Intraoperative Radiographs Research Articles

Is the axial spinal cord classification predictive of intraoperative neurologic alert for pediatric scoliosis patients? An independent retrospective validation study.

We sought to determine whether the axial spinal cord classification by Sielatycki et al. would be associated with increased intraoperative neuromonitoring (IONM) alerts for pediatric scoliosis patients undergoing posterior spinal fusion (PSF) surgery. Children less than age 19 with scoliosis undergoing PSF were retrospectively reviewed. Axial-T2 MRI of the thoracic apex was reviewed for spinal cord/CSF architecture as described by Sielatycki et al.: Type 1-circular cord with visible CSF, Type 2-circular cord but no visible CSF at apical concavity, and Type 3-cord deformed with no intervening CSF. Intraoperative neuromonitoring reports, operative records and preoperative radiographs were reviewed. 90 patients met the inclusion criteria. Rate of neurologic events was Type 1: 2% (1/41 patients), Type 2: 14.3% (4/28), Type 3: 57.1% (12/21) (Type 1 vs 2 p = 0.06; Type 1 vs 3 p < 0.0001; Type 2 vs 3 p = 0.0017). Three patients with a Type 3 cord awoke with significant deficits. In comparison to Type 1 cords, Type 3 and Type 2 spinal cords were associated with increased coronal and total deformity angular ratios (Type 1 vs 3 p = 0.035 and 0.0054 respectively; Type 1 vs 2 p = 0.042 and 0.03 respectively). There was no difference in gender, diagnosis category, age at surgery, Cobb angle or kyphosis between the three groups. The axial spinal cord classification correlated with IONM alerts and greater severity of spinal deformity in pediatric scoliosis patients. IV, retrospective cohort study.

Radiographic Reference Points Do Not Ensure Anatomic Femoral Fixation Sites in Medial Patellofemoral Ligament Reconstruction: A Quantified Anatomic Localization Method Based on the Saddle Sulcus

Background: Medial patellofemoral ligament (MPFL) reconstruction is one of the main treatments for lateral patellar translation. Based on intraoperative true lateral radiographs, the accepted methods for femoral MPFL tunnel location are potentially inaccurate. Direct assessment of anatomic characteristics during surgery through palpation of the anatomic landmarks involving the saddle sulcus might help eliminate tunnel malposition. Hypothesis: The saddle sulcus is a reliable osseous landmark where the MPFL attaches for tunnel placement. Study Design: Descriptive laboratory study. Methods: A total of 9 fresh-frozen unpaired human cadaveric knees were dissected; MPFL insertion point and relative osseous structures were marked. Three-dimensional images and transformed true lateral radiographs were obtained for analysis; 3 previously reported radiographic reference points for MPFL femoral tunnel placement were determined on all images and compared with the anatomic insertion. Results: A saddle sulcus consistently existed where the MPFL was attached, located at 11.7 ± 5.9 mm from the apex of the adductor tubercle (AT) to the medial epicondyle (ME), 62.8% of the average distance between the apexes of the AT and ME, and 5.6 ± 2.8 mm perpendicular-posterior to the border connecting the AT and ME. The reported radiographic reference points were located at average distances of 6.2 ± 3.2 mm (Schöttle method), 5.9 ± 2.3 mm (Redfern method), and 7.3 ± 6.6 mm (Fujino method) from the saddle sulcus center on the true lateral radiographs. Conclusion: The saddle sulcus was a reliable landmark where the MPFL was anatomically attached, located approximately 12 mm from the AT to the ME (approximately 60% along a line from the AT to the ME) and 6 mm perpendicular-posterior to the border connecting the apexes of the AT and ME. Additionally, the saddle sulcus position presented variability on the femoral aspect of different knees. All of the average direct distances from the sulcus to the reference radiographic points exceeded 5 mm, and tunnel localizations on a true lateral radiograph were inaccurate. Clinical Relevance: This study demonstrates the potential precise position of the saddle sulcus, according to the ME and AT, as a reliable anatomic landmark for MPFL femoral tunnel location. Radiographic reference points were not accurate during MPFL reconstruction. Direct palpation of the landmarks might be effective for femoral MPFL tunnel placement.

Radiographic Evaluation of Cervical Disk Replacement: The Impact of Preoperative Arthrosis and Implant Positioning on Patient-report Outcomes.

