3D Fluoroscopic Navigation Research Articles

Accuracy in Navigated Percutaneous Sacroiliac Screw Fixation: A Systematic Review and Meta-Analysis

Abstract Background Percutaneous sacroiliac screw placement is a challenging procedure in patients with pelvic fractures. To overcome these challenges, navigated techniques have emerged as an alternative to conventional 2D fluoroscopy for guiding screw placement. However, it remains to be seen whether navigated techniques truly have a beneficial effect on accuracy, radiation exposure and occurrence of complications. Aims We performed a meta-analysis to investigate whether navigated techniques are superior to conventional 2D fluoroscopy in percutaneous sacroiliac screw fixation. Methods The electronic databases were searched for both randomized clinical trials and observational studies comparing percutaneous sacroiliac screw fixation with 2D fluoroscopy to new navigated techniques (2D or 3D fluoroscopic navigation with a c-arm, computer assisted ultrasound navigation, O-Arm navigation, mobile CT navigation, robotic navigation). Effects were pooled and presented as odds ratio, mean difference, and standardized mean difference with corresponding 95% confidence interval. Results In total 18 studies were included. New navigated techniques had a higher accuracy (81% versus 91% with MD 10%, 95% CI 5-14%). The greatest benefit in accuracy was found in studies with more advanced navigated techniques (O-Arm, mobile CT or robotic navigation). Also, fluoroscopy time (MD 72.13 seconds, 95% CI 7.73;92.91) and fluoroscopy frequency (MD 17.22 images in total, 95% CI 7.73;26.70) were lower for new navigated techniques. Radiation dose was higher for new navigated techniques (SMD 0.50, 95% CI 0.01;0.99). Surgery duration showed no significant difference. Similar results were found among in vitro studies. Complications were rare in both groups. Conclusion This meta-analysis demonstrated a higher accuracy of screw positioning, lower fluoroscopic frequency and time for navigated percutaneous sacroiliac screw fixation compared to conventional 2D fluoroscopy. Complications are acceptably low for both groups. Future studies should focus on which of the navigated techniques is the best and whether the implementation costs of a new technique outweigh its benefits.

Real-time three-dimensional fluoroscopy-navigated percutaneous pelvic screw placement for fragility fractures of the pelvis in the hybrid operating room

BackgroundThe prognosis of conservative treatment for fragility fracture of the pelvis (FFP) in the older patients remains poor. Percutaneous pelvic screw placement (PPSP), which aids in the treatment of FFP, can be challenging to perform using fluoroscopy alone because of the proximity of blood vessels and neuroforamina. Hence, this study aimed to investigate the accuracy and clinical outcomes of PPSP using real-time 3D fluoroscopic navigation for FFP in the hybrid operating room.MethodsThis study included 41 patients with FFP who underwent PPSP in a hybrid operating room between April 2016 and December 2020. Intraoperative C-arm cone-beam CT was performed under general anesthesia. Guidewire trajectory was planned using a needle guidance system. The guidewire was inserted along the overlaid trajectory using 3D fluoroscopic navigation, and a 6.5 mm cannulated cancellous screw (CCS) was placed. The clinical outcomes and accuracy of the screw placement were then investigated.ResultsA total of 121 screws were placed. The mean operative time was 84 ± 38.7 minutes, and the mean blood loss was 7.6 ± 3.8 g. The mean time to wheelchair transfer was 2 days postoperatively. Pain was relieved in 35 patients. Gait ability from preoperative and latest follow-up after surgery was maintained in 30 (73%) patients. All 41 patients achieved bone union. Of the 121 screws, 119 were grade 0 with no misplacement; only 2 patients had grade 1 perforations.ConclusionPPSP using real-time 3D fluoroscopic navigation in a hybrid operating room was accurate and useful for early mobilization and pain relief among older patients with FFP with an already-installed needle biopsy application.

