Intraoperative Imaging Technologies Research Articles

Intraoperative in vivo confocal endomicroscopy of the glioma margin: performance assessment of image interpretation by neurosurgeon users.

Confocal laser endomicroscopy (CLE) is an intraoperative real-time cellular resolution imaging technology that images brain tumor histoarchitecture. Previously, we demonstrated that CLE images may be interpreted by neuropathologists to determine the presence of tumor infiltration at glioma margins. In this study, we assessed neurosurgeons' ability to interpret CLE images from glioma margins and compared their assessments to those of neuropathologists. In vivo CLE images acquired at the glioma margins that were previously reviewed by CLE-experienced neuropathologists were interpreted by four CLE-experienced neurosurgeons. A numerical scoring system from 0 to 5 and a dichotomous scoring system based on pathological features were used. Scores from assessments of hematoxylin and eosin (H&E)-stained sections and CLE images by neuropathologists from a previous study were used for comparison. Neurosurgeons' scores were compared to the H&E findings. The inter-rater agreement and diagnostic performance based on neurosurgeons' scores were calculated. The concordance between dichotomous and numerical scores was determined. In all, 4275 images from 56 glioma margin regions of interest (ROIs) were included in the analysis. With the numerical scoring system, the inter-rater agreement for neurosurgeons interpreting CLE images was moderate for all ROIs (mean agreement, 61%), which was significantly better than the inter-rater agreement for the neuropathologists (mean agreement, 48%) (p < 0.01). The inter-rater agreement for neurosurgeons using the dichotomous scoring system was 83%. The concordance between the numerical and dichotomous scoring systems was 93%. The overall sensitivity, specificity, positive predictive value, and negative predictive value were 78%, 32%, 62%, and 50%, respectively, using the numerical scoring system and 80%, 27%, 61%, and 48%, respectively, using the dichotomous scoring system. No statistically significant differences in diagnostic performance were found between the neurosurgeons and neuropathologists. Neurosurgeons' performance in interpreting CLE images was comparable to that of neuropathologists. These results suggest that CLE could be used as an intraoperative guidance tool with neurosurgeons interpreting the images with or without assistance of the neuropathologists. The dichotomous scoring system is robust yet simple and may streamline rapid, simultaneous interpretation of CLE images during imaging.

Intraoperative in vivo confocal laser endomicroscopy imaging at glioma margins: can we detect tumor infiltration?

Confocal laser endomicroscopy (CLE) is a US Food and Drug Administration-cleared intraoperative real-time fluorescence-based cellular resolution imaging technology that has been shown to image brain tumor histoarchitecture rapidly in vivo during neuro-oncological surgical procedures. An important goal for successful intraoperative implementation is in vivo use at the margins of infiltrating gliomas. However, CLE use at glioma margins has not been well studied. Matching in vivo CLE images and tissue biopsies acquired at glioma margin regions of interest (ROIs) were collected from 2 institutions. All images were reviewed by 4 neuropathologists experienced in CLE. A scoring system based on the pathological features was implemented to score CLE and H&E images from each ROI on a scale from 0 to 5. Based on the H&E scores, all ROIs were divided into a low tumor probability (LTP) group (scores 0-2) and a high tumor probability (HTP) group (scores 3-5). The concordance between CLE and H&E scores regarding tumor probability was determined. The intraclass correlation coefficient (ICC) and diagnostic performance were calculated. Fifty-six glioma margin ROIs were included for analysis. Interrater reliability of the scoring system was excellent when used for H&E images (ICC [95% CI] 0.91 [0.86-0.94]) and moderate when used for CLE images (ICC [95% CI] 0.69 [0.40-0.83]). The ICCs (95% CIs) of the LTP group (0.68 [0.40-0.83]) and HTP group (0.68 [0.39-0.83]) did not differ significantly. The concordance between CLE and H&E scores was 61.6%. The sensitivity and specificity values of the scoring system were 79% and 37%. The positive predictive value (PPV) and negative predictive value were 65% and 53%, respectively. Concordance, sensitivity, and PPV were greater in the HTP group than in the LTP group. Specificity was higher in the newly diagnosed group than in the recurrent group. CLE may detect tumor infiltration at glioma margins. However, it is not currently dependable, especially in scenarios where low probability of tumor infiltration is expected. The proposed scoring system has excellent intrinsic interrater reliability, but its interrater reliability is only moderate when used with CLE images. These results suggest that this technology requires further exploration as a method for consistent actionable intraoperative guidance with high dependability across the range of tumor margin scenarios. Specific-binding and/or tumor-specific fluorophores, a CLE image atlas, and a consensus guideline for image interpretation may help with the translational utility of CLE.

