Intraoperative Modalities Research Articles

Generalisation capabilities of machine-learning algorithms for the detection of the subthalamic nucleus in micro-electrode recordings.

Micro-electrode recordings (MERs) are a key intra-operative modality used during deep brain stimulation (DBS) electrode implantation, which allow for a trained neurophysiologist to infer the anatomy in which the electrode is placed. As DBS targets are small, such inference is necessary to confirm that the electrode is correctly positioned. Recently, machine learning techniques have been used to augment the neurophysiologist's capability. The goal of this paper is to investigate the generalisability of these methods with respect to different clinical centres and training paradigms. Five deep learning algorithms for binary classification of MER signals have been implemented. Three databases from two different clinical centres have also been collected with differing size, acquisition hardware, and annotation protocol. Each algorithm has initially been trained on the largest database, then either directly tested or fine-tuned on the smaller databases in order to estimate their generalisability. As a reference, they have also been trained from scratch on the smaller databases as well in order to estimate the effect of the differing database sizes and annotation systems. Each network shows significantly reduced performance (on the order of a 6.5% to 16.0% reduction in balanced accuracy) when applied out-of-distribution. This reduction can be ameliorated through fine-tuning the network on the new database through transfer learning. Although, even for these small databases, it appears that retraining from scratch may still offer equivalent performance as fine-tuning with transfer learning. However, this is at the expense of significantly longer training times. Generalisability is an important criterion for the success of machine learning algorithms in clinic. We have demonstrated that a variety of recent machine learning algorithms for MER classification are negatively affected by domain shift, but that this can be quickly ameliorated through simple transfer learning procedures that can be readily performed for new centres.

1070 Muscle Mechanomyography (MMG) for Peripheral Nerve Monitoring During Lateral Lumbar Fusion: The New Kid on the Block?

INTRODUCTION: The lateral transpsoas approach has become a valuable minimally invasive option in lumbar spine surgery to achieve fusion, decompression, and deformity correction. However, femoral nerve injury during psoas retraction remains a significant concern, especially in the lower spinal levels. A newer alternative to electromyography (EMG), muscle mechanomyography (MMG) measures muscle fiber oscillation during contraction, providing a more specific and quantifiable response with a high signal to noise ratio. These characteristics make MMG an attractive option for intraoperative neuromonitoring (ION) in minimally invasive spine surgery. METHODS: Patients who underwent LLIF between 2018-2021 with MMG ION were included and compared to a historical cohot of patients who underwent LLIF from 2016-2021 with EMG ION. The femoral nerve palsy rate defined by ipsilateral thigh numbness, hip flexor, or quadricep weakness immediately post operatively were collected for both groups. Patients were re-evaluated at 3 month and 1 year follow up intervals. RESULTS: The rate of ipsilateral thigh numbness, hip flexor, and quadricep weakness at hospital discharge were 14.6% (6/41), 9.8% (4/41), and 7.3% (3/41) respectively for the MMG group, comparable to 14.8% (9/61), 23% (14/61), and 14.8% (9/61) observed in the EMG control group. Improvement in thigh numbness and leg weakness was observed for both groups at 3 month and 1 year follow up. No patients with leg weakness had less than antigravity strength. There were no statistically significant difference amongst patient demographics for both cohorts. CONCLUSIONS: In conclusion, MMG appears to be clinically equivalent to EMG as an intraoperative modality for femoral nerve monitoring in LLIF procedures. Further research is needed to evaluate the additional clinical advantages proposed by mechanomyography, such as low signal interference and quantifiable nerve localization.

Intraoperative indocyanine green fluorescence imaging to predict early hepatic arterial complications after liver transplantation.

