Intraoperative Fluoroscopic Images Research Articles

Do Fluoroscopy and Postoperative Radiographs Correlate for Periacetabular Osteotomy Corrections?

The Bernese periacetabular osteotomy (PAO) can relieve pain and restore function in patients with symptomatic acetabular dysplasia. Accurate acetabular correction is fundamental to achieving these clinical goals and presumably enhancing survivorship of the reconstruction. Fluoroscopy is used by some surgeons to assess intraoperative acetabular correction but it is unclear whether the features observed by fluoroscopy accurately reflect those on postoperative radiographs. We therefore determined whether the parameters of acetabular correction of PAO correlated on intraoperative fluoroscopic imaging and postoperative radiography. We retrospectively reviewed the imaging of 48 patients (50 hips) who underwent PAO. Intraoperative fluoroscopic AP and false profile images were obtained after final PAO correction. The intraoperative deformity correction as measured on the two fluoroscopy views was compared with the correction determined with postoperative standing plain AP pelvis and false profile radiographs using common measurements of acetabular position. Of all radiographic parameters, lateral center-edge angle had the highest correlation between intraoperative fluoroscopy and the postoperative radiograph with an intraclass correlation coefficient (ICC) of 0.80 (0.68-0.88). Similarly, acetabular inclination and anterior center-edge angle also correlated with ICCs of 0.76 (0.61-0.85) and 0.71 (0.54-0.82), respectively. Extrusion index and medial offset distance had lower correlations with ICCs of 0.66 (0.46-0.79) and 0.46 (0.21-0.65), respectively. Intraoperative fluoroscopic assessment of PAO correction correlated with that from the postoperative radiographic assessment. Measurement of lateral center-edge angle shows the highest correlation with the fewest outliers. Acetabular inclination and anterior center-edge angle also correlated; extrusion index and medial offset distance should be used with more caution.

In-hospital postoperative radiographs for instrumented single-level degenerative spinal fusions: utility after intraoperative fluoroscopy

There is a paucity of literature examining the clinical yield of in-hospital postoperative radiographs for patients who have had instrumented single-level spinal fusions with intraoperative fluoroscopic guidance. Many spinal surgeons consider postoperative standing radiographs to be the appropriate standard of care, even in patients who have an uneventful postoperative course. To evaluate the additional clinical yield and cost-effectiveness of in-hospital postoperative standing radiographs for patients undergoing instrumented single-level cervical and lumbar fusions in which intraoperative fluoroscopy is used. Are postoperative standing radiographs necessary before hospital discharge? Retrospective review of 100 consecutive degenerative spinal surgical cases in which intraoperative fluoroscopic imaging was compared with immediate postoperative radiographs using a vertebral grid mapping technique. A retrospective review of 100 consecutive patients who had an instrumented single-level cervical (30) or lumbar (70) fusion for a degenerative spinal condition performed by the same surgeon using intraoperative fluoroscopy. All patients had a documented uneventful postoperative hospitalization without evidence of new postoperative neurologic finding. All patients had both anteroposterior (AP) and lateral intraoperative fluoroscopic images and same-hospitalization standing AP and lateral radiographic images, which were performed within 72 hours postoperatively. Intraoperative and postoperative images were compared by two observers independently using a vertebral grid mapping technique to locate screw position and control magnification differences. Study parameters included screw tip position grids, interbody graft position, segmental sagittal plane alignment, spondylolisthesis grade, and hospital charges for patient imaging and interpretation. Early instrumentation failure and/or screw position change was not observed in any patient. Seventy-four patients demonstrated a grid match for all screw tip positions on both true AP and lateral radiographs. Twenty-six patients had either a postoperative AP or lateral radiograph that was clinically malrotated and precluded comparison with the intraoperative true fluoroscopic images. Segmental sagittal alignment difference between intraoperative fluoroscopic and postoperative radiographic sagittal images averaged only 1.2° (range, 0-9) and was not statistically significant (paired Student t test, p=.88). Significant difference between intraoperative and immediate postoperative interbody graft position and spondylolisthesis grade was not demonstrated in any patient. Patient hospital billing charges for postoperative AP and lateral radiographic imaging with interpretation averaged $600. In patients who have a single-level instrumented fusion and a documented uneventful postoperative course, in-hospital postoperative standing AP and lateral radiographs do not appear to provide additional clinically relevant information when intraoperative fluoroscopy is properly used. Fluoroscopy also demonstrated more consistent accuracy and a potential for significant cost savings.

