VRAM Flap

Dec 13, 2021 6 min read
VRAM Flap

The VRAM Flap is a Type III Mathes & Nahai myocutaneous flap. This article details its indications, anatomy, and surgical technique.

5 Key Points

1. VRAM is a Type III Mathes and Nahai Flap
2. The most common indication is for pelvic reconstruction
3. Dominant supply is from Deep Superior & Inferior Epigastric Arteries
4. Can be raised as muscle-only, myocutaneous, osseomyocutaneous (rare)
5. It obliterates dead space but results in a weakened abdominal wall.


Indications for a VRAM Flap

VRAM Flaps are primarily used in pelvic reconstruction. Prior to DIEP flaps, rectus abdominis muscle was commonly used in breast reconstruction. 

The VRAM flap is versatile to be used in breast, head & neck, and pelvic reconstruction3. Pelvic reconstruction is its primary use and indications are listed below:

  • Post-pelvic exenteration
  • Abdominoperineal resection
  • Vaginal wall reconstruction
  • Radiation-induced necrosis

Chest reconstruction uses the superior pedicle whilst pelvic reconstruction uses the inferior pedicle.

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Fun Fact: The RAM flap was first described by Holmstron in 1979. It was then popularised by Hartrampf.


VRAM Flap Anatomy

Type III Mathes and Nahai Flap based on the dominant Deep Superior and Inferior Epigastric Arteries.

Rectus Abdominis Muscles

The rectus abdominis muscles are paired, thin and flat muscle separated by the avascular line alba. It has a triangular-like shape as the base (6cm) is wider than the insertion (3cm).

VRAM Flap, VRAM anatomy, RAM Flap, vertical rectus abdominis muscle flap, rectus abdominis muscle
Anatomy of Rectus Abdominis

Key points are:

  • Origin: anterior costal cartilages VI-VIII and xiphoid process.
  • Insertion: pubic symphysis and body.
  • Innervation: intercostal nerves (segmental supply reduces its role in  functional muscle transfer)
  • Function: tension, restrict abdominal contents, and 30° of a sit-up/crunch.

Rectus Sheath

The anterior and posterior rectus sheath can be confusing in relation to the arcuate line. To understand it, it's important to understand the 3 types of structures involved:

  1. 1 arcuate line: posterior sheath & transversalis fascia junction at level of ASIS
  2. 2 sheaths: anterior and posterior sheath
  3. 3 muscles: external (EO) & internal oblique (IO),  transversus abdominis (TA)
  4. 4 Options: discussed below  

Arcuate Line, Anterior Rectus Sheath, Posterior Rectus Sheath, VRAM Flap, Anatomy
The Arcuate Line in the VRAM Flap

These structures have 4 variations

  • The anterior sheath above the AL is formed by the TA + EO.
  • The posterior sheath above the AL is formed by the IO + TA + TF
  • The anterior sheath below the AL is formed by EO + TA + IO
  • The posterior sheath below the AL is replaced by transversalis fascia (TF)

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Tip: posterior sheath is replaced by the transversalis fascia below the arcuate line.

Flap Composition

The VRAM flap is a composite myocutaneous flap consisting of three layers: skin, subcutaneous fat, and muscle. Its versatility allows it to be dissected and raised as the following:

  • Muscle-only
  • Segmen­tal muscle flap with preservation of part of the muscle
  • Myocutaneous flap with a transverse, oblique, or vertical skin island flap
  • Osseomyocutaneous (when including inferior ribs - not common)

The most commonly used myocutaneous composition consists of skin, anterior rectus sheath, rectus muscle, and the perforating vessels which connect them.

Flap Blood Supply

The rectus abdominis muscle has two major pedicles (hence Mathes and Nahai III)

  • DIEA (Inferior): dominant, external iliac artery branch.
  • DSEA (Superior): dominant, internal mammary artery branch

It is worth noting it does receive additional supply from the subcostal and intercostal arteries.

VRAM Flap, VRAM anatomy, RAM Flap, vertical rectus abdominis muscle flap, rectus abdominis muscle, anatomy
VRAM Flap Blood Supply

The superficial superior epigastric artery and the superficial circumflex artery also play a minor role.

Venous drainage of the flap

The venous drainage primary follows the arterial supply. The main veins involved are:

  • Deep Inferior Epigastric Vein
  • Deep Superior Epigastric Vein
  • Superficial Inferior Epigastric Vein

VRAM flap has a motor & sensory innervation from the 7th–12th intercostal nerves.

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Tip: Inferiorly-based pedicles can be raised as a free flap. 


VRAM Flap Technique  

The design and size of the flap depend on surgical technique, characteristics of the donor and recipient areas.

Design

  1. Identify the amount of skin island required overlying the rectus muscle.
  2. Mark an outline of the rectus muscle
  3. Incise vertically (along the muscle axis) just lateral to the midline.
  4. Consider including paraumbilical myocutaneous perforators into the paddle.

