Overview
Definition:
Perineal wound closure after abdominoperineal resection (APR) involves managing the large defect created in the perineum following the removal of the rectum and anus
the use of a Vertical Rectus Abdominis Myocutaneous (VRAM) flap is a reconstructive technique to fill this defect and promote healing, particularly in cases with significant tissue loss or contamination.
Epidemiology:
APR is indicated for conditions like rectal cancer, inflammatory bowel disease, and intractable perianal sepsis
perineal wound complications occur in a significant percentage of these patients, ranging from 10-50% depending on risk factors, making reconstructive techniques crucial.
Clinical Significance:
Effective perineal wound closure after APR is critical to prevent infection, promote primary healing, reduce morbidity, and improve patient quality of life
VRAM flaps offer a robust solution for complex defects, reducing the incidence of rectourethral fistulas, chronic draining sinuses, and hernias.
Indications For Vram Flap
Defect Size:
Large perineal defects that cannot be closed primarily or with local flaps
deep or wide resections.
Tissue Loss:
Significant tissue loss due to tumor extirpation, radiation changes, or infection leading to tissue necrosis.
Contamination:
High-risk contamination of the perineal wound from intra-abdominal or perianal sources.
Previous Failures:
Failure of previous attempts at perineal wound closure or reconstruction.
Patient Factors:
Patients with poor nutritional status, active smoking, or other comorbidities that may impair wound healing.
Preoperative Preparation
Patient Assessment:
Thorough assessment of nutritional status, comorbidities, and previous surgical history
smoking cessation counseling is essential.
Imaging:
CT scan of the abdomen and pelvis to delineate the extent of the tumor, assess for metastasis, and evaluate the viability of the rectus abdominis muscle and flap.
Bowel Preparation:
Aggressive mechanical and antibiotic bowel preparation to reduce bacterial load in the gut and perineal area.
Anesthesia Considerations:
Careful anesthetic planning to manage prolonged surgery, potential blood loss, and postoperative pain
epidural anesthesia can be beneficial.
Donor Site Preparation:
Marking the flap design on the abdomen, ensuring adequate skin island and vascular pedicle (deep inferior epigastric perforators) based on imaging and intraoperative assessment.
Vram Flap Harvest And Transfer
Flap Design:
The flap is designed based on the size and shape of the perineal defect, typically including a rectangular portion of skin, subcutaneous tissue, and the rectus abdominis muscle with its vascular supply from the deep inferior epigastric perforators.
Harvesting Technique:
Careful dissection of the flap from superficial to deep, identifying and preserving the main vascular pedicle
Perforators are dissected through the muscle to ensure adequate blood supply.
Perineal Defect Preparation:
The perineal defect is debrided of any necrotic tissue, and hemostasis is achieved
If a colostomy is present, the stoma site is managed separately.
Flap Transfer:
The harvested VRAM flap is tunneled through the abdominal wall or retroperitoneally to the perineal defect
The skin island is oriented to cover the defect adequately.
Vascular Anastomosis:
Microvascular anastomosis of the flap pedicle (e.g., inferior epigastric vessels) to recipient vessels in the groin or pelvic region is performed if direct in-situ perfusion is insufficient, although pedicled VRAM flaps are more common for perineal closure without microvascular expertise.
Perineal Wound Closure And Reconstruction
Flap Inset And Fixation:
The VRAM flap is meticulously inset into the perineal defect
The skin island is sutured to the surrounding perineal skin and mucosa to create a watertight closure where possible.
Muscle Coverage:
The rectus abdominis muscle portion of the flap provides bulk and vascularity, helping to obliterate dead space and promote granulation tissue formation over the exposed pelvic structures.
Abdominal Wall Reconstruction:
The donor site on the abdominal wall is closed, often with mesh reinforcement if a large defect is created, to prevent incisional hernias
The rectus muscle is divided or partially removed to create the pedicle.
Drainage:
Placement of surgical drains (e.g., Jackson-Pratt drains) in the perineal wound and potentially the abdominal donor site to manage seroma and hematoma formation and monitor for wound complications.
Colostomy Management:
If a permanent colostomy is created, its siting and management are crucial for patient adaptation and to prevent excoriation of the perineal wound with effluent.
Postoperative Care
Monitoring:
Close monitoring of flap viability (color, capillary refill, Doppler signal if available), vital signs, and fluid balance.
Pain Management:
Aggressive pain control, often with patient-controlled analgesia (PCA) or epidural anesthesia, is crucial for comfort and early mobilization.
Wound Care:
Regular dressing changes, sterile technique for drain care, and monitoring for signs of infection or flap compromise
Sitz baths are typically initiated after initial healing.
Mobilization:
Early ambulation is encouraged to prevent deep vein thrombosis (DVT), pulmonary complications, and to aid bowel function.
Nutrition:
Optimal nutritional support is vital for wound healing
high-protein diet and consideration of nutritional supplements.
Stoma Care:
Education and support for patients with a new colostomy, focusing on appliance management and skin care.
Complications
Early Complications:
Flap necrosis (partial or complete)
infection of the flap or perineal wound
seroma or hematoma formation
wound dehiscence
colostomy-related issues (e.g., skin excoriation, prolapse).
Late Complications:
Chronic perineal sinus or fistula formation
incisional hernia at the abdominal donor site
rectourethral fistula (if not completely closed)
scar contractures and functional deficits
sexual dysfunction.
Prevention Strategies:
Meticulous surgical technique, ensuring adequate vascular supply to the flap
aggressive perioperative antibiotics
careful hemostasis
adequate drainage
appropriate abdominal wall closure and reinforcement
patient selection and optimization
detailed postoperative care and monitoring.
Key Points
Exam Focus:
VRAM flap reconstruction is a key technique for complex perineal defects post-APR, particularly when primary closure is not feasible
Understanding indications, donor site, flap transfer, and common complications is vital.
Clinical Pearls:
Involve a plastic surgery or reconstructive surgeon early for complex cases
Meticulous flap perfusion assessment is paramount
Adequate drainage and meticulous wound care are crucial for success.
Common Mistakes:
Inadequate flap design or harvest leading to poor perfusion
failure to adequately debride the perineal wound
insufficient drainage
premature removal of drains
poor abdominal wall closure leading to hernia.