ObjectiveThe widespread adoption of portable fundus cameras for primary care and community screening is hindered by limitations in current autofocus(AF) technologies. Image-based methods relying on sharpness evaluation require iterative searches, resulting in slow convergence, while projection-based techniques are susceptible to optical artifacts and calibration errors. To address these challenges, this study introduces a novel AF system based on direct wavefront sensing, designed to deliver simultaneous high speed, high precision, and operational robustness within the compact form factor essential for portable ophthalmic devices. MethodsOur approach fundamentally reimagines the AF process by directly measuring the ocular wavefront aberration. We developed a custom portable fundus camera integrating a miniaturized Shack-Hartmann wavefront sensor (SHWS) into the optical path. An 850 nm laser diode projects a point source onto the retina via oblique illumination to minimize corneal reflections. Light scattered from this spot carries the eye’s refractive error through the imaging optics and is directed to the SHWS, positioned at a plane optically conjugate to the primary color CMOS imaging sensor. A microlens array within the SHWS samples the incident wavefront, generating a pattern of focal spots on a CCD. Real-time centroid analysis of these spots provides a map of local wavefront slopes. These measurements are processed through a singular value decomposition (SVD) algorithm to fit a Zernike polynomial basis set, enabling real-time reconstruction of the wavefront phase. The defocus component (S) is extracted from the second-order Zernike coefficients, providing a direct, quantitative measure of the refractive error in diopters. This value serves as a precise error signal in a closed-loop control system, which commands a voice-coil actuated focusing lens to its null position in a single, deterministic step, eliminating the need for iterative search algorithms. ResultsComprehensive evaluation demonstrated the system’s high performance. Testing on a calibrated model eye (OEMI-7) established a highly linear relationship between the computed defocus S and the focusing lens position across a ±20 Diopter (D) compensation range, achievable within a 5 mm mechanical travel. The system achieved a focusing precision of 0.08 D, corresponding to an 18-fold improvement over a conventional projection spot-size method tested under identical conditions. The total focus acquisition time, encompassing wavefront measurement, computation, and lens actuation, averaged under 0.5 s. Clinical validation with 25 human volunteers (50 eyes, refractive range -15 D to +10 D) confirmed practical efficacy. The wavefront-sensing AF succeeded in 92% of attempts with a mean time of 0.5 s, substantially outperforming a projection-based benchmark which achieved only a 32% success rate with an average time of 4.25 s. The system provided instantaneous directional guidance and maintained stability during minor ocular movements. Objective assessment of image quality, via amplitude contrast of retinal vasculature, showed consistent and significant enhancement following AF correction across the entire tested diopter range. ConclusionThis work successfully implements and validates a direct wavefront-sensing autofocus paradigm for portable fundus cameras. By directly quantifying and compensating for the optical defocus aberration, this method bypasses the fundamental limitations of image-processing and projection-based techniques, enabling rapid, precise, and deterministic diopter compensation. The developed system delivers an exceptional combination of a wide operational range (±20 D), high accuracy (0.08 D), fast convergence (0.5 s), and a compact physical footprint. This technology provides a practical and high-performance focusing solution capable of enhancing the reliability, throughput, and diagnostic utility of portable retinal imaging in large-scale screening applications. Future efforts will be directed towards system cost optimization and performance adaptation for diverse ocular conditions.

Objective： The aim of this study is to explore the predictive value of biparametric magnetic resonance imaging(bpMRI)for pelvic lymph node metastasis in prostate cancer patients with PSA≤20 μg/L and establish a nomogram. Methods： The imaging data and clinical data of 363 patients undergoing radical prostatectomy and pelvic lymph node dissection in the First Affiliated Hospital of Nanjing Medical University from July 2018 to December 2023 were retrospectively analyzed. Univariate analysis and multivariate logistic regression were used to screen independent risk factors for pelvic lymph node metastasis in prostate cancer, and a nomogram of the clinical prediction model was established. Calibration curves were drawn to evaluate the accuracy of the model. Results： Multivariate logistic regression analysis showed extrocapusular extension (OR=8.08,95%CI=2.62－24.97, P<0.01), enlargement of pelvic lymph nodes (OR=4.45,95%CI=1.16－17.11,P=0.030), and biopsy ISUP grade(OR=1.97,95%CI=1.12－3.46, P=0.018)were independent risk factors for pelvic lymph node metastasis. The C-index of the prediction model was 0.834, which indicated that the model had a good prediction ability. The actual value of the model calibration curve and the prediction probability of the model fitted well, indicating that the model had a good accuracy. Further analysis of DCA curve showed that the model had good clinical application value when the risk threshold ranged from 0.05 to 0.70.Conclusion： For prostate cancer patients with PSA≤20 μg/L, bpMRI has a good predictive value for the pelvic lymph node metastasis of prostate cancer with extrocapusular extension, enlargement of pelvic lymph nodes and ISUP grade≥4.
