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Improved sternal fixation in bilateral sequential lung transplantation
Cardiothoracic abstracts
Asia Pacific J Thorac Cardiovasc Surg 1994,3(l)
multiple advantages of this incision over a median sternotomy for this operation, one distinct disadvantage is the high incidence of sternal disruption at the stemotomy site which is traditionally closed with sternal wires. This is most likely due to the large force exerted upon a junction of small contact surface area. This disruption rate is as high as 60% in some institutions. It can lead to significant pain and deformity in addition to slowing the postoperative recovery and increasing the risk of sternal infection. To overcome this significant problem we have designed and manufactured a device which provides a sound method of fixating the sternum. There were many problems to overcome when designing such a device. One was the fragility of the sternum with thin outer cortices, making available plating and internal fixation devices inappropriate. The other was the lack of tissue anterior to the sternum and the proximity of the heart posteriorly, limiting device size and shape. The result was a device comprised of 2 plates, one anterior and one posterior to the sternum that were fixed to each other and to the sternum by means of screws into internally threaded posts positioned in pre-drilled holes through the bone on either side of the stemotomy. All components of this device are made from titanium to prevent electrolysis. A range of post lengths and screw lengths are available to accommodate for variability in sternal thickness. This device has been used in 3 patients at our institution after bilateral sequential lung transplantation. Our impression is that the device provides sound sternal fixation and enhances a rapid postoperative recovery. There has been no sternal disruption or infection in any of these patients, with follow-up to 13 weeks. This compares favourably with 4 disruptions out of 11 cases performed with the conventional wiring technique, all of which occurred within 3 weeks postoperatively. We have also used this device successfully in 1 patient suffering chronic pain as a result of sternal disruption from a transverse stemotomy closed with sternal wiring. These preliminary results suggest this is a satisfactory technique for closure of a transverse stemotomy. The results support continued use and further investigation.
The Effect On Blood Flow Of Rotation And Position Of Tbe Internal Mammary Artery Pedicle Robin Brown Alfred Hospital, Melbourne, Victoria, Australia Internal mammary artery (IMA) grafting is routine for most coronary artery bypass procedures throughout the world. The final position of the IMA pedicle will depend upon the target vessel for grafting, the length of the pedicle and the route through or over the pericardium. Prior to anastomosis, the IMA pedicle may be rotated intentionally through 180” for ease of anastomosis or inadvertently through 360” or greater. The aim of this study was to determine the effect of rotation and of different linear deformities of the IMA pedicle upon its blood flow. IMA pedicles were obtained from the autopsy room and stored in normal saline at 4°C until testing within 12 hours. In order to approximate the clinical situation, 26.75% glycerol in normal saline was used as an infusate (as this equals the viscosity of blood at 37°C). This was infused through the arteries at a constant pressure of 100 mmHg and collected in a measuring container over a timed interval in order to determine the flow. The pedicle was then rotated through 180” increments and the process repeated until there was no further flow through the artery. Each of these measurements was made with and without tension in the pedicle for comparison. The determinants of flow were analysed for each increment of rotation with non-parametric regression analysis. It was found that blood flow through the IMA was affected by rotation of the pedicle, and that this occurred after a degree of rotation that was dependant upon the pedicle length. With 360” rotation, flow significantly diminished when the pedicle length was less than 11 cm and ceased altogether with a length of less than 8 cm. With 180” rotation, flow was diminished only once the pedicle length was less than 5 cm. Flow through the artery was found to be inversely proportional to the length of the artery but was not affected by changes in the position of the artery provided there was not a rotational component. Tension of the pedicle did not appear to influence blood flow in either a linear or rotated position. These results have subsequently been verifiod in a clinical settlng. This study would support that a 180” rotation of the IMA pedicle in any clinical setting will not result in any alteration of blood flow. For rotations of 360” or greater, however, the flow may be affected depending on the length of the pedicle, and low diminution becomes significant when pedicle length is less than 12 cm. With regards to the linear position of the artery, this study suggests that flow is not affected by position of the pedicle provided there is not a rotational component. As flow is inversely proportional to length, however, excess pedicle length is best avoided.
