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Computerised navigation for closed reduction during femoral intramedullary nailing
Injury, Int. J. Care Injured (2005) 36, 866—870
www.elsevier.com/locate/injury
CASE REPORT
Computerised navigation for closed reduction during femoral intramedullary nailing Rami Mosheiff a,*, Yoram Weil a, Eran Peleg b, Meir Liebergall a a
Department of Orthopaedic Surgery, The Hadassah-Hebrew University Medical School, P.O. Box 12000, Ein Kerem, Jerusalem il-91120, Israel b Department of Medical Engineering, The Hadassah-Hebrew University Medical School, P.O. Box 12000, Ein Kerem, Jerusalem il-91120, Israel Accepted 19 December 2004
Introduction Intramedullary nailing is the most commonly used technique for fixing femoral shaft fractures.17 Use of a fluoroscopy based computerised navigation system can improve the nailing technique by locating the entry point of the nail, inserting locking and Poller screws and providing accurate nail and screw measurements. These tasks then can be performed with markedly reduced radiation exposure.5,7,14 However, fracture reduction in vivo has not been achieved by computerised navigation systems, since dynamic imaging of two separate anatomic sites, such as fracture fragments, has not yet proved feasible. Open reduction can result in higher rates of infection and non-union.3,11,15 Several techniques have been suggested to accomplish closed reduction, such as the use of the femoral distractor,9,12 percutaneous Schanz screws to manipulate the fragments,2 and tourniquet. These solutions rely exclusively on fluoroscopy thus exposing both the patients and the surgeons to a significant amount of radiation.6,8,13 * Corresponding author. Tel.: +972 2 6778611; fax: +972 2 6423074. E-mail addresses: [email protected], [email protected] (R. Mosheiff).
We present a novel technique for closed reduction in intramedullary nailing utilising a fluoroscopy based computerised navigation system.
Surgical technique The ION Fluoronav1 StealthStation1 workstation (Medtronic Surgical Navigation Technologies Inc., Louisville, CO, USA) is a dedicated fluoroscopic computerised navigation unit. It includes a central computer, a position sensor comprised of an optical infrared tracking camera, and optical infrared emitting trackers attached to bone, surgical instruments and to a C-arm machine. The process of navigation involves rigidly fixing a bone tracker to the operated site. Several radiographic images are then taken while the surgical team is at a safe distance (over 2 m) from the radiation source. The position sensor must be triangulated with both the C arm and the bone tracker, which are equipped with infrared emitting diodes, in order to acquire the fluoroscopic images. The images are then processed by the computer, displayed virtually on the screen enabling navigation to commence. In the navigation process, a tracked instrument is manipulated and its image is simultaneously depicted on all the previously taken anatomy images of the patient.
0020–1383/$ — see front matter # 2004 Elsevier Ltd. All rights reserved. doi:10.1016/j.injury.2004.12.036
Computerised navigation for femoral intramedullary nailing
867
Figure 1 The instrument tracker (SureTrak 21) is attached to the intramedullary fracture alignment device. This cannulated device is inserted to the proximal fracture fragment.
Figure 2 During the navigation process, the fracture is being maniplulated by the intramedullary fracture alignment device that has been inserted into the proximal fragment (represented by a purple line). Its virtual extrapolation (represented by a green line) is aimed toward the distal fragment [‘‘DF’’]. Note that the residual fluoroscopic image of the proximal fragment [‘‘RF’’] on the computer screen is not tracked and should be ignored. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of the article.)