Using navigation in cases requiring upper cervical instrumentation in clinics without intraoperative imaging technology

Upper cervical spine surgery which requires instrumentation is a highly complicated procedure, both due to the presence of critical structures in the region and variable pedicle anatomy. Despite the widespread use of technological advances as intraoperative imaging and navigation technologies aimed at preventing screw malposition and injuries to the critical neural and vascular structures, there are only a few clinics capable of employing those technologies. In clinics lacking intraoperative imaging facilities that assist in the instrumentation of the upper cervical spine, navigation technology can be employed in both posterior and anterior approaches with the assistance of the technique described in this manuscript. This approach will not only decrease complication rates compared with the freehand method, but also considerably lower radiation exposure for both the patient and surgical team.

Comparison of intraoperative imaging guided versus microelectrode recording guided deep brain stimulation for Parkinson's disease: A meta-analysis

BackgroundTraditionally, most centers would use microelectrode recording (MER) to refine targeting in deep brain stimulation (DBS) surgery. In recent years, intraoperative imaging (IMG) guided DBS has become an alternative way to verify lead placement. Currently, there is still controversy surrounding the necessity of MER or IMG for DBS. This meta-analysis aims to explore lead accuracy, clinical efficacy and safety between IMG and MER guided DBS for Parkinson's disease (PD). MethodsPubMed, Embase, Web of Science, Cochrane Library were searched up to Mar, 2021 for studies reporting comparisons between IMG and MER guided DBS for PD. Subgroup analysis was conducted to assess effects of different IMG technology and DBS targeting site. ResultsSix studies, comprising of 478 patients were included in our analysis. The mean difference between the two implantation techniques in stereotactic accuracy, lead passes per trajectory, improvement% of Unified Parkinson's Disease Rating Scale part III and levodopa equivalent daily dose were −0.45 (95% confidence interval, CI=−1.11 to 0.20), −0.18 (95% CI=−0.41 to 0.06), 3.40 (95% CI=−5.36 to 12.16), and 5.00 (95% CI=−1.40 to 11.39), respectively. No significant differences were observed in each adverse event and operation/procedure time between the two implantation techniques. ConclusionsBoth IMG and MER guided DBS offered effective control of motor symptoms for PD. Besides, IMG guided is comparable to MER guided DBS, in terms of safety, accuracy and efficiency. It is recommended for each hospital to select DBS guidance technology based on available resources and equipment.

Comparison of intraoperative imaging guided versus microelectrode recording guided deep brain stimulation for Parkinson's disease: A meta-analysis

BackgroundTraditionally, most centers would use microelectrode recording (MER) to refine targeting in deep brain stimulation (DBS) surgery. In recent years, intraoperative imaging (IMG) guided DBS has become an alternative way to verify lead placement. Currently, there is still controversy surrounding the necessity of MER or IMG for DBS. This meta-analysis aims to explore lead accuracy, clinical efficacy and safety between IMG and MER guided DBS for Parkinson's disease (PD). MethodsPubMed, Embase, Web of Science, Cochrane Library were searched up to Mar, 2021 for studies reporting comparisons between IMG and MER guided DBS for PD. Subgroup analysis was conducted to assess effects of different IMG technology and DBS targeting site. ResultsSix studies, comprising of 478 patients were included in our analysis. The mean difference between the two implantation techniques in stereotactic accuracy, lead passes per trajectory, improvement% of Unified Parkinson's Disease Rating Scale part III and levodopa equivalent daily dose were −0.45 (95% confidence interval, CI=−1.11 to 0.20), −0.18 (95% CI=−0.41 to 0.06), 3.40 (95% CI=−5.36 to 12.16), and 5.00 (95% CI=−1.40 to 11.39), respectively. No significant differences were observed in each adverse event and operation/procedure time between the two implantation techniques. ConclusionsBoth IMG and MER guided DBS offered effective control of motor symptoms for PD. Besides, IMG guided is comparable to MER guided DBS, in terms of safety, accuracy and efficiency. It is recommended for each hospital to select DBS guidance technology based on available resources and equipment.

