Intraoperative Scanning Research Articles

Use of intraoperative CT scanning for quality control assessment of cochlear implant electrode array placement*

Background: Imaging of cochlear implant (CI) electrode arrays (EAs) consists of intraoperative fluoroscopy to rule out tip fold-over and/or post-operative computerized tomography (CT) if concern exists regarding extrusion or misplacement of the EA. Intraoperative CT (iCT) can satisfy these current needs and enables specification of final intracochlear position.Aims/objectives: To describe iCT scanning of CI recipients at an academic medical center.Materials and methods: iCT was used to scan CI recipients within the operating room before recovering from general anesthesia.Results: In fiscal year 2019, 301 CI were placed (83 children, 218 adult). One hundred, seventy-five iCTs were performed (58% of total CIs) of which 52 were children (63% of pediatric CIs) and 123 were adult (57% of adult CIs). Of 7 CI surgeons, use of iCT ranged from 14% to 100% (mean 60%). Four tip fold-overs were identified and corrected intraoperatively. Surgeons reported using the images to improve technique (i.e. pulling back precurved EAs to improve perimodiolar positioning).Conclusion and significance: The current standard of care for CI is to insert EAs without feedback as to final location. iCT provides surgeons with rapid post-insertion feedback which allows detection and correction of suboptimally placed EAs as well as refinement of surgical technique.

A new application of ultrasound-magnetic resonance multimodal fusion virtual navigation in glioma surgery.

Long-term survival and high-quality life of patients with gliomas depends on the extent of resection (EOR) and the protection of functional white matter fibers. The navigation system provides precise positioning for surgery based on preoperative magnetic resonance imaging (MRI) but the precision decreases when intraoperative brain drift occurs. Ultrasound (US) can support real-time imaging and correct brain shift. The real-time US-MRI multimodal fusion virtual navigation system (UMNS) is a new technique for glioma surgery. In order to obtain a maximum EOR and functional protection, this study aimed to explore the feasibility, efficiency, and safety of real-time UMNS for glioma surgery, and to evaluate the benefit of the new application by UMNS presetting markers between the tumor and functional white matter fiber surgery. A retrospective analysis included 45 patients who underwent glioma surgery, 19 patients with only intraoperative US, and 26 patients with UMNS. A preoperative plan was made by 3D-slicer software based on preoperative MRI. This was combined with a reconstruction of diffusion tensor imaging (DTI) that designed the important locations as "warning points" between functional white matter fibers and tumor. Following patient registration, markers were injected into preset "warning points" under image-guided UMNS in order to give us a warning during surgery in case of postoperative function deficits. The operating time, volumetric assessment in glioma resection, and postoperative complications were evaluated and used to compared those surgeries using intraoperative US (iUS) with those surgeries using intraoperate MRI (iMRI) navigation. A total of 45 patients underwent glioma surgery. Gross total removal (GTR) of iUS alone was achieved in 6 of 19 cases, while this was achieved in 22 of 26 cases with UMNS alone, demonstrating an improvement in rate of GTR from 31.58% to 84.62%, respectively. This may be attributable to the superior US image quality provided by UMNS. In 13 of 26 cases, there was improved image quality (from poor/moderate to moderate/good) with the aid of UMNS. In addition, the consistency of EOR of postoperative MRI evaluated by UMNS (92.31%) was higher than when using iUS alone (42.11%). The whole process of intraoperative scanning time and marker injection did not lead to a significant delay of the operating time compared to using iUS alone, and has been reported to be shorter than with iMRI as well. Furthermore, the percentage of postoperative morbidity in the UMNS group was lower than that in the iUS group (motor deficit: 11.54% vs. 42.11%; aphasia: P =3.85% vs. 31.58%, respectively). Real-time UMNS is an effective, timesaving technology that offers high quality intraoperative imaging. Injection markers between functional white matter fibers and tumor by UMNS can help to obtain a maximum EOR of glioma and functional protection postoperatively. The integration of iUS into the neuronavigation system offered quick and helpful intra-operative images.

