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 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 compare the efficacy of O-arm navigation-assisted and conventional posterior cervical expansive open-door laminoplasty (CEOL) via the intermuscular approach in the treatment of cervical spinal cord injury without fracture-dislocation (CSCIWFD).Methods:A prospective cohort study was conducted to analyze the clinical data of 60 CSCIWFD patients who were admitted to Zhengzhou Orthopedic Hospital from May 2021 to May 2023, with compression at C3-C6. Patients were randomly divided into two groups: 30 patients underwent O-arm navigation-assisted intermuscular approach CEOL (navigation-assisted group) and 30 patients underwent conventional intermuscular approach CEOL (conventional surgery group). Surgical duration, intraoperative blood loss, postoperative drainage volume, and total surgical blood loss were compared between the two groups. At 2 weeks postoperatively, CT scan was performed to evaluate the accuracy of hinge or open-door position preparation of the surgical segments. Visual analogue scale (VAS) for neck and shoulder pain and Japanese Orthopedic Association (JOA) scores were compared between the two groups preoperatively, at 2 weeks, 6 months postoperatively, and at the last follow-up. Complication rates were also evaluated.Results:A total of 60 patients with CSCIWFD were included, comprising 35 males and 25 females, aged 35-77 years [(50.9±8.6)years]. All the patients were followed up for 12-24 months [(16.9±3.1)months]. The surgical duration and intraoperative blood loss were (121.6±17.9)minutes and (144.7±44.2)ml in the navigation-assisted group, shorter or less than (132.3±14.6)minutes and (178.7±48.7)ml in the conventional surgery group ( P<0.05). There were no statistically significant differences in postoperative drainage volume and total surgical blood loss between the two groups ( P>0.05). CT scan reviewed at 2 weeks postoperatively revealed that the accuracy rate of hinge and open-door position preparation of the surgical segments in the navigation-assisted group was 99.2% (119/120), significantly higher than 86.7% (104/120) in the conventional surgery group ( P<0.01). Before operation and at 2 weeks, 6 months postoperatively, and at the last follow-up, the VAS scores for neck and shoulder pain and JOA scores in the navigation-assisted group were 5.0(4.0, 7.0)points and (8.7±2.8)points, 3.0(2.0, 4.0)points and (10.2±2.5)points, 2.0(1.0, 2.0)points and (1 3.0±1.8)points, and 1.0(1.0, 2.0)points and (13.9±1.5)points respectively, while in the conventional surgery group, the VAS scores and JOA scores were 5.5(5.0, 6.3)points and (8.8±2.6)points, 4.0(3.0, 4.0)points and (10.4±2.5)points, 2.0(1.0, 3.0)points and (12.9±2.2)points, and 2.0(1.0, 2.0)points and (13.8±2.0)points ( P>0.05). Both groups showed improvement in neck and shoulder VAS scores and JOA scores at 2 weeks, 6 months postoperatively, and at the last follow-up, compared to preoperative scores ( P<0.05); further improvement was observed at 6 months postoperatively and at the last follow-up compared to that at 2 weeks postoperatively ( P<0.05). There were no significant differences between neck and shoulder VAS scores or JOA scores at 6 months postoperatively and at the last follow-up ( P>0.05). In the navigation-assisted group, 2 patients had axial neck-shoulder pain postoperatively, with a complication rate of 7% (2/30); while in the conventional surgery group, 7 patients had axial neck-shoulder pain and one patient developed cerebrospinal fluid leakage and low-pressure headache, with a complication rate of 27% (8/30) ( P<0.05). Conclusion:Compared to the conventional intermuscular approach, O-arm navigation-assisted intermuscular approach CEOL for CSCIWFD reduces surgical duration and intraoperative blood loss, improves the accuracy of hinge and open-door position preparation, and lowers complication rates.

