International Journal of Surgery Does a muscle flap accelerate wound healing of gastric wall defects compared with an omental flap?  Masashi Hishida, Kazuhiro Toriyama, Shunjiro Yagi, Katsumi Ebisawa, Tsuyoshi Morishita, Keisuke Takanari, Yuzuru Kamei  International Journal of Surgery  Volume 18, Pages 41-47 (June 2015) DOI: 10.1016/j.ijsu.2015.03.022 Copyright © 2015 Terms and Conditions

Fig. 1 Surgical techniques. a, The centre of the anterior wall of the stomach was perforated between the fundus and body (arrow). G: gastric wall, O: omentum, P: pancreas. b, The muscle flap was elevated and transposed to the gastric wall defect. The tip of flap was folded, and the fascial side was affixed to the defect. M: right rectus abdominis muscle, MF: muscle flap. c, The omental flap was transposed to the gastric wall defect. The omental flap was fixed to the stomach perpendicular to the long axis (asterisk). International Journal of Surgery 2015 18, 41-47DOI: (10.1016/j.ijsu.2015.03.022) Copyright © 2015 Terms and Conditions

Fig. 2 Gross examination on day 6. a Muscle group, showing a shallow lesion filled with mucosal tissue. A deep ulcer defect appears as a small dimple (arrow). b Omentum group, showing a shallow lesion filled with mucosal tissue. Ulcer depth has decreased (arrow). International Journal of Surgery 2015 18, 41-47DOI: (10.1016/j.ijsu.2015.03.022) Copyright © 2015 Terms and Conditions

Fig. 3 Haematoxylin and eosin staining of the muscle group (a, c, e, g) and the omentum group (b, d, f, h) on day 3 (a, b), 5 (c, d), 7 (e, f) and 60 (g, h). a Granulation tissue has developed at the edge of defect and surrounding the fascia. b Extensive inflammatory cell infiltration is dominated by polymorphonuclear leucocytes and macrophages at the centre of the defect. c The granulation tissue at the mucosal edges has fused in the centre of the defect on the fascia. d Granulation tissue has proliferated to fill the defect. e The mucosal epithelial layer shows stratified villi completely covering the defect. f Mucosal oedema has decreased significantly, and stratified villi have completely covered the defect. g Irregular villi are observed. Scattered fundic glands are seen deep in the regenerate mucosa. h Many elongated well-developed villi were observed, while deep in the mucosa many fundic glands are seen. International Journal of Surgery 2015 18, 41-47DOI: (10.1016/j.ijsu.2015.03.022) Copyright © 2015 Terms and Conditions

Fig. 4 Numbers of vascular lumina in the centre of the defect. In the muscle group, the number of vascular lumina peaked on day 5 and decreased gradually thereafter. In the omentum group, the number of vascular lumina peaked on day 5 and then decreased slowly thereafter, becoming essentially constant by day 10. International Journal of Surgery 2015 18, 41-47DOI: (10.1016/j.ijsu.2015.03.022) Copyright © 2015 Terms and Conditions

Fig. 5 Masson trichrome staining of the muscle group (a, c, e) and the omentum group (b, d, f) on day 7 (a, b), 21 (c, d) and 60 (e, f). a Granulation tissue is being replaced gradually by scar tissue. b Granulation tissue is being replaced gradually by scar tissue. c Scar tissue persists in the submucosa. d Scar tissue has been replaced peripherally by adipose tissue. e Scar tissue persists. f Regenerated muscularis mucosae and muscular layer are observed at the edge. International Journal of Surgery 2015 18, 41-47DOI: (10.1016/j.ijsu.2015.03.022) Copyright © 2015 Terms and Conditions

Fig. 6 Immunohistochemical staining on day 4 of the muscle group (a, c, e) and the omentum group (b, d, f) showing the expression of PCNA (a, b), FGF-2 (c, d) and VEGF (e, f). a PCNA-positive cells are seen mainly surrounding the fascia. b PCNA-positive cells are seen mainly in granulation tissue. c Numbers of FGF-2-positive cells are increased in the area of the fascia. d Numbers of FGF-2-positive cells are increased in granulation tissue at the centre of the defect. e Numbers of VEGF-positive cells are increased in the area of the fascia. f Many strongly VEGF-positive cells are densely present in the granulation tissue at the centre of the defect. International Journal of Surgery 2015 18, 41-47DOI: (10.1016/j.ijsu.2015.03.022) Copyright © 2015 Terms and Conditions

Fig. 7 Immunohistochemical staining on day 10 of the muscle group (a, c, e) and the omentum group (b, d, f) showing the expression of PCNA (a, b), FGF-2 (c, d) and VEGF (e, f). With the defect now completely covered, numbers of PCNA-positive cells are decreasing gradually in muscle (a) and omentum (b) groups. c With the defect now re-epithelialised, numbers of FGF-2-positive cells are decreasing gradually in the area of the fascia. d Numbers of FGF-2-positive cells are decreasing gradually in the granulation tissue at the centre of the defect. FGF-2-positive cells are seen mostly surrounding blood vessels. e With the defect now re-epithelialised, numbers of VEGF-positive cells have decreased considerably in the area of the fascia; some endothelial cells remain positive. f Numerous VEGF-positive cells are observed, though the number of positive cells has decreased in granulation tissue. International Journal of Surgery 2015 18, 41-47DOI: (10.1016/j.ijsu.2015.03.022) Copyright © 2015 Terms and Conditions