Effectiveness and Safety of Mobile Artificial Cervical Vertebrae Replacement for Patients With Cervical Spondylosis

Study Overview
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Brief Summary
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The research team designed an artificial cervical joint prosthesis suitable for subtotal resection of the lower cervical vertebral body. Previous studies regarding cadaver and animal experiments have found that this artificial joint not only retains the normal range of physiological motion of the joint, but also has good stability. Preliminary studies have shown that the designed joints are sufficiently safe and stable. The titanium materials for joints have been verified for their toxicology in long-term clinical trials and have been monitored under relevant national testing agencies in China.

Detailed Description
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Artificial cervical disc technology has achieved certain clinical effects in the treatment of single-segment lesions of the lower cervical spine. However, simple artificial cervical disc replacement is only applicable for single-segment disc herniation, but not for two adjacent cervical segmental lesions, concurrent with vertebral hyperplasia and ossification of the posterior longitudinal ligament in the cervical spine. Traditional vertebral corpectomy and bone graft fusion can reduce the mobility of the cervical spine. Therefore, non-fusion fixation for such diseases has been a key issue to improve the efficacy of surgical treatments. To this end, the research team designed an artificial cervical joint prosthesis suitable for subtotal resection of the lower cervical vertebral body. Previous studies regarding cadaver and animal experiments have found that this artificial joint not only retains the normal range of physiological motion of the joint, but also has good stability. Preliminary studies have shown that the designed joints are sufficiently safe and stable. The titanium materials for joints have been verified for their toxicology in long-term clinical trials and have been monitored under relevant national testing agencies in China. To serve clinical patients faster and ensure that the trial design is safe, this study is designed to observe the effectiveness and safety of mobile artificial cervical vertebrae replacement for patients with cervical spondylosis.

Official Title
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Effectiveness and Safety of Mobile Artificial Cervical Vertebrae Replacement for Patients With Cervical Spondylosis: Study Protocol for a Prospective, Non-randomized Controlled, Clinical Trial

Conditions
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Cervical Spondylosis

Intervention / Treatment
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* Procedure: mobile artificial cervical vertebrae replacement
* Procedure: anterior cervical corpectomy and fusion


