Critical biomechanical and clinical insights concerning tissue protection when positioning patients in the operating room: A scoping review.

An optimal position of the patient during operation may require a compromise between the best position for surgical access and the position a patient and his or her tissues can tolerate without sustaining injury. This scoping review analysed the existing, contemporary evidence regarding surgical positioning-related tissue damage risks, from both biomechanical and clinical perspectives, focusing on the challenges in preventing tissue damage in the constraining operating room environment, which does not allow repositioning and limits the use of dynamic or thick and soft support surfaces. Deep and multidisciplinary aetiological understanding is required for effective prevention of intraoperatively acquired tissue damage, primarily including pressure ulcers (injuries) and neural injuries. Lack of such understanding typically leads to misconceptions and increased risk to patients. This article therefore provides a comprehensive aetiological description concerning the types of potential tissue damage, vulnerable anatomical locations, the risk factors specific to the operative setting (eg, the effects of anaesthetics and instruments), the complex interactions between the tissue damage risk and the pathophysiology of the surgery itself (eg, the inflammatory response to the surgical incisions), risk assessments for surgical patients and their limitations, and available (including emerging) technologies for positioning. The present multidisciplinary and integrated approach, which holistically joins the bioengineering and clinical perspectives, is unique to this work and has not been taken before. Close collaboration between bioengineers and clinicians, such as demonstrated here, is required to revisit the design of operating tables, support surfaces for surgery, surgical instruments for patient stabilisation, and for surgical access. Each type of equipment and its combined use should be evaluated and improved where needed with regard to the two major threats to tissue health in the operative setting: pressure ulcers and neural damage.

Effect of laser therapy on expression of angio- and fibrogenic factors, and cytokine concentrations during the healing process of human pressure ulcers.

Objective: To evaluate the effect of laser irradiation at different wavelengths on the expression of selected growth factors and inflammatory mediators at particular stages of the wound healing process. Methods: Sixty-seven patients were recruited, treated, and analyzed (group A - 940 nm: 17 patients; group B - 808 nm: 18 patients; group C - 658 nm: 16 patients; group D - sham therapy: 17 patients). Patients received a basic treatment, including repositioning and mobilization, air pressure mattress and bed support surfaces, wound cleansing and drug therapy. Additionally, patients received laser therapy once a day, 5 times a week for 1 month in use of a semiconductor lasers (GaAlAs) which emitted a continuous radiation emission at separate wavelengths of 940 nm (group A), 808 nm (group B) and 658 nm (group C). In group D (sham therapy), laser therapy was applied in the same manner, but the device was off during each session (only the applicator was switched on to scan pressure ulcers using none coherent red visible light). Results: The positive changes in the measured serum (IL-2, IL-6 and TNF-α) and wound tissue (TNF-α, VEGF and TGFß1) parameters appeared to be connected only with the wavelength of 658 nm. The significant change in pro-inflammatory mediator levels [interleukin 2 (IL-2) with p=0.008 and interleukin 6 (IL-6) with p=0.016] was noticed after two weeks of laser therapy. In the other groups, the inflammation was also reduced, but the process was not as marked as in group C. Similarly, in the case of tumor necrosis factor (TNF-α) concentration, where after two weeks of treatment with irradiation at a wavelength of 658 nm, a rapid suppression was observed (p=0.001), whereas in the other groups, these results were much slower and not as obvious. Interestingly, again in the case of group C, the change in TNF-α concentration in wound tissue was most intensive (≈75% reduction), whereas the changes in other groups were not as obvious (≈50% reduction). After irradiation (658 nm), the VEGF expression increased significantly within the first two weeks, and then it decreased and maintained a stable level. In contrast, the TGFß1 activity remained level, but always higher in comparison to other groups Conclusions: The effective healing of pressure ulcers is connected with laser irradiation at a wavelength of 658 nm. We believe that this effect is related to the inhibition of inflammatory processes in the wound and stimulation of angiogenesis and fibroblast proliferation at this specific radiation (based both on concentration of interleukins and TNF-α serum level and VEGF, TGFß1, TNF-α activities in wound biopsies). Laser therapy at wavelengths of 940 and 808 nm does not significantly affect the above-mentioned repair processes, which explains its low effectiveness in the treatment of pressure ulcers.

Beware of the toilet: The risk for a deep tissue injury during toilet sitting.

A pressure injury (PrI) compromises quality of life and can be life-threatening. The fundamental cause of PrIs is sustained deformations in weight-bearing soft tissues, e.g., during prolonged sitting on inadequate surfaces such as a toilet seat. In nursing homes and geriatric facilities, patients need assistance using the restroom, and patients being left on the toilet for tens-of-minutes is a real-world scenario, unfortunately. Nevertheless, there are no published studies regarding sustained tissue loads during toilet sitting and their effects on tissue physiology. Here, the biomechanical and microcirculatory responses of the buttock tissues to toilet sitting were investigated using finite element modeling and cutaneous hemodynamic measurements, to explore the potential etiology of PrIs occurring on the toilet. We found that prolonged sitting on toilet seats involves a potential risk for PrI development, the extent of which is affected by the seat design. Additionally, we found that specialized toilet seat cushions are able to reduce this risk, by lowering instantaneous tissue exposures to internal stresses (by up to 88%) and maintaining reduced interface pressures. Furthermore, hemodynamic variables were altered during the toilet sitting; in particular, tcPO2 was decreased by 49% ± 7% (44 ± 2[mmHg] to 22 ± 4[mmHg]) during sitting. The current study confirms that investing in expensive PrI prevention (PIP) products is likely to be ineffective for an immobilized patient who is left to sit on a bare toilet seat for long times. This argument highlights the need for a holistic-care approach, employing PIP devices that span across the entire environment where bodyweight forces apply to tissues.

The natural medications for wound healing - Curcumin, Aloe-Vera and Ginger - do not induce a significant effect on the migration kinematics of cultured fibroblasts.

Curcumin, Aloe-vera and Ginger are popular natural medications (NMs) for treating wounds, however, the mechanisms by which these NMs apparently accelerate wound healing remain largely unknown. From a biomechanical perspective, it is specifically unclear whether fibroblast motility improves in the presence of any of these NMs. Here we use our recently developed quantitative high-precision automated assay for cell migration (Topman et al., 2012b) which is based on image processing of time lapse micrographs to determine whether kinematic parameters e.g. the maximum and average migration rates of en mass fibroblast colonies are influenced by treating the cells with the above NMs. We found no evidence that Curcumin, Aloe-vera and Ginger directly influence the en mass fibroblast migration kinematics in vitro post infliction of localized mechanical damage to the cultures. However, due to the complexity of a wound healing process in vivo, these NMs may still influence the healing through other pathways.