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Sternal non-union—development of a novel fixation device
Injury Extra (2005) 36, 569—572
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CASE REPORT
Sternal non-union–—development of a novel fixation device Arndt P. Schulz *, Maximilian Faschingbauer, Christian Ju ¨rgens Department of Trauma and Orthopaedic Surgery, BG Trauma Hospital Hamburg, Bergedorfer Strasse 10, 21033 Hamburg Germany Accepted 16 May 2005
Introduction Fractures of the sternum are often related to highspeed trauma. In these cases the injuries related to the fracture tend to cause the problems in acute trauma management. If there is no gross displacement, sternal fractures can be safely managed on a conservative basis with good results.3,5 Once unstable non-union occurs, it is a very disabling condition and requires treatment. The often attempted method of osteosynthesis is tension-wiring. Due to loosening of tensile strength or wire cutout, this method frequently fails. Several methods have been tried to overcome this problem. These included plating of the sternum to give the tension wires more hold,4 combining the wires with anchor plates to increase the tensile strength6 and even intramedullary plating.2 Plate osteosynthesis with two or more parallel plates has been reported1,4 with unsatisfactory results. We present a case of a 28-year-old very active male whose occupation includes constant heavy lifting. Wiring of the sternum was thought to be a high risk of material failure and we developed an implant for this case. It is based on the principle of * Corresponding author. Tel.: +49 40 73060; fax: +49 40 73062406. E-mail address: [email protected] (A.P. Schulz).
an internal plate fixator. This device achieves multidirectional stability.
Case report In this case of a 28-year-old stone mason had a severe motorbike RTA in which he sustained multiple injuries including a shearing fracture of the upper lumbar spine and a transverse sternal fracture, no rib fractures but fractures of unilateral transverse processes of Th12-L5. Treatment of the sternal fracture was conservative, spinal stabilisation was performed with an internal plate fixator, the patient was free of neurological symptoms at discharge. Six months after initial treatment sternal non-union was diagnosed. The patient complained of frequent painful luxation events of the proximal fragment behind the distal. This occurred especially when associated with lifting heavy objects or bending forward and backwards. A return to work was impossible due to this condition (Fig. 1). For this problem we developed a new implant after CT-measurement of the sternum (Figs. 2 and 3). It is an 8-hole titanium plate, the fixation of the screws is based on the principles of angular stable fixation, the screw-heads lock in the plate. The
1572-3461/$ — see front matter # 2005 Elsevier Ltd. All rights reserved. doi:10.1016/j.injury.2005.05.043
570
A.P. Schulz et al.
Figure 1
Luxation of the sternal fragments.
Figure 2 and 3
Figure 4
screws are standard angular stable cortical screws but had to be shortened to facilitate this specific purpose. The holes are in two rows with different angles of direction. By this the multidirectional forces that occur at the sternum can be counterbalanced. The implant was made to our specification by a medical device manufacturer (Litos GmbH, Hamburg, Germany). The overall thickness is 5mm; the screw heads are even with the plate once tightened. The material is pure titanium (Fig. 4). The locking mechanism is gained by a construction developed by Wolter.7 The plate itself has not a thread but a lip. By inserting a screw with an extra thread in the head, the screw threads itself into the plate at an angle determined by the surgeon and locks in this position. This is possible because plate
Planning of implant after CT measurement.
Implant, low contact area visible in the middle, Screws on right picture not locked yet.
Sternal non-union–—development of a novel fixation device
Figure 5
571
Locking mechanism of screw head in the plate. Figure 9
Figure 6
Intraoperative view of non-union, plate in situ.
and screw are made of titanium of different hardness-grade (Fig. 5). After a longitudinal 8 cm incision over the nonunion, fibrous tissue was removed and cancellous bone grafting was performed. By overextension of the chest, reposition was possible with gentle compression on the distal fragment (Fig. 6).
Figure 7 and 8
Three months postoperatively.
The only slight intraoperative problem was the length of the screws. As these had been made from shortened 3.5 mm cortical screws in only a specified amount of each length, it showed the uppermost screws approximately one millimetre to long, we thought this as acceptable (Figs. 7 and 8). The postoperative course was uneventful; a light corset was prescribed, more as a reminder to this active young man. Heavy lifting and riding his motorbike was forbidden for 3 months. Postoperative X-rays showed good adaptation of the fragments. At 3 months follow-up, the patient was free of symptoms. The material was hardly palpable and did not cause him any symptoms. He had worn his corset ‘‘most of the time’’ and had ridden his racing motorbike ‘‘only a few times’’ although he attended the clinic with a crash helmet (Fig. 9). He was allowed to return to work, with no indication to restrict social activities. We have decided for a planned removal of metalwork after 12 months. We have since used this new implant once, in a case
Intraoperative fluoroscopy.
