Factors Affecting Titanium Mesh Cage Subsidence in Single-level Anterior Cervical Corpectomy and Fusion for Ossification of the Posterior Longitudinal Ligament

Background: To analyze risk factors of titanium mesh cage (TMC) subsidence in single-level anterior cervical corpectomy and fusion (ACCF) for cervical ossification of the posterior longitudinal ligament (OPLL). Methods: Patients with cervical OPLL who were treated with single-level ACCF between January 2019 to December 2019 were retrospectively analyzed in two groups: patients with TMC subsidence as Group S, and patients with no TMC subsidence as Group N during the one-year follow-up period. The degree of distraction between decompression of the vertebral bodies and correction of the cervical curvature was measured to analyze their relationship with TMC subsidence. Results: There was no significant difference in patient demographics and complications between the two groups. The degree of distraction in Group S was significantly higher than that in Group N. The change of C2 to C7 Cobb angle (α) in Group S was significantly greater than that in Group N, and the interspinous process distance (SPD) in Group S was also significantly greater than that in Group N. The JOA score and JOA recovery rate were not statistically different between the two groups.Conclusions: Intraoperative selection of overlength TMC in single-level ACCF for OPLL, over-distraction, and excessive correction of the cervical curvature may cause TMC subsidence after surgery. No significant impact of TMC subsidence on the surgical outcome was observed during the 1-year follow-up period.

A novel anatomic titanium mesh cage for reducing the subsidence rate after anterior cervical corpectomy: a finite element study

Fusion with a titanium mesh cage (TMC) has become popular as a conventional method after cervical anterior corpectomy, but postoperative TMC subsidence has often been reported in the literature. We designed a novel anatomic cervical TMC to reduce the postoperative subsidence rate. According to the test process specified in the American Society of Testing Materials (ASTM) F2267 standard, three-dimensional finite element analysis was used to compare the anti-subsidence characteristics of a traditional TMC (TTMC) and novel TMC (NTMC). Through analysis, the relative propensity values of a device to subside (Kp) of the TTMC and NTMC were 665.5 N/mm and 1007.2 N/mm, respectively. A higher Kp measurement is generally expected to indicate that the device is more resistant to subsidence into a vertebral body. The results showed that the novel anatomic titanium mesh cage (NTMC) significantly improved the anti-subsidence performance after anterior cervical corpectomy and fusion (ACCF), which was approximately 51.3% higher than that of the traditional titanium mesh cage.

The most appropriate titanium mesh cage size for anterior spinal reconstruction after single-level lumbar total en bloc spondylectomy: a finite element analysis and cadaveric validation study

Purpose There is little information available regarding the cage diameter that can provide the most rigid construct reconstruction after total en bloc spondylectomy (TES). The aim of this study was thus to determine the most appropriate titanium mesh cage diameter for reconstruction after spondylectomy. Methods A finite element model of the single level lumbar TES was created. Six models of titanium mesh cage with diameters of 1/3, 1/2, 2/3, 3/4, 4/5 of the caudad adjacent vertebra, and 1/1 of the cephalad vertebra were tested for construct stiffness. The peak von Mises stress (MPa) at the failure point and the site of failure were measured as outcomes. A cadaveric validation study also conducted to validate the finite element model. Results For axial loading, the maximum stress points were at the titanium mesh cage, with maximum stress of 44,598 MPa, 23,505 MPa, 23,778 MPa, and 16,598 MPa, 10,172 MPa, 10,805 MPa in the 1/3, 1/2, 2/3, 3/4, 4/5, and 1/1 diameter model, respectively. For torsional load, the maximum stress point in each of the cages was identified at the rod area of the spondylectomy site, with maximum stress of 390.9 MPa (failed at 4459 cycles), 141.35 MPa, 70.098 MPa, and 88.972 MPa, 42.249 MPa, 15.827 MPa, respectively. A cadaveric validation study results were coincided with the finite element model results. Conclusion The most appropriate mesh cage diameter for reconstruction is 1/1 the diameter of the lower endplate of the adjacent cephalad vertebra, due to its ability to withstand both axial and torsional stress. According to the difficulty of large size cage insertion, a cage diameter of more than half of the upper endplate of the caudad vertebrae is acceptable in term of withstand stress. A cage diameter of 1/3 is unacceptable for reconstruction after total en bloc spondylectomy.

