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Transverse Plate Fixation of Sternum: A New Sternal-Sparing Technique
1016
CASE REPORT LÓPEZ ALMODÓVAR ET AL TRANSVERSE PLATE FIXATION OF THE STERNUM
Transverse Plate Fixation of Sternum: A New Sternal-Sparing Technique Luis F. López Almodóvar, MD, Gema Bustos, MD, Pedro Lima, MD, Alfonso Cañas, MD, Isidro Paredes, MD, and José A. Buendía, MD Departments of Cardiac Surgery, Plastic Surgery, and Cardiac Anesthesia, Virgen de la Salud Hospital, Toledo, Spain
We report 2 cases of vacuum-assisted closure therapy and thoracic reconstruction using new sternum titatium plates in patients with deep sternal wound infection after median sternotomy. The specific advantage of this new approach is anatomical reduction of the sternum that prevents paradoxical movement and severe anterior chest instability, and improves postoperative outcome. (Ann Thorac Surg 2008;86:1016 –7) © 2008 by The Society of Thoracic Surgeons
D
FEATURE ARTICLES
eep sternal wound infection is a complication after median sternotomy, with high morbidity and mortality despite advances in antibiotic therapy and wound healing strategies. The classic approach includes aggressive debridement and pectoral muscle flaps or omentum transposition; however, this may lead to thoracic instability necessitating prolonged ventilatory support, extended hospital stay, and increased costs. Some authors [1, 2] have reported promising results with complex wound healing using the vacuum-assisted closure (VAC) technique. The principle of this technique is based on uniform negative pressure applied to the wound, resulting in arteriolar dilatation and thus promoting granulation tissue proliferation. Recently, a new technique that restores the sternal integrity after complications of median sternotomy was described [3–5]. The new rigid sternal fixation system (Synthes GmbH, Solothurn, Switzerland) consists of titanium unilock screws and 2.4 mm thickness titanium plates available in various lengths. Sternal reconstruction should support the chest wall and provide normal respiratory mechanics. We report 2 cases in which this new sternal fixation system was used.
Ann Thorac Surg 2008;86:1016 –7
attention to the left hemisternum and underlying right ventricle, followed by irrigation with saline solution. Because the pericardium was not closed, a surgical towel was placed at the bottom of the wound, covering and isolating visible parts of the right ventricle and grafts. Two VAC sponges (KCI Inc, San Antonio, TX) were cut and fitted into the sternal wound and connected with a Y piece, with continuous suction of 100 to 125 mm Hg. According to the algorithm for VAC therapy in poststernotomy mediastinitis proposed by Sjögren et al [6], VAC therapy was changed in the operating room every three days. When bacteriological cultures were negative and C-reactive protein level was less than 70 mg/L, after 9 days, the VAC therapy was removed and patients underwent thoracic reconstruction with the new system. After debridement of devitalized bone, the ribs were exposed laterally to the midline of the clavicle by dissection of the major pectoral muscle and the overlying soft tissue from the medial with electrocautery. The accurate length of the screws was determined by measuring with a depth gauge from the sternal edges. The sternum was reduced, maintaining it in position with rib approximators. A minimun of 3 ribs were selected for plate placement. In 1 patient, a star-shaped manubrium plate was needed for reinforcement. A malleable template may be used beforehand to best fit the plates transversely across each paired
As soon as deep sternal wound infection was diagnosed clinically, the patients were taken to the operating room and their wounds were explored. Foreign material such as steel wires and sutures was removed by means of debridment. Five tissue cultures obtained from various wound sites demonstrated Staphylococcus epidermidis in both patients. Antibiotic therapy was initiated. Debridement of necrotic tissue was performed, and sternal edges were revised with special Accepted for publication Feb 18, 2008. Address correspondence to Dr López Almodóvar, Department of Cardiac Surgery, Virgen de la Salud Hospital, Avda. Barber 30, Toledo, 45005, Spain; e-mail: [email protected].
