Endoscopic Sealing With a Polyglycolic Acid Sheet for Restoration of Vocal Fold Mucosa in Dogs

Application of polyglycolic acid sheets and basic fibroblast growth factor to prevent esophageal stricture after endoscopic submucosal dissection in pigs

BACKGROUND

Endoscopic submucosal dissection (ESD) has been the first-line treatment for early-stage esophageal cancer. However, it often causes postoperative stricture in cases requiring wide dissection. Basic fibroblast growth factor (bFGF) reportedly has anti-scarring effects during cutaneous wound healing. We hypothesized that suppressing myofibroblast activation will prevent stricture after esophageal ESD.

METHODS

We resected a complete porcine esophagus circumference section by ESD. To investigate the preventive effect of bFGF on esophageal stricture formation after ESD, we endoscopically applied bFGF-soaked poly-glycolic acid (PGA) sheets onto the wound bed after ESD and fixed them by spraying fibrin glue (PGA + bFGF group), PGA sheets alone onto the wound bed and fixed them by spraying fibrin glue (PGA group), or nothing (control group). After removing the esophagus on day 22, we evaluated the mucosal constriction rate.

RESULTS

Compared with those in the control group, esophageal stricture was significantly reduced in the PGA + bFGF group, and the areas stained with α-SMA and calponin-1 antibodies were significantly inhibited in the PGA + bFGF and PGA groups. The thickness of the fibrous layer in the PGA + bFGF group was uniform compared to that of the other groups. Thus, PGA + bFGF inhibited the development of unregulated fibroblasts in the acute phase, leading to uniform wound healing.

CONCLUSIONS

Stenosis after esophageal ESD is related to fibrosis in the acute phase. Administration of PGA and bFGF suppresses myofibroblast activation in the acute phase, thereby preventing esophageal constriction in pigs.

Factors affecting polyglycolic acid sheet engraftment success for covering mucosal defects from head and neck surgery

BACKGROUND

Polyglycolic acid (PGA) sheets have been used with fibrin glue to cover extensive mucosal defects in oral and pharyngeal surgery; however, the sheets can fall off before wound healing is completed. Hence, prolonged fasting is often recommended in such patients. However, there are few studies on the factors that shape PGA sheet engraftment. We studied sheet engraftment rates considering these factors.

METHODS

All consecutive cases of oral surgery in 2013-21 in which the defect was covered with fibrin glue and Neoveil® or Neoveil Nano® PGA sheets were identified. The loss of all sheets was defined as an engraftment failure. Multiple logistic regression analysis was conducted to identify whether the PGA-sheet type, application site, defect size and postoperative fasting duration predicted engraftment.

RESULTS

Overall, 137 patients were identified (mean age, 73 years; 57% male). The surgeries were conducted with Neoveil® in 66% of the patients; the most common site was the buccal mucosa (25%), and the mean defect size and fasting duration were 709 mm2 and 4 days, respectively. The engraftment rate was 76%. Neoveil Nano® PGA sheets were associated with a 2.8-fold better engraftment rate than Neoveil® (univariate: 87 vs. 70%, P = 0.032; multivariate: 95% confidence intervals = 1.067-7.410, P = 0.036). Other variables, including fasting duration, were not predictive of engraftment.

CONCLUSIONS

This is the largest case series of patients with head and neck cancer who underwent fibrin glue-PGA sheet defect coverage. The fasting duration did not influence engraftment. Therefore, early oral intake is not contraindicated in such patients.

Methodological Approaches for Vocal Folds Experiments in Laryngology: A Scoping Review

OBJECTIVE

The aim of this study was to describe the methodological approaches adopted in experimental researches in laryngology intervention studies.

METHODS

The study was performed as a scoping review using the electronic databases Medline (PubMed), Web of Science, Embase, BioMed Central and SCOPUS. These databases were manually searched from 1995 (or its inception) until the most recently published articles in June 2022. The inclusion criteria were as follows: a) studies performed with animal models in voice and/or larynx therapy, intervention and/or surgery; b) studies with participant populations composed with animals; c) studies containing original research; d) studies performed with at least one objective measurement for treatment and or intervention; e) studies reporting at least one method of larynx intervention; and f) publications written in English, Spanish or Portuguese. The exclusion criteria were as follows: a) studies considering without any objective intervention and or treatment; b) studies without animal models; and c) studies that reviewed articles or books. These criteria were set to increase inter-study comparability.

RESULTS

There were found 26 studies that showed that in experimental laryngology. There were retrieved four main characteristics in the retrieved studies. It was observed five major groups of experimental models used for assessing vocal folds: dog (38.5%), rat/mouse (23,1%), pig (23.1%), rabbit (19.2%), human (11.5%), and sheep (3.8%). In addition, three characteristics were observed: sample (up to 20 subjects 88.5%), type of surgery/intervention (100%) and duration (up to 30 days 61.5%).

CONCLUSION

In experimental laryngology, the state of the art is grounded on mainly in dog, rat and pig in vocal folds assessment. Up to 20 subjects, surgery/intervention and experimental trial lasting no more than 30 days are frequent methodological approaches in this research field.