Objectives: The incidence of infected sternotomy wounds after
median sternotomy for cardiovascular surgery is about (0.5% to
5%) and it is associated with significant morbidity and a long period
of treatment. Today, muscle flaps, such as the Pectoralis major, are
widely accepted as a mainstay of reconstructive options. A wide
variety of modifications of the Pectoralis muscle flap for coverage
of sternal defects are available depending upon the location of
defect use of internal mammary artery. We would like to share our
experience with Pectoralis major muscle flaps to cover the sternal
Methods: The sternal defects were thoroughly debrided and
the defects were covered with Pectoralis major flap. Depending on
the location of the defect the Pectoralis major flaps were elevated
and coverage of defects done.
Results: The study of 25 patients with Pectoralis major flaps
for sternal defects done from July 2010 to January 2012 followed
up for 6 months. There were no recurrences.1 patient developed a
hematoma which required evacuation and 2 patients had suture line
skin necrosis which was managed conservatively with dressings.
Conclusions: The Pectoralis major flap is a practical and
effective method in the reconstruction of the Sternal defect caused
CABG. It not only provides sufficient volume to fill the entire
mediastinum but also affords resolution of the infected wound with
Pectoralis major muscle flap; Chest wall defects; Post CABG
The treatment modalities for sternal defects following CABG
include conservative methods of open wet dressing, occlusive
continuous irrigation or vacuum-assisted closure etc and surgical
treatment with flaps of the Pectoralis major, Rectus abdominis,
Latissimus dorsimuscle or Omentum [1-17]. However, the general
consensus is still valid that muscle flap obliteration of dead space
resulting from debridement of potentially infected tissue is essential
in obtaining wound closure in a significant number of cases [9,13-15,18].
The wound dehiscence following CABG is combined result of
decreased vascularity following the usage of internal mammary
artery, Diabetes and wound infection in presence of sternal wires
which mandates strict glycemic control, debridement and removal of
wires as well as good coverage in its treatment [19-21]. These patients
are mostly diabetics and have other medical morbidities and on anti
coagulant therapy, which needs to be stopped for the surgery [3,5,22].
These cases are often referred to us after the conservative
approaches have failed, and frequently after attempts of incomplete
debridement and secondary closure in an effort to retain the sternal
The use of muscle flaps for coverage of these defects give the
advantage of stable coverage, increase the vascularity of the wound
and also in case of breakdown of the wound prevents the exposure of
vital structures [13,15].
Pectoralis muscle has stood the test of time in the coverage of these
defects . Its blood supply from the thoraco acromial vessels allow
it to be advanced to the sternal defect in its upper third, especially
on the side of usage of the Internal Mammary Artery. The segmental
vessels that supply it along its medial border allow the muscle to be
turned over to cover the middle and part of lower third sternal defect.
The distal most part of the defect was covered with adipofascial flaps
based on the epigastric arcade .
Materials and Methods
Twenty-five patients of CABG who developed sternal dehiscence
and defect from July 2010 to January 2012, treated with Pectoralis
major muscle flap procedure were studied. All patients were managed
conservatively with regular dressings, antibiotics according to culture
and sensitivity and the patients were referred 10 days to 2 months
after CABG to the plastic surgery department. In 10 patients several
surgical debridement or attempts at closure were performed before
the definitive operation. All patients underwent routine pre operative
evaluation and swabs for culture sensitivity. Antibiotics were started
accordingly and patients were posted for surgery. CT scans of
thorax were performed to see for the extent of the infection. In all
patients single stage debridement,with definitive flap surgery was
performed through the CABG incision, after all wirings and infected
osseocartilaginous debris were removed, which was more on the left
side, but complete sternectomy was not viewed as essential in all
cases. At the completion of debridement and thorough irrigation, the
resulting defect was reassessed for the flap selection (Figure 1).
Figure 1: Debridement specimen of the costal cartilages and sternum.
From the edge of the sternal defect, the skin and subcutaneous
flap was elevated, extending to the clavicle, anterior axillary line, and
inferior intercostal margin, thus exposing the anterior surface of the
Pectoralis muscle. The undersurface of the Pectoralis major muscle
was then freed from the rib cage and its costal insertions in its entirety
on the side of the used internal mammary artery (left side). Superiorly,
half to two thirds of the clavicular origin was detached medial to
the thoracoacromial pedicle and advanced without resection of the
humeral insertion. This flap was used to cover the upper sternal
defect. The Pectoralis muscle on the side of intact Internal Mammary
Artery(right side) was cut proximally and turned over to cover the mid sternal and part of the lower sternal defects. To cover the most caudal part of the sternal defect, adipofascial turnover flaps from the rectus sheath were used. The flaps were sutured securely with absorbable sutures, and a chest tube was inserted into the pleural space whenever needed by the cardiothoracic surgeon. Suction drains were inserted below the muscle flaps and skin flaps (Figures 2-4).