Impact of Multi-modality Monitoring Using Direct Electrical Stimulation to Determine Corticospinal Tract Shift and Integrity in Tumors using the Intraoperative MRI.

Preserving the integrity of the corticospinal tract (CST) while maximizing the extent of tumor resection is one of the key principles of brain tumor surgery to prevent new neurologic deficits. Our goal was to determine the impact of the use of perioperative diffusion tensor imaging (DTI) fiber-tracking protocols for location of the CSTs, in conjunction with intraoperative direct electrical stimulation (DES) on patient neurologic outcomes. The role of combining DES and CST shift in intraoperative magnetic resonance imaging (iMRI) to enhance extent of resection (EOR) has not been studied previously. A total of 53 patients underwent resection of tumors adjacent to the motor gyrus and the underlying CST between June 5, 2009, and April 16, 2013. All cases were performed in the iMRI (BrainSuite 1.5 T). Preoperative DTI mapping and intraoperative cortical and subcortical DES including postoperative DTI mapping were performed in all patients. There were 32 men and 21 women with 40 high-grade gliomas (76%), 4 low-grade gliomas (8%), and 9 (17%) metastases. Thirty-four patients (64%) were newly diagnosed, and 19 (36%) had a previous resection. There were 31 (59%) right-sided and 22 (42%) left-sided tumors. Eighteen patients (34%) had a re-resection after the first intraoperative scan. Most patients had motor-only mapping, and one patient had both speech and motor mapping. Relative to the resection margin, the CST after the first iMRI was designated as having an outward shift (OS), inward shift (IS), or no shift (NS). A gross total resection (GTR) was achieved in 41 patients (77%), subtotal resection in 4 (7.5%), and a partial resection in 8 (15%). Eighteen patients had a re-resection, and the mean EOR increased from 84% to 95% (p = 0.002). Of the 18 patients, 7 had an IS, 8 an OS, and in 3 NS was noted. More patients in the OS group had a GTR compared with the IS or NS groups (p = 0.004). Patients were divided into four groups based on the proximity of the tumor to the CST as measured from the preoperative scan. Group 1 (32%) included patients whose tumors were 0 to 5 mm from the CST based on preoperative scans; group 2 (28%), 6 to 10 mm; group 3 (13%), 11 to 15 mm; and group 4 (26%), 16 to 20 mm, respectively. Patients in group 4 had fewer neurologic complications compared with other groups at 1 and 3 months postoperatively (p = 0.001 and p = 0.007, respectively) despite achieving a similar degree of resection (p = 0.61). Furthermore, the current of intraoperative DES was correlated to the distance of the tumor to the CST, and the regression equation showed a close linear relationship between the two parameters. Combining information about intraoperative CST and DES in the iMRI can enhance resection in brain tumors (77% had a GTR). The relative relationship between the positions of the CST to the resection cavity can be a dynamic process that could further influence the surgeon's decision about the stimulation parameters and EOR. Also, the patients with an OS of the CST relative to the resection cavity had a GTR comparable with the other groups.

Evaluation of the Contribution of Intraoperative Scans Coupled With the Navigation for the Precision of the Positioning of the Pedicle Screws During a Lumbar Spine Surgery: a Prospective Randomised Study

Evaluation of the Contribution of Intraoperative Scans Coupled With the Navigation for the Precision of the Positioning of the Pedicle Screws During a Lumbar Spine Surgery: a Prospective Randomised Study

Intra-Operative 3-Dimensional Imaging (O-arm) in Foot and Ankle Trauma Surgery: Report of 2 Cases and Review of the Literature