This was a retrospective review. Provide a validated method of radiographic evaluation of cervical disk replacement (CDR) patients linked to outcomes. Preoperative radiographic criteria for CDRs and the impact of intraoperative positioning remain without formalized guidelines. The association between preexisting degenerative changes, optimal implant positioning, and patient-reported outcome measures (PROMs) are not well understood. Our study establishes a systematic radiographic evaluation of preoperative spondylosis, implant placement, and associated clinical outcomes. Preoperative radiographs for CDR patients were evaluated for disk height, facet arthrosis, and uncovertebral joint degeneration. Postoperative radiographs were scored based on the position of the CDR implant on anterior-posterior (AP) and lateral radiographs. PROMs including Visual Analogue Scale (VAS) arm pain, VAS neck pain, Neck Disability Index (NDI), Short Form 12 physical health (SF12-PCS) and mental health (SF12-M) were collected preoperatively, at early follow, and at late follow-up. A total of 115 patients were included. Preoperative disk height had the highest reliability, intraclass correlation coefficient of 0.798). Facet arthrosis had the lowest intraclass correlation coefficient at 0.563. Preoperative disk height scores showed a significant correlation with AP radiographs and implant positioning score. Patients with more advanced uncovertebral degenerative changes showed less improvement 6 months postoperatively, based on SF-12 PCS scores (R=0.446, P=0.025). Postoperative implant position on lateral radiograph showed a significant correlation with SF-12 MCS scores at follow-up beyond 6 months (R=0.385, P=0.011). Overall postoperative implant position scores demonstrated significant correlation with SF-12 PCS (R=0.350, P=0.046) scores. This study provides a systematic method of evaluation of preoperative and intraoperative radiographs that can optimize outcomes. On the basis of our study, spine surgeons performing cervical disk replacement surgery should consider: (a) the presence of preexisting uncovertebral joint degeneration can negatively impact outcomes, (b) achieving optimal implant positioning can be increasingly difficult with more severe loss of disk height, and (c) overall implant position as judged on AP and lateral fluoroscopy can impact outcomes.

Using Online Survey Software to Enhance Radiology Learning

Online educational modules can augment radiology learning by creating opportunities to interact with images in more dynamic ways than with static presentation of images in lectures or journal articles. Building these modules on an online survey platform allows for quantitative assessment and learner feedback, without requiring programming knowledge or need for new website creation. Interactive online tutorials were built on a web-based survey platform (Qualtrics, Provo, Utah) accessible by computer or mobile device to teach radiology imaging findings of selected high-morbidity diagnoses. Topics included congenital-type internal hernias (module 1), acute appendicitis in the pregnant patient (module 2), and unintentionally retained surgical instruments (RSI; module 3). Modules consisted of pretest, educational module, and post-test components. For modules 1 and 2, graphics interchange formats were utilized to show CT and MRI image stacks for the diagnosis of congenital-type internal hernias and acute appendicitis in pregnant patients, respectively. For module 3, the "Heat Map" format was chosen to showcase intraoperative radiograph cases, which allowed participants to click on the potential RSI in the image. Pre- and post-test scores were evaluated. To determine statistical significance, an alpha level of 0.05 was utilized. Module 1 (Internal Hernia): Twenty-one radiology trainees completed the module. The mean pretest score was 3.66 (±1.13) points out of a total 6 possible points (61%), compared to 4.52 (±1.03) points on the post-test (75%). This was a statistically significant increase on the post-test of 0.87 points (95% CI [confidence interval] 0.36, 1.38), t(20) = 3.53, p= 0.002. Module 2 (MR Appendicitis): Seventeen radiology trainees completed the module. The mean pretest score was 3.18 (±1.42) points out of a total 6 possible points (53%), compared to 5.12 (±0.86) points on the post-test (85%). This was a statistically significant increase on the post-test of 1.94 points (95% CI 1.12, 2.76), t(16) = 5.00, p< 0.001. Module 3 (RSI): One hundred seven participants completed the module. The mean pretest score was 3.60 (±1.53) points out of a total 6 possible points (60%), compared to 4.54 (±1.36) points on the post-test (76%). This was a statistically significant increase on the post-test of 0.94 points (95% CI 0.67, 1.21), t(106) = 6.84, p< 0.001. An online survey platform can be used to build interactive education modules. Post-test scores significantly improved from pretest scores with these educational modules.

Radiologist Overreads of Intraoperative Radiographs—Value or Waste?