Decompression of Thoracic Ossified Ligamentum Flavum with Floating Technique, Intraoperative Neurophysiological Monitoring and 3D Fluoroscopic Navigation

Ossification of ligamentum flavum (OLF) is a rare condition. A 62-year-old gentleman, with cord compression by thoracic OLF, was treated with laminectomy. In this paper, an unusual case of thoracic OLF treated by laminectomy with floating ossification, with the incorporation of intraoperative neurophysiological monitoring (IONM) and 3D fluoroscopic navigation, is presented and a review of the literature is described.

Comparison of novel machine vision spinal image guidance system with existing 3D fluoroscopy-based navigation system: a randomized prospective study

BACKGROUND CONTEXTThe use of spinal image guidance systems (IGS) has increased patient safety, accuracy, operative efficiency, and reduced revision rates in pedicle screw placement procedures. Traditional intraoperative 3D fluoroscopy or CT imaging produces potentially harmful ionizing radiation and increases operative time to register the patient. An IGS, FLASH Navigation, uses machine vision through high resolution stereoscopic cameras and structured visible light to build a 3D topographical map of the patient's bony surface anatomy enabling navigation use without ionizing radiation. PURPOSEWe aimed to compare FLASH navigation system to a widely used 3D fluoroscopic navigation (3D) platform by comparing radiation exposure and pedicle screw accuracy. DESIGNA randomized prospective comparative cohort study of consecutive patients undergoing open posterior lumbar instrumented fusion. PATIENT SAMPLEAdults diagnosed with spinal pathology requiring surgical treatment and planning for open posterior lumbar fusion with pedicle screws implanted into 1-4 vertebral levels. OUTCOME MEASURESOutcome measures included mean intraoperative fluoroscopy time and dose, mean CT dose length product (DLP) for preoperative and day 2 CT, pedicle screw accuracy by CT, estimated blood loss and revision surgery rate. METHODSConsecutive patients were randomized 1:1 to FLASH or 3D and underwent posterior lumbar instrumented fusion. Radiation doses were recorded from pre- and postoperative CT and intraoperative 3D fluoroscopy. 2 independent blinded radiologists reviewed pedicle screw accuracy on CT. RESULTSA total of 429 (n=210 FLASH, n=219 3D) pedicle screws were placed in 90 patients (n=45 FLASH, n=45 3D) over the 18-month study period. Mean age and indication for surgery were similar between both groups, with a non-significantly higher ratio of males in the 3D group.Mean intraoperative fluoroscopy time and doses were significantly reduced in FLASH compared to 3D (4.51±3.71s vs 79.6±23.0s, p<.001 and 80.9±68.1cGycm2 vs 3704.1±3442.4 cGycm2, p<.001, respectively). This represented a relative reduction of 94.3% in the total intraoperative radiation time and a 97.8% reduction in the total intraoperative radiation dose. Mean preoperative CT DLP and mean day 2 postoperative CT DLP were significantly reduced in FLASH compared to 3D (662.0±440.4mGy-cm vs 1008.9±616.3 mGy-cm, p<.001 and 577.9±294.3 mGy-cm vs 980.7±441.6 mGy-cm, p<.001, respectively). This represented relative reductions of 34.4% and 41.0% in the preoperative CT dose and postoperative total DLP, respectively.The FLASH group required an average of 1.2 registrations in each case with an average of 2447 (±961.3) data points registered with a mean registration time of 106s (±52.1). A rapid re-registration mechanism was utilized in 22% (n=10/45) of cases and took 22.7s (±11.3). Re-registration was used in 7% (n=3/45) in the 3D group.Pedicle screw accuracy was high in FLASH (98.1%) and 3D (97.3%) groups with no pedicle breach >2mm in either group (p<.001). EBL was not statistically different between the groups (p=.38). No neurovascular injuries occurred, and no patients required return to theatre for screw repositioning. CONCLUSIONSFLASH and 3D IGS demonstrate high accuracy for pedicle screw placement. FLASH showed significant reduction in intraoperative radiation time and dose with lower but non-significant blood loss. FLASH showed significant reduction in preoperative and postoperative radiation, but this may be associated to the lower number of males/females preponderance in this group. FLASH provides similar accuracy to contemporary IGS without requiring 3D-fluoroscopy or radiolucent operating tables. Reducing registration time and specialized equipment may reduce costs.

