ObjectiveChronic atrophic gastritis (CAG) is usually diagnosed by gastroscopy and histopathological biopsy. These procedures remain the reference standard, but their invasive nature and resource requirements may limit their use in large-scale population screening and repeated follow-up. A convenient and reproducible method for noninvasive auxiliary screening may help identify individuals who require further endoscopic assessment. Fingertip photoplethysmography (PPG) provides a noninvasive recording of peripheral pulse waves and allows harmonic features to be extracted from the signal. In this study, the so-called meridian-related variables were defined as PPG-derived harmonic parameters labelled according to meridian nomenclature, rather than as direct measurements of meridian physiology. This study aimed to compare these harmonic parameters between patients with CAG and non-CAG controls, identify parameters that remained different after age adjustment, and develop a multivariable model for noninvasive auxiliary screening and pre-endoscopic risk stratification of CAG. MethodsA total of 343 participants were included, comprising 171 patients with CAG and 172 non-CAG controls. CAG diagnosis was established using gastroscopy and histopathology as the reference standard. Fingertip PPG signals were collected using a PPG-based pulse acquisition device. Eight PPG-derived harmonic parameters labelled according to meridian nomenclature were extracted for analysis. Between-group differences were first assessed using nonparametric tests. Age-adjusted analyses were then performed to reduce potential confounding by age. The false discovery rate (FDR) method was applied for multiple-comparison correction. A multivariable logistic regression model integrating age and multiple harmonic parameters was constructed. Model performance was evaluated using receiver operating characteristic (ROC) analysis and the area under the curve (AUC). Internal validation performance was assessed using stratified five-fold cross-validation and bootstrap optimism correction. Threshold performance was examined using both a high-specificity strategy and a Youden index-based cutoff. Decision curve analysis was used to evaluate the model’s net clinical benefit across a range of threshold probabilities. ResultsAll eight harmonic parameters were non-normally distributed. In the univariate analysis, the stomach-labelled harmonic parameter (ST), bladder-labelled harmonic parameter (BL), and liver-labelled harmonic parameter (LR) differed between the CAG and non-CAG groups. After age adjustment and FDR correction, only ST and BL remained statistically significant. Compared with non-CAG controls, patients with CAG showed higher ST values and lower BL values. This finding indicates an associated differential harmonic pattern that was not fully explained by age distribution. However, the discriminative ability of a single harmonic parameter was limited. The best-performing single indicator was ST, with an AUC of 0.652 (95% CI: 0.595-0.707). The multivariable model integrating age and multiple harmonic parameters achieved an AUC of 0.791 (95% CI: 0.743-0.835), representing an improvement of 0.139 over ST alone. In internal validation, stratified five-fold cross-validation yielded a mean AUC of 0.753 (95% CI: 0.715-0.781), and the bootstrap optimism-corrected AUC was 0.748. These results suggest that the model retained moderate discriminative performance after internal validation.At a specificity of at least 95%, the model achieved a sensitivity of only 40.4% (95% CI: 25.7%-49.7%). This high-specificity cutoff may be suboptimal as the preferred threshold for an initial screening setting because of the potential risk of missed CAG cases. The Youden index-based optimal cutoff was 0.419, corresponding to a sensitivity of 80.7% and a specificity of 62.8%. This threshold may better match the practical aim of noninvasive auxiliary screening, where sensitivity is usually prioritized to reduce missed cases. Decision curve analysis showed that, within a threshold probability range of 10%-55%, the model provided higher net clinical benefit than the reference strategies of recommending gastroscopy for all participants or for none. ConclusionPatients with CAG showed associated harmonic differences in fingertip PPG-derived features, mainly characterized by higher ST and lower BL values after age adjustment and FDR correction. Compared with a single harmonic parameter, the multivariable model showed better overall discrimination and retained moderate internal validation performance. These findings suggest that PPG-derived harmonic parameters labelled according to meridian nomenclature may provide auxiliary information for noninvasive auxiliary screening and front-line triage before gastroscopic confirmation in CAG. The present results support further validation rather than immediate clinical implementation. External validation in independent, multicenter, and preferably prospective screening cohorts is needed to assess the model’s generalizability, screening performance, and potential clinical utility.