Complex pediatric cervical spine surgery using smaller nonspinal screws and plates and intraoperative computed tomography

The treatment of craniocervical instability in children is often challenging due to their small spine bones, complex anatomy, and unique syndromes. The authors discuss their surgical experience with 33 cases in the treatment of 31 children (≤ 17 years of age) with craniocervical spine instability using smaller nontraditional titanium screws and plates, as well as intraoperative CT. All craniocervical fusion procedures were performed using intraoperative fluoroscopic imaging and electrophysiological monitoring. Nontraditional spine hardware included smaller screw sizes (2.4 and 2.7 mm) from the orthopedic hand/foot set and mandibular plates. Twenty-three of the 33 surgical procedures were performed with intraoperative CT, which was used to confirm adequate position of the spine hardware and alignment of the spine. The mean patient age was 9.5 years (range 2-17 years). Eleven children underwent a posterior C1-2 transarticular screw fusion, 17 had an occipitocervical fusion, and 3 had a posterior subaxial cervical fusion. The follow-up duration ranged from 9 to 72 months (mean 53 months). All children demonstrated successful fusion at their 3-month follow-up visit, except 1 patient whose unilateral C1-2 transarticular screw fusion required a repeat surgery before proper fusion was achieved. Of the 47 C1-2 transarticular screws that were placed, 13 were 2.4 mm, 15 were 2.7 mm, 7 were 3.5 mm, and 12 were 4.0 mm. Eighteen of the 47 C1-2 transarticular screws were suboptimally placed. Eleven of these misplaced screws were removed and redirected within the same operation because these surgeries benefitted from the use of intraoperative CT; 6 of the 7 remaining suboptimally placed screws were left in place because a second surgery for screw replacement was not warranted. The other suboptimally placed C1-2 screw was replaced during a repeat operation due to failure of fusion. Use of intraoperative CT was invaluable because it enabled the authors to reposition suboptimal C1-2 transarticular screws without necessitating a second operation. Successful craniocervical fusion procedures were achieved using smaller nontraditional titanium screws and plates. Intraoperative CT was a helpful adjunct for confirming and readjusting the trajectory of the screws prior to leaving the operating room, which decreases overall treatment costs and reduces complications.

Locked Plating of the Proximal Humerus Using an Endosteal Implant

To report on the use of a supplemental medial endosteal implant to prevent varus collapse and screw cutout in proximal humerus fractures treated with a laterally placed locking plate. Twenty-seven patients meeting study inclusion criteria were included in the study. Follow-up averaged 63.1 weeks (minimum 37 weeks and maximum 120 weeks). All patients were either older than 70 years or had sustained a proximal humerus fracture with medial comminution. Using the anterolateral acromial approach, a proximal humeral locking plate augmented with a medial endosteal implant (fibular allograft in 23 patients and semitubular plate in 4 patients) was used for fixation. Intraoperative fluoroscopic images and the most recent follow-up radiographs were used to measure the head-shaft angle and loss of height between the implant and the articular surface. Only 1 of 27 patients had significant loss of reduction with collapse of the fracture into varus (4.2 mm change). Ninety-six percent of patients maintained their original reduction with an average loss of height of 1.2 mm and an average change in shaft-head angle of 2.2 degrees. There were no implant failures or screw perforations of the articular surface and no radiographic or clinical evidence of AVN. Use of a medial endosteal implant as a supplement to a lateral locking plate is effective in maintaining operative reduction, preventing varus collapse, and implant failure in fractures with medial comminution and/or poor bone quality. Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