3D - Navigated percutaneous screw fixation of pelvic ring injuries – a pilot study

IntroductionScrew fixation of pelvic ring fractures is a common, but demanding procedure and navigation techniques were introduced to increase the precision of screw placement. The purpose of this case series is to demonstrate a lower screw malposition rate using percutaneous fixation of pelvic ring fractures and sacroiliac dislocations guided by navigation system based on 3D-fluoroscopic images compared to traditional imaging techniques and to evaluate the functional outcomes of this innovative procedure. Patient and Methods10 cases of disrupted pelvic ring lesions treated in our hospital from February 2018 to December 2018 were included for closed reduction and percutaneous screw fixation of using with O-Arm and the acquisition by the Navigator. Preoperative assessment was performed on the patients by means of X Ray imaging and CT scan. Routine CT was carried out on third postoperative day to evaluate screw placement. Measures of radiation exposure were extracted directly from reports provided by system. Quality of life was evaluated by SF 36-questionnaire 6 months after surgery. Results12 iliosacral- and 2 ramus pubic-screws were inserted. In post-operative CT-scans the screw position was assessed and graded using the score described by Smith. No wound infection or iatrogenic neurovascular damage were observed. No re-operations were performed. The exposure to radiation is, for the patient, slightly greater than that resulting from the use of traditional fluoroscopic systems, while it is naught for the surgical team, which at the time of image acquisition is located outside the room. Discussion and ConclusionThe execution of an intraoperative 3D-fluoroscopic scan can on its own suffice as a post-operative control examination since its accuracy is similar to that of the post-operative CT. The use of a navigated 3d fluoroscopy exposes the patient to an amount of radiation slightly greater than that of traditional fluoroscopy, but the dose is lower than a CT examination. For the operating team, exposure to radiation is naught. 3D-fluoroscopic navigation is a safe tool providing high accuracy of percutaneous screw placement for pelvic ring fractures. Finally, despite the small cohort of patients studied, the excellent results obtained regarding the patients' quality of life and the absence of complications allow us to look positively at the future of this technique, which needs further studies and improvement.

Factors influencing the accuracy of iliosacral screw insertion using 3D fluoroscopic navigation.

The purpose of the present study was to determine which factors affect the positional accuracy of iliosacral screws inserted using 3D fluoroscopic navigation. Specifically, we asked: (1) does the screw insertion angle in the coronal and axial planes affect the positional accuracy of iliosacral screw insertion using 3D fluoroscopic navigation? (2) Is the positional accuracy of iliosacral screw insertion using 3D fluoroscopic navigation affected by the type of screw (transsacral versus standard iliosacral), site of screw insertion (S1 versus S2), patient position (supine versus prone), presence of a dysmorphic sacrum, or AO/OTA classification (type B versus C)? Twenty-seven patients with AO/OTA type B or C pelvic ring fracture were treated by percutaneous iliosacral screw fixation. A total of 55 screws were inserted into S1 or S2 using 3D fluoroscopic navigation combined with preoperative CT-based planning. The positional accuracy of screw placement was assessed by matching postoperative CT images with preoperative CT images. The distance between the central axis of the inserted screw and that of the planned screw placement was measured in the sagittal plane passing through the center of the vertebral body. The mean deviation between the planned and the inserted screw position was 2.9 ± 1.7mm (range 0-8.5mm) at the vertebral body center. Multiple regression analysis showed that the screw insertion angle relative to the vertical line of the bone surface in the axial plane (β = 0.354, p = 0.013) and the use of a transsacral screw (β = 0.317, p = 0.017) were correlated with the positional accuracy of screw placement (adjusted R2 = 0.276, p = 0.002). A greater screw insertion angle relative to the vertical line on the bone surface and the use of transsacral screws increases the positional error of iliosacral screws inserted using 3D fluoroscopic navigation. Level IV, therapeutic study.