The purpose of this study was to propose an innovative intraoperative criterion in a liver transplantation setting that would judge arterial flow abnormality that may lead to early hepatic arterial occlusion, that is, thrombosis or stenosis, when left untreated and to carry out reanastomosis. After liver graft implantation, and after ensuring that there is no abnormality on the Doppler ultrasound (qualitative and quantitative assessment), we intraoperatively injected indocyanine green dye (0.01mg/Kg), and we quantified the fluorescence signal at the graft pedicle using ImageJ software. From the obtained images of 89 adult patients transplanted in our center between September 2017 and April 2019, we constructed fluorescence intensity curves of the hepatic arterial signal and examined their relationship with the occurrence of early hepatic arterial occlusion (thrombosis or stenosis). Early hepatic arterial occlusion occurred in 7 patients (7.8%), including 3 thrombosis and 4 stenosis. Among various parameters of the flow intensity curve analyzed, the ratio of peak to plateau fluorescence intensity and the jagged wave pattern at the plateau phase were closely associated with this dreaded event. By combining the ratio of peak to plateau at 0.275 and a jagged wave, we best predicted the occurrence of early hepatic arterial occlusion and thrombosis, with sensitivity/specificity of 0.86/0.98 and 1.00/0.94, respectively. Through a simple composite parameter, the indocyanine green fluorescence imaging system is an additional and promising intraoperative modality for identifying recipients of transplant at high risk of developing early hepatic arterial occlusion. This tool could assist the surgeon in the decision to redo the anastomosis despite normal Doppler ultrasonography.

Uses of Smartphone Thermal Imaging in Perforator Flaps as a Versatile Intraoperative Tool: The Microsurgeon's Third Eye

IntroductionIn this study, we evaluate the versatility of smartphone thermal imaging technology as a valuable intraoperative modality in different stages of perforator flap surgery aiming to minimize the complications and achieve the best postoperative outcome. Patients and methodsThermography was performed in 20 perforator flaps in 20 patients at different surgical stages in three different ways to identify the most dominant perforator: first, by measuring the surface temperature of the skin; second, by using the dynamic infrared thermography technique; and third, by assessing the perfusion pattern when the flap was supplied by each perforator separately. Thermography was used to help in discarding the least perfused area of the flap. After microvascular anastomosis, the flap reheating pattern was evaluated. ResultsSeventeen free and three pedicled perforator flaps were included. Intraoperatively, each of the selected perforators had a corresponding hotspot. The perforator with the hottest hotpot, best rewarming, and provision of best flap perfusion on thermography was found clinically dominant. After microvascular anastomosis in free flaps, rapid rewarming was recorded in 15 cases. In two deep inferior epigastric perforator flaps, no rapid rewarming was observed. The pedicle was kinked in one case and there was a venous insufficiency in another case that required a cephalic turndown. All flaps showed good perfusion on thermography after inset. ConclusionSmartphone thermography has proven to be a valuable, cheap, rapidly employed, and objective tool not only for the design of perforator flaps, but also for the decision making intraoperatively to achieve the best surgical outcome.

Intraoperative Radiological Imaging: An Update on Modalities in Trauma and Orthopedic Surgery

Intraoperative radiological imaging plays a key role in the management algorithm of patient care. Different intraoperative modalities have applications in the diagnosis, treatment, and monitoring of patient affected by various medical or surgical conditions. Advances in technology, computer software, and integration of various radiological modalities have extended the applications of intraoperative imaging in health care. Intraoperative radiological imaging have evolved from the initial use of conventional fluoroscopy to current innovations of computed tomography (CT) such as three-dimensional cone-beam CT and magnetic resonance-based imaging. In fact, intraoperative imaging has become integral to most of trauma and orthopedic procedures. Apart from their role in diagnosis of a spectrum of orthopedic conditions like prosthetic joint infection, imaging systems assist orthopedic surgeons to perform minimally invasive procedures, improving patient safety and also enabling higher accuracy and lower revision rates. More importantly, advances in technologies are essential in safeguarding radiation safety regulations, thereby reducing the radiation dose to the patient and surgical team. Integration of various imaging technologies, improving quality of image acquisition, reduction of radiation dose, and seamless image transfer to allow decision-making process are crucial in the delivery of effective patient care.

