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Clinical Application of C1 Pedicle Screw and Lateral Mass Screw for Atlantoaxial Instability Patients with a Normal C1 Posterior Arch: A Prospective, Double-Blind, Randomized Controlled Trial
Proceedings of the NASS 30th Annual Meeting / The Spine Journal 15 (2015) 87S–267S of posterior atlantoaxial fusion between the two groups using a screwrod system with or without a supplemented crosslink for atlantoaxial fusion. STUDY DESIGN/SETTING: A prospective, randomized comparative study. PATIENT SAMPLE: Forty consecutive patients who underwent atlantoaxial fusion in our spine center. OUTCOME MEASURES: Fusion was confirmed based on the presence of bridging bone on CT image. METHODS: This prospective study included 40 patients of atlantoaxial instability who needed to undergo atlantoaxial fusion. From January 2013 to December 2013, patients were randomly divided into two groups (Group 1 and Group 2). The patients in Group 1 underwent an atlantoaxial fixation with a screw-rod system and fusion with structural iliac crest autograft. Patients in Group 2 underwent the similar procedure, but at the end of the surgery, we added a crosslink to connect the bilateral rods, which made the system more stable and also compressed the structural autograft bone to make contact with the bone graft bed of atlas and axis tightly. Patients were followed-up regularly. All the patients underwent CT scans and dynamic radiographs 6 months after surgery, and every 6 months thereafter till the end of the study or confirmation of fusion. If possible, a CT examination was also made 9 months after surgery. RESULTS: Twenty patients were divided into group 1, and another 20 into group 2. All the patients have been followed-up at least 12 months. At the final follow-up, only 13 (65.0%) patients were confirmed with bony fusion based on CT image in Group 1; while eighteen (90.0%) patients were confirmed with bony fusion in Group 2. All 40 (100%) patients showed no movement on dynamic radiographs, but only 31 (77.5%) patients were confirmed with fusion based on CT image. CONCLUSIONS: The assessment of fusion based on no movement on dynamic radiographs is not reliable. The confirmation of fusion should be based on the presence of bridging bone on CT image. A supplemented crosslink improves the fusion rate of posterior atlantoaxial fusion with screw-rod system. The mechanism may be that the crosslink makes the system more stable and also compresses the structural autograft bone making it contact with the bone graft bed tightly which facilitates the fusion. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. http://dx.doi.org/10.1016/j.spinee.2015.07.230
192. Clinical Application of C1 Pedicle Screw and Lateral Mass Screw for Atlantoaxial Instability Patients with a Normal C1 Posterior Arch: A Prospective, Double-Blind, Randomized Controlled Trial Liang Yan, PhD, MD1, Dingjun Hao, MD1, Baorong He, MD2; 1Xi’an Honghui Hospital, Xi’an, Shaanxi, China; 2Xi’an, China BACKGROUND CONTEXT: C1 posterior arch screw placement is one of the most effective methods for atlantoaxial instability. C1 posterior arch screw fixation techniques are divided into pedicle screw and lateral mass screw fixation. Previous studies have focused mainly on the feasibility of the anatomy and the biomechanics of the methods. PURPOSE: To compare the feasibility and clinical outcomes of C1 pedicle screw and lateral mass screw for atlantoaxial instability patients with C1 posterior arches measuring O4 mm. STUDY DESIGN/SETTING: A prospective, double-blind, randomized controlled study. PATIENT SAMPLE: A total of 140 patients with atlantoaxial instability were enrolled in a single center double-blind trial. OUTCOME MEASURES: The operation time, blood loss, intraoperative complications, JOA Score, VAS Score and bone fusion rates were assessed.
