Prospective study to analyse the efficiency of Acoustic Doppler v/s Colour Duplex Ultrasound in locating perforators for antero-lateral thigh flap in reconstructive head and neck surgery

Abstract

The anterolateral thigh (ALT) flap has become the universal workhorse for Head and Neck reconstruction. Being a perforator-based flap, accurate planning by preoperative perforator localisation is clearly beneficial. Acoustic Doppler (AD) and Colour Duplex Ultrasound (CDU) are the most practicable methods of localisation available. We designed a prospective study to analyse the correlation between preoperative localisation (by AD and CDU) and intraoperative findings, factoring in the advantages of using a high frequency probe for CDU. Thirty-three consecutive patients were analysed in a prospective, observational study. AD was first used to mark the perforator point and its distance measured from two anatomical landmarks, the Anterior Superior Iliac Spine (ASIS) and the 'Reference line' (a line joining ASIS with the superior patellar border). CDU was then carried out to mark the perforator position with two probes (9 and 14 MHz), and the above distances measured for both points. At surgery, the actual point of perforator entry was separately marked and the same two distances were measured. A note was also made of perforator characteristics such as size and flow rate. In 21/33 cases, there was a close concordance between pre- and intraoperative localisation (complete success). From the remaining 12 cases, the complete absence of perforator was found in one case, a small, unreliable perforator in 2 cases and a site disparity of > 2 cm between true and preop points in 9 cases. No significant advantages were found with either a high frequency probe or indeed for CDU over AD. AD is sufficient for effective perforator localisation and should be routinely employed to accurately plan the anterior incision. CDU can be employed in cases where AD is unconvincing.