BackgroundAll aspects of the arthroplasty pathway must be scrutinized to maximize value and eliminate unnecessary cost. Radiology providers’ contracts with hospitals often call for readings of all radiographs. This policy has little effect on patient care when intraoperative radiographs are taken and used to make real-time decisions. In order to determine the value of radiologist overreads, we asked 3 questions: what was the delay between the time an intraoperative radiograph was taken and time the report was generated, were the overreads accurate, and what is the associated cost? MethodsTwo hundred hip and knee radiograph reports generated over 6 months during 391 cases were reviewed. The time the report was dictated was compared to the time taken and time of surgery completion. To determine accuracy, each overread was rated as accurate or inaccurate. The cost of the overread was determined by multiplying the number of radiographs times the radiology fee less the technical fee. ResultsMedian delay between taking the radiograph and filing the report was 45 minutes (range, 0-9778 minutes). Only 31.5% were filed before completion of the procedure. And 18.0% (36/200) were considered inaccurate despite lenient criteria. The reading fee for hip radiographs was $52.00, and for knee radiographs was $38.00, representing a total cost of $10,182 in our select series. This cost projects to $43,614 annually at our facility. ConclusionRadiology overreads of intraoperative radiographs have no effect on real-time decision-making. In the era of value-based care, payors should stop paying for overreads and reimburse providers who actually read the films intraoperatively.

P109. Improvements in screw placement and accuracy with newer generation robotic-assisted minimally invasive instrumented lumbar fusions

BACKGROUND CONTEXT Lumbar fusion techniques continue to evolve to improve patient safety, minimize soft tissue dissection, and increase the reliability and accuracy of pedicle screw placement. Early technical advancements included navigation and robotic assistance with minimally invasive approaches. Current generation robots now have a more robust and stable surgical arm and the ability to scan the entire surgical field to improve reliability and accuracy of pedicle screw placement. PURPOSE The purpose of this study is to determine if improvements from the earlier generation of surgical robots improve reliability and accuracy of pedicle screw placement. STUDY DESIGN/SETTING Comparative observational cohort. PATIENT SAMPLE A consecutive series of patients undergoing minimally invasive instrumented posterolateral fusion by a single surgeon using second generation (2ndGen) versus third generation (3rdGen) robotic guidance. OUTCOME MEASURES Number of screws planned, number of screws executed or abandoned, number of screws placed accurately. METHODS A consecutive series of patients undergoing minimally invasive instrumented posterolateral fusion by a single surgeon using second generation (2ndGen) versus third generation (3rdGen) robotic guidance were identified. Compared to the 2ndGen robot, the 3rdGen robot has a more robust robotic arm and scans the entire surgical field. The planning software remains the same. Data collected included demographics, total fluoroscopy time, number of planned screws, number of executed screws and number of screws executed accurately. Accurate screw placement was defined as screw placement in the planned position and trajectory without a need for repositioning and confirmed with intraoperative fluoroscopy and radiographs. RESULTS There were 70 cases in each group. The groups were comparable in terms of sex distribution, gender and body mass index. Even though there were more single-level cases in the 2ndGen (43, 61%) compared to the 3rdGen group (27, 39%, p=0.009); the mean total fluoroscopy time (58s vs 63s, p=0.739) and mean fluoroscopy time per level (46s vs 40s, p=0.399) were similar between the two groups. There was a statistically significantly higher rate of abandoned screw placements in the 2ndGen group compared to the 3rdGen group (p CONCLUSIONS Newer generation surgical robotic assistance, with a more robust and stable surgical arm and of the ability to scan the entire surgical field led to a lower rate of abandoned screw placements and greater screw accuracy compared to second generation robots. Further studies are needed to determine if these improvements in screw placement and accuracy translate to improved clinical outcomes. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

Differences in Re-excision Rates for Breast-Conserving Surgery Using Intraoperative 2D Versus 3D Tomosynthesis Specimen Radiograph

Intraoperative specimen radiographs performed during breast conservation surgery for cancer reduces the need for re-excision for positive margins. We studied 2D versus 3D image-guided cavity margin excision and compared it to final pathology and need for additional surgery. We conducted a retrospective review of 657 breast-conserving operations performed for cancer from 2013 to 2018. Procedures were performed by four surgeons at a single tertiary institution with access intraoperatively to 2D and 3D radiographs. Data collected included demographics, intraoperative margin assessment, final pathology, and re-excision rates. A total of 466 patients had 2D and 191 had 3D specimen imaging. The 2D group had a lower mean age and a higher body mass index and proportion of minority patients than the 3D group (P < 0.01). In the 3D group, there was a higher percentage of patients with mammographically denser breasts (P < 0.06); 58% of patients in the 3D group had additional imaging-directed cavity margins excised versus 32% of patients in the 2D group (P < 0.01). In the 2D group, 44 patients (9%) had positive final margins versus 8 patients (4%) in the 3D group (P = 0.02). No difference was found on total volume of excision (P = 0.56). The re-excision rate for the 2D group was 11% versus 5% for the 3D group (P = 0.02; adjusted odds ratio = 0.41, 95% confidence interval 0.19-0.86). Re-excision rates using both modalities are low. A lower re-excision rate is independently associated with 3D tomosynthesis. This allows surgeons to excise additional margins at the index operation, decreasing reoperations and anxiety/costs for patients.