868 The SureTrak 21 system (Medtronic Surgical Navigation Technology Inc., Lousiville, CO, USA) is a modular infrared emitting active instrument tracker which can be mounted on any surgical instrument and enables its spatial tracking in relation to the patient’s anatomy by the computer. Contrary to predefined commercial tracked tools, any straight surgical instrument can be defined in real-time and displayed on previously acquired images. In order to achieve fracture reduction, the tracker is placed on a cannulated intramedullary fracture-aligning device and its configuration is registered by the computer (Fig. 1). The fracture-aligning device is actually a commercial reducer of second-generation reconstruction nail (Smith & Nephew, Memphis, TN, USA). The patient is positioned supine on a radiolucent table with a traction unit. A skeletal traction pin is placed in the proximal tibia thus maintaining length, and later on simplifies closed reduction. The preparation of nailing and location of the entry point can be done conventionally17 or by using computerised navigation as already described.7 After locating the entry point, the proximal fragment is reamed up to the diameter of the tracked
R. Mosheiff et al.
intramedullary fracture alignment device, which is then inserted into the medullary canal of the proximal fragment, advanced to the fracture site, and will at a later stage be used as a ‘‘joystick’’ for fracture reduction.15 A bone tracker is inserted into the distal segment of the fracture. Two fluoroscopic images (AP and lateral) of the distal fragment are taken and stored in the computer. The fluoroscope is now removed from the surgical field and will not be used throughout the reduction process. At the same time, the position sensor (infrared camera) is tracking the intramedullary fracture alignment device by locating the instrument tracker on it, and the distal fragment using the bone tracker. Since the intramedullary device is located inside the proximal fragment, its image represents both the device and the proximal fragment as a single unit. The image seen on the computer screen displays the tracked instrument only, but actually represents the proximal fragment surrounding it. This eliminates the need to fix a reference frame to the proximal fragment. The actual fracture reduction is then carried out by manipulating the proximal fragment, using the tracked intramedullary alignment device
Figure 3 The fragments are now aligned on both AP and lateral views and the fracture is actually reduced. The guide wire can be safely passed now into the distal fragment’s medullary canal.
Computerised navigation for femoral intramedullary nailing
and directing its virtual image on the computer screen towards the medullary canal of the distal fragment. While navigating, the images seen on the computer screen during the reduction process are the virtual image of the device and the distal fragment itself. The fracture is reduced when both images are aligned on both previously taken AP and lateral views (Figs. 2 and 3). The residual image of the proximal fragment seen in these figures should be ignored, since at this stage only the tracked intramedullary alignment device and the distal fragment are updated on the computer screen. It is stressed that the above procedure is entirely performed without the use of fluoroscopy. At this point the reduction has been accomplished; a reaming guide wire is passed through the intramedullary alignment device into the medullary canal of the distal segment. It should be pointed out that the distal fragment is constantly being tracked by the system since a dynamic reference frame is rigidly fixed to it. Therefore, movements of this fragment do not affect the accuracy of the reduction. A verification fluoroscopy is taken (Fig. 4). From this
869
point onwards, nailing continues in the standard fashion.
Discussion An innovative technique for long bone fracture reduction, based on computer assisted orthopaedic surgery (CAOS), with minimal exposure to radiation is presented here. Several authors have suggested techniques to overcome the obstacles of closed reduction. Manoeuvring of the proximal fragment by a small diameter nail or a customised tool designed for this application has been previously described.16 Recently, a technique for reducing femoral fracture by inserting percutaneous Schanz screws into the fragment and manually manipulating them was also published.2 The main disadvantage of these techniques is that they rely heavily on conventional fluoroscopy and its hazardous implications.5,7,8 One should keep in mind that a significant amount of radiation is being
Figure 4 Verification image of the aligned fracture after the insertion of guide wire. The overlapping of the verified location of the guide wire and the virtual image (purple line) confirms the accuracy of the procedure. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of the article.)