ObjectiveChronic atrophic gastritis (CAG) is usually diagnosed by gastroscopy and histopathological biopsy. These procedures remain the reference standard, but their invasive nature and resource requirements may limit their use in large-scale population screening and repeated follow-up. A convenient and reproducible method for noninvasive auxiliary screening may help identify individuals who require further endoscopic assessment. Fingertip photoplethysmography (PPG) provides a noninvasive recording of peripheral pulse waves and allows harmonic features to be extracted from the signal. In this study, the so-called meridian-related variables were defined as PPG-derived harmonic parameters labelled according to meridian nomenclature, rather than as direct measurements of meridian physiology. This study aimed to compare these harmonic parameters between patients with CAG and non-CAG controls, identify parameters that remained different after age adjustment, and develop a multivariable model for noninvasive auxiliary screening and pre-endoscopic risk stratification of CAG. MethodsA total of 343 participants were included, comprising 171 patients with CAG and 172 non-CAG controls. CAG diagnosis was established using gastroscopy and histopathology as the reference standard. Fingertip PPG signals were collected using a PPG-based pulse acquisition device. Eight PPG-derived harmonic parameters labelled according to meridian nomenclature were extracted for analysis. Between-group differences were first assessed using nonparametric tests. Age-adjusted analyses were then performed to reduce potential confounding by age. The false discovery rate (FDR) method was applied for multiple-comparison correction. A multivariable logistic regression model integrating age and multiple harmonic parameters was constructed. Model performance was evaluated using receiver operating characteristic (ROC) analysis and the area under the curve (AUC). Internal validation performance was assessed using stratified five-fold cross-validation and bootstrap optimism correction. Threshold performance was examined using both a high-specificity strategy and a Youden index-based cutoff. Decision curve analysis was used to evaluate the model’s net clinical benefit across a range of threshold probabilities. ResultsAll eight harmonic parameters were non-normally distributed. In the univariate analysis, the stomach-labelled harmonic parameter (ST), bladder-labelled harmonic parameter (BL), and liver-labelled harmonic parameter (LR) differed between the CAG and non-CAG groups. After age adjustment and FDR correction, only ST and BL remained statistically significant. Compared with non-CAG controls, patients with CAG showed higher ST values and lower BL values. This finding indicates an associated differential harmonic pattern that was not fully explained by age distribution. However, the discriminative ability of a single harmonic parameter was limited. The best-performing single indicator was ST, with an AUC of 0.652 (95% CI: 0.595-0.707). The multivariable model integrating age and multiple harmonic parameters achieved an AUC of 0.791 (95% CI: 0.743-0.835), representing an improvement of 0.139 over ST alone. In internal validation, stratified five-fold cross-validation yielded a mean AUC of 0.753 (95% CI: 0.715-0.781), and the bootstrap optimism-corrected AUC was 0.748. These results suggest that the model retained moderate discriminative performance after internal validation.At a specificity of at least 95%, the model achieved a sensitivity of only 40.4% (95% CI: 25.7%-49.7%). This high-specificity cutoff may be suboptimal as the preferred threshold for an initial screening setting because of the potential risk of missed CAG cases. The Youden index-based optimal cutoff was 0.419, corresponding to a sensitivity of 80.7% and a specificity of 62.8%. This threshold may better match the practical aim of noninvasive auxiliary screening, where sensitivity is usually prioritized to reduce missed cases. Decision curve analysis showed that, within a threshold probability range of 10%-55%, the model provided higher net clinical benefit than the reference strategies of recommending gastroscopy for all participants or for none. ConclusionPatients with CAG showed associated harmonic differences in fingertip PPG-derived features, mainly characterized by higher ST and lower BL values after age adjustment and FDR correction. Compared with a single harmonic parameter, the multivariable model showed better overall discrimination and retained moderate internal validation performance. These findings suggest that PPG-derived harmonic parameters labelled according to meridian nomenclature may provide auxiliary information for noninvasive auxiliary screening and front-line triage before gastroscopic confirmation in CAG. The present results support further validation rather than immediate clinical implementation. External validation in independent, multicenter, and preferably prospective screening cohorts is needed to assess the model’s generalizability, screening performance, and potential clinical utility.