The Reduction Maneuver for Pediatric Extension Type 3 Supracondylar Humerus Fractures.

Extension type supracondylar humerus fractures in children commonly displace in two directions: posteromedial and posterolateral. The traditional maneuver to reduce posteromedial displaced fractures utilizes pronation of the forearm, while the maneuver for posterolateral displaced fractures utilizes supination. Traditional teaching suggests that the periosteum is an aid to reduction. The purpose of this study is to take a second look at this periosteal hinge theory and reexamine the maneuver performed when reducing an extension type 3 supracondylar fracture. Sixty-nine consecutive displaced extension type 3 supracondylar fractures were studied. Intraoperative fluoroscopic radiographs were graded as posteromedial, posterolateral, or direct posterior displacement. All fractures were treated with closed reduction and percutaneous pinning. The best maneuver used to align the fracture during surgery was recorded in the operative note. The direction of displacement on radiographs was 32 (46.3%) posteromedial, 31 (45%) posterolateral, and six (8.7%) direct posterior. All of the 32 posteromedial displaced fractures were best aligned when pronation was utilized. All of the 31 posterolaterally displaced fractures were best aligned when supination was utilized. The six direct posteriorly displaced fractures obtained the best alignment in pronation. The current study reaffirms the classic teaching that the direction of displacement of the fracture indicates the site of the intact periosteum. The intact periosteal hinge can be used to obtain fracture reduction.

Multi-body 3D–2D registration for image-guided reduction of pelvic dislocation in orthopaedic trauma surgery

Surgical reduction of pelvic dislocation is a challenging procedure with poor long-term prognosis if reduction does not accurately restore natural morphology. The procedure often requires long fluoroscopic exposure times and trial-and-error to achieve accurate reduction. We report a method to automatically compute the target pose of dislocated bones in preoperative CT and provide 3D guidance of reduction using routine 2D fluoroscopy. A pelvic statistical shape model (SSM) and a statistical pose model (SPM) were formed from an atlas of 40 pelvic CT images. Multi-body bone segmentation was achieved by mapping the SSM to a preoperative CT via an active shape model. The target reduction pose for the dislocated bone is estimated by fitting the poses of undislocated bones to the SPM. Intraoperatively, multiple bones are registered to fluoroscopy images via 3D–2D registration to obtain 3D pose estimates from 2D images. The method was examined in three studies: (1) a simulation study of 40 CT images simulating a range of dislocation patterns; (2) a pelvic phantom study with controlled dislocation of the left innominate bone; (3) a clinical case study investigating feasibility in images acquired during pelvic reduction surgery. Experiments investigated the accuracy of registration as a function of initialization error (capture range), image quality (radiation dose and image noise), and field of view (FOV) size. The simulation study achieved target pose estimation with translational error of median 2.3 mm (1.4 mm interquartile range, IQR) and rotational error of 2.1° (1.3° IQR). 3D–2D registration yielded 0.3 mm (0.2 mm IQR) in-plane and 0.3 mm (0.2 mm IQR) out-of-plane translational error, with in-plane capture range of ±50 mm and out-of-plane capture range of ±120 mm. The phantom study demonstrated 3D–2D target registration error of 2.5 mm (1.5 mm IQR), and the method was robust over a large dose range, down to 5 Gy/frame (an order of magnitude lower than the nominal fluoroscopic dose). The clinical feasibility study demonstrated accurate registration with both preoperative and intraoperative radiographs, yielding 3.1 mm (1.0 mm IQR) projection distance error with robust performance for FOV ranging from 340 × 340 mm2 to 170 × 170 mm2 (at the image plane). The method demonstrated accurate estimation of the target reduction pose in simulation, phantom, and a clinical feasibility study for a broad range of dislocation patterns, initialization error, dose levels, and FOV size. The system provides a novel means of guidance and assessment of pelvic reduction from routinely acquired preoperative CT and intraoperative fluoroscopy. The method has the potential to reduce radiation dose by minimizing trial-and-error and to improve outcomes by guiding more accurate reduction of joint dislocations.

