[show abstract][hide abstract] ABSTRACT: To evaluate the effect of polymethylmethacrylate (PMMA) augmentation on cervical stability after anterior cervical interbody fusion (ACIF) before and after fatigue.
Twelve porcine cervical spines (C3-7) were subjected to testing angular displacement parameters, including the range of motion (ROM), neutral zone (NZ), and elastic zone (EZ), in nondestructive flexion and extension, right/left lateral bending, and left/right rotation on Motion Analysis motion capture system and MTS-858 servo-hydraulic testing machine. Intact cervical spines served as control group (group A); one-level discectomy and fusion was performed with anterior plate fixation based on group A as group B; flexion and extension, left/right lateral bending (5 000 cycles) fatigue testing based on group B as group C; the augmentation screw channel was used based on group C as group D; and flexion and extension, left/right lateral bending fatigue testing were performed based on group D as group E.
The ROM, NZ, and EZ in group A were significantly different from those in other groups (P < 0.05) at flexion/extension, left/right bending, and left/right rotation. The ROM, NZ, and EZ in group B were significantly smaller than those in group C (P < 0.05) in flexion/extension, left/right bending, and left/right rotation, but there was no significant difference when compared with group D (P > 0.05). The ROM and NZ in flexion/extension and the EZ in flexion in group B were significant smaller than those in group E (P < 0.05), but there was no significant difference in the other indexes (P > 0.05). The ROM, NZ, and EZ in group C in flexion and extension, left/right lateral bending, and left/right rotation were significantly higher than those in groups D and E (P < 0.05). The ROM and NZ in flexion and extension and left/right lateral bending, and the ROM in left/right rotation, and the EZ in flexion and extension, right bending, and left/right rotation in group D were significantly smaller than those in group E (P < 0.05), but there was no significant difference in the other indexes (P > 0.05).
PMMA augmentation can significantly increase the instant cervical stability and provide a biomechanics basis in cervical anterior plate fixation.
Zhongguo xiu fu chong jian wai ke za zhi = Zhongguo xiufu chongjian waike zazhi = Chinese journal of reparative and reconstructive surgery 10/2010; 24(10):1174-9.
[show abstract][hide abstract] ABSTRACT: Anterior Cervical Interbody Fusion (ACIF) has become increasingly popular over the last decade for cervical degenerative disease. The purpose of this study was to determine if augmenting conventional vertebrae screws with polymethylmethacrylate (PMMA) bone cement can further improve the fixation strength before and after fatigue so as to provide biomechanical characteristics for screw loose revision surgery and preventive augmentation. The results of this study indicated that PMMA augmentation could significantly increase the instant cervical stability and anti-fatigue ability after ACIF.
[show abstract][hide abstract] ABSTRACT: To describe the morphometry of iliac columns for transiliac screw and to testify the conformity among the anatomic measurement, two-dimensional (2D) and three-dimensional (3D) computed tomography.
We evaluated the length, inner width, and angle of three screw trajectories starting at the iliac tubercle, posterior superior iliac spine, and posterior inferior iliac spine toward the anterior inferior iliac spine. Measurements were made on specimen, two- and 3D computed tomography using 18 embalmed cadaveric pelves.
There was no significant difference among three measure methods. The path between the posterior superior iliac spine and anterior inferior iliac spine had the largest iliac column length, with 135 mm in male and 110 mm in female. The canal allowed placement of 8-mm screw in male and 6.5 mm in female with the angle of 25 degrees laterally directed from the midsagittal plane. The line between the posterior inferior iliac spine and anterior inferior iliac spine was below or just located at the top of greater sciatic notch in the majority measurements. The safe section for transiliac screw approximately located above the greater sciatic notch and could be divided into anterior and posterior parts.
The measurements among anatomic measurement, 2D and 3D computed tomography are consistent. The screw path from the posterior superior iliac spine toward anterior inferior iliac spine provided the longest anchor site. At the same time, the line between the posterior inferior iliac spine and anterior inferior iliac spine is not available for transiliac screw insertion of eastern population. The posterior of the safe section also can be regarded as another ilium anchorage area for transiliac screws.
