Sternotomy Group Research Articles

Comparison of staged thoracoscopy and median sternotomy for lung volume reduction

Background. Lung volume reduction operations have proved beneficial for emphysematous patients, but questions remain about the role of a unilateral procedure. Methods. Fifty patients were prospectively enrolled in a lung volume reduction surgery program for emphysema with staged unilateral video-assisted thoracoscopic procedures (VATS group). These patients were compared with 29 patients having bilateral lung volume reduction procedures by median sternotomy. Results. The VATS group was slightly older and had shorter 6-minute walk distances, but otherwise the two groups were similar. Hospital stays were shorter for each unilateral VATS procedure, but the total of the two hospital stays was longer than the stay for the sternotomy group (21.1 versus 14.8 days). Complications were comparable, there were no in-hospital deaths, and there was significant difference in the 1-year mortality rate (VATS, 6% versus sternotomy, 13.8%; p = 0.137). Functional test results were comparable between the groups with improvements in percent predicted forced expiratory volume in 1 second (VATS, 41%, and sternotomy, 40%), 6-minute walk distances (VATS, 48%, and sternotomy, 26%), dyspnea scores, and acid base measurements. Conclusions. Staged lung volume reduction operations do not appear to offer any measurable advantages over a single hospitalization and bilateral lung volume reduction procedures.

Toracotomia minimamente invasiva nas intervenções cirúrgicas valvares

Introdução: é tema atual a realização de procedimentos cirúrgicos por minitoracotomias que, inicialmente utilizadas para operações de revascularização do miocárdio, têm sido também propostas como acesso às operações valvares. O objetivo deste trabalho é analisar resultados da minitoracotomia em relação à técnica tradicional nas intervenções valvares, em estudo prospectivo. Casuística e métodos: entre novembro de 1996 e fevereiro de 1998, dois grupos, 8 pacientes operados por minitoracotomia (Grupo 1) e 8 controles (Grupo 2) equiparáveis nas variáveis sexo, idade, peso/altura, classe funcional pré-operatória, doença de base e operação proposta, foram submetidos a reparo ou troca valvar aórtica ou mitral. Os pacientes do Grupo 1 foram operados através de incisão paraesternal direita de até 8 cm, com circulação extracorpórea (CEC) estabelecida através de canulação arterial e venosa femorais e os do Grupo 2 (controles) por esternotomia mediana. Ambos os grupos foram acompanhados até a alta hospitalar. Resultados: Os parâmetros avaliados no trans-operatório e pós-operatório, bem como a análise estatística constam nas Tabelas 1 e 2. Não ocorreram óbitos imediatos. Duas complicações foram registradas: um infarto per-operatório e um acidente vascular cerebral no Grupo 2. Conclusão: os resultados parciais permitem inferir que a abordagem através de pequenas toracotomias é factível sem aumento na morbimortalidade, do tempo cirúrgico ou da estadia hospitalar. Possíveis vantagens objetivas de um método em relação a outro, exceto o aspecto estético, não estão evidentes até esta etapa do estudo.

Atelectasis is a major cause of hypoxemia and shunt after cardiopulmonary bypass: an experimental study.

Respiratory failure after cardiopulmonary bypass (CPB) remains a major complication after cardiac surgery. The authors tested the hypothesis that atelectasis is an important factor responsible for the increase in intrapulmonary shunt after CPB. Six pigs received standard CPB (bypass group). Six other pigs had the same surgery but without CPB (sternotomy group). Another six pigs were anesthetized for the same duration but without any surgery (control group). The ventilation-perfusion distribution was measured with the inert gases technique, extravascular lung water was quantified by the double-indicator distribution technique, and atelectasis was analyzed by computed tomography. Intrapulmonary shunt increased markedly after bypass but was unchanged over time in the control group (17.9 +/- 6.2% vs. 3.5 +/- 1.2%; P < 0.0001). Shunt also increased in the sternotomy group (10 +/- 2.6%; P < 0.01 compared with baseline) but was significantly lower than in the bypass group (P < 0.01). Extravascular lung water was not significantly altered in any group. The pigs in the bypass group showed extensive atelectasis (32.3 +/- 28.7%), which was significantly larger than in the two other groups. The pigs in the sternotomy group showed less atelectasis (4.1 +/- 1.9%) but still more (P < 0.05) than the controls (1.1 +/- 1.6%). There was good correlation between shunt and atelectasis when all data were pooled (R2 = 0.67; P < 0.0001). Atelectasis is produced to a much larger extent after CPB than after anesthesia alone or with sternotomy and it explains most of the marked post-CPB increase in shunt and hypoxemia. Surgery per se contributes to a lesser extent to postoperative atelectasis and gas exchange impairment.

