Objective:To introduce the concept and procedure of CTA guided precision flap surgery and report the preliminary clinical application.Methods:The theory of CTA guided precision flap surgery is: based on CTA high-throughput data, comprehensively evaluate the wound and potential donor sites, and select the best plan for wound repair. This article reviews 177 patients treated under the guidance of CTA guided precision flap surgery from August 2014 to December 2018. Among them, 131 were males and 46 were females; they were 7-72 years old, with an average age of 39.5 years. The tissue defects were: 74 cases of foot and ankle, 64 cases of wrist, 15 cases of calf, 11 cases of forearm and upper arm, 7 cases of thigh and perineum, 5 cases of face and neck, and 1 case of abdomen. The size of the defect was 2 cm×1 cm to 65 cm×50 cm. The recipient and donor sites were assessed based on CTA guided precision flap surgery, then choose the optimal flap to repair the defect. The flap types, outcomes and complications were recorded. The visual analogue scale (VAS), British Medical Research Council sensory rating scale, and revascularization assessments of digital replantation standard by Hand Surgery Branch of Chinese Medical Association was used to assess clinical results.Results:All flaps were uneventfully harvested as planned according to the CTA guided precision flap surgery concept.A total number of 181 flaps were harvested, including 125 free flaps and 56 pedicled flaps. The flap area rangedfrom 4 cm×3 cm to 40 cm×8 cm. After surgery, 165 cases were survival completely, 7 cases were total necrosis, 9 cases were partial necrosis. A total of 174 cases of flaps survived. The mean follow-up was 9.2 months (range, 6-60 months). After surgery 53 flaps were bulky, and 7 cases with other complications.At the last follow-up, only 6 patients had mild pain, the VAS score was 1-3. The sensation of the flaps recovered partially. According to the British Medical Research Council sensory rating scale: 68 cases were grade S2 and 106 cases were grade S3. According to the revascularization assessments of digital replantation standard by Hand Surgery Branch of Chinese Medical Association, 171 cases were excellent and 3 cases were good.Conclusion:The concept of precision flap surgery based on CTA can effectively guide flap surgery and achieve precise wound repair.

Objective:To introduce the concept and procedures of precise flap surgery in construction of knee defects and to report the preliminary clinical outcomes.Methods:The data of 16 patients with knee defects at 17 sides were retrospectively analyzed who had been treated under the guidance of the concept of precise flap surgery at Department of Orthopedic Surgery, The 920th Hospital of Joint Logistic Support Force of PLA from August 2014 to March 2022. There were 12 males and 4 females, aged 44(34, 54) years. The wounds were at the left side in 8 cases, at the right side in 7 ones and at bilateral sides in one, and their sizes ranged from 5 cm×3 cm to 15 cm×11 cm. The time from injury to surgery was 8.5(6.0, 13.0) days. Optimal repair protocols were chosen after the donor and recipient sites were evaluated according to the methods of precise flap surgery: a retrograde anterolateral thigh flap in 7 sides, a descending genicular artery perforator flap in 3 ones, a saphenous artery flap in 2 ones, and a superior genicular lateral artery perforator flap, a popliteal artery perforator flap, a medial sural perforator propeller flap, a peroneal artery perforator propeller flap, and a randomized flap in one, respectively. The flap sizes ranged from 10 cm×6 cm to 15 cm×15 cm. The outcomes and complications of skin flap repair, and functional recovery of the affected limb were recorded.Results:All the flaps at 17 sides survived after surgery; 3 cases developed distal edge necrosis which responded to dressing change. The follow-ups for the 16 patients were 14.5(10.0, 28.0) months. All the flaps presented with good color, texture and contour. Flap bulking, local osteomyelitis, and scar ulcer was found in one case respectively. According to the revascularization assessments in the digital replantation criteria by Hand Surgery Society, Chinese Medical Association, all the flaps at 17 sides were excellent. Accoding to the knee functional evaluation of Hospital for Special Surgery (HSS) at the last follow-up, the 17 affected limbs scored 86(80,91) points, yielding 9 excellent, 7 good and 1 fair sides.Conclusion:Although the defects and donor sites around the knee vary greatly, precise flap surgery may lead to effective control of the variations, choice of an optimal reconstruction protocol, and precise wound repair.