Choice of intraoperative ultrasound adjuncts for brain tumor surgery

BackgroundGliomas are among the most typical brain tumors tackled by neurosurgeons. During navigation for surgery of glioma brain tumors, preoperatively acquired static images may not be accurate due to shifts. Surgeons use intraoperative imaging technologies (2-Dimensional and navigated 3-Dimensional ultrasound) to assess and guide resections. This paper aims to precisely capture the importance of preoperative parameters to decide which type of ultrasound to be used for a particular surgery.MethodsThis paper proposes two bagging algorithms considering base classifier logistic regression and random forest. These algorithms are trained on different subsets of the original data set. The goodness of fit of Logistic regression-based bagging algorithms is established using hypothesis testing. Furthermore, the performance measures for random-forest-based bagging algorithms used are AUC under ROC and AUC under the precision-recall curve. We also present a composite model without compromising the explainability of the models.ResultsThese models were trained on the data of 350 patients who have undergone brain surgery from 2015 to 2020. The hypothesis test shows that a single parameter is sufficient instead of all three dimensions related to the tumor (p < 0.05). We observed that the choice of intraoperative ultrasound depends on the surgeon making a choice, and years of experience of the surgeon could be a surrogate for this dependence.ConclusionThis study suggests that neurosurgeons may not need to focus on a large set of preoperative parameters in order to decide on ultrasound. Moreover, it personalizes the use of a particular ultrasound option in surgery. This approach could potentially lead to better resource management and help healthcare institutions improve their decisions to make the surgery more effective.

Role of sentinel lymph node biopsy for oral squamous cell carcinoma: Current evidence and future challenges.

Sentinel lymph node biopsy (SLNB) has been used across oncological specialties for prognostication, staging, and identification of occult nodal metastasis. Recent studies demonstrated the potential clinical utility of SLNB in oral cavity squamous cell carcinoma (OCSCC). Elective neck dissection is the current standard of care in early management of OCSCC with depth of invasion greater than 2-4 mm; however, majority of patients ultimately do not have nodal disease on final pathology. SLNB is an alternative procedure widely adopted in early cancer management in many oncological subspecialities. Several considerations such as depth of invasion, nodal mapping, histopathology methods, operator variability, postoperative complications, and advancement in preoperative and intraoperative imaging technology can guide the appropriate application to SLNB in OCSCC. The aim of this review is to discuss the current evidence for SLNB in the treatment of early stage OCSCC, imaging technologies that support SLNB procedures, and studies that are currently underway.

Fluorescence-Guided Surgery and Novel Innovative Technologies for Improved Visualization in Pediatric Urology.

Fluorescence-guided surgery (FGS), three-dimensional (3D) imaging technologies, and other innovative devices are rapidly revolutionizing the field of urology, providing surgeons with powerful tools for a more complete understanding of patient-specific anatomy. Today, several new intraoperative imaging technologies and cutting-edge devices are available in adult urology to assist surgeons in delivering personalized interventions. Their applications are also gradually growing in general pediatric surgery, where the detailed visualization of normal and pathological structures has the potential to significantly minimize perioperative complications and improve surgical outcomes. In the field of pediatric urology, FGS, 3D reconstructions and printing technologies, augmented reality (AR) devices, contrast-enhanced ultrasound (CEUS), and intraoperative magnetic resonance imaging (iMRI) have been increasingly adopted for a more realistic understanding of the normal and abnormal anatomy, providing a valuable insight to deliver customized treatments in real time. This narrative review aims to illustrate the main applications of these new technologies and imaging devices in the clinical setting of pediatric urology by selecting, with a strict methodology, the most promising articles published in the international scientific literature on this topic. The purpose is to favor early adoption and stimulate more research on this topic for the benefit of children.

Intraoperative In Vivo Imaging Modalities in Head and Neck Cancer Surgical Margin Delineation: A Systematic Review.

