[Efficacy of Hybrid anterior cervical spine surgery on range of motion and curvature in the treatment of cervical degenerative diseases].

OBJECTIVE: To observe the change of cervical curvature and range of motion (ROM) on imaging at 6 months after Hybrid surgery. METHODS: A total of 29 patients with cervical degenerative disease who underwent Hybrid surgery from January 2017 to July 2018 were retrospectively analyzed. Also, they all met the inclusion criteria and had complete preoperative and 6 months postoperative imaging data. There were 11 males and 18 females, aged from 34 to 76 (55.86±10.69) years, and the operation time was from 2 to 4(3.03±0.51) hours. The Cobb angle method was used to measure the changes of cervical curvature and ROM of C2-C7, replacement segments, fusion segments, and upper adjacent segments on cervical lateral X-rays before and 6 months after surgery. RESULTS: There was no statistically significant difference in C2-C7 curvature and ROM between 6 months after operation and before operation (P>0.05). The degree of curvature and ROM of the replacement segment increased compared with that before operation (P<0.05). The curvatureof the fusion segment was increased than that before operation (P<0.05). There was no statistically significant difference in ROM of the fusion segment compared with that before operation (P>0.05). There was no statistically significant difference in the curvature and ROM of the upper adjacent segments compared with those before operation (P>0.05). There was no significant difference in the curvature between the replacement and fusion segments before and 6 months after operation (P>0.05);the ROM of the replacement segment was higher than that of the fusion segment at 6 months after operation (P<0.05). CONCLUSION: Hybrid surgery reconstructs the lordotic curvature of the entire cervical spine and the responsible segment, retains the ROM of the cervical replacement segment, and restores the biomechanical function of cervical spine.

[Clinical observation on the treatment of cervical degenerative diseases with Hybrid surgery].

OBJECTIVE: To investigate the clinical effect of anterior cervical Hybrid surgery in the treatment of cervical degenerative diseases (CDD) and observe the incidence of heterotopic ossification of disc replacement segment at 1 year after surgery. METHODS: From January 2015 to April 2018, 35 patients who received anterior cervical hybrid surgery met the inclusion and exclusion criteria and the complete clinical follow up data were analyzed retrospectively. Complete imaging follow-up data were obtained from 24 patients. There were 15 males and 20 females, aged from 39 to 70(55.57±7.73) years old. The amount of bleeding was for 20 to 100 (40.29±18.39) ml, and the hospitalstay was for 4 to 28(11.03±4.63) days, and the follow-up time was(12.97±1.36) months. Clinical outcomes were assessed by the Tanaka Yasushi cervical spondylitis symptom scale 20 score (YT20), and Japanese Orthopaedic Association (JOA) score. The occurrence of heterotopic ossification after Hybrid surgery was evaluated by X-ray according to McAfee standard one year after operation. Patients with or without heterotopic ossificationwere divided into two groups and their clinical effects were compared. RESULTS: At the final follow up, the mean YT20 score and JOA score were significantly higher than those before operation (P <0.05), and the average improvement rate of JOA was (70.66 ±0.44)%. One year after operation, the heterotopic ossification occurred in 10 of 24 segments, with incidence of 41.70%(10/24), including 29.20% in gradeⅠand 12.50% in gradeⅡ. The results of clinical efficacy comparison between patients with and without heterotopic ossification were as follows:there was no significant difference in JOA score before and after operation (P>0.05);there was no significant difference in YT20 score before operation (P>0.05), and YT20 score in patients with heterotopic ossification was significantly lower than that in patients without heterotopic ossification(P<0.05). CONCLUSION: The short-term clinical effect of Hybrid surgery is satisfactory for cervical degenerative diseases, and the cause of heterotopic ossification still needs tobe further explored.

Effect of Platelet-Rich Plasma Injection on Mild or Moderate Carpal Tunnel Syndrome: An Updated Systematic Review and Meta-Analysis of Randomized Controlled Trials.