Brachytherapy evolution as seen today.

While brachytherapy is the oldest form of radiation therapy, it is also a very exciting field from both physics and clinical perspectives. From the physics standpoint, brachytherapy dosimetry is largely being governed by the inverse-square law, leading to an unparalleled dose deposition kernel (dose emitted by a seed or single dwell position), even compared to proton or heavy-ion beamlets. There is slightly more dose beyond the central deposition point, but comparatively very little prior to it, that is, little or no entrance dose! It is easy to sum multiple dwell positions that cover a tumor, and the intensity can be modulated quite effectively using dwell times. From a clinical perspective, what sets brachytherapy apart from other intraoperative modalities (e.g., laser, radiofrequency, cryogenic) is our ability to precisely calculate the energy deposited across the relevant patient geometry, anticipate the effect from known dose-outcome relationships, and deliver that energy with exquisite control and selectively to the target volume while sparing organs at risks. This targeting ability has improved substantially over the last two decades. It is built upon key foundational elements, many of which stem from the research and development within our medical physics community. This article provides an overview of these elements that combine to make brachytherapy a successful and developing radiotherapy modality.

Review of Intraoperative Adjuncts for Maximal Safe Resection of Gliomas and Its Impact on Outcomes.

Maximal safe resection is the mainstay of treatment in the neurosurgical management of gliomas, and preserving functional integrity is linked to favorable outcomes. How these modalities differ in their effectiveness on the extent of resection (EOR), survival, and complications remains unknown. A systematic literature search was performed with the following inclusion criteria: published between 2005 and 2022, involving brain glioma surgery, and including one or a combination of intraoperative modalities: intraoperative magnetic resonance imaging (iMRI), awake/general anesthesia craniotomy mapping (AC/GA), fluorescence-guided imaging, or combined modalities. Of 525 articles, 464 were excluded and 61 articles were included, involving 5221 glioma patients, 7(11.4%) articles used iMRI, 21(36.8%) used cortical mapping, 15(24.5%) used 5-aminolevulinic acid (5-ALA) or fluorescein sodium, and 18(29.5%) used combined modalities. The heterogeneity in reporting the amount of surgical resection prevented further analysis. Progression-free survival/overall survival (PFS/OS) were reported in 18/61(29.5%) articles, while complications and permanent disability were reported in 38/61(62.2%) articles. The reviewed studies demonstrate that intraoperative adjuncts such as iMRI, AC/GA mapping, fluorescence-guided imaging, and a combination of these modalities improve EOR. However, PFS/OS were underreported. Combining multiple intraoperative modalities seems to have the highest effect compared to each adjunct alone.

Comparison of image registration methods for combining laparoscopic video and spectral image data

Laparoscopic procedures can be assisted by intraoperative modalities, such as quantitative perfusion imaging based on fluorescence or hyperspectral data. If these modalities are not available at video frame rate, fast image registration is needed for the visualization in augmented reality. Three feature-based algorithms and one pre-trained deep homography neural network (DH-NN) were tested for single and multi-homography estimation. Fine-tuning was used to bridge the domain gap of the DH-NN for non-rigid registration of laparoscopic images. The methods were validated on two datasets: an open-source record of 750 manually annotated laparoscopic images, presented in this work, and in-vivo data from a novel laparoscopic hyperspectral imaging system. All feature-based single homography methods outperformed the fine-tuned DH-NN in terms of reprojection error, Structural Similarity Index Measure, and processing time. The feature detector and descriptor ORB1000 enabled video-rate registration of laparoscopic images on standard hardware with submillimeter accuracy.

Can indocyanine green during laparoscopic sleeve gastrectomy be considered a new intraoperative modality for leak testing?