© 2008 by The Society of Thoracic Surgeons Published by Elsevier Inc
Fig 1. Locked reconstruction with plates restoring sternal integrity. 0003-4975/08/$34.00 doi:10.1016/j.athoracsur.2008.02.046
rib. The plates are positioned across the 2 sternal halves. The emergency release pin should be parallel to the midline of the sternum and cranially oriented. Its length must be adequate to enable placement of a minimum of 3 screws in each rib and another screw in each hemisternum. A corresponding reconstruction plate is cut and contoured to fit the template. With the plate positioned toward the superior edge of the rib, the risk of injury to intercostal nerves and vessels during drilling of holes is averted. A threaded drill guide included with the system is screwed into the chosen plate hole. A 1.8-mm drill bit of a length chosen to prevent inadvertent pleural penetration is used to make bicortical holes in the hemisternum and monocortical or bicortical holes just posterior to the perichondrium of the rib. If there is any doubt about the ribs, the screws should be placed monocortically. Drilling of holes just in the lateral border of the sternum, which correspond to the location of the internal mammary vessels, must be prevented. Then 3.0-mm sternal unilock screws of the desired lengths are inserted through the plate and tightened until secure (Fig 1). The pectoralis muscles are then sewn to each other in the midline with resorbable suture material to provide complete coverage of all exposed bone, cartilage, and plates. A drainage tube is inserted under each pectoral muscle flap to reduce the risk of seroma formation. The remainder of the wound is closed in the usual manner. In both of our patients, the postoperative course was uneventful, and at 5-month follow-up the sternum was stable.
Comment Deep sternal wound infection is a most feared complication in patients undergoing cardiac surgery. In many cases, because of sternum instability or infection, complete debridement of the sternum and concomitant pectoral muscle flap reconstruction is performed, which procedure is associated with high morbidity and mortality, thoracic instability, and increased costs. The VAC system used as a bridge between debridement and reconstruction has some advantages, such as decrease in the number of complications and shorter hospital stay. However, in many cases after VAC therapy, rewiring of the sternum is considered inadvisable if the bone is osteoporotic or has sustained fractures where the original wires have pulled through. If complete resection of the sternum is required, reconstruction can become problematic because muscle flaps may not prevent paradoxical chest wall movement, and thoracic instability may occur necessitating prolonged ventilatory support, which increases the risk of complications such a pneumonia, thrombosis, and muscle weakening. The transverse plate fixation system is a new sternalsparing technique for treatment of these complications. In patients with multiple transverse sternal fractures, the plates can be placed over the fractured parts and with unilock screws stability of the sternum can be
CASE REPORT LÓPEZ ALMODÓVAR ET AL TRANSVERSE PLATE FIXATION OF THE STERNUM
1017
Fig 2. Chest x-ray film demostrates sternal union.
achieved. Preservation of the sternum, although fractured, results in improved ventilation and reduced pain after surgery. Some caveats must be mentioned. Drilling too deep or using screws that are too long increase the risk of penumothorax; therefore a routine postoperative chest x-ray study is mandatory (Fig 2). The presence of infection is a relative contraindication to use of any system of plate fixation; however, VAC therapy may eradicate the relevant bacterium in 48 to 72 hours. Use of this new system of plate fixation must be individualized for each patient. The technique is safe and easy to implement, but long-term follow up in more patients is needed to evaluate associated risks.
References 1. Fleck TM, Fleck M, Moidl R, et al. The vacuum-assisted closure system for the treatment of deep sternal wound infections after cardiac surgery. Ann Thorac Surg 2002;74: 1596 –1600. 2. Gustafsson RI, Sjögren J, Ingemansson R. Deep sternal wound infection: a sternal-sparing technique with vacuumassisted closure therapy. Ann Thorac Surg 2003;76:2048 –53. 3. Cicilioni OJ, Stieg FK, Papanicolau G. Sternal wound reconstruction with transverse plate fixation. Plast Reconstr Surg 2005;115:1297–1303. 4. Plass A, Grünenfelder J, Reuthebuch O, et al. New transverse plate fixation system for complicated sternal wound infection after median sternotomy. Ann Thorac Surg 2007;83:1210 –2. 5. Hallock GG, Szydlowski GW. Rigid fixation of the sternum using a new coupled titanium transverse plate fixation system. Ann Plast Surg 2007;58:640 – 4. 6. Sjögren J, Malmsjö M, Gustafsson R, Ingemansson R. Postesternotomy mediastinitis: a review of conventional surgical treatments, vacuum-assisted closure therapy and presentation of the Lund University Hospital mediastinitis algorithm. Eur J Cardiothorac Surg 2006;30:898 –905.