The Dorsal Horizon View: Detecting Screw Protrusion at the Distal Radius

Extensor tendon injury after osteosynthesis of distal radius fractures is a well-documented complication. It has been shown to be associated with screw protrusion through the dorsal cortex, or plunging of the drill bit into the overlying tendon. It is difficult to determine screw length and protrusion using the standard anteroposterior and lateral intraoperative fluoroscopic images because of the triangular configuration of the distal radius and Lister tubercle. In fractures with a coronal split, it may be necessary to lag the dorsal fragment, necessitating longer screws and risking screw protrusion beyond the dorsal cortex. For these fractures, we use a radiographic view aimed along the long axis of the radius to detect screw protrusion. This was a retrospective case series involving 15 distal radius fractures. To obtain the dorsal horizon view, the wrist is hyperflexed and the beam of the image intensifier is aimed along the long axis of the radius. We evaluated 15 distal radius fractures with a coronal split component, where the dorsal horizon view was used to detect dorsal cortex screw protrusion. This view was used intraoperatively following the use of the standard views. We evaluated records and imaging to ascertain whether the use of this radiograph led to a change in intraoperative screw selection. Of the 15 cases, we changed screw selection as a result of the additional view in 4 patients. In 3 of these cases, the screw length was long, which was not apparent on standard intraoperative fluoroscopic views. The use of the dorsal horizon view is a useful adjunct to prevent screw protrusion beyond the dorsal cortex when performing osteosynthesis of the distal radius.

Evaluation eines 2-D-Fluoroskopie-basierten Navigationssystems zur Implantation der dynamischen Hüftschraube (DHS): eine experimentelle Studie

Dynamic hip screw (DHS) insertion for the fixation of lateral femoral neck fractures is an accepted surgical treatment method. A computer-assisted planning and navigation system based on 2D fluoroscopy has been developed for guidewire insertion in order to perform screw placement. The image acquisition process was supported by a radiation-saving procedure called "zero-dose C-arm navigation". The aim of this study was to evaluate this new system. In the context of a sawbone study, we inserted dynamic hip screws. The procedure was performed under navigation control and in the conventional technique in 12 sawbones. Both procedures were performed in an open and closed technique. The computer-assisted technique significantly reduced the number of intraoperative fluoroscopic images (open technique: -8.1 ± 0.5; p < 0.001 - closed technique: -12.3 ± 3.7; p < 0.001) and the number of guidewire passes (open technique: -1.3 ± 1.2; p < 0.05 - closed technique: -1.5 ± 1.2; p < 0,05). There was no difference with respect to precision in both groups. The operationtime was significantly longer in the navigation-assisted groups (open technique: + 14.6 ± 5.4 min; p < 0.001 - closed technique: + 13 ± 3 min; p < 0.001). The addition of computer-assisted planning and surgical guidance supported by "zero-dose C-arm navigation" may be useful for the fixation of lateral femoral neck fractures by the DHS as it reduces the amount of fluoroscopic images and requires fewer drill tracks. Further studies with the goal of reducing the operation time are necessary.

A Comparison of CT-based Navigation Techniques for Minimally Invasive Lumbar Pedicle Screw Placement

A comparison of 2 surgical techniques. To determine the relative accuracy of minimally invasive lumbar pedicle screw placement using 2 different CT-based image-guided techniques. Three-dimensional intraoperative fluoroscopy systems have recently become available that provide the ability to use CT-quality images for navigation during image-guided minimally invasive spinal surgery. However, the cost of this equipment may negate any potential benefit in navigational accuracy. We therefore assess the accuracy of pedicle screw placement using an intraoperative 3-dimensional fluoroscope for guidance compared with a technique using preoperative CT images merged to intraoperative 2-dimensional fluoroscopy. Sixty-seven patients undergoing minimally invasive placement of lumbar pedicle screws (296 screws) using a navigated, image-guided technique were studied and the accuracy of pedicle screw placement assessed. Electromyography (EMG) monitoring of lumbar nerve roots was used in all. Group 1: 24 patients in whom a preoperative CT scan was merged with intraoperative 2-dimensional fluoroscopy images on the image-guidance system. Group 2: 43 patients using intraoperative 3-dimensional fluoroscopy images as the source for the image guidance system. The frequencies of pedicle breach and EMG warnings (indicating potentially unsafe screw placement) in each group were recorded. The rate of pedicle screw misplacement was 6.4% in group 1 vs 1.6% in group 2 (P=0.03). There were no cases of neurologic injury from suboptimal placement of screws. Additionally, the incidence of EMG warnings was significantly lower in group 2 (3.7% vs. 10% (P=0.03). The use of an intraoperative 3-dimensional fluoroscopy system with an image-guidance system results in greater accuracy of pedicle screw placement than the use of preoperative CT scans, although potentially dangerous placement of pedicle screws can be prevented by the use of EMG monitoring of lumbar nerve roots.

Lateral Ankle Radiographs: Do We Really Understand What We Are Seeing?

