Sternal Edges Research Articles

Delayed Sternal Closure Following Operation of Type-A Acute Aortic Dissection

In 7 patients with type-A acute aortic dissection, the sternum was not closed because of excessive hemorrhage after grafting. Only the skin was closed, the sternal edges being left apart and the anastomotic sites being packed with dry gauze in the mediastinum to control the life-threatening sequela. All patients except for 1 who died of uncontrollable bleeding had successful delayed sternal closure within three days after the first operation. One patient who had late chest wound infection died, but the remaining 5 patients had neither mediastinitis nor chest wound infection and are now in good or fair clinical condition. The authors conclude that delayed sternal closure is an effective method of dealing with excessive postbypass bleeding following operation of type-A acute aortic dissection.

Raised end-expiratory alveolar pressures during cardiac surgery

Increased end-expiratory pressure (EEP) is usually associated with expiratory obstruction. By pressing the "expiratory pause hold" button on the Servo ventilator 900C, EEP was measured at four stages during coronary bypass surgery: before sternotomy (I), after sternotomy with the sternal edges fully retracted (II), after completed extracorporeal circulation, sternal edges still retracted (III) and after sternal closure (IV). Five patients had EEP values > 3 cm H2O at stage I. EEP decreased after opening the sternum and was still low after extracorporeal circulation (stages II and III). However, sternal closure was associated with large increases in EEP (maximum value 22 cm H2O). Typically, patients in whom EEP exceeded 5 cm H2O at stage IV also had raised values at stage I. These patients had obstructive preoperative spirometry patterns and tended to be of shorter stature in relation to weight than patients in whom EEP did not exceed 5 cm H2O. The changes in EEP are believed to be caused by changes in lung volume as a result of opening and closing the sternum and by increased lung water after extracorporeal circulation.

Reduction of sternal infection by application of topical vancomycin

Sternal or mediastinal infection after heart operations occurs infrequently but carries a high cost in money, morbidity, and mortality. At our hospital, Staphylococcus nonaureus causes most of these infections and is uniformly sensitive to vancomycin. In a prospective study of 416 patients having cardiac operations, randomized by hospital record number, topical vancomycin was applied to the cut sternal edges in 223 patients (group V) and was omitted in the control group (C) of 193 patients. The vancomycin was applied in a hemostatic paste of topical thrombin and powdered absorbable gelatin; in the control group only the hemostatic paste was applied. All patients received prophylactic systemic antibiotics for 2 days. Sternal infection occurred in one patient in group V (0.45%) and in seven patients in group C (3.6%) (p = 0.02). Infection also correlated with longer operative times (p = 0.027). By multivariate testing, vancomycin (p = 0.013) and shorter operative times (p = 0.014) independently predicted reduced infection rates. In the one patient with an infection in group V, Staphylococcus aureus was cultured; this organism was also cultured in two patients in group C, with Staphylococcus nonaureus being the culprit in the other five patients with sternal infections in group C. Topical vancomycin applied to the cut sternal edges reduces the risk of postoperative sternal infection.

Repeat Median Sternotomy in Pediatrics: Experience in 164 Consecutive Cases

One hundred thirty-eight children underwent 164 operations through repeat median sternotomy. Ages ranged from 4 months to 21 years (mean, 8.6 ± 5.0 years). The technique consisted of opening the sternum with chisel and mallet, avoidance of sudden separation of sternal edges and blunt dissection, elimination of the electrocautery during lysis of adhesions, and judicious use of fresh blood and components. Several variables were analyzed comparing the initial and repeat procedures on each patient. Time from incision to bypass was an hour longer with the repeat procedure (174 ± 45 minutes versus 96 ± 37 minutes). Operative transfusions and postoperative bleeding (first 48 hours) were not significantly different between the two procedures. Cyanosis, however, significantly increased bleeding in both groups. There were eight injuries (5%) at reoperation. During sternal reentry in 2 patients, a tear occurred in a valved conduit coursing underneath the sternum. A right ventricular tear occurred in 1 patient while the sternal edges were being separated. Ventricular fibrillation was noted in 2 patients during lysis of adhesions with the electrocautery used early in the series. Intimal disruption occurred in two valved conduits during intraoperative manipulations. An aortic tear occurred and was repaired without cardiopulmonary bypass. There were 13 (8%) hospital deaths, all unrelated to the technique. We believe that the current approach can be a valuable alternative for surgeons dealing with repeat median sternotomy in children.