Three evaluation methods were recommended for the key properties of the intravascular catheter lubricating coating such as stability,lubricity and integrity,including insoluble particle test method,friction test procedure and appearance detection method.Fifteen batches of microcatheters produced by different manufacturers were selected for testing to clarify the three methods in test principle,step,result,characteristic.References were provided for the design,production,evaluation and regulation of intravascular catheters with lubricant coatings.[Chinese Medical Equipment Journal,2025,46(1):66-72]

Objective By observing and measuring the relevant data of the buccal branch of the facial nerve,the parotid duct and the facial artery,the positional relationship among the three was analyzed to avoid accidental injury to the buccal branch of the facial nerve and the parotid duct when ligaturing the facial artery during the operation.Methods Forty adult head and neck specimens were dissected to observe the relationship between the buccal branch of the facial nerve and the parotid duct,the course and positional relationship of the facial artery,and the relationship between the buccal branch of the facial nerve and the peripheral vascular network.The relevant diameters were measured with a vernier caliper.Results The buccal branch of the facial nerve was divided into the superior buccal branch and the inferior buccal branch,and there was no direct anastomosis or connecting fiber between the buccal branch of the facial nerve and the parotid duct.The superior buccal branch was relatively thick,and it has a relatively constant position,which was parallel to the parotid duct.The position of the inferior buccal branch was not constant and it ran on or slightly above the plane of angulus oris.The superior buccal branch was located(10.76±5.54)mm from the parotid duct,while the inferior buccal branch was positioned(6.84±4.06)mm away from the parotid duct.The course of the main trunk of the facial artery was relatively fixed.Moreover,if the branch of the facial artery was missing,other branches of the facial artery would extend to replace the missing branch artery.The main trunk of the facial artery had a diameter of(2.34±0.83)mm,and its branches formed anastomoses with the buccal branch of the maxillary artery,creating a vascular network in the parotid and buccal regions.There was a vascular network around the buccal branch of the facial nerve,which was mostly small branches of the facial artery and the superficial temporal artery.Conclusion The buccal branch of the facial nerve exhibits a consistent anatomic relationship with the parotid duct and the facial artery.During the ligation of the facial artery,the parotid duct can serve as a landmark to accurately locate the buccal branch of the facial nerve,thereby significantly reducing the risk of inadvertent injury to the buccal branch of the facial nerve and the parotid duct.

Objective:To investigate the immuno-inflammatory regulatory effects of the Qing Gan San Jie Xiao Ying Formula(QGSJXYF)on Hashimoto's thyroiditis(HT)by modulating thyroid cell-derived exosomes to provide experi-mental evidence for its immunomodulatory mechanisms.Methods:Nthy-ori-3-1 thyroid cells were treated with QGSJXYF-medicated serum,with untreated cells serving as controls.Exosomes from both groups were extracted and analyzed using nanoparticle tracking analysis(NTA),transmission electron microscopy(TEM),and Western blot to assess concentration,size distribution,morphology,and the expression of characteristic exosomal markers.An inflammatory model of human T lymphocytes(H9)was established and co-incubated with normal exosomes(EXO-C group)or QGSJXYF-treated exosomes(EXO-T group).The levels of inflammatory cytokines in H9 cells were measured using Western blot(WB)and ELISA.Results:Exosome characterization showed that the particle concentration of Nthy-ori-3-1 cell-derived exosomes in both the control and QGSJXYF groups ranged from 1×109 to 1×1011/mL,with particle diameters between 80～300 nm.The exosomes exhibited a typical spherical or cup-shaped morphology with positive expression of TSG101,CD63,and HSP70.Compared with the inflammation model group and the EXO-C group,the EXO-T group significantly reduced the intracellular expression of IL-17A protein in H9 cells(P<0.05)and suppressed IL-17 and IL-6 levels in the cell supernatant(P<0.01).Conclusion:QGSJXYF may exert its anti-inflammatory and thyroid-protective effects by modulating the functional state of thyroid cell-derived exosomes,regulating the inflamma-tory microenvironment,and inhibiting the expression of inflammatory cytokines associated with Hashimoto's thyroiditis.