To evaluate the validity of using lateral intraoperative fluoroscopic imaging to assess the reduction of the tibial plafond articular surface, two hypotheses were tested: 1) the distal tibial subchondral shadow on the lateral ankle radiograph is created equally by the medial, central, and lateral portions of the distal tibia; and (2) displacement of a 5-mm width osteochondral fragment is consistently recognizable on lateral fluoroscopic imaging. Six human fresh-frozen tibial plafond cadaveric specimens were sagitally sectioned in 5-mm increments after removal of the anterior soft tissue and stabilization of the position of the ankle through external fixation. To test the first hypothesis, a perfect lateral radiograph was taken after sectioning the specimens. The sagittal sections were then removed sequentially from medial to lateral. A perfect lateral radiograph was taken after each change. The sagittal sections were then removed beginning laterally and moving medially. A perfect lateral radiograph was taken after each change. The images were then compared with specific evaluation of the change in the subchondral shadow density. To test the second hypothesis, three malreductions were created by displacing a 5-mm osteochondral segment. After each malreduction, a perfect lateral radiograph was saved. These saved fluoroscopic images were placed in random order with lateral images of normal specimens. Four experienced ankle surgeons were then asked to determine whether the radiographs revealed displacement. Inter- and intraobserver reliability was then evaluated. First, the subchondral shadow of the distal tibia appears to be created by an equal confluence of the subchondral bone of the medial, central, and lateral aspects of the tibial plafond. Second, fellowship-trained observers experienced in pilon fracture treatment correctly identified malreduction only 45% of the time. Intraclass correlation coefficient revealed very poor interobserver reliability with an alpha reliability statistic of 0.183. Intraobserver reliability across all four observers yielded an alpha statistic of 0.474, indicating inconsistencies in observers' evaluation of identical images at separate viewings. It is difficult to discern rotational or translational displacement of a 5-mm osteochondral fragment on a perfect lateral fluoroscopic view of the ankle. Even with what appears to be a perfect lateral fluoroscopic view intraoperatively, displacement may still be present. When small osteochondral fragments are present, direct visualization of the articular surface is necessary to confidently establish that an anatomic reduction has been achieved.

Multiple-Object 2-D–3-D Registration for Noninvasive Pose Identification of Fracture Fragments

This paper presents a multiple-object 2-D-3-D registration technique for noninvasively identifying the poses of fracture fragments in the space of a preoperative treatment plan. The plan is made by manipulating and aligning computer models of individual fracture fragments that are segmented from a diagnostic computed tomography. The registration technique iteratively updates the treatment plan and matches its digitally reconstructed radiographs to a small number of intraoperative fluoroscopic images. The proposed approach combines an image similarity metric that integrates edge information with mutual information, and a global-local optimization scheme, to deal with challenges associated with the registration of multiple small fragments and limited imaging orientations in the operating room. The method is easy to use as minimum user interaction is required. Experiments on simulated fractures and two distal radius fracture phantoms demonstrate clinically acceptable target registration errors with capture range as large as 10 mm.

Image-guided navigation in orthopaedic trauma

Fluoronavigation is an image-guided technology which uses intra-operative fluoroscopic images taken under a real-time tracking system and registration to guide surgical procedures. With the skeleton and the instrument registered, guidance under an optical tracking system is possible, allowing fixation of the fracture and insertion of an implant. This technology helps to minimise exposure to x-rays, providing multiplanar views for monitoring and accurate positioning of implants. It allows real-time interactive quantitative data for decision-making and expands the application of minimally invasive surgery. In orthopaedic trauma its use can be further enhanced by combining newer imaging technologies such as intra-operative three-dimensional fluoroscopy and optical image guidance, new advances in software for fracture reduction, and new tracking mechanisms using electromagnetic technology. The major obstacles for general and wider applications are the inability to track individual fracture fragments, no navigated real-time fracture reduction, and the lack of an objective assessment method for cost-effectiveness. We believe that its application will go beyond the operating theatre and cover all aspects of patient management, from pre-operative planning to intra-operative guidance and postoperative rehabilitation.