572
of a sternal fracture with gross displacement, also with a good result.
Discussion Due to multidirectional movements with tension and compression acting in all planes, fracture and pseuarthrosis-fixation on the sternum remains challenging. In the case of a longitudinal osteotomy tension wires most often keep their strength long enough to achieve union. In horizontal sternal fractures and non-unions tension wires often fail. In theses situations a multidirectionally stable fixation device as the internal titanium-fixator can overcome the problems that occur in this specific location. At the moment we try to develop an implant of less thickness, biomechanical testing will have to show if this can then give enough stability at this location.
A.P. Schulz et al.
References 1. Bertin KC, Rice RS, Doty DB, Jones KW. Repair of transverse sternal non-union using metal plates and autogenous bone graft. Ann Thorac Surg 2002;73:1661—2. 2. Hoofwijk AGM, Lobach HJC, Chr. van der Werken. Intramedullary fixation of fracture of the sternum. Injury 1988;19(March (2)):128—9. 3. Potaris K, Gakidis J, Mihos P, et al. Management of sternal fractures: 239 cases. Asian Cardiovasc Thorac Ann 2002;10 (June (2)):145—9. 4. Smoot EC, Weimann D, Paramedian Sternal Bone Plate Reinforcement and Wiring for difficult sternotomy. Ann Plastic Surg;14(5):465—7. 5. Velissaris T, Tang AT, Patel A, Khallifa K, Weeden DF. Traumatic sternal fracture: outcome following admission to a Thoracic Surgical Unit. Injury 2003;34(December (12)):924—7. 6. Vincent JG, Update on sternal osteosynthesis. Ann Thorac Surg;41:216—8. 7. Wolter D, Schu ¨mann U, Seide K. Universal Titanium Internal Fixator. Trauma Berufskrankh 1999;1:307—19.
www.elsevier.com/locate/inext
CASE REPORT
Sternal non-union–—development of a novel fixation device Arndt P. Schulz *, Maximilian Faschingbauer, Christian Ju ¨rgens Department of Trauma and Orthopaedic Surgery, BG Trauma Hospital Hamburg, Bergedorfer Strasse 10, 21033 Hamburg Germany Accepted 16 May 2005
Introduction Fractures of the sternum are often related to highspeed trauma. In these cases the injuries related to the fracture tend to cause the problems in acute trauma management. If there is no gross displacement, sternal fractures can be safely managed on a conservative basis with good results.3,5 Once unstable non-union occurs, it is a very disabling condition and requires treatment. The often attempted method of osteosynthesis is tension-wiring. Due to loosening of tensile strength or wire cutout, this method frequently fails. Several methods have been tried to overcome this problem. These included plating of the sternum to give the tension wires more hold,4 combining the wires with anchor plates to increase the tensile strength6 and even intramedullary plating.2 Plate osteosynthesis with two or more parallel plates has been reported1,4 with unsatisfactory results. We present a case of a 28-year-old very active male whose occupation includes constant heavy lifting. Wiring of the sternum was thought to be a high risk of material failure and we developed an implant for this case. It is based on the principle of * Corresponding author. Tel.: +49 40 73060; fax: +49 40 73062406. E-mail address: [email protected] (A.P. Schulz).
an internal plate fixator. This device achieves multidirectional stability.
Case report In this case of a 28-year-old stone mason had a severe motorbike RTA in which he sustained multiple injuries including a shearing fracture of the upper lumbar spine and a transverse sternal fracture, no rib fractures but fractures of unilateral transverse processes of Th12-L5. Treatment of the sternal fracture was conservative, spinal stabilisation was performed with an internal plate fixator, the patient was free of neurological symptoms at discharge. Six months after initial treatment sternal non-union was diagnosed. The patient complained of frequent painful luxation events of the proximal fragment behind the distal. This occurred especially when associated with lifting heavy objects or bending forward and backwards. A return to work was impossible due to this condition (Fig. 1). For this problem we developed a new implant after CT-measurement of the sternum (Figs. 2 and 3). It is an 8-hole titanium plate, the fixation of the screws is based on the principles of angular stable fixation, the screw-heads lock in the plate. The
1572-3461/$ — see front matter # 2005 Elsevier Ltd. All rights reserved. doi:10.1016/j.injury.2005.05.043
570
A.P. Schulz et al.