Clinical Application of Navigation in the Surgical Treatment of a Pelvic Ring Injury and Acetabular Fracture.

The purpose of this chapter is to review current evidence on indications, techniques, and outcomes of computer-navigated surgical treatment of pelvic ring injuries and acetabular fractures, particularly computer-navigated screw fixation.Iliosacral screw fixation of pelvic ring injury using navigation is attracting attention because the biomechanical stabilization of posterior pelvic ring disruption is of primary importance and is widely indicated because it does not require complete reduction of the fracture site. A cadaver study with a simulated zone II sacral fracture demonstrated a substantial compromise in the space available for iliosacral screws with displacements greater than 10 mm. It is possible to reduce the fracture fragment prior to intraoperative imaging in 2D or 3D fluoroscopic navigation. The use of 3D fluoroscopic navigation reportedly results in lower rates of iliosacral screw malpositioning than the use of the conventional technique or 2D fluoroscopic navigation. Moreover, compared with the conventional technique, it reduces radiation exposure and lowers revision rates. However, the malposition rate associated with 3D fluoroscopic navigation ranges from 0% to 31%, demonstrating that there is still room to improve the navigation performance.Conversely, complete articular surface reduction is required when treating a displaced acetabular fracture to prevent residual hip pain and subsequent osteoarthritic changes. Treating a severely displaced acetabular fracture by screw fixation is very challenging, even with the use of 3D fluoroscopic navigation, because of the difficulty in performing closed anatomical reduction. The indication for percutaneous screw fixation is limited to cases with a small articular displacement. Using 3D fluoroscopic navigation for open surgeries reportedly improves the quality of radiographic fracture reduction, limits the need for an extended approach, and lowers the complication rate.In conclusion, percutaneous screw fixation for pelvic ring injuries is widely indicated, and navigation makes these procedures safe and reliable. The indication for percutaneous screw fixation of acetabular fractures is limited to cases with a small articular displacement. Using 3D fluoroscopic navigation when performing open surgeries is reported to be useful in evaluating fracture reduction and screw position.

A New Electromagnetic Navigation System for Pedicle Screws Placement: A Human Cadaver Study at the Lumbar Spine

IntroductionTechnical developments for improving the safety and accuracy of pedicle screw placement play an increasingly important role in spine surgery. In addition to the standard techniques of free-hand placement and fluoroscopic navigation, the rate of complications is reduced by 3D fluoroscopy, cone-beam CT, intraoperative CT/MRI, and various other navigation techniques. Another important aspect that should be emphasized is the reduction of intraoperative radiation exposure for personnel and patient.The aim of this study was to investigate the accuracy of a new navigation system for the spine based on an electromagnetic field.Material and MethodTwenty pedicle screws were placed in the lumbar spine of human cadavers using EMF navigation. Navigation was based on data from a preoperative thin-slice CT scan. The cadavers were positioned on a special field generator and the system was matched using a patient tracker on the spinous process. Navigation was conducted using especially developed instruments that can be tracked in the electromagnetic field. Another thin-slice CT scan was made postoperatively to assess the result. The evaluation included the position of the screws in the direction of trajectory and any injury to the surrounding cortical bone. The results were classified in 5 groups: grade 1: ideal screw position in the center of the pedicle with no cortical bone injury; grade 2: acceptable screw position, cortical bone injury with cortical penetration ≤ 2 mm; grade 3: cortical bone injury with cortical penetration 2,1-4 mm, grad 4: cortical bone injury with cortical penetration 4,1-6 mm, grade 5: cortical bone injury with cortical penetration >6 mm.ResultsThe initial evaluation of the system showed good accuracy for the lumbar spine (65% grade 1, 20% grade 2, 15% grade 3, 0% grade 4, 0% grade 5). A comparison of the initial results with other navigation techniques in literature (CT navigation, 2D fluoroscopic navigation) shows that the accuracy of this system is comparable.ConclusionEMF navigation offers a high accuracy in Pedicle screw placement with additional advantages compared to other techniques. The short set-up time and easy handling of EMF navigation should be emphasized. Additional advantages are the absence of intraoperative radiation exposure for the operator and surgical team in the current set-up and the operator’s free mobility without interfering with navigation. Further studies with navigation at higher levels of the spine, larger numbers of cases and studies with control group are planned.

