with the patient, surgery involving anterior reduction, discectomy, and three cortical iliac bone grafts with instrumentation after transnasal induction of general anesthesia was performed. The patient was instructed to wear a cervical collar until he returned to our department for a follow-up examination some 3 months after surgery. The 3-month postoperative x-ray and CT scan showed a good position of the implant and bony fusion at the C2/3 segment. Anterior reduction, discectomy, and three cortical iliac bone grafts with instrumentation to treat HTDFA are effective, safe, and simple. Of course, longer follow-up duration and more cases are warranted to verify this procedure. Anterior reduction, discectomy, and bone grafting with instrumentation are warranted for most HTDFA cases. However, if HTDFA incorporates other complex fractures, such as fracture of the posterior structure, an anterior and posterior union surgery is recommended.

Redislocation After a Failed Surgery to Treat C6/7 Fracture-Dislocation With Pedicular Fracture of the C6 Vertebra: Case Report of a Successful Revision Surgery, Analysis of the Causes, and Discussion of Revision Surgical Strategies.

Cervical spinal fracture-dislocation with pedicular fracture of the vertebra has been little reported and the management of such a patient is difficult. Considering the little knowledge of this area, we present this special case of a successful revision surgery for the treatment of redislocation after a failed surgery to treat C6/7 fracture-dislocation with pedicular fracture of the C6 vertebra to share our experience.A 45-year-old male patient presented to our hospital with history of neck pain for 4 months. According to his medical records, he was involved in an architectural accident and diagnosed with C6/7 fracture-dislocation with pedicular fracture of the C6 vertebra (ASIA: D). A surgery of posterior lateral mass screw fixation (bilateral in C5 and C7; left side in C6) was performed in a different institution. However, 4 months after his primary surgery, he was still troubled by serious neck pain and muscle weakness in all right side limbs. The physical examination of the patient showed hypoesthesia in the right side limbs, myodynamia of the right side limbs weakened to Grade 4. Cervical X-rays, computed tomography (CT), and magnetic resonance imaging confirmed the redislocation of C6/7. A successful revision surgery of anterior cervical corpectomy and fusion (ACCF) with nanohydroxyapatite/polyamide 66 composite fulfilled with vertebral autograft plus anterior plate was performed. The 3 months postoperative X-rays and CT scan showed the good position of the implant and bony fusion. The patient's neck pain was relived and the neurological function recovered to ASIA E grade at the 3rd month follow-up.ACCF with nanohydroxyapatite/polyamide 66 composite fulfilled with vertebral autograft plus anterior plate is effective for the treatment of redislocation after a failed surgery in patients of fracture-dislocation with pedicular fracture. The best method to avoid such a failed surgery is a combined anterior-posterior approach surgery in our opinion.