A Two-Dimensional Mathematical Model to Analyze Thermal Variations in Skin and Subcutaneous Tissue Region of Human Limb during Surgical Wound Healing

During wound healing, the metabolic activity associated with each phase must occur in the proper sequence, at a specific time, and continue for a specific duration at an optimal intensity. Any disturbance in appropriate thermal environment may complicate the wound healing process and may give rise to wound infection. In the presented paper a transient state two-dimensional mathematical model has been developed to analyse thermal variations in skin and subcutaneous tissue (SST) region of human limb. Due to circular shape of human limb, model has been developed in polar coordinates. The domain of the study consists of two types of tissues: abnormal tissues and normal tissues. The post surgery peripheral tissue of human limb during healing time is considered as abnormal tissues. The effect of variable density of blood vessels in dermal layer of both tissues on the physical and physiological parameters is incorporated in the model. The effect of healing on physiological parameters of abnormal tissue is incorporated by considering the physiological parameters to be function of time “t”. The effect of different climatic conditions is considered in the model. Taking into account the variable core temperature due to anatomy of arteries and variable physiological parameters in dermal layer of peripheral region, the well known Pennes’ bio heat equation is used to analyse the time-dependent temperature distribution of both normal and abnormal tissues. Comparison between temperature profiles of both normal and abnormal tissue has been done using finite element approach with bilinear shape functions in polar coordinates. A computer program in MATLAB has been developed to simulate the results.

Reconstruction of the lower back wound with delayed infection after spinal surgery:A case report

BACKGROUND Orthopedic surgeries after device implantation are susceptible to infections and may require device removal in the worst cases.For this reason,many efforts are being made to control infections after spinal surgery;however,the number of infec-tion cases is increasing owing to the increasing number of elderly citizens.CASE SUMMARY A 75-year-old male with a chronic spinal defect due to previous spine surgery underwent reconstruction using a perforator-based island flap.After bursectomy and confirmation that there was no connection with the deep tissue,reconstruction was performed.However,wound disruption occurred with abscess formation on postoperative day 29,which led to an imaging workup revealing delayed deep tissue infection.CONCLUSION Infection is one of the most common causes of surgical wound dehiscence and is associated with devastating results if not controlled promptly and definitively.Surgeons should always suspect delayed infections when reconstructing chronic soft tissue defects.

Wound Inflammatory Cells after Cardiac Surgery and the Patients’ Survival

Objective: To find out possible associations between wound inflammatory cell response and the patients’ survival. Background: Several articles have written about the effects of single inflammatory cell types on wound healing but little is known about the interaction of these cells on survival. The methods used in this study have made possible this kind of exploration. Methods: One hundred patients, aged from 41 to 78 years, underwent open heart surgery in the years 1998-1999 and were studied by using the Cellstick device for harvesting wound inflammatory cells during the first 24 hours after surgery. The results of the differential count were computerized by using artificial neural network for obtaining wound inflammatory cell node (WICN). The patients were followed up for sixteen years or to the death. WICN values were compared with the patients’ survival. Results: WICN reflects survival better than any single type of wound inflammatory cells alone (HR = 3.1;p = 0.081 for low/high WICN at 10 year survival). From several clinical characteristics diabetes only predicted shorter survival time (HR = 5.5;p = 0.014 for 10 year survival) better than WICN. Conclusion: These results support the view that regularly timed cell-to-cell ratios in wound inflammation, most often seen as high WICN, reflect beneficial survival. Instead, aberrant counts of inflammatory cells in the wounds lead to low WICN and often to the patients’ shorter survival.

Comparison of modified gunsight suture technique and traditional interrupted suture in enterostomy closure

BACKGROUND Prophylactic enterostomy surgery is a common surgical approach used to reduce the risk of anastomotic leakage in patients who have undergone partial intestinal resection due to trauma or tumors.However,the traditional interrupted suturing technique used in enterostomy closure surgery has several issues,including longer surgical incisions and higher incision tension,which can increase the risk of postoperative complications.To address these issues,scholars have proposed the use of a“gunsight suture”technique.This technique involves using a gunsight incision instead of a traditional linear incision,leaving a gap in the center for the drainage of blood and fluid to reduce the risk of infection.Building on this technique,we propose an improved gunsight suture technique.A drainage tube is placed at the lowest point of the incision and close the gap in the center of the gunsight suture,which theoretically facilitates early postoperative mobility and reduces the burden of dressing changes,thereby reducing the risk of postoperative complications.AIM To compare the effectiveness of improved gunsight suture technique with traditional interrupted suture in closing intestinal stomas.METHODS In this study,a retrospective,single-center case analysis was conducted on 270 patients who underwent prophylactic ileostomy closure surgery at the Department of Colorectal Surgery of Qilu Hospital from April 2017 to December 2021.The patients were divided into two groups:135 patients received sutures using the improved gunsight method,while the remaining 135 patients were sutured with the traditional interrupted suture method.We collected data on a variety of parameters,such as operation time,postoperative pain score,body temperature,length of hospital stays,laboratory indicators,incidence of incisional complications,number of wound dressing changes,and hospitalization costs.Non-parametric tests and chi-square tests were utilized for data analysis.RESULTS There were no statistically significant differences in general patient information between the two groups,including the interval between the first surgery and the stoma closure[132(105,184)d vs 134(109,181)d,P=0.63],gender ratio(0.64 vs 0.69,P=0.44),age[62(52,68)years vs 60(52,68)years,P=0.33],preoperative body mass index(BMI)[23.83(21.60,25.95)kg/m²vs 23.12(20.94,25.06)kg/m²,P=0.17].The incidence of incision infection in the improved gunsight suture group tended to be lower than that in the traditional interrupted suture group[(n=2/135,1.4%)vs(n=10/135,7.4%),P<0.05],and the postoperative hospital stay in the improved gunsight suture group was significantly shorter than that in the traditional interrupted suture group[5(4,7)d vs 7(6,8)d,P<0.05].Additionally,the surgical cost in the modified gunsight suture group was slightly lower than that in the traditional suture group[4840(4330,5138)yuan vs 4980(4726,5221)yuan,P>0.05],but there was no significant difference in the total hospitalization cost between the two groups.CONCLUSION In stoma closure surgery,the improved gunsight technique can reduce the incision infection rate,shorten the postoperative hospital stay,reduce wound tension,and provide better wound cosmetic effects compared to traditional interrupted suture.

