Intraoperative Cone-beam CT Research Articles

New hybrid multiplanar cone beam computed tomography-laser-fluoroscopic-guided approach in cochlear implant surgery

PurposeCochlea implant surgery with proper positioning of the cochlear electrode can be challenging. Intraoperative real-time hybrid laser-fluoroscopic-guided navigation based on a multiplanar cone beam computed tomography (CBCT) dataset opens up the opportunity to immediate radiological control of primary electrode misalignments and offering new insights into the cochlea electrode insertion routes and favorable cochlear implant-insertion angle.MethodsIn this retrospective study, 50 cases (29 males, 18 females) of conventional electrode implantation (without intraoperative image control; group A) and nine cases (7 males, 2 females) of CBCT-laser-fluoroscopic-guided surgery (group B) were included in the present study. CBCT-laser-guided surgery under real-time fluoroscopic control was conducted using an intraoperative C-arm CBCT. All patients received preoperative cross-sectional imaging (CT and MRI), in which cochlear malformation could be excluded. Postoperatively, we looked for electrode misplacements.ResultsIn group A, electrode misalignment was detected postoperatively in 14 of 50 cases (28.0%). In group B, primary electrode misalignment was detected intraoperatively in two patients (22.2%). In both patients, the misalignments were corrected in the same session. The comparison of cochlear insertion angles showed significant differences. Group A: 47.5 ± 2.6° (actual conventional surgery) vs 17.6 ± 2.8° (theoretical CBCT-laser-fluoroscopic-guided surgery) P < 0.001. Group A vs group B: 47.5 ± 2.6° (actual conventional surgery; Group A) vs 17.9 ± 2.5° (actual CBCT-laser-fluoroscopic-guided surgery; Group B) P < 0.001.ConclusionWe consider that an intraoperative hybrid CBCT-laser-fluoroscopic-controlled approach in cochlear implant surgery using a C-arm CT can be beneficial, because electrode misalignments can be reduced and if it does occur, remedied in the same surgical session.

MRI-based and robot-assisted stereotactic biopsy with intraoperative CT imaging.

As a pioneer center in the field of stereotaxy, Sainte-Anne school has always advocated the use of intraoperative imaging for stereotactic procedures to optimize both safety and accuracy. With the advent of intraoperative mobile CT unit, the robot-assisted stereotactic biopsy procedure has been recently updated. Herein, we aim at describing our new surgical procedure that combines robotic assistance (NeuroMate, Renishaw) and intraoperative cone beam CT imaging (O-Arm, Medtronic). Intraoperative imaging with the O-Arm was efficiently incorporated into the workflow. This new equipment leads to optimizing operative time and an easier realization of intraoperative imaging.

Intraoperative computed tomography imaging for laryngoplasty

ObjectivesIntraoperative cone beam computed tomography (CBCT) imaging has the potential to facilitate the surgical procedure. The current preliminary retrospective chart review investigated the benefits of intraoperative CBCT during laryngoplasty. MethodThis study examined 26 cases that underwent intraoperative CBCT imaging during laryngoplasty, with one patient who counted twice due to first and revision surgery. The visual quality of structures of interest (glottal shape, thyroid cartilage, arytenoid cartilage, and implants) was determined using intraoperative CBCT during laryngoplasty. Each patient also underwent an aerodynamic assessment. ResultsCBCT provided unique information, such as surgical landmarks in severe scarring, the subglottal shape, and the rotation angle of the arytenoid cartilage during arytenoid adduction. Nonetheless, 26.9% (7 of 26) of cases were affected by motion artifact, due to the long acquisition time. When motion artifact-negative cases were evaluated, 100% of glottal shape and more than 89% of thyroid cartilage were well visualized. All arytenoids were well-visualized in patients ≥ 50 years of age and without motion artifact, while CBCT failed to visualize the arytenoids in 2 of 4 patients who were < 50 years, due to the lack of calcifications. After medialization surgery, the yields of improved maximal phonation times (MPTs) in the motion artifact-negative and -positive groups were 8.7 sec and 3.4 sec, respectively (p = 0.032; Welch's t test). This comparison indicates intraoperative CBCT would contribute in MPT improvement, if CBCT is taken in measurable quality. ConclusionThe potential benefits of intraoperative CBCT during laryngoplasty were demonstrated. A corollary, prospective study is warranted to further confirmation.

The use of a novel short dilator tip on the distal bifurcated component during fenestrated aortic repair to avoid reno-visceral bridging stents.

