The research progress of posterior atlantoaxial internal fixation techniques / 医学研究生学报

Atlantoaxial instability or dislocation is a common upper cervical disease which can lead to serious outcomes including sensory and motor deficit or even sudden death. Therefore, active surgical intervention is often recommended. The most popular surgical procedure for atlantoaxial instability is posterior bone graft and internal fixation. Posterior stabilization techniques mainly include wiring techniques, interlaminar clamp fixation, C1-C2 transarticular screw fixation (Magerl technique), screw-plate systems, and screw-rod systems. Each technique has its advantage and shortcoming. The screw-rod systems, along with various modifications, has become the most popular internal fixation technique for posterior atlantoaxial stabilization in clinic. This article reviews the evolution, characteristics and new advancement of some prevail posterior atlantoaxial fixation techniques in purpose of giving a reference for surgeons to have a better understanding of posterior fixation techniques and make a reasonable choice in clinical practice.

Diagnosis and treatment for complicated atlantoaxial dislocation / 中华外科杂志

<p><b>OBJECTIVE</b>To explore the clinical characteristics and treatment methods for complicated atlantoaxial dislocation.</p><p><b>METHODS</b>A retrospective evaluation was done to summarize and analyze the clinical characteristics and complicated factors of 54 patients with complicated atlantoaxial dislocation who could not to be treated effectively by using conventional therapy in our hospital from February 2005 to October 2008. According to different complicated factors, different treatment methods mainly including transoral atlantoaxial reduction plate-III (TARP-III) operation, decompression procedure with deep grinding guided by computer aided design-rapid prototyping (CAD-RP), screw placement technique with CAD-RP guide plate and extensile approach surgery were performed.</p><p><b>RESULTS</b>The average follow-up period was 24 months. Among 54 cases, 48 cases achieved immediate anatomic reduction completely and 6 cases almost achieved anatomical reduction. All the compressed spinal cords were decompressed sufficiently. The decompression rate was 86.0% and the improvement rate of nerve function was 77.8%. Two cases suffered postoperative intracranial infection.</p><p><b>CONCLUSION</b>Some cases of complicated atlantoaxial dislocation can be effectively treated by using TARP-III operation, decompression procedure with deep grinding guided by CAD-RP, individualized screw placement technique with CAD-RP guide plate and extensile approach surgery.</p>

Treatment of traumatic intervertebrae disk herniation in cervical thoracic junction through transforminal approach / 中国骨伤

<p><b>OBJECTIVE</b>To investigate the treatment for traumatic intervertebrae disk herniation in cervical thoracic junction.</p><p><b>METHODS</b>From 2003 to 2008, there were 10 patients with trautimatic intervertebral disk herniation in cervical thoracic junction, which included 6 males and 4 females, aged from 23 to 66 years (means 41.5 years). All of them were performed through the transforminal approach combined with internal fixation. After operation all patient underwent hyperbaric oxygen treatment. The function of spine was evaluated by JOA score system.</p><p><b>RESULTS</b>All patients were followed up for 8 to 16 months(means 13 months). All patients got recovery of spine function to some extent except one case with complete spine damaged. The JOA scores was improved from (8 +/- 3) before operation to (15 +/- 2) after operation.</p><p><b>CONCLUSION</b>Early and effective treatment by transforminal operation could be helpful for the recovery of spine function.</p>

The synthetic typing and its clinical application in atlantoaxial dislocation / 中华外科杂志

