Intraoperative indocyanine green fluorescent angiography‐assisted modified superior gluteal artery perforator flap for reconstruction of sacral pressure sores

ABSTRACT

Pressure sores are often observed in patients who are bedridden. They can be a severe problem not only for patients and their caregivers but also for plastic surgeons. Here, we describe a new method of superior gluteal artery perforator flap harvesting and anchoring with the assistance of intraoperative indocyanine green fluorescent angiography. In this report, we describe the procedure and outcomes for 19 patients with grades III and IV sacral pressure sores who underwent the operation between September 2015 and November 2016. All flaps survived, and two experienced wound‐edge partial dehiscence. With the assistance of this imaging device, we were able to acquire a reliable superior gluteal artery perforator flap and perform modified operations with it that are safe, easy to learn and associated with fewer complications than are traditional.

Introduction

Pressure sores are often observed in patients who are bedridden, and they can be a severe problem. According to previous studies, sacral pressure sores occur more commonly than do pressure sores in other sites, such as the ischium and trochanteric region 1. If the wound is not managed well, ischaemic and necrotic tissue may lead to deep tissue infection and complications such as sepsis and chronic infection, which can threaten the patient's life 2. Once deep tissue infection is noted, in‐hospital care, along with surgical interventions, is beneficial for the patients. Several different kinds of flaps have been introduced over the years for reconstructing sacral defects, such as local flaps, V‐Y advancement fasciocutaneous flaps, gluteus maximum muscle‐based flaps, inferior gluteal artery perforator (IGAP) flaps and superior gluteal artery perforator (SGAP) flaps 3, 4, 5.

In this report, we describe a new design and harvesting method for SGAP flaps that uses intraoperative indocyanine green fluorescent angiography (ICGFA). With the assistant of this device, we are able to acquire a reliable modified SGAP flap with only one or two major perforators detected to cover patients' sacral defects.

Materials and methods

We retrospectively reviewed data from a total of 19 patients with sacral pressure sores who underwent modified SGAP flap reconstruction surgery with intraoperative ICGFA between September 2015 and November 2016 at the Tri‐Service General Hospital, Taipei, Taiwan. All of the sacral ulcers were classified as Grades III–IV according to Shea's classification 6. The patients were prepared while they were in the prone position under general anaesthesia in a warm operating room. After adequate debridement of the lesion, a hypothetical line was drawn between the posterior superior iliac spine (PSIS) and the lateral border of the great trochanter on the side of the buttock from which the SGAP flap was planned to be harvested. Point A was marked at the medial one‐third of this line as an anatomical landmark for the superior gluteal artery. Then, a 0·1‐mg/kg dose of indocyanine green (ICG) was injected intravenously through central or peripheral routes. At the same time, real‐time laser fluorescent angiography was obtained using the SPY^® intraoperative perfusion assessment system (Novadaq Technologies Inc., Richmond, British Columbia, Canada), and the points at which the ICG uptake was highest were observed and marked as points S (Figure 1). A spindle‐shaped flap was then designed with the axis parallel to the hypothetical line with the size of the sacral defect. We put point S in the middle of the flap as a pivot point and made a 2–3‐cm diameter circle around point S. Then, we elevated the designed flap from the underlying gluteus maximus muscle, except for the tissue within this 2–3‐cm diameter circle, and used this as the new pedicle of our modified SGAP flap. For the entire procedure, we did not need to visualise the perforator (Figure 2). All of the modified SGAP flaps were sutured in a rotation manner, and the donor sites were closed primarily (Figure 3). The patient's age, gender, reason for being bedridden, number of major perforators, quadrant of the perforator, rotation angle and outcome were recorded.

Figure 1.

Patient 9. (A) The anatomic landmark is marked as point A. (B) Intraoperative indocyanine green fluorescent angiography. (C) The major perforators are marked as point S. (D) The perforator detected using Doppler is marked as point D, is far way from point S and does not show a high signal under indocyanine green fluorescent angiography.

Figure 2.

Patient 9. (A–C) A spindle‐shaped superior gluteal artery perforator flap is designed based on the lower point S and rotated clockwise to cover the sacral defect. (D) Immediate image post‐operation under indocyanine green fluorescent angiography showed good vascularity and perfusion of the superior gluteal artery perforator flap.

Figure 3.

Schematic drawing of the stages of operation. (A) The hypothetical line between the posterior superior iliac spine and greater trochanter is drawn (B) Point S is located with intraoperative indocyanine green fluorescent angiography. The wound is debrided, and the superior gluteal artery perforator flap is designed. (C) The modified superior gluteal artery perforator flap is elevated and rotated to cover the sacral defect, and the donor site is closed primarily.

Results

Nineteen patients with different reasons for being bedridden were included in our analysis. The mean age of the patients was 77·9 years, and the flap sizes ranged from 72 to 150 cm². A total of 7 flaps were detected with two major superior gluteal artery (SGA) perforators, whereas 12 flaps had only one major perforator. The most perforators were found in quadrants I and IV (Figure 4). The rotation angles ranged from 60° to 120°. All flaps survived to the 6‐month postoperative follow up. Only two patients developed partial wound‐edge dehiscence as a minor complication (Table 1).

Figure 4.

Distribution of the major perforators detected with indocyanine green fluorescent angiography in this report. Each side of the buttocks is separated into four quadrants by the hypothetical line drawn between the posterior superior iliac spine and greater trochanter, and a perpendicular line is drawn at the medial one‐third.

Table 1.