The aim of this study was to evaluate the feasibility and efficacy of a modified delivery system of the distal bifurcated FEVAR component where the dilator tip was shortened to prevent damage to the renovisceral bridging stents. All consecutive patients from a tertiary referral center that underwent a FEVAR with a custom delivery system of the distal bifurcated endograft with a short tip between November 2017 and July 2019 were retrospectively analyzed. Only patients with complete fluoroscopic loops of the insertion and deployment of the distal endograft were included. The primary study endpoint was the degree of crossing of the fenestration bridging stent-grafts, that was graded as 'not crossing', 'partial crossing' and 'complete crossing' relative to the lowermost placed fenestration. Secondary endpoints included fenestration related adverse events, secondary interventions, changes in renal function, aneurysm related mortality and overall mortality. 23 patients were included (21 (91%) juxta-renal aneurysms, 2 TAAA type IV (9%). The lowermost fenestration was crossed in 4 (17.3%), partially crossed in 9 (39.1%) and not crossed in 10 (43.4%) cases. Partial compression or inadequate flaring of a fenestration stent-graft was identified in the intraoperative cone beam CT in 6 (26.0%) patients and corrected peri-operatively. Technical success was 100%. Median follow-up was 34 (27-38) months with two non-aneurysm related deaths during this period. Four patients (17.3%) underwent a secondary intervention related to a fenestration bridging stent-graft. The use of a custom short dilator introducer tip on the bifurcated device during FEVAR reduces the need to cross the fenestration bridging stent-grafts and may result in less fenestration related adverse events. However, the reno-visceral segment is still frequently crossed by the iliac extension which may lead to adverse events. This could likely be avoided by a similar adaptation on the iliac extension delivery system.

Extended Intraoperative Longitudinal 3-Dimensional Cone Beam Computed Tomography Imaging With a Continuous Multi-Turn Reverse Helical Scan.

Cone beam computed tomography (CBCT) imaging is becoming an indispensable intraoperative tool; however, the current field of view prevents visualization of long anatomical sites, limiting clinical utility. Here, we demonstrate the longitudinal extension of the intraoperative CBCT field of view using a multi-turn reverse helical scan and assess potential clinical utility in interventional procedures. A fixed-room robotic CBCT imaging system, with additional real-time control, was used to implement a multi-turn reverse helical scan. The scan consists of C-arm rotation, through a series of clockwise and anticlockwise rotations, combined with simultaneous programmed table translation. The motion properties and geometric accuracy of the multi-turn reverse helical imaging trajectory were examined using a simple geometric phantom. To assess potential clinical utility, a pedicle screw posterior fixation procedure in the thoracic spine from T1 to T12 was performed on an ovine cadaver. The multi-turn reverse helical scan was used to provide postoperative assessment of the screw insertion via cortical breach grading and mean screw angle error measurements (axial and sagittal) from 2 observers. For all screw angle measurements, the intraclass correlation coefficient was calculated to determine observer reliability. The multi-turn reverse helical scans took 100 seconds to complete and increased the longitudinal coverage by 370% from 17 cm to 80 cm. Geometric accuracy was examined by comparing the measured to actual dimensions (0.2 ± 0.1 mm) and angles (0.2 ± 0.1 degrees) of a simple geometric phantom, indicating that the multi-turn reverse helical scan provided submillimeter and degree accuracy with no distortion. During the pedicle screw procedure in an ovine cadaver, the multi-turn reverse helical scan identified 4 cortical breaches, confirmed via the postoperative CT scan. Directly comparing the screw insertion angles (n = 22) measured in the postoperative multi-turn reverse helical and CT scans revealed an average difference of 3.3 ± 2.6 degrees in axial angle and 1.9 ± 1.5 degrees in the sagittal angle from 2 expert observers. The intraclass correlation coefficient was above 0.900 for all measurements (axial and sagittal) across all scan types (conventional CT, multi-turn reverse helical, and conventional CBCT), indicating excellent reliability between observers. Extended longitudinal field-of-view intraoperative 3-dimensional imaging with a multi-turn reverse helical scan is feasible on a clinical robotic CBCT imaging system, enabling long anatomical sites to be visualized in a single image, including in the presence of metal hardware.

Non-circular CBCT orbit design and realization on a clinical robotic C-arm for metal artifact reduction.

