Accuracy study of computer-assisted drilling: the effect of bone density, drill bit characteristics, and use of a mechanical guide

OBJECTIVE: This study was designed to determine the clinical relevant accuracy of CT-based navigation for drilling. DESIGN: Experimental model. SETTING: Laboratory. METHODS: Twelve drills of varying lengths and diameters were tested with 2 different set-ups. Group 1 used free-hand navigated drilling technique with foam blocks equipped with titanium target points. Group 2 (control) used a newly developed 3-dimensional measurement device equipped with titanium target points with a fixed entry for the navigated drill to minimize bending forces. One examiner performed 690 navigated drillings using solely the monitor screen for control in both groups. The difference between the planned and the actual starting and target point (up to 150 mm distance) was measured (mm). STATISTICS: Levene test and a nonpaired t test. Significance level was set as P < 0.05. RESULTS: The core accuracy of the navigation system measured with the 3-dimensional device was 0.5 mm. The mean distance from planned to actual entry points in group 1 was 1.3 (range, 0.6-3.4 mm). The mean distance between planned and actual target point was 3.4 (range, 1.7-5.8 mm). Free-hand navigated drilling showed an increased difference with increased length of the drill bits as well as with increased drilling channel for drill bits 2.5 and 3.2 mm and not for 3.5 and 4.5 mm (P < 0.05). CONCLUSIONS: The core accuracy of the navigation system is high. Compared with the navigated free-hand technique, the results suggest that drill bit deflection interferes directly with the precision. The precision is decreased when using small diameter and longer drill bits.     

Decreased navigated drilling time using an external guide stabilising device

INTRODUCTION: Computer navigation in orthopaedic procedures can improve accuracy and decrease radiation time compared to traditional fluoroscopy. Many different applications are now available, and drilling is commonly used amongst them. Aside from additional set up time required, the drilling procedure itself may take a significant amount of time. We hypothesised that using an external stabilising guide which can be set anywhere in space can decrease then time necessary for navigated drilling. METHODS: Foam blocks, 80 mm in length and a density similar to cancellous bone, were obtained. Small discs were placed on one end as drilling targets. Using an Iso-C 3D navigation system, 20 navigated drilling trials were performed under each of two conditions: freehand, and with the use of a drill stabilising guide attached to an operating table. The time and accuracy of the two methods were compared. RESULTS: The time required for the entire navigation procedure was significantly less using the stabilising arm compared to drilling freehand with navigation (4.5 min versus 5.8 min, p=0.009). There was no significant difference in accuracy between the two methods. CONCLUSION: Using a guide which attaches to the table and allows the surgeon to fix the drill sleeve when the desired vector is chosen allows for faster navigated drilling. This was easy to set up and attach to the table, and did not diminish accuracy of drilling an intended target.     

Passive navigation principle for orthopedic interventions with MR fluoroscopy

Introduction

Of late, computer-assisted surgery has become a novel challenge for orthopedic surgeons. However, for orthopedic interventions magnetic resonance (MR) fluoroscopy is in its early stages of development. The authors have developed an innovative passive navigation concept, which is potentially applicable for many magnetic resonance image (MRI)-guided musculoskeletal interventions. With this method, no switching between different planes is required, since the cross-sectional modality of the MRI is used as a new navigation approach.

Materials and methods

This method was mainly evaluated in retrograde drilling of artificial osteochondral lesions of the talus as an example of difficult navigation in drill placement due to poor visualization with X-ray and complex anatomy. To accomplish this objective, a passive navigation device was constructed and evaluated in nine cadaveric ankle joint specimens. Feasibility and accuracy of navigated drillings were evaluated.

Results

The interactive high-field MR fluoroscopy and the passive aiming device allow precise drilling of osteochondral lesions of the talus, despite the complex anatomy of the ankle. Drillings could be performed with an accuracy of 1.6 mm. The drilling guide was safe and easy to handle.

Conclusion

The MR-assisted retrograde drilling of osteochondral lesions may enable precise and safe treatment without radiation exposure. This passive navigation technique for MR fluoroscopy is potentially applicable for many orthopedic interventions and may present an alternative to other navigation methods. Especially, the treatment of pediatric and adolescent patients may benefit from the typical MRI properties.     

