Objective:To investigate the risk factors of muscle necrosis in patients with acute compartment syndrome（ACS）.Methods:A retrospective case-control study was conducted for clinical data of 111 ACS patients admitted to West China Hospital, Sichuan University from January 2010 to December 2020, including 84 males and 27 females; age 18-76 years [45（36, 55）years]. Muscle necrosis was presented in 35 patients（necrotic muscle group）, but was not seen in 76 patients（non-necrotic muscle group）. The univariate analysis was performed for the two groups in the demographic data（sex, age, ethnicity, body mass index, smoking history, chronic comorbidities）, injury patterns [ mechianism of injury（low energy injury, high energy injury, crush injury, other injury）, time from injury to treatment, first visit or not, combination with bone fracture or not, open injury or not, presence of tension blisters or not], medical treatment（number of debridements, fasciotomy or not）and laboratory indicators [hemoglobin（Hb）, platelet count（PLT）, white blood cell count（WBC）, prothrombin time（PT）, international normalized ratio（INR）, partially activated prothrombin time（APTT）, fibrinogen（FIB）, D-Dimer（D-D）, alanine aminotransferase（ALT）, aspartate aminotransferase（AST）, albumin（ALB）, intravenous blood glucose（GLU）, creatine kinase（CK）, peak value of CK during hospitalization（natural logarithmic conversion, lnCK）, serum sodium（NA）, serum potassium（K）, serum calcium（CA）]. Further multivariate logistic regression was performed to analyze the independent risk factors of muscle necrosis in ACS patients.Results:The univariate analysis showed that there were statistically significant differences between the two groups in the mechanism of injury, first visit or not, combination with bone fracture or not, number of debridements, Hb, PT, INR, D-D, AST, ALB, GLU, CK and lnCK（ P<0.05）, while not in the basic data, time from injury to treatment, open injury or not, presence of tension blisters or not, fasciotomy or not, PLT, WBC, APTT, FIB, ALT, NA, K and CA（ P>0.05）. The multivariate logistic regression analysis showed that high energy injury（ OR=5.143, 95% CI 1.216-21.758, P<0.05）, crush injury（ OR=22.313, 95% CI 2.625-189.635, P<0.05）, other mechanism of injury（ OR=9.019, 95% CI 1.036-78.554, P<0.05）, first visit or not（ OR=0.071, 95% CI 0.006-0.819, P<0.05）, Hb（ OR=0.979, 95% CI 0.961-0.998, P<0.05）, GLU（ OR=1.218, 95% CI 1.020-1.455, P<0.05）and lnCK（ OR=1.805, 95% CI 1.235-2.639, P<0.05）were significantly related with muscle necrosis. Conclusion:The mechanism of injury, first visit or not, Hb, GLU and lnCK are the independent risk factors of muscle necrosis in patients with ACS.

Objective: To observe the position of the electrode in the cochlea following cochlear implantation by cone beam computed tomography (CBCT). Methods: Twenty-five children who received cochlear implantation and CBCT examinations in the Department of Otorhinolaryngology Head and Neck Surgery from the Second Hospital of Shandong University between January 2016 and December 2017 were selected. There were 15 males (17 ears) and 10 females (10 ears). The age ranged from 0.5 to 7.0 years old, with a median age of 1.6 years. 23 patients with unilateral implantation and two patients with bilateral implantation. The implants were all Med-El standard 12-electrode contact arrays. The CBCT was used to determine the position of the electrode in the cochlea, the distance between the electrode contacts and modiolus, and intracochlear insertion length of the electrode arrays. SPSS Statistics, version 22.0 was used for data processing and statistical analysis. Results: CBCT images could clearly demonstrate the structure of round window, oval window, modiolus, osseous cochlear duct, osseous spiral lamina, and electrodes. The electrode arrays of all the children were fully implanted into the cochlea. 26 of the electrode arrays were located in the scala tympani and one of them was inserted into the scala vestibular. The mean intracochlear insertion length of the electrode arrays was 30.23 (95%CI, 30.04-30.71) mm. The distance between the electrode contacts and modiolus gradually increased at the 1-4th electrode contacts and reached the maximum at the 4th electrode contacts with an average of 1.10 mm (95%CI, 1.02 to 1.18 mm), and then gradually decreased from the 5th electrode contacts. Conclusions CBCT can clearly show cochlear fine structures and therefore accurately assess the electrode position following cochlear implantation.