Dimensions of perforator flaps on the lower leg depending on localization.

INTRODUCTION: The soleus perforator flap and the peroneal perforator flap could be alternatives to the radial forearm flap for head and neck reconstruction. However, their flap dimensions remain unknown. This study aims to determine the dimensions of both flaps and allow preoperative planning for reconstruction based on clinical parameters. MATERIALS & METHODS: Computed tomography records of 296 patients dated from 2009 through 2019 were retrospectively analyzed. Virtual three-dimensional flap models of the soleus perforator flap and peroneal perforator flap were aligned to segmented leg models, and flap thickness and volume were determined. Associations of flap thickness and volume with clinical parameters were evaluated, and a calculation method was derived. RESULTS: The soleus perforator flap had an average thickness of 8.7 mm (4.8 mm) and an average volume of 0.9 cm³ (0.5 cm³) per square centimeter surface area. The peroneal perforator flap had an average thickness of 6.4 mm (3.8 mm) and an average volume of 0.8 cm³ (0.4 cm³) per square centimeter surface area. The soleus perforator flap was thicker and more voluminous than the peroneal perforator flap (both p<0.001). For both flaps, leg circumference was the strongest predictor of flap thickness (ß=0.524, p<0.001 and ß=0.700, p<0.001, respectively) and flap volume (ß=0.535, p<0.001 and ß=0.712, p<0.001, respectively). CONCLUSION: Dimensions of the soleus perforator and the peroneal perforator flaps are similar to those of the radial forearm flap. Preoperative planning of flap dimensions, such as flap thickness and volume, can help the surgeons select the appropriate flap.

Spatial analyses of two color polymorphisms in an alpine grasshopper reveal a role of small-scale heterogeneity.

Discrete color polymorphisms represent a fascinating aspect of intraspecific diversity. Color morph ratios often vary clinally, but in some cases, there are no marked clines and mixes of different morphs occur at appreciable frequencies in most populations. This poses the questions of how polymorphisms are maintained. We here study the spatial and temporal distribution of a very conspicuous color polymorphism in the club-legged grasshopper Gomphocerus sibiricus. The species occurs in a green and a nongreen (predominately brown) morph, a green-brown polymorphism that is common among Orthopteran insects. We sampled color morph ratios at 42 sites across the alpine range of the species and related color morph ratios to local habitat parameters and climatic conditions. Green morphs occurred in both sexes, and their morph ratios were highly correlated among sites, suggesting shared control of the polymorphism in females and males. We found that in at least 40 of 42 sites green and brown morphs co-occurred with proportions of green ranging from 0% to 70% with significant spatial heterogeneity. The proportion of green individuals tended to increase with decreasing summer and winter precipitations. Nongreen individuals can be further distinguished into brown and pied individuals, and again, this polymorphism is shared with other grasshopper species. We found pied individuals at all sites with proportions ranging from 3% to 75%, with slight, but significant variation between years. Pied morphs show a clinal increase in frequency from east to west and decreased with altitude and lower temperatures and were more common on grazed sites. The results suggest that both small-scale and large-scale spatial heterogeneity affects color morph ratios. The almost universal co-occurrence of all three color morphs argues against strong effects of genetic drift. Instead, the data suggest that small-scale migration-selection balance and/or local balancing selection maintain populations polymorphic.