Microvascular Reconstruction: Principles and Soft Tissue Flap Selection

Hi Team,

We're moving from neck management into microvascular reconstruction this week. Wednesday mornings at 7 AM, donuts and coffee for anyone who can join in person (we MAY also go with a healthy option as well this week! Please grab any of us in the OR if you can't make it to the actual session at 7AM and hope this helps to drive some conversation.

This week's topic is the framework for choosing a flap and the two workhorse soft tissue options, anterolateral thigh (ALT) and radial forearm free flap (RFFF). Next week we'll cover osteocutaneous flaps and the complications that keep us up at night. If you haven't checked the link below that has all of our papers and resources, I'd highly check it out, look in the textbook section, and make sure you look through some of the "Flaps and Reconstructive Surgery" textbook - it has a lot of great technical review of flap physiology and then almost all regional and free flaps have a chapter including relevant anatomy and steps of the procedure.

Choosing a Flap: The Reconstructive Ladder and the Vessel-Depleted Neck

Before you can pick a flap you need a defect-specific goal. The curriculum's reconstructive ladder runs through oral cavity, oropharyngeal, laryngopharyngeal, maxillectomy, and skull base defects, and for each one the question is the same: what does this specific patient need restored, bulk, epithelial lining, sensation, bone, or some combination, and at what cost in donor site morbidity. A hemiglossectomy defect and a total glossectomy defect are not the same reconstructive problem even though both start with "tongue."

The angiosome concept is worth revisiting early in this rotation. Understanding which vascular territories supply which skin paddles is what lets you design a flap that survives, not just one that looks right on the intraoperative photo. Recipient vessel selection is the other half of the equation, and it gets harder the more treatment a patient has had.

The vessel-depleted neck is its own curriculum topic, and it's worth knowing the numbers behind it. A systematic review of 26 studies and 325 patients undergoing microvascular reconstruction in a vessel-depleted neck found a 34.5% postoperative complication rate and 3.7% mortality (Frohwitter J Craniomaxillofac Surg 2018). ALT and radial forearm remained the most commonly harvested flaps even in this population, and the internal mammary vessels were the most frequently used recipient artery, with the cephalic vein doing the most work on the venous side. A short vein graft off the external jugular or, more often, the greater saphenous vein, remains the simplest fix when you need a few extra centimeters, and most reconstructions don't need to escalate beyond it.

The stakes rise fast once a flap starts to fail. A multicenter review of 79 flaps requiring a second salvage attempt, meaning the flap had already been taken back once for compromise and failed again, found the second attempt succeeded only 30% of the time (Slijepcevic JAMA Otolaryngol Head Neck Surg 2022). Arterial or venous thrombectomy at that second look was associated with better odds of salvage; converting the venous anastomosis to a different outflow vein was associated with worse odds. Worth internalizing as you're the one taking a flap back at 2 AM: your first take-back is usually your best shot, so how thoroughly you explore the pedicle and whether you thrombectomize versus re-do the anastomosis matter more than you might assume a second attempt will forgive. When further free tissue isn't realistic, regional pedicled flaps (pectoralis major, latissimus, supraclavicular, submental, trapezius) remain legitimate salvage options for large defects (Chang Laryngoscope Investig Otolaryngol 2022).

A multi-institutional review of nearly 2,900 free flaps found no significant difference in flap failure, complication rate, or length of stay between the first and last academic quarters of the year (De Ravin World J Otorhinolaryngol Head Neck Surg 2025). First-quarter cases did run longer and had a modestly higher dehiscence rate, so a "July effect" isn't entirely absent, but it does not appear to translate into worse patient outcomes with appropriate oversight. Overall flap failure across the cohort was 4.9%, a useful number to keep in your back pocket for boards.

ALT versus Radial Forearm: The Workhorse Debate

Radial forearm gives you thin, pliable, reliable tissue with a long pedicle, tracing back to Soutar's original 1983 description of the flap for intraoral reconstruction (Soutar Br J Plast Surg 1983), at the cost of a forearm donor site that patients notice for the rest of their lives. ALT gives you more tissue and less donor site morbidity for most patients, at the cost of a pedicle that is occasionally frustrating to dissect. A multicenter review of over 1,000 planned ALT flaps found that 2.6% had to be abandoned for absent or inadequate cutaneous perforators, with an overall flap loss rate of 3.2%, and it's worth knowing the salvage options ahead of time: anteromedial thigh, contralateral ALT, radial forearm, or a regional flap depending on what's already been dissected (Thomas Laryngoscope 2020). That perforator variability aside, ALT's long-term track record is strong: an early landmark series of 672 ALT flaps reported total failure in just 1.8% (Wei Plast Reconstr Surg 2002).

Here's the rule of thumb worth internalizing: you can always take tissue away, but you can't easily add it back. A radial forearm flap that shrinks with time, particularly after radiation, can tether and contribute to trismus, and there's no good way to add volume back once that happens (unless you'd like to do another flap at a later date). An overly bulky ALT, by contrast, can be debulked in a short secondary procedure without much added morbidity. Super-thin ALT harvest, taking the flap above the deep fascia to shave down bulk at the time of the original operation, has been directly compared to radial forearm in a 2026 series and found broadly comparable in outcomes (Heo Microsurgery 2026), but the debulking option is why ALT tends to be preferred for slightly larger defects when the radial forearm may seem like the more straightforward choice up front. The medial sural artery perforator (MSAP) flap is worth knowing as a middle ground here: radial forearm averages about 4mm thick, MSAP about 7mm, and ALT about 10mm, so MSAP is a legitimate option when radial forearm feels too thin but a standard ALT feels like overkill (Danielian Otolaryngol Head Neck Surg 2023).

Two other soft tissue options deserve a mention even though they come up less often. The lateral arm flap gives excellent color match to facial skin, well-compartmentalized fat that resists ptosis, and a donor nerve available for grafting, which makes it a strong option for parotid and periauricular defects specifically (Kang Oral Oncol 2018). And for large composite defects, particularly a large scalp defect or a laryngopharyngectomy defect with a significant skin component, the latissimus dorsi myocutaneous flap remains a robust option in high-risk or previously radiated patients where other flaps may be inadequate (Kinkhabwala Head Neck 2024).

Flap Monitoring - Doppler and Clinical Exam Findings

Clinical exam remains the backbone of postoperative flap monitoring, and it always will, but implantable Doppler is no longer a niche adjunct. A 2023 systematic review and meta-analysis found implantable arterial Doppler probes meaningfully improve detection of vascular compromise compared to clinical monitoring alone (Wu Head Neck 2023), and a single-center cohort of 181 patients reported a 100% positive predictive value for detecting vascular anomalies with the Cook-Swartz probe (Cervini Eur Ann Otorhinolaryngol Head Neck Dis 2025). That same series is a reminder that early detection doesn't guarantee salvage, particularly for venous thrombosis, which the arterial probe alone can miss (maybe why I like to use venous dopplers when able!). Ultimately, understanding flap physiology, why an artery may go down from hypotension, vasospasm, or thrombosis, or why a vein may go down from compression, poor geometry, or clotting, is what turns a clinical exam finding into an urgent trip back to the OR instead of a wait-and-see.

Thanks for taking the time to read this, and looking forward to discussing further on Wednesday!

Have a great week!

Rob