Control of Postoperative Pain by Transcutaneous Electrical Nerve Stimulation After Thoracic Operations

Background. Transcutaneous electrical nerve stimulation (TENS) has been used extensively to control postoperative pain, but its effects are controversial. This is probably due to the different types of operations performed and, therefore, to the varying intensity of postoperative pain. Here we present an extensive study with TENS in 324 patients who underwent different types of thoracic surgical procedures: posterolateral thoracotomy, muscle-sparing thoracotomy, costotomy, sternotomy, and video-assisted thoracoscopy. Methods. Each patient cohort was randomly subdivided into three treatment groups: TENS, placebo TENS and control. The effectiveness of TENS was assessed by two factors: the time from the beginning of treatment to the request for further analgesia and the total medication intake during the first 12 hours after operation. Results. Whereas posterolateral thoracotomy produced severe pain, muscle-sparing thoracotomy, costotomy, and sternotomy caused moderate pain, and video-assisted thoracoscopy caused only mild pain. The TENS treatment was not effective in the posterolateral thoracotomy group, but it was useful as an adjunct to other medications in the muscle-sparing thoracotomy, costotomy, and sternotomy groups. In contrast, representing the only pain control treatment with no adjunct drugs, it was very effective in patients having video-assisted thoracoscopy. Conclusions. These findings show that TENS is useful after thoracic surgical procedures only when postoperative pain is mild to moderate; it is uneffective for severe pain.

Functional Improvement After Volume Reduction: Sternotomy Versus Videoendoscopic Approach

Background. Volume reduction has been proved to increase ventilatory mechanics in diffuse, nonbullous lung emphysema. However, the best approach is still controversial. Methods. We retrospectively compared the perioperative data of and functional results in 15 patients having sternotomy (group I) with those of 15 patients having a videoendoscopic approach (group II). Results. The 30-day mortality was 2 patients in group I and 1 patient in group II. Mean duration of chest tube drainage was 8.7 ± 1.8 days and 8.0 ± 1.9 days and mean hospital stay, 12.3 ± 1.9 and 12.5 ± 2.1 days in groups I and II, respectively. Work of breathing decreased from 1.89 ± 0.33 J/L and 1.76 ± 0.22 J/L preoperatively to 0.75 ± 0.06 J/L and 0.8 ± 0.06 J/L ( p < 0.01 and p < 0.05, respectively) after 3 months; and intrinsic positive end-expiratory pressure decreased from 7.15 ± 1.31 cm H 2O and 6.24 ± 1.33 cm H 2O to preoperatively 0.79 ± 0.46 cm H 2O and 1.13 ± 0.44 cm H 2O ( p < 0.005 and p < 0.01, respectively) after 3 months in groups I and II, respectively. Forced expiratory volume in 1 second increased from preoperative values of 21.6% ± 2.9% and 25.3% ± 2.4% of predicted to 34.5% ± 5.0% and 40.9% ± 7.5% of predicted after 3 months ( p < 0.05 in both groups) in groups I and II, respectively. Conclusions. Both surgical approaches resulted in similar substantial improvement in lung function and physical fitness. The incidence of air leakage, the duration of chest tube drainage, and the hospital stay were the same for both procedures.

Sternotomy approach for the modified Blalock-Taussig shunt.

Since 1990, sternotomy has been the preferred approach for construction of a modified Blalock-Taussig shunt (MBTS) at Children's Hospital, Boston, Mass. In retrospect, we sought to test the hypothesis that this approach yields less mortality and morbidity than the traditional thoracotomy approach. One hundred four primary MBTSs with polytetrafluoroethylene grafts were constructed in patients from January 1988 through December 1992. Fifty-two shunts were constructed by thoracotomy approach and 52 by sternotomy approach. Fifteen of the thoracotomy patients were less than one month of age (8 less than 7 days), while 36 of the sternotomy patients were less than 1 month of age (20 less than 7 days). There were 10 shunt failures and 3 hospital deaths in the thoracotomy group and 4 shunt failures with 6 hospital deaths in the sternotomy group. The overall hospital mortality rate for the group was 8.7% (9 of 104). The operative route was not a significant predictor of hospital mortality (P = .30). However, there was a significant difference between the two operative approaches in shunt failure, with shunts that were created by thoracotomy four times more likely to fail than those created by the sternotomy route (odds ratio, OR, 3.88; 95% CI, 1.01 to 15.03; P = .049). The side of the shunt was also a significant predictor of failure with left-side MBTSs foru times more prone to failure (OR, 4.02; 95% CI, 1.19 to 15.25; P = .025). The sternotomy route is technically less challenging and is associated with fewer shunt failures than the classic thoracotomy approach. The potential theoretical disadvantages of this method for future sternal reentry for subsequent procedures was not apparent but requires prospective analysis.