Coronary Artery Bypass III Patients With Poor Left Ventricular Function: Reversible vs Irreversible Lschaemia B. Buxton, A. Royse, S. Pomvilawan, J. Raman, B. Sia, J. Horowitz Department of Cardiac Surgery, Austin Hospital Melbourne, Victoria, Australia Myocardial ischaemia may cause reversible myocardial dysfunction (dormant myocardium), nonreversible dysfunction or a combination of both. Hypothesis: That coronary artery bypass grafting (CABG) improves the outcome of patients with poor left ventricular (LV) function. Aim: To study the survival of patients with poor LV function following CABG and to identify any of the commonly used clinical parameters or investigations that predict outcome. Patients and methods: 57 patients with radionuclide
Improved Sternal Fixation In Bilateral Sequential Lung Transplantation Robin Brown, Cohn Lawson Alfred Hospital and Baker Medical Research Institute P&ran, Victoria, Australia The success of bilateral sequential lung transplantation first described in 1990 has led to the rebirth of the trans-sternal bilateral thoracotomy incision. Despite the
43
Asia Pacific J Thorac Cardiovasc Surg 1994,3(l)
multiple advantages of this incision over a median sternotomy for this operation, one distinct disadvantage is the high incidence of sternal disruption at the stemotomy site which is traditionally closed with sternal wires. This is most likely due to the large force exerted upon a junction of small contact surface area. This disruption rate is as high as 60% in some institutions. It can lead to significant pain and deformity in addition to slowing the postoperative recovery and increasing the risk of sternal infection. To overcome this significant problem we have designed and manufactured a device which provides a sound method of fixating the sternum. There were many problems to overcome when designing such a device. One was the fragility of the sternum with thin outer cortices, making available plating and internal fixation devices inappropriate. The other was the lack of tissue anterior to the sternum and the proximity of the heart posteriorly, limiting device size and shape. The result was a device comprised of 2 plates, one anterior and one posterior to the sternum that were fixed to each other and to the sternum by means of screws into internally threaded posts positioned in pre-drilled holes through the bone on either side of the stemotomy. All components of this device are made from titanium to prevent electrolysis. A range of post lengths and screw lengths are available to accommodate for variability in sternal thickness. This device has been used in 3 patients at our institution after bilateral sequential lung transplantation. Our impression is that the device provides sound sternal fixation and enhances a rapid postoperative recovery. There has been no sternal disruption or infection in any of these patients, with follow-up to 13 weeks. This compares favourably with 4 disruptions out of 11 cases performed with the conventional wiring technique, all of which occurred within 3 weeks postoperatively. We have also used this device successfully in 1 patient suffering chronic pain as a result of sternal disruption from a transverse stemotomy closed with sternal wiring. These preliminary results suggest this is a satisfactory technique for closure of a transverse stemotomy. The results support continued use and further investigation.
The Effect On Blood Flow Of Rotation And Position Of Tbe Internal Mammary Artery Pedicle Robin Brown Alfred Hospital, Melbourne, Victoria, Australia Internal mammary artery (IMA) grafting is routine for most coronary artery bypass procedures throughout the world. The final position of the IMA pedicle will depend upon the target vessel for grafting, the length of the pedicle and the route through or over the pericardium. Prior to anastomosis, the IMA pedicle may be rotated intentionally through 180” for ease of anastomosis or inadvertently through 360” or greater. The aim of this study was to determine the effect of rotation and of different linear deformities of the IMA pedicle upon its blood flow. IMA pedicles were obtained from the autopsy room and stored in normal saline at 4°C until testing within 12 hours. In order to approximate the clinical situation, 26.75% glycerol in normal saline was used as an infusate (as this equals the viscosity of blood at 37°C). This was infused through the arteries at a constant pressure of 100 mmHg and collected in a measuring container over a timed interval in order to determine the flow. The pedicle was then rotated through 180” increments and the process repeated until there was no further flow through the artery. Each of these measurements was made with and without tension in the pedicle for comparison. The determinants of flow were analysed for each increment of rotation with non-parametric regression analysis. It was found that blood flow through the IMA was affected by rotation of the pedicle, and that this occurred after a degree of rotation that was dependant upon the pedicle length. With 360” rotation, flow significantly diminished when the pedicle length was less than 11 cm and ceased altogether with a length of less than 8 cm. With 180” rotation, flow was diminished only once the pedicle length was less than 5 cm. Flow through the artery was found to be inversely proportional to the length of the artery but was not affected by changes in the position of the artery provided there was not a rotational component. Tension of the pedicle did not appear to influence blood flow in either a linear or rotated position. These results have subsequently been verifiod in a clinical settlng. This study would support that a 180” rotation of the IMA pedicle in any clinical setting will not result in any alteration of blood flow. For rotations of 360” or greater, however, the flow may be affected depending on the length of the pedicle, and low diminution becomes significant when pedicle length is less than 12 cm. With regards to the linear position of the artery, this study suggests that flow is not affected by position of the pedicle provided there is not a rotational component. As flow is inversely proportional to length, however, excess pedicle length is best avoided.
Coronary Artery Bypass III Patients With Poor Left Ventricular Function: Reversible vs Irreversible Lschaemia B. Buxton, A. Royse, S. Pomvilawan, J. Raman, B. Sia, J. Horowitz Department of Cardiac Surgery, Austin Hospital Melbourne, Victoria, Australia Myocardial ischaemia may cause reversible myocardial dysfunction (dormant myocardium), nonreversible dysfunction or a combination of both. Hypothesis: That coronary artery bypass grafting (CABG) improves the outcome of patients with poor left ventricular (LV) function. Aim: To study the survival of patients with poor LV function following CABG and to identify any of the commonly used clinical parameters or investigations that predict outcome. Patients and methods: 57 patients with radionuclide
Improved Sternal Fixation In Bilateral Sequential Lung Transplantation Robin Brown, Cohn Lawson Alfred Hospital and Baker Medical Research Institute P&ran, Victoria, Australia The success of bilateral sequential lung transplantation first described in 1990 has led to the rebirth of the trans-sternal bilateral thoracotomy incision. Despite the
43