Objective To explore the clinical efficacy of 3D printing technique in assisting sacroiliac screwing in combination with front ring nail-rod system for treatment of unstable pelvic fractures.Methods From July 2015 to June 2017,3D printing technique was used to assist the sacroiliac screwing in combination with front ring nail-rod system for 16 patients with unstable pelvic fracture at Orthopaedic Center,The Fourth People's Hospital of Zigong.They were 9 males and 7 females,aged from 19 to 60 years (average,39.8 years).By the Tile classification,5 cases were type B1,6 type B2,3 type B3 and 2 type C.Their operation duration,bleeding,fluoroscopy frequency,incision length,postoperative fracture reduction,success rate of sacroiliac screwing,accuracy of sacroiliac screwing,perioperative complications,weight-bearing exercise time,fracture healing time and the Majeed scores at the last follow-up were documented.Results All the 3D models and navigation templates were successfully designed and printed.Surgery succeeded in all the patients.Follow-ups ranged from 6 to 18 months,averaging 13.3 months.The bleeding ranged from 100 to 250 mL,averaging 162.4 mL;the operation duration ranged from 60 to 120 min,averaging 73.2 min;the intra-operative fluoroscopy frequency ranged from 13 to 31 times,averaging 17.4 times;the incision length ranged from 16 to 32 cm,averaging 21.1 cm.All the incisions healed by the first intention and all the fractures obtained osseous union after 90 to 120 d (average,102.3 d).No significant complications like neurovascular injury or pulmonary embolism happened.The weight-bearing exercise time ranged from 25 to 40 d,averaging 31.5 d.According to the Matta imaging scores,the reduction was rated as excellent in 12 cases and good in 4.Altogether 28 screws were inserted with a success rate of 100％.Compared with the preoperative simulated screwing,the actual screwing angle deviated postoperatively by 0.12° ± 0.32°,the X axis by 0.36 ± 1.24 mm,the Y axis by 0.36 ± 1.24 mm and the Z axis by 0.22 ± 1.26 mm,showing no statistically significant difference between the actual 3D deviations and the test value of 0 (P ＞ 0.05).Conclusion In the treatment of unstable pelvic fractures,3D printing technique can be used in preoperative preparation of the connecting rod in the front ring nail-rod system to assist the sacroiliac screwing,significantly shortening the operation duration,reducing bleeding,ensuring safe and accurate screwing,and facilitating functional recovery.

Objectives To evaluate the 3D printed navigation template used to assist axis pedicle lag-screw placement in the treatment of atypical Hangman's fracture(AHF).Methods From May 2015 to January 2017,12 patients with AHF were treated at Department of Orthopedics,The Fourth Peopled Hospital of Zigong.In their operation,the axis pedicle lag-screw placement was assisted by a 3D printed navigation template.They were 8 men and 4 women,aged from 27 to 53 years(average,45.6 years).There were 7 cases of type Ⅰ,4 cases type Ⅱ and one case of type HA according to the Levine-Edwards classification.There were 2 cases of grade D and 12 cases of grade E according to the assessment of America Spinal Injury Association(ASIA).Their preoperative and postoperative neck pain was evaluated by visual analogue scale(VAS);their preoperative and postoperative ranges of cervical motion were recorded and compared.To evaluate the postoperative safety of screws,the insertion point,position within the pedicle,axial angle and sagittal angle of the screws and maximum fracture displacement were compared between actual operation and simulative operation.Results A total of 12 guide plates were designed and printed;a total of 24 lag-screws were placed.All patients underwent surgery uneventfully.They were followed up for 12 to 20 months,with an average of 14.7 months.Two patients with ASIA grade D recovered to ASIA grade E at the last follow-up.All patients showed a significant improvement in neck pain.Their VAS score at 5 days after surgery(5.86±2.02) was significantly lower than their preoperative score(8.29±1.88)(P<0.05) and their VAS score at the last follow-up(1.73±0.87) was also significantly lower than that at 5 days after surgery(P<0.05).Their range of cervical motion at 6 months after surgery was significantly larger than that at 3 months after surgery(P<0.05);their range of cervical motion returned to normal roughly at the last follow-up,showing no significant difference from that at 6 months(P>0.05).Their postoperative X-ray and CT images showed that the dislocation was all corrected.The last follow-up showed no obvious vertebral instability,screw breakage or loosening.Postoperative CT showed that the 24 screws had been located completely in the pedicle(grade 0),indicating that the screw placement was 100% accurate.The postoperative deviation at insertion point(0.70±0.78 mm),deviation within the pedicle(1.3±0.82 mm),axial angle(8.26°±0.88°) and sagittal angle(22.62°±0.86°) of the screws showed no significant differences from the preoperative simulative data(P>0.05).There was a significant difference in the maximum fracture displacement between the preoperative data(3.94±0.38 mm) and the postoperative data(2.21±0.39 mm)(P<0.05).Conclusion The 3D printed navigation template can be used to better assist axis pedicle lag-screw placement in the treatment of AHF,because it ensures safe screw placement,leading to good reduction and fixation and precise match with the preoperative plan.