Atrial defibrillation using temporary epicardial defibrillation stainless steel wire electrodes: Studies in the canine sterile pericarditis model

This study sought to determine whether temporary epicardial wire electrodes can be used safely and effectively to defibrillate the atria with low energy shocks in the absence of anesthesia. Atrial fibrillation after open heart surgery is a significant clinical problem. Twelve dogs with sterile pericarditis were studied. In the first group (6 dogs, bilateral thoracotomy group), a wire electrode, insulated except for the distal 6 cm, was placed on the epicardial free wall of each atrium. Each end of the bare wire was then sutured to the parietal pericardium. In the second group (6 dogs, median sternotomy group), the wire electrodes were kept in place by a double loop of Prolene placed around the distal tip of the bare wire and sewn to the overlying parietal pericardium. In the bilateral thoracotomy group, atrial defibrillation thresholds (defined as < 90% and > 10% successful defibrillation of 20 shocks at a given delivered energy) were obtained in anesthetized dogs using the wire electrodes with the chest closed and open and using two transvenously placed catheters with coil electrodes in the distal 6 cm (one in the coronary sinus and the other in the right atrial appendage) with the chest open. In the median sternotomy group, thresholds were obtained in minimally sedated animals without reopening the chest. A 25% increase above threshold shock was also used to determine a new percent success. After 4 days, the wire electrodes were removed by pulling on the external ends. At the time of removal, blood pressure and heart rate were monitored for 30 min, after which dogs were killed and their hearts sent for histopathologic study. For all dogs, chest radiographs were obtained postoperatively and on study days. Atrial defibrillation using the wire electrodes was successful in all dogs at a mean (+/- SE) voltage of 112 +/- 9 V, with an energy level of 0.46 +/- 0.07 J and an impedance of 59.3 +/- 5 ohms. The mean percent success at the atrial defibrillation threshold was 36 +/- 5%. The 25% increase in defibrillation voltage improved the mean percent success to 73% (mean energy 0.66 +/- 0.19 J). No clinical or hemodynamic complications were observed during shock delivery, and no ventricular arrhythmias were induced during the shocks. No complications followed wire electrode removal. Histopathologic analysis showed no structural damage. The atrial defibrillation threshold obtained using temporary epicardial wire electrodes for atrial defibrillation is < 1 J in dogs. Atrial defibrillation using temporary epicardial wire electrodes can be performed safely, quickly and reliably without the need for anesthesia or antiarrhythmic agents. The wire electrodes can be removed without adverse hemodynamic or structural consequences. These data provide a basis for testing atrial defibrillation using epicardial wire electrodes in patients after open heart surgery.

Anterolateral thoracotomy as an alternative to repeat median sternotomy for replacement of the mitral valve

Median sternotomy is the most common approach for repeat cardiac surgery despite the potential complications of cardiac injury. Right anterolateral thoracotomy has been recommended as an alternative for patients undergoing mitral valve replacement, but data supporting one approach over the other do not exist, To compare these procedures, the records of 43 patients who had had a previous median sternotomy and who underwent mitral valve replacement were reviewed. No statistically significant differences between patients undergoing repeat median sternotomy (33 patients) and those undergoing right anterolateral thoracotomy (10 patients) were demonstrable when compared for age, gender, New York Heart Association Functional Class, other diseased valves, urgency of operation, indication for operation, type of valve removed, type of valve implanted, length of post operative hospitalization, length of operation, days of ventilatory support, length of intensive care unit stay, and survival (90% for thoracotomy group; 76% for median sternotomy group; p, NS). Significant differences between the two groups, favoring right anterolateral thoracotomy, were apparent when comparisons were made for length of perfusion (means, 94.8 min, thoracotomy group; 121.4 min, sternotomy group; p = .03), incidence of reexploration (0%, thoracotomy group; 13%, sternotomy group; p = .001), and blood transfusion (means, 5.3 units, thoracotomy group; 11.4 units, sternotomy group; p = .003). Right anterolateral thoracotomy is an effective alternative to repeat median sternotomy for replacement of the mitral valve in patients who have had a previous median sternotomy.

