Objective: To explore the correlation of balance ability with short term memory and executive function among college students, so as to provide a theoretical basis for balance training and cognitive enhancement in college students. Methods: In November 2024, 80 college students were recruited from Chongqing Normal University. The dynamic and static balance abilities were measured using the Y-balance test(YBT) and PhysioSensing equipment. Short term memory and executive function were assessed through the digital span test, trail making test(TMT) and Stroop colour-word task. Pearson or Spearman analysis was used to explore the correlation between balance ability and cognitive function among college students. Results: The comprehensive scores of the balance YBT for college students were as follows: left side (95.14±5.93)% and right side (95.17±5.24)%.The average sway velocity of static balance under the conditions of stable surface with eyes open, stable surface with eyes closed, unstable surface with eyes open and unstable surface with eyes closed were 27.58(20.45, 37.64), 23.56(17.57, 34.77), 61.15(40.73, 78.05), 55.88 (40.84, 66.65)mm/s. The comprehensive scores of the YBT for both lower limbs in college students were negatively correlated with the time taken for TMT Part A (TMT-A), TMT Part B (TMT-B), and the difference in time spent between TMT-A and TMT-B (TMT-D) ( r =-0.55 to -0.24，all P <0.05). The average sway velocity under the four conditions was positively correlated with TMT-A, TMT-B, TMT-D, consistent reaction time, conflict reaction time and reaction time difference ( r =0.26-0.69，all P < 0.05). Under conditions of normal vestibular sensation with proprioception interference, the visual contribution in college students was negatively correlated with TMT-A, TMT-B, conflict reaction time and reaction time difference ( r =-0.28 to -0.22,all P < 0.05 ). Under conditions of normal vision and vestibular sensation, the proprioception contribution in college students was positively correlated with TMT-A, TMT-B, consistent reaction time, conflict reaction time and reaction time difference( r =0.26-0.39,all P < 0.05). Under conditions of normal vestibular sensation with visual interference, the proprioception contribution in college students was positively correlated with consistent reaction time and conflict reaction time ( r =0.24, 0.25,both P <0.05). Conclusions There is a correlation between balance ability and executive function in college students. When maintaining static balance, if the visual or proprioceptive system is interfered with, college students with poorer executive function rely more on other systems for compensation.

Objectives:To study the influence on stability and stress of posterior atlantoccipital transarticu-lar-clivus screw(TACL)in occipitocervical fixation using the finite element analysis method.Methods:Finite element models were established using the occipitocervical CT data of a volunteer,including an intact model,an unstable model,and six models of occipitocervical fixations:occipital screw(OS)+C1 lateral mass screw(C1LMS)+C2 pedicle screw(C2PS),OS+atlantoccipital transarticular screw(TA)+C2PS,OS+atlantoccipital transar-ticular-clivus screw(TACL)+C2PS,Occipital condyles screw(OcC)+C1LMS+C2PS,TA+C2PS,and TACL+C2PS.Material parameters were assigned to the models,and a vertical downward force of 40 N was applied to the upper surface of the occipital bone to simulate the weight of head.A torque of 1.5N·m was applied to in-duce flexion,lateral bending,and rotational movements.The stability,implant stress distribution,and bone stress distribution of each occipitocervical fixation model under different conditions were compared.Results:The range of motion(ROM)of the intact model under physiological conditions was similar to those reported in the literatures,and the ROMs under flexion,extension,lateral bending and rotation conditions was 19.53°,17.37°,10.44° and 38.74°,respectively.The ROMs of the unstable model under flexion,extension,lateral bending and rotation conditions were 26.17°,18.90°,10.99° and 42.30°,respectively,which were 34.00％,8.82％,5.34％and 9.20％higher than those of the intact model,respectively.The ROMs of the six fixation models were reduced under the same working conditions.Compared to the unstable model,TACL+C2PS cut 97.43％,94.06％,96.68％,and 99.01％of the ROM under the four working conditions.The peak internal fix-ation stresses were 241.00MPa,241.20MPa,166.94MPa,and 168.80MPa for TACL+C2PS,and 295.00MPa,295.00MPa,73.54MPa,and 81.40MPa for OS+TACL+C2PS in the same working conditions;The internal fixa-tion stresses were concentrated in the middle of the connecting rod and the tail of the TACL,and both mod-els applying the TACL fixation technique had less cutting stress on the bone,which had a more reasonable stress distribution than other occipital fixation techniques.Conclusions:Posterior TACL as a technique for occipital fixation can meet the mechanical strength requirements for occipitocervical fixation and has superior stability and stress distribution compared with other occipital fixation techniques applied alone,and its combined application with posterior occipital screws provides greater mechanical stability.

