A Descriptive, Retrospective Study of Using an Oblique Downward-design Gluteus Maximus Myocutaneous Flap for Reconstruction of Ischial Pressure Ulcers

Despite advances in reconstruction techniques, ischial pressure ulcers continue to present a challenge for the plastic surgeon. The purpose of this retrospective study was to evaluate outcomes of using an oblique downward gluteus maximus myocutaneous (GMM) flap for coverage of grade IV ischial ulcers.Data regarding defect size, flap size, operation time, duration of wound healing, and surgical outcome were abstracted from the medical records of patients whose ischial pressure ulcers had been reconstructed using GMM island flaps between January 2010 and December 2015. The 22 patients comprised 15 men and 7 women with a mean age of 52 (range 16–81) years. Twenty (20) had paraplegia, 6 had a recurrent ischial ulcer, 2 were bedridden following a cerebrovascular accident, 1 had a myelomeningocele status post operation, and 19 were spinal cord injury patients. Follow-up time ranged from 6 to 40 months. Pressure ulcer size ranged from 3 cm x 2 cm to 10 cm x 5 cm (average 22.3 cm²). The average flap size was 158 cm² (15.9 cm x 9.7 cm); the largest was 286 cm² (22 cm x 13 cm). The operating time ranged from 52 minutes to 110 minutes (average, 80 minutes). In 2 cases, wound dehiscence occurred but completely healed after resuturing. One (1) ischial pressure ulcer recurred 6 months following surgery and was successfully covered with a pedicled anterolateral thigh flap. No recurrences or problems were observed in the remaining 20 patients. Time to complete wound healing ranged from 14 to 24 days (average 17.8 days). Treatment of ischial pressure ulcers with GMM flaps allowed for an easy, simple procedure that provided the adequate thickness of soft tissue needed to cover the bony prominence, fill dead space, and cover the lesion. This technique was a reliable and safe reconstructive modality for the management of ischial pressure ulcers, even in recurrent cases.

Ischial pressure ulcers are the most common type of pressure injury to occur in the wheelchair-bound patient; the risk of recurrence is constant despite successful surgical treatment.^1,2 Recurrence rates vary widely from 7% to 48%,² indicating the difficulty in estimating a single factor that influences recurrence, although recurrence typically is related to persistent dead space in the wound cavity, shear forces on the tissue planes, and accumulation of serous fluids.³ Many different types of flaps are available for surgical coverage of ischial pressure ulcers; these include the anterolateral thigh perforator flap,¹ profunda femoris artery perforator flap,² freestyle perforator-based flap,⁴ medial circumflex femoral artery flap,⁵ gracilis muscle flap,⁶ medial gastrocnemius free flap,⁷ inferior gluteal artery perforator flap,⁸ and lateral thigh V-Y flap,⁹ but evidence to aid in the selection of optimal treatment is limited. Due to the high recurrence rate of ischial pressure ulcers,¹⁰ reconstruction design should allow coverage of the ulcer but not limit the use of other flaps in the future. 

The oblique downward-design gluteus maximus myocutaneous (GMM) flap is a composite flap that provides adequate thickness of soft tissue to pad pressure points. With careful design, the superior gluteal artery perforator can be preserved for future use. 

The purpose of this retrospective study was to evaluate outcomes of patients whose ischial ulcers were treated using the oblique downward-design GMM flap. 

The records of all patients admitted between January 2010 and December 2015 to the Tri-Service General Hospital, Taipei, Taiwan, with a diagnosis of grade IV ischial pressure ulcers who underwent GMM flap surgery were retrieved. Defect size, flap size, operation time, duration of wound healing, and surgical outcome were abstracted from the medical records. Patients were candidates for this surgery if they had a grade IV ischial pressure ulcer. Patients with severe cardiac or pulmonary comorbidities and/or who would not be able to tolerate anesthesia were excluded. 

Wound tissue was cultured to assess for wound infection and osteomyelitis; broad-spectrum antibiotics were prescribed preoperatively for each patient and were changed to specific antibiotics if a specific organism was isolated from the wound culture. Presurgical treatment included extensive debridement of necrotic tissue and open drainage. Wet gauze dressing, changed twice a day, was applied for local wound care. After adequate debridement and local wound management that included antibiotic agent treatment, reconstructive procedures were performed when healthy granulation tissue was present at the wound base. 