Navigation-assisted fluoroscopy in minimally invasive direct lateral interbody fusion: a cadaveric study

Background Minimally invasive surgery (MIS) is dependent on intraoperative fluoroscopic imaging for visualization, which significantly increases exposure to radiation. Navigation-assisted fluoroscopy (NAV) can potentially decrease radiation exposure and improve the operating room environment by reducing the need for real-time fluoroscopy. The direct lateral interbody fusion (DLIF) procedure is a technique for MIS intervertebral lumbar and thoracic interbody fusions. This study assesses the use of navigation for the DLIF procedure in comparison to standard fluoroscopy (FLUORO), as well as the accuracy of the NAV MIS DLIF procedure. Methods Three fresh whole-body cadavers underwent multiple DLIF procedures at the T10-L5 levels via either NAV or FLUORO. Radiation exposure and surgical times were recorded and compared between groups. An additional cadaver was used to evaluate the accuracy of the NAV system for the DLIF procedure by measuring the deviation error as the surgeon worked further from the anterior superior iliac spine tracker. Results Approach, discectomy, and total fluoroscopy times for FLUORO were longer than NAV ( P < .05). In contrast, the setup time was longer in NAV ( P = .005). Cage insertion and total operating times were similar for both. Radiation exposure to the surgeon for NAV was significantly less than FLUORO ( P < .05). Accuracy of the NAV system was within 1 mm for L2-5. Conclusion Navigation for the DLIF procedure is feasible. Accuracy for this procedure over the most common levels (L2-5) is likely sufficient for safe clinical application. Although initial setup times were longer with NAV, simultaneous anteroposterior and lateral imaging with the NAV system resulted in overall surgery times similar to FLUORO. Navigation minimizes fluoroscopic radiation exposure. Clinical significance Navigation for the DLIF procedure is accurate and decreases radiation exposure without increasing the overall surgical time.

Aortic valve prosthesis tracking for transapical aortic valve implantation

Transapical aortic valve implantation (TA-AVI) is a new minimally invasive surgical treatment of aortic stenosis for high-risk patients. The placement of aortic valve prosthesis (AVP) is performed under 2D X-ray fluoroscopic guidance. Difficult clinical complications can arise if the implanted valve is misplaced. Therefore, we present a method to track the AVP in 2D X-ray fluoroscopic images in order to improve the accuracy of the TA-AVI. The proposed tracking method includes the template matching approach to estimate the position of AVP and a shape model of the prosthesis to extract the corner points of the AVP in each image of sequence. To start the AVP tracking procedure, an initialization step is performed by manually defining the corner points of the prosthesis in the first image of sequence to provide the required algorithm parameters such as the AVP model parameters. We evaluated the AVP tracking method on six 2D intra-operative fluoroscopic image sequences. The results of automatic AVP localization agree well with manually defined AVP positions. The maximum localization errors of tracked prosthesis are less than 1mm and within the clinical accepted range. For assisting the TA-AVI, a method for tracking the AVP in 2D X-ray fluoroscopic image sequences has been developed. Our AVP tracking method is a first step toward automatic optimal placement of the AVP during the TA-AVI.

Comparison of percutaneous balloon compression and glycerol rhizotomy for the treatment of trigeminal neuralgia

The aim of this study was to compare percutaneous balloon compression (PBC) and percutaneous retrogasserian glycerol rhizotomy (PRGR) in terms of effectiveness, complications, and technical aspects. Sixty-six consecutive PBC procedures were performed in 45 patients between January 2004 and December 2008, and 120 PRGR attempts were performed in 101 patients between January 2006 and December 2008. The PRGR procedures were not completed due to technical reasons in 19 cases. Five patients in the Balloon Compression Group and 9 patients in the Glycerol Group were lost to follow-up and were excluded from the study. The medical records and the intraoperative fluoroscopic images from the remaining cases were retrospectively examined, and the follow-up was completed with telephone contact, when necessary. The 2 groups were compared in terms of initial effect, duration of effect, and rates of complications as well as severity and type of complications. The rates for immediate pain relief were 87% for patients treated with glycerol injection and 85% for patients treated with balloon compression. The Kaplan-Meier plots for the 2 treatment modalities were similar. The 50% recurrence time was 21 months for the balloon procedure and 16 months for the glycerol procedure. When the groups were broken down by the "previous operations" criterion, the 50% recurrence time was 24 months for the Glycerol First Procedure Group, 6 months for the Balloon First Procedure Group, 8 months for the Glycerol Previous Procedures Group, and 21 months for the Balloon Previous Procedures Group. The rates of complications (excluding numbness) were 11% for PRGR and 23% for PBC, and this difference was statistically significant (chi-square test, p = 0.04). Both PRGR and PBC are effective techniques for the treatment of trigeminal neuralgia, with PRGR presenting some advantages in terms of milder and fewer complications and allowing lighter anesthesia without compromise of analgesia. For these reasons the authors consider PRGR as the first option for the treatment of trigeminal neuralgia in patients who are not suitable candidates or are not willing to undergo microvascular decompression, while PBC is reserved for patients in whom the effect of PRGR has proven to be short or difficult to repeat due to cisternal fibrosis.