Computer-assisted orthopedic surgery

 Computer-assisted surgery (CAS) utilizing robotic or image-guided technologies has been introduced into various orthopedic fields. Navigation and robotic systems are the most advanced parts of CAS, and their range of functions and applications is increasing. Surgical navigation is a visualization system that gives positional information about surgical tools or implants relative to a target organ (bone) on a computer display. There are three types of surgical planning that involve navigation systems. One makes use of volumetric images, such as computed tomography, magnetic resonance imaging, or ultrasound echograms. Another makes use of intraoperative fluoroscopic images. The last type makes use of kinetic information about joints or morphometric information about the target bones obtained intraoperatively. Systems that involve these planning methods are called volumetric image-based navigation, fluoroscopic navigation, and imageless navigation, respectively. To overcome the inaccuracy of hand-controlled positioning of surgical tools, three robotic systems have been developed. One type directs a cutting guide block or a drilling guide sleeve, with surgeons sliding a bone saw or a drill bit through the guide instrument to execute a surgical action. Another type constrains the range of movement of a surgical tool held by a robot arm such as ACROBOT. The last type is an active system, such as ROBODOC or CASPAR, which directs a milling device automatically according to preoperative planning. These CAS systems, their potential, and their limitations are reviewed here. Future technologies and future directions of CAS that will help provide improved patient outcomes in a cost-effective manner are also discussed. Received: October 28, 2002 RID="*"     

Tool parameters to minimize temperature changes in bone drilling

BackgroundDrilling is a common technique used in orthopedic surgery procedures but causes increases in temperature that can lead to cell damage and death. The extent of this depends largely on the magnitude of the increase in temperature. The commonly accepted limit to prevent osteonecrosis is less than 47 °C for 60 s. There is controversy when it comes to the optimal drilling parameters that limit temperature increases and cell death. In addition to this, less research has been done on the drilling effects in the osteochondral area of joints. Osteochondral tissue damage can interfere with the daily lives of patients and if severe enough will need to be treated. We hypothesize that increasing tool speed and drill bit size will increase temperature that could be above the osteonecrosis limit.MethodsEx-vivo experiments were conducted on porcine shoulder joints that tested the thermal effects of different tool speeds and drill bit sizes. A thermal camera was used to record and measure real time temperature changes while drilling. Three drill bit sizes and five tool speeds were used. Statistical analyses includes Welch's ANOVA with Games-Howell Post Hoc analyses, multivariate linear regression, and surface response regression were used to explore the association of tool speeds and drill bit size on temperature.Results and ConclusionsAll the tool speed and drill bit size combinations lead to an increase in temperature that were under the commonly accepted limit. The highest temperature reached was 44 °C with a tool speed of 1150 RPM and 3070 RPM and drill bit size 5.159 mm. It was found that increasing the tool speed increased the temperature change and increasing the drill bit size increased the temperature change.     

Accuracy of fluoroscopically navigated drilling procedures at the hip

AIM: Many orthopaedic procedures require an accurate drilling in bone. The outcome is frequently dependent on the geometric accuracy of this surgical step. The precision of such a procedure can be improved with the help of fluoroscopic navigation. Reliability, accuracy and benefit of this new method for the patient, as well as for the surgical staff, need to be analysed. METHOD: In a standardised in vitro trial, the drilling of a 5 mm spherical lesion implanted in an artificial femoral head was performed using a navigated drill-guide and a navigated drill. In groups A and B, the distance of the tip of the drill to the center of the lesion was analysed in a 3D CT-generated model and in macroscopic cross section. Additionally, in group B the actual direction of the drill canal was measured. RESULTS: The mean distance in group A was measured to be 1 mm, with all results ranging between 0 and 2.5 mm. In group B the planned direction of the canal was reproduced with a deviation of 0 degrees to 7 degrees, the target only being missed by a mean distance of 2.5 mm and a maximum of 3.5 mm. Compared to the macroscopic and 3D-CT findings, the correlation of the data calculated by the navigation system was accurate up to a difference of 4 degrees or 2 mm. CONCLUSION: The fluoroscopically assisted freehand navigation used during the drilling of bone led to a high accuracy of three-dimensional tip placement while reducing radiation exposure to a minimum. It represents a promising and efficient application for a variety of procedures in orthopaedic surgery.     