Background: Intraoperative two-dimensional (2D) fluoroscopy is the standard imaging modality available to orthopaedic surgeons worldwide. It is well-accepted, however, multiplanar 3 dimensional (3D) CT scanning is superior to 2D imaging for visualising joint surfaces and is now a fundamental feature of the pre-operative planning of intra-articular fractures. Objective: We present two cases in which the use of 3D intraoperative imaging and the O-arm® (Medtronic, Minneapolis, USA) led to immediate intraoperative revision to optimise fixation and articular congruity. A review of the current literature is also provided. Methods: During the trial period of the O-arm at our major trauma centre, intra-operative imaging was used in the lower limb trauma setting. The O-arm was used intra-operatively in a comminuted pilon fracture and a displaced talus fracture. We recorded all the intra-operative events, including quality of reduction, implant positioning and operation time. Each patient was followed-up for 12 months post-operation and was finally assessed with x-rays and the AOFAS score. Results: In both the cases, either fracture reduction or the implant position/usage that was observed with 2D fluoroscopy was revised following a 3D intra-operative scan. No postoperative complications were noted and the healing process was uneventful. X-rays at the final follow-up were excellent and acceptable for the talus and pilon fracture, respectively, with corresponding clinical results and AOFAS score. Conclusion: Although frequently used in spinal surgery, to the best of our knowledge, the use of intra-operative 3D techniques in lower limb trauma is sparse and sporadically reported. We present our cases in which the most current innovative imaging techniques influenced intra-operative outcomes without compromising patient safety. We feel that this is a real example of how innovation can positively influence patient care.

The image-guided operating room-Utility and impact on surgeon's performance in the head and neck surgery.

The image-guided operating room (OR) is an emerging standard for dealing with complex cases in many surgical disciplines including neurosurgery, thoracic surgery, maxillofacial trauma, and orthopedic surgery. Its use in head and neck oncological surgery is not well established. The primary aim of this study was to assess the image quality of cone-beam CT (CBCT) under real clinical conditions. The secondary aim was to assess the effect on surgical performance and decision making. Intraoperative 3D imaging was performed using a CBCT capable C-Arm mounted on a multi-axis robot (Siemens Zeego) in the image-guided OR. All patients had immediate preoperative imaging taken with further intraoperative imaging performed as required. Ten initial patients, comprising 28 intraoperative scans, were used for questionnaire-based image reviews conducted with experienced head and neck clinicians. Scans were assessed for aspects of both image quality and clinical utility, on separate 5-point Likert scales (1-5). The median rating for bony detail was 4 out of 5. Vascular detail was increased (P < 10-8 ) from 1 to 3 with the use of IV contrast (region of interest CT# was 284 HU [SD, 47 HU]). Images were rated as 4 for freedom from artifact. Soft tissue definition was 2, with no significant improvement (P = .2) with the addition of IV iodinated contrast. Surgeons rated the greatest clinical utility (4) for the CBCT when assessing postreconstruction imaging of a complex case. The image quality of CBCT in the image-guided OR is good for bony detail and complex oncological reconstructions in the head and neck setting but probably has limited benefit for intraoperative soft tissue delineation. Future studies must also focus on clinical outcomes to help demonstrate the value of the image-guided OR.

P.120 Rapid intraoperative reconstruction of cranial implants for craniotomy procedures: a feasibility study

Background: The aim of this study was to investigate intraoperative methods to generate patient-specific PMMA bone implants during a craniotomy. The proposed methods combine a cost-efficient, and non-invasive structured light scanner (SLS) as an imaging modality and a prototype printer for rapid generation of implant molds. Methods: This simulation study was performed using retrospective data from three craniotomy patients. The extracted bone flap and the cranial defect were scanned using a SLS, which generates a 3D surface model of an object by projecting a series of light-patterns on it. Prototype printed implant models were generated using two different techniques. The molds were then used to shape PMMA bone implants. These implants were evaluated regarding their accuracy to reconstruct the natural skull anatomy and compared to freehand formed implants. Results: The patient-specific bone implants reconstructed the preoperative anatomy with an average RMS error of 1.37mm (StDev 0.27), compared to an error of 1.5mm (StDev 0.43) for the freehand shaped implants. On average the intraoperative scanning time was 4.7min. The average time to generate and print the implant molds was 204 min. Conclusions: Results of this study have shown great promise for the proposed method to be used for patient-specific bone flap reconstruction during craniotomies.