870
delivered to both the patient and the surgical team while reduction attempts are taking place, particularly to the surgeons’ hands.1,13 Some authors claim that this amount of radiation can seriously limit the permitted number of procedures for both surgeons and patients.1,5,7 The technique presented here is accurate and is based on a minimal number of fluoroscopic images. This technique has been implemented in a few cases and proved to be reliable especially in the reduction of transverse rather proximal femoral shaft fractures. The major drawback of this technique is the lengthy set up and registration process. The actual reduction time was reduced from 17 min in the first case to 2 min in the last one. No fluoroscopic images were taken until the guide wire was inside the medullary canal of the distal fragment. Existing computerised fluoroscopic based navigation platforms are gaining popularity in orthopaedic trauma practice and can be used as an ‘‘augmented fluoroscopy’’ with increased precision and reduced exposure to radiation.5,7,10 However, they do not allow the dynamic imaging of two separate anatomical structures such as fracture fragments. Thus, fracture reduction by computerised fluoroscopic based navigation has not been described to date. We introduce a technique that overcomes the drawbacks of the existing computer navigation systems. This technique is based on tracking standard available equipment for fracture reduction, eliminating the need for two separate bone trackers on both fracture fragments. Still, we think that tracking both fragments in a direct way will render navigated femoral shaft fracture reduction much more useful. Some experimental models have been constructed to improve fracture reduction and among them the use of CT based and combined fluoro and CT systems.4 However, these are still under laboratory studies and have been approved for clinical use. In the future, customised tracked instruments based on these principles will further improve and facilitate computer-assisted intramedullary nailing.
R. Mosheiff et al.
References 1. Coetzee JC, Van Der Merwe EJ. Exposure of surgeons-intraining to radiation during intramedullary fixation of femoral shaft fractures. S Afr Med J 1992;81:312—4. 2. Georgiadis GM, Burgar AM. Percutaneous skeletal joysticks for closed reduction of femoral shaft fractures during intramedullary nailing. J Orthop Trauma 2001;15(8): 570—1. 3. Harper MC. Fractures of the femur treated by open and closed intramedullary nailing using the fluted rod. J Bone Joint Surg Am 1985;67:699—708. 4. Hazan EJ, Joskowicz L. Computer-assisted image-guided intramedullary nailing of femoral shaft fractures. Tech Orthop 2003;18(2):191—200. 5. Kahler DM. Virtual fluoroscopy, a tool for decreasing radiation exposure during femoral intramedullary Nailing. Stud Health Technol Inform 2001;81:225—8. 6. Kahler DM. Image guidance: fluoroscopic navigation. Clin Orthop 2004;(421):70—6. 7. Khoury A, Liebergall M, Weil Y, Mosheiff R. Navigation assisted intramedullary nailing — the first generation. In: The 19th Annual Meeting of the Orthopaedic Trauma Association [abstract]. Salt Lake City, Utah, USA; 2003. p. 124. 8. Madan S, Blakeway C. Radiation exposure to surgeon and patient in intramedullary nailing of the lower limb. Injury (Engl) 2002;33(8):723—7. 9. McFerran MA, Johnson KD. Intramedullary nailing of acute femoral shaft fractures without a fracture table: technique of using a femoral distractor. J Orthop Trauma 1992;6:271—8. 10. Mosheiff R, Khouri A, Weil Y, Liebergall M. First generation computerised fluoroscopic navigation in percutaneous pelvic surgery. J Orthop Trauma 2004;18(2):106—11. 11. Schatzker J. Open intramedullary nailing of the femur. Orthop Clin North Am 1980;11:623—31. 12. Sirkin MS, Behrens F, McCracken K, et al. Femoral nailing without a fracture table. Clin Orthop 1996;332:119. 13. Skjeldal S, Backe S. Interlocking medullary nails–—radiation doses in distal targeting. Arch Orthop Trauma Surg 1987;106:179—81. 14. Suhm N, Messmer P, Zuna I, et al. Fluorsocopic guidance versus surgical navigation for distal locking of intramedullary implants. A prospective controlled clinical study. Injury 2003;35(6):567—74. 15. Whittaker RP, Heppenstall B, Menkowitz E, Montique F. Comparison of open vs closed rodding femurs utilizing a Sampson rod. J Trauma 1982;22:461. 16. Whittle AP. Fractures of the lower extremity. In: Campbell’s Operative Orthopaedics [chapter 51]. 10th ed. Mosby-Year Book: St. Louis; 2003. 17. Winquist RA, Hansen Jr ST, Clawson DK. Closed intramedullary nailing of femoral fractures: a report of five hundred and twenty cases. J Bone Joint Surg Am 1984;66:529—39.