Iliosacral screw insertion using CT-3D-fluoroscopy matching navigation

BackgroundPercutaneous iliosacral screw insertion requires substantial experience and detailed anatomical knowledge to find the proper entry point and trajectory even with the use of a navigation system. Our hypothesis was that three-dimensional (3D) fluoroscopic navigation combined with a preoperative computed tomography (CT)-based plan could enable surgeons to perform safe and reliable iliosacral screw insertion. The purpose of the current study is two-fold: (1) to demonstrate the navigation accuracy for sacral fractures and sacroiliac dislocations on widely displaced cadaveric pelves; and (2) to report the technical and clinical aspects of percutaneous iliosacral screw insertion using the CT-3D-fluoroscopy matching navigation system. MethodsWe simulated three types of posterior pelvic ring disruptions with vertical displacements of 0, 1, 2 and 3cm using cadaveric pelvic rings. A total of six fiducial markers were fixed to the anterior surface of the sacrum. Target registration error over the sacrum was assessed with the fluoroscopic imaging centre on the second sacral vertebral body. Six patients with pelvic ring fractures underwent percutaneous iliosacral screw placement using the CT-3D-fluoroscopy matching navigation. Three pelvic ring fractures were classified as type B2 and three were classified as type C1 according to the AO-OTA classification. Iliosacral screws for the S1 and S2 vertebra were inserted. ResultsThe mean target registration error over the sacrum was 1.2mm (0.5–1.9mm) in the experimental study. Fracture type and amount of vertical displacement did not affect the target registration error. All 12 screws were positioned correctly in the clinical series. There were no postoperative complications including nerve palsy. The mean deviation between the planned and the inserted screw position was 2.5mm at the screw entry point, 1.8mm at the area around the nerve root tunnels and 2.2mm at the tip of the screw. ConclusionThe CT-3D-fluoroscopy matching navigation system was accurate and robust regardless of pelvic ring fracture type and fragment displacement. Percutaneous iliosacral screw insertion with the navigation system is clinically feasible.

The accuracy of pedicle screw placement using intraoperative image guidance systems

Several retrospective studies have demonstrated higher accuracy rates and increased safety for navigated pedicle screw placement than for free-hand techniques; however, the accuracy differences between navigation systems has not been extensively studied. In some instances, 3D fluoroscopic navigation methods have been reported to not be more accurate than 2D navigation methods for pedicle screw placement. The authors of this study endeavored to identify if 3D fluoroscopic navigation methods resulted in a higher placement accuracy of pedicle screws. A systematic analysis was conducted to examine pedicle screw insertion accuracy based on the use of 2D, 3D, and conventional fluoroscopic image guidance systems. A PubMed and MEDLINE database search was conducted to review the published literature that focused on the accuracy of pedicle screw placement using intraoperative, real-time fluoroscopic image guidance in spine fusion surgeries. The pedicle screw accuracy rates were segregated according to spinal level because each spinal region has individual anatomical and morphological variations. Descriptive statistics were used to compare the pedicle screw insertion accuracy rate differences among the navigation methods. A total of 30 studies were included in the analysis. The data were abstracted and analyzed for the following groups: 12 data sets that used conventional fluoroscopy, 8 data sets that used 2D fluoroscopic navigation, and 20 data sets that used 3D fluoroscopic navigation. These studies included 1973 patients in whom 9310 pedicle screws were inserted. With conventional fluoroscopy, 2532 of 3719 screws were inserted accurately (68.1% accuracy); with 2D fluoroscopic navigation, 1031 of 1223 screws were inserted accurately (84.3% accuracy); and with 3D fluoroscopic navigation, 4170 of 4368 screws were inserted accurately (95.5% accuracy). The accuracy rates when 3D was compared with 2D fluoroscopic navigation were also consistently higher throughout all individual spinal levels. Three-dimensional fluoroscopic image guidance systems demonstrated a significantly higher pedicle screw placement accuracy than conventional fluoroscopy or 2D fluoroscopic image guidance methods.