Image Guided Navigation Utilizing Intra-operative 3D Surface Scanning to Mitigate Morphological Deformation of Surface Anatomy

The purpose of this study is to navigate an in-house robot under uncertain intraoperative changes of the body surface which is not present in the pre-operative scan in hospital environments and lab environment. The proposed methodology involves the use of a 3D scanner to form a 3D model. The method used in this study is cost effective and takes less time (about 5–7 min). We focused more on the surface anatomical positions of a patient, which may change after a pre-operative scan. With respect to this, we introduced a method to include these deformed regions in navigation, which are not present in pre-operative scans. By creating an on-spot 3D surface model of the cadaver’s and phantom’s head, and after registration processes we completed the surgical navigation process with an error (root-mean-square error) of 0.568 mm and 0.791 mm for phantom and cadaver respectively. We showed the successful surgical navigation by using on-spot 3D surface modeling and including the deformity in our system. The accuracy of registration in lab condition and hospital condition was compared.

Application of intraoperative magnetic resonance imaging in endoscopic transsphenoidal surgery for recurrent pituitary adenomas

Objective To investigate the clinical value of intraoperative magnetic resonance imaging (iMRI) in endoscopic transsphenoidal surgery for recurrent pituitary adenomas. Methods A retrospective analysis was conducted on 29 cases of surgically treated patients with recurrent pituitary adenomas at Neurosurgery Department of the First Medical Center of Chinese PLA Greneral Hospital from February 2009 to February 2015. All patients underwent surgical resection of tumor with intraoperative magnetic resonance imaging. The parameters evaluated included the extent of tumor resection, scanning frequency and timing, relief of symptoms and signs, follow-up results and complications. Results Among 24 patients with possible totally resection according to the Knosp grading, 16 showed total tumor resection through the first intraoperative scanning and the second intraoperative scanning revealed another 4 cases achieving total resection after extended resection. After more than 3 times of extended resection, intraoperative scanning revealed 2 patients with total resection and the remaining 2 patients had residual tumor tissues. The number of intraoperative scanning was 1.6±0.8 times per case and the average scanning duration was 45.9±19.3 minutes. The total time for surgery was 157.2±55.6 minutes. The postoperative headache remission ratio was 11/13 and the visual dysfunction remission ratio was 12/15. Postoperative pituitary insufficiency occurred in 2 cases, olfactory disorder in 1 case, temporary diabetes insipidation in 7 cases and cerebrospinal fluid leakage in 2 cases. Twenty-nine patients were followed up for 3 to 67 months, with an average of 46.6±19.4 months. There were 2 patients with tumor recurrence among the 22 patients with total tumor resection. Conclusion For recurrent pituitary adenomas, iMRI-assisted endoscopic resection seems to be a safe and effective treatment which has high rate of total resection and less postoperative complications. Key words: Pituitary neoplasms; Neoplasm recurrence, local; Neurosurgical procedures; Intraoperative magnetic resonance imaging; Natural orifice endoscopic surgery

Review of first clinical experiences with a 1.5 Tesla ceiling-mounted moveable intraoperative MRI system in Europe.

High-field intraoperative MRI (iMRI) systems provide excellent imaging quality and are used for resection control and update of image guidance systems in a number of centers. A ceiling-mounted intraoperative MRI system has several advantages compared to a conventional iMRI system. In this article, we report on first clinical experience with using such a state-of-the-art, the 1.5T iMRI system, in Europe. A total of 50 consecutive patients with intracranial tumors and vascular lesions were operated in the iMRI unit. We analyzed the patients' data, surgery preparation times, intraoperative scans, surgical time, and radicality of tumor removal. Patients' mean age was 46 years (range 8 to 77 years) and the median surgical procedure time was 5 hours (range 1 to 11 hours). The lesions included 6 low-grade gliomas, 8 grade III astrocytomas, 10 glioblastomas, 7 metastases, 7 pituitary adenomas, 2 cavernomas, 2 lymphomas, 1 cortical dysplasia, 3 aneurysms, 1 arterio-venous malformation and 1 extracranial-intracranial bypass, 1 clival chordoma, and 1 Chiari malformation. In the surgical treatment of tumor lesions, intraoperative imaging depicted tumor remnant in 29.7% of the cases, which led to a change in the intraoperative strategy. The mobile 1.5T iMRI system proved to be safe and allowed an optimal workflow in the iMRI unit. Due to the fact that the MRI scanner is moved into the operating room only for imaging, the working environment is comparable to a regular operating room.