Objective To investigate the distribution and antimicrobial resistance profiles of clinically isolated Haemophilus influenzae and Moraxella catarrhalis in hospitals across China from 2015 to 2021,and provide evidence for rational use of antimicrobial agents.Methods Data of H.influenzae and M.catarrhalis strains isolated from 2015 to 2021 in CHINET program were collected for analysis,and antimicrobial susceptibility testing was performed by disc diffusion method or automated systems according to the uniform protocol of CHINET.The results were interpreted according to the CLSI breakpoints in 2022.Beta-lactamases was detected by using nitrocefin disk.Results From 2015 to 2021,a total of 43 642 strains of Haemophilus species were isolated,accounting for 2.91％of the total clinical isolates and 4.07％of Gram-negative bacteria in CHINET program.Among the 40 437 strains of H.influenzae,66.89％were isolated from children and 33.11％were isolated from adults.More than 90％of the H.influenzae strains were isolated from respiratory tract specimens.The prevalence of β-lactamase was 53.79％in H.influenzae strains.The H.influenzae strains isolated from children showed higher resistance rate than the strains isolated from adults.Overall,779 strains of H.influenzae did not produce β-lactamase but were resistant to ampicillin(BLNAR).Beta-lactamase-producing strains showed significantly higher resistance rates to these antimicrobial agents than the β-lactamase-nonproducing strains.Of the 16 191 M.catarrhalis strains,80.06％were isolated from children and 19.94％isolated from adults.M.catarrhalis strains were mostly susceptible to both amoxicillin-clavulanic acid and cefuroxime,evidenced by resistance rate lower than 2.0％.Conclusions The emergence of antibiotic-resistant H.influenzae due to β-lactamase production poses a challenge for clinical anti-infective treatment.Therefore,it is very important to implement antibiotic resistance surveillance for H.influenzae and guide rational antibiotic use.All local clinical microbiology laboratories should actively improve antibiotic susceptibility testing and strengthen antibiotic resistance surveillance for H.influenzae.

Objective To investigate the distribution and antimicrobial resistance profiles of clinically isolated Haemophilus influenzae and Moraxella catarrhalis in hospitals across China from 2015 to 2021,and provide evidence for rational use of antimicrobial agents.Methods Data of H.influenzae and M.catarrhalis strains isolated from 2015 to 2021 in CHINET program were collected for analysis,and antimicrobial susceptibility testing was performed by disc diffusion method or automated systems according to the uniform protocol of CHINET.The results were interpreted according to the CLSI breakpoints in 2022.Beta-lactamases was detected by using nitrocefin disk.Results From 2015 to 2021,a total of 43 642 strains of Haemophilus species were isolated,accounting for 2.91％of the total clinical isolates and 4.07％of Gram-negative bacteria in CHINET program.Among the 40 437 strains of H.influenzae,66.89％were isolated from children and 33.11％were isolated from adults.More than 90％of the H.influenzae strains were isolated from respiratory tract specimens.The prevalence of β-lactamase was 53.79％in H.influenzae strains.The H.influenzae strains isolated from children showed higher resistance rate than the strains isolated from adults.Overall,779 strains of H.influenzae did not produce β-lactamase but were resistant to ampicillin(BLNAR).Beta-lactamase-producing strains showed significantly higher resistance rates to these antimicrobial agents than the β-lactamase-nonproducing strains.Of the 16 191 M.catarrhalis strains,80.06％were isolated from children and 19.94％isolated from adults.M.catarrhalis strains were mostly susceptible to both amoxicillin-clavulanic acid and cefuroxime,evidenced by resistance rate lower than 2.0％.Conclusions The emergence of antibiotic-resistant H.influenzae due to β-lactamase production poses a challenge for clinical anti-infective treatment.Therefore,it is very important to implement antibiotic resistance surveillance for H.influenzae and guide rational antibiotic use.All local clinical microbiology laboratories should actively improve antibiotic susceptibility testing and strengthen antibiotic resistance surveillance for H.influenzae.

