Continuous Intraoperative Monitoring Research Articles

Experience with the use of intraoperative continuous nerve monitoring in video-assisted neck surgery and external cervical incisions.

ObjectivesRecurrent laryngeal nerve (RLN) injury is one of the severe complications in thyroid surgery. Therefore, intraoperative nerve monitoring (IONM) has been widely used to identify the RLN and confirm its integrity. Recently, the usefulness of continuous IONM (CIONM) with automatic, periodic stimulation to the vagus nerve during thyroid surgery was reported. This study aimed to report our experience with minimally invasive video‐assisted endoscopic endocrine neck surgery (VANS), during which, CIONM was successfully applied for the first time.MethodsConsecutive patients who underwent thyroid surgery with CIONM, performed in our department using either external neck incision surgery or VANS between July 2017 and June 2019, were retrospectively analyzed.ResultsA total of 22 patients who underwent thyroid surgery with neck incision (14 cases; 7 men and 7 women; age, 21‐75 years [mean, 52 years]) or VANS (8 cases; 8 women, age, 20‐61 years [mean, 41 years]) were enrolled in this study. The addition of CIONM in VANS prolonged the operation's duration by approximately 30 minutes as the endoscopic surgery was technically more difficult. No intra‐ and postoperative incidence of transient or permanent RLN palsy was observed in any patient, except for three patients who underwent external neck incision surgery in whom combined resection was unavoidable due to tumor invasion of the RLN.ConclusionWe reported the first successful application of CIONM during thyroidectomy using VANS. Future clinical trials should clarify the benefits of CIONM when compared to intermittent IONM in VANS.Level of Evidence5.

Continuous Intraoperative Nerve Monitoring in Thyroidectomies: A Systematic Review and Meta-Analysis

Branchial clefts are most often associated with the pediatric population but can also affect adults. The adult population undergoing branchial cleft excision is poorly described. This study sought to describe the population and outcomes of those undergoing branchial cleft excision.

Techniques, Indications, and Outcomes in Magnetic Resonance-guided Focused Ultrasound Thalamotomy for Tremor.

Magnetic resonance (MR)-guided focused ultrasound surgery (MRgFUS) is the latest minimally invasive stereotactic procedure, and thalamotomy using this novel modality has demonstrated its effectiveness and safety, especially for patients with essential tremor (ET) and Parkinson’s disease (PD). In Japan, the application of MRgFUS to treat ET and PD has recently been covered by health insurance. Technically, the transducer with 1024 elements emits ultrasound beams, which are then focused on the target with a phase control, resulting in optimal ablation by thermal coagulation. The technical advantages of MRgFUS are continuous intraoperative monitoring of clinical symptoms and MR images and fine adjustment of the target by the steering function. Postoperative tremor control is compatible with other modalities, although long-term follow-up is necessary. The adverse effects are usually transient and acceptable. Prognostic factors for good tremor control include high temperature and large lesion size. A high skull density ratio is a factor to achieve high temperature and large lesioning, but it may not be necessary and sufficient for clinical outcomes. For patients with advanced symptoms such as bilateral tremor or head/neck tremor, deep brain stimulation may be recommended because of the adjustability of stimulation and the possibility of bilateral treatment. Patients have high expectations of MRgFUS because of its non-invasiveness. To perform this treatment safely and effectively, physicians need to understand the technological aspects, the physiological principles. To choose the appropriate modality, physicians also should recognize the clinical advantages and disadvantages of MRgFUS compared to other modalities.

Perioperative Considerations in Osteogenesis Imperfecta: A 20-Year Experience with the Use of Blood Pressure Cuffs, Arterial Lines, and Tourniquets.

Osteogenesis imperfecta (OI) is a rare genetic connective-tissue disorder with bone fragility. To avoid iatrogenic fractures, healthcare providers have traditionally avoided using non-invasive blood pressure (NIBP) cuffs and extremity tourniquets in the OI population in the perioperative setting. Here, we hypothesize that these procedures do not lead to iatrogenic fractures or other complications in patients with OI. A retrospective study of all children with OI who underwent surgery at a single tertiary care children’s hospital from 1998 to 2018 was performed. Patient positioning and the use of NIBP cuffs, arterial lines, and extremity tourniquets were documented. Fractures and other complications were recorded. Forty-nine patients with a median age of 7.9 years (range: 0.2–17.7) were identified. These patients underwent 273 procedures, of which 229 were orthopaedic operations. A total of 246 (90.1%) procedures included the use of an NIBP cuff, 61 (22.3%) an extremity tourniquet, and 40 (14.7%) an arterial line. Pediatric patients with OI did not experience any iatrogenic fractures related to hemodynamic monitoring or extremity tourniquet use during the 20-year period of this study. Given the benefits of continuous intra-operative hemodynamic monitoring and extremity tourniquets, we recommend that NIBP cuffs, arterial lines, and tourniquets be selectively considered for use in children with OI.