Surgical procedure. All reconstructions using the oblique downward-design GMM flaps were performed by 1 surgical team led by the senior attending physician. After radical debridement and osteotomy of the bony prominence, an elliptical flap was designed from the side closest to the ischial pressure ulcer (see Figure 1). The composite musculocutaneous flap was harvested and shifted downward medially to cover the defect, and the wound was closed in the V-Y manner (see Figure 2). Care was shown to ensure the length of the designed flap was more than twice the size of the defect. 

After the operation, a low-residual diet was provided for 2 weeks to reduce defecation and help prevent fecal contamination to the wound; meticulous perineal hygiene was maintained.¹¹ Patients were kept entirely nonweight-bearing on the ischial area for 4 weeks. Pressure was offloaded using an air-fluidizing bed; wheelchair use was avoided. The patient was repositioned to prone position and sidelying every 2 hours until the flap healed (see Figure 3).

Of the 22 patients included in this study (ie, patients who underwent this procedure during the time stipulated), 15 were men and 7 were women, with a mean age of 52 (range 16–81) years. Follow-up extended an average of 20 months and included photography and telephone interviews. The majority of participants (20) had paraplegia; 6 had recurrent ischial ulcers, 2 were bedridden long-term following a cerebral vascular accident, 19 were spinal cord injury patients, and 1 was a patient with a myelomeningocele status post operation (see Table 1). 

Average time from initial debridement to reconstruction was 2 weeks (range 1 week to 4 weeks). 

Pressure ulcer size ranged from 3 cm x 2 cm to 10 cm x 5 cm (average 22.3 cm²), although the size of the wound base was typically several times larger than that of the skin defect. The average flap size was 158 cm² (15.9 cm x 9.7 cm); the largest was 286 cm² (22 cm x 13 cm). Operating time ranged from 52 minutes to 110 minutes (average 80 minutes). Duration of wound healing ranged from 14 days to 24 days (average 17.8 days). Wound dehiscence occurred in 2 patients but their wounds were completely healed after resuturing. No surgery-related mortality occurred. The longest follow-up was 40 months. Good outcomes (ie, wound healing without surgical complication such as flap necrosis or wound dehiscence) were achieved except for 1 recurrence of an ischial pressure ulcer (patient 2) 6 months after operation; this was treated successfully with a pedicled anterolateral thigh flap. The other 21 patients had no recurrence noted for a follow-up period of 6 to 40 months (average 20.3 months).

Reconstructive surgery for pressure ulcer defects presents a difficult challenge; an outcomes analysis¹² showed patients with pressure ulcers often are bedridden, paraplegic, or quadriplegic. Ischial pressure ulcers are the most difficult pressure ulcers to treat because the ischial area is mobile and vulnerable to pressure when a person is in the sitting position.¹³ In addition, position changes involving flexion and extension of the lower extremities influence the tension on and size of the pressure ulcer. According to the report by Conway and Griffith¹⁴ on the basic tenets of surgical treatment of pressure ulcers, treatment should involve excision of the ulcer, surrounding scar, underlying bursa, and soft tissue calcifications, if any, as well as radical removal of underlying bone and any heterotopic ossification. Padding bone stumps and filling dead space also were suggested. Inadequate debridement can lead to treatment failure; tissue removal usually reveals dead spaces under the surface of the skin, necessitating further flap reconstruction.

Although different types of flaps (ie, muscle, myocutaneous, and fasciocutaneous) are available for the surgical closure of ischial pressure ulcers, the optimal treatment remains controversial.^1,2,4-9 A systematic review³ revealed recurrence and complication rates of 8.9% and 18.6%, but differences with regard to recurrence or complication rates among musculocutaneous, fasciocutaneous, or perforator-based flaps for pressure ulcer coverage were not significant. 