Digitalized analyses of intraoperative acetabular component position using image-matching technique in total hip arthroplasty.

AimsAppropriate acetabular component placement has been proposed for prevention of postoperative dislocation in total hip arthroplasty (THA). Manual placements often cause outliers in spite of attempts to insert the component within the intended safe zone; therefore, some surgeons routinely evaluate intraoperative pelvic radiographs to exclude excessive acetabular component malposition. However, their evaluation is often ambiguous in case of the tilted or rotated pelvic position. The purpose of this study was to develop the computational analysis to digitalize the acetabular component orientation regardless of the pelvic tilt or rotation.MethodsIntraoperative pelvic radiographs of 50 patients who underwent THA were collected retrospectively. The 3D pelvic bone model and the acetabular component were image-matched to the intraoperative pelvic radiograph. The radiological anteversion (RA) and radiological inclination (RI) of the acetabular component were calculated and those measurement errors from the postoperative CT data were compared relative to those of the 2D measurements. In addition, the intra- and interobserver differences of the image-matching analysis were evaluated.ResultsMean measurement errors of the image-matching analyses were significantly small (2.5° (SD 1.4°) and 0.1° (SD 0.9°) in the RA and RI, respectively) relative to those of the 2D measurements. Intra- and interobserver differences were similarly small from the clinical perspective.ConclusionWe have developed a computational analysis of acetabular component orientation using an image-matching technique with small measurement errors compared to visual evaluations regardless of the pelvic tilt or rotation.Cite this article: Bone Joint Res 2020;9(7):360–367.

Is the Fibular Station on Lateral Ankle Radiographs Symmetric? A Retrospective Observational Radiographic Study.

Precise reduction of a syndesmosis after disruption is critical to improve patient physical function. Intraoperative lateral radiographs of the unaffected ankle are often used in clinical practice as a template for anatomic syndesmotic reduction because sagittal plane malreduction is common. However, there is little data to suggest fibular station, or the position of the fibula in the AP plane on the lateral radiograph, is symmetric side-to-side in patients. (1) Is the position of the fibula in the AP plane (fibular station) on lateral ankle radiographs symmetric in an individual? (2) Do the measurements used to judge the position of the fibula on lateral radiographs have good inter- and intraobserver reliability? Over the period from August 2016 to October 2018, we identified 478 patients who presented to an orthopaedic clinic with forefoot and midfoot complaints. Skeletally mature patients with acceptable bilateral lateral ankle radiographs, which are common radiographs obtained for new patients to clinic for any complaint, were included. Based on that, 52% (247 of 478 patients) were included with most (22%, 107 patients) excluded for poor lateral radiographs. The most common diagnosis in the patient cohort was midfoot OA (14%, 35 patients). The median (range) age of the included patients was 54 years (15 to 88), and 65% (159 of 247) of the patients were female. Fibular station, defined as the position of the fibula in the AP plane, and fibular length were measured using a digital ruler and goniometer on lateral radiographs. A paired t-test was used to determine if no difference in fibular station existed between the left and right ankles. With 247 paired-samples, with 80% power and an alpha level of 0.05, we could detect a difference between sides of 0.008 for the posterior ratio, 0.010 for the anterior ratio, and 0.012 for fibular length. Two readers, one fellowship-trained orthopaedic traumatologist and one PGY-4, measured 40 patients to determine the inter- and intraobserver reliability by intraclass correlation coefficient (ICC). The posterior fibular station (mean right 0.147 [σ = 0.056], left 0.145 [σ = 0.054], difference = 0.03 [95% CI 0 to 0.06]; p = 0.59), anterior fibular station (right 0.294 [σ = 0.062], left 0.299 [σ = 0.061], difference = 0.04 [95% CI 0 to 0.08]; p = 0.20), and fibular length (right 0.521 [σ = 0.080], left 0.522 [σ = 0.078], difference = 0.05 [95% CI 0.01 to 0.09]; p = 0.87) ratios did not differ with the numbers available between ankles. Inter- and intraobserver reliability were excellent for the posterior ratio (ICC = 0.928 and ICC = 0.985, respectively) and the anterior ratio (ICC = 0.922 and ICC = 0.929, respectively) and moderate-to-good for the fibular length ratio (ICC = 0.732 and ICC = 0.887, respectively). The use of lateral radiographs of the contralateral uninjured ankle appears to be a valid template for determining the position of the fibula in the sagittal plane. However, further prospective studies are required to determine the efficacy of this method in reducing the syndesmosis over other methods that exists. Level III, diagnostic study.