www.elsevier.com/locate/injury
CASE REPORT
Computerised navigation for closed reduction during femoral intramedullary nailing Rami Mosheiff a,*, Yoram Weil a, Eran Peleg b, Meir Liebergall a a
Department of Orthopaedic Surgery, The Hadassah-Hebrew University Medical School, P.O. Box 12000, Ein Kerem, Jerusalem il-91120, Israel b Department of Medical Engineering, The Hadassah-Hebrew University Medical School, P.O. Box 12000, Ein Kerem, Jerusalem il-91120, Israel Accepted 19 December 2004
Introduction Intramedullary nailing is the most commonly used technique for fixing femoral shaft fractures.17 Use of a fluoroscopy based computerised navigation system can improve the nailing technique by locating the entry point of the nail, inserting locking and Poller screws and providing accurate nail and screw measurements. These tasks then can be performed with markedly reduced radiation exposure.5,7,14 However, fracture reduction in vivo has not been achieved by computerised navigation systems, since dynamic imaging of two separate anatomic sites, such as fracture fragments, has not yet proved feasible. Open reduction can result in higher rates of infection and non-union.3,11,15 Several techniques have been suggested to accomplish closed reduction, such as the use of the femoral distractor,9,12 percutaneous Schanz screws to manipulate the fragments,2 and tourniquet. These solutions rely exclusively on fluoroscopy thus exposing both the patients and the surgeons to a significant amount of radiation.6,8,13 * Corresponding author. Tel.: +972 2 6778611; fax: +972 2 6423074. E-mail addresses: [email protected], [email protected] (R. Mosheiff).
We present a novel technique for closed reduction in intramedullary nailing utilising a fluoroscopy based computerised navigation system.
Surgical technique The ION Fluoronav1 StealthStation1 workstation (Medtronic Surgical Navigation Technologies Inc., Louisville, CO, USA) is a dedicated fluoroscopic computerised navigation unit. It includes a central computer, a position sensor comprised of an optical infrared tracking camera, and optical infrared emitting trackers attached to bone, surgical instruments and to a C-arm machine. The process of navigation involves rigidly fixing a bone tracker to the operated site. Several radiographic images are then taken while the surgical team is at a safe distance (over 2 m) from the radiation source. The position sensor must be triangulated with both the C arm and the bone tracker, which are equipped with infrared emitting diodes, in order to acquire the fluoroscopic images. The images are then processed by the computer, displayed virtually on the screen enabling navigation to commence. In the navigation process, a tracked instrument is manipulated and its image is simultaneously depicted on all the previously taken anatomy images of the patient.
0020–1383/$ — see front matter # 2004 Elsevier Ltd. All rights reserved. doi:10.1016/j.injury.2004.12.036
Computerised navigation for femoral intramedullary nailing
867
Figure 1 The instrument tracker (SureTrak 21) is attached to the intramedullary fracture alignment device. This cannulated device is inserted to the proximal fracture fragment.
Figure 2 During the navigation process, the fracture is being maniplulated by the intramedullary fracture alignment device that has been inserted into the proximal fragment (represented by a purple line). Its virtual extrapolation (represented by a green line) is aimed toward the distal fragment [‘‘DF’’]. Note that the residual fluoroscopic image of the proximal fragment [‘‘RF’’] on the computer screen is not tracked and should be ignored. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of the article.)