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METHODS: A total of 140 patients with atlantoaxial instability (C1 posterior arches measuring O4 mm) were enrolled in a single center doubleblind trial and randomized to receive either C1 pedicle screw fixation or lateral mass screw fixation. Patients were assessed preoperatively, at six weeks, six months, one year and three years after surgery. The operation time, blood loss, intraoperative complications, JOA Score, VAS Score and bone fusion rates were recorded. RESULTS: The operation was successful in all 140 cases, with all patients showing improvement in clinical symptoms. There were significant differences in operation time and blood loss between the 2 groups (P!0.001). The mean follow-up time was 42 months. At the final follow-up, the JOA score was significantly better than the preoperative score (mean, 14.2; P!0.05). The mean postoperative improvement rate was 88.7% and the mean VAS score was 1.7; both results were significant as compared with preoperative results (P!0.05). Bone fusion was achieved within 6 months after operation. No screw loosening, shifting, breakage, or atlantoaxial instability was observed. For the C1 lateral mass screw fixation group, 9 patients had burst bleeding of C1-2 venous plexus during surgery, and 6 patients had immediate pain and numbness at the occipitocervical region. CONCLUSIONS: C1 pedicle screw fixation is less invasive, simple, has fewer complications, and results in clinical satisfaction for atlantoaxial instability as compared with C1 lateral mass screw fixation. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. http://dx.doi.org/10.1016/j.spinee.2015.07.231
193. In Vivo Motion Characteristics of the Lower Cervical Spine During Dynamic Weight-Bearing Flexion-Extension Sean J. Driscoll, Haiqing Mao, MD, Shaobai Wang, PhD, Weiye Zhong, MD, PhD, Guoan Li, MD, Kirkham B. Wood, MD, Thomas D. Cha, MD, MBA; Massachusetts General Hospital, Boston, MA, US BACKGROUND CONTEXT: Limited research exists regarding in-vivo three-dimensional (3D) motion characteristics of the cervical spine during dynamic functional activities. Knowledge of intervertebral motion characteristics is important to better understand potential mechanical factors related to disease development and the clinical outcomes following surgical intervention (spinal fusion and disc replacement). These motion characteristics may also need to be considered when determining surgical techniques and implants to best restore native spine function. PURPOSE: The purpose of this research was to investigate the in-vivo six-degree-of-freedom (6DOF) motion characteristics of the lower cervical spine (C3-7) during dynamic weight-bearing flexion-extension using a 3D dual-fluoroscopic imaging system (DFIS). STUDY DESIGN/SETTING: In-vivo laboratory study. PATIENT SAMPLE: 10 asymptomatic subjects (6 males, 4 females, average age: 40.3610.9 years, average BMI 24.663.2 kg/m2) were recruited for this study, which had been previously approved by the authors’ Institutional Review Board. The presences of any spinal disorders, symptoms or anatomic abnormalities were used as indications for exclusion from the study. A signed consent form was obtained from each subject before testing. OUTCOME MEASURES: Dynamic range of motion (DROM) in 6DOF were calculated for each intervertebral level (C3-C4, C4-C5, C5-C6, and C6-C7) during the activity. 6DOF kinematics included three rotations: flexion-extension (FE), lateral side-bending (SB), and axial twisting; and three translations: medial-lateral (ML), anterior-posterior (AP), and superior-inferior (SI). ANOVA with repeated measures and post-hoc analysis were used to examine differences between levels. Statistical significance was defined as p!0.05. METHODS: The cervical spine was imaged using the DFIS as subjects moved dynamically through their full flexion-extension ROM. The speed
Refer to onsite Annual Meeting presentations and postmeeting proceedings for possible referenced figures and tables. Authors are responsible for accurately reporting disclosures and FDA device/drug status at time of abstract submission.
192. Clinical Application of C1 Pedicle Screw and Lateral Mass Screw for Atlantoaxial Instability Patients with a Normal C1 Posterior Arch: A Prospective, Double-Blind, Randomized Controlled Trial Liang Yan, PhD, MD1, Dingjun Hao, MD1, Baorong He, MD2; 1Xi’an Honghui Hospital, Xi’an, Shaanxi, China; 2Xi’an, China BACKGROUND CONTEXT: C1 posterior arch screw placement is one of the most effective methods for atlantoaxial instability. C1 posterior arch screw fixation techniques are divided into pedicle screw and lateral mass screw fixation. Previous studies have focused mainly on the feasibility of the anatomy and the biomechanics of the methods. PURPOSE: To compare the feasibility and clinical outcomes of C1 pedicle screw and lateral mass screw for atlantoaxial instability patients with C1 posterior arches measuring O4 mm. STUDY DESIGN/SETTING: A prospective, double-blind, randomized controlled study. PATIENT SAMPLE: A total of 140 patients with atlantoaxial instability were enrolled in a single center double-blind trial. OUTCOME MEASURES: The operation time, blood loss, intraoperative complications, JOA Score, VAS Score and bone fusion rates were assessed.