Metal artifacts have been a difficult challenge for cone-beam CT (CBCT), especially for intraoperative imaging. Metal surgical tools and implants are often present in the field of view and can attenuate X-rays so heavily that they essentially create a missing-data problem. Recently, an increasing number of intra-operative imaging systems such as robotic C-arms are capable of non-circular orbits for data acquisition. Such trajectories can potentially improve sampling and the degree of data completeness to solve the metal-induced missing-data problem, thereby reducing or eliminating the associated image artifacts. In this work, we extend our prior theoretical and experimental work and implement non-circular orbits for metal artifact reduction on a clinical robotic C-arm (Siemens Artis zeego). To maximize the potential for clinical translation, we restrict our implementation to standard built-in motion and data collection functions, also available on other zeego systems, and work within the physical constraints and limitations on positioning and motion. Customized software tools for data extraction, processing, calibration, and reconstruction are used. We demonstrate example non-circular orbits and the resulting image quality using a phantom containing pedicle screws for spine fixation. As compared with a standard circular CBCT orbit, these non-circular orbits exhibit significantly reduced metal artifacts. These results suggest a high potential for image quality improvements for intraoperative CBCT imaging when metal tools or implants are present in the field-of-view.

Technical assessment of 2D and 3D imaging performance of an IGZO-based flat-panel X-ray detector.

Indirect detection flat-panel detectors (FPDs) consisting of hydrogenated amorphous silicon (a-Si:H) thin-film transistors (TFTs) are a prevalent technology for digital x-ray imaging. However, their performance is challenged in applications requiring low exposure levels, high spatial resolution, and high frame rate. Emerging FPD designs using metal oxide TFTs may offer potential performance improvements compared to FPDs based on a-Si:H TFTs. This work investigates the imaging performance of a new indium gallium zinc oxide (IGZO) TFT-based detector in 2D fluoroscopy and 3D cone-beam CT (CBCT). The new FPD consists of a sensor array combining IGZO TFTs with a-Si:H photodiodes and a 0.7-mm thick CsI:Tl scintillator. The FPD was implemented on an x-ray imaging bench with system geometry emulating intraoperative CBCT. A conventional FPD with a-Si:H TFTs and a 0.6-mm thick CsI:Tl scintillator was similarly implemented as a basis of comparison. 2D imaging performance was characterized in terms of electronic noise, sensitivity, linearity, lag, spatial resolution (modulation transfer function, MTF), image noise (noise-power spectrum, NPS), and detective quantum efficiency (DQE) with entrance air kerma (EAK) ranging from 0.3 to 1.2 μGy. 3D imaging performance was evaluated in terms of the 3D MTF and noise-equivalent quanta (NEQ), soft-tissue contrast-to-noise ratio (CNR), and image quality evident in anthropomorphic phantoms for a range of anatomical sites and dose, with weighted air kerma, , ranging from 0.8 to 4.9 mGy. The 2D imaging performance of the IGZO-based FPD exhibited up to ∼1.7× lower electronic noise than the a-Si:H FPD at matched pixel pitch. Furthermore, the IGZO FPD exhibited ∼27% increase in mid-frequency DQE (1mm-1 ) at matched pixel size and dose (EAK ≈ 1.0 μGy) and ∼11% increase after adjusting for differences in scintillator thickness. 2D spatial resolution was limited by the scintillator for each FPD. The IGZO-based FPD demonstrated improved 3D NEQ at all spatial frequencies in both head (≥25% increase for all dose levels) and body (≥10% increase for ≤2 mGy) imaging scenarios. These characteristics translated to improved low-contrast visualization in anthropomorphic phantoms, demonstrating ≥10% improvement in CNR and extension of the low-dose range for which the detector is input-quantum limited. The IGZO-based FPD demonstrated improvements in electronic noise, image lag, and NEQ that translated to measurable improvements in 2D and 3D imaging performance compared to a conventional FPD based on a-Si:H TFTs. The improvements are most beneficial for 2D or 3D imaging scenarios involving low-dose and/or high-frame rate.

