Scar tissue at the recipient site reduces the sensory recovery in myocutaneous flaps

In 1993 it was reported that sensory nerve axons enter myocutaneous flaps from all sides of the wound bed through empty perineural tubes, suggesting that small flaps (because less tissue must be reinnervated) and old flaps (because the regenerating process should be completed) would have the best sensation. However, sensory recovery is correlated with neither the flap size nor their age. Since all 16 flaps in this study were placed on significantly traumatized limbs, scar formation should hinder sprouting axons from entering the flap; the present study was performed to test this hypothesis. The sensation of 16 myocutaneous flaps (group A) placed in a nontraumatized wound bed was compared to that of patients in a previous study (group B). All 32 flaps were tested for pin-prick, hot, cold, 30-Hz, 256-Hz vibration, constant touch, moving two-point discrimination, and static two-point discrimination. The results were rated as follows: 2 points for a modality being present all over the flap, 1 for its partial or dull presence, and 0 for no sensation. The elapsed time following surgery was 1.10 –5.40 years in group A and 1.50–8.20 years in group B. Patients in group A scored a mean score of 8.0±2.1 points (4–11) and those in group one of B 5.9± 4.8 (0–13). There was a significant correlation between score and flap age in group A but not in group B; there was no correlation in either group between score and the flap size. Our findings suggest that scar formation is detrimental to the capacity for sensory recovery in myocutaneous flaps. Maximum scar tissue excision is recommended, especially since sensory recovery is not less than in large flaps.     

Comparison of Asymmetry in Cerebral Blood Flow Between Brain Hemispheres Using Digital Subtraction Angiography

BACKGROUND AND PURPOSE: Recently, endovascular techniques have gained significant therapeutic potential for both treatment and prevention of stroke. Cerebral angiography, which is an essential component of these procedures, has been used to provide morphological information regarding condition of blood vessels. In this study, we propose to determine the possibility of acquiring information regarding cerebral blood flow (CBF) in addition to morphologic information from data routinely available during angiography. METHODS: Digital subtraction angiography sequences were obtained for eight patients having occlusive disease in internal carotid artery (ICA) territories. Two regions-of-interest (ROIs) corresponding to the two brain hemispheres on AP view were delineated. For each image, the average pixel value within each ROI was calculated and used to generate time-density curves. Indices obtained from each curve were compared with each other and with the results obtained from the single photon emission computed tomography (SPECT) studies performed a pre- or postangiography procedure. RESULTS: Comparison between ICA stenosis and cerebral perfusion measurements revealed that cerebral perfusion deficit can be independent of arterial occlusive disease. The indices obtained from the time-density curves exhibit a correlating trend with the results from SPECT studies. However, lack of sufficient sample data prevented any meaningful statistical analysis to be conducted. CONCLUSIONS: We have developed a technique for utilizing the angiographic data for the important task of routinely and easily measuring CBF. Availability of CBF measurements during cerebral angiography may favorably impact upon the appropriate use of endovascular procedures and potentially contribute to the reduction of morbidity and mortality associated with stroke.     

An inventory-location optimization model for equitable influenza vaccine distribution in developing countries during the COVID-19 pandemic

The addition of other respiratory illnesses such as flu could cripple the healthcare system during the coronavirus disease 2019 (COVID-19) pandemic. An annual seasonal influenza vaccine is the best way to help protect against flu. Fears of coronavirus have intensified the shortage of influenza shots in developing countries that hope to vaccinate many populations to reduce stress on their health services. We present an inventory-location mixed-integer linear programming model for equitable influenza vaccine distribution in developing countries during the pandemic. The proposed model utilizes an equitable objective function to distribute vaccines to critical healthcare providers and first responders, elderly, pregnant women, and those with underlying health conditions. We present a case study in a developing country to exhibit efficacy and demonstrate the optimization model’s applicability.     

Obliteration of the frontal sinus with the pericranial flap

A host of autogenous and synthetic materials ranging from free fat, muscle, and bone to methylmethacrylate, hydroxyapatite cement, and glass beads have been used to obliterate the frontal sinus. These materials carry an increased risk of donor-site morbidity, as well as the risk of resorption, infection, and local inflammatory reactions. The pericranial flap is a local flap that can be used to obliterate small- and medium-sized frontal sinuses. This vascularized flap is easily and quickly harvested, and it avoids the morbidity associated with free-fat and cancellous bone grafts. Its ease of harvest, vascularity, and low complication rate make the pericranial flap an excellent alternative for frontal sinus obliteration.