Is bony attachment necessary for dynamic reference frame in navigation-assisted minimally invasive lumbar spine fusion surgery?

This study aimed to compare the accuracy of navigation-assisted percutaneous pedicle screw insertions between traditional posterior superior iliac spine (PSIS) fixed and cutaneously fixed dynamic reference frame (DRF) in minimally invasive surgery of transforaminal lumbar interbody fusion (MIS TLIF). This is a prospective randomized clinical study. Between May 2016 and Nov 2017, 100 patients who underwent MIS TLIF were randomly divided into bone fixed group (with PSIS fixed DRF) and skin fixed group (with cutaneously fixed DRF). The pedicel screws were inserted under navigational guidance using computed tomography (CT) data acquired intraoperatively with a Ziehm 3-dimensional fluoroscopy-based navigation system. Screw positions were immediately checked by a final intraoperative scan. The accuracy of screw placement was evaluated by a sophisticated computed tomography protocol. Both groups had similar patient demographics. Totally Five-hundred Twelve pedicle screws were placed in the lumbar spine. There were 2 moderate (2–4 mm) pedicle perforations in each group. The accuracy showed no significant difference between bone fixed and skin fixed DRF. There were no significant procedure-related complications. The skin fixed DRF provides similar accuracy in pedicle screw insertions with bone fixed DRF using intraoperative 3D image guided navigation in MIS TLIF. Skin fixed DRF not only serves as an alternative method but also saves a separate incision wound for bony attachment.

Implementation of Intraoperative Computed Tomography for Deep Brain Stimulation: Pitfalls and Optimization of Workflow, Accuracy, and Radiation Exposure

Deep brain stimulation (DBS) is an effective treatment for movement disorders. Stereotactic electrode placement can be guided by intraoperative imaging, which also allows for immediate intraoperative quality control. This article is about implementation and refining a workflow applying intraoperative computed tomography (iCT) for DBS. Eighteen patients underwent DBS with bilateral implantation of directional electrodes applying a 32-slice movable computed tomography scanner in combination with microelectrode recording. iCT led to a significant decrease in overall procedural time, despite performing multiple scans. In 3 of the initial 5 cases, iCT caused an adjustment of the final electrodes demonstrating the learning curve and the necessity to integrate road mapping for the exchange of microelectrode to final electrode. Implementation of low-dose computed tomography protocols added microelectrode iCT to the refined workflow, resulting in an intraoperative adjustment of a trajectory in 1 patient. Low-dose protocols lowered the total effective dose to 1.15 mSv, that is, a reduction by a factor of 3.5 compared to a standard non-iCT DBS procedure, despite repeated iCTs. Intraoperative lead detection based on final iCT revealed a radial error of 1.04 ± 0.58 mm and a vector error of 2.28 ± 0.97 mm compared to the preoperative planning, adjusted by the findings of microelectrode recording. iCT can be easily integrated into the surgical workflow resulting in an overall efficient time-saving procedure. Repeated intraoperative scanning ensures reliable electrode placement, although low-dose scanning protocols prevent extensive radiation exposure. iCT of microelectrodes is feasible and led to the adjustment of 1 electrode.

On-Demand Intraoperative 3-Dimensional Printing of Custom Cranioplastic Prostheses.