183S
METHODS: A total of 140 patients with atlantoaxial instability (C1 posterior arches measuring O4 mm) were enrolled in a single center doubleblind trial and randomized to receive either C1 pedicle screw fixation or lateral mass screw fixation. Patients were assessed preoperatively, at six weeks, six months, one year and three years after surgery. The operation time, blood loss, intraoperative complications, JOA Score, VAS Score and bone fusion rates were recorded. RESULTS: The operation was successful in all 140 cases, with all patients showing improvement in clinical symptoms. There were significant differences in operation time and blood loss between the 2 groups (P!0.001). The mean follow-up time was 42 months. At the final follow-up, the JOA score was significantly better than the preoperative score (mean, 14.2; P!0.05). The mean postoperative improvement rate was 88.7% and the mean VAS score was 1.7; both results were significant as compared with preoperative results (P!0.05). Bone fusion was achieved within 6 months after operation. No screw loosening, shifting, breakage, or atlantoaxial instability was observed. For the C1 lateral mass screw fixation group, 9 patients had burst bleeding of C1-2 venous plexus during surgery, and 6 patients had immediate pain and numbness at the occipitocervical region. CONCLUSIONS: C1 pedicle screw fixation is less invasive, simple, has fewer complications, and results in clinical satisfaction for atlantoaxial instability as compared with C1 lateral mass screw fixation. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. http://dx.doi.org/10.1016/j.spinee.2015.07.231
193. In Vivo Motion Characteristics of the Lower Cervical Spine During Dynamic Weight-Bearing Flexion-Extension Sean J. Driscoll, Haiqing Mao, MD, Shaobai Wang, PhD, Weiye Zhong, MD, PhD, Guoan Li, MD, Kirkham B. Wood, MD, Thomas D. Cha, MD, MBA; Massachusetts General Hospital, Boston, MA, US BACKGROUND CONTEXT: Limited research exists regarding in-vivo three-dimensional (3D) motion characteristics of the cervical spine during dynamic functional activities. Knowledge of intervertebral motion characteristics is important to better understand potential mechanical factors related to disease development and the clinical outcomes following surgical intervention (spinal fusion and disc replacement). These motion characteristics may also need to be considered when determining surgical techniques and implants to best restore native spine function. PURPOSE: The purpose of this research was to investigate the in-vivo six-degree-of-freedom (6DOF) motion characteristics of the lower cervical spine (C3-7) during dynamic weight-bearing flexion-extension using a 3D dual-fluoroscopic imaging system (DFIS). STUDY DESIGN/SETTING: In-vivo laboratory study. PATIENT SAMPLE: 10 asymptomatic subjects (6 males, 4 females, average age: 40.3610.9 years, average BMI 24.663.2 kg/m2) were recruited for this study, which had been previously approved by the authors’ Institutional Review Board. The presences of any spinal disorders, symptoms or anatomic abnormalities were used as indications for exclusion from the study. A signed consent form was obtained from each subject before testing. OUTCOME MEASURES: Dynamic range of motion (DROM) in 6DOF were calculated for each intervertebral level (C3-C4, C4-C5, C5-C6, and C6-C7) during the activity. 6DOF kinematics included three rotations: flexion-extension (FE), lateral side-bending (SB), and axial twisting; and three translations: medial-lateral (ML), anterior-posterior (AP), and superior-inferior (SI). ANOVA with repeated measures and post-hoc analysis were used to examine differences between levels. Statistical significance was defined as p!0.05. METHODS: The cervical spine was imaged using the DFIS as subjects moved dynamically through their full flexion-extension ROM. The speed
Refer to onsite Annual Meeting presentations and postmeeting proceedings for possible referenced figures and tables. Authors are responsible for accurately reporting disclosures and FDA device/drug status at time of abstract submission.