Laparoscopic vs mini-incision open appendectomy

AIM: To compare laparoscopic vs mini-incision open appendectomy in light of recent data at our centre.METHODS: The data of patients who underwen appendectomy between January 2011 and June 2013 were collected. The data included patients' demographic data, procedure time, length of hospital stay, the need for pain medicine, postoperative visual analog scale o pain, and morbidities. Pregnant women and patients with previous lower abdominal surgery were excluded Patients with surgery converted from laparoscopic appendectomy(LA) to mini-incision open appendectomy(MOA) were excluded. Patients were divided into two groups: LA and MOA done by the same surgeon. The patients were randomized into MOA and LA groups a computer-generated number. The diagnosis of acute appendicitis was made by the surgeon with physica examination, laboratory values, and radiological tests(abdominal ultrasound or computed tomography). Al operations were performed with general anaesthesia The postoperative vision analog scale score was recorded at postoperative hours 1, 6, 12, and 24. Patients were discharged when they tolerated normal food and passed gas and were followed up every week for three weeks as outpatients.RESULTS: Of the 243 patients, 121(49.9%) underwen MOA, while 122(50.1%) had laparoscopic appendectomy There were no significant differences in operation time between the two groups(P = 0.844), whereas the visua analog scale of pain was significantly higher in the open appendectomy group at the 1st hour(P = 0.001), 6th hour(P = 0.001), and 12 th hour(P = 0.027). The need for analgesic medication was significantly higher in the MOA group(P = 0.001). There were no differences between the two groups in terms of morbidity rate(P = 0.599)The rate of total complications was similar between the two groups(6.5% in LA vs 7.4% in OA, P = 0.599). Al wound infections were treated non-surgically. Six ou of seven patients with pelvic abscess were successfully treated with percutaneous drainage; one patient requiredsurgical drainage after a failed percutaneous drainage. There were no differences in the period of hospital stay, operation time, and postoperative complication rate between the two groups. Laparoscopic appendectomy decreases the need for analgesic medications and the visual analog scale of pain.CONCLUSION: The laparoscopic appendectomy should be considered as a standard treatment for acute appendicitis. Mini-incision appendectomy is an alternative for a select group of patients.

Low dose of lipopolysaccharide pretreatment can alleviate the inflammatory response in wound infection mouse model

Purpose： To assess the effects of lipopolysaccharide （LPS） pretreatment on wound infection mouse model and evaluate the biological safety of the optimal pretreatment dose in vivo. Methods： Mice were pretreated with LPS of different doses at 48 and 24 h before femoral medial lon- gitudinal incision was made and infected with different bacteria. Results： It is showed that 0.5 mg/kg/time ofLPS pretreatment can significantly alleviate the inflammation in mouse model infected with methicillin-resistances Staphylococcus aureus, methicillin-sensitive S. aureus, Pseudomonas aeruginosa, or Escherichia coil compared with doses of 0.25 mg/kg/time, 1 mg/ kg/time, and 1.5 mg/kg/time. Conclusions： LPS pretreatment can alleviate the inflammation in mouse model and the optimal dose is 0.5 mg/kg/time, and meanwhile it does not damage organs＇ function.

Effect of retension sutures on abdominal pressure after abdominal surgery

To evaluate the effect of retention sutures on abdominal pressure and postoperative prognosis in abdominal surgery patients. Methods： This prospective cohort study included patients who were admitted to Daping Hospital from May 15, 2014 to October 11, 2014. A total of 57 patients were enrolled, including 18 patients in the ＂U＂ type retention suture group, 17 patients in the intermittent retention suture group, and 22 patients in non-retention suture group. The demographic data, clinical data and risk factors for abdominal wound dehiscence were recorded. The bladder pressure （IVP） was monitored preoperatively, intraoperatively, and four days postoperatively. Additionally, the incidence of abdominal wound dehiscence and infection 14 days after the operation was recorded. Results： During the operation, the IVP decreased and then increased; it was at its lowest I h after the start of the operation （5.3 mmHg _＋ 3.2 mmHg） and peaked after tension-reducing （8.8 mmHg _＋ 4.0 mmHg）. The IVP values in the ＂U＂ type retention suture group and intermittent retention suture group were higher than in the non-retention suture group 4 days after operation （p 〈 0.005）. The Visual Analogue Scale （VAS） pain scores were 3.9 ~ 2.2, 3.8 ~ 2.0, and 3.0 _＋ 1,0 in the retention suture group, intermittent retention suture group and non-retention suture group, respectively. The VAS pain scores in the ＂U＂ type tension-reducing group and intermittent tension-reducing group were higher than in the non-tension-reducing group （p 〈 0,005）. Conclusion： Although retention sutures may reduce the incidence of postoperative wound dehiscence in abdominal surgery patients, they can increase the IVP and postoperative pain.