BackgroundIndocyanine green (ICG) when injected intravenously into the bloodstream allows us to show stomach vascularity in real time. The aim of our study was to observe the preliminary results of the application of indocyanine green fluorescence (IGF) during laparoscopic sleeve gastrectomy (LSG) in our center and how the perfusion of the staple line of the stomach affects the onset of fistula.Materials and methods82 patients underwent LSG with ICG fluorescence angiography at our center from January 2020 to December 2021. 5 ml of ICG was injected intravenously to identify the blood supply of the stomach, carefully assessing the angle of His.ResultsIn the ICG-tested LSG, we recorded adequate perfusion in all patients but one: the leakage rate was 1.2%. This data is inferior to the non-tested patients’ group.ConclusionIntraoperative ICG testing may be helpful in determining which patients are at an increased risk for leakage but there are multiple factors contribute to the pathophysiology and the incidence of gastric fistula not only the perfusion.Trial registration Retrospectively registrated

Intraoperative MR Imaging during Glioma Resection.

One of the major issues in the surgical treatment of gliomas is the concern about maximizing the extent of resection while minimizing neurological impairment. Thus, surgical planning by carefully observing the relationship between the glioma infiltration area and eloquent area of the connecting fibers is crucial. Neurosurgeons usually detect an eloquent area by functional MRI and identify a connecting fiber by diffusion tensor imaging. However, during surgery, the accuracy of neuronavigation can be decreased due to brain shift, but the positional information may be updated by intraoperative MRI and the next steps can be planned accordingly. In addition, various intraoperative modalities may be used to guide surgery, including neurophysiological monitoring that provides real-time information (e.g., awake surgery, motor-evoked potentials, and sensory evoked potential); photodynamic diagnosis, which can identify high-grade glioma cells; and other imaging techniques that provide anatomical information during the surgery. In this review, we present the historical and current context of the intraoperative MRI and some related approaches for an audience active in the technical, clinical, and research areas of radiology, as well as mention important aspects regarding safety and types of devices.

Methods of identification of parathyroid glands in thyroid surgery: A literature review

Intra-operative identification and preservation of parathyroid glands is an important but challenging aspect of thyroid surgery. Failure to do so may lead to transient or permanent hypocalcaemia, where the latter represents a serious complication causing life-long morbidity. It would be beneficial, therefore, if a simple and reliable modality can be developed to assist in the identification of parathyroid glands intra-operatively. The aim of this literature review is to provide an overview of intra-operative modalities used to identify parathyroid glands with a particular focus on near-infrared autofluorescence (NIRAF). Twenty-seven studies were considered relevant in this literature review. Several modalities have been used to aid parathyroid gland identification, including Raman spectroscopy, indocyanine green angiography, and NIRAF. NIRAF technology allows parathyroid glands to spontaneously give off light (autofluorescence) when exposed to near-infrared light at a wavelength of 785 nm, creating a contrast between tissues to allow intra-operative differentiation. Studies utilising NIRAF technology were able to identify 76.3%-100% of parathyroid glands intra-operatively. Furthermore, two randomised controlled trials comparing NIRAF and white light showed that the use of NIRAF was able to significantly increase the mean number of parathyroid glands detected and reduce the incidence of post-operative hypocalcaemia. NIRAF is an emerging tool that has been shown to increase the number of intra-operative parathyroid gland identification and reduce the rate of post-operative hypocalcaemia in a safe and reproducible manner. Future trials are needed to evaluate the real-life impact of NIRAF technology in outcomes of patients following thyroid surgery.

Integrated multi-modality image-guided navigation for neurosurgery: open-source software platform using state-of-the-art clinical hardware

