Intraoperative Three-dimensional Imaging Research Articles

Surgical treatment of nasal fractures may benefit from intraoperative 3D imaging

This retrospective study aimed to assess the effects of the use of intraoperative three-dimensional (3D) imaging on outcomes in surgical treatment of nasal fractures. Furthermore, we investigated whether the use of intraoperative imaging improves outcomes and decreases the frequency of corrective surgeries compared to published literature. This retrospective descriptive study included patients who underwent operative treatment for nasal fractures with the use of intraoperative 3D imaging between January 2015 and January 2020at a University Hospital. The primary outcome measure was patient satisfaction, which was assessed through patient charts about subjective esthetic problems and nasal obstruction. The secondary outcome measures were the number of intraoperative images and necessity of intra- and postoperative revisions. All the outcomes were evaluated using regression analysis. Of the 172 patients, secondary rhinoplasty and intraoperative revision were performed in 10 (6 %) and 93 (54 %) patients, respectively. Postoperatively, 19 (11 %) and 12 (7 %) patients complained of subjective esthetic problems and nasal obstruction, respectively. The intraoperative revision rate in patients undergoing surgical treatment of nasal fractures with intraoperative 3D imaging was >50 %. However, the incidence of postoperative secondary revision, nasal obstruction, and subjective esthetic problems was lower than that reported in the literature not having an intraoperative imaging. Our findings suggest that prompt quality control of the operative result enables immediate correction and prevents postoperative revision.

Erector Spinae Plane Block Placement Utilizing Fluoroscopic Guidance Improves Efficiency in Lumbar Surgery

The erector spinae plane block (ESPB) is a novel regional analgesic technique which improves postoperative outcomes in lumbar surgery patients including length of hospitalization, days to ambulation, and postoperative opioid use. Traditionally, the block is administered by anesthesiologists trained in the ultrasound guidance technique. The use of fluoroscopic guidance may improve the efficiency and accessibility of the ESPB for spine surgeons. We aim to measure the time to administer an ESPB using fluoroscopic guidance and localize the anesthetic using intraoperative three-dimensional (3D) imaging. Two neurosurgeons administered an ESPB to patients undergoing lumbar surgery. Time from insertion of the spinal needle to localize the erector spinae plane using C-arm guidance to time of complete injection and removal of the needle from the skin was recorded. One patient underwent O-arm imaging following injection of an Isovue-Exparel solution at the L3 level to visualize spread of the anesthetic. A total of 21 patients were enrolled in this study. The average duration to perform an ESPB under fluoroscopic guidance was 1.2minutes. The Isovue-Exparel solution was injected at the L3 level and was well distributed along the ESP on intraoperative O-arm imaging. The anesthetic dissected the erector spinae muscle from the transverse process at L2, L3, and L4. Fluoroscopic guidance allows efficient and appropriate delivery of the anesthetic to the erector spinae plane. Performing an ESPB with fluoroscopic guidance improves efficiency and accessibility of the analgesic technique for spine surgeons, reducing dependence on anesthesiology personnel trained in administering the block.

Assessing intraoperative pedicle screw placement accuracy using biplanar radiographs compared to three-dimensional imaging.

To date, biplanar imaging (2D) has been the method of choice for pedicle screw (PS) positioning and verified for the anteroposterior view and (spinal midline) M-line method. In recent years, the use of intraoperative three-dimensional (3D) imaging has become available with the Gertzbein-Robbins system (GRS) to assess PS breach and positioning confirmation. The aim is to determine if 2D imaging is sufficient to assess PS position in comparison to advanced 3D imaging.Retrospective review of prospectively collected data from 204 consecutive adult patients who underwent posterior thoracic and lumbar instrumented fusion for degenerative spinal surgery by a single surgeon (2019-2022).Of the 204 patients, 187 (91.6%) had intraoperative images available for analysis. A total of 1044 PS implants were used; 922 (88.3%) were robotically placed. Postoperative CT scans were verified with M-line/GRS findings. Among 103 patients (50.5%) with a total of 362 screws, (34.7%) had postoperative CT, intraoperative 3D scan, and intraoperative 2D scan for analysis. Postoperative CT findings were consistent with all GRS findings, validating that 3D imaging was accurate. Screws (1%) were falsely verified by the M-line as 3D imaging confirmed false negative or positive findings.In our series, intraoperative 3D scan was as accurate as postoperative CT scan in assessing PS breach. A significant number of PS may be falsely read as accurate on 2D imaging, that is in fact inaccurate when assessed on 3D imaging. An intraoperative post-instrumentation 3D scan may be preferable to prevent postoperative recognition of a falsely verified screw on biplanar imaging.

