Successful Flap Revascularization Following Late Pedicle Avulsion

Dear Sir:

We have recently encountered a patient who suffered complete avulsion of arterial and venous anastomoses of her deep inferior epigastric perforator (DIEP) flap at 2 weeks after the original operation. The flap survived following emergency vein graft revascularization.

Interval breast reconstruction was performed on a 51-year-old female. She had previously undergone mastectomy, followed by adjuvant chemotherapy, but no radiotherapy. She reported no past medical history, smoked 10 cigarettes per day, and her body mass index (BMI) was 37 kg/m². Her bra target size for reconstruction was 42D. Breast reconstruction was performed using a free DIEP flap. The estimated weight of the flap was 1.5 kg. The internal mammary artery and a single vein were exposed by the removal of the 3rd costal cartilage, and divided distally. Anastomosis was made to a single large calibre medial perforator using 9-0 Ethilon (Ethicon™).

She was advised to wear a brassiere at all times for 4 weeks, but at home 15 days after the operation, removed her brassiere to take a shower. She noticed an increase in the volume of the breast, felt light-headed and collapsed. She was readmitted as an emergency. On arrival, she was drowsy but oriented, with signs of hypovolemic shock. The DIEP flap had complete loss of flow centrally, with sluggish flow peripherally. Immediate surgical exploration revealed a 700-ml hematoma and complete avulsion of both arterial and venous anastomoses. Vascular clamps were applied to the bleeding recipient vessels. Inspection of the avulsed ends of the flap vessels revealed broken suture loops with the knots intact, suggesting mechanical force as the cause of the anastomotic disruption.

After a period of perioperative resuscitation, the flap was revascularized. The flap vessels appeared to be of adequate length for tension-free anastomosis, but in view of the presumed etiology, interpositional vein grafting was used to both artery and vein. Following this revascularization, good flow was restored to the flap. In the immediate postoperative period, flow to the flap was sensitive to position: although the flap showed normal perfusion when the patient lay flat, it became congested when she sat up. Apart from a small area of breakdown which settled with dressings, the entire flap survived.

Breast reconstructions with abdominal tissue have the advantage of greater volume, and a more natural shape. However, when performed by microvascular transfer, there is the disadvantage that a heavy and pendulous flap, not supported adequately, can exert considerable traction on the pedicle. Lesser traction forces may result in postural variation in arterial inflow and venous drainage. In more extreme cases, one or both of the microvascular anastomoses may be completely avulsed.

Reports of pedicle avulsion in breast free flaps are few. Pedicle avulsion at 3 days with loss of the flap has been described in a lateral transverse thigh free flap.[1] Partial arterial avulsion, with intact venous anastomosis has been reported at 5 days in a DIEP flap, with survival after microsurgical revision.[2] Pedicle avulsion at 8 days has been described for a superior gluteal artery perforator (S-GAP) flap used for breast reconstruction.[3] In this case, although re-anastomosis was not possible, the flap survived.

There are additional reports indicating that disruption of the pedicle in free flaps generally does not necessarily result in flap loss. A series of seven pedicle disruptions has been reported between 8 and 18 days from anastomosis.[3] Complete or partial survival of six of these flaps without re-anastomosis was attributed to ischemia-driven angiogenesis. In another retrospective study of ten late pedicle disruptions, Salgado et al.[4] concluded that the vascularity of the recipient bed and history of radiotherapy were the main factors determining flap survival without re-anastomosis.[4] This series included one TRAM flap in which the pedicle was divided at 3 months. The anastomosis was not repaired and one-third of the flap underwent necrosis.

This case highlights the importance of 24-hr mechanical support of large flaps for a prolonged period postoperatively. In the event of pedicle avulsion, we strongly recommend vein graft revascularization, which may be successful even after such a potentially life-threatening complication.

REFERENCES

• 1 Elliott L F, Beegle P H, Hartrampf C R. The lateral transverse thigh free flap: an alternative for autologous-tissue breast reconstruction.  Plast Reconstr Surg. 1990;  85 169-178
• 2 Gahankari D, Malyon A, Weiler-Mithoff E M. Avulsion of vascular anastomosis in free-flap breast reconstruction.  Br J Plast Surg. 2001;  54 167-168
• 3 Heymans O, Lemaire V, Preud'Homme L, Nelissen X, Verhelle N. Perte du pedicule nourricier d'un lambeau libre: etude clinique sur 8 cas.  Ann Chirurgie Plastique Esthetique. 2003;  48 205-210
• 4 Salgado C J, Smith A, Kim S et al.. Effects of late loss of arterial inflow on free flap survival.  J Reconstr Microsurg. 2002;  18 579-584