CT-3D-Fluoroscopy Matching Navigation Can Reduce the Malposition Rate of Iliosacral Screw Insertion for Less-Experienced Surgeons

The aim of the present study was to determine whether 3-dimensional (3D) fluoroscopic navigation combined with a preoperative computer tomography (CT)-based plan could enable surgeons to perform safe and reliable iliosacral screw insertion despite their limited experience. Eight pelvises with surrounding soft tissue donated from embalmed cadavers were used. Kirschner wires with a diameter of 3 mm were placed across the ilia bilaterally into the S1 and S2 vertebrae by 4 orthopaedic trainees. In 4 specimens, wires were placed across the right ilium using conventional technique and the left ilium using the CT-3D-fluoroscopy matching navigation system. In 4 other specimens, wires were placed across the right ilium using the 3D-fluoroscopic navigation system and the left ilium using the CT-3D-fluoroscopy matching navigation system. A postoperative CT-based analysis of wire localization was performed. The number of wire insertions until the final position check, operation duration, and radiation time and dose were also evaluated. The percentage of wires inserted correctly was higher in the CT-3D-fluoroscopy matching navigated group (100%) than in the conventional technique group (50%) and 3D-fluoroscopic navigation group (50%). The number of wire insertions and radiation time were significantly lower with both navigation systems than with the conventional technique, whereas there was no significant difference between the navigation systems. There were no significant differences in operation time and radiation dose among the 3 groups. The CT-3D-fluoroscopy matching navigation system reduced the malposition rate of percutaneous iliosacral screw insertion when performed by less experienced surgeons.

Clinical outcome of anatomic double-bundle ACL reconstruction and 3D CT model-based validation of femoral socket aperture position

The purpose of this study was to evaluate the clinical results of anatomic double-bundle (DB) anterior cruciate ligament (ACL) reconstruction in which anatomic position of femoral socket apertures was validated using three-dimensional (3D) computed tomography (CT) modelling. Anatomic DB ACL reconstructions with hamstring autografts were performed in 34 patients. Two femoral sockets were created through a far anteromedial (AM) portal behind the lateral intercondylar ridge with the assistance of intraoperative 3D fluoroscopic navigation. Femoral tunnel aperture positioning was investigated postoperatively using 3D CT images in all patients. Clinical results were also evaluated subjectively and objectively at least up to 2 years. Measurement of the AM and the posterolateral (PL) femoral socket locations on the 3D CT images using the quadrant method showed that the centre of the AM socket aperture was located at a depth of 21.0 ± 4.1% and a height of 30.5 ± 9.3% and that of the PL socket aperture was located at a depth of 31.3 ± 5.8% and a height of 57.2 ± 7.7%. The femoral socket locations were considered as anatomic in accordance with previous cadaveric studies examining the positions of ACL femoral insertion site. Subjectively, the mean Lysholm score was 96.9 ± 4.0 points. According to IKDC final objective scores, 26 knees (76%) were objectively graded as normal, 8 (24%) as nearly normal, and 0 (0%) as abnormal or severely abnormal. Postoperative side-to-side anterior translation measured with a KT-2000 arthrometer averaged 0.7 ± 1.2 mm. DB ACL reconstructions in which femoral socket apertures were validated anatomically using 3D CT provided satisfactory short-term results. Case series, Level IV.

