Propeller Flaps for Lower Back Defects

A 33-year-old man was referred to the plastic surgery service for management of a complex lower back wound. His medical history is significant for right sacral Ewing’s sarcoma diagnosed at the age of 17 years. The tumor was initially treated with chemoradiation but recurred locally 2 years later, requiring an extended right hemisacrectomy. Spinopelvic stabilization was performed with pedicle screws and rods and allograft fibula. Right L5 and all sacral nerve roots were resected, resulting in partial right lower limb paralysis, leaving him crutch dependent for ambulation.

He now presents 11 years later with an infection of the L4-L5 fixation site, leading to formation of a sinus tract. He was taken to the operating room by the orthopedic surgery service who performed debridement of nonviable tissue, removal of spinal instrumentation, and placement of antibiotic beads. The wound is now open and radiated (Figures 1 and 2).

The lower back is a particularly challenging area to reconstruct. Due to the paucity of skin laxity, traditionally designed local flap options are limited to small defects. This may be further hindered by prior radiation, infection, and surgery, as was the case in this patient. Locoregional flaps, such as latissimus, trapezius, and paraspinous muscle flaps, are more suited for cervical and thoracic defects as they do not reliably reach the lower back and come with the morbidity associated with muscle harvest. The small diameter and short pedicle length of recipient vessels in the region limits the feasibility of free tissue transfer. When free tissue transfer is necessary, long vein grafts may be necessary to reach well-known recipient vessels (eg, the thoracodorsal artery), which may be at higher risk of compression and kinking. Moreover, postoperative positioning to protect free flaps and their pedicles from mechanical or shear injury is challenging. In this context, propeller flaps variably based on the superior gluteal, lumbar, and posterior intercostal vessels have become more widely used for the lumbosacral defect (Figure 3).

The goal of reconstructing the lower back defect is to achieve reliable and durable wound healing with coverage of critical anatomical or orthopedic structures. This permits early mobilization to minimize postoperative complications and deconditioning; in the patient with cancer, efficient wound healing also ensures timely adjuvant treatment. The minimum requirements to achieve primary healing include radical debridement of all devitalized and grossly contaminated or infected tissues, the recruitment of well-vascularized tissue, the judicious obliteration of dead space, and the tension-free apposition of skin. As much as possible, the reconstruction should aim to restore “like-for-like” tissue in terms of the color, texture, and, importantly, the thickness and pliability of the normal soft tissues to minimize wear and tear from mechanical shear forces. Finally, as is illustrated in this case, with preservation of the patient’s latissimus dorsi muscle, donor site morbidity should always be minimized to avoid adding insult to injury.

First described by Katsoris and Hyakusoku,¹ the propeller flap is an axially designed flap that is eccentrically islanded on a perforator,² allowing for rotation up to 180 degrees into the defect. The eccentric positioning of the perforator adjacent to the defect allows for tension-free closure of the donor site. Conceivably, it was a design innovation arising out of a period of improved understanding of perforator anatomy^2-5 and growing confidence in the technical aspects of perforator-level surgery through “supermicrosurgery” and “freestyle flap surgery.”^6-8 Generally, propeller flaps are indicated for moderate-sized defects with healthy surrounding tissue quality and vasculature. The operation is relatively quick and helps achieve “like-for-like” cutaneous reconstruction. Its main downsides are its limited ability to obliterate dead space, a steep learning curve to correctly select and dissect the appropriate perforator, and an overall complication rate that is higher than that associated with free flaps. In a recent literature review of studies published from 1991 to 2015 including 1242 patients who underwent 1315 propeller flap procedures, the overall complication rate associated with propeller flaps was 23%.⁹ Total flap loss (2.7%), partial flap failure (6.5%), and venous congestion (5%) accounted for 14% of these complications,^9,10 meaning that perforator flaps may have a higher overall success rate than free flaps. Complications were more commonly seen in the lower limb (20.7%), twice as frequently as the trunk and perineum (11.2% each). 

The back generally lends itself to propeller flaps as it is rich in cutaneous perforators. Kedar et al¹¹ have conveniently mapped these perforators into 3 vertical zones – zone 1 (dorsal), zone 2 (dorsolateral), and zone 3 (lateral) (Figure 4). Whereas the source vessels of these perforators vary between and even within their zones, extensive choke anastomoses have been demonstrated between perforasomes, allowing large flaps to be reliably raised on a single perforator. The design of these flaps should be perpendicular or oblique to the axial skeleton to (1) optimize their vascularity and (2) take advantage of the available laxity in the back.

For lumbosacral defects specifically, the contralateral zone 1 or ipsilateral zone 1 and 2 perforators arising from the posterior intercostal, lumbar, or superior gluteal artery systems are all options on which to base a flap. Defect size, donor tissue quality and laxity, as well as perforator caliber determine which perforator is most appropriate in a given patient. In this case, to take advantage of the laxity in the “love-handle” area, a superior gluteal artery perforator flap was initially planned; however, no sizable cutaneous perforator could be identified via an initial exploratory incision incorporated into a preliminary flap design (Figure 5). Subsequently superior to the defect, where there was considerable laxity in the upper flank, a dorsal intercostal artery perforator was randomly identified with doppler ultrasound and interrogated intraoperatively, confirming it to be usable based on its size (~1.5 mm) and pulsatility. The flap was islanded and raised in a subfascial plane, and the perforator dissected through the deep fascia to avoid constriction as it made a gentle 90-degree turn (Figure 6). Robust flap perfusion was confirmed with indocyanine green angiography (Figure 7). However, following flap inset and direct closure of the donor site, the flap was noted to be somewhat congested. Thus, one of the edges of the flap was left open with a negative pressure dressing. After a week, the inset was completed, leading to a well-healed flap that resurfaced the wound (Figure 8).

Affiliations: ¹Department of Plastic and Reconstructive Surgery, Memorial Sloan Kettering Cancer Center, New York, NY; ²Division of Plastic and Reconstructive Surgery, The Mount Sinai Hospital, New York, NY; ³Department of Plastic and Reconstructive Surgery, St. Vincent’s Hospital, Melbourne, Australia

Correspondence: Edwin Morrison, MBBS; morrise2@mskcc.org

Disclosures: None of the authors state any financial disclosures, commercial associations, or other conditions posing a conflict of interest to report.