Präzision standardisierter Iso-C-Arm-basierter navigierter Bohrungen am proximalen Femur

C-arm navigation is a new tool in computer assisted surgery. The aim of this study is to evaluate the accuracy of Iso-C-arm based drill holes in the proximal femur. In nine artificial proximal femura, two holes with an angle of 135° and 100° in relation to the shaft axis were drilled in the direction of the femoral head. The defined target of the 3.2 mm drillings was a 4 mm steel ball, which had previously been placed and fixed at the cranial center of the femoral head. All the drillings were standardized with a navigated drilling machine fixed to a frame which only allowed movement of the system in the direction of the drill. During navigation the positions of the drill before commencement and at the deepest point of the canal were recorded. After drilling all specimens were evaluated by CT, and the coordinates of the center of the start and the end of the drilled hole and the center of the ball were determined. Using vector calculation, the smallest distance between the straight line, defined by the center of the starting point and the end point of the drill hole, and the center of the ball was calculated. Additionally, the coordinates of the intersection between the perpendicular to the center of the ball and the straight line were determined (x_v, y_v, z_v), to evaluate the direction of misplacement of the drilled canal in relation to the target. For the 135° drill holes, a median of 2.5 mm for the smallest distance between the straight line, given by the center of the start and the end of the hole, and the center of the ball was investigated (range 1.6 –3.7 mm). For the 100° holes the median was 3.1 mm (range 1.8 –4.2 mm). The main plane of deviation in all of the 135° holes was posteriorly, whereas in the 100° holes posterior deviation occurred in four cases, cranial in three cases, and in one case each caudal and anterior deviation occurred. In our opinion, the accuracy of fluoroscopy based navigation applied in the region of the proximal femur is sufficient and reproducible. This technique can be used for implant placement at the proximal femur in the future.     

Computer-assisted retrograde drilling of osteochondritic lesions of the talus with the help of fluoroscopic navigation

AIM: Due to the narrow access to the talar dome and the proximity of osteochondritic lesions to the joint surface, the therapeutic retrograde drilling often requires multiple attempts and repeated intraoperative X-ray-control. The advantages of a fluoroscopy-based computer-assisted navigation system regarding efficient planning and easy performance of the ideal drill path are evaluated in respect to accuracy and radiation exposure, as well as to time requirements. METHOD: A 5 mm spherical target was subcortically implanted in the medial aspect of the talar dome of 16 human cadaver specimens. Free-hand drilling was performed using the FluoroNav TM system in one group and conventional repetitive C-arm control in the other. The computed evaluation of the operative results was realized in a CT-generated 3D-model with the help of the DISOS planning and calculation program. The distance of the tip of the drill to the center of the lesion was measured, as well as X-ray exposure and total operating time. Results: The CAS procedure missed the lesion only once. The mean deviation of the computer-guided drill path was measured to be 2 mm, whereas the conventional method led to a mean distance of 5 mm from the target. Conventional drilling failed to reach the target in 5 cases, violating the articular cartilage twice. Navigation reduced the traditionally required multiple attempts of the intervention to just one drill canal and reduced radiation time to 25 %. Despite the increased technical preparation required, the navigated procedure only exceeded the conventional operating time by 2 minutes. CONCLUSION: Thanks to the significantly increased accuracy, fluoroscopic navigation offers a high degree of safety and efficacy for this minimally invasive procedure. The operation can easily be performed successfully causing only minimal collateral damage to the bone, preserving the joint surface. The inherent risks of the retrograde drilling of osteochondritic lesions are lower with navigation, while the radiation exposure of the patient and the staff is significantly reduced.     

Drilling, not a benign procedure: laboratory simulation of true drilling depth

IntroductionDrilling is an integral part of almost all boney operations. Various anatomical structures coursing close to the bone are at risk if the drill bit projects beyond the far cortex. Aim of this study was to evaluate and quantify the depth to which surgeons over drill beyond the far cortex.Materials and methodsDuring an AO course 153 (41 females, 112 males) surgeons and physicians were invited to participate in this study. Each participant performed 3 bicortical drillings on generic artificial bone. Polystyrene plates were mounted on the far cortex of the bone to allow for exact measurement of the over penetration of the drill bit.ResultsA total of 462 bicortical drilling manoeuvres were analysed. The average projection of the drill bit beyond the far cortex was 6.31 mm. No significant statistical correlation was noted between the specialty or the experience of the participant and depth of over drilling.ConclusionsIt is remarkable that the mean and the range of far cortex over-penetration was quite similar amongst surgeons of differing grades and experience. The results of this study should return to mind to pay attention when drilling particularly in anatomical sites where nerve and vessels coursing close to the far cortex.     

