A Prospective Clinical Assessment of Anatomic Variability of the Submental Vascularized Lymph Node Flap

Purpose

The vascularized submental lymph node (VSLN) flap is an excellent option when deciding to pursue surgical treatment of lymphedema.  Unfamiliar vascular anatomy and variability in key anatomic structures have led many to avoid the use of this flap.  A detailed understanding of the anatomic variations related to the VSLN flap will allow for a safe and predictable flap harvest.   

Methods

Detailed vascular anatomy was prospectively collected for a consecutive series of VSLN flap transfers.  A classification system is described based on the frequency and occurrence of arterial and venous variations.  Arterial variation is described as related to the vessel coursing deep (A1), through (A2), or superficial (A3) to the submandibular gland.  Vein classification is based on a similar relationship (V1-V3) with the addition of a dual venous system (V4).  Other pertinent flap anatomic flap characteristics were also evaluated.  An a priori value of 0.05 was considered statistically significant.      

Results

Forty-two clinical cases of VSLN flap were prospectively evaluated.  Average arterial diameter was 2.8mm, while average vein diameter was 3.4mm.  Two arterial (A1 & A2) variations existed, while 4 venous (V1-V4) variations existed in all patients.  Overall, the A1 arterial course (74%) was found in a greater frequency as compared to the A2 course (26%).  The most common arteriovenous (AV) configuration occurred in 31% of patients (A1V1), followed by a divergent AV configuration (A1V3) in 21.4% of patients.  Other AV configurations existed in lesser frequency (A1V4/A2V3; 16.7%, A2V4; 7.1%, A1V2; 4.8%).  Flap harvest time was significantly longer when the A2 arterial course was found (p<0.01).     

Conclusions

Understanding the various anatomic variations of the VSLN flap will allow for more efficient and reproducible flap harvest.  Consistent vascular variability exists as related to the submandibular gland.  The most common AV configuration is seen with the main vessels being present deep to the submandibular gland just below the mandibular border.  Overall, most AV configurations are found with divergent vessels being present in relationship to the submandibular gland.  The arterial course can significantly impact the surgical flap harvest time.  In addition, the presented classification system can aid in categorizing flap characteristics to standardize outcome measure reporting.