PurposeImage-guided surgery (IGS) is an integral part of modern neuro-oncology surgery. Navigated ultrasound provides the surgeon with reconstructed views of ultrasound data, but no commercial system presently permits its integration with other essential non-imaging-based intraoperative monitoring modalities such as intraoperative neuromonitoring. Such a system would be particularly useful in skull base neurosurgery.MethodsWe established functional and technical requirements of an integrated multi-modality IGS system tailored for skull base surgery with the ability to incorporate: (1) preoperative MRI data and associated 3D volume reconstructions, (2) real-time intraoperative neurophysiological data and (3) live reconstructed 3D ultrasound. We created an open-source software platform to integrate with readily available commercial hardware. We tested the accuracy of the system’s ultrasound navigation and reconstruction using a polyvinyl alcohol phantom model and simulated the use of the complete navigation system in a clinical operating room using a patient-specific phantom model.ResultsExperimental validation of the system’s navigated ultrasound component demonstrated accuracy of <4.5,hbox {mm} and a frame rate of 25 frames per second. Clinical simulation confirmed that system assembly was straightforward, could be achieved in a clinically acceptable time of <15,hbox {min} and performed with a clinically acceptable level of accuracy.ConclusionWe present an integrated open-source research platform for multi-modality IGS. The present prototype system was tailored for neurosurgery and met all minimum design requirements focused on skull base surgery. Future work aims to optimise the system further by addressing the remaining target requirements.

Integration of Different Intraoperative Ultrasound Modalities in Meningioma Surgery: A 4-Step Approach

Integration of Different Intraoperative Ultrasound Modalities in Meningioma Surgery: A 4-Step Approach

Diagnostic value of Sestamibi Scan in the preoperative localization of parathyroid lesions in patients with primary hyperparathyroidism.

Abstract Introduction: Preoperative localization modalities for patients with primary hyperparathyroidism today play an important role in clinical decision making, surgical procedure, and the prognosis of patients. One of the most common preoperative imaging modalities is the sestamibi scan labeled with Technetium-99m, which is capable of determining the location of parathyroid lesions in primary hyperparathyroidism patients with high sensitivity. Methods: In this cross-sectional study, 25 patients with primary hyperparathyroidism, referred to endocrine clinic of Tabriz University of Medical Siences during 2016-2018 were enrolled. All patients underwent a preoperative Sestamibi scan. Comparing the results of the scan with the surgical findings as a standard gold method for diagnosis, the diagnostic value of the scan was evaluated for the localization of parathyroid lesions. Results: According to the items observed in surgery and pathologic findings, the sensitivity of Sestamibi scan for the localization of parathyroid lesions was 84.6%. Specificity and positive predictive value and negative predictive value were 95.6%, 89.6%, and 94.8%, respectively. A significant relationship was observed between the type of lesion and the sensitivity of Sestamibi scan (p=0.002). Conclusion: Sestamibi scan has high sensitivity and diagnostic and therapeutic value for patients with primary hyperparathyroidism. However, the existence of other pre- and intraoperative localization modalities, at the request of surgeons, is useful and warranted to reduce the rate of recurrent surgery as well as to minimize false negatives.

Visualization of White Matter Fiber Tracts of Brain Tissue Sections With Wide-Field Imaging Mueller Polarimetry.

Identification of white matter fiber tracts of the brain is crucial for delineating the tumor border during neurosurgery. A custom-built Mueller polarimeter was used in reflection configuration for the wide-field imaging of thick sections of fixed human brain and fresh calf brain. The maps of the azimuth of the fast optical axis of linear birefringent medium reconstructed from the experimental Mueller matrix images of the specimen by applying a non-linear data compression algorithm showed a strong correlation with the silver-stained sample histology image, which is the gold standard for ex-vivo brain fiber tract visualization. The polarimetric maps of fresh calf brain tissue demonstrated the same trends in the depolarization, the scalar retardance and the azimuth of the fast optical axis as seen in fixed human brain tissue. Thus, label-free imaging Mueller polarimetry shows promise as an efficient intra-operative modality for the visualization of healthy brain white matter fiber tracts, which could improve the accuracy of tumor border detection and, ultimately, patient outcomes.