Advantages of intraoperative digital specimen radiography (IDSR) in breast surgery.

e12613 Background: Breast cancer is in first place among malignant diseases in women in Russia. We can provide, in most cases, breast-conserving surgery (BCS), due to progress in early diagnosis. Evaluation of positive margins is still one of the most important objectives in breast-conserving surgery. Objectives: To assess the benefits of IDSR in BCS of patients with “carcinoma in situ”. Methods: The results of treatment of 55 patients with breast cancer “carcinoma in situ” in our clinic were evaluated in two comparable groups. Group A included 28 patients, who were operated on from January 2019 to June 2019 and had breast-conserving surgery without IDSR. Group B included 27 patients, who were operated on from June 2019 to January 2020 and had breast-conserving surgery with the evaluation of margins by IDSR. Results: In a planned histological examination positive margins were detected in group A in 4 cases (14%) and required reoperation. In group B all margins were clear. After IDSR, 6 (22%) patients out of 27 in this group showed microcalcifications in the resection margins or at a distance of less than 1 mm and required intraoperative additional excision to obtain clean margins. Conclusions: IDSR reduces the frequency of reoperation due to increased detection of positive margins, allows to correct scope and duration of surgery because of impact on the time of the surgical decision-making process.

Analysis of Implant Related Complications following Proximal Femoral Nail Anirotation (PFNA) fixation in Unstable Intertrochanteric fractures - early follow up

INTRODUCTION; Intertrochanteric fractures present in a wide variety of patterns that range from simple to complex and may be minimally displaced or widely displaced. Unstable intertrochanteric fracture can fail due to mechanical problems, including loss of fixation, re-fracture, or implant failure. PURPOSE; The aim of this study was to analyse the failures in patients with unstable intertrochanteric femur fractures treated with short Proximal Femoral Nail Antirotation (Synthes) METHODS; A retrospective analysis of 97 patients with unstable intertrochanteric factures (AO : 31A2, n = 65 / 67.01 % ; 31-A3: n = 32 /32.9 %) treated with a PFNA in a self-contained district general hospital was conducted. RESULTS; The study included 25 (26%) males and 72 (74%) females with mean age of 82 years. The study period was over 12 months with mean follow up of 11 months (range 6 to 18 months). Intraoperative and postoperative radiographs showed good reduction in 80 patients, acceptable in 12 and poor in 3. Twenty patients had implant related complications, consequently ten patients (10.5 %) had to undergo revision surgery. The reasons of revision surgery were; Implant failures = 8 (8.4%), Helical Blade backing out =1( 1.05 %) and Greater trochanter splintering =1 (1.05%). CONCLUSION ; Implant related complications requiring revision occurred in 10 patients (10.5 %) in early follow up. Of those requiring revision 6 patients had highly unstable 31 A2.3 type fracture. Our study reinforces high failures in unstable intertrochantric fractures. Though Ideal implant remains elusive but Optimum intraoperative reduction and use of augments should be considered to improve outcomes.

Cannulated Screw Fixation of Femoral Neck Fractures: An Intraoperative Pearl to Avoid a Common Mistake

Percutaneous cannulated screw fixation is a well-described and relatively successful technique aimed at addressing femoral neck fractures. The advantages of this technique are limited primarily to its small surgical footprint and ability to preserve native femoral neck bone stock. Although the “3-point principle” described by Bout and colleagues aims at minimizing the potential complications and modes of mechanical failure of this fixation technique, the new literature suggests that our intraoperative radiographs may not be as reliable at detecting erroneous screw position as we may think. Hoffmann and colleagues recently demonstrated through a cadaveric study that 70% of the cranial-posterior screw in the “inverted triangle” construct, which were deemed cortically contained on fluoroscopy, actually breached the cortex. Although the clinical ramifications of this technical error are not fully understood, there is undoubtedly concern surrounding the biomechanical impact of altering the femoral neck’s ability to resist tension while upright and compression while seated because of the location of this breach. This article aims to provide a technical pearl for accurately placing screws to abut the femoral neck cortex while avoiding cortical breach in the “inverted triangle” fixation construct.

Image-Guided Robotic K-Wire Placement for Orthopaedic Trauma Surgery.

