A retrospective analysis was performed on 70 patients diagnosed with CSR and underwent cervical spine surgery. From January 2015 to December 2016, 412 cases of cervical spine surgery performed by an experienced doctor (Xiaojian Ye) were collected and stored in the Changzheng Hospital Orthopedic Medical Database. According to the following inclusion and exclusion criteria, 70 patients diagnosed with single-segment CSR were treated with PEPCD or ACDF. medical history and physical examination, NDI and VAS (neck and upper limb) score, cervical X-ray, MRI and CT were used to determine the clinical outcome. All patients were scheduled for follow-up at 3, 6, and 12 month and after each year postoperatively through an outpatient or telephone consultation.
The inclusion criteria for this study were: (1) older than 20 years old. (2) a clear diagnosis of single-segment CSR, and at least 8 weeks of strict conservative treatment is invalid. (3) The surgical segment is a single segment in C2-T1 and is operated by ACDF or PEPCD.
The exclusion criteria for this study: (1) Existence of cervical surgery contraindications. (2) Having surgery, trauma, infection, or cancer history of neck. (3) Multi-segmental CSR. (4) Cervical spondylotic myelopathy, extensive post-toughening with ossification, or simple axis of the neck pain without nerve root symptoms. (5) Patients who can not tolerate general anesthesia or surgery.
Under general anesthesia, the patient is supine in the operating bed, and the neck is in the extended position to increase the intervertebral height of the target segment. Use C arm machine for positioning. In the right side of the neck skin for a length of about 3 cm transverse incision, and layer by layer exposed to the target intervertebral space. Removal of the intervertebral discs and the compression of the spinal cord and nerve roots, including prominent nucleus pulposus, osteophyte and posterior longitudinal ligament. Scrape the cartilage lamina, but to protect the bone plate to prevent the sedimentation of the implant. Preoperative evaluation and intraoperative measurement to select the appropriate size of the Zero-P (Johnsonn). Zero-P was filled with autogenous bone or artificial bone, and then use Zero-P's own screws to fix. Rinse the surgical area, stop bleeding, rinse again, and then sutured the incision layer by layer. Complete surgery. After the operation, the patients were treated with dehydrating agents and neurotrophic drugs. The second day after surgery under the protection of the neck support to get out of bed activities, and neck support needs to wear 2-4 w.
PCPED was performed using the TESSYS TM system (Joimax, Germany). The patients were placed in the prone position on a customized plaster bed, and the neck was slightly buckled to increase the intervertebral space size of the target segment and reduce the overlap of small joints under general anesthesia. Double upper limbs close to the trunk, fingers toward the tail, the patient's head and double upper lip with a fixed with tape (figure.1 A). Use C arm machine for auxiliary positioning. Two 20 G long positioning needles were punctured at about 1.5-2 cm on the outside of the spinous process of the target gap (figure.1 B), and locate the needle at the K point by fluoroscopy (K point: the focal point of the upper lamina, the lower lamina and the connection of the medial margin of the adjacent facet figure.1D). A longitudinal skin incision with a length of about 0.8mm is positioned at the positioning needle, and the guide needle is inserted into K point, and the expansion sleeve is gradually arranged until the work channel. When the channel is in a good position (figure.1C), take out the guide wire and the expansion sleeve, and put into the intervertebral disc endoscope. 0.9% of the saline hanging in the top of the patient about 1.5 m, adjust the flow rate about 50-100 ml / min, connected to the endoscopic device for continuous lavage. Radiofrequency ablation and hemostasis under endoscope. The lower edge of the upper lamina and the upper edge were removed by grinding and laminectomy (3mm of the medial margin of the facet joint). The range of bite is within 1/3 of the articular process (Figure.1D，Figure.2 A-D). Using the blue tweezers to remove some of the ligamentum flavum, the epidural venous plexus was coagulated by bipolar radiofrequency electrode to maintain a clear visual field and accurately identify nerve roots. According to the imaging data of the patients, the decision was made to expand the intervertebral foramen or remove the nucleus pulposus. When the intervertebral foramen stenosis, you can use the bite forceps and power grinding (Stryker, USA) to expand the intervertebral foramen. Decompression was performed until proximal and distal pedicles were confirmed longitudinally, a probe was then easily inserted through the foramen to confirm adequate neural decompression. When the disc is prominent, using nerve root probe to explore the nerve root axillary and nerve root shoulders, to determine the location of the nucleus pulposus; use nucleus pulposus gradually remove the prominent nucleus until the nerve root completely released (Figure.2 C-E). The fiber ring and the soft tissue around it were ablated by radio frequency electrode. When the dura mater beat was good, the decompression was complete. Use radio frequency to stop bleeding, rinse the area, take out the intervertebral foramen mirror and channel, suture the incision and complete the operation (Figure.2 F). Because of the small incision of the PEPCD, it is not necessary to have a drainage tube after operation, and the silica gel can be placed for drainage and remove within 24 hours after operation. After the operation, the patients were treated with dehydrating agents and neurotrophic drugs. The second day after surgery under the protection of the neck support to get out of bed activities, and neck support needs to wear 5-7 d.
Figure.1 Position and orientation during operation. A: the patient in the prone position on a customized plaster bed; B: Two positioning pins used to determine the target gap and K point; C: The cervical spine radiograph shows that the expansion sleeve is located near the K point of the gap; D: Three dimensional CT display of K point and the range of intraoperative laminectomy.
Figure.2 Intraoperative visual field and postoperative incision. A: Dynamic grinding system for removal of lamina; B: Vertebral lamina and ligament were removed by the biting forceps; C: Nerve root probe to detect nerve root canal and nerve root; D：Removal of herniated intervertebral disc tissue; E: The prominent nucleus pulposus was removed during operation; F: Postoperative incision.
Intraoperative outcome Measure
According to the patient data and operation records, the operative segment, operation time, amount of bleeding, complications, LOHS (length of hospital stay), and time to return to normal work of the two groups were recorded and compared.
Postoperative outcome evaluation
The NDI, neck and arm VAS score, X-ray, MRI and CT were evaluated on the day before surgery and 3 m, 6 m, 12 m, 24 m, 36 m, 48 m, 60 m and the last follow-up after surgery. The Cobb angle of cervical was measured by C2-7 lordosis (Figure.4 B) , and DHI was measured by Emery . According to the modified Pfirrmann classification, the degree of cervical disc degeneration was evaluated before and after operation . According to the preoperative and the last follow-up of the cervical dynamic X-ray film to determine whether the existence of cervical instability: intervertebral angle> 10°or displacement> 3 mm to determine intervertebral instability.
Mean outcome scores for NDI, neck and arm VAS were compared for each follow-up period. Statistical analysis was conducted with the Student t-test, with P<0.05 considered significant.