Objectives:To study the influence on stability and stress of posterior atlantoccipital transarticu-lar-clivus screw(TACL)in occipitocervical fixation using the finite element analysis method.Methods:Finite element models were established using the occipitocervical CT data of a volunteer,including an intact model,an unstable model,and six models of occipitocervical fixations:occipital screw(OS)+C1 lateral mass screw(C1LMS)+C2 pedicle screw(C2PS),OS+atlantoccipital transarticular screw(TA)+C2PS,OS+atlantoccipital transar-ticular-clivus screw(TACL)+C2PS,Occipital condyles screw(OcC)+C1LMS+C2PS,TA+C2PS,and TACL+C2PS.Material parameters were assigned to the models,and a vertical downward force of 40 N was applied to the upper surface of the occipital bone to simulate the weight of head.A torque of 1.5N·m was applied to in-duce flexion,lateral bending,and rotational movements.The stability,implant stress distribution,and bone stress distribution of each occipitocervical fixation model under different conditions were compared.Results:The range of motion(ROM)of the intact model under physiological conditions was similar to those reported in the literatures,and the ROMs under flexion,extension,lateral bending and rotation conditions was 19.53°,17.37°,10.44° and 38.74°,respectively.The ROMs of the unstable model under flexion,extension,lateral bending and rotation conditions were 26.17°,18.90°,10.99° and 42.30°,respectively,which were 34.00％,8.82％,5.34％and 9.20％higher than those of the intact model,respectively.The ROMs of the six fixation models were reduced under the same working conditions.Compared to the unstable model,TACL+C2PS cut 97.43％,94.06％,96.68％,and 99.01％of the ROM under the four working conditions.The peak internal fix-ation stresses were 241.00MPa,241.20MPa,166.94MPa,and 168.80MPa for TACL+C2PS,and 295.00MPa,295.00MPa,73.54MPa,and 81.40MPa for OS+TACL+C2PS in the same working conditions;The internal fixa-tion stresses were concentrated in the middle of the connecting rod and the tail of the TACL,and both mod-els applying the TACL fixation technique had less cutting stress on the bone,which had a more reasonable stress distribution than other occipital fixation techniques.Conclusions:Posterior TACL as a technique for occipital fixation can meet the mechanical strength requirements for occipitocervical fixation and has superior stability and stress distribution compared with other occipital fixation techniques applied alone,and its combined application with posterior occipital screws provides greater mechanical stability.