[show abstract][hide abstract] ABSTRACT: There are few articles in the literature concerning anterior instrumentation in the surgical management of spinal tuberculosis in the exudative stage. So we report here 23 cases of active thoracolumbar spinal tuberculosis treated by one-stage anterior interbody autografting and instrumentation to verify the importance of early reconstruction of spinal stability and to evaluate the results of one-stage interbody autografting and anterior instrumentation in the surgical management of the exudative stage of throracolumbar spinal tuberculosis. Twenty-three patients, including two children (9 and 15 years old, respectively) and 21 adults with thoracolumbar spinal tuberculosis were treated surgically. T9 to L4 spinal segments were affected, and MRI/CT showed evident collapse of the vertebrae because of tuberculous destruction and paravertebral abscess. Neurological deficits were found in 15 patients. Before surgery, patients received standard anti-tuberculosis chemotherapy for 2 to 3 weeks. Under general endotracheal anaesthesia, the patients were placed in right recumbent positions, and a transthoracic, lateral extracavitary or extrapleural approach was chosen according to the tuberculosis lesion segment. After exposure, the tuberculous lesion region, including the collapsed vertebrae and in-between intervertebral disc, was almost completely resected in order to release the segmental spinal cord. Then, autologous iliac, rib or fibular graft was harvested to complete interbody fusion, and an anterior titanium-alloy plate-screw system was used to reconstruct the stability of the affected segments. Anti-tuberculosis chemotherapy was continued for at least 9 months, and the patients were supported with thoracolumbosacral orthosis for 6 months after surgery. All patients were followed up for an average of 2 years. All 23 cases were healed without chronic sinus formation or any recurrence of tuberculosis during the follow-up period. Spinal fusion occurred at a mean of 3.8 months after surgery. Of all patients with neurological deficits, 14 patients showed obvious improvement; only one patient with Frankel C lesion remained unchanged, but none of the patients got worse. During the follow-up period, a mean of 18 degrees of kyphosis correction was achieved after surgery in the adult group. Moderate progressive kyphosis because of this procedure fusion occurred postoperatively in a 9-year-old child after 2 1/2 years; another 15-year-old child did not demonstrate this phenomenon. Except for the early loosening of one screw in two cases (which did not affect the reconstruction of spinal stability), no other complications associated with this procedure were found during follow-up. Early reconstruction of spinal stability plays an important role in the surgical management of spinal tuberculosis. One-stage anterior interbody autografting and instrumentation in the surgical management of the exudative stage of spinal tuberculosis show more advantages in selected patients, but supplementary posterior fusion should be considered to prevent postoperative kyphosis when this procedure is performed in children.
European Spine Journal 04/2004; 13(2):114-21. · 2.13 Impact Factor
[show abstract][hide abstract] ABSTRACT: A clinical follow-up study was performed to evaluate lumbar disc nucleus replacement clinically and functionally. The objective was to assess the clinical efficacy of the prosthetic disc nucleus (PDN) for treatment of lumbar disc herniation. The PDN was designed to treat patients suffering from disc herniation and/or degeneration. Clinical trials for PDN were first conducted in 1996, and the results showed that the PDN device was effective in most of the patients who were implanted. These studies had been carried out with patients who were implanted with a pair of the devices. The main complication was device migration. Therefore, a follow-up study based on a single PDN device implantation was designed to evaluate its clinical result. Forty-five patients with lumbar disc herniation were implanted with one PDN device from March 2002 to December 2002. Thirty (66.7%) patients came to the clinical, functional, and radiographic 6-month follow-up examinations. Independent analysis was performed by careful review of the charts, operative notes, preoperative and postoperative radiographs, magnetic resonance images, and follow-up records of all patients. After implantation, significant proportions of patients experienced pain relief. Improvements were noted in pain intensity, walking distance, lumbar mobility, neurologic weakness, Oswestry and Prolo scores, and intervertebral disc height. No difference in work status after PDN implantation could be detected. Compared with the preoperative height, the intervertebral disc had gained 19.7% (P < 0.001). Device migration, failure, and dislocation were not noticed in any patient. A few patients had minor complications such as transient low-grade fever. Clinically, a single PDN is preferred and can effectively increase the height of the intervertebral disc in patients with lumbar disc herniation. However, long-term follow-up of PDN implantation needs to be studied.
[show abstract][hide abstract] ABSTRACT: OBJECTIVE: To compare the biomechanical differences among the atlantoaxial transarticular screw fixation (Magerl) and other posterior fixation techniques. METHODS: Seven preserved atlantoaxial-complex specimens were harvested and fixated with Magerl, Magerl plus Gallie wiring, Magerl plus Brooks wiring, pure Brooks, pure Gallie, and Halifax interlaminar clamping fixation, respectively. The torque for every fixation technique was measured at the point of five-degree rotation of the atlantoaxial joint. RESULTS: The torque for Magerl was 6.59 Nmplus minus1.14 Nm, which was significantly higher than any other pure posterior techniques including Gallie (1.74 Nmplus minus0.31 Nm). Brooks (4.06 Nmplus minus0.48 Nm) and Halifax (3.44 Nmplus minus0.87 Nm) (P<0.01), but less than Magerl plus brooks (9.94 Nmplus minus1.45 Nm) (P<0.01). No statistically significant difference was found between Magerl and Magerl plus Gallie wiring (7.61 Nmplus minus1.10 Nm) or between Brooks and Halifax. CONCLUSIONS: Compared with other pure posterior fixation techniques the atlantoaxial transarticular screw fixation technique provides more torsion-resistance capacity. It is also suggested that combined Gallie wiring do not add any biomechanical superiority to this technique.
Chinese Journal of Traumatology (English Edition) 05/2000; 3(2):89-92.