Simple SummaryThe complete removal of cancerous tissue is an important predictor of patient outcomes after surgery, in particular for head and neck cancer surgery. Normally, surgical tissues are examined by a pathologist to determine whether a full removal of the cancer was performed. However, these analyses are often imperfect due to time constraints, limitations in frozen sections, and tissue orientation challenges. Newer intraoperative imaging techniques have shown great promise for increasing both the accuracy and efficiency of this process while in the operating room. This review summarizes and analyzes the current state of the literature on intraoperative imaging in determining cancer margins in head and neck cancers.Surgical margin status is one of the strongest prognosticators in predicting patient outcomes in head and neck cancer, yet head and neck surgeons continue to face challenges in the accurate detection of these margins with the current standard of care. Novel intraoperative imaging modalities have demonstrated great promise for potentially increasing the accuracy and efficiency in surgical margin delineation. In this current study, we collated and analyzed various intraoperative imaging modalities utilized in head and neck cancer to evaluate their use in discriminating malignant from healthy tissues. The authors conducted a systematic database search through PubMed/Medline, Web of Science, and EBSCOhost (CINAHL). Study screening and data extraction were performed and verified by the authors, and more studies were added through handsearching. Here, intraoperative imaging modalities are described, including optical coherence tomography, narrow band imaging, autofluorescence, and fluorescent-tagged probe techniques. Available sensitivities and specificities in delineating cancerous from healthy tissues ranged from 83.0% to 100.0% and 79.2% to 100.0%, respectively, across the different imaging modalities. Many of these initial studies are in small sample sizes, with methodological differences that preclude more extensive quantitative comparison. Thus, there is impetus for future larger studies examining and comparing the efficacy of these intraoperative imaging technologies.

Minimally Invasive Spine Surgery: An Overview

Spinal surgery is undergoing a major transformation toward a minimally invasive paradigm. This shift is being driven by multiple factors, including the need to address spinal problems in an older and sicker population, as well as changes in patient preferences and reimbursement patterns. Increasingly, minimally invasive surgical techniques are being used in place of traditional open approaches due to significant advancements and implementation of intraoperative imaging and navigation technologies. However, in some patients, due to specific anatomic or pathologic factors, minimally invasive techniques are not always possible. Numerous algorithms have been described, and additional efforts are underway to better optimize patient selection for minimally invasive spinal surgery (MISS) procedures in order to achieve optimal outcomes. Numerous unique MISS approaches and techniques have been described, and several have become fundamental. Investigators are evaluating combinations of MISS techniques to further enhance the surgical workflow, patient safety, and efficiency.

A Review of 3D Printing in Orthopedic Oncology

Over the past four decades, advancements in adjuvant treatments of bone sarcomas have catalyzed development of novel surgical technologies that continue to improve limb salvage surgeries. To date, these technologies have made limb salvage surgery the mainstay of treatment, while limb amputations became negligible. These advancements include pre-and intra-operative imaging technologies enabling accurate 3D-preoperative planning, and intraoperative patient-specific instruments allowing accurate execution of surgical plans. The introduction of customized 3D-printed porous titanium implants gave surgeons more freedom to retain surrounding healthy tissue and optimize reconstruction fit, thereby improving quality of life and reducing comorbidities post-operatively. Creating these custom implants has brought forth novel processes, materials and technologies and given rise to a new era in orthopedic oncology.

Clinical Intervention Using Focused Ultrasound (FUS) Stimulation of the Brain in Diverse Neurological Disorders.

Various surgical techniques and pharmaceutical treatments have been developed to improve the current technologies of treating brain diseases. Focused ultrasound (FUS) is a new brain stimulation modality that can exert a therapeutic effect on diseased brain cells, with this effect ranging from permanent ablation of the pathological neural circuit to transient excitatory/inhibitory modulation of the neural activity depending on the acoustic energy of choice. With the development of intraoperative imaging technology, FUS has become a clinically available noninvasive neurosurgical option with visual feedback. Over the past 10 years, FUS has shown enormous potential. It can deliver acoustic energy through the physical barrier of the brain and eliminate abnormal brain cells to treat patients with Parkinson's disease and essential tremor. In addition, FUS can help introduce potentially beneficial therapeutics at the exact brain region where they need to be, bypassing the brain's function barrier, which can be applied for a wide range of central nervous system disorders. In this review, we introduce the current FDA-approved clinical applications of FUS, ranging from thermal ablation to blood barrier opening, as well as the emerging applications of FUS in the context of pain control, epilepsy, and neuromodulation. We also discuss the expansion of future applications and challenges. Broadening FUS technologies requires a deep understanding of the effect of ultrasound when targeting various brain structures in diverse disease conditions in the context of skull interface, anatomical structure inside the brain, and pathology.