Humans ; Male ; Prostatic Neoplasms/diagnostic imaging* ; Lymphatic Metastasis ; Retrospective Studies ; Nomograms ; Prostate-Specific Antigen/blood* ; Lymph Nodes/pathology* ; Pelvis ; Predictive Value of Tests ; Prostatectomy ; Lymph Node Excision ; Risk Factors ; Magnetic Resonance Imaging ; Logistic Models ; Middle Aged ; Aged

OBJECTIVE: To elucidate how spinal manipulative therapy (SMT) exerts its analgesic effects through regulating brain function in lumbar disc herniation (LDH) patients by utilizing resting-state functional magnetic resonance imaging (rs-fMRI). METHODS: From September 2021 to September 2023, we enrolled LDH patients (LDH group, n=31) and age- and sex-matched healthy controls (HCs, n=28). LDH group underwent rs-fMRI at 2 distinct time points (TPs): prior to the initiation of SMT (TP1) and subsequent to the completion of the SMT sessions (TP2). SMT was administered once every other day for 30 min per session, totally 14 treatment sessions over a span of 4 weeks. HCs did not receive SMT treatment and underwent only one fMRI scan. Additionally, participants in LDH group completed clinical questionnaires on pain using the Visual Analog Scale (VAS) and the Japanese Orthopedic Association (JOA) score, whereas HCs did not undergo clinical scale assessments. The effects on the brain were jointly characterized using the amplitude of low-frequency fluctuations (ALFF) and regional homogeneity (ReHo). Correlation analyses were conducted between specific brain regions and clinical scales. RESULTS: Following SMT treatment, pain symptoms in LDH patients were notably alleviated and accompanied by evident activation of effects in the brain. In comparison to TP1, TP2 exhibited the most significant increase in ALFF values for Temporal_Sup_R and the most notable decrease in ALFF values for Paracentral_Lobule_L (voxelwise P<0.005; clusters >30; FDR correction). Additionally, the most substantial enhancement in ReHo values was observed for the Cuneus_R, while the most prominent reduction was noted for the Olfactory_R (voxelwise P<0.005; clusters >30; FDR correction). Moreover, a comparative analysis revealed that, in contrast to HCs, LDH patients at TP1 exhibited the most significant increase in ALFF values for Temporal_Pole_Sup_L and the most notable decrease in ALFF values for Frontal_Mid_L (voxelwise P<0.005; clusters >30; FDR correction). Furthermore, the most significant enhancement in ReHo values was observed for Postcentral_L, while the most prominent reduction was identified for ParaHippocampal_L (voxelwise P<0.005; clusters >30; FDR correction). Notably, correlation analysis with clinical scales revealed a robust positive correlation between the Cuneus_R score and the rate of change in the VAS score (r=0.9333, P<0.0001). CONCLUSIONS Long-term chronic lower back pain in patients with LDH manifests significant activation of the "AUN-DMN-S1-SAN" neural circuitry. The visual network, represented by the Cuneus_R, is highly likely to be a key brain network in which the analgesic efficacy of SMT becomes effective in treating LDH patients. (Trial registration No. NCT06277739).