Objective:To investigate the clinical significance of a new classification system for atlas fractures based on pre- and post-treatment CT features, with a focus on diagnosis and treatment.Methods:A retrospective analysis was conducted on 75 cases of cervical vertebra fractures treated at the Sixth Hospital of Ningbo City between January 2015 and December 2020. The study included 44 males and 31 females, with an average age of 53.3±13.0 years (range: 27-81 years). The fractures were classified according to the Landells classification, resulting in 12 cases of type I, 13 cases of type II, 33 cases of type III, 9 cases that were difficult to classify due to fracture lines located at anatomical junctions, and 8 cases that could not be classified using the Landells classification due to diverse injury mechanisms. To establish a new preliminary classification for cervical vertebra fractures, the researchers considered whether the fracture line in the CT images involved the facet joint surface of the atlas, the impact on bilateral half-rings, and the displacement distance of the fracture ends. Five spinal surgeons were randomly selected to classify the CT images of the 75 patients using the new classification method. After one month, the imaging data of the 75 cases of cervical vertebra fractures were randomized and reclassified to assess the reliability and repeatability of the classification.Results:The new cervical vertebra fracture classification method comprised three types based on whether the fracture line involved the facet joint surface of the atlas: type A (no involvement of the facet joint surface of the atlas), type B (involvement of one side of the facet joint surface with intact contralateral half-ring), and type C (involvement of one side of the facet joint surface with fractured contralateral half-ring). Additionally, based on the maximum displacement distance between the fracture ends (>4 mm), six subtypes were identified: subtype 1 (≤4 mm displacement) and subtype 2 (>4 mm displacement). Consequently, the subtypes were classified as A1, A2, B1, B2, C1, and C2. According to the new classification method, the 75 patients included 17 cases of A1, 12 cases of A2, 7 cases of B1, 13 cases of B2, 12 cases of C1, and 14 cases of C2. The classification demonstrated excellent consistency, as assessed by the five doctors, with Kappa values of 0.85 and 0.91 for reliability and repeatability, respectively. At the final follow-up, all conservatively treated patients achieved bone healing, while four surgically treated patients experienced non-union of the fracture ends but exhibited good fusion between the atlas and axis. The remaining surgically treated patients achieved bony union without complications such as loosening or fracture of internal fixation.Conclusion:The new cervical vertebra fracture classification method, based on CT imaging features, comprehensively covers common clinical cases of cervical vertebra fractures and demonstrates excellent consistency. It provides valuable clinical guidance for the diagnosis and treatment of cervical vertebra fractures.

Objective:To investigate the safety and efficacy of short-segment fixation covering the fractured vertebrae via posterior intermuscular approach plus percutaneous kyphoplasty (PKP) through the outer upper edge of the base of the fractured vertebral pedicle in the treatment of osteoporotic thoracolumbar burst fracture.Methods:A retrospective case series study was used to analyze the clinical data of 56 patients with osteoporotic thoracolumbar burst fracture admitted to Ningbo No.6 Hospital from January 2018 to February 2021, including 24 males and 32 females; aged 56-72 years [(63.5±4.6)years]. All patients underwent short-segment fixation covering the fractured vertebrae via posterior intermuscular approach combined with PKP through the outer upper edge of the base of the fractured vertebral pedicle. The operation time, intraoperative blood loss, hospitalization day and surgery-related complications were recorded. The visual analogue score (VAS) of back pain, ratios of the anterior, middle and posterior height of the fractured vertebrae and kyphotic Cobb angle were compared before operation, at postoperative 2 days and at the final follow-up.Results:All patients were followed up for 12-28 months [(14.5±2.2)months]. The operation time was 55-85 minutes [(62.0±12.1)minutes], intraoperative blood loss was 80-150 ml [(94.0±18.5)ml], and hospitalization day was 5-9 days [(7.4±1.1)days]. Based on CT examination at postoperative 2 days, there were 2 patients with paravertebral cement leakage, 2 with intervertebral space leakage and 1 with intracanal leakage, but none reported associated clinical symptoms. No implant failure or fractures of adjacent segments was detected during the follow-up period. The VAS was significantly decreased from preoperative (7.5±1.2)points to (3.2±0.8)points at postoperative 2 days ( P<0.01), and the score was further lowered to (2.2±0.8)points at the final follow-up when compared with that at postoperative 2 days ( P<0.01). The ratios of the anterior, middle and posterior height of the fractured vertebrae and kyphotic Cobb angle were significantly improved at postoperative 2 days [(89.5±13.2)%, (85.8±7.9)%, (89.5±9.0)% and (5.6±3.2)°] when compared with those before operation [(48.9±11.8)%, (61.9±11.9)%, (79.9±9.8)% and (26.3±5.6)°] (all P<0.01). Slight losses were observed in the ratios of the anterior, middle and posterior height of the fractured vertebrae and kyphotic Cobb angle at the final follow-up [(87.0±12.7)%, (82.1±7.8)%, (88.6±10.0)% and (5.4±3.2)°], but not significantly different from those at postoperative 2 days (all P>0.05). Conclusion:Short-segment fixation covering the fractured vertebrae via posterior intermuscular approach plus PKP through the outer upper edge of the base of the fractured vertebral pedicle can safely and effectively treat osteoporotic thoracolumbar burst fracture, for it can significantly improve back pain, restore the height of the fractured vertebrae and correct the kyphotic deformity.