Registration between ultrasound and fluoroscopy or CT in prostate brachytherapy

In prostate brachytherapy, transrectal ultrasound (TRUS) is used to visualize the anatomy, while implanted seeds can be visualized by fluoroscopy. Intraoperative dosimetry optimization is possible using a combination of TRUS and fluoroscopy, but requires localization of the fluoroscopy-derived seed cloud, relative to the anatomy as seen on TRUS. The authors propose to develop a method of registration of TRUS images and the implants reconstructed from fluoroscopy. A phantom was implanted with 48 seeds then imaged with TRUS and CT. Seeds were reconstructed from CT yielding a cloud of seeds. Fiducial-based ground-truth registration was established between the TRUS and CT. TRUS images are filtered, compounded, and registered to the reconstructed implants by using an intensity-based metric. The authors evaluated a volume-to-volume and point-to-volume registration scheme. In total, seven TRUS filtering techniques and three image similarity metrics were analyzed. The method was also tested on human subject data captured from a brachytherapy procedure. For volume-to-volume registration, noise reduction filter and normalized correlation metrics yielded the best result: An average of 0.54 +/- 0.11 mm seed localization error relative to ground truth. For point-to-volume registration, noise reduction combined with beam profile filter and mean squares metrics yielded the best result: An average of 0.38 +/- 0.19 mm seed localization error relative to the ground truth. In human patient data, C-arm fluoroscopy images showed 81 radioactive seeds implanted inside the prostate. A qualitative analysis showed clinically correct agreement between the seeds visible in TRUS and reconstructed from intraoperative fluoroscopy imaging. The measured registration error compared to the manually selected seed locations by the clinician was 2.86 +/- 1.26 mm. Fully automated registration between TRUS and the reconstructed seeds performed well in ground-truth phantom experiments and qualitative observation showed adequate performance on early clinical patient data.

Lateral Tilt Wrist Radiograph Using the Contralateral Hand to Position the Wrist After Volar Plating of Distal Radius Fractures

Lateral tilt (radially inclined) radiographs are useful after volar locked plate fixation of distal radius fractures to assess the radiocarpal joint, subchondral bone congruity, and volar tilt. The purpose of our study was to define the reliability of our positioning method using the patient's opposite hand to position the injured wrist to obtain an inclined lateral radiograph with good visualization of the subchondral bone. A retrospective review identified adult patients who had a unilateral distal radius fracture treated with a volar locked plate and who had an initial postoperative lateral tilt radiograph using the contralateral hand to position the injured wrist. Intraoperative fluoroscopic images were reviewed to confirm the ability to see the extra-articular placement of all hardware. The inclined lateral wrist radiograph was obtained by positioning the injured wrist at a height determined by the contralateral hand being placed under the ulnar wrist crease. The wrist was then supported there with firm blocks in all cases. The radiographic beam was directed perpendicular to the horizontal cassette. Two reviewers (authors) then blindly reviewed postoperative radiographs to determine whether the radiocarpal joint and subchondral bone were visualized and whether any screws or pegs appeared to cross the radiocarpal joint. An acceptable lateral tilt radiograph was defined as good visualization of the subchondral bone while allowing only the most radial peg to appear to cross the joint. We also placed 15 normal volunteers into the lateral tilt position, using their opposite hand, to measure the inclined forearm angle. A total of 24 wrists (24 patients) were identified and 23 patients had lateral tilt radiographs with acceptable visualization of the subchondral bone. The concordance of the subchondral bone visualization was 100% (95% confidence interval, 85.5% to 100%). The mean angle with lateral tilt positioning was 18 degrees from horizontal (range, 15 degrees to 23 degrees; standard deviation, 2.4 degrees). Using the contralateral hand to position the lateral inclined view, our lateral tilt position produced radiographs with reliable visualization of the distal radius subchondral bone in 96% of our cases. Visualization of the subchondral bone in the region of the radial aspect of the scaphoid fossa requires more tilt than is achieved with this technique.