Humans ; Magnetic Resonance Imaging ; Intervertebral Disc Displacement/diagnostic imaging* ; Male ; Female ; Brain/diagnostic imaging* ; Adult ; Manipulation, Spinal/methods* ; Middle Aged ; Lumbar Vertebrae/physiopathology* ; Pain Management ; Rest ; Case-Control Studies

OBJECTIVE: To investigate the clinical effect of minimally invasive technique in the treatment of moderate and severe gluteal muscle contracture. METHODS: A retrospective study was conducted on 85 patients (170 sides) with bilateral gluteal muscle contracture admitted from January 2016 to December 2019. All patients were treated with minimally invasive release of tendon knife. There were 32 males and 53 females, ranging in age from 15 to 37 years old, with an average age of (22.3±6.3) years old. Operation time, intraoperative blood loss, incision length, first postoperative ambulation time, complication rate, recurrence rate, and Harris hip score (HHS) were analyzed and evaluated. RESULTS: The average follow-up time was (16.2±4.6) months, ranging from 12 to 30 months. The operation time ranged from 7 to 15 min, with an average of (10.2±3.1) min. Intraoperative blood loss ranged from 2 to 20 ml, with an average of (8.4±2.2) ml. The incision length ranged from 0.6 to 2.0 cm, with an average of (0.8±0.3) cm. The time to postoperative ambulation ranged from 12 to 28 h, with an average of (20.0±3.2) h. All patients achieved primary wound healing without sciatic nerve injury or recurrence. HHS hip function scores ranged from 90 to 98, with an average score of (96.2±1.4). Complications included intraoperative tendon blade tip fracture in two cases (removed under fluoroscopic guidance) and subcutaneous hematoma in three cases-two resolved with compression and one with open evacuation.. Twenty-nine patients exhibited transient swaying gait postoperatively, of which 24 patients returned to normal after 4 weeks and 5 patients returned to normal after 6 weeks. CONCLUSION Minimally invasive tendon blade release is a safe and effective technique for treating gluteal muscle contracture, offering minimal trauma, rapid recovery, and excellent cosmetic and functional outcomes. However, it exhibits a low risk of blade tip fracture and sciatic nerve injury, warranting experienced surgical handling.
Humans ; Male ; Female ; Adult ; Minimally Invasive Surgical Procedures/methods* ; Adolescent ; Retrospective Studies ; Buttocks/surgery* ; Young Adult ; Contracture/surgery* ; Tendons/surgery* ; Muscle, Skeletal/surgery*

Objective:To analyze the clinical efficacy of asymmetric T 1 transpedicular wedge resection Smith-Petersen osteotomy (T 1 SPO) in the treatment of stiff cervical thoracic lateral kyphosis deformity. Methods:This is a retrospective case series study. The clinical data of nine patients with stiff cervical thoracic kyphosis who underwent asymmetric T 1 SPO corrective treatment from June 2012 to October 2022 were collected. There were 7 males and 2 females, aged 45 to 68 years. The surgery time, intraoperative blood loss, and complications were recorded. The chin brow vertical angle (CBVA), cervical thoracic kyphosis Cobb angle, cervical thoracic scoliosis Cobb angle, and cervical thoracic sagittal axis (C 2-T 1 sagittal vertical axis, SVA) before surgery, after surgery, and at the last follow-up were measured and the correction rates were calculate. Results:All 9 patients successfully completed the surgery. The operation time ranged from 245 to 320 minutes, and the intraoperative blood loss was 1 400 to 2 200 ml. All patients were followed up for 24 to 48 months. The preoperative CBVA was 93.7° to 112.0°, which improved to 25.2° to 31.7° at the last follow-up, with an correction rate of 73.4%. The preoperative cervicothoracic kyphosis Cobb angle was -57.0° to -16.6°, which improved to 10.3° to 18.5° at the last follow-up, with an correction rate of 166.7%. The preoperative scoliosis Cobb angle was 13.0° to 16.5°, which improved to 2.2° to 3.8° at the last follow-up, with an correction rate of 84.9%. The preoperative SVA was 7.8 to 12.5 cm, which improved to 4.5 to 6.8 cm at the last follow-up, with an correction rate of 42.3%. One patient experienced numbness and weakness in the left hand after surgery, which recovered after 3 months. One patient had poor healing of the surgical incision, which healed after symptomatic treatment. During the follow-up, the coronal and sagittal balance of all patients was maintained, and no other neurological complications occurred. There were no cases of screw loosening, broken screws, or broken rods, or other internal fixation failures.Conclusion:The application of asymmetric T 1 SPO technique in the treatment of stiff cervical thoracic lateral kyphosis deformity can achieve relatively satisfactory correction effects.

