Anastomosis of the Superficial Inferior Epigastric Vein to the Internal Mammary Vein to Augment Deep Inferior Artery Perforator Flaps

Use of the retrograde limb of the internal mammary vein has been described previously as a lifeboat for venous congestion but not prophylactically. Maximizing the length of the deep inferior artery perforator (DIEP) flap pedicle, identifying and dissecting the superficial inferior epigastric vein proximally in every patient, and taking advantage of the retrograde internal mammary vein are all technical details that facilitate the additional venous anastomosis and flap inset. Performing a second venous anastomosis routinely using the superficial inferior epigastric vein to the retrograde internal mammary vein helps with flap inset.

Key points

  • Use of the retrograde limb of the internal mammary vein has been described previously as a lifeboat for venous congestion but not prophylactically.

  • Maximizing the length of the deep inferior artery perforator (DIEP) flap pedicle, identifying and dissecting the superficial inferior epigastric vein proximally in every patient, and taking advantage of the retrograde internal mammary vein are all technical details that facilitate the additional venous anastomosis as well as flap inset.

  • Performing a second venous anastomosis routinely using the superficial inferior epigastric vein to the retrograde internal mammary vein helps with flap inset by narrowing the width of the breast mound.

  • Routine venous augmentation is simple without additional morbidity to the procedure and in the authors’ experience has offset the incidence of venous congestion and fat necrosis.

Introduction

Venous congestion is a major pitfall in the deep inferior artery perforator (DIEP) flap for breast reconstruction. No clear evidence has supported routine venous augmentation, although several studies have shown a potential clinical benefit leading to decreased venous congestion and fat necrosis. Secondary venous recipients described have included a second internal mammary vein if present, the thoracodorsal vein, cephalic vein, thoracoacromial vein, or external jugular vein turndown. Use of each of these veins as a recipient has been associated with additional dissection beyond what is routinely done for DIEP flap inset, increasing operative time and adding morbidity to the procedure.

Use of the caudal (retrograde) limb of the internal mammary vein (IMV) has been described as a lifeboat for venous congestion but not prophylactically. Also, several studies have evaluated the flow in the retrograde IMV. This anastomosis is feasible due to the fact that the IMV is valveless. Since September 2014, the authors have routinely performed a second venous anastomosis predominantly with the SIEV (superficial inferior epigastric vein) to the caudal IMV. This article reviews the authors’ experience using this technique and shares their algorithm for routine venous augmentation of DIEP flap using the SIEV and caudal IMV.

Introduction

Venous congestion is a major pitfall in the deep inferior artery perforator (DIEP) flap for breast reconstruction. No clear evidence has supported routine venous augmentation, although several studies have shown a potential clinical benefit leading to decreased venous congestion and fat necrosis. Secondary venous recipients described have included a second internal mammary vein if present, the thoracodorsal vein, cephalic vein, thoracoacromial vein, or external jugular vein turndown. Use of each of these veins as a recipient has been associated with additional dissection beyond what is routinely done for DIEP flap inset, increasing operative time and adding morbidity to the procedure.

Use of the caudal (retrograde) limb of the internal mammary vein (IMV) has been described as a lifeboat for venous congestion but not prophylactically. Also, several studies have evaluated the flow in the retrograde IMV. This anastomosis is feasible due to the fact that the IMV is valveless. Since September 2014, the authors have routinely performed a second venous anastomosis predominantly with the SIEV (superficial inferior epigastric vein) to the caudal IMV. This article reviews the authors’ experience using this technique and shares their algorithm for routine venous augmentation of DIEP flap using the SIEV and caudal IMV.

Patients and clinical methods

The senior author has performed 30 DIEP flaps since September 2014, in which 2 venous anastomoses were performed in each flap irrespective of the presence or absence of intraoperative venous congestion. Thirty flaps prior to September 2014 with 1 anastomosis were included in the control limb. Only single or double perforator DIEP flaps were included in this review. Muscle-sparing transverse rectus abdominis muscle (TRAM) flaps and free TRAM flaps were excluded.

Clinical results

Patient demographics were comparable between both groups ( Table 1 ). The average body mass index (BMI) was around 30 in both groups (30.4 vs 30.1), and the patients were comparable in their co-morbidities, which included diabetics, hyperlipidemia, high blood pressure, and previous abdominal surgeries. Average age was also comparable (47.5 vs 48.5 years old), and there were equal numbers of smokers in both groups.