FEATURE ARTICLES
Ann Thorac Surg 2008;86:1016 –7
CASE REPORT LÓPEZ ALMODÓVAR ET AL TRANSVERSE PLATE FIXATION OF THE STERNUM
Transverse Plate Fixation of Sternum: A New Sternal-Sparing Technique Luis F. López Almodóvar, MD, Gema Bustos, MD, Pedro Lima, MD, Alfonso Cañas, MD, Isidro Paredes, MD, and José A. Buendía, MD Departments of Cardiac Surgery, Plastic Surgery, and Cardiac Anesthesia, Virgen de la Salud Hospital, Toledo, Spain
We report 2 cases of vacuum-assisted closure therapy and thoracic reconstruction using new sternum titatium plates in patients with deep sternal wound infection after median sternotomy. The specific advantage of this new approach is anatomical reduction of the sternum that prevents paradoxical movement and severe anterior chest instability, and improves postoperative outcome. (Ann Thorac Surg 2008;86:1016 –7) © 2008 by The Society of Thoracic Surgeons
D
FEATURE ARTICLES
eep sternal wound infection is a complication after median sternotomy, with high morbidity and mortality despite advances in antibiotic therapy and wound healing strategies. The classic approach includes aggressive debridement and pectoral muscle flaps or omentum transposition; however, this may lead to thoracic instability necessitating prolonged ventilatory support, extended hospital stay, and increased costs. Some authors [1, 2] have reported promising results with complex wound healing using the vacuum-assisted closure (VAC) technique. The principle of this technique is based on uniform negative pressure applied to the wound, resulting in arteriolar dilatation and thus promoting granulation tissue proliferation. Recently, a new technique that restores the sternal integrity after complications of median sternotomy was described [3–5]. The new rigid sternal fixation system (Synthes GmbH, Solothurn, Switzerland) consists of titanium unilock screws and 2.4 mm thickness titanium plates available in various lengths. Sternal reconstruction should support the chest wall and provide normal respiratory mechanics. We report 2 cases in which this new sternal fixation system was used.
Ann Thorac Surg 2008;86:1016 –7
attention to the left hemisternum and underlying right ventricle, followed by irrigation with saline solution. Because the pericardium was not closed, a surgical towel was placed at the bottom of the wound, covering and isolating visible parts of the right ventricle and grafts. Two VAC sponges (KCI Inc, San Antonio, TX) were cut and fitted into the sternal wound and connected with a Y piece, with continuous suction of 100 to 125 mm Hg. According to the algorithm for VAC therapy in poststernotomy mediastinitis proposed by Sjögren et al [6], VAC therapy was changed in the operating room every three days. When bacteriological cultures were negative and C-reactive protein level was less than 70 mg/L, after 9 days, the VAC therapy was removed and patients underwent thoracic reconstruction with the new system. After debridement of devitalized bone, the ribs were exposed laterally to the midline of the clavicle by dissection of the major pectoral muscle and the overlying soft tissue from the medial with electrocautery. The accurate length of the screws was determined by measuring with a depth gauge from the sternal edges. The sternum was reduced, maintaining it in position with rib approximators. A minimun of 3 ribs were selected for plate placement. In 1 patient, a star-shaped manubrium plate was needed for reinforcement. A malleable template may be used beforehand to best fit the plates transversely across each paired
As soon as deep sternal wound infection was diagnosed clinically, the patients were taken to the operating room and their wounds were explored. Foreign material such as steel wires and sutures was removed by means of debridment. Five tissue cultures obtained from various wound sites demonstrated Staphylococcus epidermidis in both patients. Antibiotic therapy was initiated. Debridement of necrotic tissue was performed, and sternal edges were revised with special Accepted for publication Feb 18, 2008. Address correspondence to Dr López Almodóvar, Department of Cardiac Surgery, Virgen de la Salud Hospital, Avda. Barber 30, Toledo, 45005, Spain; e-mail: [email protected].