Objective:To investigate the anatomical safety and feasibility ofposterior occipitocervical fixation with atlan-tooccipital-clivus screw.Methods:Data of 60 patients who treated in the spinal department of our hospital with upper cervical computed tomographic scans from February 2017 to November 2019 were retrospectively collected. Occipitocervical infection, injury, tumor and deformity were excluded. The Mimics software was used to reconstruct the occiput, atlas and measure the anatomical parameters, including the height and width of the anterior edge of the clivus, the height and width of the middle part of the clivus, the thinnest distance of the soft tissue in front of the clivus, the anteroposterior diameter, transverse diameter, the angle of inside tilting in coronary plane of the occipital condyle, the distance from the hypoglossal canal to the atlantooccipital articular surface, the anteroposterior diameter and transverse diameter of the superior joint of atlas, the height of the lateral mass, and the height and transverse diameter of the inferior articular process of the superior atlas joint. The three-dimensional digital modeling was performed and the screw diameter of 3.5mm was simulated. 3-Matic software were used to measure the screw placement parameters, including the inside tilting angle in coronary plane of screw, and the angle of upper tilting in sagittal plane and length of screw. The atlanto-occipital junction was exposed at the rear of 8 cadavers. According to the above parameters, the titanium alloy screws with a diameter of 3.5 mm were transferred from the inferior articular process and posterior arch of the atlas to the clivus through the atlantooccipital. Finally, the screw path was cut along the nail path with a pendulum saw, and the track of the screw was observed to confirm the safety and effectiveness of the screw.Results:The leading edge height and width of male clivus was 16.8±2.5 mm and 20.1±3.1 mm. The middle part of the clivus was 9.7±2.3 mm and 22.4±3.7 mm. The thinnest soft tissue in front of the clivus was 5.8±1.48 mm. The anteroposterior diameter of the occipital condyle was 19.1±1.9 mm, the transverse diameter was 12.6±2.0 mm, the inside tilting angle was 33.7°±4.5°, and the vertical distance from the lowest point of the neural tube to the articular surface of the occipital condyle was 9.6±1.1 mm. The height of the lateral mass of atlas was 12.9±2.4 mm, the anteroposterior diameter of the upper joint of atlas was 21.7±1.9 mm, and the transverse diameter was 11.7±1.4 mm. The width of the inferior facet was 14.9±1.4 mm and the height of the inferior facet was 5.7±0.85 mm. The distance from the screw entry point to the vertical line of the lateral mass migration midpoint was 2.5±0.6 mm; The distance from the screw entry point to the horizontal line of the midpoint was 2.3±0.7 mm.The inside titling angle of screw was 18.4°±1.6°, the upper tilting angle was 55.6°±3.1°, the length of the screw track was 53.0±2.8 mm, the adjustment range of upper tilting angle was 15.0±2.8 mm, the adjustment range of inside tilting angle was 10.4±2.4 mm. The anatomical parameters of females were slightly smaller than those of males, and the difference was statistically significant, but there was no significant difference between left and right parameters. The screws of 8 specimens could be inserted safely and effectively.Conclusion:Atlan-tooccipital-clivus screw can be implanted without damaging the nerve and vascular structure, and it can be used as a choice for occipitocervical fixation.