868 The SureTrak 21 system (Medtronic Surgical Navigation Technology Inc., Lousiville, CO, USA) is a modular infrared emitting active instrument tracker which can be mounted on any surgical instrument and enables its spatial tracking in relation to the patient’s anatomy by the computer. Contrary to predefined commercial tracked tools, any straight surgical instrument can be defined in real-time and displayed on previously acquired images. In order to achieve fracture reduction, the tracker is placed on a cannulated intramedullary fracture-aligning device and its configuration is registered by the computer (Fig. 1). The fracture-aligning device is actually a commercial reducer of second-generation reconstruction nail (Smith & Nephew, Memphis, TN, USA). The patient is positioned supine on a radiolucent table with a traction unit. A skeletal traction pin is placed in the proximal tibia thus maintaining length, and later on simplifies closed reduction. The preparation of nailing and location of the entry point can be done conventionally17 or by using computerised navigation as already described.7 After locating the entry point, the proximal fragment is reamed up to the diameter of the tracked
R. Mosheiff et al.
intramedullary fracture alignment device, which is then inserted into the medullary canal of the proximal fragment, advanced to the fracture site, and will at a later stage be used as a ‘‘joystick’’ for fracture reduction.15 A bone tracker is inserted into the distal segment of the fracture. Two fluoroscopic images (AP and lateral) of the distal fragment are taken and stored in the computer. The fluoroscope is now removed from the surgical field and will not be used throughout the reduction process. At the same time, the position sensor (infrared camera) is tracking the intramedullary fracture alignment device by locating the instrument tracker on it, and the distal fragment using the bone tracker. Since the intramedullary device is located inside the proximal fragment, its image represents both the device and the proximal fragment as a single unit. The image seen on the computer screen displays the tracked instrument only, but actually represents the proximal fragment surrounding it. This eliminates the need to fix a reference frame to the proximal fragment. The actual fracture reduction is then carried out by manipulating the proximal fragment, using the tracked intramedullary alignment device
Figure 3 The fragments are now aligned on both AP and lateral views and the fracture is actually reduced. The guide wire can be safely passed now into the distal fragment’s medullary canal.
Computerised navigation for femoral intramedullary nailing
and directing its virtual image on the computer screen towards the medullary canal of the distal fragment. While navigating, the images seen on the computer screen during the reduction process are the virtual image of the device and the distal fragment itself. The fracture is reduced when both images are aligned on both previously taken AP and lateral views (Figs. 2 and 3). The residual image of the proximal fragment seen in these figures should be ignored, since at this stage only the tracked intramedullary alignment device and the distal fragment are updated on the computer screen. It is stressed that the above procedure is entirely performed without the use of fluoroscopy. At this point the reduction has been accomplished; a reaming guide wire is passed through the intramedullary alignment device into the medullary canal of the distal segment. It should be pointed out that the distal fragment is constantly being tracked by the system since a dynamic reference frame is rigidly fixed to it. Therefore, movements of this fragment do not affect the accuracy of the reduction. A verification fluoroscopy is taken (Fig. 4). From this
869
point onwards, nailing continues in the standard fashion.
Discussion An innovative technique for long bone fracture reduction, based on computer assisted orthopaedic surgery (CAOS), with minimal exposure to radiation is presented here. Several authors have suggested techniques to overcome the obstacles of closed reduction. Manoeuvring of the proximal fragment by a small diameter nail or a customised tool designed for this application has been previously described.16 Recently, a technique for reducing femoral fracture by inserting percutaneous Schanz screws into the fragment and manually manipulating them was also published.2 The main disadvantage of these techniques is that they rely heavily on conventional fluoroscopy and its hazardous implications.5,7,8 One should keep in mind that a significant amount of radiation is being
Figure 4 Verification image of the aligned fracture after the insertion of guide wire. The overlapping of the verified location of the guide wire and the virtual image (purple line) confirms the accuracy of the procedure. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of the article.)