First Study in Men Evaluating a Surgical Robotic Tool Providing Autonomous Inner Ear Access for Cochlear Implantation

Image-guided and robot-assisted surgeries have found their applications in skullbase surgery. Technological improvements in terms of accuracy also opened new opportunities for robotically-assisted cochlear implantation surgery (RACIS). The HEARO® robotic system is an otological next-generation surgical robot to assist the surgeon. It first provides software-defined spatial boundaries for orientation and reference information to anatomical structures during otological and neurosurgical procedures. Second, it executes a preplanned drill trajectory through the temporal bone. Here, we report how safe the HEARO procedure can provide an autonomous minimally invasive inner ear access and the efficiency of this access to subsequently insert the electrode array during cochlear implantation. In 22 out of 25 included patients, the surgeon was able to complete the HEARO® procedure. The dedicated planning software (OTOPLAN®) allowed the surgeon to reconstruct a three-dimensional representation of all the relevant anatomical structures, designate the target on the cochlea, i.e., the round window, and plan the safest trajectory to reach it. This trajectory accommodated the safety distance to the critical structures while minimizing the insertion angles. A minimal distance of 0.4 and 0.3 mm was planned to facial nerve and chorda tympani, respectively. Intraoperative cone-beam CT supported safe passage for the 22 HEARO® procedures. The intraoperative accuracy analysis reported the following mean errors: 0.182 mm to target, 0.117 mm to facial nerve, and 0.107 mm to chorda tympani. This study demonstrates that microsurgical robotic technology can be used in different anatomical variations, even including a case of inner ear anomalies, with the geometrically correct keyhole to access to the inner ear. Future perspectives in RACIS may focus on improving intraoperative imaging, automated segmentation and trajectory, robotic insertion with controlled speed, and haptic feedback. This study [Experimental Antwerp robotic research otological surgery (EAR2OS) and Antwerp Robotic cochlear implantation (25 refers to 25 cases) (ARCI25)] was registered at clinicalTrials.gov under identifier NCT03746613 and NCT04102215.Clinical Trial Registrationhttps://www.clinicaltrials.gov, Identifier: NCT04102215.

Intraoperative cone beam assessment after reduction of zygomatic fractures helps in taking a decision on associated orbital floor fractures

IntroductionOrbital floor fracture (OFF) are frequently associated with zygomatic fractures (ZF). The reduction of the ZF may modify the features of the associated OFF. Intraoperative cone beam CT (CBCT) has shown diagnostic performance of OFF. The aim of our study was to evaluate how intraoperative CBCT control made after the reduction of ZF may help to take a decision on the associated OFF. Material and methodPatients with a unilateral displaced ZF associated with an OFF were consecutively included during a 3-year period. Intraoperative CBCT, systematically performed after reduction of the ZF, allowed to decide if the OFF needed reconstruction. The preoperative estimation made on MDCT and the intraoperative decision regarding the OFF were compared. ResultsFifty-nine consecutive patients could be included in the study. Nineteen OFF were presumed to be surgical indications on the preoperative MDCT but only 16 indications were confirmed on the intraoperative CBCT, meaning that 3 OFF behaved favorably during the ZF reduction. Forty orbital floor fractures were presumed to be non-surgical on the preoperative MDCT but 6 of them worsened during ZF reduction and became surgical indications. Overall, the intraoperative CBCT control had an impact on 9 (15.3%) of the OFF. ConclusionOur study showed that OFF after ZF reduction may evolve favorably or, on the contrary, get worse in 15% of the cases. Surgical indication on an OFF can therefore be confirmed intraoperatively. This allows to avoid under-treatment in the patients where the OFF worsens after ZF reduction and over-treatment in the patient where the OFF reduces after ZF.

Intraoperative cone-beam computed tomography to secure the surgical margin in pulmonary wedge resection for indistinct intrapulmonary lesions

ObjectiveThe objective of this study was to use cone-beam computed tomography (CBCT) for intraoperative imaging of a pulmonary wedge resection line that contributes to securing the required surgical margin in patients undergoing thoracoscopic surgery for indistinct intrapulmonary lesions.MethodsData of 16 consecutive patients with potentially impalpable intrapulmonary lesions were retrospectively reviewed. Preoperatively, we simulated a rhomboidal cut line on the surface of a 3-dimensional lung model with reference to multiplanar reconstruction computed tomography images. Intraoperatively, we imaged the rhomboid on the real lung surface using trial and error adjustment with CBCT. Wedge resection was performed thoracoscopically by stapling along the outline of the rhomboid.ResultsThe mean consolidation diameter and mean distance between the tumor and the visceral pleura were 2 mm and 11 mm, respectively. In all cases, we only performed single CBCT scanning to localize the rhomboid on the real lung surface. The mean radiological distance between the approximate location and the correct location was 8 mm (range, 0-34 mm). Wedge resection was successful with a mean surgical margin of 11 mm (range, 7-16 mm), without conversion to anatomical resection or open conversion. This simulation was also helpful for planning port placement for the use of an autostapler.ConclusionsWe established a novel procedure for imaging the cut line on the lung surface with intraoperative CBCT, which facilitated the performance of wedge resection with the required surgical margin in patients with potentially impalpable intrapulmonary small lesions. Our method might be beneficial for patients and surgeons because it can be applied without preoperative intervention.