ObjectiveTo investigate the influence of histone deacetylase 3 (HDAC3) on the occurrence, development of psoriasis-like inflammation in mice, and the relative immune mechanisms. MethodsHealthy C57BL/6 mice aged 6-8 weeks were selected and randomly divided into 3 groups: control group (Control), psoriasis model group (IMQ), and HDAC3 inhibitor RGFP966-treated psoriasis model group (IMQ+RGFP966). One day prior to the experiment, the back hair of the mice was shaved. After a one-day stabilization period, the mice in Control group was treated with an equal amount of vaseline, while the mice in IMQ group was treated with imiquimod (62.5 mg/d) applied topically on the back to establish a psoriasis-like inflammation model. The mice in IMQ+RGFP966 group received intervention with a high dose of the HDAC3-selective inhibitor RGFP966 (30 mg/kg) based on the psoriasis-like model. All groups were treated continuously for 5 d, during which psoriasis-like inflammation symptoms (scaling, erythema, skin thickness), body weight, and mental status were observed and recorded, with photographs taken for documentation. After euthanasia, hematoxylin-eosin (HE) staining was used to assess the effect of RGFP966 on the skin tissue structure of the mice, and skin thickness was measured. The mRNA and protein expression levels of HDAC3 in skin tissues were detected using reverse transcription real-time quantitative polymerase chain reaction (RT-qPCR) and Western blot (WB), respectively. Flow cytometry was employed to analyze neutrophils in peripheral blood and lymph nodes, CD4⁺ T lymphocytes, CD8⁺ T lymphocytes in peripheral blood, and IL-17A secretion by peripheral blood CD4⁺ T lymphocytes. Additionally, spleen CD4⁺ T lymphocyte expression of HDAC3, CCR6, CCR8, and IL-17A secretion levels were analyzed. Immunohistochemistry was used to detect the localization and expression levels of HDAC3, IL-17A, and IL-10 in skin tissues. ResultsCompared with the Control group, the IMQ group exhibited significant psoriasis-like inflammation, characterized by erythema, scaling, and skin wrinkling. Compared with the IMQ group, RGFP966 exacerbated psoriasis-like inflammatory symptoms, leading to increased hyperkeratosis. The psoriasis area and severity index (PASI) skin symptom scores were higher in the IMQ group than those in the Control group, and the scores were further elevated in the IMQ+RGFP966 group compared to the IMQ group. Skin thickness measurements showed a trend of IMQ+RGFP966>IMQ>Control. The numbers of neutrophils in the blood and lymph nodes increased sequentially in the Control, IMQ, and IMQ+RGFP966 groups, with a similar trend observed for CD4⁺ and CD8⁺ T lymphocytes in the blood. In skin tissues, compared with the Control group, the mRNA and protein levels of HDAC3 decreased in the IMQ group, but RGFP966 did not further reduce these expressions. HDAC3 was primarily located in the nucleus. Compared with the Control group, the nuclear HDAC3 content decreased in the skin tissues of the IMQ group, and RGFP966 further reduced nuclear HDAC3. Compared with the Control and IMQ groups, RGFP966 treatment decreased HDAC3 expression in splenic CD4⁺ and CD8⁺ T cells. RGFP966 treatment increased the expression of CCR6 and CCR8 in splenic CD4⁺ T cells and enhanced IL-17A secretion by peripheral blood and splenic CD4⁺ T lymphocytes. Additionally, compared with the IMQ group, RGFP966 reduced IL-10 protein levels and upregulated IL-17A expression in skin tissues. ConclusionRGFP966 exacerbates psoriatic-like inflammatory responses by inhibiting HDAC3, increasing the secretion of the cytokine IL-17A, and upregulating the expression of chemokines CCR8 and CCR6.

OBJECTIVE: To explore clinical effect of bone cement-strengthened pedicle screw technique in the correction of stage Ⅲ asymptomatic Kümmell disease with kyphosis. METHODS: A retrospective analysis was conducted on clinical data of 40 asymptomatic stage Ⅲ Kümmell disease patients admitted between March 2019 and December 2021, including 15 males and 25 females, aged from 61 to 81 years old with an average of (67.4±5.2) years old;according to different surgical methods, they were divided into percutaneous kyphoplasty group (PKP) and reinforced screw group. There were 18 patients in PKP group, including 7 males and 11 females, aged from 61 to 78 years old with an average of (66.2±5.5) years old;the courses of disease ranged from 5 to 12 months with an average of (7.33±1.78) months;bone mineral density(BMD) T values ranged from -2.45 to -4.00 with an average of (-3.08±0.46);2 patients with T₈-T₉, 10 patients with T₁₀-T₁₂, and 6 patients with L₁-L₂;treated with PKP. There were 22 patients in reinforced screw group, including 8 males and 14 females, aged from 65 to 81 years old with an average of (68.5±3.8) years old;the courses of disease ranged from 4 to 15 months with an average of (7.86±2.73)months;bone mineral density(BMD) T values ranged from -2.40 to -4.50 with an average of (-3.18±0.54);3 patients with T₈-T₉, 12 patients