Quantifying postoperative recovery using wearable activity monitors following abdominal wall surgery: The AbTech trial.

PURPOSE: This work aimed to investigate the validity of wearable activity monitors (WAMs) as an objective tool to measure the return toward normal functional mobility following abdominal wall surgery. This was achieved by quantifying and comparing pre- and postoperative physical activity (PA). METHODS: A multicenter, prospective, observational cohort study was designed. Patients undergoing abdominal wall surgery were assessed for eligibility and consent for study participation was obtained. Participants were asked to wear a WAM (AX3, Axivity) on the wrist of their dominant hand at least 48 hours pre-operatively, for up to 2 weeks postop, and again after 6 months postop for 48 hours. RESULTS: A cohort of 20 patients were recruited in this validation study with a mean age of 47.3 ± 13.0 years. Postoperation, the percentage median PA (±IQR) dropped to 32.6% (20.1), whereas on day 14, PA had reached 64.6% (22.7) of the preoperative value providing construct validity. Activity levels at >6 months postop increased by 16.4% on an average when compared to baseline preoperative PA (p = 0.046). CONCLUSION: This study demonstrates that WAMs are valid markers of postoperative recovery following abdominal wall surgery. This was achieved by quantifying the reduction in PA postoperation, which has not been previously shown. In addition, this study suggests that abdominal wall surgery may improve the patient's quality of life via increased functional mobility at 6 months postop. In the future, this technology could be used to identify the patient and surgical factors that are predictors of outcome following abdominal wall surgery.

Pervasive wearable device for free tissue transfer monitoring based on advanced data analysis: clinical study report.

Free tissue transfer (FTT) surgery for breast reconstruction following mastectomy has become a routine operation with high success rates. Although failure is low, it can have a devastating impact on patient recovery, prognosis, and psychological well-being. Continuous and objective monitoring of tissue oxygen saturation (StO2) has been shown to reduce failure rates through rapid detection time of postoperative vascular complications. We have developed a pervasive wearable wireless device that employs near-infrared spectroscopy (NIRS) to continuously monitor FTT via StO2 measurement. Previously tested on different models, the results of a clinical study are introduced. Our goal for the study is to demonstrate that the developed device can reliably detect StO2 variations in a clinical setting: 14 patients were recruited. Advanced data analysis was performed on the StO2 variations, the relative StO2 gradient change, and the classification of the StO2 within different clusters of blood occlusion level (from 0% to 100% at 25% step) based on previous studies made on a vascular phantom and animals. The outcomes of the clinical study concur with previous experimental results and the expected biological responses. This suggests that the device is able to correctly detect perfusion changes and provide real-time assessment on the viability of the FTT in a clinical setting.

The Skin You Are In: Design-of-Experiments Optimization of Lipid Nanoparticle Self-Amplifying RNA Formulations in Human Skin Explants.

Messenger RNA (mRNA) is a promising tool for biotherapeutics, and self-amplifying mRNA (saRNA) is particularly advantageous, because it results in abundant protein expression and production is easily scalable. While mRNA therapeutics have been shown to be highly effective in small animals, the outcomes do not scale linearly when these formulations are translated to dose-escalation studies in humans. Here, we utilize a design of experiments (DoE) approach to optimize the formulation of saRNA lipid nanoparticles in human skin explants. We first observed that luciferase expression from saRNA peaked after 11 days in human skin. Using DoE inputs of complexing lipid identity, lipid nanoparticle dose, lipid concentration, particle concentration, and ratio of zwitterionic to cationic lipids, we optimized the saRNA-induced luciferase expression in skin explants. Lipid identity and lipid concentration were found to be significant parameters in the DoE model, and the optimized formulation resulted in ∼7-fold increase in luciferase expression, relative to initial 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP) formulation. Using flow cytometry, we observed that optimized formulations delivered the saRNA to ∼2% of the resident cells in the human skin explants. Although immune cells comprise only 7% of the total population of cells in skin, immune cells were found to express ∼50% of the RNA. This study demonstrates the powerful combination of using a DoE approach paired with clinically relevant human skin explants to optimize nucleic acid formulations. We expect that this system will be useful for optimizing both formulation and molecular designs of clinically translational nucleic acid vaccines and therapeutics.

A method to select patients for vertical scar or inverted-T pattern breast reduction.

Vertical scar breast reduction (VSBR) is an increasingly popular technique but can carry a high complication and revision rate. We evaluate our complication rate when selecting patients for VSBR or inverted-T breast reductions (ITBR). We looked at 133 consecutive primary bilateral breast reductions performed by a single consultant from 1998 to 2003 (23 incomplete records). VSBR (82 breasts) and ITBR (120 breasts) were performed, with glandular or superomedial pedicle transposition of the nipple-areola complex (NAC), or free nipple grafts (FNG) (18 breasts). The pattern of skin excision chosen was determined by the degree of skin shrinking required to achieve the correct vertical height of the new breast. If the measurement from the inframammary fold to the lower border of the new areola position was < 18 cm the patient underwent VSBR. We assessed complication and revision rates in each group. The complication rate (haematoma, infection, delayed healing, nipple/fat necrosis) in VSBR was 11%, in ITBR 23% (P<0.05). Revision rate was 2.4% in the VSBR and 3.3% in ITBR group. The VSBR had no problem scars, while the ITBR produced problem scars in 16% of operated breasts (P<0.001). We feel it is possible to reduce skin to 40-50% of its original length. Attempting a greater degree of shrinkage produces a high rate of revision surgery. We suggest a method of selection of technique by a reproducible measurement of the vertical skin reduction to produce a low complication rate and low revision rate.

Objective assessment of keloid scars with three-dimensional imaging: quantifying response to intralesional steroid therapy.

BACKGROUND: Treatment of keloid scars poses a significant challenge. Assessment of treatment response and research in this area depend on the availability of objective, accurate, and reproducible outcome measures. At present, scars are assessed using subjective grading systems, or with cumbersome investigations such as direct casting. The authors assessed the feasibility of objectively monitoring response to intralesional steroid treatment in routine clinical practice with quantitative three-dimensional imaging. METHODS: Scar volume was quantified using a validated three-dimensional speckle-pattern stereophotogrammetry before and for a minimum of 8 weeks after intralesional steroid therapy in 12 patients with keloid scars. RESULTS: Mean scar volume at the start of treatment was 0.73 +/- 0.701 cc (range, 0.12 to 2.15 cc); this was reduced to 0.14 +/- 0.302 cc (range, 0.007 to 1.08 cc) after monthly intralesional injections of triamcinolone acetate (p < 0.001; analysis of variance). The majority of patients achieved a greater than 50 percent response within 8 weeks of the start of therapy, but poor treatment response was noted and quantified in a minority of patients. CONCLUSIONS: Three-dimensional stereophotogrammetry is a rapid and noninvasive method of scar volume assessment that could allow accurate and objective monitoring of treatment response to be incorporated into clinical practice. Therefore, it can be of considerable value in assessing treatment efficacy and evaluating new therapeutic strategies.