Intraoperative Cone Beam CT in Hybrid Operating Room Set-Up as an Alternative to Postoperative CT for Pedicle Screw Breach Detection

Intraoperative Cone Beam CT in Hybrid Operating Room Set-Up as an Alternative to Postoperative CT for Pedicle Screw Breach Detection

Root Canal Treatment of Severely Calcified Teeth with Use of Cone-Beam Computed Tomography as an Intraoperative Resource.

The aim of this study was to describe a new strategy, consisting of the use of cone-beam computed tomography (CBCT) in the planning and intraoperative stages of root canal treatment (RCT), associated with the use of radiopaque gutta-percha markers, as an auxiliary tool in the location of severely calcified root canals. Three cases involving anterior and posterior teeth with severe calcification of the root canal were submitted to initial periapical radiographic and CBCT evaluations for diagnosis and planning of the operative steps. In a first intervention, when the location of the canal orifice was not successful, radiopaque markers were inserted in the suggested position of canal orifice with the aid of magnification and the use of ultrasonic devices, in order to perform an intraoperative CBCT analysis that allowed dynamic navigation through the static position of markers. The association of intraoperative CBCT with radiopaque markers allowed the location of the canal orifice and the following RCT execution. The use of CBCT in two different moments of RCT allowed the diagnosis of three-dimensional anatomical variations of root canal. Add, when associated with the use of radiopaque gutta-percha markers, acted as an auxiliary tool in the location of the canal orifice of calcified canals. Therefore, the presented strategy provides the clinician the precision that cases with calcification require and give an important contribution to treatment predictability.

The Charisma of 3D Imaging in Managing Endodontic Mishaps in Calcified Canal: A Case Report

Management of calcified canals is always challenging and is much more prone to mishaps such as perforations and ledge formations. The Two-dimensional (2D) imaging has a limitation, the 2D image of a Three-dimensional (3D) structure overlaps adjacent structures even over the root canals. This can create large confusion during treatment. Here, we are reporting a case where 2D imaging misled the treatment and 3D imaging evolved as a magical tool. A 32-year-old female, presented with complaints of pain, blackish discolouration and repeated sinus tract formation after her initial sitting of previous root canal treatment with upper right front tooth #11. On the radiograph, improper obturation and periapical radiolucency were evident. Hence, re-root canal treatment was advised and initiated. Gutta-percha was removed and radiographs were taken to ensure the removal of gutta-percha followed by working length estimation, which was satisfactory. After following all irrigation protocols, calcium hydroxide was placed as intracanal medicament but the patient came after 2 days with a draining pus sinus. The same happened with double antibiotic paste. Hence, Cone-beam Computed Tomography (CBCT) was advised. A buccal perforation and calcified unnegotiated canal were evident in all sections of CBCT. With the consent of the patient, the canal was again negotiated and guided with multiple angled radiographs. Intraoperative CBCT was advised with a master gutta-percha cone to verify the correct position of the canal. After verification, perforation was sealed with biodentine followed by obturation with crown placement in subsequent visits. Thus, 2D imaging can be misleading and 3D imaging is a guiding tool.

Automatic Registration and Error Color Maps to Improve Accuracy for Navigated Bone Tumor Surgery Using Intraoperative Cone-Beam CT.