An evaluation of three-dimensional image–guided technologies in percutaneous pelvic and acetabular lag screw placement

BackgroundPercutaneous stabilization using three-dimensional (3D) navigation system is a promising treatment for pelvic and acetabular fractures. However, there are still some controversies regarding the use of 3D navigation to treat pelvic and acetabular fractures. The purpose of this study was to compare the Iso-C3D fluoroscopic navigation, standard fluoroscopy, and two-dimensional (2D) fluoroscopic navigation in placing percutaneous lag screws in pelvic specimens to better understand the merits of 3D navigation techniques. MethodsFifty-four instrumentation procedures were performed in this study using six cadaveric pelvic specimens. Three groups were designated for different procedures and tests: group I, standard fluoroscopy; group II, 2D fluoroscopic navigation; and group III, Iso-C3D fluoroscopic navigation. Nine screws were placed in each pelvis, including four screws placed bilaterally through the ilium into S1 and S2 vertebrae, four screws placed bilaterally through anterior and posterior columns of acetabulum, and one screw placed through the pubic symphysis. 3D fluoroscopic techniques were evaluated to determine the accuracy of screw position, instrumentation time, and fluoroscopic time. The data were statistically analyzed using SPSS 13.0. ResultsThe malposition rate was 38.89%, 22.22%, and 0% in standard fluoroscopy, 2D fluoroscopic navigation, and Iso-C3D fluoroscopic navigation groups, respectively. There was no significant difference between standard fluoroscopy and 2D fluoroscopic navigation. Compared with Iso-C3D fluoroscopic navigation, there were significant differences (analysis of variance [ANOVA], P < 0.05). The mean instrumentation operating time using Iso-C3D fluoroscopic navigation technique was 15.4 ± 4.5 min. There were significant differences compared with standard fluoroscopy (31.5 ± 6.2 min) and 2D fluoroscopic navigation (26.3 ± 7.5 min; ANOVA, post hoc Scheffe, P < 0.01). The mean fluoroscopic time of Iso-C3D fluoroscopic navigation was 66 ± 4.8 min. Compared with standard fluoroscopy (132.8 ± 7.3 min) and 2D fluoroscopic navigation (47.7 ± 5.6 min), there were significant differences (ANOVA, post hoc least significant difference, P < 0.01). ConclusionsIn the present study, we compared Iso-C3D fluoroscopic navigation, 2D fluoroscopic navigation, and standard fluoroscopy. Iso-C3D fluoroscopic navigation showed a higher accuracy rate in positioning and a shorter instrumentation operating time. The fluoroscopic time was longer in Iso-C3D fluoroscopic navigation than that in standard fluoroscopy, indicating that radiation exposure can be moderately reduced in Iso-C3D fluoroscopic navigation operation, although the fluoroscopic time was the shortest in 2D fluoroscopic navigation.

Screw Placement for Acetabular Fractures

Screw navigation techniques with different image guidance [2-dimensional (2D) vs. 3-dimensional (3D) fluoroscopy] were evaluated for acetabular fracture surgery. Two-dimensional and 3D navigation images were analyzed for visualization of different osseous corridors: supra-acetabular, anterior column, posterior column, and infra-acetabular. Forty guide wires per group were placed in synthetic pelvis with a prefabricated soft tissue envelope (10 per group) using a 2D or 3D fluoroscopic navigation procedure. Duration of the single steps for each procedure and of cumulative fluoroscopy time was measured. The accuracy of guide wire placement was evaluated visually and in 3D cone-beam scans. The overall procedure time per pelvis was significantly reduced in the 3D group compared with the 2D group [mean ± standard error (SE) (minutes): 50.11 ± 1.38 vs. 63.42 ± 2.32; P < 0.0001]. A trend to reduction in image acquisition time [mean ± SE (minutes): 12.37 ± 1.34 vs. 15.43 ± 1.03; P = not significant] and significant increase in the cumulative fluoroscopy time [mean ± SE (seconds): 64 ± 9 vs. 13 ± 1.3; P < 0.0001) was measured in the 3D compared with the 2D group, caused by the 3D scan. Intra-articular misplacements were not observed in both the groups, but an increased accuracy could be achieved using the 3D image-based navigation procedure (perfect placement: 37 vs. 29; secure placement: 2 vs. 7; misplacement: 1 vs. 4). Both navigation procedures securely prevent an intra-articular penetration during drilling, but the 3D image-based navigation procedure increases the overall accuracy compared with the 2D image-based navigation technique (misplacement rates of 2.5% vs. 10%). Especially, in very narrow corridors (as the infra-acetabular screw path), the use of 3D navigation should be preferred.