We report the initial development of an image-based solution for robotic assistance of pelvic fracture fixation. The approach uses intraoperative radiographs, preoperative CT, and an end effector of known design to align the robot with target trajectories in CT. The method extends previous work to solve the robot-to-patient registration from a single radiographic view (without C-arm rotation) and addresses the workflow challenges associated with integrating robotic assistance in orthopaedic trauma surgery in a form that could be broadly applicable to isocentric or non-isocentric C-arms. The proposed method uses 3D-2D known-component registration to localize a robot end effector with respect to the patient by: (1) exploiting the extended size and complex features of pelvic anatomy to register the patient; and (2) capturing multiple end effector poses using precise robotic manipulation. These transformations, along with an offline hand-eye calibration of the end effector, are used to calculate target robot poses that align the end effector with planned trajectories in the patient CT. Geometric accuracy of the registrations was independently evaluated for the patient and the robot in phantom studies. The resulting translational difference between the ground truth and patient registrations of a pelvis phantom using a single (AP) view was 1.3 mm, compared to 0.4 mm using dual (AP+Lat) views. Registration of the robot in air (i.e., no background anatomy) with five unique end effector poses achieved mean translational difference ~1.4 mm for K-wire placement in the pelvis, comparable to tracker-based margins of error (commonly ~2 mm). The proposed approach is feasible based on the accuracy of the patient and robot registrations and is a preliminary step in developing an image-guided robotic guidance system that more naturally fits the workflow of fluoroscopically guided orthopaedic trauma surgery. Future work will involve end-to-end development of the proposed guidance system and assessment of the system with delivery of K-wires in cadaver studies.

Simulation of scattered radiation during intraoperative imaging in a virtual reality learning environment.

Scattered radiation, which occurs when using a C-arm for intraoperative radiography, can be better understood through interactive visualization. We developed a virtual reality (VR) approach for the simulation of scattered radiation (SSR) as part of a C-arm training system. In VR, it is important to avoid cyber sickness, which is often caused by increased latency between head motion and image presentation inside the head-mounted display. As the latency requirement interferes with the computational complexity of the SSR, the goal has been to maintain a low latency during the simultaneous computation of the SSR on moderate-cost consumer hardware. For use with a VR C-arm simulator, a CUDA-based Monte Carlo SSR has been improved to utilize GPU resources unused by the VR image generation. Resulting SSR data are visualized through volume rendering with pseudo-colored scattered radiation superimposed onto the virtual operating room. The resulting interactive VR-SSR environment was evaluated with operating room personnel (ORP) and surgeons using questionnaires. Depending on the imaged body part and computation parameters, the required computation time to complete one SSR run was between 1.6 and 4.2s (ankle) and between 7.9 and 14.9s (thigh), and VR frame times from 11 to 12ms (95th percentile). The system was evaluated with ORP (n = 46) and surgeons (n = 25). The median of professional C-arm experience was 5 (range 1 to 34) years (ORP) and 12.5 (range 2 to 48) years (surgeons), respectively. The demonstrated prototype was found useful by 78% of ORP and 88% of the surgeons. On a Likert scale, more than 90% of both groups "agreed fully" that the presented way of visualizing SSR in VR helps understanding intraoperative exposure to scattered radiation. Leveraging off-the-shelf computer equipment, the feasibility of SSR and VR for interactive training has been demonstrated. Evaluation participants showed a high interest for the presented approach. Feedback suggests that the visualization experienced by the users helps understanding radiation hazards in the operating room.

Abstract P1-01-05: Intraoperative three-dimensions MiniiSCANR for determine adequate margin in breast cancer specimens before histopathological examination