Currently, implantation of patient-specific cranial prostheses requires reoperation after a period for design and formulation by a third-party manufacturer. Recently, 3-dimensional (3D) printing via fused deposition modeling has demonstrated increased ease of use, rapid production time, and significantly reduced costs, enabling expanded potential for surgical application. Three-dimensional printing may allow neurosurgeons to remove bone, perform a rapid intraoperative scan of the opening, and 3D print custom cranioplastic prostheses during the remainder of the procedure. To evaluate the feasibility of using a commercially available 3D printer to develop and produce on-demand intraoperative patient-specific cranioplastic prostheses in real time and assess the associated costs, fabrication time, and technical difficulty. Five different craniectomies were each fashioned on 3 cadaveric specimens (6 sides) to sample regions with varying topography, size, thickness, curvature, and complexity. Computed tomography-based cranioplastic implants were designed, formulated, and implanted. Accuracy of development and fabrication, as well as implantation ability and fit, integration with exiting fixation devices, and incorporation of integrated seamless fixation plates were qualitatively evaluated. All cranioprostheses were successfully designed and printed. Average time for design, from importation of scan data to initiation of printing, was 14.6 min and average print time for all cranioprostheses was 108.6 min. On-demand 3D printing of cranial prostheses is a simple, feasible, inexpensive, and rapid solution that may help improve cosmetic outcomes; significantly reduce production time and cost-expanding availability; eliminate the need for reoperation in select cases, reducing morbidity; and has the potential to decrease perioperative complications including infection and resorption.

Setting Up Workflow of an Intraoperative MRI Unit: A Single-Centre Experience of First 53 Cases

Abstract Background Setting up of a new “nearby” operation room type intraoperative magnetic resonance imaging (iMRI) unit poses a unique set of challenges to the operating team. We describe here an account of our experiences and a step by step protocol designed by us and followed to troubleshoot the issues encountered. The primary objective of the study was to observe our learning curve in the process of setting up of a new iMRI unit. The secondary objectives were to look at the number of residues detected, quality of imaging, and complications during iMRI. Materials and Methods An observational study was conducted over a 3-month period involving cases requiring iMRI. Initially, a simulation was performed using healthy volunteers, which helped in developing a systematic protocol and drafting checklists to ensure a smooth workflow pattern. Data collection included details regarding hindrances encountered, how these were tackled, iMRI details (residual tumor, re-surgery), and complications, if any. Results A total of 53 cases underwent iMRI in the study period. Among these, 51 were tumor cases that revealed residue (detected in 28 [54.9%] cases), and re-surgery for further resection was performed in 21/28 (75%) cases. A very high level of surgeons’ satisfaction regarding image quality of intraoperative scan was recorded (45/53 [84%]). The number of personnel required for shifting and shifting times could be reduced with efficient utilization of the checklist. Conclusion A methodical approach to tackle impediments while setting up a new unit such as iMRI facilitates its smooth functioning and ensures minimal interruptions and evades undue complications.

Intraprocedural C-arm CT assisted trans-perforator embolization of deep arteriovenous malformations

Objective To explore the application of intraprocedural C-arm CT assisted trans-perforator embolization of deep arteriovenous malformations (AVM). Methods From July 2015 to June 2017 at Neurosurgery Department, Xuanwu Hospital Capital Medical University, a total of 21 cases of hemorrhagic deep AVM were retrospectively reviewed. There were 11 men and 10 women with the average age of 24.3 years old. Among them, 20 lesions were located at the basal ganglia and 1 lesion at the fourth ventricle. Three lesions were classified as Spetzler-Martin grade 4 and 18 lesions were grade 3. All patients were treated with transarterial embolization under general anesthesia. The tip of microcatheter was localized with intraoperative C-arm CT technique when trans-perforator embolization was intended. Results Among 21 patients, a total of 49 times of embolization were performed. Twenty-five times of intraoperative C-arm CT scans were used in 37 times of trans-perforator embolization. The tip of microcatheter was positioned 22 times at the safe region and 3 times at the dangerous area. The immediate post-operative angiography revealed complete occlusion or subtotal occlusion in 8 cases, obliteration of hemorrhage-related structures in 11 and partial embolization in 2. Intraoperative ventricular hemorrhage occurred in 2 cases and 1 of them presented with numbness of contralateral extremities post embolization. Twelve cases were followed up by DSA at 4-17 months post embolization. Five lesions which were obliterated completely or subtotally developed no further changes in follow-up angiogram when compared with immediate post-operative results. In 7 lesions which were treated with obliteration of hemorrhage-related structures, the nidus of 1 lesion disappeared completely and that in 6 other lesions had residues without hemorrhage-related structures. The remaining 9 cases were clinically followed up at 6 months post embolization. Recurrent hemorrhage and new-onset neurologic deficits were not found during follow-up period. Conclusion The tip of microcatheter could be localized with the assistance of intraoperative C-arm CT technique, which might facilitate more precise trans-perforator embolization for deep AVM. Key words: Intracranial arteriovenous malformations; Embolization, therapeutic; Tomography, X-ray computed; Perforator artery

A comparison of arterial spin labeling and dynamic susceptibility perfusion imaging for resection control in glioblastoma surgery.