EndoButton drill bit failure

A case of an EndoButton drill bit failure associated with anterior cruciate ligament reconstruction using semitendinosus gracilis autograft is reported. The distal 10 mm flutes of the drill bit sheared off prior to graft passage. This event was likely related to repeated use of this bit, which is intended for single use only. This case highlights another potential pitfall associated with anterior cruciate ligament reconstruction.Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 18, No 3 (March), 2002: pp 322–324     

Cranionavigator combining a high-speed drill and a navigation system for skull base surgery--technical note

Drilling of the skull base bone without damaging the important inside structures and with the correct orientation is very difficult even with the help of the anatomical landmarks. Monitoring of the location and direction of the drill tip and indications of the removed part of the bone during the drilling procedure enhances safety and achieves less invasive neurosurgery. We have developed a novel cranionavigator by combining a high-speed drill with a neurosurgical navigation system. To reduce the positional error to less than 1.5 mm, the position sensor (magnetic field sensor) must be attached 5 cm from the metallic fan portion of the drill and the sensor kept at least 10 cm away from the operating microscope. Simulation studies with the cranionavigator using two dried skulls and three cadaver heads were performed before clinical application. Clinically, this surgical instrument was used in four patients with the skull base tumor. The cranionavigator helped to safely drill the skull base bone in a shorter time by dynamic and real-time display of the precise operating site and extent of bone drilling on the preoperative computed tomography scans or magnetic resonance images. The cranionavigator is a very helpful instrument for skull base surgery in the hands of neurosurgeons with extensive expertise and anatomical knowledge.     

Vascular risk associated with bicortical tibial drilling during anteromedial tibial tubercle transfer

For select patients with persistent patellofemoral pain, the anteromedial tibial tubercle transfer (Fulkerson osteotomy) provides excellent clinical results. This procedure, indicated for patients with patellar malalignment, has become one of the most popular distal realignment procedures. One potential concern with this technique is the proximity of the posterior vascular structures during bicortical tibial drilling for screw placement. To address this concern, we measured the proximity of these structures in 7 consecutive fresh-frozen cadaveric knees. For each knee, barium was injected into the femoral artery, and anteroposterior (AP) radiographs were taken to document the location of the popliteal vessels. Next, the initial steps of the Fulkerson osteotomy were performed. Then, a lateral release and the tibial osteotomy were performed, the tubercle was advanced into position, and two 9/64-inch extralong drill bits were placed through the tubercle and the posterior tibial cortex. Repeat AP radiographs were obtained, and digital calipers were used to measure the distance from the drill bits to the popliteal vessels. The vascular structure closest to the exit point of the superior drill bit was the bifurcation of the popliteal artery (mean distance, 8.3 mm; SD, 9.3 mm; range, 0.0-21.3 mm), and in 2 knees this structure directly overlay the bifurcation on the AP radiograph; the vascular structure closest to the exit point of the inferior drill bit was the posterior tibial artery (mean distance, 9.0 mm; SD, 8.0 mm; range, 0.0-20.0 mm), and again in 2 knees the drill bit lay directly over the artery on the AP radiograph. Bicortical drilling for screw placement during the anteromedial tibial tubercle transfer procedure may come precariously close to the posterior vascular structures of the knee, so orthopedic surgeons must take extreme caution not to drill past the posterior cortex during this part of the operation.     