Objective:To investigate the efficacy of digital reconstruction technology in assisted design of lobulated deep inferior epigastric perforator flap (DIEPF) for surgical reconstruction of large defect in lower extremity.Methods:From January 2017 to January 2022, a study was carried out to retrospectively analyse 8 patients who had massive soft tissue defects in lower extremities were admitted in the Department of Orthopaedic Surgery of the 920 Hospital of Joint Logistic Support Force of Chinese PLA. The size of defects varied from 16.0 cm×12.0 cm-28.0 cm×22.0 cm. CTA scans were performed over abdominal aorta and the arteries of lower extremities. Three-dimensional model of DIEPF and vascular pedicles were reconstructed by Mimics software. According to the shape and size of the wound, targeted perforators were determined on the 3D images, and precisely mapped in a digitised rectangular coordinate system. The lobulated flap was then digitally designed in the 3D coordinate system. Flaps were harvested according to preoperative digital designs for the reconstruction of large defects in the lower extremities. The donor site was sutured directly. The flaps and recovery of lower extremities were observed though postoperative follow-ups and were conducted through visits of outpatient clinics and distance interviews via telephone and WeChat. Recoveries of lower extremities were evaluated using Maryland ankle-foot function scoring system.Results:The 3D reconstructed models of the vessels in donor sites were successfully completed for all patients. The harvests of lobulated DIEPF were successfully guided by the digital designs. Fifteen lobes of lobulated DIEPF survived successfully in all 8 patients. All donor sites were closed in the stage-I. Necrosis occurred at the distal tip of a lobulated flap due to a local venous occlusion, and healed after debridement and re-suture. Four patients received further flap debulking surgery. Time of postoperative follow-ups had ranged 15-27 months, with an average of 20 months. At the last follow-up, all the flaps had satisfactory appearance with linear scars at the donor sites. All fractures were healed. Five patients achieved Maryland's ankle-foot function score in excellent, 2 in good, and 1 was acceptable.Conclusion:Digital reconstruction technology can accurately map the perforators and reasonably assist the design of lobulated flaps. A lobulated DIEPF offers a wider area for flap excision and allows a primary closure of the donor sites. Combination of the 2 advantages of a lobulated DIEPF can be effectively applied in reconstruction of a large-sized defect in lower extremity.

Objective:To introduce the methods of retrograde anterolateral thigh flaps in repairing anterior knee joint wounds under the concept of precise flap surgery and to explore the clinical effects.Methods:A retrospective observational study was conducted. From August 2014 to March 2022, 7 patients with anterior knee joint wounds were treated with retrograde anterolateral thigh flap under the guidance of the concept of precise flap surgery in the 920 th Hospital of Joint Logistic Support Force of PLA. Among them, 6 were males and 1 was female, aged 36 to 66 years. The sizes of wounds were 7 cm×5 cm to 15 cm×11 cm after debridement. All the patients were performed with computed tomography angiography (CTA), the donor and recipient sites were evaluated according to the precise flap surgery method, and the optimal pedicle, perforator, and pivot of flaps were chosen. The flap sizes were 10 cm×6 cm to 20 cm×9 cm, and all the donor sites of flaps were sutured directly. The consistency of the intraoperative exploration with preoperative CTA was observed. The flap survival and occurrence of complications were observed after surgery. The color, appearance, texture, and occurrence of complications were followed up. At the last follow-up, the blood supply of flaps was evaluated using the blood circulation evaluation indicators of Chinese Medical Association Hand Surgery Branch's trial criteria for digital replantation function evaluation, and the function of knee joint was evaluated using knee joint scoring system of hospital for special surgery. Results:The flap condition of the intraoperative exploration was completely consistent with that of preoperative CTA. The flaps survived completely after surgery in 6 patients, while necrosis at the edge of the flap occurred in 1 patient, which healed after dressing change. All the flaps were hyperperfused after surgery, and the color of the flaps gradually became normal after 1 week. Follow-up of 7 to 44 months showed that the color, appearance, and texture were well in all the patients, while local osteomyelitis at the proximal tibia occurred in 1 patient. At the last follow-up, all the 7 patients had excellent blood circulation; the function score of knee joint was 69 to 91, which was evaluated as excellent in 3 cases, good in 3 cases, and fair in 1 case.Conclusions:The retrograde anterolateral thigh flap has large variations, and the application of precise flap surgery method can accurately understand the variations before surgery, guide the design and cutting of the flaps, thus achieving precise repair of anterior knee joint wounds, with good repair outcome.