870
delivered to both the patient and the surgical team while reduction attempts are taking place, particularly to the surgeons’ hands.1,13 Some authors claim that this amount of radiation can seriously limit the permitted number of procedures for both surgeons and patients.1,5,7 The technique presented here is accurate and is based on a minimal number of fluoroscopic images. This technique has been implemented in a few cases and proved to be reliable especially in the reduction of transverse rather proximal femoral shaft fractures. The major drawback of this technique is the lengthy set up and registration process. The actual reduction time was reduced from 17 min in the first case to 2 min in the last one. No fluoroscopic images were taken until the guide wire was inside the medullary canal of the distal fragment. Existing computerised fluoroscopic based navigation platforms are gaining popularity in orthopaedic trauma practice and can be used as an ‘‘augmented fluoroscopy’’ with increased precision and reduced exposure to radiation.5,7,10 However, they do not allow the dynamic imaging of two separate anatomical structures such as fracture fragments. Thus, fracture reduction by computerised fluoroscopic based navigation has not been described to date. We introduce a technique that overcomes the drawbacks of the existing computer navigation systems. This technique is based on tracking standard available equipment for fracture reduction, eliminating the need for two separate bone trackers on both fracture fragments. Still, we think that tracking both fragments in a direct way will render navigated femoral shaft fracture reduction much more useful. Some experimental models have been constructed to improve fracture reduction and among them the use of CT based and combined fluoro and CT systems.4 However, these are still under laboratory studies and have been approved for clinical use. In the future, customised tracked instruments based on these principles will further improve and facilitate computer-assisted intramedullary nailing.
R. Mosheiff et al.
References 1. Coetzee JC, Van Der Merwe EJ. Exposure of surgeons-intraining to radiation during intramedullary fixation of femoral shaft fractures. S Afr Med J 1992;81:312—4. 2. Georgiadis GM, Burgar AM. Percutaneous skeletal joysticks for closed reduction of femoral shaft fractures during intramedullary nailing. J Orthop Trauma 2001;15(8): 570—1. 3. Harper MC. Fractures of the femur treated by open and closed intramedullary nailing using the fluted rod. J Bone Joint Surg Am 1985;67:699—708. 4. Hazan EJ, Joskowicz L. Computer-assisted image-guided intramedullary nailing of femoral shaft fractures. Tech Orthop 2003;18(2):191—200. 5. Kahler DM. Virtual fluoroscopy, a tool for decreasing radiation exposure during femoral intramedullary Nailing. Stud Health Technol Inform 2001;81:225—8. 6. Kahler DM. Image guidance: fluoroscopic navigation. Clin Orthop 2004;(421):70—6. 7. Khoury A, Liebergall M, Weil Y, Mosheiff R. Navigation assisted intramedullary nailing — the first generation. In: The 19th Annual Meeting of the Orthopaedic Trauma Association [abstract]. Salt Lake City, Utah, USA; 2003. p. 124. 8. Madan S, Blakeway C. Radiation exposure to surgeon and patient in intramedullary nailing of the lower limb. Injury (Engl) 2002;33(8):723—7. 9. McFerran MA, Johnson KD. Intramedullary nailing of acute femoral shaft fractures without a fracture table: technique of using a femoral distractor. J Orthop Trauma 1992;6:271—8. 10. Mosheiff R, Khouri A, Weil Y, Liebergall M. First generation computerised fluoroscopic navigation in percutaneous pelvic surgery. J Orthop Trauma 2004;18(2):106—11. 11. Schatzker J. Open intramedullary nailing of the femur. Orthop Clin North Am 1980;11:623—31. 12. Sirkin MS, Behrens F, McCracken K, et al. Femoral nailing without a fracture table. Clin Orthop 1996;332:119. 13. Skjeldal S, Backe S. Interlocking medullary nails–—radiation doses in distal targeting. Arch Orthop Trauma Surg 1987;106:179—81. 14. Suhm N, Messmer P, Zuna I, et al. Fluorsocopic guidance versus surgical navigation for distal locking of intramedullary implants. A prospective controlled clinical study. Injury 2003;35(6):567—74. 15. Whittaker RP, Heppenstall B, Menkowitz E, Montique F. Comparison of open vs closed rodding femurs utilizing a Sampson rod. J Trauma 1982;22:461. 16. Whittle AP. Fractures of the lower extremity. In: Campbell’s Operative Orthopaedics [chapter 51]. 10th ed. Mosby-Year Book: St. Louis; 2003. 17. Winquist RA, Hansen Jr ST, Clawson DK. Closed intramedullary nailing of femoral fractures: a report of five hundred and twenty cases. J Bone Joint Surg Am 1984;66:529—39.