Femoroacetabular impingement: role of imaging

Osteopetrosis is a rare skeletal condition first described by German radiologist Heinrich Albers-Schonberg. The most important technical difficulty is drilling due to hard bone in patients with osteopetrosis; recommendations have been made to use high-speed electric drill bits. But, the unavailability of this special drill bit in most of the centres makes the job more difficult. The study was conducted from 2009 to 2012; the cases are selected from Outpatients Department of Postgraduate Institute of Medical Education and Research. The patients were in the age group of 10–50 years with a mean age of 26 years. Five cases were included in the study: four patients had subtrochanteric fractures, and one had segmental fracture of the humerus. Open reduction and internal fixation was done in all the fractures using metal-cutting drill bit. The use of metal-cutting drill bit in osteopetrosis not only made our job easy but also prevented thermal necrosis of the bone to a large extent. The union rate was 100 % in our series, and there was no infection in any of our cases. In the treatment for fractures in osteopetrosis, the use of a metal-cutting drill bit along with careful attention to drilling technique can help avoid bit breakage and thermal bone injury that may produce ring sequestrum or destroy the already scant osteogenic cells.     

Die navigierte Scaphoidschraube

INTRODUCTION: Up to now, the use of navigation systems for the placement of scaphoid screws has been impossible, mainly because there have been no ways of fixing the reference markers. Faulty placement rates in internal fixation of the scaphoid show there is a current need for a 3D image-based navigation system and intraoperative monitoring of how successful the procedure will be. For this reason, we have developed a new radiotransparent hand fixation device (Scaph-Splint), which allows reliable and accurate drilling of the scaphoid using 3D navigation. Tests of this device and the simultaneous precise placement of screws securing an internal fixation device are described in this paper. MATERIAL AND METHODS: Relative movements between the wrist and fixation device were measured with a 3-D ultrasound motion analyser system. Five cadaveric upper extremity specimens were then used for further navigated test applications. Each specimen was placed in the fixation device, and both the forearm and hand were secured to the two surfaces, with the wrist in approximately 80 degrees of extension. A reference marker was then securely fixed to the fixation device. A commercial navigation system and 3-D fluoroscopic imaging were used for each trial. Under navigation, the scaphoid was drilled in retrograde fashion, and a screw was placed into the drilled hole. Following screw placement, a 3D scan was performed to evaluate its position. The screw placement was analysed blindly to optimal placement and drill or screw perforation, and the image quality was rated on a visual analog scale (VAS). RESULTS: There were few artefacts, and the image quality of the 3-D scan was judged as as good (VAS 79). Deviations of >or=0.2 mm between planned trajectory and drilling tunnal were not found in any of the specimens; there were deviations of >or=1 mm in one case, and all other cases showed deviations of 相似文献   

Computer-assisted navigation of total knee arthroplasty for osteoarthritis in a patient with severe posttraumatic femoral deformity

In the setting of extraarticular deformities of the knee, total knee arthroplasty (TKA) is difficult, as anatomical abnormalities obstruct identification of alignment landmarks and may preclude the use of traditional instrumentation. The long-term clinical value of computer assistance for TKA is a point of ongoing controversy. Few reports describe the use of computer-assisted orthopedic surgery as a method to decrease alignment outliers in TKA with associated posttraumatic deformities. In this report, a 70-year-old woman who had a severe distal femoral deformity from a previous open fracture underwent computer-assisted TKA for osteoarthritis. The use of a computer-assisted navigation system achieved a high degree of accuracy relative to the desired target alignment and led to improved function in a patient in which standard instrumentation was not feasible.     

Fluoroscopically based drilling of the femoral head in a model of adiposis.

OBJECTIVE: Exact drilling into the ischemic areas of necrotic lesions of the femoral head remains a challenging procedure, particularly in obese patients. This study was conducted to evaluate the precision of fluoroscopically based drilling and the associated radiation exposure in an in-vitro model of adiposis. MATERIALS AND METHODS: In an in-vitro model of necrotic lesions in adiposis, 20 sawbones were drilled under the guidance of an intraoperative navigation system (VectorVision, BrainLAB, Munich, Germany) and 20 more were drilled conventionally under fluoroscopic control only. RESULTS: A statistically significant difference was found with respect to the distance from the drill tip to the desired mid-point of the lesion, with a mean distance of 0.56 mm for the navigated group and 1.15 mm for the control group. Furthermore, a significant difference was found in the number of drilling corrections required, as well as the radiation exposure time: The navigated group required a mean of 0.35 second drillings or corrections of the drilling direction, compared to 2.45 for the control group, and the duration of radiation exposure was less than 1 second for the navigated group and 3.85 seconds for the control group. CONCLUSIONS: Drilling guided by the VectorVision navigation system shows high precision, even under difficult circumstances such as those encountered in adiposis, with a marked reduction in the duration of radiation exposure.     

