05/06/2026
Dorsoulnar flap( Brunelli flap)
Before you consult plastics or jump to a complex free flap for a thumb defect, you need to understand the anatomy and utility of the dorsoulnar flap.
This diagram perfectly captures the essence of this workhorse flap. Let's break down exactly when and how you should be using this in your practice.
Indications:
Volar Thumb Defects: Ideal for medium-sized soft tissue defects on the volar aspect or tip of the thumb.
Exposed Vital Structures: When bone, joint, or tendon is exposed and a simple skin graft won’t survive.
Failed Local Advancement: When a Moberg flap won't give you enough reach for a distal injury.
The Procedure:
1 The Design: The flap is designed over the dorsoulnar aspect of the thumb, centered over the MCP joint.
2 The Harvest: You elevate the skin paddle and pedicle, working proximal to distal. Look at the text at the bottom bipolar electrocoagulation is your best friend here to maintain meticulous hemostasis.
3 The Pivot Point: This is the most critical part of image. See the dotted line labeled "Distal limit of dissection" set 1 cm proximal to the crease? Respect that line. Going further risks transecting your perforators.
4 The Rotation: The text notes you can get an 8 cm pedicle. This allows for excellent rotation to the volar thumb, but ensure there is zero tension or kinking of the pedicle.
The Pros:
"Like-with-Like" Tissue: Replaces thumb skin with local, durable skin.
Single-Stage: Gets the patient out of the OR and healing without needing a second division surgery (unlike a cross-finger flap).
Reliable Blood Supply: Based on a robust, constant axial vessel.
The Cons:
Donor Site Morbidity: You will almost always need a full-thickness skin graft to close the donor site on the dorsum of the thumb.
Venous Congestion: The primary reason these fail in junior hands is tight tunneling. (Pro tip: Just open the skin bridge!).
Bulkiness: It can be slightly bulky at the recipient site, occasionally requiring debulking later down the road.
Save image to your phones. Review it before your next thumb trauma case!