Objective To investigate the correlation between dual-energy computed tomography angiography(CTA)parameters of carotid plaques and acute stroke events.Methods A retrospective analysis was conducted on the clinical and imaging data of patients who underwent dual-energy head and neck CTA and brain MRI scans.Utilizing the Siemens workstation(Syngo.Via VB40B),region of interest(ROI)were placed on the thickest slice of the carotid plaque in the axial plane to obtain parameters such as fat fraction(FF),virtual non-contrast(VNC)value,iodine concentration(IC),electron density(Rho),effective atomic number(Zeff),dual energy index(DEI),spectral curve,and corresponding CT values at 40 keV(40 keVHU)and 90 keV(90 keVHU).The slope of the energy spectrum curve(λ)was calculated within the 40 keV-90 keV range.Patients with acute cerebral infarction(ACI)in the ipsilateral anterior circulation territory were classified into the ACI group,while those without were classified into the non-acute cerebral infarction(NACI)(NACI group).Qualitative data were analyzed using the x2 test,and quantitative data were analyzed using the t-test.The predictive performance was assessed using the area under the curve(AUC)of the receiver operating characteristic(ROC)curve,and the differences between different ROC curves were compared using the DeLong test.Results A total of 72 patients were included,with 21 in the ACI group and 51 in the NACI group.The mean values of FF,Zeff,and 40 keVHU in the ACI group were greater than those in the NACI group.Statistically significant differences were observed between the groups for Zeff,DEI,40 keVHU,and λ(P＜0.05).40 keVHU demonstrated the highest predictive performance,and the AUC,sensitivity,and specificity was 0.789,81.0％,and 74.5％,respectively.A combined variable constructed through logistic regression analysis yielded an AUC,sensitivity,and specificity of 0.796,85.7％,and 70.6％,respectively,with no significant statistical differences compared to single factor variables.Conclusion Dual-energy CTA parameters of carotid plaques may aid in predicting intraplaque hemorrhage(IPH)and the occurrence of acute stroke events.

Objective To construct a clinical-radiological nomo-gram model for severe mycoplasma pneumoniae pneumonia coinfec-tion with other pathogens(Co-SMPP)in children.Methods The clinical and radiological data of children with severe mycoplasma pneumoniae pneumonia(SMPP)who underwent nucleic acid testing or bronchoalveolar lavage(BAL)were analyzed retrospectively.The data analysis were performed by using SPSS 27.0 software.The group comparison between simple SMPP and Co-SMPP children was conducted by using t-tests,Mann-Whitney U tests,or chi-square tests.Nomogram analysis was performed by using R software and rms packages.The predictive performance of the model was evaluated by using the receiver operating characteristic(ROC)curve.Results A total of 194 SMPP children were included in the study,including 136 cases(70.1％)with simple SMPP,58 cases(29.9％)with Co-SMPP.The fibrinogen and albumin levels were lower in Co-SMPP children[(3.53±0.85)g/L,41.00(39.03,43.68)g/L]than in simple SMPP children[(3.79±0.80)g/L,42.80(41.00,44.40)g/L],with P values of 0.047 and 0.036,respec-tively.The probability of bronchial stenosis and grid shadow were higher in Co-SMPP children than in simple SMPP children,and there were significant differences between the two groups(P＜0.001,P=0.010).The odds ratio of bronchial stenosis in predicting Co-SMPP children was 14.085.The clinical-radiological nomogram model had an area under the curve(AUC)of 0.840,with sensi-tivity and specificity of 0.756 and 0.848,respectively.Conclusion The nomogram model based on clinical-radiological features can effectively predict Co-SMPP.

Objective:This study aims to explore the predictive value of the ratio of caliceal pelvic height to infundibular length（CPH/IL）for the stone-free rate（SFR）in the treatment of lower calyx stones using flexible ureteroscopic lithotripsy（FURL）combined with a distally bendable negative pressure suction sheath.Methods:A retrospective analysis was conducted on the clinical data and anatomical parameters of 312 patients with lower calyx stones or combined lower calyx stones admitted to the Third Xiangya Hospital of Central South University from September 2022 to December 2023，all of whom were treated with FURL combined with a distally bendable negative pressure suction sheath. Stone clearance was defined as no residual stones or residual stones with a diameter of ≤3 mm without any symptoms. Patients were divided into the clearance group（265 cases，84.90%）and the non-clearance group（47 cases，15.10%）. There were no significant differences in gender（male/female：173/92 cases vs. 29/18 cases），age［（44.69 ± 13.14）years vs.