Objective:To investigate the safety of posterior atlantoaxial transarticular screw combined with atlas pedicle screw fixation in Chinese.Methods:CT data of upper cervical spine in 48 patients were collected from Ningbo No.6 Hospital, including 26 males and 22 females aged 26-58 years [(37.3±13.5)years]. All CT data was transformed into 3D dimensional model and inserted with virtual screws by Mimics 19.0. Firstly, the vertical plane P 1 and the horizontal plane P 2 of the atlas were built in those atlantoaxial models, secondly the atlantoaxial transarticular screw S 0 was inserted by Margel method, and it's insertion point was located at 3 mm lateral and 2 mm cephalad in the C 2 inferior articular process. Finally, four atlas pedicle screws were inserted at the midline of atlas lateral mass. The four screws are inserted as follows. S 1: the screw was tangent to the lateral side of the S 0 or the medial of the atlas pedicle. S 2: the screw was tangent to the lateral wall of the atlas pedicle. S 3: the screw was tangent to the upper wall of the atlas pedicle. S 4: the screw was tangent to the inferior wall of the atlas pedicle. The angles between S 1, S 2 and P 1 as the camber angle, and the angle between S 3, S 4 and P 2 as the gantry angle were measured. Then the safety range of camber angle and gantry angle were calculated, and the screw length of S 1, S 2, S 3 and S 4 was measured. In all models, the camber angle and gantry angle of the screws were adjusted an interval of 2°, the number of successful cases was calculated and the success rate of insertion was calculated. Results:All 3D models were inserted successfully. The minimum value, maximum value and safety range of the camber angle of atlas pedicle screws were (-6.7±5.2)°, (10.4± 4.3)°, (17.1±3.7)°, respectively; and of the gantry angle were (-0.5±3.5)°, (11.0±5.8)°, (11.5±4.9)°, respectively. The length of screw placement was S 1: (31.1±2.4)mm, S 2: (28.3±2.5)mm, S 3: (29.2±3.8)mm, S 4: (29.6±3.0)mm, respectively ( P<0.05). When the camber angle was from -1°to 5°, the success rate of screw placement was 87.5%; when inserting with 2° camber angle, the success rate was 100%; when the gantry angle was 5°, the success rate was 93.8%. Conclusion:The posterior atlantoaxial transarticular screw combined with atlas pedicle screw can achieve satisfy insertion length and success rate.

Objective: To compare the clinical efficacy of posterior atlantoaxial screw-rod fixation combined with spinous process muscle-vessel complex bone graft or iliac bone graft for atlantoaxial instability. Methods: A retrospective case-control study was conducted to analyze the clinical data of 56 patients with atlantoaxial instability admitted to the Sixth Hospital of Ningbo from September 2014 to October 2016. There were 35 males and 21 females, with the age range from 9 to 59 years [(50.3±3.2)years]. A total of 26 patients were treated with posterior atlantoaxial screw-rod fixation combined with spinous process muscle-vessel complex bone graft (complex group), while 30 patients were treated with iliac bone graft (ilium group). Patients showed different degrees of neck pain and limited neck activity preoperatively. X-ray films and three-dimensional CT examination of the cervical spine were taken before and after operation for evaluating the atlantoaxial reduction, bone graft fusion and internal fixation. The operation time, intraoperative bleeding, bone fusion time, visual analogue scale (VAS), Japanese Orthopaedic Association (JOA) score, atlantodental interval (ADI) and axial symptoms were compared between the two groups, and the complications were recorded. Results: Both groups were followed up for 24-30 months, with an average of 27.4 months. In the complex group and the ilium group, the operation time was (2.21±0.25)hours and (2.72±0.26)hours (P<0.01); the intraoperative blood loss was (227.3±45.4)ml and (277.7±43.4)ml, respectively (P<0.05); the bone fusion time was (6.9±0.5)months and (8.1±1.8)months (P>0.05), respectively. In the complex group, the VAS was (5.45±0.69)points before operation, (2.64±0.51)points at the follow-up one month after operation, (0.91±0.7)points at the follow-up 12 