Authors: Emma Tubæk Nielsen, MD., Caroline Lilja, MD., and Magnus Balslev Avnstorp, MD.

Biomechanical properties

The gracilis muscle is long and slim, measures around 25 cm in length, 6 cm in proximal width and 4 cm in distal width. It is often wider if the patient is male and/or physically fit.

The intramuscular nerve branches allow for the muscle to be thinned and for segments to be removed, to fit the muscle as needed before the transfer.

If the muscle is harvested as a musculocutaneous flap, it is important to be aware of skin quality. The arterial perforators vary in distribution and number, and the skin on the distal 1/3 is reported to be unreliable due to lack of perforators.^2,3

The gracilis flap has a wide range of applications, especially when a functioning free muscle flap is required. Some of its applications are listed below:

• Breast reconstruction.
• Upper and lower extremity reconstruction.
• Neovagina reconstruction.
• Dynamic restoration/reanimation of midface in case of facial paralysis.
• Closure of peri-anal fistula
• Restoration of anogenital sphincter function
• Surgical defects requiring soft tissue filling.^1,4

Preoperative considerations

Any history of trauma or surgery related to the flap dissection area of inner thigh.

Evaluation of the vascular pedicle using a doppler or angiography could have relevance in patients presenting with cardiovascular disease.¹

In addition, the advantages and disadvantages of the flap should be considered prior to dissection.

Advantages

• Dissection is relatively straightforward.
• The anatomy is relatively consistent, and the flap has a reliable vascular pedicle.
  • The motor nerve is located near the pedicle of the flap, making it a great choice for functional muscle flap transfer.
• The size of the muscle enables coverage of medium sized defects.
• The properties of the muscle are preserved if expanded.⁵
• Donor site location enables two-team surgery when recipient site is located at the thorax/breast, upper extremities or face.⁶
• The donor site hides subsequent scarring on the inner thigh.
• If the innervation is preserved, the flap can be used for reconstruction with restoration of muscle function is desired.⁵
• Morbidity of the donor site is relatively low.⁶
• When denervated, the following muscle atrophy improves the contour of the flap and its aesthetic outcome.⁶

Disadvantages

• In cases with larger defects, the muscle size may be insufficient to cover the defect.⁵
• The skin of the distal upper limb is often thin and not always reliable.
• Subsequently to harvest, muscle strength of the lower limb may be diminished.³

Patient Information

The patient is informed about the risks associated with the procedure, and possible outcomes subsequently, including:

• Donor site complications such as:
  • Pain
  • Infections.
  • Bleeding.
  • Seroma.
  • Scarring.
• Long-term complications such as:
  • Dysesthesia.
  • Pain.
  • Functional difficulties.¹

References

1. Kim, Jason H. Gracilis tissue transfer. Medscape, Clinical procedures. 24.07.2019. Link:https://emedicine.medscape.com/article/880792-overview#a2
2. Fattah A. Y. et al. A three-dimensional study of the musculotendinous and neurovascular architecture of the gracilis muscle: application to functional muscle transfer. Journal of Plastic, Reconstructiv & Aesthetic Surgery, 2013.  
3. Universitat Autònoma de Barcelona. Dissection in Fresh Cadaver. European Master’s degree in surgical oncology, reconstructive and aesthetic breast surgery (MRBS).
4. Buntic, Rudy. The Gracilis Flap. Microsurgeon, Flaps. Link: https://www.microsurgeon.org/gracilismuscle
5. Dr Zezo. Gracilis flap. Plastic Surgery Key. 03.03.2017. Link: https://plasticsurgerykey.com/gracilis-flap/
6.  Franco M. J. et al. Lower Extremity Reconstruction with Free Gracilis Flaps. J Reconstr Microsurg 2017.