A growing body of evidence demonstrates that excursions of BP below or above the limits of cerebral blood flow autoregulation are associated with complications in patients with neurological injury or ...for those undergoing cardiac surgery. Moreover, recent evidence suggests that maintaining MAP above the lower limit of cerebral autoregulation during cardiopulmonary bypass reduces the frequency of postoperative delirium and is associated with improved memory 1 month after surgery. Continuous measurement of BP in relation to cerebral autoregulation limits using a virtual patient monitoring platform processing near-infrared spectroscopy digital signals offers the hope of bringing this application to the bedside.
Abstract Background Integration of molecular imaging and in particular intraoperative image guidance is expected to improve the surgical accuracy of laparoscopic lymph node (LN) dissection. Objective ...To show the applicability of combining preoperative, intraoperative, and postoperative sentinel node imaging using an integrated diagnostic approach based on an imaging agent that is both radioactive and fluorescent. Design, setting, and participants Before surgery, multimodal indocyanine green (ICG)-99m Tc-NanoColl was injected into the prostate. Subsequent lymphoscintigraphy and single-photon emission computed tomography/computed tomography (SPECT/CT) imaging of pelvic nodes was performed to determine the location of the sentinel lymph nodes (SLNs) preoperatively. During the surgical procedure a fluorescence laparoscope, optimized for detection in the near infrared range, was used to visualize the nodes identified on SPECT/CT. Eleven patients scheduled for robot-assisted laparoscopic prostatectomy (RALP) with an increased risk of nodal metastasis, based on Memorial Sloan-Kettering Cancer Center/Kattan nomogram estimation, participated in a pilot assessment (N09IGF). Surgical procedure Patients underwent RALP with LN dissection for prostate cancer. Measurements Radioactive and fluorescent signals were monitored using different modalities, and the correlation between the two types of signals was studied. The location of preoperatively detected SLNs was documented. Results and limitations Preoperatively, SLNs were identified by SPECT/CT, and the multimodal nature of the imaging agent also enabled intraoperative detection via fluorescence imaging. Fluorescence particularly improved surgical guidance in areas with a high radioactive background signal such as the injection site. Ex vivo analysis revealed a strong correlation between the radioactive and fluorescent content in the excised LNs. Fluorescence detection is limited by the severe tissue attenuation of the signal. Therefore, radio guidance to the areas of interest is still desirable. Conclusions Initial data indicate that multimodal ICG-99m Tc-NanoColloid, in combination with a laparoscopic fluorescence laparoscope, can be used to facilitate and optimize dissection of SLNs during RALP procedures.
The metastatic status of regional lymph nodes is the most relevant prognostic factor in breast cancer, melanoma, and other solid organ tumors with a lymphatic spread. The current gold standard for ...detection and targeted excision of the sentinel lymph node is preoperative lymphoscintigraphy with technetium Tc 99m. Because of the worldwide shortage of technetium Tc 99m, physicians are looking for nonradioactive dyes for sentinel lymph node labeling. Based on several retrospective studies, the fluorescent dye indocyanine green is considered a possible alternative to technetium Tc 99m.
To analyze the feasibility and clinical benefit of intraoperative near infrared fluorescence sentinel lymph node excision (SLNE) compared with standard technetium Tc 99m-guided SLNE using malignant melanoma in which SLNE is firmly established.
Analysis of a prospective clinical trial at the Skin Cancer Center, University Hospital Essen. Eighty patients with malignant melanoma on the trunk or extremities (upper and lower) who were scheduled to undergo SLNE were included in this study from January 1, 2013, to June 27, 2014.
Concordance of preoperative and intraoperative sentinel lymph node detection rates.
During the study period, 80 patients were operated on with an additional intraoperative application of a near infrared fluorescent dye. In these 80 surgical procedures, 147 SLNs were excised. Detection of a technetium Tc 99m-marked SLN before surgery was possible in all cases. Intraoperative visualization of the SLN by indocyanine green before skin incision was successful in only 17 of 80 patients (21%). The number of SLNs identified using the near infrared fluorescence technique in the operative site after skin incision and initial tissue preparation was 141 of 147 (96%).
Among patients in whom the lymph node basin cannot be predicted correctly (eg, in cutaneous melanoma on the trunk), the use of indocyanine green for SLN detection is severely limited compared with SLNE using standard technique guided by technetium Tc 99m. Therefore, SLNE with the use of radiocolloid, followed if possible by single-photon emission computed tomography, remains the gold standard.
German Clinical Trials Register identifier DRKS00004619.
•There is a need for prospective research to optimize muscle recorded transcranial electrical stimulation motor evoked potential (mTc-MEPs) stimulation parameters with the use of total intravenous ...anesthesia.•Different mTc-MEP monitoring methods require different optimal stimulation parameters.•No studies were included that optimized stimulation parameters for D-wave monitoring.
