Echo-guided soft tissue harvesting: A novel approach identifying tissue thickness, density, vascularisation and a safe harvesting zone in the palatal region

Abstract

Purpose: To utilise high-frequency ultrasound echo intensity as a method for identifying a safe harvesting zone and assessing tissue thickness, density and vascularisation in the palatal region for soft tissue harvesting. Materials and methods: Four consecutive patients requiring soft tissue augmentation were recruited. Optical scans were taken and imported into design software, where customised guides were developed based on the patient's palatal anatomy and the harvesting zone. The guides were tailored to fit the shape of the ultrasound probe. They were 3D printed and allowed for a standardised examination of the palate, the identification of a safe harvesting zone and the evaluation of tissue thickness, quality and vascularisation using high-frequency ultrasound. Following these steps and using an echo-harvesting guide, a de-epithelialised free gingival graft was obtained, ensuring preservation of the main vascular flow while avoiding fatty or glandular tissues. Results: In all four cases, high-frequency ultrasound scans were successfully obtained and the mean measured soft tissue thickness increased from 3.2 mm (anterior) to 6.0 mm (posterior), with a mean transversal increase from 0.9 to 6.0 mm. Ultrasound imaging revealed a layer of hypoechogenic fatty/glandular tissue located 3 to 4 mm beneath the epithelial layer. Using colour Doppler analysis, the vascular flow was identified and mapped to help design a safe harvesting zone. The tissue density, evaluated using a grayscale analysis, showed hypoechogenicity corresponding to fatty/glandular tissues and areas with blood vessels, whereas dense connective tissue appeared isoechoic. This differentiation allowed for precise localisation of the safe harvesting zone, an optimal zone for connective tissue harvesting, while ensuring that regions with higher fat/glandular content and/or large vascular structures were avoided. Conclusion: The echo-guided harvesting approach is a promising technique for soft tissue palatal harvesting, enabling clinicians to identify a standardised safe zone away from major blood vessels when assessing tissue quality and quantity. This approach enhances surgical precision and control, and facilitates preoperative planning for alternative treatments when graft size or tissue quality or quantity are inadequate due to proximity to the greater palatine artery. It is crucial to note that a learning curve is required to interpret the obtained images accurately and integrate this tool into daily clinical practice.