{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,23]],"date-time":"2026-09-23T21:00:57Z","timestamp":1790197257366,"version":"4.1.0"},"reference-count":16,"publisher":"MDPI AG","issue":"12","license":[{"start":{"date-parts":[[2025,12,11]],"date-time":"2025-12-11T00:00:00Z","timestamp":1765411200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Toxins"],"abstract":"<jats:p>Signs of aging in the upper face arise from multimodal changes in facial anatomy, contributing to concerns such as eyebrow ptosis and forehead lines. While neurotoxin injections are widely used to address these lines, the anatomical variability of the frontalis muscle presents procedural challenges. This retrospective analysis aimed to introduce and preliminarily evaluate a structured injection pattern for forehead treatment, developed with attention to the biomechanics of upper facial musculature. A total of 24 patients (mean age 42.5 \u00b1 9.1 years) treated with a standardized injection scheme using letibotulinumtoxinA were included. All subjects also received concomitant glabellar treatment. The protocol incorporated identification of the line of convergence and targeted injections at defined points to balance elevation, optimize muscular activity, and minimize the risk of eyebrow descent. Forehead line severity was assessed at rest and during animation, and three-dimensional surface imaging was used to quantify vertical skin displacement. At baseline, 79.2% of patients presented with severe dynamic forehead lines, and 29.1% exhibited severe static lines. After two weeks, 62.5% showed no dynamic lines and 41.7% showed no static lines. All subjects demonstrated a \u22651-point improvement in dynamic line severity, with 87.5% achieving a \u22652-point improvement. For static lines, 95.8% achieved a \u22651-point improvement and 20.8% showed a \u22652-point improvement after two weeks. The mean dosage was 17.8 \u00b1 0.7 U. Two patients (8.3%) required a touch-up, and no adverse events were observed. These findings suggest that this structured injection approach may offer a consistent method for addressing forehead lines; however, the results should be interpreted within the limitations of a small, uncontrolled retrospective series. Prospective controlled studies with larger populations are needed to further validate the technique.<\/jats:p>","DOI":"10.3390\/toxins17120594","type":"journal-article","created":{"date-parts":[[2025,12,11]],"date-time":"2025-12-11T15:43:43Z","timestamp":1765467823000},"page":"594","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["Pilot Retrospective Evaluation of a Balancing and Optimizing Injection Pattern for the Frontalis Muscle Using LetibotulinumtoxinA"],"prefix":"10.3390","volume":"17","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-6994-8877","authenticated-orcid":false,"given":"Konstantin","family":"Frank","sequence":"first","affiliation":[{"name":"Department of Plastic, Hand and Reconstructive Surgery, University Hospital Regensburg, 93053 Regensburg, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2454-2499","authenticated-orcid":false,"given":"Lukas","family":"Prantl","sequence":"additional","affiliation":[{"name":"Department of Plastic, Hand and Reconstructive Surgery, University Hospital Regensburg, 93053 Regensburg, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Vanessa","family":"Brebant","sequence":"additional","affiliation":[{"name":"Department of Plastic, Hand and Reconstructive Surgery, University Hospital Regensburg, 93053 Regensburg, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Syed","family":"Haq","sequence":"additional","affiliation":[{"name":"Haq Medical Consultancy and AM Aesthetics, 10 Harley St, London W1G 9PF, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,12,11]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"427","DOI":"10.1152\/physrev.00061.2017","article-title":"Sarcopenia: Aging-Related Loss of Muscle Mass and Function","volume":"99","author":"Larsson","year":"2019","journal-title":"Physiol. Rev."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"213","DOI":"10.1007\/s00266-006-0024-9","article-title":"Structural Aging: The Facial Recurve Concept","volume":"31","author":"Buthiau","year":"2007","journal-title":"Aesthetic Plast. Surg."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"NP1208","DOI":"10.1093\/asj\/sjab202","article-title":"Understanding Facial Muscle Aging: A Surface Electromyography Study","volume":"41","author":"Cotofana","year":"2021","journal-title":"Aesthetic Surg. J."},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Gonzalez-Freire, M., de Cabo, R., Studenski, S.A., and Ferrucci, L. (2014). The Neuromuscular Junction: Aging at the Crossroad between Nerves and Muscle. Front. Aging Neurosci., 6.","DOI":"10.3389\/fnagi.2014.00208"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"NP531","DOI":"10.1093\/asj\/sjad009","article-title":"Multimodal Analyses of the Aging Forehead and Their Clinical Implications","volume":"43","author":"Alfertshofer","year":"2023","journal-title":"Aesthetic Surg. J."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"1625","DOI":"10.1111\/jocd.14133","article-title":"Respecting Upper Facial Anatomy for Treating the Glabella with Neuromodulators to Avoid Medial Brow Ptosis-A Refined 3-Point Injection Technique","volume":"20","author":"Cotofana","year":"2021","journal-title":"J. Cosmet. Dermatol."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"218","DOI":"10.18502\/jovr.v15i2.6740","article-title":"Techniques of Eyebrow Lifting: A Narrative Review","volume":"15","author":"Karimi","year":"2020","journal-title":"J. Ophthalmic Vis. Res."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"85","DOI":"10.1097\/IOP.0000000000001178","article-title":"The Relationship Between Eyebrow and Eyelid Position in Patients With Ptosis, Dermatochalasis and Controls","volume":"35","author":"Sinha","year":"2019","journal-title":"Ophthalmic Plast. Reconstr. Surg."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"594","DOI":"10.1097\/SCS.0000000000004301","article-title":"Eyebrow Position and Shape Favored by Korean Women","volume":"29","author":"Jung","year":"2018","journal-title":"J. Craniofac. Surg."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"1155","DOI":"10.1097\/PRS.0000000000006756","article-title":"The Bidirectional Movement of the Frontalis Muscle: Introducing the Line of Convergence and Its Potential Clinical Relevance","volume":"145","author":"Cotofana","year":"2020","journal-title":"Plast. Reconstr. 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Dermatol."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"NP962","DOI":"10.1093\/asj\/sjad151","article-title":"Use of LetibotulinumtoxinA for Aesthetic Treatment of Asians: A Consensus","volume":"43","author":"Liu","year":"2023","journal-title":"Aesthetic Surg. J."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"239","DOI":"10.1097\/PSN.0000000000000585","article-title":"Consensus Recommendations for Treatment of the Upper Face with LetibotulinumtoxinA","volume":"44","author":"Choi","year":"2024","journal-title":"Plast. Aesthet. Nurs."}],"container-title":["Toxins"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-6651\/17\/12\/594\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,12,12]],"date-time":"2025-12-12T09:44:05Z","timestamp":1765532645000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-6651\/17\/12\/594"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,12,11]]},"references-count":16,"journal-issue":{"issue":"12","published-online":{"date-parts":[[2025,12]]}},"alternative-id":["toxins17120594"],"URL":"https:\/\/doi.org\/10.3390\/toxins17120594","relation":{},"ISSN":["2072-6651"],"issn-type":[{"value":"2072-6651","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,12,11]]}}}