Resection control using magnetic resonance imaging during neurosurgical interventions increases confidence regarding the extent of tumor removal already during the procedure. In addition to morphological imaging, functional information such as perfusion might become an important marker of the presence and extent of residual tumor mass. The aim of this study was to implement arterial spin labeling (ASL) perfusion imaging as a noninvasive alternative to dynamic susceptibility contrast (DSC) perfusion imaging in patients suffering from intra-axial tumors for resection control already during surgery. The study included 15 patients suffering from glioblastoma multiforme in whom perfusion imaging using DSC and ASL was performed before, during, and after surgery. The data obtained from intraoperative scanning were analyzed by two readers blinded to any clinical information, and the presence of residual tumor mass was evaluated using a ranking scale. Similarity of results was analyzed using the intraclass correlation coefficient and Pearson's correlation coefficient. The results show that intraoperative ASL is as reliable as DSC when performing intraoperative perfusion imaging. According to the results of this study, intraoperative imaging using ASL represents an attractive alternative to contrast agent-based perfusion imaging.

Motion preservation surgery: excision of juxta C5-C6 intervertebral disc osteoid osteoma using 3D C-arm based navigation: technical report.

Introduction: Precise targeted excision of the C5–C6 osteoid osteoma with placement of reference array on clavicle with minimal disturbance of anatomy and motion.Methods: A 20-year-old male presented with an osteoid osteoma in the superior end plate of the C6 vertebra abutting the spinal canal causing intractable pain. The authors curetted the nidus using a 3D C-arm-based intraoperative scan integrated with an optical navigation system through a minimal access anterior cervical exposure. The patient reference array was affixed to the left clavicle using a threaded pin.Results: The postoperative CT-scan revealed complete excision. Follow-up MRI and CT after 12 months revealed C5–C6 intervertebral disc to be intact without evidence of any tumor recurrence. VAS for neck pain improved from 8/10 to 2/10 immediately postoperatively and 0/10 at 1 year follow-up with no limitation of cervical movement. A motion segment was preserved with this technique.Conclusions: Navigation allowed safe curettage of the nidus with minimal disturbance to the anatomy and motion. The site of attachment of patient reference array on clavicle can be recommended as stable, meeting all the criteria for optimal accuracy and stability.

Use of Intraoperative Computed Tomography in Craniomaxillofacial Trauma Surgery

The use of technology to aid in assessment, planning, and management of complex craniomaxillofacial injuries is increasingly common. Preoperative computed tomography (CT) evaluation is considered the standard of care, and intraoperative imaging is becoming increasingly accessible. Limited data exist regarding the implication of intraoperative CT on decision making in the management of all sites of facial fractures. The purposes of this study were to characterize the use of an intraoperative CT scanner for craniomaxillofacial surgery within our institution, to quantify the effect of intraoperative CT on surgical decision making, and to attempt to provide guidance on when to use this technology. This retrospective case series characterizes the use of an intraoperative CT scanner for craniomaxillofacial trauma surgery at a level 1 trauma center in Portland, Oregon, from February 2011 to September 2016. We evaluated the following variables: the number of intraoperative CT scans performed for craniomaxillofacial surgery including the number of scans for each patient, the number of scans for each operative visit, the CT-directed revision rate (overall and for specific preoperative diagnoses), and the indication for imaging. This information was evaluated to provide guidance on appropriate use of an intraoperative scanner. A total of 161 patients were identified to have intraoperative facial CT scans from February 2011 to September 20, 2016, at Legacy Emanuel Medical Center. A total of 212 intraoperative facial CT scans were performed across 168 separate operations. The overall CT-directed revision rate was 28%. CT-directed revision rates for fracture subsites are as follows: orbital, 31%; zygomaticomaxillary complex, 24%; Le Fort I, 8%; Le Fort II and III, 23%; naso-orbital-ethmoidal, 23%; mandible, 13%; and frontal sinus, 0%. No CT-directed revisions were performed during removal of hardware, during placement of craniofacial implants, or in temporomandibular joint replacement surgery. If available, intraoperative CT should be routinely considered in the operative management of orbital fractures and pan-facial fractures, as well as complex zygomaticomaxillary complex, LeFort II and III, and naso-orbital-ethmoidal fractures.Consideration also should be given to the use of intraoperative CT in cases of complex mandible fractures involving severe comminution or the condylar region. Intraoperative CT should not be routinely used for the management of Le Fort I fractures or frontal sinus fractures.