Sustentaculum-tali-Schraubenplatzierung bei der Versorgung von Kalkaneusfrakturen – verschiedene Navigationsverfahren im Vergleich zur konventionellen Technik

Precise placement of the sustentaculum tali screw is essential for fixation of calcaneus fractures to achieve the best fixation strength. In the clinical practice, this procedure is demanding due to the complex anatomic configuration of the calcaneus and the limited visualisation in the intraoperative fluoroscopic images. The aim of this study was an evaluation of the accuracy for the sustentaculum tali screw placement by using different navigation procedures compared to the standard procedure. The different navigation specific workflows were evaluated and the feasibility of each procedure proven in clinical applications. Eight sustentaculum screws per group were placed in an artifical Synbone model. Different navigation procedures were evaluated: 2D-fluoroscopy (group I), 3D-fluoroscopy (group II), fluoro-free (group III) and compared to the conventional screw placement without navigation (group IV). For each screw the time of fluoroscopy and the duration of the procedure were measured. The accuracy was evaluated postoperatively by computed tomography using axial slices and coronary as well as sagittal reformations. Furthermore, the workflow of each navigation procedure was analysed and proven in clinical applications. In the experimental setup, no radiation exposure was mandatory for the conventional and fluoro-free procedures, whereas mean fluoroscopy times of 17 +/- 1.03 und 66.8 +/- 0.9 were measured for 2D- and 3D-navigation procedures. In line with this, the overall mean procedure times for the screw placement were 1.26 +/- 0.05 (group IV), 3.49 +/- 0.26 (group III), 13.32 +/- 0.49 (group I) und 19.04 +/- 1.41 minutes (group II). No significant differences were observed for the accuracy of screw placement. In the clinical practice a better orientation was achieved by use of a navigation system. The fluoro-free procedure can be easily integrated into the common operation workflow, whereas the workflow of both image-based navigation procedures is technically demanding. Navigation procedures seem to be helpful for the precise placement of sustentaculum tali screws in cases of operative calcaneus fracture fixation. The kind of application to be used depends on the infrastructure of the department and the navigation-experience of the operating room team. Whereas the fluoro-free procedure is intuitive in use, the 2D-navigation does not justify the extra efforts. The 3D-procedure is the recommended application for surgeons familiar with navigation, providing the best orientation due to the slice image visualisation in all three dimensions.

What is the role of intra-operative fluoroscopic measurements to determine tibial tunnel placement in anatomical anterior cruciate ligament reconstruction?

The hypothesis for this study was that intra-operative fluoroscopic measurements can be used to determine tibial tunnel placement during anatomic anterior cruciate ligament (ACL) reconstruction. The anteromedial (AM) and posterolateral (PL) bundle insertion sites were marked with a thermal device and measured in a consecutive cohort of 67 patients undergoing anatomical ACL reconstruction. For double bundle reconstruction, guide pins were passed in the center of the AM and PL tibial footprints. For single bundle (SB) reconstruction a guide wire was placed between the center of AM and PL footprints. Subsequently, the position of the centers of the AM and PL insertion sites were measured on standardized lateral intra-operative fluoroscopic images. The center for the AM bundle was found to be at 31% (range 20-42%) of the AP distance on the medial joint line and at 35% (range 23-42%) of the AP distance on the Amis and Jakob line. The center of the PL bundle was at 48% (range 37-59%) of the AP distance on the medial joint line and 48% (range 39-58%) of the AP distance on the Amis and Jakob line. The center of the tibial tunnel in the SB group (n = 15) was at 42 and 41% in relation to the medial joint line and the Amis and Jakob line, respectively. Because a significant anatomic variation exists between patients, the decision with respect to tunnel placement should not be merely based on intra-operative fluoroscopic images.