<p><b>OBJECTIVE</b>To evaluate the synthetic typing and the treatment strategy for atlantoaxial dislocation.</p><p><b>METHODS</b>The synthetic typing of atlantoaxial dislocation was worked out on the base of pathogenesis typing, Fielding imaging typing, and clinical typing, named PIR typing system (Pathogenesis, Imaging, and Reduction). Ninety-three patients with atlantoaxial dislocation were treated according to this typing system.</p><p><b>RESULTS</b>Nine cases of type-II dens fracture were treated with hollow screw fixation. Bone union was accomplished at the follow-up of three months in all the patients, only with slight limitation of cervical motion. Un-retrieved Fielding I -degree dislocation was found in one case. Among the thirty-four patients treated with trans-oropharyngeal atlantoaxial reduction plate system (TARP), 32 obtained complete atlantoaxial reduction and fusion three months after operation. Atlantoaxial dislocation recurred in the other two cases because of screw loosening and the problem was solved through revision operations. Four patients in non-reducible type underwent anterior and/or posterior decompression. T heir neurological improved after operation but their atlantoaxial joints remained dislocated, and one case complicated with intracranial infection.</p><p><b>CONCLUSIONS</b>Via the synthetic PIR typing system, atlantoaxial dislocation can be better classified according to its pathogenesis, imaging manifestation and mechanic stability. This system can also be served as a guide for clinical treatment. Anterior TARP operation and posterior atlantoaxial trans-pedicle screw-rod fixation are the main methods for the treatment of atlantoaxial dislocation.</p>

Anatomic evaluation the entry point of C2 pedicle screw / 中华外科杂志

<p><b>OBJECTIVE</b>To study the relevant position of C(2) pedicle to C(2) inferior articular process, set up a technique of C(2) pedicle screw placement with the inferior articular process of axis as an anatomic landmark.</p><p><b>METHODS</b>Fifty C(2) bone specimens were used to measure the distance from the sagittal midline to the medial border, the midpoint and the lateral border of C(2) inferior articular process or C(2) pedicle; the width and the height of the C(2) pedicle were also evaluated. The anatomic relation between the measurements data of C(2) pedicle and that of C(2) inferior articular process were analyzed, and the technique of C(2) pedicle screw fixation was established.</p><p><b>RESULTS</b>The medial border of C(2) inferior articular process was averaged (3.67 +/- 0.41) mm lateral to that of C(2) pedicle, and the midpoint C(2) inferior articular process was averaged (1.15 +/- 0.44) mm lateral to the lateral border of C(2) pedicle, respectively. Using the C(2) inferior articular process as landmark, two techniques was established for C(2) pedicle screw placement. The entry point of method A was located in 2 mm medial and superior to the central point of C(2) inferior articular process; the entry point of method B was at the crossing point of the medial border C(2) inferior articular process with the superior quarter of C(2) inferior articular process.</p><p><b>CONCLUSIONS</b>There is a steady anatomic relation between C(2) pedicle and C(2) inferior articular process, the C(2) inferior articular process could be as a convenient key anatomic landmark to determine the location of C(2) pedicle and the position of C(2) pedicle screw entry point.</p>

Anatomic identification of the location of the pedicle of atlas with the lateral mass of C2 to C4 as the landmark / 中华外科杂志

<p><b>OBJECTIVE</b>To study the relevant position of the pedicle of C1 to the lateral mass of C(2-4), set up an identification technique for the entry point decision of C1 pedicle screw by using the lateral mass of C(2-4) as anatomic landmarks.</p><p><b>METHODS</b>Twenty cadaver specimens were used to measure the distance from the sagittal midline of spine to the medial border, the midpoint and the lateral border of C1 pedicle or the lateral mass of C2, C3 or C4. The anatomic relation between the measurements data of C1 pedicle and that of the lateral masses of the cervical vertebrae were analyzed, and the technique of C1 pedicle screw fixation was established.</p><p><b>RESULTS</b>The average medial border of the lateral mass of C2, C3 and C4 was 0.37 mm, 0.27 mm and 0.24 mm lateral to that of C1 pedicle, the average midpoint of the lateral mass of C2, C3 and C4 was 1.18 mm, 1.41 mm and 1.74 mm lateral to that of C1 pedicle, and the average lateral border of the lateral mass of C2, C3 and C4 was 1.96 mm, 2.54 mm and 3.24 mm lateral to that of C1 pedicle, respectively.</p><p><b>CONCLUSION</b>There is a steady anatomic location relation between C1 pedicle and the lateral mass of C2, C3 or C4. As well as the lateral mass of C2, the lateral mass of C3 or that of C4 could be convenient anatomic landmarks to determine the location of C1 pedicle and the position of C1 pedicle screw entry point.</p>