PMC9751053_01
Timeline of the procedures. Scar was removed and the photosynthetic scaffold was implanted to cover the newly generated wound (day 0). During the first 7 days after surgery, implanted photosynthetic scaffold was illuminated. On day 21 after implantation, a split-thickness autograft was surgically fixed on top of the previously implanted photosynthetic scaffold. At month 16, a vacuum massage therapy was applied to the recovered area. Patient was monitored for a total of 17 months after the first surgery.
fbioe-10-1004155-g001.jpg
PMC9751053_01_fbioe-10-1004155-g001.jpg
F1
An overall timeline of the procedures is shown in Figure 1.
Surgical procedures. Scar removal (A): edges were marked prior to resection (A1), and a complete scar excision was performed (A2-3), exposing the subcutaneous adipose tissue and the final size of the defect (A4). Scaffold implantation (B): five sheets of photosynthetic scaffold (5 x 5 cm each) were required to cover the wound (B1), being cut-fitted, and fixed to the defect with non-absorbable sutures (B2-3). Finally, scaffolds were covered with a sterile dressing and the illumination device was placed on top (B4). Autograft (C): 21 days after implantation, no signs of rejection, inflammation or infection were detected in the scaffolds, and a loss of the characteristic initial green color of the scaffold was observed (C1). After removal of the silicon layer (C2), an autograft was implanted (C3) and negative wound therapy was applied (C4). Scale bar represents 5 cm.
fbioe-10-1004155-g002.jpg
PMC9751053_01_fbioe-10-1004155-g002.jpg
F2
Complete excision of the burn scar contracture (Figure 2A1), including the central chronic ulcer, was performed with an electrosurgical unit, reaching the healthy adipose tissue of the subcutaneous plane (Figure 2A2). Detail of the removed burn scar tissue is shown in Figure 2A3. Due to the release of tension on the surrounding healthy skin, the size of the wound increased from 11 x 9 cm (~80 cm2) to 18 x 10 cm (~134 cm2), allowing a fully functional flexo-extension of the elbow (Figure 2A4). After complete removal of the scar, the wound bed was washed with sterile saline solution, while photosynthetic scaffolds were measured and cut to fit and cover the defect (Figure 2B1). Next, scaffolds were fixed with nylon 4/0 non-absorbable monofilament sutures (Ethilon , Johnson&Johnson, NJ, USA) to the wound edges and between them, leaving the scaffold in direct contact with the wound bed (Figures 2B2,B3). Finally, the illumination device was turned on (Figure 2B4) as previously described. Information regarding the patient's perception of pain, itch, burning, smell, and light annoyance after the surgery is included in Supplementary Figure S2. The absence of signs of inflammation or infection in the surrounding healthy skin enabled the team to proceed with the skin autograft surgery at day 21 (Figures 2C1,C2). Sutures and the silicone layer of the photosynthetic scaffold were removed, showing that the remaining collagen scaffold was correctly integrated to the wound bed (Figure 2C2). After washing with sterile saline solution, a 0.2 mm thick partial thickness skin autograft was implanted on top of the previously implanted scaffold (Figure 2C3). Finally, a paraffin gauze dressing was overlaid, and a negative-pressure wound therapy dressing (Renasys , Smith & Nephew, Hull, England) was positioned over the intervened area, which was maintained for 5 days at -120 mmHg (Figure 2C4).
Mechanical and biophysical characterization of the skin in the regenerated area. (A) Hydration parameters of the skin. The hydration percentage, measured with a corneometer, is shown on the left, comparing both healthy skin from left arm with regenerated skin from right arm. The trans epidermal water loss (TEWL) is reported on the right, comparing both healthy skin from control arm with regenerated skin from right arm. Four measurements were made at either arm in each timepoint. The effect of the vacuum massage treatment on right arm can be seen for both parameters measured. Left arm values are the average of measurements at two different timepoints. ns, not significant differences; *p < 0.0001, one-way ANOVA. (B) Mechanical evaluation of the skin. Consecutive deformation cycles were performed on the skin using a cutometer, to assess for elastic properties of both healthy and regenerated skin. The measurements were repeated after the vacuum therapy. R parameters were calculated, and a qualitative improvement index is shown, stating if parameters improved on the right arm after the vacuum therapy sessions, relative to values obtained for the left arm.
fbioe-10-1004155-g003.jpg
PMC9751053_01_fbioe-10-1004155-g003.jpg
F3
Corneometry studies, performed to evaluate hydration of the skin, showed basal values of 46.5 +- 3.3% and 56.5 +- 1.8% for healthy and regenerated tissue respectively, which was not significantly affected by the vacuum massage sessions, maintaining a value of 46 +- 6.6% (Figure 3A, left). In contrast, trans epidermal water loss (TEWL) showed significant differences between the control and regenerated area, with basal values of 7.4 +- 0.26 g m-2 h-1 and 3.5 +- 0.1 g m-2 h-1 respectively, but such difference was reverted after vacuum massage therapy, reaching a value of 7.8 +- 0.35 g m-2 h-1 (Figure 3A, right). Values for the left arm (control) corresponds to the average data of measurements performed at two time points in the same healthy arm (Figure 3A). Measurements revealed poor flexibility characteristics of the regenerated area, relative to the control arm (Figure 3B). Values directly related to skin elasticity (R2, R5 and R7), also approached values closer to control after the vacuum therapy sessions, or maintained its value in the case of R7, emphasizing the mechanical improvement obtained with the directed treatment on the regenerated area (Figure 3B).
Qualitative outcome and self-evaluation. (A) Long-term photograph of the complete integration of photosynthetic scaffold and autologous split-thickness skin graft after 17 months. Detail of the skin graft outcome, and qualitative pinch-test performed in the treated area. Photographs show the entire arm achieving full-range flexion and extension, underscoring the gain in flexibility and elasticity in the regenerated area. Scale bars represent 5 cm. (B) A personal survey instrument to measure the patient-perceived outcome of the surgical procedure was applied at the month 17. The results reported in the three categories evaluated (appearance, symptoms and psychosocial) show an increased score in the self-perception of the injured area after the full treatment. An increased score in each category implies a better perception. No bar is observed in preoperative psychosocial survey, as SCAR-Q score was zero.
fbioe-10-1004155-g004.jpg
PMC9751053_01_fbioe-10-1004155-g004.jpg
F4
At month 17, a qualitative pinch test was performed on the regenerated skin, showing that the new tissue was flexible, allowing the patient to fully extend her arm (Figure 4A). Rasch transformed score. Results shows a highly positive patient s perception after the complete surgical and ambulatory procedures, i.e., 6.6-fold in appearance improvement, 3.1-fold in symptoms reduction and a response from 0 (worst) to 100 (best) score for the psychosocial perception (Figure 4B).