months after operation, and (0.45±0.16)points at the follow-up 24 months after operation; and in the ilium group, the VAS was (5.18±0.75)points, (2.45±0.52)points, (1.27±0.19)points and (0.41±0.18)points correspondingly. In terms of VAS, there were significant differences before and after operation within each group (P<0.01), while there were no significant differences between the two groups at different time points (P>0.05). In the complex group, the JOA score was (10.82±0.35)points before operation, (12.73±0.65)points at the follow-up one month after operation, (15.18±0.61)points at the follow-up 12 months after operation, and (15.64±0.15)points at the follow-up 24 months after operation; and in the ilium group, the JOA score was (10.73±1.19)points, (13.01±0.63)points, (14.73±0.91)points and (15.55±0.51)points correspondingly. In terms of JOA score, there were significant differences between before and after operation within each group (P<0.01), while there were no significant differences between the two groups at different time points (P>0.05). In the complex group, the ADI was (2.28±0.59)mm before operation, (1.83±0.56)mm at the follow-up one month after operation, (1.71±0.56)mm at the follow-up 12 months after operation, and (1.59±0.67)mm at the follow-up 24 months after operation; and in the ilium group, the ADI was (2.23±0.60)mm, (1.80±0.18)mm, (1.67±0.69)mm and (1.62±0.53)mm correspondingly. In terms of ADI, there were significant differences between before and after operation within each group (P<0.01), while there were no significant differences between the two groups at different time points (P>0.05). The axial symptom scores were graded as excellent in 23 patients and good in three patients of the complex group while excellent in 21 patients and good in nine patients in the ilium group (P>0.05). There were no patients with spinal nerve injury caused by pedicle screw placement after operation. One patient in the ilium group had incision errhysis and recovered after dressing change, and other patients had no incision infection. Conclusions For atlantoaxial instability, posterior atlantoaxial screw-rod fixation combined with spinous process muscle-vessel complex bone graft or autogenous iliac bone graft can both achieve satisfactory clinical results. The spinous process-muscle-vascellum complex graft has less operation time and intraoperative bleeding than the autogenous iliac bone graft, which can be a feasible alternative operation.

Objective: To investigate the accuracy and feasibility of individual 3D printing model for pedicle screw placement in treating patients with upper cervical spine fracture. Methods: A retrospective case control study was conducted to analyze the clinical data of 30 patients with upper cervical spine fracture admitted to Ningbo No.6 Hospital from August 2013 to December 2018. There were 19 males and 11 females, aged 45-67 years with an average age of 53.5 years. The 15 patients in the study group were treated with pedicle screw fixation and another 15 patients in the control group were treated with traditional freehand screw fixation. A total of 120 pedicle screws were implanted, with 60 screws in each group. The operation time, intraoperative blood loss, preoperative and postoperative visual analogue score (VAS), Japan Orthopedic Association (JOA) score were recorded. The position and grade of screws were evaluated according to Kawaguchi's evaluation method of screw grade after operation. The patients took monthly reexamination for the first three months after discharge. In the first two months after discharge, the patients took X-ray examination for observation of screw loosening or rupture of internal fixation. At the third month after operation, the patients took CT of cervical spine for observation of bone healing and fusion. Results: The mean follow-up duration was 17.8 months (range, 13-21 months). The study group had shorter operation time (99.13±3.04)minutes compared with the control group (107.00±6.92) minutes (P<0.01). There were no significant differences in intraoperative blood loss, preoperative VAS, JOA scores before operation and 1 year after operation between the two