Objective:To analyze the setup and residual errors of spinal cord during online CT-guided radiotherapy for patients with esophageal cancer, and to discuss the necessity of segmental extension of spinal cord.Methods:According to the radiotherapy site, 60 cases of esophageal cancer were divided into the neck, chest and abdomen groups, 20 cases in each group. Cervical pleura or vacuum bag was fixed, IMRT technology was adopted, and pre-treatment CT images were obtained by CT Vision, and 20 consecutive CT scans were collected for each case. CT images were imported into MIM software. The parameters of the setup errors were processed and extracted. The CT spinal cord was delineated for verification and planning, and the Dice coefficient, Hausdorff maximum distance and centroid coordinate of the delineated spinal cord were processed and extracted. Compatibility anova data were adopted. The calculation formula of the extension margin is M PRV= 1.3 ∑ total+ 0.5 σ total. Results:Residual centroid method was employed. Non-on-line and on-line CT-guided radiotherapy, the extension margins of neck, chest, abdominal spinal cord in the x-, y-and z-axis were 3.86, 5.37, 6.36 mm; 3.45, 3.83, 4.51 mm; 4.05, 4.83, 7.06 mm, vs, 2.85, 2.19, 2.83 mm; 2.32, 2.20, 2.16 mm; 2.86, 2.21, 2.83 mm, respectively. During residual Hausdorff distance method, non-on-line and on-line CT guided radiotherapy, the extension margins of neck, chest, abdominal spinal cord in the x-, y-and z-axis were 3.10, 5.33, 6.15 mm; 3.30, 3.77, 4.61 mm; 3.35, 4.76, 6.87 mm, vs, 2.12, 2.06, 2.32 mm; 2.12, 2.06, 2.32 mm; 2.12, 2.06, 2.32 mm, respectively.Conclusion:The setup errors and residual errors are different in each segment of spinal cord. Henc, different extension margins should be given.

Objective:To investigate the clinical application effect of latissimus dorsi muscle flap in reconstruction of muscle strength around shoulder after electric burns.Methods:From March 2014 to September 2020, 13 patients with electric burns and severe injury around shoulder were admitted to the First Affiliated Hospital of Air Force Medical University, including 11 males and 2 females, aged 19-55 years. A retrospective observational study was conducted. The left upper limbs were injured in 8 cases, and the right upper limbs were injured in 5 cases, all with eschar wounds of Ⅲ-Ⅳ degree. Among which, there were biceps defects in 6 cases, deltoid defects in 3 cases, triceps defects in 2 cases, and composite defects of multiple muscles around shoulder in 2 cases. The surgery was carried out in two stages. In stage Ⅰ, debridement and exploration of electric burn wounds around shoulders were conducted to preserve local tissue and save the limb as much as possible on the premise of guaranteeing the stability of the body condition. After the last debridement, the wound area was from 10 cm×6 cm to 40 cm×15 cm, the muscle defect area was from 8 cm×4 cm to 19 cm×12 cm, and the humerus was exposed in 7 patients. In stage Ⅱ, according to the residual limb defect degree, muscle reconstruction around shoulder was conducted with the latissimus dorsi muscle flap, and area of the latissimus dorsi muscle flap was 15 cm×6 cm to 20 cm×18 cm. The residual wounds were repaired with autologous split-thickness skin grafts of head, and the donor sites of muscle flaps were sutured directly. The survivals of the muscle flaps and wounds closure post operation, and the appearances of the donor sites and recipient sites during follow-up were observed. At the last follow-up, the shoulder joint function was evaluated using the trial standard for the evaluation of the functions of the upper limbs of the Hand Surgery Society of the Chinese Medical Association, and the satisfaction degrees of patients for appearance and function recoveries of shoulder were investigated by self-made questionnaire with reference to the concise test scoring system of shoulder joint.Results:All of the 13 muscle flaps around shoulder survived after surgery. Two patients had residual wounds in the skin grafting area, the wound in one of the patients was healed after dressing change, and the wound in the other 1 patient was healed with the second autologous split-thickness skin grafting on head after dressing change. During follow-up of 6 to 18 months for all the patients, the muscle flaps of patients were full in appearance and not bloated, and atrophic scar in the repaired area was soft in texture and closed with normal skin around. Linear suture scars were left in the donor sites of muscle flaps, which did not affect the overall appearance. At the last follow-up, the active abduction range of the shoulder joint was 60-90°, upward lift on 120-180°, muscle strength recovered to level Ⅳ and above in 8 cases and to level Ⅲ in 5 cases, and the shoulder joint function was evaluated as excellent in 8 cases and good in 5 cases; 10 patients were very satisfied and 3 patients were satisfied with the appearance and function recovery of the shoulders.Conclusions:The application of latissimus dorsi muscle flap provides a better choice for the muscle strength reconstruction around shoulder after electric burns, with good appearance of the operative areas and ideal prognosis of upper limb function.