Mobile C-arm CT scan in surgery for thoracolumbar burst fractures of type A3

Objective To discuss the application of mobile C-arm CT scan in the operations for thora-columbar burst fractures of type A3. Methods From January 2012 to December 2014, 21 patients with sin-gle-segment thoracolumbar burst fracture (AO type A3) were treated. They were 15 males and 6 females, aged from 17 to 68 years (average, 43.6 years). By the American Spinal Injury Association (ASIA) grading, one was grade A, 2 were grade B, 12 grade C, 4 grade D and 2 grade E. Preoperative CT examination was conducted. Mobile C-arm CT scan was performed to evaluate reduction of the fragments after the fracture was reset by posterior pedicle screwing. Laminotomy for canal decompression or reduction of the fragments would be performed if it was indicated by the results of mobile C-arm CT scan. CT examination was conducted postoperatively to assess the fracture re-duction and recovery of the canal calibre. Results All the patients were followed up for an average of 15.5 months (from 10 to 18 months). Their cobb angle, vertebral anterior margin compression rate, spinal occupancy rate, vertebral translocation rate and visual analogue score at postoperation and final follow-up were significantly improved compared with their preoperative values (P 0.05). Postoperative ASIA grading showed that the spinal function was improved from grade B to grade C in one, from grade C to grade D in 4 cases, from grade C to grade E in 5 cases, and from grade D to grade E in 3 cases. Conclusion Since intraoperative C-arm CT scan can help decide whether laminectomy for canal decompression is conducted or not in the surgery of thoracolumbar burst fractures, it enhances the surgical safety and reliability. Key words: Thoracic vertebrae; Lumbar vertebrae; Fractures,bone; Fracture fixation,internal; C-arm CT

Detection of articular perforations of the proximal humerus fracture using a mobile 3D image intensifier \u2013 a cadaver study

BackgroundThe purpose of this study was to investigate the accuracy of perforation detection with multiplanar reconstructions using a mobile 3D image intensifier.MethodsIn 12 paired human humeri, K-wires perforating the subchondral bone and placed just below the cartilage level were directed toward five specific regions in the humeral head. Image acquisition was initiated by a fluoroscopy scan. Within a range of 90°, 45° external rotation (ER) and 45° internal rotation (IR). The number and percentage of detected perforating screws were grouped and analyzed. Furthermore, the fluoroscopic images were converted into multiplanar CT-like reconstructions. Each K-wire perforation was characterized as “detected” or “not detected”.ResultsIn the series of fluoroscopy images in the standard neutral position at 30° internal rotation, and 30° external rotation, the perforations of all K-wires (n = 56) were detected. Twenty-nine (51.8%) of them were detected in one AP view, 22 (39.3%) in two AP views, and five (8.9%) in three AP views. All K-wire perforations (100%, n = 56) were detected in multiplanar reconstructions.ConclusionIn order to reveal all of the intraoperative and postoperative screw perforations in a “five screw configuration”, conventional AP images should be established in both the neutral positions (0°), at 30° internal rotation and 30° external rotation. Alternatively, the intraoperative 3D scan with multiplanar reconstructions enables a 100% rate of detection of the screw perforations.