The use of bi-pedicled DIEP flap for unilateral breast reconstruction: a 5-year retrospective study

The deep inferior epigastric perforator (DIEP) flap is currently the flap of choice for autologous breast reconstruction. When the amount of tissue transferred needs to be maximised, a bi-pedicled DIEP flap allows harvesting the entire lower abdomen. A retrospective analysis was conducted including patients who had unilateral breast reconstruction with bi-pedicled DIEP flaps between January 2013 and December 2017. Demographic information, operation notes and post-operative course were reviewed. Mann-Whitney-Wilcoxon and Fischer’s exact tests were used to look for a statistically significant association between complications and intra-operative modalities. Forty-four cases were reviewed. Half of these patients underwent delayed breast reconstructions, 40.9% underwent immediate reconstructions and 10% were salvage cases. The majority of the cases (52.3%) had an initial anastomosis of the secondary pedicle to either a side branch (38.6%) or the superior continuity (13.6%) of the primary pedicle (intra-flap anastomosis). Twenty-seven percent of the intra-flap arterial anastomoses were performed using vessel couplers. The remaining 47.7% of the cohort had anastomoses of both pedicles to the internal mammary (IM) vessels anterogradely and retrogradely. There were no flap failures. The cases in which both pedicles were anastomosed with IM vessels had an overall higher complications rate, but were not related to flap failures or anastomotic issues. Intra-flap anastomosis on the other hand is a reliable alternative including the possibility of vessel coupler application to smaller arteries of this approach. In our experience, bi-pedicled DIEP flaps are a safe alternative for unilateral breast reconstruction when the amount of harvested tissue needs to be maximised. Level of evidence: Level III, therapeutic study.

Advances in image enhancement for sarcoma surgery.

The recurrence rate of soft tissue and bone sarcomas strongly correlates to the status of the surgical margin after excision, yet excessive removal of tissue may lead to distinct, otherwise avoidable morbidity. Therefore, adequate margination of sarcomas both pre- and intra-operatively is a clinical necessity that has not yet fully been met. Current guidance for soft-tissue sarcomas recommends an ultrasound scan followed by magnetic resonance imaging (MRI). For bone sarcomas, two plane radiographs are required, followed similarly by an MRI scan. The introduction of more precise imaging modalities may reduce the morbidity associated with sarcoma surgery; the PET-CT and PET-MRI approaches in particular demonstrating high clinical efficacy. Despite advancements in the accuracy in pre-operative imaging, translation of an image to surgical margins is difficult, regularly resulting in wider resection margins than required. For soft tissue sarcomas there is currently no standard technique for image guided resections, while for bone sarcomas fluoroscopy may be used, however margins are not easily discernible during the surgical procedure. Near infra-red (NIR) fluorescence guided surgery offers an intra-operative modality through which complete tumour resection with adequate tumour-free margins may be achieved, while simultaneously minimising surgical morbidity. NIR imaging presents a potentially valuable adjunct to sarcoma surgery. Early reports indicate that it may be able to provide the surgeon with helpful information on anatomy, perfusion, lymphatic drainage, tumour margins and metastases. The use of NIR fluorochromes have also been demonstrated to be well tolerated by patients. However, prior to widespread implementation, studies related to cost-effectiveness and the development of protocols are essential. Nevertheless, NIR imaging may become ubiquitous in the future, carrying the potential to transform the surgical management of sarcoma.

Assessment of Lung Recruitment by Ultrasound in Patient Undergoing Upper Abdominal Surgery

Atelectasis and poorly ventilated lung areas are negative consequences of general anesthesia observed in adult as well as in children. The reported incidence of this anesthesia-induced atelectasis is high and comes from 83 % to almost 100 %. The diagnosis of this entity is difficult to do at the bedside; they are commonly small and mostly invisible to standard chest X-ray images. Several methods have been suggested to reduce the impact of atelectasis during surgery. However, few intraoperative modalities for the diagnosis and monitoring of atelectasis are available. Lung ultrasound imaging is a promising non-invasive, non-radiant, portable and easy to use tool that as yet to be studied in the intraoperative setting. 80 adult patients with different ventilation strategies were divided into four groups, 20 patients were included in the 1st group conventional ventilation with large tidal volume 10ml/kg, with FiO2 1 with neither PEEP nor recruitment, 20 patients were included in the 2nd group conventional ventilation with large tidal volume 10ml/kg, with FiO2 0.6 with neither PEEP nor recruitment, 20 patients were included in the 3rd group protective lung ventilation with tidal volume 6ml/kg, with FiO2 1 plus recruitment and PEEP, and 20 patients were included in the 4th group protective lung ventilation with tidal volume 6ml/kg, with FiO2 0.6 plus recruitment and PEEP comparative study between lung ultrasound atelectasis score (LUS), the median and Interquartile range (IQR) of lung ultrasound score was done. There was statistically significant difference between the four groups of the study at all times except for baseline reading (P