Many factors may affect the occurrence of pressure ulcers, including immobility, incontinence, poor nutritional status, and changes in consciousness.¹⁵ Retrospective chart reviews^16,17 have shown the type of surgical flap should be selected according to its ability to provide the adequate bulk for soft tissue coverage, vascularization, and sensory recovery fundamental to the reconstruction of pressure ulcer, as well as the importance of educating the caregiver on pressure ulcer management, especially pressure redistribution. 

Fasciocutaneous flaps based on the anterolateral thigh perforator flap, gluteal perforator flap, gracilis perforator flap, or profunda femoris perforator flap and their various modifications also have been used to treat ischial pressure ulcers.^2,18 Flaps that provide inherent skin coverage and have good blood supply do not necessitate sacrifice of major vessels or nerves of the donor site; insufficient bulk and structural instability are disadvantages when reconstructing a wound with significant depth. Moreover, with the advent of reconstructive microsurgery, the use of free flaps has become the first choice of treatment to cover and reconstruct such defects.¹⁹ However, in the authors’ experience, the use of free flaps presents certain disadvantages, including donor-site morbidity, increased operation time, use of a major leg vessel, and the necessity of microsurgical expertise. 

Myocutaneous flaps have sufficient bulk and robust vascularization and have been reported in chart review studies to be the method of choice for the surgical repair of pressure ulcers.^20,21 The muscle part of flaps can be helpful in obliterating dead space and supplying reliable vasculature to cushion the tissue over a pressure-bearing area, and the skin paddle is durable in terms of gliding and tolerating the shearing force. This modified GMM flap also can retain the superior gluteal artery perforator flap should there be recurrence. However, myocutaneous flaps sacrifice muscular function that may destabilize walking and, as such, are not an ideal option in ambulatory patients.²⁰ 

This retrospective study noted good outcomes in 21 cases (95.5%) during the average follow-up period of 20.3 months with 1 recurrence that was treated with a pedicled anterolateral thigh flap. A mild complication (wound dehiscence) occurred in 2 cases (9.1%), but the ulcers completely healed after resuturing. The average operating time was 80 minutes. In the authors’ experience, this operation time was shorter  than other reconstructive methods such as traditional V-Y hamstring advancement flaps, profunda femoris arery perforator flaps, or pedicle anterolateral thigh flaps.  

The limitation of this study is inherent in its retrospective design and the lack of a control group. A larger prospective trial should be performed to further examine the outcomes of this procedure.  

A retrospective examination of patient records showed treatment of ischial pressure ulcers with oblique downward design GMM flaps provided an easy, simple procedure and thick soft-tissue sufficient for covering the bony prominence and filling dead space. This technique can be performed more quickly than traditional surgery involving V-Y hamstring advancement flaps, profunda femoris artery perforator flaps, or pedicle anterolateral thigh flaps and is a reliable, safe reconstructive modality for the management of ischial pressure ulcers, even in recurrent cases. Additional studies are needed to further evaluate the long-term outcomes of this method, including larger patient populations, to compare the different outcomes and complications of the different methods of flap coverage.

Dr. Chou is a resident, Division of Plastic Surgery, Department of Surgery, Tri-Service General Hospital, National Defense Medical Center; and a resident, Department of Surgery, Taoyuan Armed Forces General Hospital, Taipei, Taiwan. Dr. Sun is a fellow, Department of Family and Community Health, Tri-Service General Hospital. Dr. Shih and Dr. Tzeng are physicians, Division of Plastic Surgery, Department of Surgery, Tri-Service General Hospital, National Defense Medical Center. Dr. Chang is a physician, Division of Plastic Surgery, Department of Surgery, Tri-Service General Hospital, National Defense Medical Center; and a physician, Division of Plastic Surgery, Shuang-Ho Hospital, Taipei Medical University, Taipei, Taiwan. Dr. Dai is chief physician and Dr. Lin is a physician, Division of Plastic Surgery, Department of Surgery, Tri-Service General Hospital, National Defense Medical Center.

Please address correspondence to: Chin-Ta Lin, MD, Division of Plastic Surgery, Department of Surgery, Tri-Service General Hospital, National Defense Medical Center, No. 325, Section 2, Cheng-Gung Road, Taipei, Taiwan 11490; email: aarondakimo@yahoo.com.tw