with T₁₀-T₁₂, and 7 patients with L₁-L₂;treated with bone cement reinforced pedicle screw internal fixation combined with kyphoplasty. Cobb angle and anterior margin height of the injured vertebra were compared before operation, 3 d and 12 months after operation. Visual analogue scale (VAS) and Oswestry disability index (ODI) were compared between two groups before operation and 12 months after operation. The incidence of postoperative complications was compared between two groups. RESULTS: All patients were followed up, PKP group followed up for 11 to 14 months with an average of (11.97±0.96) months and 10 to 14 months with an average of (12.05±1.09) months in reinforced screw group;there was no significant difference between two groups (P>0.05). Postoperative Cobb angle at 3 days and 12 months in reinforced screw group were (7.34±2.26) ° and (18.86±1.96) °, while in PKP group were (18.88±1.89) ° and (23.28±1.90) °;there were statistical difference between two groups (P<0.05). The anterior margin height of the injured vertebra in reinforced screw group were (25.28±1.33) mm and (19.62±2.22) mm at 3 days and 12 months after operation, while in PKP group were (18.61±2.16) mm and(15.93±1.34) mm;there were statistical difference between two groups (P<0.05). Cobb angle and the anterior margin height of the injured vertebra were significantly improved at 3 days and 12 months after operation between two groups (P<0.05). Postoperative VAS and ODI at 12 months in PKP group were (2.00±0.69) score and (13.44±4.02)%, while in reinforced screw group were(1.91±0.61) score and (10.18±4.26)%;which were significantly lower than (6.89±0.76) score and (36.33±3.40)% in PKP group, (7.23±0.75) score and (37.09±3.73) % in reinforced screw group before operation. There were no difference in postoperative VAS between two groups at 12 months (P>0.05);postoperative ODI in reinforced screw group at 12 months was lower than that in PKP group(P<0.05). There was no significant difference in complications between two groups (χ²=0.071, P>0.05). CONCLUSION PKP and bone cement reinforced nail combined with PKP could improve kyphotic deformity and postoperative function, and relieve pain. The application of bone cement-reinforced nail fixation technology could provide a more stable support, more obvious functional recovery, lower the risk of re-collapse of the injured vertebra, and maintain the long-term stability of spine.
Humans ; Male ; Female ; Aged, 80 and over ; Kyphosis/surgery* ; Aged ; Bone Cements ; Middle Aged ; Retrospective Studies ; Pedicle Screws ; Spinal Fractures/surgery* ; Fracture Fixation, Internal/methods* ; Bone Screws ; Kyphoplasty

Objective By observing and measuring the relevant data of the buccal branch of the facial nerve,the parotid duct and the facial artery,the positional relationship among the three was analyzed to avoid accidental injury to the buccal branch of the facial nerve and the parotid duct when ligaturing the facial artery during the operation.Methods Forty adult head and neck specimens were dissected to observe the relationship between the buccal branch of the facial nerve and the parotid duct,the course and positional relationship of the facial artery,and the relationship between the buccal branch of the facial nerve and the peripheral vascular network.The relevant diameters were measured with a vernier caliper.Results The buccal branch of the facial nerve was divided into the superior buccal branch and the inferior buccal branch,and there was no direct anastomosis or connecting fiber between the buccal branch of the facial nerve and the parotid duct.The superior buccal branch was relatively thick,and it has a relatively constant position,which was parallel to the parotid duct.The position of the inferior buccal branch was not constant and it ran on or slightly above the plane of angulus oris.The superior buccal branch was located(10.76±5.54)mm from the parotid duct,while the inferior buccal branch was positioned(6.84±4.06)mm away from the parotid duct.The course of the main trunk of the facial artery was relatively fixed.Moreover,if the branch of the facial artery was missing,other branches of the facial artery would extend to replace the missing branch artery.The main trunk of the facial artery had a diameter of(2.34±0.83)mm,and its branches formed anastomoses with the buccal branch of the maxillary artery,creating a vascular network in the parotid and buccal regions.There was a vascular network around the buccal branch of the facial nerve,which was mostly small branches of the facial artery and the superficial temporal artery.Conclusion The buccal branch of the facial nerve exhibits a consistent anatomic relationship with the parotid duct and the facial artery.During the ligation of the facial artery,the parotid duct can serve as a landmark to accurately locate the buccal branch of the facial nerve,thereby significantly reducing the risk of inadvertent injury to the buccal branch of the facial nerve and the parotid duct.