Background:Computer-assisted surgery (CAS) can improve surgical precision in orthopaedic oncology. Accurate alignment of the patient’s imaging coordinates with the anatomy, known as registration, is one of the most challenging aspects of CAS and can be associated with substantial error. Using intraoperative, on-the-table, cone-beam computed tomography (CBCT), we performed a pilot clinical study to validate a method for automatic intraoperative registration.Methods:Patients who were ≥18 years of age, had benign bone tumors, and underwent resection were prospectively enrolled. In addition to inserting a navigation tracking tool into the exposed bone adjacent to the surgical field, 2 custom plastic ULTEM tracking tools (UTTs) were attached to each patient’s skin adjacent to the tumor using an adhesive. These were automatically localized within the 3-dimensional CBCT volume to be used as image landmarks for registration, and the corresponding tracker landmarks were captured using an infrared camera. The main outcomes were the fiducial registration error (FRE) and the target registration error (TRE). The navigation time was recorded.Results:Thirteen patients with benign tumors in the femur (n = 10), tibia (n = 2), and humerus (n = 1) underwent navigation-assisted resections. The mean values were 0.67 ± 0.15 mm (range, 0.47 to 0.97 mm) for FRE and 0.83 ± 0.51 mm (range, 0.42 to 2.28 mm) for TRE. Registration was successful in all cases. The mean time for CBCT imaging and tracker registration was 7.5 minutes.Conclusions:We present a novel automatic registration method for CAS exploiting intraoperative CBCT capabilities, which provided improved accuracy and reduced operative times compared with more traditional methods.Clinical Relevance:This proof-of-principle study validated a novel process for automatic registration to improve the accuracy of resecting bone tumors using a surgical navigation system.

Cone beam computed tomography for detecting residual stones in percutaneous nephrolithotomy, a randomized controlled trial (CAPTURE) protocol

IntroductionPercutaneous nephrolithotomy (PCNL) is the standard surgical treatment method for large kidney stones. Its aim is to achieve a stone-free status, since any residual fragments (RFs) after PCNL are likely to cause additional morbidity or stone growth. Enhancing intraoperative detectability of RFs could lead to increased stone-free rates and decreased re-intervention rates. Cone beam computed tomography (CBCT) has recently been introduced in urology as a feasible method for intraoperatively imaging RFs. The aim of this trial is to determine the added value of CBCT in percutaneous nephrolithotomy, by measuring differences in stone-related morbidity for patients with procedures in which a CBCT is used versus patients with procedures without the use of CBCT.MethodsThe CAPTURE trial is an investigator-initiated single-center, randomized controlled trial (RCT) in adult patients who have an indication for percutaneous nephrolithotomy. A contemporary percutaneous nephrolithotomy is performed. Once the surgeon is convinced of a stone-free status by means of fluoroscopy and nephroscopy, randomization allocates patients to either the study group in whom an intraoperative CBCT scan is performed or to the control group in whom no intraoperative CBCT scan is performed. The main endpoint is the stone-free status as assessed four weeks postoperatively by low-dose non-contrast abdominal CT, as a standard follow-up procedure. Secondary endpoints include the number of PCNL procedures required and the number of stone-related events (SREs) registered. The total study population will consist of 320 patients that undergo PCNL and are eligible for randomization for an intraoperative CBCT scan.DiscussionWe deem a randomized controlled trial to be the most effective and reliable method to assess the efficacy of CBCT in PCNL. Though some bias may occur due to the impossibility of blinding the urologist at randomization, we estimate that the pragmatic nature of the study, standardized circumstances, and follow-up methods with pre-defined outcome measures will result in a high level of evidence.Trial registrationNetherlands Trial Register (NTR) NL8168, ABR NL70728.042.19. Registered on 15 October 2019. Prospectively registered.

Abstract 1122‐000216: Evacuation of Bilateral Intracerebral Hemorrhages Using a Novel Disposable Surgiscopic System: A Case Report