（42.60 ± 10.93）years］，degree of hydronephrosis（no hydronephrosis/mild hydronephrosis/moderate to severe hydronephrosis：122/85/58 cases vs. 21/12/14 cases），side of lower calyx stones（left/right：157/108 cases vs. 31/16 cases），maximum diameter of stones（MDS）［（19.23 ± 6.41）mm vs.（17.77 ± 6.18）mm］，and CT value of stones［（993.46 ± 249.12）Hu vs.（1013.43 ± 300.90）Hu］between the two groups（ P > 0.05），indicating comparability between groups. There was no significant difference in the distance from the midpoint of the lower lip of the renal pelvis to the ureter at the lowest plane of the lower calyx（K-A line）between the clearance and non-clearance groups［（26.16 ± 5.18）mm vs.（25.70 ± 8.66）mm， P > 0.05］. However，significant differences were observed in the infundibulopelvic angle（IPA）［（53.97 ± 15.72）° vs.（37.43 ± 15.39）°］，infundibular length（IL）［（27.26 ± 5.11）mm vs.（33.04 ± 7.38）mm］，infundibular width（IW）［（8.27 ± 2.82）mm vs.（7.09 ± 3.20）mm］，caliceal pelvic height（CPH）［（19.96 ± 4.63）mm vs.（30.32 ± 7.56）mm］，ureter-lower calyx distance（ULD）［（23.00 ± 5.59）mm vs.（18.78 ± 6.31）mm］，CPH/IL ratio［（0.73 ± 0.11）vs.（0.92 ± 0.09）］，and curvature of the lower calyx of the renal pelvis［（0.06 ± 0.01）mm -1 vs.（0.08 ± 0.03）mm -1］between the two groups（ P <0.05）. Univariate and logistic multivariate regression analyses were used to identify the independent risk factors affecting the postoperative SFR of FURL-treated lower calyx stones and to assess the value of CPH/IL for SFR in the treatment of lower calyx stones using FURL combined with a distally bendable negative pressure suction sheath. A logistic multivariate regression model and a corresponding nomogram were constructed，and the predictive ability of the model for SFR was evaluated using the receiver operating characteristic（ROC）curve. The calibration curve and the Hosmer -Lemeshow test were used to assess the consistency and accuracy of the model. The clinical utility of the model was evaluated using decision curve analysis（DCA）. Results:Univariate analysis revealed that seven anatomical parameters differed significantly between the clearance and non-clearance groups（all P < 0.05）：infundibulopelvic angle（IPA， OR = 0.27，95% CI 0.17-0.42， P < 0.01），infundibular length（IL， OR = 2.52，95% CI 1.83-3.47， P < 0.01），infundibular width（IW， OR = 0.64，95% CI 0.45-0.90， P = 0.011），caliceal pelvic height（CPH， OR = 5.78，95% CI 3.67-9.10， P < 0.01），ureter-lower calyx distance（ULD， OR = 0.43，95% CI 0.30-0.63， P < 0.01），CPH/IL ratio（ OR = 13.62，95% CI 6.86-27.03， P < 0.01），and curvature of the lower calyx of the renal pelvis（ O = 3.15，95% CI 2.08-4.78， P < 0.01）. Multivariate logistic regression further identified CPH/IL（ OR = 9.87，95% CI 4.92-19.79， P < 0.01），IPA（ OR = 0.41，95% CI 0.23-0.71， P = 0.001），and ULD（ OR = 0.50，95% CI 0.29-0.87， P = 0.014）as independent risk factors influencing the stone-free rate after flexible ureteroscopic lithotripsy combined with a distally bendable negative-pressure suction sheath. The area under the ROC curve（AUC）of the univariate regression model showed that for IPA，the AUC was 0.788（95% CI 0.711-0.864）；for IL，it was 0.731（95% CI 0.643-0.819）；for ULD，it was 0.677（95% CI 0.586-0.767）；for CPH，it was 0.867（95% CI 0.804-0.929）；for IW，it was 0.628（95% CI 0.535-0.721）；for CPH/IL，it was 0.906（95% CI 0.850-0.961）with an optimal cutoff value of 0.882，corresponding to a sensitivity of 83.02% and a specificity of 92.08%；and for curvature of the lower calyx of the renal pelvis，it was 0.744（95% CI 0.662-0.827）. The AUC of the multivariate regression model was 0.929（95% CI 0.884-0.974）with an optimal cutoff value of 0.364，corresponding to a sensitivity of 82.98% and a specificity of 95.09%. Calibration curves demonstrated close agreement between the predicted and actual stone-free rates after FURL（C-index = 0.921）. The Hosmer-Lemeshow goodness-of-fit test indicated no significant discrepancy between predicted and observed probabilities（ P = 0.135，>0.05）. Decision-curve analysis further revealed that basing clinical decisions on the model ，s predicted probability yields a higher net clinical benefit than either withholding FURL for all patients or treating all patients regardless of risk，and it also outperforms strategies guided by any single independent predictor alone. Conclusions:IPA，IL，IW，CPH，ULD，CPH/IL ratio，and curvature of the lower calyx of the renal pelvis can all predict the postoperative SFR of FURL combined with a distally bendable negative pressure suction sheath for the treatment of lower calyx stones to varying degrees. Among them，CPH/IL has the highest predictive value. When CPH/IL >0.88，it may be difficult to use FURL to treat lower calyx stones.

