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>

The anatomical study of transoral atlantoaxial reduction plate internal fixation / 中华创伤杂志(英文版)

<p><b>OBJECTIVE</b>To study relevant anatomical features of the structures involved in transoral atlanto-axial reduction plate (TARP) internal fixation through transoral approach for treating irreducible atlanto-axial dislocation and providing anatomical basis for the clinical application of TARP.</p><p><b>METHODS</b>Ten fresh craniocervical specimens were microsurgically dissected layer by layer through transoral approach. The stratification of the posterior pharyngeal wall, the course of the vertebral artery, anatomical relationships of the adjacent structures of the atlas and axis, and the closely relevant anatomical parameters for TARP internal fixation were measured.</p><p><b>RESULTS</b>The posterior pharyngeal wall consisted of two layers and two interspaces: the mucosa, prevertebral fascia, retropharyngeal space, and prevertebral space. The range from the anterior edge of the foramen magnum to C(3) could be exposed by this approach. The thickness of the posterior pharyngeal wall was (3.6+/-0.3) mm (ranging 2.9-4.3 mm) at the anterior tubercle of C1, (6.1+/-0.4) mm (ranging 5.2-7.1 mm) at the lateral mass of C(1) and (5.5+/-0.4) mm (ranging 4.3-6.5 mm) at the central part of C(2), respectively. The distance from the incisor tooth to the anterior tubercle of C(1), C(1) screw entry point, and C(2)screw entry point was (82.5+/-7.8) mm (ranging 71.4-96.2 mm), (90.1+/-3.8) mm (ranging 82.2-96.3 mm), and (89.0+/-4.1) mm (ranging 81.3-95.3 mm), respectively. The distance between the vertebral artery at the atlas and the midline was (25.2+/- 2.3) mm (ranging 20.4-29.7 mm) and that between the vertebral artery at the axis and the midline was (18.4+/- 2.6) mm (ranging 13.1-23.0 mm). The allowed width of the atlas and axis for exposure was (39.4+/-2.2) mm (ranging 36.2-42.7 mm) and (39.0+/-2.1) mm (ranging 35.8-42.3 mm), respectively. The distance (a) between the two atlas screw insertion points (center of anterior aspect of C(1) lateral mass) was (31.4+/-3.3) mm (ranging 25.4-36.6 mm). The vertical distance (b) between the line connecting the two C(1) screw entry points and that connecting the two C(2) screw entry points (at the central part of the vertebrae, namely 3-4 mm lateral to the midline of C(2) vertebrae) was (21.3+/-2.7) mm (ranging 19.4-24.3 mm), with an a/b ratio of 1.3-1.5. The screws of TARP had a lateral tilt of 12.2 degrees+/-0.4 degrees(ranging 10.2 degrees-14.6 degrees) at C(1) and a medial tilt of 7.3 degrees+/-0.3 degrees (ranging 5.1 degrees-9.4 degrees) at C(2) relative to the coronal plane.</p><p><b>CONCLUSIONS</b>An atlanto-axial surgery through transoral approach is safe and feasible. This approach is suitable for an anterior TARP internal fixation, and the design of the internal fixation system should be based on the above anatomical data.</p>

Transoral atlantoaxial reduction plate fixation for irreducible atlantoaxial dislocation / 中华创伤杂志(英文版)

<p><b>OBJECTIVE</b>To design a clinically applicable transoralpharyngeal atlantoaxial reduction plate (TARP), introduce the operation procedure, and evaluate its preliminary clinical effects.</p><p><b>METHODS</b>A novel TARP system, including butterfly titanium alloy plate, self-locking screws, atlantoaxial reductor and other operational instruments was developed. This system was applied clinically on five patients with irreducible atlantoaxial dislocation of congenital or traumatic origin. During operation, the reduction was completed by the combined action of the plate and the atlantoaxial reductor after transoral joint release and cord decompression. Bone graft granules were implanted between the bilateral atlantoaxial joints and TARP was used to immobilize subsequently the atlas and axis.</p><p><b>RESULTS</b>Clinical application demonstrated that TARP could induce instant reduction and that the method was operationally feasible and its postoperational effect was satisfactory.</p><p><b>CONCLUSIONS</b>The design of TARP is novel. The operational procedure is simple and easy to use. Furthermore, instant reduction can be completed during the operation and the fixation is relatively stable. TARP is an ideal alternative for irreducible atlantoaxial dislocation and may have excellent prospects for further clinical applications.</p>

Surgical anatomy of transoral atlantoaxial reduction plate internal fixation / 中华外科杂志

<p><b>OBJECTIVE</b>To provide anatomical data for transoral atlantoaxial reduction plate internal fixation.</p><p><b>METHOD</b>Microsurgical dissecting was performed on 10 fresh craniocervical specimens layer by layer according to transoral approach. Stratification of posterior pharyngeal wall, course of vertebral artery, adjacent relationships of atlas and axis and correlative anatomical parameters of internal fixation to atlantoaxial joint were observed.</p><p><b>RESULT</b>(1) Posterior pharyngeal wall consisted of 2 layers and 2 interspace: mucosa, anterior fascia of vertebrae, posterior interspace of pharynx and anterior interspace of vertebrae. (2) The range from anterior rim of foramen magnum to C3 could be exposed by this approach. (3) The distance between the vertebral artery at atlas and midline was (25.2 +/- 2.3) mm and that between the vertebral artery at axis and midline was (18.4 +/- 2.6) mm. (4) The width of atlas and that of axis could be exposed respectively to (39.4 +/- 2.2) mm and (39.0 +/- 2.1) mm. The distance (a) between 2 atlas screw inserting points (center of anterior aspect of C-1 lateral mass) was (31.4 +/- 3.3) mm. The vertical distance (b) between the connecting line of 2 atlas screw inserting points and that of 2 axis screw inserting points (at the central part of the vertebrae which was 3 - 4 mm lateral to the midline of C-2 vertebrae) was (18.7 +/- 2.7) mm. The odds of a/b was 1.5 approximately 1.7.</p><p><b>CONCLUSIONS</b>Anterior atlantoaxial plate internal fixation through transoral approach is suitable and feasible. The design of the plate should be based on the above data.</p>

Design and preliminary clinical application of transoralpharyngeal atlantoaxial reduction plate / 中华外科杂志

<p><b>OBJECTIVE</b>To design transoralpharyngeal atlantoaxial reduction plate (TARP), evaluate its biomechanical performance and observe its preliminary clinical effect.</p><p><b>METHODS</b>A brand-new TARP system was designed, including butterfly titanium alloy plate, self-locking screws, atlantoaxial reductor and other operation instruments. Twelve fresh occipital bone-C(3) specimen were designed for biomechanical test including range of motion (ROM) (n = 6) and screw pull-out strength (n = 12). Preliminary clinical application of TARP was reported.</p><p><b>RESULTS</b>The reduction mechanism of the TARP system was designed cleverly. TARP had equal effect with Magerl + Brooks and it was more stable than the other three clinically widely used atlantoaxial fixators: Magerl, Brooks and anterior transarticular screw fixation through C(2) vertebral body. TARP's C(1) and C(2) screws were strong enough for atlantoaxial arthrodesis and their antipull-out performance was excellent. Clinical application on irreducible atlantoaxial dislocation proved that TARP had the function of instant reduction, the operation was feasible and the operation effect was significant.</p><p><b>CONCLUSION</b>TARP's design is novel and it has excellent biomechanical performance. The operation procedure is simple and reasonable. Furthermore, instant reduction could be completed during the operation and the fixation is strong. Above all, TARP is creative and will have excellent prospect.</p>