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: (1)Age: 18-70 years, irrespective of sex; (2)For mobile artificial cervical vertebrae replacement, patients with cervical spondylosis who are planned to undergo anterior cervical corpectomy and resection of two adjacent intervertebral discs; (3)For anterior cervical corpectomy and fusion, patients with cervical spondylosis who are planned to undergo anterior cervical corpectomy and resection of two adjacent intervertebral discs; Exclusion Criteria: (1) Patients who have participated in other clinical studies 3 months before the inception of the study; (2) Abnormalities in liver and kidney functions (aspartate aminotransferase, alanine aminotransferase, blood creatinine and urea nitrogen levels are 1.5 times higher than normal); (3) Obvious abnormalities in the blood system; (4) Abuse of drugs or ethanol; (5) Patients who have brain disorders, abnormal judging ability, or cannot cooperate with the observer; (6) Coronary heart disease or severe kidney disease; (7) Severe metabolic diseases and endocrine diseases that are out of drug control; (8) Pregnant and lactating women and couples who are about to become pregnant in the near future; (9) Severe lung diseases such as asthma and lung dysfunction; (10) Immunodeficiency; (11) Single-segment intervertebral disc herniation or compression; (12) 3 or more vertebral segments herniated or spinal cord compression due to ligament ossification; (13) Active infection (systemic or local cervical spine) or a history of local cervical spine infection; (14) A history of anterior cervical surgery; (15) Patients with a need for posterior surgical treatments, with severe arthritis of the cervical spine joint process, and with spinal cord compression on the back; (16) Severe osteoporosis; (17) Cervical vertebra deformity; (18) A history of ossification of the posterior longitudinal ligament of the cervical spine, ankylosing spondylitis, and heterotopic ossification; (19) Severe cervical spine instability or trauma to the posterior structure of the cervical spine, and cervical spondylolisthesis; (20) Abnormal soft tissues anterior to the cervical spine (tracheal or esophageal malformations, and a history of radiotherapy), and obesity; (21) Allergy to prosthetic materials; (22) Patients who have tumors that cannot be completely resected and patients who are predicted to suffer prosthetic loosening during survival time; (23) Other contraindications for surgery.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 70 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: Participants are assigned to one of two or more groups in parallel for the duration of the study
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Trial group<br>20 patients with cervical spondylosis undergoing mobile artificial cervical vertebrae replacement | Procedure: mobile artificial cervical vertebrae replacement<br>* Position: The patient is in a supine position with the neck hyperextended, ensuring his/her neck and shoulders in a stable and neutral position before surgery and the cervical spine in a physiological curvature position. Anesthesia: General anesthesia via oral tracheal intubation. Surgical approach: Anterior cervical spine approach through the space between the visceral sheath and the vascular sheath. Surgical method: Two intervertebral discs with adjacent lesions and part of the vertebral body between them will be removed. A curette is used to carefully strike off the annulus fibrosus and cartilage on the surface of the adjacent upper and lower endplates. Intraoperatively, the midlines of the segment and the vertebra to be replaced should be mapped out. When decompression, the midline for decompression should not be deviated from the planned midlines.<br>* Other names: Trial group;|
| Experimental: Control group<br>20 patients with cervical spondylosis undergoing anterior cervical corpectomy and fusion | Procedure: anterior cervical corpectomy and fusion<br>* Position: The patient is in a supine position with the neck hyperextended. Anesthesia: General anesthesia via oral tracheal intubation. Surgical approach: Anterior cervical spine approach through the space between the visceral sheath and the vascular sheath. Surgical method: Two intervertebral discs with adjacent lesions and part of the vertebrae between them will be removed. A curette will be used to carefully strike off the annulus fibrosus and cartilage on the surface of the adjacent upper and lower endplates. The removed vertebral bone will be trimmed into cancellous bone particles and filled in a cervical titanium cage with an appropriate size. The titanium cage will be implanted into the vertebral space, and fixed with adjacent vertebrae using anterior cervical titanium plates and screws.<br>* Other names: Control group;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Cervical joint range of motion at 6 months after operation | Testing methods for cervical joint mobility include: Cervical joint range of motion in all directions will be accurately obtained through an in vitro infrared measurement after artificial joint replacement (joint range in °). | 6 months after operation | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Cervical fusion rate at 3 to 6 months after operation | A successful fusion is assessed according to Brantigan and Steffee's imaging rating scale: Suspicious bone fusion: bone bridge formation in the entire fusion area with a density at least similar to postoperative data, and no light-transmitting band between the grafted bone and the vertebral body; Strong fusion: the fused bone in the fusion area is more mature and dense as shown on postoperative images. A sclerosis zone between the grafted bone and the vertebral body indicates the fusion, but there is no interface between the grafted bone and the vertebral body, and the mature bone trabecula forms a bone bridge. The bone spurs on the anterior side of the vertebral body will be absorbed, and the bone graft in the intervertebral space will move forward until the facet joints are fused. Fusion rate = (number of successfully fused patients/total number of patients) × 100% (Fusion rate in percentage). | 3 to 6 months after operation | 
| Cervical joint range of motion at 7 days to 3 months after operation | Testing methods for cervical joint mobility include X-ray: The mobility of the cervical spine during flexion and extension, lateral flexion, and rotation; Coda Motion, an internationally advanced joint mobility measuring instrument of the experimental unit, will be used to measure cervical spine mobility; Cervical joint range of motion in all directions will be accurately obtained through an in vitro infrared measurement after artificial joint replacement. | 3 to 6 months after operation | 
| Japanese Orthopaedic Association (JOA) scores at 7 days to 6 months after operation | JOA scoring involves upper limb motor function (4 points), lower limb motor function (4 points), sensation (6 points) and bladder function (3 points). The higher score indicates the better motor function | 7 days to 6 months after operation | 
| Neck Disability Index (NDI) scores at 7 days to 6 months after operation | NDI is mainly used for assessing cervical spine function. The higher score indicates the severer cervical spine dysfunction. | 7 days to 6 months after operation | 
| Visual analogue scale (VAS) scores at 7 days to 6 months after operation | VAS is mainly used for pain assessment. The higher score indicate the severer pain. | 7 days to 6 months after operation | 
| CT images of the cervical spine at 7 days postoperatively | CT images of the cervical spine are used to evaluate the implantation of the artificial cervical joint. | 7 days after operation | 
| X-ray of the cervical spine at 7 days to 6 months after operation | X-ray of the cervical spine is used for evaluating the morphology of the implanted cervical joint morphology. | 7 days to 6 months after operation | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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cervical spondylosis, cervical spine, intervertebral disc, joint replacement