Introducing the subdermal free flap: Preserving the ultrathin-free skin flap option in morbidly obese patients

The Impact of Increased Body Mass Index on Patient Outcomes and Complications in Microsurgical Lower Extremity Reconstruction

BACKGROUND

Elevated body mass index (BMI) is a known perioperative risk factor for complications such as delayed wound healing and infection. However, there is a gap in understanding how elevated BMI impacts outcomes after posttraumatic lower extremity (LE) microvascular reconstruction.

METHODS

A retrospective review was performed at a level 1 trauma center between 2007 and 2022 of patients who underwent posttraumatic microvascular LE reconstruction. Demographics, flap/wound details, complications, and outcomes were recorded. Patients were stratified into BMI Center for Disease Control categories.

RESULTS

A total of 398 patients were included with an average BMI of 28.2 ± 5.8. Nearly half (45%) of LE defects were located in the distal third of the leg, 27.5% in the middle third, and 34.4% in the proximal third. Most reconstructions utilized muscle-containing flaps (74.4%) compared with fasciocutaneous flaps (16.8%). Surgical approaches included free flaps (47.6%) and local flaps (52.5%). Class III obese patients were significantly more likely to be nonambulatory than nonobese patients (OR: 4.10, 95% CI 1.10-15.2, p = 0.035). At final follow-up, 30.1% of patients with Class III obesity were ambulatory, requiring either wheelchairs (42.3%) or assistance devices (26.9%). There were no significant differences in complication rates based on obesity status (0.704). The average follow-up time for the entire cohort was 5.8 years.

CONCLUSIONS

BMI is critical for patient care and surgical decision-making in LE reconstruction. Further research is warranted to optimize outcomes for higher BMI patients, thereby potentially reducing the burden of postoperative complications and enhancing overall patient recovery.

The SIEA SHRIMP Flap: An Ultrathin Axial Pattern Free Flap Useable in Obese Patients

The reconstruction of distal extremity wounds poses a unique surgical challenge. In free tissue transfer, a thin, pliable skin flap is the ideal. Obese patients have a paucity of thin skin donor sites. Herein we report the discovery of a free SHRIMP flap (Superthin Harvest of a Reliable Islanded Medial Pannus flap) based on the SIEA vessels, harvested from a thick abdominal pannus at the time of cosmetic abdominoplasty. A 61-year-old woman with a chronic wound of the right Achilles tendon was evaluated for reconstruction after failing conservative measures. At the time of consultation, the patient expressed interest in abdominoplasty. Therefore, a skin flap from the abdomen or rectus abdominis muscle flap in the context of an abdominoplasty was offered. Despite obesity affecting the pannus, the superficial inferior epigastric vessels were found to course superficially beneath the dermis at time of abdominoplasty. This allowed straightforward harvest of a superthin flap of skin and minimal subcutaneous fat, which contoured to the ankle with an aesthetically pleasing outcome. The patient was satisfied with the results of her abdominoplasty and coverage of her chronic wound. The SHRIMP flap provides a straightforward, axial pattern, superthin free skin flap based on the superficial inferior epigastric vessels, and represents a useful option in obese patients. The flap can be combined with abdominoplasty for an aesthetic donor site.

Influence of BMI, Age, and Gender on the Thickness of Most Common Thinned Flaps

Background:

Since the description of superficial fascia flap harvesting, a new window of opportunity has been open in obese patients, where a higher subcutaneous thickness of tissue is present. To our knowledge, the impact of body mass index on superficial fascial flaps has not been reported.

Methods:

We recruited 122 patients from April 2019 to January 2020. From these patients, the 3 most common thinned flaps were selected: the superficial circumflex iliac perforator flap; the anterolateral thigh flap at the perforator A, B, and C; and the thoracodorsal flap. Two vertical measures were registered: the distance from the skin to the superficial fascia, and from this point to the deep fascia.

Results:

The average flap measurement presented here was within the range, as previous clinical studies. The superficial fatty layer thickness in the superficial circumflex iliac perforator and anterolateral thigh flap was somewhat similar in thickness between overweight and obese patients, showing a minimal increase with higher body mass index. The anterolateral thigh flap was found thicker among women, and no statistical difference was shown between age groups in any of the flaps.

Conclusions:

A better understanding of the fat layers’ thickness will result in better planning, minimizing secondary debulking procedures, decreasing operative time, and reducing general complications among obese patients. Thus, a better understanding of flap structure and physiology in obese patients will lower complications and give more predictable results.