Occipitocervical fusion with "U" rod and segmental wire fixation

"U"-shaped rods and segmental wire-fixed occipitocervical fusion for the treatment of odontoid deformities. A odontoid deformity is a rare congenital malformation, including odontogenic dysplasia, odontoid distal bone, odontoid separation, and odontoid absence. The odontoid deformity is fixed only to the atlantoaxial joint by local ligamentous tissue, which makes the local instability, and it is easy to cause spinal cord injury due to dislocation caused by trauma. Clinically, it can be asymptomatic, but when it is slightly traumatized, symptoms of medullary or upper cervical spinal cord compression may occur. Reports in the literature are mostly affected by adolescents, manifested by decreased muscle strength, ataxia, pain in the lower part of the pillow and neck, torticollis, muscle tension, and limited mobility. Some may be progressive numbness of the limbs, and severe cases of quadriplegia and death. Most of the treatments advocate active surgery. For unintentional examinations, it is controversial whether or not to prevent the instability of the odontoid before and after the astigmatism is less than 5 mm, because the neck activity of the sick child is difficult to be accepted by the sick child and parents. The pros and cons of surgical and non-surgical treatment should be clearly explained before making a decision on whether or not to perform preventive fusion. For those with pain in the neck, the neck support can be fixed first. If no improvement is made, the atlantoaxial fusion is performed. For patients with unstable cervical spine and radiculopathy, occipitocervical fusion is feasible. For the cervical spinal cord compression, the posterior or posterior atlantoaxial laminectomy is performed, the occipital foramen is enlarged, and the fibrous band is removed to relieve the oppression of the cerebellum, the medulla and the upper cervical spinal cord, and then the occipitocervical fusion is performed. When the odontoid deformity is combined with the absence of the C1 posterior arch, atlantoaxial fusion cannot be performed, and the fusion range should extend to the occipital bone. There are many methods of occipital fusion. Robinson and Southwick's method is to pass each wire under the C1 and C2 lamina, which is more dangerous. In recent years, Wertheim and other scholars have used a modified posterior occipitocervical fusion to form a bone hole on the outer surface of the occipital protuberance through a dental drill. The steel wire only passes through the external skull plate. Because the skull is thicker, it is allowed to wear only the steel wire. Through the outer skull plate, the risk of injury to the superior sagittal sinus is significantly reduced. Koop et al. introduced a occipital and neck arthrodesis in children who did not require internal fixation. After the cortical bone was removed from the cortex, the autologous cortical-cancellous humerus was placed at the site to be fused. For children with vertebral arch defects, the occipital periosteum is folded back to the bone defect to provide a layer of osteogenic tissue for the graft. Postoperatively fixed with HALO plaster. In recent years, there has also been a occipitocervical fusion with a "U" shaped rod and a segmental wire. This procedure has the advantage of early stability of the occipital and neck joints. This method allows the patient to have neck support after surgery and avoids HALO braking. Treatment of diseases: odontoid malformation Indication "U" shaped rods and segmental wire fixed occipitocervical fusion are suitable for: 1. The odontoid deformity causes neurological symptoms. 2. The dentate process is unstable and shifts forward or backward by more than 5 mm. 3. The dentate process is unstable and persistently aggravated. 4. The neck is persistently discomfort due to instability of the atlantoaxial axis and is not relieved by conservative treatment. 5. The posterior arch of the atlas is incomplete and is not suitable for atlantoaxial fusion. Contraindications Patients with no clinical symptoms should be closely observed to avoid trauma, and can be fixed with a neck collar. Preoperative preparation 1. X-ray of lateral position and open position of the neck, showing odontoid deformity, CT examination showed odontoid deformity type. 2. MRI examination to understand the compression of the cervical spinal cord and nerve roots, further excluding syringomyelia, cervical spinal cord or cerebellar tumor. 3. Patients with neurological symptoms should first perform skull traction for 1 to 2 weeks, make it reset, restore nerve function, reduce cervical spinal irritation, and then consider surgery. 4. Bed bed training and prone position training. 5. Prefabricated one of the back and ventral plaster beds, the length from the top of the head to the middle of the double thighs. 6. 1st preoperative 1d neck 2 spinous process positioning, help to determine the location of the spinous process during surgery, and determine the appropriate line of force from the cervical lateral radiograph. Surgical procedure General anesthesia, endotracheal intubation. The sick child is placed in a prone position, and the head is placed on a special rotatable head frame or on a head support for cerebellar surgery to perform skull traction to ensure that the cervical vertebra is stabilized and then operated. Incision and exposure The longitudinal midline incision was taken to reveal the occipital basal and superior cervical spine processes, which were separated deep in the relatively avascular muscle interval, and the entire surgical field was exposed under the periosteum. The proximal end was separated from the occipital bulge and the lateral side was separated from the occipital. The sides of the bulge are horizontal. 2. Place the "U" shaped rod and fix it Make a Luque "U" shaped rod of appropriate length according to the scope of the fusion. Two holes were drilled on each side of the occipital foramen 2.5 cm and the midline side 2 cm. Care should be taken to avoid the transverse sinus and the sigmoid sinus when drilling. At least 10 mm of intact cortical bone should be left between the two holes on each side to ensure reliable fixation. Then, through the epidural plane between the two holes on both sides of the midline, wear the Luque wire and then thread the wire under the lamina of the upper cervical vertebra. The "U" shaped rod is pre-bent into the desired shape using a pressure bar instrument, typically maintaining a head and neck angle of about 135°, with a mild cervical lordosis, and the wire is securely attached to the "U" shaped rod. 3. Bone fusion After the lamina and occipital bone were removed from the cortex, the autologous cancellous bone was taken for transplantation. 4. Close the incision Wash with saline, suture each layer of the incision layer by layer, and place a vacuum suction tube.

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