Intraoperative glycemic control in patients undergoing Orthotopic liver transplant: a single center prospective randomized study

BackgroundPerioperative hyperglycemia is associated with poor outcomes yet evidence to guide intraoperative goals and treatment modalities during non-cardiac surgery are lacking. End-stage liver disease is associated with altered glucose homeostasis; patients undergoing liver transplantation display huge fluctuations in blood glucose (BG) and represent a population of great interest. Here, we conduct a randomized trial to compare the effects of strict versus conventional glycemic control during orthotopic liver transplant (OLT).MethodsFollowing approval by the Institutional Review Board of the University of Michigan Medical School and informed consent, 100 adult patients undergoing OLT were recruited. Patients were randomized to either strict (target BG 80–120 mg/dL) or conventional (target BG 180–200 mg/dL) BG control with block randomization for diabetic and nondiabetic patients. The primary outcomes measured were 1-year patient and graft survival assessed on an intention to treat basis. Graft survival is defined as death or needing re-transplant (www.unos.org). Three and 5-year patient and graft survival, infectious and biliary complications were measured as secondary outcomes. Data were examined using univariate methods and Kaplan-Meir survival analysis. A sensitivity analysis was performed to compare patients with a mean BG of ≤120 mg/dL and those > 120 mg/dL regardless of treatment group.ResultsThere was no statistically significant difference in patient survival between conventional and strict control respectively;1 year, 88% vs 88% (p-0.99), 3 years, 86% vs 84% (p- 0.77), 5 years, 82% vs 78. % (p-0.36). Graft survival was not different between conventional and strict control groups at 1 year, 88% vs 84% (p-0.56), 3 years 82% vs 76% (p-0.46), 5 years 78% vs 70% (p-0.362).ConclusionThere was no difference in patient or graft survival between intraoperative strict and conventional glycemic control during OLT.Trial registrationClinical trial number and registry: www.clinicaltrials.gov NCT00780026. This trial was retrospectively registered on 10/22/2008.

Reliability of intra-operative frozen section study in revision of infected hip arthroplasty

IntroductionFrozen sections are extensively used to help in the diagnosis of periprosthetic joint infection during revision hip arthroplasty, though there are insufficient data in relation to its usefulness.MethodsTwenty-one patients with infected hip arthroplasties were operated in the form of one or two-staged revision hip arthroplasties. A frozen section was obtained intra-operatively and > 5 PMN’s/ HPF was considered as a positive indicator of infection. If the frozen section was reported negative (≤5 PMN’s/HPF), the revision prosthesis was implanted after a thorough debridement and a wash. If the frozen section was reported as positive, post the debridement; a non-articulating antibiotic-loaded cement spacer was implanted for 8 weeks, supplemented with 3 weeks of intravenous antibiotics and 3 weeks of oral antibiotics. This was followed by an antibiotic-free interval of 2 weeks. The patient was taken up for a revision surgery once the frozen section study was negative (≤5 PMN’s/HPF). The patients were followed up for a minimum of 1 year to a maximum of 2 years after the revision for any evidence of infection (assessed clinically, serologically, and radiologically).ResultsFrozen section analysis of PMNs per high power field had a 100% specificity in our patients in detecting periprosthetic joint infection.ConclusionFrozen section study is a safe, rapid, cheap and reliable intra-operative modality to diagnose periprosthetic joint infection.