Incidence of peripheral nerve injury in revision total shoulder arthroplasty: an intraoperative nerve monitoring study

The incidence of nerve injuries in revision total shoulder arthroplasty (TSA) is not well defined in the literature and may be higher than that in primary procedures, with 1 study reporting a complication rate of 50% for shoulder revisions. Given that continuous intraoperative nerve monitoring (IONM) can be an effective tool in diagnosing evolving neurologic dysfunction and preventing postoperative injuries, the purpose of this study was to report on IONM data and nerve injury rates in a series of revision TSAs. A retrospective cohort review of consecutive patients who underwent revision TSA was performed from January 2016 to March 2020. Indications for revision included infection (n = 7); failed total arthroplasty and hemiarthroplasty secondary to pain, dysfunction, and/or loose components (n = 36); and periprosthetic fracture (n = 1). Of the shoulders, 32 underwent revision to a reverse TSA, 6 underwent revision to an anatomic TSA, and 6 underwent spacer placement. IONM data included transcranial electrical motor evoked potentials (MEPs), somatosensory evoked potentials, and free-run electromyography. The motor alert threshold was set at ≥80% signal attenuation in any peripheral nerve. Patients were screened for neurologic deficits immediately following surgery, prior to administration of an interscalene nerve block, and during the first 2 postoperative visits. Additional data collection included surgical indication, sex, laterality, age at surgery, procedure performed, body mass index, history of tobacco use, Charlson Comorbidity Index, medical history, and preoperative range of motion. A total of 44 shoulders in 38 patients were included, with a mean age of 63.2 years (standard deviation, 13.0 years). Of the procedures, 22.4% (n = 10) had an MEP alert, with 8 isolated to a single nerve (7 axillary and 1 radial) and 1 isolated to the axillary and musculocutaneous nerves. Only 1 patient experienced a major brachial plexus alert involving axillary, musculocutaneous, radial, ulnar, and median nerve MEP alerts, as well as ulnar and median nerve somatosensory evoked potential alerts. Age, sex, body mass index, Charlson Comorbidity Index, and preoperative range of motion were not found to be significantly different between cases in which an MEP alert occurred and cases with no MEP alerts. In the postoperative period, no minor or major nerve injuries were found whereas distal peripheral neuropathy developed in 4 patients (9.1%). Among 44 surgical procedures, no patients (0%) had a major or minor nerve injury postoperatively and 4 patients (9.1%) complained of distal peripheral neuropathy postoperatively. In this study, we have shown that through the use of IONM, the rate of minor and major nerve injuries can be minimized in revision shoulder arthroplasty.

Optical monitoring of cerebral perfusion and metabolism in adults during cardiac surgery with cardiopulmonary bypass.

During cardiac surgery with cardiopulmonary bypass (CPB), adequate maintenance of cerebral blood flow (CBF) is vital in preventing postoperative neurological injury - i.e. stroke, delirium, cognitive impairment. Reductions in CBF large enough to impact cerebral energy metabolism can lead to tissue damage and subsequent brain injury. Current methods for neuromonitoring during surgery are limited. This study presents the clinical translation of a hybrid optical neuromonitor for continuous intraoperative monitoring of cerebral perfusion and metabolism in ten patients undergoing non-emergent cardiac surgery with non-pulsatile CPB. The optical system combines broadband near-infrared spectroscopy (B-NIRS) to measure changes in the oxidation state of cytochrome c oxidase (oxCCO) - a direct marker of cellular energy metabolism - and diffuse correlation spectroscopy (DCS) to provide an index of cerebral blood flow (CBFi). As the heart was arrested and the CPB-pump started, increases in CBFi (88.5 ± 125.7%) and significant decreases in oxCCO (-0.5 ± 0.2 µM) were observed; no changes were noted during transitions off CPB. Fifteen hypoperfusion events, defined as large and sustained reductions in CPB-pump flow rate, were identified across all patients and resulted in significant decreases in perfusion and metabolism when mean arterial pressure dropped to 30 mmHg or below. The maximum reduction in cerebral blood flow preceded the corresponding metabolic reduction by 18.2 ± 15.0 s. Optical neuromonitoring provides a safe and non-invasive approach for assessing intraoperative perfusion and metabolism and has potential in guiding patient management to prevent adverse clinical outcomes.

内視鏡下甲状腺手術（VANS法）における術中持続神経モニタリングの経験

内視鏡下甲状腺手術（VANS法）における術中持続神経モニタリングの経験

Safety of Ligasure exact dissector in thyroidectomy with continuous neuromonitoring: a porcine model.