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Prepping the patient: consider getting a pre-operative CT angiogram or check for suitable perforators with a Doppler 

Dissection and Elevation

  1. Dissect down to the anterior rectus sheath, which is divided vertically.
  2. Elevate posterior, medial, and lateral portions of the sheath from muscle.
  3. Protect the anterior sheath to avoid damaging the vascular perforators.
  4. Release the muscle from its origin +/- insertion
  5. Ligate the superior epigastric vessels

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Tip: protect the anterior sheath as it contains the vascular perforators to the overlying skin.

Inset of Flap

  1. Rotate flap 180° on its DIEA pedicle
  2. Tunnel via an intraperitoneal route into the pelvis (gives more length) or extrapelvic subcutaneous route to the perineum.
  3. Assess the tension on the pedicle (not too much tension!)

Closure

  1. Decide if the anterior abdominal wall needs to be reinforced with a mesh (above the arcuate line the posterior sheath if often sufficent)
  2. Make sure the omentum is hanging normally towards/in the pelvis.
  3. Suture in 3 layers + drain insertion

Post-operative Care

A series of protocols have been designed and published. This is reflective of the different practices in departments. The following is the "Swansea" Protocol published in 20172.

  • Bedrest: 5 days in a lateral position then start mobilizing.
  • Catheter: remove Day 10
  • Sutures: remove Week 3
  • Sit out: Week 3
  • Drains: remove if <30mL/day.

Variations

VRAM flap variations do exist and are well described 1.

  • Extended VRAM flap: extra flap bulk & reach (supply by intercostals)
  • Fascia-sparing: lower hernia/bulge rate
  • Component separation donor-site closure: lower hernia & mesh rate
  • Mesh fascial closure: less fascial tension (bridged technique)
  • Include greater omental flap: reduced dead space, increase healthy tissue
  • Deepithelialized skin paddle: greater volume of flap, can act as a sling.


Discussion

Advantages

  • Ergonomics: often don't need to change the position of the patient
  • Cosmesis: can improve body contour
  • Reliability: consistent blood supply
  • Versatility: raised in different compositions, inset into different areas

Disadvantages

  • Abdominal wall weakening and increase risk of hernia.
  • Slight functional deficit
  • Difficult dissection in obese patients with increased risk of fat necrosis


References on VRAM Flap

  1. Campbell CA, Butler CE. Use of adjuvant techniques improves surgical outcomes of complex vertical rectus abdominis myocutaneous flap reconstructions of pelvic cancer defects. Plast Reconstr Surg. 2011 Aug;128(2):447-458. doi: 10.1097/PRS.0b013e31821e6fd2. PMID: 21788836.
  2. Warbrick-Smith, J., & Drew, P. J. (2018). Post-operative care of VRAM flaps for perineal reconstruction: Results of a UK practice survey and literature review. Journal of Plastic, Reconstructive & Aesthetic Surgery, 71(2), 271–273. doi:10.1016/j.bjps.2017.10.014
  3. Pelvic Reconstruction with Omental and VRAM Flaps: Anatomy, Surgical Technique, Normal Postoperative Findings, and ComplicationsTara L. Sagebiel, Silvana C. Faria, Aparna Balachandran, Justin M. Sacks, Y. Nancy You, and Priya R. BhosaleRadioGraphics201131:7, 2005-2019
  4. Blondeel N, Vanderstraeten GG, Monstrey SJ et al. The donor site morbidity of free DIEP flaps and free TRAM flaps for breast reconstruction. Br J Plast Surg 1997; 50(5): 322–330.
  5. Blondeel PN, Arnstein M, Verstraete K et al. Venous congestion and
    blood flow in free transverse rectus abdominis myocutaneous and deep inferior epigastric perforator flaps. Plast Reconstr Surg 2000; 106(6): 1295–1299.
  6. Boyd JB, Taylor GI, Corlett R. The vascular territories of the superior epigastric and the deep inferior epigastric systems. Plast Reconstr Surg 1984; 73(1): 1–16.
  7. Codner MA, Bostwick J 3rd, Nahai F, Bried JT, Eaves FF. TRAM flap vascular delay for high­risk breast reconstruction. Plast Reconstr Surg 1995; 96(7): 1615–1622.
  8. Koshima I, Soeda S. Inferior epigastric artery skin flaps without rectus abdominis muscle. Br J Plast Surg 1989; 42(6): 645–648.
  9. Mathes SJ, Nahai F. General principles. In: Mathes SJ, Nahai F (eds) Reconstructive surgery: principles, anatomy and technique. Churchill Livingstone, New York, 1997: 3–161.
  10. Taylor GI, Corlett RJ, Boyd JB. The versatile deep inferior epigastric (inferior rectus abdominis) flap. Br J Plast Surg 1984; 37(3): 330–350.


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