OBJECTIVE: To evaluate efficacy of platelet-rich plasma (PRP) injection in carpal tunnel syndrome (CTS), we conducted this meta-analysis, as well as proposed a protocol for its application in curative processes. METHODS: All randomized controlled trials (RCTs) of PRP for the management of mild or moderate CTS were included in this study. Database search was conducted from study inception to July 2020, including PubMed, Embase, Web of Science, and Cochrane Library. We used visual analogue scores (VAS) and the Boston Carpal Tunnel Questionnaire (BCTQ) as evaluation tools for primary outcomes. Second outcomes comprised cross-sectional area (ΔCSA) and electrophysiological indexes including distal motor latency (DML), sensory peak latency (SPL), motor nerve conduction velocity (MNCV), sensory nerve conduction velocity (SNCV), compound muscle action potential (CMAP), and sensory nerve action potential (SNAP). The pooled data were analyzed using RevMan 5.3. Subgroup and sensitivity analyses were conducted with the evidence of heterogeneity. Egger' test was used to investigate publication bias. RESULTS: 9 RCTs were finally screened out with 434 patients included. Control groups comprised corticosteroid injection in 5 trials, saline injection in 1 trial, and splint in 3 trials. At the 1st month after follow-up, only ΔCSA between the PRP group and the control group showed significant difference (P < 0.05). In the 3rd month, there were statistically significant differences in VAS, BCTQ, SPL, SNCV, and ΔCSA between two groups (P < 0.05), while no statistically significant differences were found in the remaining outcomes. In the 6th month, there were statistically significant differences at BCTQ (P < 0.05) in primary outcomes and ΔCSA (P < 0.05) in secondary outcomes between two groups. As to adverse events in PRP injection, only one study reported increased pain sensation within 48 h after injections. CONCLUSION: This systematic review and meta-analysis demonstrates that the PRP could be effective for mild to moderate CTS and superior to traditional conservative treatments in improving pain and function and reducing the swelling of the median nerve for a mid-long-term effect. To some extent, the electrophysiological indexes also improved after PRP injection compared with others conservative treatments.

Long-Term Clinical Outcomes of Percutaneous Cervical Nucleoplasty for Cervical Degenerative Diseases with Neck Pain and Cervical Vertigo.

BACKGROUND: Good short- and mid-term clinical efficacy of percutaneous cervical nucleoplasty (PCN) for cervical degenerative diseases (CDD) with neck pain has been reported. However, few studies have assessed its long-term influence in patients with both neck pain and cervical vertigo. This study aimed to evaluate the curative efficacy of PCN for CDD with neck pain and cervical vertigo with minimum of 6 years of follow-up. METHODS: Inpatients who underwent PCN for CDD with neck pain and cervical vertigo between April 2010 and March 2013 were enrolled. Clinical outcomes were assessed using the Cervical Vertigo Evaluation Scale (CVES); greater CVES scores reflected less impairment. Additional open surgeries were recorded. RESULTS: Among 40 patients, 100% completed the 1-year short-term and 3-year mid-term follow-up (FU); 85% completed the 6-year long-term FU. Clinical effective rates were 67.5%, 67.5%, and 52.94% at short-, mid-, and long-term FU, respectively. CVES scores were greater than the preoperative CVES scores at all FU timepoints (P < 0.01). However, the CVES score was lower at the final FU than at the 3-year FU (P < 0.05). The neck pain score significantly decreased over time and was lower than the cervical vertigo score at the final FU (P > 0.05). Reoperation rates were 1/40 (2.50%) and 3/34 (8.82%) at mid- and long-term FU, respectively. CONCLUSIONS: PCN in patients with CDD neck pain and cervical vertigo showed satisfactory clinical efficacy at short- and mid-term FU, and it was fair at long-term FU. Thus, PCN could be a complementary operation for CDD.

Micro-architecture study of the normal odontoid with micro-computed tomography.

Introduction: Odontoid fractures easily lead to instability, causing spinal cord injury. The aim of this study was to measure and analyze the micro-architecture and morphometric parameters of the normal odontoid with high-resolution three-dimensional (3D) micro-computed tomography (micro-CT).Methods: Micro-CT scans were obtained from five normal odontoid processes. The scanned data were reconstructed with micro-CT software, and the nutrient foramina and the ossification center of the base of the odontoid were revealed. The trabeculae of the odontoid were measured and divided into four parts to obtain the volume fraction of regions of interest.Results: High-resolution 3D images of the micro-structures' parameters were obtained from the odontoid using micro-CT software. The images demonstrated sponge-like trabecular bone, with the trabeculae showing a complex, net-like micro-construction. The subchondral bone plate was of lamella-like, compact construction and extended and transformed into a net-like structure with rod-shaped trabeculae arranged radially in all directions. There was a statistically significant difference in the volume fraction compared with the region of interest in the fourth part of the trabeculae and the first part of the odontoid (P < 0.05). The nutrient foramina and the ossification center of the odontoid were also observed.Conclusions: It is feasible to use high-resolution 3D micro-CT to evaluate the micro-architecture of the normal odontoid. Other studies can benefit from use of the micro-CT images, such as finite element evaluations.

