Flap perfusion of superficial split flap design for guided bone regeneration: A case report with ultrasonography.

[BACKGROUND] Effective flap management is crucial for successful bone regeneration procedures. Traditional flap release has been performed by the deep split design; recently, the superficial split design revives for its proposed anatomical and biomechanical advantages. To understand the risk of this new flap management design on flap vitality, the aim of this case report is to investigate the perfusion of the flap with ultrasound.

[METHODS] A single patient with an edentulous ridge exhibiting a horizontal bone deficiency underwent a regenerative procedure utilizing the superficial split technique (Secured Anatomy-Driven Flap Extension [SAFE] technique). Ultrasonography assessments were conducted before the surgery (baseline [BL]) and at days (D) 3, 10, 21, and at 5 months (MO) post-surgery. They included brightness-mode and color velocity/power (CV/CP) at the buccal flap. CV and CP cine loops (videos) were recorded to assess tissue perfusion by surrogate. Three distinct regions of interest were selected, i.e., keratinized mucosa (KM), lining mucosa (LM), and muscle (M).

[RESULTS] KM perfusion (CV) increased significantly at D3, then decreased at D10 and D21. The 5MO value was insignificant from BL. LM perfusion non-significantly decreased at D3 and D10, and returned to BL at D21 and 5MO. Muscle perfusion showed a nonsignificant decreasing trend. CP showed nonsignificant changes post-surgery relative to BL for the three regions.

[CONCLUSION] Ultrasound could be able to longitudinally quantify post-surgery tissue perfusion with sufficient spatial resolution to assess KM, LM, and M separately. This pilot ultrasonography study may ease the concern that the superficial split flap design jeopardizes flap vitality.

[KEY POINTS] Preliminary ultrasound data suggested that the Secured Anatomy-Driven Flap Extension (SAFE) technique, based on the superficial split approach, does not jeopardize flap vitality. Ultrasound may be a valuable tool for monitoring oral wound healing and guiding treatment decisions.

[PLAIN LANGUAGE SUMMARY] Ultrasound imaging technology, being a superior modality for evaluating soft tissue characteristics and able to quantify blood perfusion, is becoming a promising research tool to study oral wound healing. This case report used dental ultrasound to monitor the blood flow of an oral wound for 5 months after a jawbone augmentation procedure. Ultrasound showed gum blood flow peaked at day 3 after the surgery and decreased exponentially until 5 months. Mucosa and muscle may have various blood perfusion recovery patterns than gum tissues that deserve further investigation.