Objective:To compare the efficacy of O-arm navigation versus C-arm guidance for anterior internal fixation in the management of Anderson-D′Alonzo type II odontoid fractures.Methods:A retrospective cohort study was conducted to analyze the clinical data of 58 patients with Anderson-D′Alonzo type II odontoid fractures admitted to Zhengzhou Orthopedic Hospital between January 2017 and September 2024, including 35 males and 23 females, aged 18-57 years [(39.3±9.0)years]. Anderson-D′Alonzo type II fractures were further classified as type IIA in 25 patients and type IIB in 33. Twenty-seven patients underwent O-arm assisted anterior internal fixation (O-arm navigation group), while 31 received C-arm guided anterior internal fixation (C-arm guidance group). The two groups were compared in terms of the operative duration, intraoperative blood loss, success rate for one-time guidewire placement, and intraoperative radiation exposure (anteroposterior and lateral views). At 3 days postoperatively, screw placement accuracy was evaluated via CT in both groups. Additionally, neck disability index (NDI) and visual analogue scale (VAS) scores were assessed preoperatively, at 1 week, 3 months postoperatively, and at the last follow-up. Bone union time and complication rate were also analyzed.Results:All the patients were followed up for 6-20 months [(13.1±3.4)months]. The O-arm navigation group exhibited significantly shorter operative duration [(91.1± 8.9)minutes] and less intraoperative blood loss [(38.9±8.2)ml], compared with (103.3±14.5)minutes and (47.3±9.1)ml in the C-arm guidance group ( P<0.01). The success rate for one-time guidewire placement was 100% (27/27) in the O-arm navigation group, significantly higher than 52% (16/31) in the C-arm guidance group ( P<0.01). Intraoperative radiation exposure for patients in the O-arm navigation group was lower in both anteroposterior view [(11 612.6±1 603.6)μSv] and lateral views [(29 738.2±6 602.5)μSv], compared with (40 638.0±9 431.9)μSv and (47 152.0±11 759.3)μSv in the C-arm guidance group ( P<0.01). CT scans at 3 days postoperatively revealed a 100% (27/27) screw placement accuracy in the O-arm navigation group, compared with 65% (20/31) in the C-arm guidance group ( P<0.01). Before operation, at 1 weeks and 3 months postoperatively, and at the last follow-up, NDI scores were (48.4±7.8)%, (21.0±3.1)%, (14.4±2.4)%, and (13.9±2.3)% in the O-arm navigation group, while they were (47.4±7.6)%, (20.9±3.2)%, (14.1±2.0)%, and (13.8±1.4)% in the C-arm guidance group ( P>0.05); VAS scores were 6.0(6.0, 7.0)points, 4.0(3.0, 4.0)points, 2.0(1.0, 2.0)points, and 2.0(1.0, 2.0)points in the O-arm navigation group, while they were 7.0(6.0, 7.0)points, 4.0(3.0, 5.0)points, 2.0(1.0, 3.0)points, and 2.0(2.0, 2.0)points in the C-arm guidance group ( P>0.05). The NDI and VAS scores in both groups were significantly improved at 1 weeks and 3 months postoperatively, and at the last follow-up compared to those preoperatively ( P<0.05), and were furtherly improved at 3 months postoperatively and at the last follow-up compared to those at 1 weeks postoperatively ( P<0.05), with no significant differences between those at 3 months postoperatively and at the last follow-up ( P>0.05). No significant difference was found in bone union time between the two groups ( P>0.05). The complication rate in the O-arm navigation group was 4% (1/27), lower than 29% (9/31) in the C-arm guidance group ( P<0.05). Conclusions:Compared with C-arm guidance, O-arm assisted anterior internal fixation for Anderson-D′Alonzo type II odontoid fractures can reduce operative duration and intraoperative blood loss, improve the success rate for one-time guidewire placement and screw accuracy, and decrease radiation exposure and complication rate.