Evaluating a cutting-edge augmented reality-supported navigation system for spinal instrumentation

ObjectiveDorsal instrumentation using pedicle screws is a standard treatment for multiple spinal pathologies, such as trauma, infection, or degenerative indications. Intraoperative three-dimensional (3D) imaging and navigated pedicle screw placement are used at multiple centers. For the present study, we evaluated a new navigation system enabling augmented reality (AR)-supported pedicle screw placement while integrating navigation cameras into the reference array and drill guide. The present study aimed to evaluate its clinical application regarding safety, efficacy, and accuracy.MethodsA total of 20 patients were operated on between 06/2021 and 01/2022 using the new technique for intraoperative navigation. Intraoperative data with a focus on accuracy and patient safety, including patient outcome, were analyzed. The accuracy of pedicle screw placement was evaluated by intraoperative CT imaging.ResultsA median of 8 (4–18) pedicle screws were placed in each case. Percutaneous instrumentation was performed in 14 patients (70%). The duration of pedicle screw placement (duration scan–scan) was 56 ± 26 (30–107) min. Intraoperative screw revision was necessary for 3 of 180 pedicle screws (1.7%). Intraoperatively, no major complications occurred—one case of delay due to software issues and one case of difficult screw placement were reported.ConclusionThe current study's results could confirm the use of the present AR-supported system for navigated pedicle screw placement for dorsal instrumentation in clinical routine. It provides a reliable and safe tool for 3D imaging-based pedicle screw placement, only requires a minimal intraoperative setup, and provides new opportunities by integrating AR.

PE057 - Robotic partial nephroureterectomy for T1b renal cell carcinoma with complete situs inversus totalis with pre- and intraoperative three-dimensional virtual imaging

PE057 - Robotic partial nephroureterectomy for T1b renal cell carcinoma with complete situs inversus totalis with pre- and intraoperative three-dimensional virtual imaging

On the use of intraoperative 3D-RX C-arm imaging in orthognathic surgery: a prospective non-consecutive case series study.

Segment and osteosynthesis malposition resulting in patients' complaints (mainly about asymmetries) are encountered in orthofacial/orthognathic surgery. We planned to investigate the usefulness of intraoperative three-dimensional (3D) imaging concerning positioning and fixation of bone segments and osteosynthesis in orthognathic/orthofacial surgery. We performed a prospective study of non-consecutive cases. All patients receiving a bimaxillary osteotomy, genioplasty, and their combinations were included in the study from May 2016 to May 2020. Unilateral and bilateral sagittal split osteotomies were excluded. There were no gender and age limitations. All were intraoperatively examined using the BV Pulsera 3D-RX System (Philips Medical, Eindhoven, The Netherlands). The outcome variables were the percentage of revisions of segment positioning and osteosynthesis. Predictor variables were age, gender, type of surgery, timing (pre- and post-imaging), and surgeon experience (senior vs assistant). Forty female and twenty-two male patients were included (mean age 25.25years ± 7.52 and 29.1years ± 12.6 respectively). We evaluated 27 genioplasties and 34 Le Fort "type-I" osteotomies. Indications for segment repositioning and redo-osteosynthesis increased after intraoperative imaging as compared to operator's clinical judgment before intraoperative imaging (95% confidence interval; p < .001 and p = .002 respectively). Suboptimal positioning and fixation of bone segments or osteosynthesis were more apparent with 3D imaging. In addition, some satisfactory cases were also revised for an optimal outcome. As a result, surgeons were prompted to more revisions than judged necessary without intraoperative imaging.

