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Case Reports: Transsciatic Foramen Pedicle VRAM Coverage of Gluteal Defects

Tran, Nho, V; Sim, Franklin, H; Lewallen, David, G; Carmichael, Stephen, W

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Clinical Orthopaedics and Related Research: November 2006 - Volume 452 - Issue - p 270-273
doi: 10.1097/01.blo.0000229303.59771.6d


A gluteal wound can be a challenge to close in ambulatory patients requiring full gluteal muscle function for ambulation. Preoperative irradiation makes the use of local tissue (eg, V-Y gluteus maximus flaps) less desirable by possibly compromising function. This situation causes problems for wound closure.

When the posterior defect is off the midline, regional pedicle flap options from the thighs (eg, gracilis myocutaneous flap,4,8 tensor fascia lata,9,15 and posterior thigh flap13) may be possible, but are limited by size, reach, and morbidity. Larger defects often require a free tissue transfer with an arteriovenous conduit from the femoral vessels.1,5-7 We report our experience with a pedicle vertical rectus abdominis myocutaneous flap (VRAM), a simple regional reconstructive option for gluteal wounds through a new tunnel via the transsciatic foramen route. The rectus abdominis muscle with acceptable donor-site morbidity has a reliable vascular anatomy. As a regional option, the transpelvic VRAM is the workhorse for a posterior mid- line wound after abdominal perineal resection where absence of the rectum provides a natural tunnel for the flap transfer.14 Unlike a midline abdominoperineal resection (APR) defect, a posterolateral defect has no obvious passage for the pedicle rectus flap that does not reach the posterior defect by the subcutaneous route because of a short pedicle. To allow the pedicle VRAM flap to reach a posterior paramedian wound, the bulky flap can be delivered through the transsciatic foramen route.

The cases of two patients in whom we performed transsciatic foramen VRAM for coverage of gluteal defects are reported. We performed the procedure in one patient with malignancy and in another patient for treatment of an infected hip.

Patient 1

A 63-year-old woman with a history of colon cancer and anemia presented with a rapidly growing painful mass in the right gluteus maximus muscle over 3 months. Magnetic resonance imaging (MRI) revealed an 11 × 10 × 11-cm soft tissue mass bulging through the greater sciatic notch and abutting the rectum (Fig 1). A computed tomography (CT)-guided biopsy showed Grade 4 pleomorphic sarcoma. The workup showed no evidence of distant disease. The patient was treated with preoperative external beam radiation (5040 cGy) before the resection, intraoperative radiation (1000 cGy), and immediate reconstruction with a transsciatic foramen VRAM flap. The 18 × 25-cm irradiated wound had an exposed sciatic nerve and rectum. The right inferior-based rectus muscle included a 20 × 25-cm healthy nonradiated skin island. We passed the flap through the retroperitoneum and delivered it to the right gluteal defect by a direct route through the greater and lesser sciatic foramina after dividing the sacrospinous and sacrotuberous ligaments (Fig 2). There were no wound complications. Postoperative pain with sitting was treated with gabapentin (Pfizer, Inc, La Jolla, CA) for 6 months. She was able to walk without an assistive device after 6 months. The patient continues to walk independently and is disease-free 6 years later.

Fig 1A
Fig 1A:
D. (A) Patient 1 had a Grade 4 pleomorphic sarcoma after 5040 cGy external beam irradiation. (B) A preoperative MRI shows the tumor abutting the rectum. (C) A 6-month postoperative photograph shows complete healing of the right pedicle transsciatic foramen VRAM flap. (D) A postoperative photograph of the abdominal donor site shows scars from the 20 × 25-cm skin flap harvest.
Fig 2A
Fig 2A:
D. (A) An intraoperative photograph shows the patient placed on her left side in a lateral position. The posterior 18 × 25-cm irradiated defect shows the sciatic nerve in the center of the field and rectum- anus in the right corner of the picture. (B) An anterior view of the abdomen shows the right rectus myocutaneous flap before transfer to the gluteal area. The patient is in the left lateral position and the pubis is adjacent to the hemostat. (C) The transsciatic tunnel was made after dividing the sacrotuberous ligament and blunt dilation with the finger was used to enlarge the path in preparation for passage of the bulky flap. (D) A diagram shows the divided sacrospinous and sacrotuberous ligaments in relation to the sciatic nerve and VRAM flap in the tunnel.