Table 1
Patient demographics
Patient Demographics Single Venous Anastomosis Double Venous Anastomosis
Average age 47.5 48.53
Average weight 80.5 kg (54–114) 83.9 kg (55–120)
Average BMI 30.4 (25.2–40.1) 30.1 (21.2–43.2)
Diabetes 3 (10%) 4 (13.3%)
Hyperlipidemia 10 (33.3%) 8 (26.7%)
History of smoking 4 (13.3%) 4 (13.3%)
Hypertension 6 (20%) 8 (26.7%)
Previous abdominal surgery or liposuction 8 (26.7%) 8 (26.7%)

The average length of the DIEA/DIEV pedicle was comparable in both groups (11.27 vs 11.89 cm). The SIEV length was also similar. Additionally, other flap characteristics were comparable between the 2 groups. Average flap weight was slightly higher in the 2-vein group (830 vs 690 g). There was no flap loss overall in either group. The intraoperative venous congestion rate was 6.7% in the single venous anastomosis group and 13.3% in the venous augmentation group ( Table 2 ). There was no postoperative venous congestion or re-exploration in the group in which routine venous augmentation was performed when compared with the single venous anastomosis group (0% vs 6.7%). Clinical rates of fat necrosis were decreased from 10% to 3.3%.

Table 2
Comparison of flap characteristics, technical details, and outcomes between single and double venous anastomoses groups
Single Venous Anastomosis Double Venous Anastomosis
Unilateral 4 (13.3%) 4 (13.3%)
Immediate 6 (20%) 8 (26.6%)
Single perforator DIEP 22 (73.3%) 25 (83.3%)
Average pedicle length 11.27 cm (9–13) 11.89 cm (10–13)
SIEV length 7.55 cm (6–8) 7.46 cm (6–12)
Average flap weight 690.9 gm (318–1245) 830.88 gm (427–2024)
Second venous anastomosis 2 (6.7%) 100%
Intraoperative venous congestion 2 (6.7%) 4 (13.3%)
Postoperative venous congestion 2 (6.7%) 0 (0%)
Re-exploration 2 (6.7%) 0 (0%)
Flap survival 30 (100%) 30 (100%)
Venous augmentation with second anastomosis 4 (13.7%) 30 (100%)
Fat necrosis 3 (10%) 1 (3.3%)

The needs and technical points for venous augmentation

Disadvantages of Current Deep Inferior Artery Perforator Flaps

One of the few disadvantages of the DIEP flap is the greater incidence of venous congestion and fat necrosis. Reported rates of venous congestion in DIEP flaps range from 3% to 25%. Venous congestion remains the most common cause of flap loss in DIEP breast reconstruction. The highest incidence of venous congestion is in the intraoperative period.

Vascular Anatomy and the Reason for Increased Venous Congestion in Deep Inferior Artery Perforator Flaps

The DIEP flap is associated with higher rates of venous congestion when compared with other flaps because of limitations in the intrinsic vascular anatomy of the DIEP flap. In the majority of patients, the DIEA remains the dominant artery. However, the same cannot be said of the venous anatomy. Carramenha and colleagues reported that the venous drainage of the skin paddle in a DIEP as well as TRAM flap is largely dependent on the SIEV rather than the deep system in the normal state. When the superficial system is divided during the process of flap harvest, this directs the venous drainage caudally via the connecting vascular network between the superficial and the deep system, with the venous return eventually draining via the deep system. This was further studied by Blondeel and colleagues, who examined the interconnecting network between the superficial and deep systems. Variable vascular communicating patterns were noted across subjects, which explain the unpredictable occurrence of venous congestion. The rate of intraoperative venous congestion in Blondeel’s series was 2%. Various studies in the interim have reported varying rates of venous congestion ranging from 2% to 27%. This difference could in part be explained by differing flap elevation techniques, adequacy of the primary venous anastomosis, and varying criteria defining venous congestion by different surgeons.

It is difficult to predict the dominance of the superficial system even with preoperative computed tomography (CT) or magnetic resonance (MR) angiography ( Fig. 1 ). CT angiography (CTA) allows for a snapshot of the abdominal wall vascular anatomy when the patient is in a supine position and under baseline hemodynamic parameters. However, CTA lacks information on the physiologic flow dynamics after flap elevation, when the patient is under general anesthesia in the flap. Sadik and colleagues found no correlation between the calibers of the SIEV on CTA with superficial system dominance. They recommended judicious harvest of the SIEV in every DIEP flap irrespective of the size of the SIEV. These findings were contradictory to previous data, which supported the correlation between the SIEV caliber and superficial dominance. Hence, although CTA remains a valuable tool to guide perforator selection in flap harvest, it is unreliable in predicting venous system dominance and risk of congestion.

Nov 21, 2017 | Posted by in Dental Materials | Comments Off on Anastomosis of the Superficial Inferior Epigastric Vein to the Internal Mammary Vein to Augment Deep Inferior Artery Perforator Flaps
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