Effects of decompression joint Governor Vessel electro-acupuncture on rats with acute upper cervical spinal cord injury.

Decompression is the major therapeutic strategy for acute spinal cord injury, but there is some debate about the time window for decompression following spinal cord injury. An important goal and challenge in the treatment of spinal cord injury is inhibiting or reversing secondary injury. Governor Vessel electroacupuncture can improve symptoms of spinal cord injury by inhibiting cell apoptosis and improving the microenvironment of the injured spinal cord. In this study, Governor Vessel electroacupuncture combined with decompression at different time points was used to treat acute spinal cord injury. The rat models were established by inserting a balloon catheter into the atlanto-occipital space. The upper cervical spinal cord was compressed for 12 or 48 hours prior to decompression. Electroacupuncture was conducted at the acupoints Dazhui (GV14) and Baihui (GV 20) (2 Hz, 15 minutes) once a day for 14 consecutive days. Compared with decompression alone, hind limb motor function recovery was superior after decompression for 12 and 48 hours combined with electroacupuncture. However, the recovery of motor function was not significantly different at 14 days after treatment in rats receiving decompression for 12 hours. Platelet-activating factor levels and caspase-9 protein expression were significantly reduced in rats receiving electroacupuncture compared with decompression alone. These findings indicate that compared with decompression alone, Governor Vessel electroacupuncture combined with delayed decompression (48 hours) is more effective in the treatment of upper cervical spinal cord injury. Governor Vessel electroacupuncture combined with early decompression (12 hours) can accelerate the recovery of nerve movement in rats with upper cervical spinal cord injury. Nevertheless, further studies are necessary to confirm whether it is possible to obtain additional benefit compared with early decompression alone.

Incidence and risk factors for adjacent segment degeneration following occipitoaxial fusion for atlantoaxial instability in non-rheumatoid arthritis.

PURPOSE: To investigate the incidence and risk factors for adjacent segment degeneration (ASD) following occipitoaxial fusion (OAF) for atlantoaxial instability (AAI) in non-rheumatoid arthritis (RA). METHODS: The study group comprised 41 patients without RA who underwent OAF due to AAI. Fifteen patients with postoperative ASD after OAF were classified as the ASD group, and the other 26 patients without postoperative ASD were included in the non-ASD group. There were 12 men and 3 women with a mean age of 43.52 years in the ASD group, and 19 men and 7 women with a mean age of 45.31 years in the non-ASD group. The mean follow-up period was 6.1 and 5.9 years in the ASD group and non-ASD group, respectively. Clinical outcomes and plain radiographs were retrospectively reviewed and compared between the two groups. RESULTS: The difference between pre- and postoperative O-C2 angles in the non-ASD group was significantly greater than that in the ASD group. The C2-7 angles changed significantly between the pre- and postoperative periods. It was suggested that the small O-C2 angle and large C2-7 angle observed in the early postoperative period were risk factors for the development of ASD. We also demonstrated a high incidence of subaxial subluxation (SAS) and swan neck deformity in the ASD group (27 versus 3.8% and 20 versus 0%, respectively). CONCLUSION: Under-correction of the O-C2 angle is likely to cause malalignment of the cervical spine, resulting in the development of postoperative ASD, SAS, and swan neck deformity.

[Effect of Buyanghuanwu decoction on the expression of platelet activating factor after acute spinal cord injury in rats].