Figure 1
Luxation of the sternal fragments.
Figure 2 and 3
Figure 4
screws are standard angular stable cortical screws but had to be shortened to facilitate this specific purpose. The holes are in two rows with different angles of direction. By this the multidirectional forces that occur at the sternum can be counterbalanced. The implant was made to our specification by a medical device manufacturer (Litos GmbH, Hamburg, Germany). The overall thickness is 5mm; the screw heads are even with the plate once tightened. The material is pure titanium (Fig. 4). The locking mechanism is gained by a construction developed by Wolter.7 The plate itself has not a thread but a lip. By inserting a screw with an extra thread in the head, the screw threads itself into the plate at an angle determined by the surgeon and locks in this position. This is possible because plate
Planning of implant after CT measurement.
Implant, low contact area visible in the middle, Screws on right picture not locked yet.
Sternal non-union–—development of a novel fixation device
Figure 5
571
Locking mechanism of screw head in the plate. Figure 9
Figure 6
Intraoperative view of non-union, plate in situ.
and screw are made of titanium of different hardness-grade (Fig. 5). After a longitudinal 8 cm incision over the nonunion, fibrous tissue was removed and cancellous bone grafting was performed. By overextension of the chest, reposition was possible with gentle compression on the distal fragment (Fig. 6).
Figure 7 and 8
Three months postoperatively.
The only slight intraoperative problem was the length of the screws. As these had been made from shortened 3.5 mm cortical screws in only a specified amount of each length, it showed the uppermost screws approximately one millimetre to long, we thought this as acceptable (Figs. 7 and 8). The postoperative course was uneventful; a light corset was prescribed, more as a reminder to this active young man. Heavy lifting and riding his motorbike was forbidden for 3 months. Postoperative X-rays showed good adaptation of the fragments. At 3 months follow-up, the patient was free of symptoms. The material was hardly palpable and did not cause him any symptoms. He had worn his corset ‘‘most of the time’’ and had ridden his racing motorbike ‘‘only a few times’’ although he attended the clinic with a crash helmet (Fig. 9). He was allowed to return to work, with no indication to restrict social activities. We have decided for a planned removal of metalwork after 12 months. We have since used this new implant once, in a case
Intraoperative fluoroscopy.
572
of a sternal fracture with gross displacement, also with a good result.
Discussion Due to multidirectional movements with tension and compression acting in all planes, fracture and pseuarthrosis-fixation on the sternum remains challenging. In the case of a longitudinal osteotomy tension wires most often keep their strength long enough to achieve union. In horizontal sternal fractures and non-unions tension wires often fail. In theses situations a multidirectionally stable fixation device as the internal titanium-fixator can overcome the problems that occur in this specific location. At the moment we try to develop an implant of less thickness, biomechanical testing will have to show if this can then give enough stability at this location.
A.P. Schulz et al.
References 1. Bertin KC, Rice RS, Doty DB, Jones KW. Repair of transverse sternal non-union using metal plates and autogenous bone graft. Ann Thorac Surg 2002;73:1661—2. 2. Hoofwijk AGM, Lobach HJC, Chr. van der Werken. Intramedullary fixation of fracture of the sternum. Injury 1988;19(March (2)):128—9. 3. Potaris K, Gakidis J, Mihos P, et al. Management of sternal fractures: 239 cases. Asian Cardiovasc Thorac Ann 2002;10 (June (2)):145—9. 4. Smoot EC, Weimann D, Paramedian Sternal Bone Plate Reinforcement and Wiring for difficult sternotomy. Ann Plastic Surg;14(5):465—7. 5. Velissaris T, Tang AT, Patel A, Khallifa K, Weeden DF. Traumatic sternal fracture: outcome following admission to a Thoracic Surgical Unit. Injury 2003;34(December (12)):924—7. 6. Vincent JG, Update on sternal osteosynthesis. Ann Thorac Surg;41:216—8. 7. Wolter D, Schu ¨mann U, Seide K. Universal Titanium Internal Fixator. Trauma Berufskrankh 1999;1:307—19.