Objective: To investigate the epidemiological characteristics and its associated risk factors of lower urinary tract symptoms in young Chinese obese males. Methods: A total of 126 young males aged 20-40 years admitted to Beijing Friendship Hospital, Capital Medical University were enrolled into two different groups in this study, including 74 obese patients visited metabolic weight loss clinic were included in the experimental group, and 52 conditionally healthy persons were included in the control group. Blood pressure (systolic blood pressure, diastolic blood pressure), insulin resistance (fasting blood glucose, insulin, C-peptide), blood lipid metabolism (triglycerides, high-density lipoprotein cholesterol), and sex hormones (estrogen) of the two groups of subjects. Hormones, serum testosterone), C-reactive protein (CRP), International prostate symptom score (IPSS) and quality of life score (QOL). were compared between the two groups of subjects. Comparisons of measurement data between groups were statistically analyze by t test, expressed by mean ± standard deviation (Mean±SD); the correlation between body mass index and LUTS was analyzed by Spearman rank correlation, and the risk factors of LUTS and clinical variables were analyzed by univariate logistic regression. The significant variables were analyzed by multivariate logistic regression. Results: There were significant statistical differences between experimental group and control group in terms of systolic blood pressure [(144.30±15.78) mmHg vs (125.9±66.11) mmHg, P<0.001], diastolic blood pressure [(89.46±12.76) mmHg vs (81.35±4.58) mmHg, P=0.001], and fasting blood glucose [(6.73±3.15) mmol/L vs (5.26±1.47) mmol/L, P=0.016], insulin [(26.60±19.09) mg/dL vs (13.43±7.68) mg/dL, P<0.001], C-peptide [(4.20±1.73) ng/mL vs (1.59±0.52) ng/mL, P=0.001], triglycerides [(2.42±1.88) mg/dL vs (1.45±0.79) mg/dL, P=0.007), estrogen [(52.32±21.77) ng/L vs (42.11±12.19) ng/L, P=0.023] and CRP [(6.49±4.96) mg/L vs (1.62±1.53) mg/L, P=0.037], but no statistical difference regarding high-density lipoprotein [(1.10±0.55) mg/dL vs (1.06±0.26) mg/dL, P=0.669] and serum testosterone [(275.00±100.68) ng/dL vs (280.28±85.52) ng/dL, P=0.823]. In addition, the experimental group had higher IPSS[(3.81±1.88) scores vs (0.69±0.30) scores, P<0.001] and QOL scores [(2.76±0.68) scores vs (0.12±0.08) scores, P<0.001] than the control group, and higher risk of LUTS [86.49% vs 42.31%, P<0.001], especially moderate LUTS ( 21.62% vs 0, P=0.011). Spearman rank correlation analysis showed that obesity (body mass index≥30 kg/m²) was significantly associated with moderate LUTS risk (r=0.407, P<0.001); Univariate logistic regression analysis showed that systolic blood pressure, insulin, and C-peptide were important risk factors of moderate LUTS in young obese patients (P=0.009, 0.029, 0.002). Systolic blood pressure and fasting C-peptide were independent risk factors by multivariate logistic regression analysis (P=0.011, 0.003). Conclusions The middle severity of LUTS was prevalent in young obese males, and systolic blood pressure and C-peptide were its significant independent risk factors.