OBJECTIVE: To investigate the effect and mechanism of Buyanghuanwu decoction on platelet activating factor expression in spinal cord tissue of model of acute upper cervical spinal cord injury in rats. METHODS: Sixty SPF grade 3-month-old female Wistar rats were randomly divided into sham operation group, model group, methylprednisolone group and Buyanghuanwu decoction (Traditional Chinese Medicine group, TCM), with 15 rats in each group. The first day after the modeling, the methylprednisolone group were treated by injection of the tail vein for a total of 24 h, the first dose of 30 mg/kg, followed by a dose of 5.4 mg/kg·h, and 1 time per 4 h. The traditional Chinese medicine group was prepared with a medium dose of Buyanghuanwu decoction granules which were prepared into a solution containing 2 g/ml of granules, 3.5 g/kg per day gavage, was equivalent to 1 time the amount of adult consumption. The model group and the sham operation group were given equal volume of normal saline for 2 times a day for 2 weeks. The recovery of nerve function was evaluated by BBB classification at 1, 3, 7, 14 days after treatment. The expression of PAF in the segment of spinal cord injury was detected by double antibody sandwich (ELISA) method at 1, 7, and 14 d postoperatively. RESULTS: At the first day after treatment, BBB score in model, TCM and methylprednisolone groups were lower than that of sham operation group(P<0.01), but there was no difference among the three groups(P>0.05). At 7, 14 days afer treatment, BBB score in TCM and methylprednisolone groups were higher than that of model group significantly(P<0.01); but there were no significant difference between TCM group and methylprednisolone group(P>0.05). PAF expression in TCM group and methylprednisolone group were lower than that of model group at 7, 14 day afer treatment significantly (P<0.05); but there were no significant difference between TCM group and methylprednisolone group (P>0.05). CONCLUSIONS: Buyanghuanwu decoction treatment after acute upper cervical spinal cord injury can significantly improve locomotor recovery by inhibiting the expression of PAF.

[Clinical study on spinal cord decompression combined with traditional Chinese medicine for the treatment of cervical spondylotic myelopathy].

OBJECTIVE: To compare the clinical effect between spinal card decompression combined with traditional Chinese medicine and simple spinal card decompression for cervical spondylotic myelopathy. METHODS: From June 2012 to June 2015, 73 patients with cervical spondylotic myelopathy were treated, including 42 males and 31 females, aged from 29 to 73 years old with a mean of 50.9 years old. The patients were divided into the simple operation group (34 cases) and the operation combined with traditional Chinese medicine group(39 cases) according to the idea of themselves. The anterior discectomy or subtotal corpectomy with internal fixation or posterior simple open-door decompression with lateral mass screw fixation were performed in the patients. Among them, 39 cases were treated with traditional Chinese medicine after surgery. The Japanese orthopedic association (JOA) score of spinal cord function, the improvement rate of neural function, the neck dysfunction index (NDI) score and the governor vessel stasis syndrome score were compared between two groups preoperative and postoperative 1 week, 1 month and the final follow-up respectively. The internal fixation and the condition of spinal cord decompression were observed by CT, MRI and X-rays before and after operation. RESULTS: All the operations were successful, no injuries such as dura mater, spinal cord and nerve root were found. All the wounds were healed without infection except one patient had a superficial infection. It was solved after intermittent debridement and anti-infective therapy. Hematoma occurred in 1 case, complicated with spinal cord compression, caused incomplete paralysis, and promptly performed the re-operation to remove the hematoma without any obvious sequelae. All the patients were followed up from 12 to 24 months, (14.6±0.8) months for simple operation group and (13.5±0.7) months for operation combined with traditional Chinese medicine group, and there was no significant difference(P>0.05). The scores of JOA, NDI and the governor's vessel stasis syndrome in simple operation group were 8.31±3.15, 29.91±4.52, 6.58±1.31 before operation, and 10.21±2.58, 18.67±4.31, 8.24±1.18 one week after operation, and 11.38±2.85, 16.11±3.18, 8.91±2.11 one month after operation, and 12.21±3.12, 14.61±3.28, 9.12±1.56 at final follow-up, respectively; and in operation combined with traditional Chinese medicine group were 8.29±3.47, 30.83±4.14, 6.38±1.81before operation, and 10.48±2.39, 17.59±5.14, 8.33±1.57 one week after operation, and 12.14±3.12, 13.14±3.21, 9.55±2.49 one month after operation, and 13.85±3.34, 12.11±2.51, 10.33±1.95 at final follow-up, respectively. Postoperative JOA , NDI, and the governor vessel stasis syndrome score of two groups were significantly higher than preoperativee(P<0.05). There was no significant difference in JOA, NDI, and the governor vessel stasis syndrome score between two groups one week after operation (P>0.05). The above items in operation combined with traditional Chinese medicine group was better than that of simple operation group one month and final follow-up after operation (P<0.05). The improvement rate of neural function in simple operation group was (67.59±10.78)%, and in operation combined traditional Chinese medicine group was (66.88±12.15)%, there was no significant difference between two groups(P>0.05). There were no complications such as internal fixation failure or re-dislocation of atlas by postoperative CT, MRI and X-rays examination. CONCLUSIONS: Spinal card decompression for the treatment of cervical spondylotic myelopathy can extend the spinal canal, relieve the compression of nerve, achieve the deoppilation of governor vessel, the regulation of qi and blood, the restore of Yangqi, combined with traditional Chinese medicine of activating blood removing stasis, warming yang and activating meridians, reinforcing liver benefiting kidney, which may obtain better clinical effect.