Bilateral Internal Mammary Artery Mobilization and Sternal Healing

Four instances of mediastinal wound infection occurred in 100 patients who underwent bilateral internal mammary artery (IMA) mobilization for coronary bypass. Debridement of 3--5 mm of the sternal edges was performed 6--18 days after the primary operation, and 2 patients required additional, anatomically limited debridement. Wounds were allowed to heal by secondary intention. The wounds of 3 patients healed by 4, 7, and 16 months; they had patent grafts at the postoperative or 1-year catheterization; and they returned to work and are free of angina. The fourth patient died of renal and respiratory failure 3 months after the operation; his wound was healing and had not required additional debridement. These observations indicate that bilateral IMA mobilization does not result in avascularity of the sternum, which required only limited debridement and quickly formed granulation tissue from the periosteum and marrow.

Treatment of mediastinitis in children after cardiac surgery. A study of 20 cases.

Twenty-three cases of mediastinitis after cardiac surgery in children were treated by us between 1973 and 1976. Three patients died within 6 hours of admission. Treatment used in the tweny other cases are discussed. The mean age of the patients was three years and three months. The mediastinitis was evident an average of twelve days after extracoporeal circulation. A staphylococus was always responsible for the infection. Treatment was a combination of surgery, antibiotics and respiratory and nutritional supplies. The surgical treatment consisted of a careful mediastinal cleansing with resection of the sternal edges. In fifteen patients the thorax was closed after surgery, and an irrigation system installed using a solution of 4% Dakin in physiologic saline. Recovery was simple in 5 patients. In the 10 other patients of this group the thorax had to be reopened; one patient died after 90 days from Serratia marcescens endocarditis. The thorax was left open initially in five patients: one patient of this group died from candida endocarditis. All patients needed endotracheal ventilation through a nasotracheal tube (7 to 90 days of ventilation). Treatment with bactericidal antibiotics was pursued for three months and a monotherapy was kept for nine months. After reviewing the observed complications, our methods and results are compared with others in the literature.

Surgical correction of pectus excavatum

It has been observed that some patients who had correction of funnel chest deformity by methods which failed to provide fixed elevation of the involved sternal segment developed progressive sagging in later years in spite of looking good at the operating table. This has led to the adoption of a new technique of double sternal support. This procedure has resulted in 35 of 37 children (94%) being classified as excellent or satisfactory. This double support was initially established in 1959 by overlapping the upper transsected sternum while maintaining elevation of the lower end with a soft tissue sling of perichondrium and intercostal muscle. Beginning in 1961, a rigid bridge of rib or stainless steel bar was substituted at the lower end of the sternum. This has provided better support and the current preference of using the steel bar has been validated in this group of patients. The few disappointments were related to removal of the bar earlier than desired, failure to excise all the protruding sternal cartilage stumps or rib graft tips and inability to cover the lateral sternal edges with pectoral muscles. If possible, the steel bar should not be removed before 12 mo. When these pitfalls were avoided, the results were almost uniformly excellent. The wisdom of excising all depressed cartilaginous segments, as advocated by Ravitch in 1949, 4 has been substantiated. A submammary transverse incision has provided an excellent cosmetic appearance. The morbidity has been low and the mortality zero. In spite of the absence of objective evidence of cardiopulmonary dysfunction, there seems to be an almost uniform improvement in appearance and in patient activity following successful correction of the funnel chest. The latter may be as much a psychological response as a physiologic one. The low morbidity, satisfactory long term results, and general improvement in the patient's body image and outlook on life indicate the need to offer correction of the severe pectus excavatum deformity to low risk children.

Radiolucent Retractor for Operative Coronary Angiography

A new retractor has been designed for sternal separation during cardiac operations. This retractor has the advantage of radiolucent blades that allow visualization of the entire heart by roentgenographic techniques without compromise of surgical exposure during the course of operation. The retractor also has swivel blades that provide excellent conformity to the sternal edges without pressure points, which tend to produce fractures.