Video-urodynamics efficacy of sacral neuromodulation for neurogenic bladder guided by three-dimensional imaging CT and C-arm fluoroscopy: a single-center prospective study

To assess the efficacy of sacral neuromodulation (SNM) for neurogenic bladder (NB), guided by intraoperative three-dimensional imaging of sacral computed tomography (CT) and mobile C-arm fluoroscopy through video-urodynamics examination. We enrolled 52 patients with NB who underwent conservative treatment with poor results between September 2019 and June 2021 and prospectively underwent SNM guided by intraoperative three-dimensional imaging of sacral CT and mobile C-arm fluoroscopy. Video-urodynamics examination, voiding diary, quality of life questionnaire, overactive bladder symptom scale (OABSS) scoring, and bowel dysfunction exam were completed and recorded at baseline, at SNM testing, and at 6-month follow-up phases. Finally, we calculated the conversion rate from period I to period II, as well as the treatment efficiency and the occurrence of adverse events during the testing and follow-up phases. The testing phase of 52 NB patients was 18–60 days, with an average of (29.3 ± 8.0) days. Overall, 38 patients underwent SNM permanent electrode implantation, whose follow-up phase was 3–25 months, with an average of (11.9 ± 6.1) months. Compared with baseline, the voiding times, daily catheterization volume, quality of life score, OABSS score, bowel dysfunction score, maximum detrusor pressure before voiding, and residual urine volume decreased significantly in the testing phase. The daily voiding volume, functional bladder capacity, maximum urine flow rate, bladder compliance, and maximum cystometric capacity increased significantly in the testing phase. Besides, the voiding times, daily catheterization volume, quality of life score, OABSS score, bowel dysfunction score, maximum detrusor pressure before voiding, and residual urine volume decreased further from the testing to follow-up phase. Daily voiding volume, functional bladder capacity, maximum urine flow rate, bladder compliance, and maximum cystometric capacity increased further from testing to follow-up. At baseline, 10 ureteral units had vesicoureteral reflux (VUR), and 9 of them improved in the testing phase. Besides, there was 1 unit that further improved to no reflux during the follow-up phase. At baseline, 10 patients had detrusor overactivity (DO), and 8 of them improved in the testing phase. Besides, 1 patient’s symptoms further improved during the follow-up phase. At baseline, there were 35 patients with detrusor-bladder neck dyssynergia (DBND); 14 (40.0%) of them disappeared during the testing phase. Among 13 cases who had DBND in the testing phase, 6 (46.2%) disappeared during the follow-up phase. Of the 47 patients with detrusor-external sphincter dyssynergia (DESD) at baseline, 8 (17.0%) disappeared during the testing phase. Among 26 cases who had DESD in the testing phase, 6 (23.1%) disappeared during the follow-up phase. The effective rate of this study was 88.5% (46/52), and the conversion rate from phase I to phase II was 73.1% (38/52). Additionally, the efficacy in a short-term follow-up was stable. SNM guided by intraoperative three-dimensional imaging of sacral CT and mobile C-arm fluoroscopy is an effective and safe treatment option for NB in short time follow-up. It would be well improved in the bladder storage function, sphincter synergetic function and emptying efficiency by video-urodynamics examination in this study.Trial registration: Chinese Clinical Trial Registry. ChiCTR2100050290. Registered August 25 2021. http://www.chictr.org.cn/index.aspx.

Objective evaluation of volumetric changes during breast augmentation using intraoperative three-dimensional surface imaging

Breast volume estimation and implant size are crucial factors to achieve a symmetrical result in esthetic and reconstructive breast surgery. Although three-dimensional surface imaging (3DSI) has allowed for a better understanding of breast shape, size, and asymmetry during patient consultation, its use has been limited regarding intraoperative decision-making. To validate the intraoperative use of a portable hand-held 3D surface imaging device as an objective tool to assess volumetric changes during breast augmentation surgery. Patients receiving bilateral, submuscular breast augmentation were enrolled for this study. Intraoperative 3DSI was conducted using the Sense 3D scanner, allowing for digitalization of the operating field. Intraoperatively gauged volume changes caused by known implant volumes were compared with digital measurements calculated from 3D surface images of the operating field. Digital intraoperative breast volumes were compared to the pre- and postoperative Vectra XT reference system. Eighty individual breasts of 40 patients were successfully 3D imaged before incision and after wound closure. There was no significant difference between digital breast volumes by intraoperative and outpatient 3DSI. Intraoperative pre- to postoperative 3D breast volume change showed no significant difference to the known implant volume (p=0.124, mean deviation of 5.8±24.3mL and 2.0±9.0%). Our findings showed a high correlation regarding intraoperative digital breast volumetric changes. Intraoperative use of 3DSI yielded objective data during breast augmentation. This novel technique could beneficially impact future breast implant selection, especially in cases with breast asymmetry and the need for differently sized implants.