Patient 2

A 41-year-old woman with insulin-dependent diabetes had a right total hip arthroplasty (THA) 2 years before a progressive, expansive fluid accumulation developed causing her pain and loss of function. She was diagnosed with Malassezia furfur infection. The patient required surgical débridement and component removal because of chronic infection and massive thigh muscle necrosis. The patient required multiple débridements, excision of the sinus tract, and neurolysis of the sciatic nerve. At the last débridement, the large, infected cavity with exposed sciatic nerve was filled with a vascularized pedicle VRAM flap through the transsciatic notch tunnel. The patient healed and the infection resolved to allow a second THA 1 year later.


The rectus abdominis myocutaneous flap vascular anatomy was studied by Moon and Taylor.11 Its blood supply is the dominant deep inferior epigastric artery, and to a lesser degree, the deep superior epigastric and inter- costal arteries. The VRAM based on the deep inferior epigastric artery is the workhorse for sacral, midline defects in abdominoperineal resections as it can be transposed easily via a transpelvic route because of the absence of the rectum or sacrum.14 For paramedian wounds such as gluteal and ischial areas, traditional flaps from the thigh2-4,8-10,12,15 and gluteus muscle10 have been used for closure. Traditional local and regional options are inadequate for large defects, such as the 20 × 25-cm defect in Patient 1. A free flap frequently is necessary to obtain wound healing.6 Instead of using a free flap, we used an inferiorly based VRAM flap through a new tunnel, transsciatic foramen as the transpelvic route is unavailable with the rectum still in place. Additionally, any subcutaneous path around the hip will not allow the flap to reach the gluteal defect. After exploration to confirm an intact deep inferior epigastric vascular pedicle in the rectus muscle, the VRAM flap could be elevated. Absence of the vascular pedicle and frozen pelvis from prior surgeries and irradiation contraindicate this flap elevation and transposition. We made an ipsilateral transsciatic foramen tunnel to directly connect the anterior abdominal wall to the posterior gluteal wound for flap transposition. This tunnel was made by dividing the sacrospinous ligament and using blunt finger dissection to incorporate the lesser sciatic foramen into the greater sciatic foramen to allow passage of the bulky flap. Without division of the sacrospinous ligament, the greater sciatic foramen alone would be too narrow for flap transfer. If necessary, the sacrotuberous ligament can be divided to further enlarge the potential tunnel. The ligaments can be palpated medial to the course of the internal iliac artery pulsation (Fig 2D). Through this enlarged tunnel medial to the sciatic nerve, the flap was transferred to reach the gluteal area by a direct route (Fig 2C). In addition to creating a direct tunnel to improve the flap reach and therefore avoid pedicle tension, the inferiorly based VRAM was designed with the skin over the costal margin. With the skin island superior to the umbilicus, the intact infraumbilical anterior rectus sheath was sutured to the posterior rectus sheath at the arcuate line to allow abdominal fascia closure without use of a synthetic mesh. Our first patient with an irradiated defect from resection of malignancy had reconstruction using this technique and healed without complication. She ambulates without an assistive device. Patient 2, who had thigh compartment syndrome and extensive myonecrosis, had few viable options from the extremity muscle to cover the exposed sciatic nerve and infected THA cavity. To reach the sciatic, acetabular, and proximal femur areas, the sacrospinous ligament division enlarged the greater sciatic foramen to allow the myocutaneous flap to reach the infected cavity without tension. This patient's chronic pain improved, the infection resolved, and she had a second THA 1 year after the flap surgery.

Both flaps survived without complications. None of the patients had sciatic nerve compression symptoms, as the nerve was in contact only with the relatively small rectus muscle in the large tunnel, whereas the bulky subcostal skin paddle covered the skin defect. Additionally, no ventral or internal hernia occurred at the donor site, and there has been no functional morbidity from the sacrospinous ligament division. The transsciatic foramen approach allowed reliable coverage of defects with the pedicle VRAM.


We thank Donna M. Fisher, BA, BFA, for scientific editing.


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