Comparison of 2D and 3D navigation techniques for percutaneous screw insertion into the scaphoid: Results of an experimental cadaver study

Navigation in hand surgery is still in the process of development. Initial studies have demonstrated the feasibility of 2D and 3D navigation for the palmar approach in scaphoid fractures, but a comparison of the possibilities of 2D and 3D navigation for the dorsal approach is still lacking. The aim of the present work was to test navigation for the dorsal approach in the scaphoid using cadaver bones. After development of a special radiolucent resting splint for the dorsal approach, we performed 2D- and 3D-navigated scaphoid osteosynthesis in 12 fresh-frozen cadaver forearms using a headless compression screw (Synthes). The operation time, radiation time, number of trials for screw insertion, and screw positions were analyzed. In six 2D-navigated screw osteosyntheses, we found two false positions with an average radiation time of 5 ± 2 seconds. Using 3D navigation, we detected one false position. A false position indicates divergence from the ideal line of the axis of the scaphoid but without penetration of the cortex. The initial scan clearly increased overall radiation time in the 3D-navigated group, and for both navigation procedures operating time was longer than in our clinical experience without navigation. Nonetheless, 2D and 3D navigation for non-dislocated scaphoid fractures is feasible, and navigation might reduce the risk of choosing an incorrect screw length, thereby possibly avoiding injury to the subtending cortex. The 3D navigation is more difficult to interpret than 2D fluoroscopic navigation but shows greater precision. Overall, navigation is costly, and the moderate advantages it offers for osteosynthesis of scaphoid fractures must be considered critically in comparisons with conventional operating techniques.

Percutaneous screw fixation for the acetabular fracture with quadrilateral plate involved by three-dimensional fluoroscopy navigation: Surgical technique

BackgroundThe percutaneous three-dimensional (3D)-fluoroscopic-navigated screw directing to the quadrilateral plate was attempted. Materials and methodsFive patients with acetabular fractures were treated by 3D navigated percutaneous screw. The quadrilateral plate was involved in all the patients. The Arcadis 3D (ARCADIS Orbic 3D®; Siemens AG Healthcare Sector, Erlangen, Germany) and computer navigation system (stryker navigation system) were employed, screwing trajectory was attempted to anchor the quadrilateral plate perpendicularly to the fracture line and close to the joint cartilage as much as possible. Parameters including fracture gap closure (P1), distance to the joint cartilage (P2), angulations between the screw and the fracture line (P3), were measured with the software installed on the machine of Arcadis 3D. ResultSeven screws were inserted with the use of 3D fluoroscopic navigation. The quadrilateral plate was hold by percutaneous screws. The closure of fracture gap was achieved in 3 patients by 2–3mm. The nearest distance from the screw to the joint cartilage was ranged from <1mm to 6mm. The angulations between the screw and the fracture line was 80–90° in three patients, it was 60° and 65° respectively on the rest two patients. All patients felt pain free 1week after the operation. No complication was noted postoperatively. ConclusionThe surgical technique of percutaneous screwing for the acetabular fracture with three-dimensional fluoroscopy-based navigation was demonstrated.