O-Arm Assisted Anterior Odontoid Screw Fixation in Type II and Rostral Type III Odontoid Fractures: Single Center Surgical Series of 50 Patients.

Accuracy of screw placement is one of the important factors necessary for adequate union in odontoid fractures with malposition rates as high as 27.2% with standard techniques. To evaluate efficacy of intraoperative O-arm assistance in improving accuracy of anterior odontoid screw placement and clinco-radiological outcome in type II and III odontoid fractures. In this retrospective study, surgery consisted of anterior odontoid screw fixation under intraoperative O-arm assistance over 5 years. Demographical, clinical, radiological, operative details and postoperative events were retrieved from hospital database and evaluated for fusion and surgical outcome. 50 patients (Mean age 34.6 years, SD 14.10, range: 7-70 years; 44 males and 6 females) with Type II and Type III odontoid fracture underwent O-arm assisted anterior screw placement. The mean interval between injury and surgery was 12 days (range 1-65 days). Mean operating time was 132.2 min ± SD 33.56 with average blood loss of 93 ml. ±SD 61.46. With our technique, accurate screw placement was achieved in 100% patients. At the mean follow-up of 26.4 month (SD13.75), overall acceptable fusion rate was 97.8% with non-union in 2.2% patients. Morbidity occurred in two patients; one patient developed fixation failure while other patient had nonunion which was managed with posterior C1-C2 arthrodesis. We had surgical mortality in one patient due to SAH. So overall our procedure was successful in 94% patients and among patients whose follow-up was available, acceptable fusion rates of 97.8% were achieved. We conclude that use of intraoperative three-dimensional imaging using O-arm for anterior odontoid screw fixation improves accuracy and leads to improved radiological and clinical outcomes. It further enables us to extend the indications of odontoid screw fixation to selected complex Type II and rostral Type III odontoid fractures.

Image Quality and Dose Comparison of 3 Mobile Intraoperative Three-Dimensional Imaging Systems in Spine Surgery

To evaluate radiation exposure and image quality (IQ) for 3 intraoperative imaging systems (Airo TruCT, Cios Spin, O-arm) using varying radiation dose settings in a single cadaveric model. Axial images of L4-5 instrumentation were obtained using 3 manufacturer dose protocols for each system. Measurements included scattered radiation dose, subjective and objective IQ, and estimates of patient effective dose (ED). Four images per system were selected at each dose level. Using the Likert scale (1= best, 5= worst), 9 reviewers rated the same 36 images. Objective IQ measures included the degree of streak artifacts (lines with incorrect data from metal objects) in each image. A composite figure of merit was derived based on ED and subjective and objective scores. The best subjective IQ scores were 1.44 (Cios Spin medium dose), 1.78 (Cios Spin high dose) and 2.22 (Airo TruCT low dose). The best objective IQ scores were 87.3 (Airo TruCT) and 89.1 (Cios Spin). ED low-dose results in mSv included 1.6 (Airo TruCT), 1.9 (Cios Spin), and 3.3 (O-arm). ED high-dose results in mSv included 4.6 (Cios Spin), 9.7 (Airo TruCT), and 9.9 (O-arm). Scatter radiation measurements for low dose in μGy included 21.9 (Cios Spin), 31.8 (Airo TruCT), and 33.9 (O-arm). Scatter radiation for high dose in μGy included 55.9 (Cios Spin), 104.5 (O-arm), and 200 (Airo TruCT). The best figure of merit score was for the Airo TruCT low dose, followed by Cios Spin medium dose and high dose. Selection of intraoperative imaging systems requires a greater understanding of the risks and benefits of radiation exposure and IQ.

Complex reconstructions in the facial and cranial regions

Posttraumatic reconstruction of the neurocranium and viscerocranium is an essential part of modern oral and maxillofacial surgery, in addition to oncological surgery, surgery of congenital craniofacial deformities and dental surgery. Due to the complex anatomy of the facial skull and significant esthetic and functional demands on its reconstruction, reconstructive trauma surgery in this area places the highest demands on the surgeon. This is all the more true if definitive craniomaxillofacial surgical treatment can sometimes only be performed with considerable delays for the benefit of other life-threatening injuries. In order to take these prerequisites into account, achievements of modern biomedical technology, such as intraoperative real-time navigation, computer-assisted planning and computer-assisted manufacturing (CAD/CAM) of patient-specific biomodels and implants, came up early for use in oral and maxillofacial surgery. In combination with intraoperative three-dimensional imaging, these methods result in atreatment pathway tailored to the individual patient, which is directly checked for quality at every step and thus ensures the best possible result for the patient. The use of these technologies extends far beyond the original indications in the area of orbital reconstruction and restoration of bony defects with simple geometry, such as skull defects. Nowadays, even the most complex pan-facial fractures can be restored esthetically and functionally by means of digitalized preliminary planning and individualized skull, orbital and zygomatic implants as well as total temporomandibular joint prostheses.