Introduction : Patients presenting with intracerebral hemorrhage (ICH) face higher rates of morbidity and mortality than other stroke patients. Currently, these patients are managed by surgical intervention and decompression or medical management, depending on categorization of the hemorrhage. Simultaneous, multifocal hemorrhages are a rare presentation of ICH that portend a worse prognosis. Here we report the treatment of bilateral simultaneous ICHs in a young patient with diagnostic cerebral angiography, biopsy, and bilateral minimally invasive surgiscopic ICH evacuation in a single procedure. Methods : The patient was a young female who presented to an outside hospital after two days of progressively worsening headaches and vomiting. Her medical history was significant for systemic lupus erythematosus (SLE), hypertension, chronic migraines, and opioid use disorder. In the emergency department, her mental status deteriorated, and she was intubated. Computed tomography (CT) scan was performed and showed a right parietal 43.3 cc ICH and a left parietal 38.7 cc ICH. MR angiogram and venogram showed no evidence of vascular malformations but were suggestive of potential cerebral venous sinus thrombosis. Upon arrival, the patient remained intubated but was able to open her eyes, follow commands, and respond to stimulation. The patient was brought to the angiosuite for diagnostic cerebral angiography which revealed diffuse intermittent arterial narrowing suggestive of vasculitis and patent venous sinuses. The patient was then positioned in the prone position and bilateral parietal 1.5 cm craniectomies were performed. Surgiscopic evacuation was performed sequentially using stereotactic navigation to access and evacuate each clot. A right parietal brain biopsy was performed at the minimally invasive cortical access point. Results : Active bleeding was encountered in both hematoma sites and was treated with a combination of irrigation and monopolar cautery transmitted through the Aurora Evacuator. After complete evacuation of the hematomas on both sides, an intraoperative conebeam CT was performed, demonstrating good right‐sided evacuation and resident left‐sided hematoma. Additional evacuation was performed on the left side and repeat conebeam CT demonstrated good bilateral evacuation. CT head on post operative day 1 showed 97.7% right‐sided evacuation and 81.5% left‐sided evacuation. The patient was treated with steroids for presumed vasculitis given the angiographic findings, which was later supported by the results of the brain biopsy. The patient made a good recovery and was discharged from the hospital alert and oriented, with CN II‐XII grossly intact, no focal deficits, and 5/5 strength in all extremities. Conclusions : Minimally invasive ICH evacuation can be performed in the angiosuite for ICH‐associated with vasculitis and even multifocal ICH when appropriate. Performing the procedure in the angiosuite permits completion of the diagnostic cerebral angiogram, brain biopsy, and hematoma evacuation at the same time, accelerating time to treatment for a patient with severe, symptomatic vasculitis.

Zygomaticomaxillary complex fracture repair with intraoperative CBCT imaging. A prospective cohort study

The aim of this study was to evaluate the value of intraoperative conebeam computed tomography (CBCT) imaging in the treatment of zygomaticomaxillary complex (ZMC) fractures.A prospective single center cohort study was performed. Included were consecutive patients who underwent surgery for a unilateral ZMC fracture. An intraoperative CBCT scan was performed after reduction of the ZMC fracture. Revision reduction was performed of the ZMC and/or orbital floor (OF) on indication. The preoperative and postoperative asymmetry of the outer surface of the ZMC was measured on digital 3D-models of CBCT scans, using a mirroring and surface-based matching technique. The postoperative asymmetry of the ZMC in the study group was compared to the asymmetry of the ZMC in the control group with healthy individuals.A total of 38 patients with a unilateral ZMC fracture were included. The mean postoperative asymmetry in the study group (1.67 mm, SD 0.89) was less than the mean preoperative asymmetry (2.69 mm, SD 0.95) (paired samples T-test p < 0.01) but showed no statistically significant difference with the mean asymmetry in the healthy control group (1.40 mm, SD 0.54) (independent samples T-test p = 0.31). Revision reduction of the ZMC and/or OF fracture had been performed in 11 cases after malalignment was noted on the intraoperative CBCT. The indication for intraoperative revision reduction was associated with comminuted ZMC fractures and/or fractures with indication for OF reduction (Pearson Chi Square p < 0.01).Within the limitations of the study, intraoperative CBCT imaging seemed to have a positive influence on ZMC fracture treatment, especially in the case of comminuted ZMC fractures and/or fractures with indication for OF treatment.

Intraoperative cone-beam and slot-beam CT: 3D image quality and dose with a slot collimator on the O-arm imaging system.

To characterize the 3D imaging performance and radiation dose for a prototype slot-beam configuration on an intraoperative O-arm™ Surgical Imaging System (Medtronic Inc., Littleton, MA) and identify potential improvements in soft-tissue image quality for surgical interventions. A slot collimator was integrated with the O-arm™ system for slot-beam axial CT. The collimator can be automatically actuated to provide 1.2° slot-beam longitudinal collimation. Cone-beam and slot-beam configurations were investigated with and without an antiscatter grid (12:1 grid ratio, 60 lines/cm). Dose, scatter, image noise, and soft-tissue contrast resolution were evaluated in quantitative phantoms for head and body configurations over a range of exposure levels (beam energy and mAs), with reconstruction performed via filtered-backprojection. Qualitative imaging performance across various anatomical sites and imaging tasks was assessed with anthropomorphic head, abdomen, and pelvis phantoms. The dose for a slot-beam scan varied from 0.02-0.06 mGy/mAs for head protocols to 0.01-0.03 mGy/mAs for body protocols, yielding dose reduction by ∼1/5 to 1/3 compared to cone-beam, owing to beam collimation and reduced x-ray scatter. The slot-beam provided an ∼6-7× reduction in scatter-to-primary ratio (SPR) compared to the cone-beam, yielding SPR ∼20-80% for head and body without the grid and ∼7-30% with the grid. Compared to cone-beam scans at equivalent dose, slot-beam images exhibited an ∼2.5× increase in soft-tissue contrast-to-noise ratio (CNR) for both grid and gridless configurations. For slot-beam scans, a further ∼10-30% improvement in CNR was achieved when the grid was removed. Slot-beam imaging could benefit certain interventional scenarios in which improved visualization of soft tissues is required within a fairly narrow longitudinal region of interest ( 7mm in )--for example, checking the completeness of tumor resection, preservation of adjacent anatomy, or detection of complications (e.g., hemorrhage). While preserving existing capabilities for fluoroscopy and cone-beam CT, slot-beam scanning could enhance the utility of intraoperative imaging and provide a useful mode for safety and validation checks in image-guided surgery. The 3D imaging performance and dose of a prototype slot-beam CT configuration on the O-arm™ system was investigated. Substantial improvements in soft-tissue image quality and reduction in radiation dose are evident with the slot-beam configuration due to reduced x-ray scatter.