Device Profile of SonoVision™ Ultrasound System: Efficacy and Safety for Lateral Approach Spinal Surgery

Introduction Minimally invasive spinal surgeries rely heavily on imaging for localization of key anatomical structures. Current established modalities either do not provide adequate visualization of soft-tissue structures or do so in an indirect manner. Real-time integrated soft-tissue imaging will allow surgeons to accurately differentiate nerves, muscle, vasculature, and bone while simultaneously preventing excessive dissection of tissue and risk to patients. Areas Covered SonoVision™ is a novel imaging device able to meet the needs of intraoperative anatomical visualization. This review explains the mechanism of the device and summarizes the empirical support for its use. Multiple animal, cadaver, and human studies have been used to compile machine-learning training data and validate the system’s accuracy and usability through actual and simulated surgical scenarios. Expert Opinion SonoVision™ represents a significant improvement over current intraoperative imaging technology in terms of accuracy, efficiency, and ease of use. This system provides vital anatomical information that would otherwise be unavailable in an intuitive, real-time format. SonoVision™ may play an important role in improving outcomes in lateral approach spine surgery as well as making minimally invasive techniques more accessible to a wider range of surgeons. Article Highlights The direct lateral transpsoas approach for lumbar fusion has distinct advantages, but is associated with various complications, many of which are related to inadequate intraoperative imaging. There is a significant unmet need for real-time intraoperative soft-tissue imaging in spine surgery. The SonoVision™ ultrasound system utilizes machine-learning algorithms to provide real-time soft tissue imaging and differentiation for use during spine procedures. Early trials are promising with regard to SonoVision’s™ ability to meet needs for intraoperative soft-tissue imaging in lateral approach spine surgery.

The evolution of image guidance in robotic-assisted laparoscopic prostatectomy (RALP): a glimpse into the future.

To describe the innovative intraoperative technologies emerging to aid surgeons during minimally invasive robotic-assisted laparoscopic prostatectomy. We searched multiple electronic databases reporting on intraoperative imaging and navigation technologies, robotic surgery in combination with 3D modeling and 3D printing used during laparoscopic or robotic-assisted laparoscopic prostatectomy. Additional searches were conducted for articles that considered the role of artificial intelligence and machine learning and their application to robotic surgery. We excluded studies using intraoperative navigation technologies during open radical prostatectomy and studies considering technology to visualize lymph nodes. Intraoperative imaging using either transrectal ultrasonography or augmented reality was associated with a potential decrease in positive surgical margins rates. Improvements in detecting capsular involvement may be seen with augmented reality. The benefit, feasibility and applications of other imaging modalities such as 3D-printed models and optical imaging are discussed. The application of image-guided surgery and robotics has led to the development of promising new intraoperative imaging technologies such as augmented reality, fluorescence imaging, optical coherence tomography, confocal laser endomicroscopy and 3D printing. Currently challenges regarding tissue deformation and automatic tracking of prostate movements remain and there is a paucity in the literature supporting the use of these technologies. Urologic surgeons are encouraged to improve and test these advanced technologies in the clinical arena, preferably with comparative, randomized, trials.

Back to the OR of the Future: How Do We Make It a Good One?

Back to the OR of the Future: How Do We Make It a Good One?