Figure 2: Pre and post operative photographs of Right turn over Pectoralis major flap with adipofascial flap.
Figure 3: Pre and post operative photographs of left advancement and Right turn over Pectoralis major flaps with adipofascial flap.
Figure 4: Pre and post operative photographs of bilateral Pectoralis major myocutaneous advancement flaps.
Of the 25 patients, were 21 males and 4 females, with the mean ages were 60.3 years and 61.2 years, respectively. All underwent left internal mammary artery usage for CABG. The average duration between the sternotomy and the occurrence of dehiscence was 18.3 days, and the interval from the diagnosis of dehiscence to the flap operation was, on average, 1.1 months. The average follow-up period after the flap operation was 6 months. With regard to the bacterial organisms cultured from the wounds, methicillin-resistant Staphylococcus aureus (MRSA) was found in 6 patients, S aureus was found in 3 patients, pseudomonas ws found in 4, klebsiella were cultured in 5 and acinetobacter in 5 patients, and no organisms were detected in 3 patients. In the above patients an advancement Pectoralis muscle only was used in 1 patient, only turnover flap used in 6, the Pectoralis muscle advancement with turnover done in 11 patients, the Pectoralis muscle advancement with turnover and adipofascial flaps were done in 4, turnover and advancement with adipofascial flaps in 2. The Pectoralis major myocutaneous advancement was done in 1 patient who had previous debridement and the right IMA patency was doubtful. All these patients who were followed up for 6 months none of them developed recurrence. Skin necrosis was seen in two patients and both were treated conservatively with dressings and they healed without any additional surgical procedure. One patient developed hematoma on 5th postoperative day which had to be drained surgically but no bleeding vessel was identified.
The post CABG sternal defect is a potentially devastating occurrence and is associated with diabetes, the local ischemia following utilization of the Internal Mammary Artery and complicated by wound infection. The Internal Mammary Artery used for bypass lies in this infected milieu and potentiates the urgent coverage of these defects. Though various techniques have been described for these defects the Pectoralis major muscle remains the choice as it may be explored through the same incision, doesn’t need change of position and provides a robust and reliable cover [10,11].
The sternal wounds are infected with a wide variety of organisms, bacterial and fungal. The MRSA infections of these wounds are devastating. The use of antibiotics according to the sensitivity and thorough debridement is critical to reduce the infective counts [19-21].
The sternal dehiscence may be managed conservatively by regular dressings antibiotics and use of vaccum assisted closure [1,2]. The surgical management is often preferred as the sternal defect post CABG requires early coverage. There are often previous attempts to close these defects secondarily or attempts to mobilize the Pectoralis muscles to midline, these attempts may damage the parasternal perforators of the Internal Mammary Artery on the intact side. This was the case in one case who had repeated attempts of closure which had given way resulting in a huge defect. This patient required removal of wires thorough debridement and robiscek wiring to stabilize the chest wall followed by a Pectoralis myocutaneous advancement [1,6,7,10-12].
The lower most part of the sternal defect is most difficult to cover, which may further be made difficult by debridement of the left lower cartilages. These defects were covered by omental flaps [16,17], Rectus abdominis flaps and bipedicled rectus abdominis and Pectoralis major flap but they cause significant morbidity [10,11,23]. We have devised a new technique by using the adipofascial turnover flaps elevated over the rectus sheath based on the epigastric arcade [8,23].
The most common complication we encountered was necrosis of the skin at suture line which was managed conservatively. The hemostasis was strictly maintained throughout the surgery to avoid hematoma. One patient developed hematoma on 5th day and was evacuated and fresh drains were placed though no bleeder was identified on the re exploration.
The Pectoralis major muscle flap is the work horse flap for the reconstruction of Post CABG sternal defects. The key to success is early and appropriate diagnosis of the problem, proper debridement of all devitalized tissue and coverage by vasularized tissue. The Flap elevation is easy and fast, and the flap may be modified based on the need and extent of the defect. Moreover, the adipofascial turnover flaps have proved to be very effective in the lower sternal defect coverage.