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: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 investigate the feasibility and clinical efficacy of percutaneous vertebroplasty (PVP) with measured saturated bone cement injection in the treatment of elderly patients with stage Ⅱ Kümmell's disease.Methods:A retrospective analysis was conducted to analyze the clinical data of the 41 elderly patients with stage Ⅱ Kümmell's disease who had been treated at Department of Spinal Orthopedics, Zhengzhou Orthopedic Hospital from June 2017 to June 2023 by PVP with bone cement injection into the intravertebral vacuum cleft. According to the amount of bone cement injected, the patients were divided into a saturated volume group (bone cement injection metered ≥ 150% of the cleft volume preoperatively measured) in which there were 21 cases, 4 males and 17 females, aged (78.4±5.2) years and a conventional volume group (bone cement injection metered was 100% to 120% of the cleft volume preoperatively measured) in which there were 20 cases, 6 males and 14 females, aged (79.5±7.4) years. The operative time, vacuum cleft volume measured, actual volume of bone cement injected, and percentage of bone cement injected were compared between the 2 groups. Visual analogue scale (VAS) for pain and Oswestry disability index (ODI) were compared between preoperation, postoperative 3 days, and the final follow-up in the 2 groups, as well as between the 2 groups. Cement leakage and other complications were documented.Results:The differences in the preoperative general data were not statistically significant between the 2 groups, indicating comparability ( P>0.05). All the 41 elderly patients successfully completed their surgery. Follow-up time was (18.1±3.3) months. The operative time [(39.7±7.5) min], actual volume of bone cement injected [(5.6±0.9) mL], and percentage of bone cement injected (1.8%±0.3%) in the saturated volume group were all significantly greater than those in the conventional volume group [(35.5±4.9) min, (4.4±1.0) mL, and 1.2%±0.1%] ( P<0.05). Postoperatively, the incisions healed completely in all patients, with no such complications as cement-related adverse reactions. Cement leakage occurred in 2 patients in the conventional volume group, leading to lumbar pain or discomfort after activity, which was relieved by cement reinforcement and nail-rod internal fixation. VAS pain scores and ODIs at 3 d postoperatively and at the final follow-up were significantly improved in all patients compared with preoperation ( P<0.05). At the final follow-up, both VAS pain score and ODI in the saturated volume group improved significantly greater than those in the conventional volume group ( P<0.05). None of the patients had complications like cement displacement at the final follow-up. Conclusion:PVP with measured saturated bone cement injection into the intravertebral vacuum clefts is a safe and effective treatment for stage Ⅱ Kümmell's disease in elderly patients, offering a new minimally invasive option.

Objective:To screen inflammatory markers that can be used for the diagnosis and intervention evaluation of patients with chronic kidney disease(CKD)with depression,and to systematically study the therapeutic effect and safety of modified Chaihu Longgu Muli decoction in patients with CKD with depression.Methods:This study was a prospective study,a total of 120 patients with CKD who were diagnosed and treated in the Department of Nephrology,Chongqing Traditional Chinese Medicine Hospital from April 2023 to October 2024 were included.They were divided into CKD with depression(CKD-D)group and CKD without depression(CKD-N)group according to the diagnostic criteria by random number table method.The results of routine laboratory tests were collected,and the severity of depressive disorder was evaluated by Hamilton Depression Rating Scale-17(HAMD-17).The levels of interleukin-18(IL-18),interferon-γ(IFN-γ),β-thromboglobulin(β-TG),platlet factor-4(PF-4),eosinophil chemotactic factor(Eotaxin),soluble tumor necrosis factor receptor-2(sTNFR-2)and CD40 ligand(CD40L)in serum were quantitatively evaluated by liquid chip technology.Pearson correlation analysis was used to analyze the correlation between HAMD-17 scores and inflammatory markers with statistical differences in CKD patients with depression at different stages.The patients in CKD-D group were randomly divided into control group and treatment group.The control group was given basic treatment of CKD,while the treatment group was treated with modified Chaihu Longgu Muli decoction on the basis of the control group.After 8 weeks of continuous intervention,the clinical effective rate,the changes of effective inflammatory markers and the occurrence of adverse reactions were compared between the two groups.Results:In the CKD-D group and the CKD-N group,the difference of HAMD-17 score,serum phosphorus(P),serum creatinine(Scr),estimated glomerular filtration rate(eGFR),albumin(ALB),serum iron(Fe3+),C-reactive protein(CRP),IL-18,IFN-γ,sTNFR-2 indicators were statistically significant(P＜0.05).Multivariate Logistic regression analysis showed that in addition to HAMD-17 score(OR=1.259,P=0.006),SCr(OR=1.748,P=0.003),eGFR(OR=1.354,P=0.005),serum IL-18(OR=0.924,P=0.011)and IFN-γ(OR=0.859,P=0.031)levels were also independent influencing factors for CKD patients with depression.Pearson correlation analysis showed that there was a significant positive correlation between HAMD-17 score and IL-18,IFN-γ,sTNFR-2 and CD40L.The total clinical effective rate of the treatment group was higher than that of the control group,and the serum levels of IL-18 and IFN-γ in the treatment group were lower than those in the control group,the differences were statistically significant(P＜0.05),and no significant difference in the incidence of adverse reactions between the two groups(P＞0.05).Conclusion:IL-18 and IFN-γ can be used as effective serum markers for the diagnosis and treatment of depressive disorders in CKD patients.At the same time,the changes of serum levels of IL-18 and IFN-γ can be used to evaluate the severity of symptoms in CKD patients with depression at different stages to a certain extent.Modified Chaihu Longgu Muli decoction may improve CKD combined with depressive symptoms and improve the quality of life of patients by down-regulating the level of inflammatory factors.

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 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.

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.