Effects of Thoracotomy on Respiratory System, Lung, and Chest Wall Mechanics

Nineteen rats were sedated, anesthetized, paralyzed, and mechanically ventilated. The respiratory, lung, and chest wall elastances (Est-rs, Est-L, Est-w); respiratory system, pulmonary, and chest wall total resistances (Rtot-rs, Rtot-L, Rtot-w); respiratory system, pulmonary, and chest wall initial resistances (Rinit-rs, Rinit-L, Rinit-w); and respiratory system, pulmonary, and chest wall difference resistances (Rdiff-rs, Rdiff-L, Rdiff-w) were determined before and after thoracotomy using the end-inflation occlusion method. Rinit reflects the Newtonian resistances and Rdiff represents the viscoelastic/inhomogeneous pressure dissipations in the system. Rtot = Rinit+Rdiff, ie, total resistance. The animals were submitted to either anterolateral thoracotomy (group A, n = 7), median sternotomy (group B, n = 6), or median sternotomy under PEEP while the lungs were exposed (group C, n = 6). In groups A and B, statistically significant increases in Rdiff-rs significantly augmented Rtot-rs. The former results were entirely secondary to significant increases in Rdiff-L, which naturally raised Rtot, L. Resistance was not altered in group C rats. Thus, anterolateral thoracotomy and median sternotomy increases Rtot-rs as a consequence of augmented Rdiff-L, but this finding could be prevented by the use of PEEP. Est-rs and Est-L increased in the three groups after surgery. Groups D and E were comprised of four animals each. Both underwent median sternotomy and in group E, PEEP was applied. Histopathologic examination of the lungs demonstrated a higher degree of lung collapse in group D.

Anterolateral Thoracotomy as an Alternative to Repeat Median Sternotomy for Replacement of the Mitral Valve

Median sternotomy is the most common approach for repeat cardiac surgery despite the potential complications of cardiac injury. Right anterolateral thoracotomy has been recommended as an alternative for patients undergoing mitral valve replacement, but data supporting one approach over the other do not exist. To compare these procedures, the records of 43 patients who had had a previous median sternotomy and who underwent mitral valve replacement were reviewed. No statistically significant differences between patients undergoing repeat median sternotomy (33 patients) and those undergoing right anterolateral thoracotomy (10 patients) were demonstrable when compared for age, gender, New York Heart Association Functional Class, other diseased valves, urgency of operation, indication for operation, type of valve removed, type of valve implanted, length of postoperative hospitalization, length of operation, days of ventilatory support, length of intensive care unit stay, and survival (90% for thoracotomy group; 76% for median sternotomy group; p, NS). Significant differences between the two groups, favoring right anterolateral thoracotomy, were apparent when comparisons were made for length of perfusion (means, 94.8 min, thoracotomy group; 121.4 min, sternotomy group; p = .03), incidence of reexploration (0%, thoracotomy group; 13%, sternotomy group; p = .001), and blood transfusion (means, 5.3 units, thoracotomy group; 11.4 units, sternotomy group; p = .003). Right anterolateral thoracotomy is an effective alternative to repeat median sternotomy for replacement of the mitral valve in patients who have had a previous median sternotomy.

Comparison of Median Sternotomy and Thoracotomy for Resection of Pulmonary Metastases in Patients with Adult Soft-Tissue Sarcomas

Thoracotomy and median sternotomy have both been advocated for resection of pulmonary metastases, and the advantages of each approach remain disputed. Patients with adult soft-tissue sarcomas undergoing resection of pulmonary metastases at the National Cancer Institute were studied retrospectively to assess the results of each surgical approach. Between 1981 and 1984, 65 patients underwent 78 sternotomies (7 lobectomies, 71 wedge resections); a mean of 9.5 nodules were resected per patient (range, 1 to 61). Resection of all nodules was accomplished in 60 of 71 explorations (84%) in patients with documented metastases. Benign lesions were found during 7 explorations (9%). Thirteen of 30 patients (43%) with unilateral metastases on linear tomography (LT), 45% (9 of 20) of patients with unilateral metastases on computed tomography (CT), and 38% (5 of 13) of patients with unilateral metastases on both CT and LT had bilateral metastases at sternotomy. Survival by type of incision was compared for 84 patients who underwent complete resection of their metastases (42 by sternotomy and 42 by thoracotomy); the minimum follow-up was two years. The groups did not differ significantly with respect to prognostic variables (tumor doubling time, disease-free interval, or number of nodules resected). There was no significant difference in actuarial survival between the two groups. The complication rate was 15% for the sternotomy group and 10% for the thoracotomy group (difference not significant). There were no operative deaths. Median sternotomy results in detection of unsuspected bilateral metastases and avoidance of a second operative procedure, but it does not increase operative morbidity or mortality or compromise overall patient survival.

Effects of Extracorporeal Circulation upon Blood Lipids

A lipid profile (total lipids, free fatty acids, triglycerides, and serum lipase) and evidence of fatty emboli were studied in patients undergoing cardiopulmonary bypass with median sternotomy or thoracotomy and with or without cardiopulmonary bypass. Although hyperlipemia developed in all patients, there was no statistical difference between the thoracotomy and median sternotomy groups. A marked rise in all four lipid profile factors occurred when both cardiopulmonary bypass and median sternotomy were utilized. Examination of the sputum and urine for evidence of fat and funduscopy for evidence of fat embolization proved to be useless. The postoperative rise in lipid profile factors showed no statistically significant effect on the incidence of neurological or pulmonary complications. A Pall blood filter was used in a second group of patients undergoing cardiopulmonary bypass, but the incidence of neurological or pulmonary complications was similar.