[Effects of decompression combined with electro-acupuncture on rat with acute severe upper cervical spinal cord compression injury].

OBJECTIVE: To explore the effect and underlying mechanism of decompression(DE)combined with Governor Vessel(GV)electro-acupuncture(EA) on rats with acute severe upper cervical spinal cord compression injury. METHODS: Thirty SPF rats were randomly divided into 5 groups(control group A, B and experiment group C, D, E), 6 rats in each group. The model of acute severe upper cervical spinal cord compression injury were made by forcing a balloon catheter put in atlas pillow clearance. The group A was blank one, the group B put balloon catheter in atlas pillow clearance without forcing, and the group C, D, E sustained compressed for 48 h. The group C received electric acupuncture intervention, selecting the Baihui and Dazhui point, having the continuous wave and frequency of 2 Hz, with the treatment time of 15 min and continuous treatment for 14 d; the group D received methylprednisolone intervention, injected by caudal vein; the group E did not received any intervention again. The arterial blood and injured spinal cord tissue of all the rats were obtained after 14 days' treatment, and BBB score was used to evaluate the change of each group hind limbs motor function, the contents of platelet activating factor(PAF) in injured spinal cord tissue and blood serum were assess by ELISA method; the Caspase-9 expression for each group after 14 days' treatment was assess by Western blot method. RESULTS: BBB scores were(21.000±0.000) points at the 6 time points, that was, 1 h, 48 h after forcing in control group, 24 h, 3 d, 7 d, 14 d after treating in experiment group; the score of experimental groups (group C, D, E) were always lower than control groups(group A, B); compared with group E, group C and D were significantly higher(P<0.05); and there was no significant difference between group C and group D(P>0.05). The results of PAF by ELISA method to measure:the concentration of serum PAF, there was no statistical difference among group A, B, D, E (P>0.05), group C was lower than the other groups (P<0.05); the concentration of tissue PAF, there was no significant difference between group A and group B(P>0.05), group D was significantly higher than that of group A, B, and C(P<0.05), group E was the highest one than that of the other groups(P<0.05). Western blot med tests showed that the Caspase-9 protein expression in group A and B was similar (P>0.05), group C was higher than that of group A and B(P<0.05), group D was higher than group A, B and C(P<0.05), group E was the highest than that of group A, B, C and D (P<0.05). CONCLUSIONS: Decompression and Governor Vessel electro-acupuncture on acute severe upper cervical spinal cord compression injury had a better effect compare with decompression and methylprednisolone or simple decompression only, its mechanism may be related to lower the PAF levels and downregulating Caspase-9 protein expression in spinal injury tissue.

Is Anatomic Reduction Better Than Partial Reduction in Patients with Vertical Atlantoaxial Dislocation?

OBJECTIVE: To describe lower cranial nerve (CN) palsy following vertical overdistraction when performing occipitocervical fusion (OCF) to treat vertical atlantoaxial dislocation (AAD) and basilar invagination (BI) and investigate its possible causes. METHODS: We report 4 cases with vertical AAD and BI who presented postoperatively with neurogenic dysphagia, dysarthria, and bucking after undergoing anatomic reduction. RESULTS: Patients underwent revision surgery to achieve partial reduction and demonstrated remarkable recovery of CN IX, X, and XI deficits. CONCLUSIONS: Performing OCF in the overdistraction position to treat vertical AAD may caudally displace the brainstem relative to the cranial base, resulting in traction injury to the CN IX, X, and XI where they exit the skull base through the jugular foramen.

Posterior decompression and occipitocervical fixation followed by intraoperative vertebroplasty for metastatic involvement of the axis.