Present and Future Spinal Robotic and Enabling Technologies.

Enabling technologies include surgical planning software, computer-assisted navigation, intraoperative three-dimensional (3D) imaging, and robotic systems. Presently, these technologies are in various stages of refinement. Spinal robots in particular are currently limited to the positioning of an alignment guide for pedicle screw placement. Current generation spinal robots, therefore, play a more limited role in spinal surgery. In contrast to spinal robots, intraoperative imaging technology has been developed further, to a stage that allows accurate 3D spinal image acquisition that can be readily utilized for spinal navigation. The integration of these various technologies has the potential to maximize the safety, consistency, reliability, and efficacy of surgical procedures. To that end, the trend for manufacturers is to incorporate various enabling technologies into the spinal robotic systems. In the near-term, it is expected that integration of more advanced planning software and navigation will result in wider applicability and value. In the long-term, there are a variety of enabling technologies such as augmented reality that may be a component of spinal robots. This article reviews the features of currently available spinal robots and discusses the likely future advancements of robotic platforms in the near- and long-term.

Intraoperative real-time navigation and intraoperative three-dimensional imaging for patient-specific total temporomandibular joint replacement

Customized solutions for replacement of the temporomandibular joint (TMJ) along with surgical guides enable precise and fast transfer of the virtual plan to the patient. However, these guides lack information on screw vectors and length, and well-defined borders for bony resections towards the medial skull base. This retrospective study was performed to investigate the feasibility and benefit of real-time navigation and intraoperative three-dimensional imaging during total TMJ replacement (TJR), as well as patient clinical outcomes. Between 2016 and 2020, 26 customized prostheses were implanted in 21 patients either with or without real-time navigation and instrument tracking. The clinical, surgical, radiological, and navigational data were analysed. The accuracy of navigation registration with instrument tracking, precision of screw insertion, and implant and screw positions were analysed by fusion of the virtual plan and surgical outcome. Real-time navigation aided orientation during lateral skull base dissection and resection. However, the results of real-time navigation-aided drilling were inconclusive regarding vector and length control. At a mean 15.3±3.0 months of follow-up, average mouth opening had improved from 21.69±2.80mm to 36.40±1.25mm; the average pain score decreased from 6.18±0.74 to 1.06±0.52. Thus, intraoperative real-time navigation for TJR assists lateral skull base dissection and resection.

Intraoperative three-dimensional imaging in ankle syndesmotic reduction

Intraoperative three-dimensional imaging in ankle syndesmotic reduction

Intraoperative Three-dimensional Imaging of Ventricular Septal Defects in Children Using Epicardial Echocardiography: A Novel Approach

To assess the feasibility and accuracy of intraoperative three-dimensional (3D) epicardial en face images of ventricular septal defects (VSD) in children using the 3D transesophageal echocardiography (TEE) probe as an epicardial probe. This was a prospective nonrandomized blinded observational study. The study was conducted at a single tertiary cardiac care center. Fifty pediatric patients, weighing between 5.0 kg and 20 kg, who were scheduled for elective surgical closure of their VSDs, prospectively were recruited for this study. Epicardial 3D images were acquired using the full-volume mode. VSD location and size were determined from the 3D data sets using multiplanar reconstruction mode (QLAB 9) by a blinded investigator. The accuracy in terms of location and size was compared with surgical findings. In 50 study subjects, 54 VSDs were located by epicardial 3D echocardiography (3DE): 12 perimembranous, 17 inlet, eight muscular, 15 malaligned, and two outlet. Average image acquisition time was 4.96 (±1.47) minutes. Average image reconstruction time was 6.18 (±1.93) minutes. Good en face views of the VSD could be rendered in all patients (100% feasibility). The highest image quality was for perimembranous and malaligned VSDs. The location of VSD by 3DE corresponded precisely with surgical findings (100% accuracy). With linear regression analysis, excellent correlation was observed between the diameters measured by surgery and that measured by 3DE from the right ventricle side (r2 = 0.97, p < 0.001). The authors' study demonstrated that diagnostic quality 3D en face images of VSD can be obtained intraoperatively using 3D epicardial echocardiography. The short acquisition and reconstruction times make this technique clinically applicable.

