Ann Thorac Surg 2009;87:1304-1306. doi:10.1016/j.athoracsur.2008.08.046
© 2009 The Society of Thoracic Surgeons
How To Do It
Complicated Sternal Dehiscence: Reconstruction With Plates, Cables, and Cannulated Screws
Bernhard Voss, MDa,*,
Robert Bauernschmitt, MDa,
Gernot Brockmann, MDa,
Markus Krane, MDa,
Albrecht Will, MDb,
Rüdiger Lange, MDa
a Department of Cardiovascular Surgery, German Heart Center Munich, Technische Universität München, Munich, Germany
b Department of Radiology, German Heart Center Munich, Technische Universität München, Munich, Germany
Accepted for publication August 18, 2008.
* Address correspondence to Dr Voss, Deutsches Herzzentrum München, Technische Universität München, Lazarettstraße 36, Munich, 80636, Germany (Email: voss{at}dhm.mhn.de).
| Dr Voss discloses that he has a financial relationship with Synthes.
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Abstract
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Sternal dehiscence after median sternotomy can be a challenging problem in case of multiple fractures or infection. For sternal refixation, the principles of rigid plate and screw osteosynthesis gained from orthopedic surgery have been recommended by several authors. We present a new system for sternal reconstruction consisting of reconstruction plates, steel cables, and cannulated screws.
Sternal dehiscence is the most common complication after median sternotomy with an incidence of 0.5% to 5.0%, especially in patients with obesity, osteoporosis, diabetes, or chronic obstructive pulmonary disease [1]. In cases in which complicated sternal reconstruction is required because of multiple fractures, the principles of rigid plate and screw osteosynthesis gained from cranio-maxillofacial and orthopedic surgery have been recommended by several authors [2–4]. We present the closure technique for dehiscent sternum with a new sternal closure system (Modular Synthes Sternal Cable System; Synthes GmbH, Oberdorf, Switzerland) consisting of reconstruction plates, steel cables, and cannulated screws.
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Technique
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The Modular Synthes Sternal Cable System (Synthes GmbH) is a set of stainless steel implants consisting of:- 1 Sternal reconstruction plates (3-mm thickness, 8-mm wide) with a length from 80 mm to 192 mm (16-mm increments) and 10 to 24 screw holes (Ø 4.6 mm). Additional small transverse holes (Ø 1.2 mm) for peristernal cable passage are drilled between the screw holes.
- 2 Cannulated sternal screws (Ø 4.5 mm), self-tapping with a length from 8.0 mm to 24 mm (1-mm increments).
- 3 Multifilament sternal cables (Ø 1.0 mm) with a length 750 mm. A clamping sleeve makes it possible to hook in the end of the cable into a cannulated sternal screw. The free cable end can be fixed by ferrule crimping after passing through a transverse plate hole.
The operation is performed under general anesthesia. First, the sternum is dissected free from surrounding tissue. The degree of sternal separation, bone vitality, and the presence of fractures and infection is assessed. In case of infection, the sternal wound is treated first by systematic debridement, vacuum-assisted closure device, and antibiotic therapy until it is germ-free. For reconstruction, two sternal plates are fitted individually, according to the anatomical shape of the sternal halves in a longitudinal fashion. The use of bending pliers is helpful to fit the plates perfectly to the sternal surface. Every plate is fixed with 5 to 10 cannulated screws, which are placed in solid osseous areas. If necessary, a 2.7-mm awl can be used to create pilot holes in the body of the sternum. The self-tapping, cannulated screws are inserted with an adjustable screwdriver with spade point. A depth gauge is used to select the appropriate screw length. Bi-cortical screw insertion is necessary for maximum effectiveness. After approximating the sternal halves with reduction forceps or some sternal cerclages, the sternum is finally closed with transverse cables, which are guided with a cable passer through the cannulated screws and the transverse holes of the plates. The cables are tensioned, crimped, and cut in one step with a special device.
Illustrative Case Report
A 75-year-old obese patient (103 kg; body mass index, 34) with insulin-dependent diabetes mellitus, hypercholesterolemia, and nicotine abuse (50 pack-years) underwent quadruple coronary artery bypass surgery. After an uneventful postoperative course the patient was discharged on postoperative day 7 in good condition with a stable sternum. Three weeks after surgery, the patient was readmitted with pain due to a purulent instable and multiple fractured sternum. The infection (coagulase-negative staphylococci) was treated by inserting a vacuum-assisted closure device and multiple pulsed-jet lavages. According to the bacterial sensitivity, the patient was treated with intravenous application of vancomycin. After 10 days the wound was germ free. Considering the patient's risk factors, we applied the new closure system (Fig 1) to prevent future sternal instability. The operation time was 110 minutes and the patient was extubated 1 hour postoperatively. The postoperative roentgenogram showed good positioning of the plates (Fig 2). On postoperative day 5, the patient was discharged from the hospital.
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Fig 1. (A) Sternal space after debridement and 10 days of vacuum-assisted closure device therapy. Transverse fractures are seen on both sternal halves. (B) Longitudinal sternal reinforcement: the cables are still loosely passed through the cannulated screws and the plate's transverse holes. (C) First, the sternum is reduced by three steel wires, and second they are fixed by tensioning and crimping the seven cables.
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Comment
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In general, sternal nonunion can successfully be treated by simple rewiring or technical modification of rewiring as described by Robicsek and colleagues [5]. However, in cases of poor bone quality or multiple transverse sternal fractures, or when the inability to reduce risk factors results in instability, steel wires, or bands, which sometimes fail to prevent excessive motion leading to insufficient bone healing. If a reunion by rewiring has failed, muscle flaps or mesh grafts can also be used to close the sternal defect. However, in the long term, many patients complain of chronic pain resulting from the sternal separation [6]. Therefore, solid thoracic fixation is preferable. It is generally accepted that limiting relative motion between broken segments of bone is beneficial for rapid bony healing [7]. Recent in vitro and animal studies comparing the stability of rigid plate fixation versus wire fixation proved the significant superiority of rigid plates [8]. Despite these findings, the clinical use of plates for sternal reconstruction is still rare. However, only longitudinal plating allows immediate stabilization of multiple fractured sternal bone fragments in the horizontal, as well as in the vertical plane. In contrast to the new system presented here, so far, longitudinal plated sternal halves have been approximated by wiring or plate cross connections, or both [3, 4], technically different from our technique. The new Modular Synthes Sternal Cable System (Synthes GmbH) optimizes sternal closure after longitudinal plating by using flexible cables that fit perfectly to the shape of the sternum. Thereby, the force between fragments is increased, allowing for faster callus formation. In combination with cannulated screws as metal cannula for cable passage, the sternal bone is particularly reinforced, thus minimizing the risk of sternal cutting. In summary, the Modular Synthes Sternal Cable System provides an excellent distribution of forces along the length of the sternum. Therefore, it is a useful tool to treat patients with sternal dehiscence, especially in complicated cases.
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References
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- Robicsek F, Daugherty HK, Cook JW. The prevention and treatment of sternum separation following open-heart surgery J Thorac Cardiovasc Surg 1977;73:267-268.[Abstract]
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- Pai S, Gunja NJ, Dupak EL, et al. In vitro comparison of wire and plate fixation for midline sternotomies Ann Thorac Surg 2005;80:962-968.[Abstract/Free Full Text]
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Abstract
Introduction