© 2008 by The Society of Thoracic Surgeons Published by Elsevier Inc
Fig 1. Locked reconstruction with plates restoring sternal integrity. 0003-4975/08/$34.00 doi:10.1016/j.athoracsur.2008.02.046
rib. The plates are positioned across the 2 sternal halves. The emergency release pin should be parallel to the midline of the sternum and cranially oriented. Its length must be adequate to enable placement of a minimum of 3 screws in each rib and another screw in each hemisternum. A corresponding reconstruction plate is cut and contoured to fit the template. With the plate positioned toward the superior edge of the rib, the risk of injury to intercostal nerves and vessels during drilling of holes is averted. A threaded drill guide included with the system is screwed into the chosen plate hole. A 1.8-mm drill bit of a length chosen to prevent inadvertent pleural penetration is used to make bicortical holes in the hemisternum and monocortical or bicortical holes just posterior to the perichondrium of the rib. If there is any doubt about the ribs, the screws should be placed monocortically. Drilling of holes just in the lateral border of the sternum, which correspond to the location of the internal mammary vessels, must be prevented. Then 3.0-mm sternal unilock screws of the desired lengths are inserted through the plate and tightened until secure (Fig 1). The pectoralis muscles are then sewn to each other in the midline with resorbable suture material to provide complete coverage of all exposed bone, cartilage, and plates. A drainage tube is inserted under each pectoral muscle flap to reduce the risk of seroma formation. The remainder of the wound is closed in the usual manner. In both of our patients, the postoperative course was uneventful, and at 5-month follow-up the sternum was stable.
Comment Deep sternal wound infection is a most feared complication in patients undergoing cardiac surgery. In many cases, because of sternum instability or infection, complete debridement of the sternum and concomitant pectoral muscle flap reconstruction is performed, which procedure is associated with high morbidity and mortality, thoracic instability, and increased costs. The VAC system used as a bridge between debridement and reconstruction has some advantages, such as decrease in the number of complications and shorter hospital stay. However, in many cases after VAC therapy, rewiring of the sternum is considered inadvisable if the bone is osteoporotic or has sustained fractures where the original wires have pulled through. If complete resection of the sternum is required, reconstruction can become problematic because muscle flaps may not prevent paradoxical chest wall movement, and thoracic instability may occur necessitating prolonged ventilatory support, which increases the risk of complications such a pneumonia, thrombosis, and muscle weakening. The transverse plate fixation system is a new sternalsparing technique for treatment of these complications. In patients with multiple transverse sternal fractures, the plates can be placed over the fractured parts and with unilock screws stability of the sternum can be
CASE REPORT LÓPEZ ALMODÓVAR ET AL TRANSVERSE PLATE FIXATION OF THE STERNUM
1017
Fig 2. Chest x-ray film demostrates sternal union.
achieved. Preservation of the sternum, although fractured, results in improved ventilation and reduced pain after surgery. Some caveats must be mentioned. Drilling too deep or using screws that are too long increase the risk of penumothorax; therefore a routine postoperative chest x-ray study is mandatory (Fig 2). The presence of infection is a relative contraindication to use of any system of plate fixation; however, VAC therapy may eradicate the relevant bacterium in 48 to 72 hours. Use of this new system of plate fixation must be individualized for each patient. The technique is safe and easy to implement, but long-term follow up in more patients is needed to evaluate associated risks.
References 1. Fleck TM, Fleck M, Moidl R, et al. The vacuum-assisted closure system for the treatment of deep sternal wound infections after cardiac surgery. Ann Thorac Surg 2002;74: 1596 –1600. 2. Gustafsson RI, Sjögren J, Ingemansson R. Deep sternal wound infection: a sternal-sparing technique with vacuumassisted closure therapy. Ann Thorac Surg 2003;76:2048 –53. 3. Cicilioni OJ, Stieg FK, Papanicolau G. Sternal wound reconstruction with transverse plate fixation. Plast Reconstr Surg 2005;115:1297–1303. 4. Plass A, Grünenfelder J, Reuthebuch O, et al. New transverse plate fixation system for complicated sternal wound infection after median sternotomy. Ann Thorac Surg 2007;83:1210 –2. 5. Hallock GG, Szydlowski GW. Rigid fixation of the sternum using a new coupled titanium transverse plate fixation system. Ann Plast Surg 2007;58:640 – 4. 6. Sjögren J, Malmsjö M, Gustafsson R, Ingemansson R. Postesternotomy mediastinitis: a review of conventional surgical treatments, vacuum-assisted closure therapy and presentation of the Lund University Hospital mediastinitis algorithm. Eur J Cardiothorac Surg 2006;30:898 –905.
FEATURE ARTICLES
Ann Thorac Surg 2008;86:1016 –7