The aim of this systematic review was to find the optimal stimulation parameters for muscle recorded transcranial electrical stimulation motor evoked potential (mTc-MEP) and D-wave monitoring during spinal cord monitoring.
A PRISMA systematic search in Medline and EMBASE and a QUADAS-2 quality evaluation was performed to identify studies that compared stimulation parameters consisting of stimulation location, number of pulses, pulse duration, interstimulus interval, double train (DTS) or recurrent train stimulation (RTS) and intertrain interval (ITI) for performing mTc-MEP and D-wave monitoring. Only studies that used total intravenous anaesthesia (TIVA) were included.
Ten studies that compared stimulation parameters for performing mTc-MEP monitoring (stimulation location n = 4, number of pulses n = 2, pulse duration n = 1, interstimulus interval n = 4, DTS n = 1, RTS n = 2, ITI n = 2) were included. No studies compared stimulation parameters (stimulation location and pulse duration) for performing D-wave monitoring.
Few studies examined the optimal stimulation parameters for monitoring mTc-MEPs and no studies were included for D-wave monitoring. There is a need for prospective research to investigate the optimal stimulation parameters for mTc-MEP with the use of TIVA and D-wave monitoring.
For mTc-MEP monitoring, a table is provided in which the recommended stimulation parameters are stated.
Intraoperative hypotension (IOH) is a common side effect of general anesthesia and has been reported to be associated with adverse perioperative outcomes. These associations were found using ...different definitions for IOH. It is unknown whether the incidences of IOH found with those different definitions are comparable. The authors aimed to describe the relation between the chosen definition and incidence of IOH.
First, a systematic literature search was performed to identify recent definitions of IOH that have been used in the anesthesia literature. Subsequently, these definitions were applied to a cohort of 15,509 consecutive adult patients undergoing noncardiac surgery during general anesthesia. The incidence of IOH according to the different threshold values was calculated, and the effect of a defined minimal duration of a hypotensive episode was studied.
Many different definitions of IOH were found. When applied to a cohort of patients, these different definitions resulted in different IOH incidences. Any episode of systolic blood pressure below 80 mmHg was found in 41% of the patients, whereas 93% of the patients had at least one episode of systolic blood pressure more than 20% below baseline. Both definitions are frequently used in the literature. The relation between threshold values from the literature and IOH incidence shows an S-shaped cumulative incidence curve, with occurrence frequencies of IOH varying from 5% to 99%.
There is no widely accepted definition of IOH. With varying definitions, many different incidences can be reproduced. This might have implications for previously described associations between IOH and adverse outcomes.
Background Intraoperative evaluation of successful pancreatic tumor ablation using irreversible electroporation (IRE) is difficult secondary to lack of visual confirmation. The IRE generator provides ...feedback by reporting current (amperage), which can be used to calculate changes in tumor tissue resistance. The purpose of the study was to determine if resistance can be used to predict successful tumor ablation during IRE for pancreatic cancers. Study Design All patients undergoing pancreatic IRE from March 2010 to December 2012 were evaluated using a prospective database. Intraoperative information, including change in tumor resistance during ablation and slope of the resistance curve, were used to evaluate effectiveness of tumor ablation in terms of local failure or recurrence (LFR) and disease-free survival (DFS). Results A total of 65 patients underwent IRE for locally advanced pancreatic cancer. Median follow-up was 23 months. Local failure or recurrence was seen in 17 patients at 3, 6, or 9 months post IRE. Change in tumor tissue resistance and the slope of the resistance curve were both significant in predicting LFR (p = 0.02 and p = 0.01, respectively). The median local disease-free survival was 5.5 months in patients who had recurrence compared with 12.6 months in patients who did not recur (p = 0.03). Neither mean change in tumor tissue resistance nor the slope of the resistance curve significantly predicted overall DFS. Conclusions Mean change in tumor tissue resistance and the slope of the resistance curve could be used intraoperatively to assess successful tumor ablation during IRE. Larger sample size and longer follow-up are needed to determine if these parameters can be used to predict DFS.
Maximal safe resection of gliomas near motor pathways is facilitated by intraoperative mapping. Here, the authors review their results with triple-modality asleep motor mapping with motor evoked ...potentials and bipolar and monopolar stimulation for cortical and subcortical mapping during glioma surgery in an expanded cohort.
This was a retrospective analysis of patients who underwent resection of a perirolandic glioma near motor pathways. Clinical and neuromonitoring data were extracted from the electronic medical records for review. All patients with new or worsened postoperative motor deficits were followed for at least 6 months. Regression analyses were performed to assess factors associated with a persistent motor deficit.