Perforation Rate of Pedicle Screws Using Hybrid Operating Room Combined With Intraoperative Computed Tomography Navigation for Adolescent Idiopathic Scoliosis: Impact of Distance From the Reference Frame and Other Risk Factors.

Retrospective observational cohort study. Evaluate the perforation rate of pedicle screw (PS) insertion using a hybrid OR combined with intraoperative computed tomography (CT) navigation (hybrid navigation) for adolescent idiopathic scoliosis (AIS) and determine the predictors of misplacement specific to hybrid navigation. Hybrid navigation provides intraoperative three-dimensional fluoroscopic imaging of a quality similar to that of CT. Hybrid navigation is now being used in AIS treatment. However, few reports exist on the perforation rate and predictors of PS perforation using hybrid navigation for AIS. Thirty-eight consecutive patients (34 female and 4 male; mean age: 16.2 years) with AIS who had undergone PS fixation using hybrid navigation were analyzed. PS perforation was evaluated using intraoperative CT after PS insertion. The perforation rate for each level from the anchor reference frame (RF) was measured and compared. We examined for predictors of screw misplacement using baseline patient parameters, instrumented vertebral level, PS insertion order, and vertebral body distance from the RF. Eighteen major perforations (Grade 2 or Grade 3) were recorded among 531 screw insertions (3.4%). The major perforation rate did not increase remarkably until the distance from the RF was 5 vertebral bodies, after which it increased significantly (2.2% vs. 18.4%, P = 0.03). Thirteen patients experienced at least 1 perforation. The subjects with perforations were all female and significantly shorter than those without. Multivariate analysis revealed distance from the RF (+1 vertebra; odds ratio 1.44, P = 0.003) as a predictor of major perforation. The rate of major perforation after PS insertion using hybrid navigation for AIS was relatively low. However, no more than 7 vertebral bodies should be instrumented in a single CT scan to reduce the risk of major perforations. Special attention is also needed for female patients of shorter stature. 3.

Influence of syndesmotic injuries and posterior malleolar ankle fractures on fibula position in the ankle joint: a cadaveric study.

The aim of this study was to identify to what extent a dissection of the syndesmosis and an avulsed posterior edge of the tibia can change the tibiofibular diastasis and fibular rotation. Three-dimensional scans with a mobile C-arm of 22 cadaver legs were taken of the intact fibula, after dissection of the anterior part of the syndesmosis and the interosseous membrane, osteotomy of the posterior malleolus, and osteosynthesis. The tibiofibular diastasis as well as the angle of fibular rotation was identified in the four steps and the means compared to each other using a t test for paired samples. The distinction between the intact fibula vs. the osteotomy of the posterior tibia was 0.082 ± 0.332mm for the tibiofibular distance in the incisura tibiofibularis (p 0.261) and 0.046 ± 0.486 degrees for the angle of the fibular rotation (p 0.665). Neither the dissection of the syndesmosis nor the osteotomy of the posterior malleolus significantly influenced the position of the fibula in the incisura tibiofibularis in the cadaveric model. However, in the nonweight-bearing situation, a lesion of the syndesmotic complex might not be evident in intraoperative three-dimensional imaging.

Augmented Reality Surgical Navigation in Spine Surgery to Minimize Staff Radiation Exposure.