Characteristics of patients undergoing superior gluteal artery perforator flap reconstruction of sacral pressure sores

Patient no.	Gender/age (years)	Cause of bedridden status	Flap size (cm2)	Major perforator detected	Quadrant of perforator	Rotation angle (°)	Outcome
1	F/74	Dementia	90	1	3	70	Good
2	F/73	Stroke	108	1	1	110	Good
3	M/72	Spinal cord injury	96	1	4	60	Good
4	M/75	Stroke	90	1	2	80	Good
5	M/91	Fracture of femoral intertrochanter	120	1	4	80	Good
6	M/76	Stroke	105	2	1,2	100	Good
7	F/84	Intracerebral haemorrhage	80	1	4	85	Good
8	F/77	Stroke	117	2	1,2	90	Good
9	M/74	Intracerebral haemorrhage	72	2	3,4	75	Good
10	M/83	Parkinson's disease	125	1	2	75	Good
11	M/80	Fracture of femoral intertrochanter	136	1	4	120	Good
12	M/92	Stroke	124	2	3,4	110	Good
13	F/84	Stroke	150	2	1,2	80	Good
14	M/50	Intracerebral haemorrhage	88	1	1	95	Good
16	F/77	HIVD	104	1	4	85	Wound‐edge dehiscence
16	F/72	Herniated Intervertebral Disc	117	2	1,2	75	Good
17	M/84	Dementia	120	2	3,4	100	Wound‐edge dehiscence
18	M/78	Dementia	120	1	1	115	Good
19	F/85	Dementia	135	1	1	70	Good

HIVD, herniated intervertebral disc.

Case report

An 80‐year‐old man acquired a closed fracture of the inter‐trochanteric region of the left femur from a fall that occurred 1 month before admission. Because of severe pain in changing positions, he became bedridden, and an extensive grade IV pressure sore was noted on his sacral region. After undergoing debridement twice and wound bed preparation with negative pressure wound therapy (V.A.C.^® Therapy, KCI, an ACELITY Company, San Antonio, TX), a 14 × 9 cm² SGAP flap based on one major perforator detected under ICGFA was employed for reconstruction of the sacral defect. We elevated the flap without meticulously dissecting the perforator but left a ‘new’ pedicle about 3 cm in diameter. Then, we rotated the flap 120° counter‐clockwise; the flap was sutured, and the donor site was closed primarily with suction drainage. At the 8‐month follow up, the flap had survived well without loss or recurrence of pressure sores (Figure 5).

Figure 5.

Patient 11. (A–E) Steps of the entire procedure. (F) 9‐month follow up.

Discussion

Pressure sores in bedridden patients remain an ongoing problem for plastic surgeons. They are believed to affect more than 2·5 million patients in the USA annually, and they are also a costly and labour‐intensive challenge to the health care system 7. For decades, surgical debridement with subsequent reconstruction was the best treatment for these patients, and different kinds of surgical methods were designed for this purpose. Since Koshima et al. first described a gluteal artery perforator‐based flap for the reconstruction of sacral pressure sores, many methods based on superior gluteal artery, inferior gluteal artery and parasacral artery perforators have been utilised widely in many aspects of plastic surgery due to their advantages 3, 5, 8, 9. Among these, the SGAP flap has been used the most because it provides many advantages related to safety and reliability, less blood loss, preservation of muscles, less donor‐site morbidity and suitability for even extensive defects 5, 10, 11.

While designing SGAP flaps, the key point is to locate the significant nourishment perforators. According to previous anatomical studies, a mean of 5±2 perforators arising from the superior gluteal artery could be found in this area, with variable diameters ranging from 0·6±0·1 mm and providing a 69±56 cm² territory of supplement 12. Presently, the most used device for locating perforators of SGAP flaps is Doppler ultrasonography. After an anatomic landmark is drawn in the medial one‐third of the line between the PSIS and lateral border of the greater trochanter, the device is used around the point to seek perforators. However, this method can sometimes waste time and be unreliable because the major perforator of the superior gluteal artery may be too far away from the anatomical landmark, resulting in the incorrect selection of the minor ones. If the SGAP flap is designed and fashioned with the minor perforators, there may be complications such as venous congestion, partial necrosis and even total failure 8, 13.

Indocyanine green laser angiography has been proven to be an effective and reliable method to use in the preoperative, intraoperative and postoperative evaluation of tissue perfusion 14. It has been used widely in ophthalmology surgery, urosurgery, tumour surgery, neurosurgery and reconstruction surgery, among others 14, 15, 16, 17. With the assistance of this device, we are able to locate the major perforators of the superior gluteal artery precisely and design a flap with adequate vascularity and perfusion. Using the traditional technique, meticulous dissection of the superior gluteal artery perforator is mandatory. However, that technique requires experienced surgeons and may result in complications if the perforator is injured unexpectedly 10, 11. In our technique, we could take advantage of the accuracy of ICG angiography to harvest and anchor the flap in a new way. The major perforator can be preserved in the ‘new’ pedicle, and the surrounding tissue can be protected; the perforator does not need to be truly visualised or dissected from the gluteal muscle. Then, the flap is rotated to cover the sacral defect, either clockwise or counter‐clockwise, depending on the tension. Twisting of the pedicle over 180° is not recommended because it may jeopardise flaps with one perforator and also decrease the viability of flaps with two perforators 18. The donor sites of the SGAP flap can be closed primarily, even in patients with extensive wounds, due to the spindle shape of the flap design and even with the laxity of the buttocks skin in elderly, bedridden patients.

In conclusion, to our knowledge, this is the first report of the intraoperative use of ICGFA for determining the perforators of SGAP flaps. With the assistance of this device, we illustrate a new method of obtaining a modified SGAP flap for reconstruction of sacral pressure sores, which is safe, easy to learn and associated with fewer complications than the traditional technique.