BACKGROUND: Metastases to the upper cervical spine were rarely reported in the literature. However, metastases to this area may cause spinal instability and cord compression, which in turn can result in respiratory failure and neurological dysfunction. The present study investigated the efficacy and safety of posterior decompression and occipitocervical fixation followed by intraoperative vertebroplasty for this disease. METHODS: This was a retrospective study that included 10 patients with metastatic involvement of the axis from March 2002 to May 2014. All cases presented with occipitocervical pain: 5 patients with compressive myelopathy and 6 patients with radiculopathy. Japanese Orthopedic Association (JOA) scores and Visual Analogue Scale (VAS) were used to evaluate the improvement of neurological function and pain intensity, respectively. RESULTS: All patients underwent posterior decompression and occipitocervical fixation followed by intraoperative vertebroplasty. The VAS scores and JOA scores both improved postoperatively, from 8.2 ± 0.4 to 2.3 ± 0.2 and from 10.1 ± 2.2 to 14.2 ± 2.9, respectively. Additionally, the improvement rate of JOA was 52.4 ± 1.8%. The mean overall survival was 12.8 months. The median survival time was 7 months. The 6-month and 12-month survival rates were 70% and 40%, respectively. The mean duration of operation was 182 min and blood loss was 450 mL. The mean volume of bone cement injected was 4.0 mL. The cement extravasation was observed in only 1 patient without clinical symptoms. One patient developed tumour recurrence and died 1 month later. CONCLUSIONS: Posterior decompression and occipitocervical fixation followed by intraoperative vertebroplasty was a safe and valuable palliative method with relatively less invasion to treat metastatic involvement of the axis.

Spinal Metastasis Resulting from Atypical Thymic Carcinoid: A Case Report.

BACKGROUND: Thymic carcinoid with spinal metastasis is an extremely rare entity. Clinically, the tumor presents either by its endocrine manifestations or by mechanical compression of surrounding structures. However, no previously published case studies have reported neck pain and neurologic deficit in the initial presentation of an atypical thymic carcinoid. CASE DESCRIPTION: A 56-year-old man, a nonsmoker, presented with a 12-month history of intermittent neck pain and a 1-month history of progressive numbness and weakness of the right upper limb. Cervical MRI showed multiple abnormal signals and C2 soft-tissue mass intruding into the vertebral canal. Cervical CT scan showed multiple bone lesions. The diagnosis of thymic carcinoid was obtained by preoperative lymph node biopsy. The patient underwent cervical laminectomy and occipitocervical fixation. Significant alleviation of pain and neurologic improvement were achieved. The postoperative pathological examination confirmed the diagnosis of thymic carcinoid. CONCLUSIONS: Neck pain and neurologic deficit could be the first presentation of thymic carcinoid with spinal metastasis. Palliative surgery is an effective method to improve quality of life in patients with thymic carcinoid with spinal metastasis.

A Modified Personalized Image-Based Drill Guide Template for Atlantoaxial Pedicle Screw Placement: A Clinical Study.

BACKGROUND Atlantoaxial posterior pedicle screw fixation has been widely used for treatment of atlantoaxial instability (AAI). However, precise and safe insertion of atlantoaxial pedicle screws remains challenging. This study presents a modified drill guide template based on a previous template for atlantoaxial pedicle screw placement. MATERIAL AND METHODS Our study included 54 patients (34 males and 20 females) with AAI. All the patients underwent posterior atlantoaxial pedicle screw fixation: 25 patients underwent surgery with the use of a modified drill guide template (template group) and 29 patients underwent surgery via the conventional method (conventional group). In the template group, a modified drill guide template was designed for each patient. The modified drill guide template and intraoperative fluoroscopy were used for surgery in the template group, while only intraoperative fluoroscopy was used in the conventional group. RESULTS Of the 54 patients, 52 (96.3%) completed the follow-up for more than 12 months. The template group had significantly lower intraoperative fluoroscopy frequency (p<0.001) and higher accuracy of screw insertion (p=0.045) than the conventional group. There were no significant differences in surgical duration, intraoperative blood loss, or improvement of neurological function between the 2 groups (p>0.05). CONCLUSIONS Based on the results of this study, it is feasible to use the modified drill guide template for atlantoaxial pedicle screw placement. Using the template can significantly lower the screw malposition rate and the frequency of intraoperative fluoroscopy.