Research progress on early diagnosis and prevention of anastomotic leak after rectal cancer surgery

Anastomotic leak is a common and serious complication after anterior rectal resection. Despite the continuous advancement of anastomotic instruments and surgical techniques, the incidence of anastomotic leak has not decreased significantly compared with the past. As more studies on the early diagnosis of anastomotic leak are published, postoperative risk factors of anastomotic leak, such as fever, time to first bowel movement, CT, C-reactive protein (CRP) and procalcitonin (PCT), matrix metalloproteinase-9, and other cytokines and biomarkers (IL-6, TNF-α, lactate, pH, urinary neopterin/creatinine ratio), provide a reference for surgeons to assess the risk and increase the possibility of early diagnosis of anastomotic leak. Nevertheless, preventing the occurrence of anastomotic leak is still the ultimate goal. For the prevention of anastomotic leak, intraoperative ICG fluorescence imaging technology provides a simple and safe objective method for surgeons to evaluate anastomotic perfusion. The diversion stoma may reduce the incidence of anastomotic leak. More and more evidence shows that drainage through the anal canal can reduce the incidence of anastomotic leak after rectal cancer, but whether different types of drainage catheters can clearly reduce the incidence of anastomotic leak still needs more evidence. In addition, there has not yet been a unified opinion on the retention time and location of the drainage catheter. At present, the research of anastomotic leak has not adopted a unified definition and the heterogeneity among related studies is still great. We still look forward to more high-quality multi-center large prospective and randomized controlled studies.

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.

A COMPARISON BETWEEN THE SPATIAL CONSIDERATIONS OF TECHNOLOGIES IN STANDARD AND HYBRID OPERATING ROOMS

The spatial considerations of operating rooms (ORs) are evolving frequently to keep pace with the scientific development of surgical procedures. The study utilizes a comparative approach to specify the differences between the dimensional and spatial considerations of equipping standard ORs that introduced significant technological improvements and hybrid ORs that integrate developed imaging equipment within the surgical environment. For example, operating tables offer a wide range of tilting angles and a radiolucent surface to pass-through x-rays in the hybrid OR, while the articulating arms of ceiling-mounted booms need enough space to move freely within the OR and suitable load capacity to hold various medical utilities. On the other hand, devices such as anesthesia and heart-lung machines are placed near the patient to provide the required medical support, while imaging equipment in hybrid ORs such as the C-arm require specific spatial considerations for ergonomic workflows. Ultimately, spatial considerations of hybrid ORs are similar to standard ORs with unique intraoperative imaging technologies.

Intraoperative imaging technology to maximise extent of resection for glioma: a network meta-analysis.