Abstract Background: 20-30% of breast conserving surgery patients undergo a second re-excision procedure due to tumor-positive margins at final histopathology. Various modalities are used to assess the adequacy of surgical resection to minimize positive margin and reoperation rates. MiniiSCAN™ is a method of intraoperative specimen radiography that allows for margin evaluation following excisional breast lesion either BI-RADS 4 and 5. The mechanism of MiniiSCAN™ is similar to computer tomography but specimen is rotated on the plate instead circular rotating frame with an x-ray tube mounted on 1 side and a detector on the opposite side in conventional computerized tomography scan. It is easily and short time to reconstructed into 3 dimensions. This machine was developed by Songklanagarind hospital and National Science and Technology Development Agency, Thailand. Objective: To evaluate the efficacy of MiniiSCAN™ as a surgical margin guidance tool compared with pathological margin in breast cancer specimens. Materials &amp; Methods: A retrospective review was designed, 62 consecutive cases of abnormal mammogram (BI-RADS 4,5) with or without wire localization from 1 June 2016 to 30 June 2019 were identified from the electronic medical records at Prince of Songkla University. Results: Of the 62 specimens imaged, 17 had invasive cancer and ten had in-situ pathological diagnoses. Of these, 10 patients had a positive tumor margin and 17 a negative tumor margin at final histopathology. Margin status evaluation by MiniiSCAN™ reconstruction were calculated in 4 minutes (acquisition and reconstruction time). Of the 27 specimens readings, the margin status in 24 patients was correctly predicted by MiniiSCAN™. There were two false-negative predictions. The accuracy, sensitivity, specificity, positive predictive value and negative predictive value of MiniiSCAN™ in margin status prediction were 88.89%, 80%, 94.11%, 88.89% and 88.89%, respectively. Conclusion: MiniiSCAN™ could be integrated into routine care, enabling the surgical team to perform and interpret specimen radiographs rapidly and make immediate surgical decisions. Keywords: Abnormal mammography, Breast cancer, CT scan, Specimen radiography Citation Format: Suphawat Laohawiriyakamol, Piyanun Wangkulankul, Piyanoot Woodtichartpreecha, Puttisak Puttawibul. Intraoperative three-dimensions MiniiSCANR for determine adequate margin in breast cancer specimens before histopathological examination [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P1-01-05.

Intraoperative Radiography to Aid in Biopsy Clip Retrieval at the Time of Surgery.

Intraoperative Radiography to Aid in Biopsy Clip Retrieval at the Time of Surgery.

A new method for intraoperative assessment of leg length, sizing and placement of the components in total hip replacement.

Intraoperative radiograph of the pelvis is a well-established way to avoid misplacement/undersizing of the components and leg length discrepancy (LLD) in total hip replacement (THR). We describe a method for the obtainment and the evaluation of intraoperative radiographs with a sophisticated wireless radiographic system and a computerized digital tool originally used for preoperative templating. In this retrospective case-control study, 60 patients with unilateral hip osteoarthritis who underwent THR with intraoperative radiographic check with the conventional method (n = 30, control group) or the new method (AGFA flat panel DR14eG™/Orthosize™, n = 30, case group) were evaluated and compared for operation time, intraoperative changes in size/placement of the components and final radiological outcome (LLD, acetabular inclination and femoral offset) based on postoperative radiographs of the pelvis. Mean operation time was lower in case group (85.3min vs. 103.3min, p value < 0.005), as well as mean absolute LLD (1.93mm vs. 2.94mm, p value = 0.242). There was a higher percentage of intraoperative changes in the offset of the prostheses' head (70% vs. 40%, p value = 0.018) and a significantly lower percentage of patients with LLD > 5mm in the case group (0% vs. 27%, p value = 0.002). This new method for the obtainment and assessment of intraoperative radiographs proved to be fast and assuring for keeping LLD below 5mm in all patients.

Implant-Related Complications Following Proximal Femoral Nail Antirotation (PFNA) in Unstable Intertrochanteric Fractures – Early Follow Up

INTRODUCTION; Intertrochanteric fractures present in a wide variety of patterns that range from simple to complex and may be minimally displaced or widely displaced. Unstable intertrochanteric fracture can fail due to mechanical problems, including loss of fixation, re-fracture, or implant failure. PURPOSE; The aim of this study was to analyse the failures in patients with unstable intertrochanteric femur fractures treated with short Proximal Femoral Nail Antirotation (Synthes) METHODS; A retrospective analysis of 97 patients with unstable intertrochanteric factures (AO : 31A2, n = 65 / 67.01 % ; 31-A3: n = 32 /32.9 %) treated with a PFNA in a self-contained district general hospital was conducted. RESULTS; The study included 25 (26%) males and 72 (74%) females with mean age of 82 years. The study period was over 12 months with mean follow up of 11 months (range 6 to 18 months). Intraoperative and postoperative radiographs showed good reduction in 80 patients, acceptable in 12 and poor in 3. Twenty patients had implant related complications, consequently ten patients (10.5 %) had to undergo revision surgery. The reasons of revision surgery were; Implant failures = 8 (8.4%), Helical Blade backing out =1( 1.05 %) and Greater trochanter splintering =1 (1.05%). CONCLUSION ; Implant related complications requiring revision occurred in 10 patients (10.5 %) in early follow up. Of those requiring revision 6 patients had highly unstable 31 A2.3 type fracture. Our study reinforces high failures in unstable intertrochantric fractures. Though Ideal implant remains elusive but Optimum intraoperative reduction and use of augments should be considered to improve outcomes.