A novel anatomic titanium mesh cage for reducing the subsidence rate after anterior cervical corpectomy: a finite element study

Fusion with a titanium mesh cage (TMC) has become popular as a conventional method after cervical anterior corpectomy, but postoperative TMC subsidence has often been reported in the literature. We designed a novel anatomic cervical TMC to reduce the postoperative subsidence rate. According to the test process specified in the American Society of Testing Materials (ASTM) F2267 standard, three-dimensional finite element analysis was used to compare the anti-subsidence characteristics of a traditional TMC (TTMC) and novel TMC (NTMC). Through analysis, The relative propensity values of a device to subside (Kp) of the TTMC and NTMC were be 665.5 N/mm and 1007.2 N/mm, respectively. A higher Kp measurement is generally expected to indicate that the device is more resistant to subsidence into a vertebral body. The results showed that the novel anatomic titanium mesh cage (NTMC) significantly improved the anti-subsidence performance after anterior cervical corpectomy and fusion (ACCF), which was approximately 51.3% higher than that of the traditional titanium mesh cage.

A Novel Anatomic Titanium Mesh Cage for Reducing the Subsidence Rate After Anterior Cervical Corpectomy: A Finite Element Study

Background: Fusion with a titanium mesh cage (TMC) has become popular as a conventional method after cervical anterior corpectomy, but postoperative TMC subsidence has often been reported in the literature. We designed a novel anatomic cervical TMC to reduce the postoperative subsidence rate. This finite element study aims to investigate the anti-subsidence performance of a novel anatomic TMC and provide a theoretical basis for clinical application. Methods: According to the test process specified in the ASTM F2267 standard, three-dimensional finite element analysis was used to compare the anti-subsidence characteristics of a traditional TMC (TTMC) and novel TMC (NTMC). Abaqus software was used for the mesh, and the modulus of elasticity, Poisson's ratio and other material coefficients of each part were input into the model. Solidworks software was used to establish the TTMC and NTMC models and construct the two three-dimensional finite element models of TMC subsidence testing mentioned above. Through analysis, the relationships between the stiffness of the intervertebral body fusion device (Kd) and the stiffness of the polyurethane foam blocks (Ks) of the TTMC and NTMC were derived, respectively. Results: After fitting the linear segment, the Kd values of the TTMC and NTMC were 37314 N/mm and 89124 N/mm, respectively. After calculation, the Ks values of the TTMC and NTMC were 653.83 N/mm and 995.95 N/mm, respectively. The Kp values of the TTMC and NTMC were calculated to be 665.5 N/mm and 1007.2 N/mm according to the formula. Conclusion: The reported novel anatomic titanium mesh cage (NTMC) significantly improved the anti-subsidence performance after ACCF, which was approximately 51.3% higher than that of the traditional titanium mesh cage.

A Novel Anatomic Titanium Mesh Cage for Reducing the Subsidence Rate After Anterior Cervical Corpectomy: A Finite Element Study

Background: Fusion with a titanium mesh cage (TMC) has become popular as a conventional method after cervical anterior corpectomy, but postoperative TMC subsidence has often been reported in the literature. We designed a novel anatomic cervical TMC to reduce the postoperative subsidence rate. This finite element study aims to investigate the anti-subsidence performance of a novel anatomic TMC and provide a theoretical basis for clinical application. Methods: According to the test process specified in the ASTM F2267 standard, three-dimensional finite element analysis was used to compare the anti-subsidence characteristics of a traditional TMC (TTMC) and novel TMC (NTMC). Abaqus software was used for the mesh, and the modulus of elasticity, Poisson's ratio and other material coefficients of each part were input into the model. Solidworks software was used to establish the TTMC and NTMC models and construct the two three-dimensional finite element models of TMC subsidence testing mentioned above. Through analysis, the relationships between the stiffness of the intervertebral body fusion device (Kd) and the stiffness of the polyurethane foam blocks (Ks) of the TTMC and NTMC were derived, respectively. Results: After fitting the linear segment, the Kd values of the TTMC and NTMC were 37314 N/mm and 89124 N/mm, respectively. After calculation, the Ks values of the TTMC and NTMC were 653.83 N/mm and 995.95 N/mm, respectively. The Kp values of the TTMC and NTMC were calculated to be 665.5 N/mm and 1007.2 N/mm according to the formula. Conclusion: The reported novel anatomic titanium mesh cage (NTMC) significantly improved the anti-subsidence performance after ACCF, which was approximately 51.3% higher than that of the traditional titanium mesh cage.