Prospective observational study. To assess staff and patient radiation exposure during augmented reality surgical navigation in spine surgery. Surgical navigation in combination with intraoperative three-dimensional imaging has been shown to significantly increase the clinical accuracy of pedicle screw placement. Although this technique may increase the total radiation exposure compared with fluoroscopy, the occupational exposure can be minimized, as navigation is radiation free and staff can be positioned behind protective shielding during three-dimensional imaging. The patient radiation exposure during treatment and verification of pedicle screw positions can also be reduced. Twenty patients undergoing spine surgery with pedicle screw placement were included in the study. The staff radiation exposure was measured using real-time active personnel dosimeters and was further compared with measurements using a reference dosimeter attached to the C-arm (i.e., a worst-case staff exposure situation). The patient radiation exposures were recorded, and effective doses (ED) were determined. The average staff exposure per procedure was 0.21 ± 0.06 μSv. The average staff-to-reference dose ratio per procedure was 0.05% and decreased to less than 0.01% after a few procedures had been performed. The average patient ED was 15.8 ± 1.8 mSv which mainly correlated with the number of vertebrae treated and the number of cone-beam computed tomography acquisitions performed. A low-dose protocol used for the final 10 procedures yielded a 32% ED reduction per spinal level treated. This study demonstrated significantly lower occupational doses compared with values reported in the literature. Real-time active personnel dosimeters contributed to a fast optimization and adoption of protective measures throughout the study. Even though our data include both cone-beam computed tomography for navigation planning and intraoperative screw placement verification, we find low patient radiation exposure levels compared with published data. 3.

Minimally Invasive Percutaneous C1-C2 Fixation Using an Intraoperative Three-Dimensional Imaging–Based Navigation System for Management of Odontoid Fractures

Odontoid fractures are the most common lesions of the upper cervical spine in patients >70 years old. These fractures are associated with frequent comorbidities, and minimally invasive techniques might have the potential to reduce postoperative complications while ensuring better precision. The aim of this study was to report an innovative technique and preliminary results of minimally invasive atlantoaxial fixation using a three-dimensional intraoperative navigation system and percutaneous approach. This retrospective study included 5 consecutive patients with an acute traumatic odontoid type II fracture managed using a percutaneous Harms fixation under three-dimensional intraoperative navigation guidance. C1 lateral mass screws and C2 isthmus screws were successfully placed in all patients. In all cases (100%), adequate screw positioning with no medial breach and no transverse foramen obstruction was observed. No intraoperative complications, such as injury of the vertebral artery, spinal nerve root, or spinal cord, occurred. None of the 5 patients received blood transfusion during or after the procedure. During the follow-up period (mean, 11.2 months; range, 5-16 months), 4 patients (80%) demonstrated a favorable clinical recovery, and only 1 patient required occasional medication for moderate pain. Mean radiation exposure was 4.83 mSV for each patient and 0 mSv for surgical staff. Minimally invasive atlantoaxial fixation using an intraoperative three-dimensional navigation system is a safe and effective alternative to the conventional approach that reduces postoperative morbidity.

Radiation dose and image quality comparison during spine surgery with two different, intraoperative 3D imaging navigation systems.

Careful protocol selection is required during intraoperative three‐dimensional (3D) imaging for spine surgery to manage patient radiation dose and achieve clinical image quality. Radiation dose and image quality of a Medtronic O‐arm commonly used during spine surgery, and a Philips hybrid operating room equipped with XperCT C‐arm 3D cone‐beam CT (hCBCT) are compared. The mobile O‐arm (mCBCT) offers three different radiation dose settings (low, standard, and high), for four different patient sizes (small, medium, large, and extra large). The patient's radiation dose rate is constant during the entire 3D scan. In contrast, C‐CBCT spine imaging uses three different field of views (27, 37, and 48 cm) using automatic exposure control (AEC) that modulates the patient's radiation dose rate during the 3D scan based on changing patient thickness. hCBCT uses additional x‐ray beam filtration. Small, medium, and large trunk phantoms designed to mimic spine and soft tissue were imaged to assess radiation dose and image quality of the two systems. The estimated measured “patient” dose for the small, medium, and large phantoms imaged by the mCBCT considering all the dose settings ranged from 9.4–27.6 mGy, 8.9–33.3 mGy, and 13.8–40.6 mGy, respectively. The “patient” dose values for the same phantoms imaged with hCBCT were 2.8–4.6 mGy, 5.7–10.0 mGy, and 11.0–15.2 mGy. The CNR for the small, medium, and large phantoms was 2.9 to 3.7, 2.0 to 3.0, and 2.5 to 2.6 times higher with the hCBCT system, respectively. Hounsfield unit accuracy, noise, and uniformity of hCBCT exceeded the performance of the mCBCT; spatial resolution was comparable. Added x‐ray beam filtration and AEC capability achieved clinical image quality for intraoperative spine surgery at reduced radiation dose to the patient in comparison to a reference O‐arm system without these capabilities.