Development and Application of an Inside-to-Out Drill Bit for Anterior Cruciate Ligament Reconstruction

We report a novel drilling device for anterior cruciate ligament (ACL) reconstruction that has been developed. We invented a special inside-to-out drill bit that can make a bone socket in an inside-to-out fashion. A blade at the tip of a 4.5-mm diameter drill bit closes when the drill bit is in orthograde rotation, but the blade opens when the drill bit is in reverse rotation. The special drill bit is introduced into the joint through a 4.5-mm diameter bone tunnel rotating the bit in the orthograde direction. Then the drill bit is switched to reverse rotation and is pulled backward so that it bores the bone from the inside out. We have used this special drill bit in treating 31 ACL-injured knees and have experienced no problems or complications with the procedure.     

Temperature changes and chondrocyte death during drilling in a bovine cartilage model and chondroprotection by modified irrigation solutions

Purpose

Drilling into cartilage/bone is often required for orthopaedic surgery. While drilling into bone has been studied, the response of cartilage has received little attention. We have measured cartilage and drill bit temperatures during drilling and quantified the zone of chondrocyte death (ZCD) around the hole in the presence/absence of irrigation solutions.

Methods

Drilling was performed using a 1.5-mm orthopaedic drill bit applied to bovine metatarsophalangeal joints and temperatures recorded by infrared camera. Osteochondral explants were then incubated with 5-chloromethylfluorescein diacetate (CMFDA) and propidium iodide (PI) to label living/dead chondrocytes respectively. The width of the ZCD was quantified by confocal laser scanning microscopy (CLSM) and image analysis.

Results

Without irrigation, the ZCD following drilling for two seconds was 135?±?15 μm and this increased (>fourfold, P?P?P?265 and 119 °C respectively, whereas the camera saturated at >282 °C during drilling for five seconds. With irrigation, the drill bit temperature was significantly reduced during drilling for two and five seconds (approx. 90 °C) with negligible change in cartilage temperature. Drilling while irrigating with hyperosmotic saline (600 mOsm) reduced (P?P?2+ saline (5 mM).

Conclusions

Reducing temperature during drilling by irrigation markedly suppressed, but did not abolish chondrocyte death. Optimising the irrigation solution by raising osmolarity and reducing Ca²⁺ content significantly reduced chondrocyte death during drilling and may be clinically beneficial.     

Surgical navigation based on fluoroscopy--clinical application for computer-assisted distal locking of intramedullary implants.

OBJECTIVE: Fluoroscopy is used to guide surgical instruments during orthopedic procedures. Radiation exposure and lack of spatial information are drawbacks of this method. Improvements are expected when fluoroscopy-based surgical navigation is used for intraoperative guidance, e.g., in computer-assisted distal locking of intramedullary implants. PATIENTS AND METHODS : The method was applied to 42 interlocking procedures during implantation of the short proximal femoral nail in 27 patients with pertrochanteric femoral fractures. Precision of interlocking, exposure time, operating time, and number of personnel required for computer-assisted distal locking were recorded. RESULTS: One misplaced interlocking screw was observed (2.3%), and contact between the drill bit and the nail during drilling was noticed in 8 cases (19%). The average exposure time was 16 seconds (range 4-42 seconds), and the procedure took an average of 43 min (range 20-70 min). The number of persons required for computer-assisted distal locking was reduced from three to one within the course of the study. CONCLUSIONS: Fluoroscopy-based surgical navigation provided precise intraoperative guidance for computer-assisted distal locking with minimal use of fluoroscopy. The complex system and related procedure times may be drawbacks in this application. Clinical studies are underway to define implants and surgical procedures where intraoperative guidance by fluoroscopy-based surgical navigation is beneficial for the patient and/or surgeon.     

计算机辅助导航全膝关节置换术的当前概念和进展

全膝关节置换术(TKR)旨在重建胫股和髌股关节的稳定性,缓解疼痛,改善患者生活质量.计算机辅助导航系统的应用能够有效减少常规TKR手术下肢力线重建中的人为错误并改善手术结果.现有证据表明,应用计算机辅助导航系统能够显著减少术后机械轴和冠状位假体位置的异常值.此外,导航系统提供了常规手术无法获得的软组织平衡客观评估.应用...