Use of locking plates in the treatment of proximal humerus fractures

Open reduction and internal fixation (ORIF) using locked plating has demonstrated promise in the treatment of displaced proximal humerus fractures. The purpose of this article is to describe the surgical technique and to report early clinical results with this technique. Important surgical principles to follow include adequate use of locking screws in the humeral head, bone graft or bone graft substitutes when needed, rotator cuff sutures to assist with reduction and augment fixation, and sufficient use of intraoperative fluoroscopic imaging. A review was performed to evaluate early outcomes of ORIF with proximal humerus locking plates. All cases were fixed with the described surgical technique. Postoperative assessment included radiographic imaging, PENN/ASES Shoulder Scores, range-of-motion (ROM), and complications. Fifty-two patients (54 shoulders) had minimum 6-month follow-up (13-month mean follow-up). Mean age was 65.5 years. Postoperatively, mean active forward elevation was 130.1 degrees, and mean active external rotation was 27.7 degrees. Mean post-op PENN shoulder score was 68.9 and mean post-op ASES score was 70.8. There were 11 (20.4%) complications in 10 (18.5%) shoulders after treatment with a proximal humerus locking plate. Three complications were classified as minor (5.6%), 8 as major (14.8%). Two shoulders (3.7%) required reoperation to address the complications. The use of locking plates in the treatment of displaced proximal humerus fractures is becoming more widespread. With precise knowledge of and experience with the surgical technique, locked plating can be performed safely with good results. However, surgeons should be aware that complications can arise.

Femoral Radiographic Landmarks for Lateral Collateral Ligament Reconstruction and Repair

Background Little work has been made regarding the use of radiographic landmarks in fibular collateral ligament reconstruction. Radiographic tools can be of use to the surgeon in posterolateral reconstruction as secondary checks in the setting of tissue and bony attrition. Hypothesis Using standardized radiographic imaging, a zone for femoral tunnel placement in lateral collateral ligament (LCL) reconstruction can be identified. Study Design Descriptive laboratory study. Methods Eight fresh-frozen unmatched knees, free of any osseous or articular pathological changes, were selected for dissection (mean age, 61.3 years). Skin and surrounding soft tissues were left intact. Subsequent dissection was carried out to identify the true origin of the LCL. A radiographic marker was applied. True lateral radiographs of the distal femur (posterior condyles overlapping) were taken. Digital radiographic images were obtained and analyzed. Results The Blumensaat line was found to be closely associated with the LCL origin on lateral radiographic imaging. On average, the LCL ligament was found to be 58% (±4.7%) across the width of the condyle and 2.3 mm (±2.3 mm) distal to the Blumensaat line. In all specimens, the anatomical LCL origin was found to have less than 5 mm variance from the mean. Conclusion The LCL origin is located within a specific region that is noted to have a small amount of variance. This is of benefit to the clinician in the traumatic and reconstructive setting where the true origin may not be easily identifiable through dissection. Clinical Relevance Intraoperative fluoroscopic imaging can be used as an adjunctive tool for femoral tunnel placement during posterolateral corner and LCL reconstruction.

Percutaneous compressive screw fixation for float injury to pubic symphysis

Objective To discuss the functional results of percutaneons compressive screw fixation for float injury to the pubic symphysis. Methods From March 2003 to March 2007, 48 cases of float injury to the pubic symphysis were treated with percutaneons compressive screws, including 27 males and 21 females with an average age of 29.4 years. Of them, 39 eases were complicated with injury to the pelvic posterior ring. Emergency surgery was done for 13 cases, 27 cases were operated on within 3 to 7 days after injury and 8 within 7 to 14 days. Guided pins and screws were used during dosed reduction and percutaneous pelvic fixation was done under the guidance of intraoperative fluoroscopic imaging. Float injury to the pubic symphysis was amended by percutaneous fixation after dosed manipulation. Results The average operation time for the48 patients was 55 (31 to 100) min. The intraoperative bleeding averaged 20 to 30 mL. Satisfactory reduetian and fixation was achieved in 41 cases, but 7 cases had poor reduction. All the fractures healed 3 to 6 months postoperatively without infection, nonunion or injury to vessels, nerves or organs. All the patients could turn the body freely in bed the day after operation. Those without injury to the pelvic posterior ring could walk with crutches 3 days after operation. By the Orlando evaluation system for pelvic fractures, 37 eases were rated as excellent, 7 as good, 3 as fair and I as poor. Conclusions The percutaneous compressive screw fixation may decompress the pelvic hematoma, allowing early definitive fixation without the risk of additional hemorrhage. Complications associated with open posterior pelvic surgical procedures may be avoided by using percutaneons techniques. Key words: Pelvis; Surgical procedure, minimally invasive; Public symphysis