Objective:To develop a grading system for necrosis of pedicled flaps in reconstruction of foot and ankle, and to verify its effectiveness and repeatability.Methods:A retrospective observational study was conducted. A total of 40 necroses of foot and ankle pedicled flaps were selected by 2 senior surgeons based on the flap surgery performed by the same surgical group in Department of Orthopaedic Surgery, the 920 Hospital of Joint Logistic Support Force of PLA from January 2010 to January 2022. A grading system for pedicled flap necrosis was proposed by a working group and the 40 necrotic flaps were graded. The coincidence rate was calculated to evaluate the effectiveness of the grading system through correlation studies between grading and clinical treatment. One photo of a typical postoperative necrotic flap was collected from each of the 40 flaps. Then 5 extramural surgeons were asked to grade the necroses shown on the photos according to the proposed grading system. Moreover, weighted Kappa analysis was performed on the results of proposed grading system and also on the standard grading currently in use, to evaluate the repeatability of the proposed grading system. Evaluated data were expressed by Mean±SD, and the coincidence rate was expressed by percentage. The reproducibility was studied by weighted Kappa analysis.Results:Of the 40 necrotic flaps, 7 flaps were classified in Grade I, 16 in Grade Ⅱ, 12 in Grade Ⅲ and 5 in Grade IV. In comparison with the actual treatment methods, the overall coincidence rate of the grading system was 92.5%. It indicated that the proposed grading system could effectively guide the selection of a treatment procedure. The average weighted Kappa coefficient of surgeons was at 0.628 with a 95% confidence interval (95%CI) between 0.460-0.796, which was strongly consistent with the standard of the grading system currently in use.Conclusion:The grading system for necrosis of pedicled flap in reconstruction of foot and ankle proposed in this study is simple and clear. It is able to effectively guide the treatment of flap necrosis. The preliminary validation shows that the classification system has good repeatability.

Objective:To investigate personal exposures to nitrogen oxides(NOX)and nitrogen di-oxide(NO2)and the influence of baseline personal characteristics,living environment and daily activity patterns of the participants on the exposures among adults over 35 in Tianjin and Shanghai.Methods:In this panel study,91 healthy nonsmoking adults aged over 35 from Tianjin and Shanghai participated in our study.The study was conducted in summer and winter.The participants were followed for three times with an interval of at least two weeks.Only participants in Shanghai were followed once in winter because of the COVID-19 pandemic.Twenty-seven participants completed follow-up visits in both seasons.We measured their 24 h personal exposures to NOX and NO2and collected their baseline and time-activity in-formation through questionnaire/diary.The linear mixed model was used to analyze the associations be-tween potential influencing factors and personal NOX and NO2 exposure levels.Results:There were 349 follow-up visits with valid 24 h personal NO2 and NOX exposure measurements in the two cities.The ave-rage 24 h personal exposures to NO2 and NOX(volume fraction)in Tianjin participants were 18.0 x 10-9 and 26.2 × 10-9 in summer,and 31.0 x 10-9 and 54.9 x 10-9in winter,respectively;and the average 24 h personal exposures to NO2 and NOX in Shanghai participants were 38.7 x 10-9and 100.0x10-9in summer,and 45.5 x10-9 and 139.2 x 10-9 in winter,respectively.The results of univariate regression analysis showed that their personal NOX exposure levels were significantly associated with city,season,gender,average daily cooking times,and ambient NO2 concentrations measured at fixed-site monitoring stations.In addition to the above factors,the personal NOX exposure levels were also significantly associ-ated with educational level and the personal NO2 exposure levels were also significantly associated with passive smoking,average daily home time,cooking energy type,residential distance from main traffic road,and use of kitchen ventilators.Multivariate regression analysis showed that the personal exposure levels of NO2 and NOX were significantly lower in Tianjin than that in Shanghai,were significantly lower in summer than that in winter,and were significantly and positively associated with ambient NO2 concen-trations measured at fixed-site monitoring stations.In addition,personal NOX exposure levels were signifi-cantly lower in females than in males,and personal NO2 exposure levels were significantly positively asso-ciated with average daily cooking times and significantly inversely associated with average daily home time.For every interquartile range(IQR)increase(12.7 × 10-9)in ambient NO2,the personal NO2 exposure levels increased by 27.5％(95％CI:17.0％-38.9％),and personal NOX exposure levels in-creased by 16.1％(95％CI:7.1％-25.8％).Conclusion:Season,city and ambient NO2 concentra-tions are significant influencing factors of personal exposure levels of NO2and NOX At the same time,the personal exposures levels of NO2 are also affected by lifestyle factors.Our study provides scientific evi-dence for making precise air pollution control decisions and reducing the exposure levels of NOX in the population.