The use of basic fibroblast growth factor to improve vocal function: A systematic review and meta-analysis

ObjectivesThis systematic review and meta-analysis examines if intralaryngeal injection of basic fibroblast growth factor 2 (FGF2) can improve voice outcomes in those with vocal disability. DesignA Systematic review of original human studies reporting voice outcomes following intra-laryngeal injection of basic fibroblast growth factor 2 in those with vocal dysfunction. Databases searched were Medline (1946-July 2022), Embase (1947-July 2022), Cochrane database and Google Scholar. SettingSecondary or tertiary care centres that undertook the management of voice pathology Hospital. ParticipantsInclusion criteria were original human studies reporting voice outcome measurements following intralaryngeal injection of FGF2 to treat vocal fold atrophy, vocal fold scarring, vocal fold sulcus or vocal fold palsy. Articles not written in English, studies that did not include human subjects and studies where voice outcome measures were not recorded before and after FGF2 injection were excluded from the review. Main Outcome MeasuresThe primary outcome measure was maximum phonation time. Secondary outcome measures included acoustic analysis, glottic closure, mucosal wave formation, voice handicap index and GRBAS scale. ResultsFourteen articles were included out of a search of 1023 and one article was included from scanning reference lists. All studies had a single arm design without control groups. Conditions treated were vocal fold atrophy (n = 186), vocal cord paralysis (n = 74), vocal fold fibrosis (n = 74) and vocal fold sulcus (n = 56). A meta-analysis of six articles reporting on the use of FGF2 in patients with vocal fold atrophy showed a significant increase of mean maximum phonation time of 5.2 s (95% CI: 3.4-7.0) at 3-6 months following injection. A significant improvement in maximum phonation time, voice handicap index and glottic closure was found following injection in most studies assessed. No major adverse events were reported following injection. ConclusionsTo date, intralaryngeal injection of basic FGF2 appears to be safe and it may be able to improve voice outcomes in those with vocal dysfunction, especially vocal fold atrophy. Randomised controlled trials are needed to further evaluate efficacy and support the wider use of this therapy.