Multiple studies have identified the prognostic relevance of extent of resection in the management of glioma. Different intraoperative technologies have emerged in recent years with unknown comparative efficacy in optimising extent of resection. One previous Cochrane Review provided low- to very low-certainty evidence in single trial analyses and synthesis of results was not possible. The role of intraoperative technology in maximising extent of resection remains uncertain. Due to the multiple complementary technologies available, this research question is amenable to a network meta-analysis methodological approach. To establish the comparative effectiveness and risk profile of specific intraoperative imaging technologies using a network meta-analysis and to identify cost analyses and economic evaluations as part of a brief economic commentary. We searched CENTRAL (2020, Issue 5), MEDLINE via Ovid to May week 2 2020, and Embase via Ovid to 2020 week 20. We performed backward searching of all identified studies. We handsearched two journals, Neuro-oncology and the Journal of Neuro-oncology from 1990 to 2019 including all conference abstracts. Finally, we contacted recognised experts in neuro-oncology to identify any additional eligible studies and acquire information on ongoing randomised controlled trials (RCTs). RCTs evaluating people of all ages with presumed new or recurrent glial tumours (of any location or histology) from clinical examination and imaging (computed tomography (CT) or magnetic resonance imaging (MRI), or both). Additional imaging modalities (e.g. positron emission tomography, magnetic resonance spectroscopy) were not mandatory. Interventions included fluorescence-guided surgery, intraoperative ultrasound, neuronavigation (with or without additional image processing, e.g. tractography), and intraoperative MRI. Two review authors independently assessed the search results for relevance, undertook critical appraisal according to known guidelines, and extracted data using a prespecified pro forma. We identified four RCTs, using different intraoperative imaging technologies: intraoperative magnetic resonance imaging (iMRI) (2 trials, with 58 and 14 participants); fluorescence-guided surgery with 5-aminolevulinic acid (5-ALA) (1 trial, 322 participants); and neuronavigation (1 trial, 45 participants). We identified one ongoing trial assessing iMRI with a planned sample size of 304 participants for which results are expected to be published around winter 2020. We identified no published trials for intraoperative ultrasound. Network meta-analyses or traditional meta-analyses were not appropriate due to absence of homogeneous trials across imaging technologies. Of the included trials, there was notable heterogeneity in tumour location and imaging technologies utilised in control arms. There were significant concerns regarding risk of bias in all the included studies. One trial of iMRI found increased extent of resection (risk ratio (RR) for incomplete resection was 0.13, 95% confidence interval (CI) 0.02 to 0.96; 49 participants; very low-certainty evidence) and one trial of 5-ALA (RR for incomplete resection was 0.55, 95% CI 0.42 to 0.71; 270 participants; low-certainty evidence). The other trial assessing iMRI was stopped early after an unplanned interim analysis including 14 participants; therefore, the trial provided very low-quality evidence. The trial of neuronavigation provided insufficient data to evaluate the effects on extent of resection. Reporting of adverse events was incomplete and suggestive of significant reporting bias (very low-certainty evidence). Overall, the proportion of reported events was low in most trials and, therefore, issues with power to detect differences in outcomes that may or may not have been present. Survival outcomes were not adequately reported, although one trial reported no evidence of improvement in overall survival with 5-ALA (hazard ratio (HR) 0.82, 95% CI 0.62 to 1.07; 270 participants; low-certainty evidence). Data for quality of life were only available for one study and there was significant attrition bias (very low-certainty evidence). Intraoperative imaging technologies, specifically 5-ALA and iMRI, may be of benefit in maximising extent of resection in participants with high-grade glioma. However, this is based on low- to very low-certainty evidence. Therefore, the short- and long-term neurological effects are uncertain. Effects of image-guided surgery on overall survival, progression-free survival, and quality of life are unclear. Network and traditional meta-analyses were not possible due to the identified high risk of bias, heterogeneity, and small trials included in this review. A brief economic commentary found limited economic evidence for the equivocal use of iMRI compared with conventional surgery. In terms of costs, one non-systematic review of economic studies suggested that, compared with standard surgery, use of image-guided surgery has an uncertain effect on costs and that 5-ALA was more costly. Further research, including completion of ongoing trials of ultrasound-guided surgery, is needed.

Intraoperative axial patellar imaging: a new technique

Background: The medial patellofemoral ligament (MPFL) functions by providing patellar stability and preventing lateral displacement of the patella. Surgical fixation is commonly recommended for MPFL tears in the form of MPFL reconstruction via anatomic techniques. Intraoperative fluoroscopy is critical for identifying anatomical landmarks during surgery. Using the C-arm, both anteroposterior and lateral views are routinely obtained, leaving the surgeon blinded to the angle of approaching the patella. Thus, our team saw a need to develop a method to capture an axial-type view of the patella using available intraoperative imaging technology. Technique: After guide-pin insertion, fluoroscopy is positioned for an anteroposterior view. The knee is hyperflexed while externally rotating the tibia and ankle. The patient’s ankle is slightly below the edge of the operating table, causing the tibia to rotate out of view of the radiograph. The C-arm is angled cephalad, approximately 20 to 30 degrees with the C-arm lowered, the operating table is raised until the knee almost touches the C-arm. The angle of tibial rotation and knee flexion is adjusted to obtain a view that closely resembles is the Merchant view. Our axial patellofemoral fluoroscopic technique augments traditional anteroposterior and lateral views by providing increased accuracy of patellar fixation in relation to the patellofemoral joint. Discussion: As MPFL reconstruction and repair procedures become more common, there will be a desire to improve upon the technique and approach to the procedure. Anatomic positioning of the graft is the most important prognostic factor in determining success of the operation. To decrease complications, such as patellar fracture, accuracy of patellar fixation placement is paramount, and any measure to ensure proper graft placement should be utilized. Conclusions: Our technique established more precise guide-pin placement for the patellar tunnel. It also reduced time spent evaluating patellar fixation via additional orthogonal imaging. This could be associated with better outcomes and avoidance of common complications such as patellar fracture attributed to violation of the anterior cortex. Level of Evidence: Level V.