groups (P>0.05), but the VAS in study group was significantly lower than that in control group (P<0.05). In the study group, the VAS score 1 year after operation [(2.3±0.5)points] was lower than that before the operation [(7.7±0.7)points], and the JOA score [(16.8±0.4)points] was significantly higher than that before the operation [(15.9±0.7)points](P<0.01). In the control group, the VAS 1 year after operation [(2.5±0.5)points] was significantly lower than that before operation [(7.5±0.5)points] (P<0.01), and the JOA score [(16.5±0.5)points] was significantly higher than that before operation [(15.9±0.8)points] (P<0.05). In the study group, according to the CT results, there were 28 atlas pedicle screws of grade 0 (93.3%), two of grade 1 (6.7%), 0 of grade 2, 0 of grade 3, and there were 27 axial pedicle screws of grade 0 (90.0%), three of grade 1 (10.0%), 0 of grade 2, and 0 of grade 3. In the control group, there were 25 atlas pedicle screws of grade 0 (83.3%), four of grade 1 (13.3%), one of grade 2 (3.4%), 0 of grade 3, and there were 27 axial pedical screws of grade 0 (90.0%), three of grade 1 (10.0%), 0 of grade 2, and 0 of grade 3. There was no significant difference in the accuracy of pedicle screw placement between the two groups (P>0.05). No serious complications such as spinal cord or vertebral artery injury occurred. At 3 months after operation, CT showed that the fracture of cervical vertebra healed. Conclusion Individualized 3D printed cervical spine model can guide the pedicle screw placement for upper cervical spine fracture, which can shorten the operation time, reduce the postoperative pain of patients, improve the accuracy of screw placement, and reduce the risks related to operation.

Objective: To investigate the efficacy of microscope-assisted free-hand atlantal pedicle screw technique for unstable atlas burst fracture. Methods: A retrospective case control study was conducted to analyze the clinical data of 48 patients with unstable atlas burst fracture admitted to Ningbo No.6 hospital from January 2016 to June 2018. There were 32 males and 16 females, aged 24-72 years [(49.5±15.2 years)]. A total of 22 patients were treated with the technique of atlas screw placement by drill under microscope (Group A), including 14 males and eight females, aged 24-68 years. Twenty six patients (Group B) were treated with atlantal pedicle screw placement by hand, including 18 males and 8 females, aged 26-72 years [(50.7±15.4 years)]. The operation time, intraoperative blood loss and the times of intraoperative fluoroscopy were compared between the two groups. X-ray and CT were reexamined to evaluate the accuracy of screw placement within one week after operation. The visual analogue score (VAS) and cervical dysfunction index (NDI) were compared before operation and 1 year after operation. The intraoperative complications were recorded. One year after operation, X-ray and CT were reexamined to observe fracture healing, atlantoaxial fusion and failure of internal fixation. Results: Group A was followed up for 12-24 months [(18.4±6.8)months], and Group B for 12-24 months [(17.4±7.2)months]. The amount of intraoperative bleeding [(180.5±60.8) ml] and the times of intraoperative fluoroscopy [(1.3±0.8) times] in Group A were significantly lower than those in Group B [(280.1±80.2) ml, (2.2±0.8) times] (P<0.05), but there was no significant difference in the time of operation and the accuracy of screw placement (P>0.05). There were statistically significant differences in VAS and NDI before operation and one year after operation in both groups (P<0.05), but there was no significant difference between the two groups (P>0.05). No serious complications such as vertebral artery, nerve root and spinal cord injury occurred. One year follow-up CT showed healed fracture or continuous bone bridge passing through the atlantoaxial intervertebral space. Except for one patient in Group B with lost reduction, other patients had no loosening or fracture of internal fixation. Conclusion Compared with screw placement by hand, the pedicle screw placement by drill under the microscope can reduce the amount of bleeding and the times of fluoroscopy.