Intraoperative Cone Beam CT in Hybrid Operation Room for Pediatric Scoliosis Patients: Comparison of Pedicle Screw Violation Rate at Normal and Low Radiation Doses.

Retrospective observational study. This study aimed to determine the effect of reducing the radiation dose of intraoperative cone beam computed tomography (CBCT) during posterior spinal fusion (PSF) for pediatric scoliosis on the rate of pedicle screw (PS) violation. Intraoperative CBCT for pediatric scoliosis improves the accuracy of PS insertion in PSF. However, few reports have addressed the PS perforation rate from reduced radiation doses in hybrid navigation. We evaluated 855 PSs inserted into 58 pediatric scoliosis patients (11 male and 47 female, mean age: 16.6 yr) who underwent PSF using CBCT. A radiation dose of 1/3 or 1/5 of the normal dose (ND) was defined as a low dose (LD). After PS insertion, intraoperative CBCT images were reviewed to assess the degree of PS perforation. G2-3 (i.e., perforations of 4 mm or more) was defined as a violation. The PS violation rate was compared between the groups, and factors associated with violations were examined. A total of 567 and 288 screws were inserted in the ND group and LD group, respectively. The PS violation rate was comparable at 1.8% in the ND group and 1.7% in the LD group. Multiple logistic regression analysis showed that distance from the upper instrumented vertebra (UIV) was an independently associated factor of PS violation (+1 vertebra, operation room 0.73, P = 0.038). In addition, the mean height of patients with PS violations (148.8 ± 3.6 cm) was significantly shorter than that of patients without violations (157.9 ± 1.2 cm) ( P = 0.034). There was no increase in PS violation rate with lower doses of radiation for intraoperative navigation CBCT. Extra care is warranted for vertebrae close to the UIV and patients of shorter stature.Level of Evidence: 3.

Augmented reality navigation for cranial biopsy and external ventricular drain insertion.

The aim of this study was to evaluate the accuracy (deviation from the target or intended path) and efficacy (insertion time) of an augmented reality surgical navigation (ARSN) system for insertion of biopsy needles and external ventricular drains (EVDs), two common neurosurgical procedures that require high precision. The hybrid operating room-based ARSN system, comprising a robotic C-arm with intraoperative cone-beam CT (CBCT) and integrated video tracking of the patient and instruments using nonobtrusive adhesive optical markers, was used. A 3D-printed skull phantom with a realistic gelatinous brain model containing air-filled ventricles and 2-mm spherical biopsy targets was obtained. After initial CBCT acquisition for target registration and planning, ARSN was used for 30 cranial biopsies and 10 EVD insertions. Needle positions were verified by CBCT. The mean accuracy of the biopsy needle insertions (n = 30) was 0.8 mm ± 0.43 mm. The median path length was 39 mm (range 16-104 mm) and did not correlate to accuracy (p = 0.15). The median device insertion time was 149 seconds (range 87-233 seconds). The mean accuracy for the EVD insertions (n = 10) was 2.9 mm ± 0.8 mm at the tip with a 0.7° ± 0.5° angular deviation compared with the planned path, and the median insertion time was 188 seconds (range 135-400 seconds). This study demonstrated that ARSN can be used for navigation of percutaneous cranial biopsies and EVDs with high accuracy and efficacy.