Between January 2018 and December 2021, 160 operations were performed in 151 patients with perirolandic glioma. Sixty-four patients (40%) had preoperative motor deficits, and the median extent of resection was 98%. Overall, patients in 38 cases (23.8%) had new or worse immediate postoperative deficits by discharge, and persistent deficits by 6 months were seen in 6 cases (3.8%), all in patients with high-grade gliomas. There were no new persistent deficits in low-grade glioma patients (0%). The risk factors for a persistent deficit included an insular tumor component (OR 8.6, p = 0.01), preoperative motor weakness (OR 8.1, p = 0.03), intraoperative motor evoked potential (MEP) changes (OR 36.5, p < 0.0001), and peri-resection cavity ischemia (OR 7.5, p = 0.04). Most persistent deficits were attributable to ischemic injury despite structural preservation of the descending motor tracts. For patients with persistent motor deficits, there were 3 cases (50%) in which a change in MEP was noted but subsequent subcortical monopolar stimulation still elicited a response in the corresponding muscle groups, suggesting axonal activation distal to a point of injury.
Asleep triple motor mapping results in a low rate of permanent deficits, especially for low-grade gliomas. Peri-resection cavity ischemia continues to be a significant risk factor for permanent deficit despite maintaining appropriate distance for subcortical tracts based on monopolar feedback.
Background
Few studies in the literature have reported recovery data for different types of recurrent laryngeal nerve injuries (RLNIs). This study is the first attempt to classify RLNIs and rank them ...by severity.
Methods
This prospective clinical study analyzed 281 RLNIs in which a true loss of signal was identified by intraoperative neuromonitoring (IONM), and vocal cord palsy (VCP) was confirmed by a postoperative laryngoscope. For each injury type, the prevalence of VCP, the time of VCP recovery, and physical changes on nerves were analyzed. Additionally, different RLNI types were experimentally induced in a porcine model to compare morphological change.
Results
The overall VCP rate in at-risk patients/nerves was 8.9/4.6 %, respectively. The distribution of RLNI types, in order of frequency, was traction (71 %), thermal (17 %), compression (4.2 %), clamping (3.4 %), ligature entrapment (1.6 %), suction (1.4 %), and nerve transection (1.4 %). Complete recovery from VCP was documented in 91 % of RLNIs. Recovery time was significantly faster in the traction group compared to the other groups (
p
< 0.001). The rates of temporary and permanent VCP were 98.6 and 1.4 % for traction lesion, 72 and 28 % for thermal injury, 100 and 0 % for compression injury, 50 and 50 % for clamping injury, 100 and 0 % for ligature entrapment, 100 and 0 % for suction injury, and 0 and 100 % for nerve transection, respectively. Physical changes were noted in 14 % of RLNIs in which 56 % of VCP was permanent. However, among the remaining 86 % IONM-detectable RLNIs without physical changes, only 1.2 % of VCP was permanent. A porcine model of traction lesion showed only distorted outer nerve structure, whereas the thermal lesion showed severe damage in the inner endoneurium.
Conclusions
Different RNLIs induce different morphological alterations and have different recovery outcomes. Permanent VCP is rare in lesions that are visually undetectable but detectable by IONM. By enabling early detection of RLNI and prediction of outcome, IONM can help clinicians plan intra- and postoperative treatment.
This study examined the diagnostic accuracy of significant changes of somatosensory evoked potentials (SSEPs) to evaluate and predict postoperative neurological deficits after posterior cervical ...fusions (PCF). Eight hundred forty six eligible patients underwent PCF at the University of Pittsburgh Medical Center (UPMC), from 2010 to 2012.
To assess the specificity and sensitivity of intraoperative monitoring in predicting postoperative neurological deficits during PCF.
We calculated the predictive value, including sensitivity and specificity, of changes in SSEPs to identify neurological deficits postoperatively. We used a receiver operating characteristic (ROC) curve with SSEP categories as cutoff values to further evaluate the diagnostic accuracy of change in SSEPs and postoperative neurological deficit.
All patients had preposition baselines and continuous SSEP monitoring throughout the surgery. Statistical analysis was completed using SPSS version 22 (IBM Corp., Armonk, NY).
Age and sex did not influence outcomes. Obesity affected patient outcome. The SSEP categories of significant changes and loss of responses resulted in a sensitivity/specificity of 0.30/0.96 and 0.16/0.98, respectively. The receiver operating characteristic curve has an area under the curve for significant change in/loss of SSEPs of 0.62/0.65 with a 95% confidence interval of 0.525 to 0.714/0.509 to 0.797.
Significant SSEP changes during PCF are a very specific but poorly sensitive indicator of postoperative neurological deficits. The odds ratio for significant changes in SSEPs and loss of waveforms was 9.80 and 11.82, respectively, with a 95% confidence interval of 4.695 to 20.46 and 4.45 to 31.41, respectively.
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