The purpose of this study was to investigate and define safety parameters for using the Ligasure exact dissector (LED) for dissection close to the recurrent laryngeal nerve (RLN) during thyroidectomy. Real-time electrophysiologic electromyographic (EMG) tracings were recorded in 16 RLNs (8 piglets) during various applications of LED under continuous intraoperative monitoring in this prospective porcine model study. In the activation study, LED was activated at varying distances from the RLN. In the cooling study, LED was activated with different cooling times or after touching the sternocleidomastoid muscle before application to the RLN. In the activation study, no adverse EMG events occurred at distances longer than 1 mm. In the cooling study, no adverse EMG events occurred after a 2-second cooling time. Additionally, no adverse EMG events occurred when a sternocleidomastoid muscle touch maneuver was used for cooling. The LED can be safely used at distance of 1 mm or longer, and it should be cooled for at least 2 seconds or by muscle touch maneuver. Thyroid surgeons can avoid RLN injury if standard procedures for LED use are observed.

Clinical Experience with the Continuous Intraoperative Nerve Monitoring System in Mediastinoscopic Esophagectomy

Clinical Experience with the Continuous Intraoperative Nerve Monitoring System in Mediastinoscopic Esophagectomy

The Yield of Intraoperative Fetal Monitoring During Nonobstetric Surgery [34K

INTRODUCTION: While ACOG supports indicated surgery for pregnant patients, there is no clear consensus on optimal fetal monitoring for such cases. We examined whether continuous intraoperative electronic fetal monitoring (ciEFM) for nonobstetric surgeries after viability impacts decision for obstetric intervention and subsequent perinatal outcomes. METHODS: IRB approval was obtained for this retrospective cohort study conducted at a single academic center between January 2013 and March 2019. Demographic and outcome data were compared between ciEFM vs pre/post-procedure EFM. Multiple logistic regression was applied to adjust for clinical covariates. RESULTS: Of 1,060 cases reviewed, 43 (4.1%) were performed after viability (gestational age (GA) range: 23.7 to 36.4 weeks). ciEFM was used in 24 cases (56%). Two cases required intraoperative resuscitation in the ciEFM group, one with fluid bolus and one with emergent delivery (P=.49). ciEFM cases lasted longer (105 vs 40 minutes, P<.01) and were more likely to be performed under general anesthesia (83.3% vs 26.3%, P<.01). ciEFM had no association with non-reassuring postoperative EFM (18.2% vs 15.4%, P=1.00), postoperative tocolytic use (29.2% vs 10.5%, P=.26), or GA at delivery (37.1 vs 37.2, P=.92). There was no association on the rate of preterm delivery when adjusted for type, or length of surgery, and type of anesthesia (aOR 1.82, 95% CI 0.20-16.4, P=.59). CONCLUSION: ciEFM does not significantly affect intraoperative or postoperative obstetrical outcomes. This data can help obstetric providers allocate limited resources, reassure other surgical providers, and appropriately counsel patients who are about to undergo nonobstetric surgery.

Continuous Neural Monitoring in Endoscopic Thyroidectomy: Feasibility Experimental Study for Transcutaneous Vagal Nerve Stimulation.

Background: Adoption of continuous intraoperative neural monitoring (C-IONM) in endoscopic thyroid surgery is limited due to the uneasy application of C-IONM electrode. Feasibility for transcutaneous vagal nerve stimulation was tested. Materials and Methods: Vagus nerve (VN) and recurrent laryngeal nerve (RLN) were mapped and stimulated in different neck sites by (1) transcutaneous monopolar intermitted stimulation; (2) prototype for continuous transcutaneous stimulating electrodes (TSEs), that is, suction ball C-IONM electrode remodeled; (3) stimulation subsequently to neck CO2 insufflation; (4) direct stimulation of surgical exposed nerves. Electromyographic (EMG) parameters were compared. Results: Six anterior neck locations evoked EMG signals of VNs and RLNs. Location Nos. 3 and 6 according to our scheme were over the VNs, confirmed by ultrasonography and subsequent dissection. Other locations did not correspond to nerves sites. Transcutaneous thresholds were higher than surgical exposed ones to produce a consistent and satisfactory EMG response. TSE recorded solely in location No. 5 with amplitude values 256-9 μV. It was not possible to stimulate and monitor the RLN and VN after neck CO2 insufflation. Conclusion: Transcutaneous C-IONM is unfeasible for endoscopic thyroidectomy.

Pre-Prototype Stimulating and Recording Endotracheal Tube for Continuous Monitoring of the Recurrent Laryngeal Nerve During Thyroid Surgery

Introduction Continuous intraoperative neural monitoring (C-IONM) is a promising technology used to decrease recurrent laryngeal nerve (RLN) damage during thyroid surgery. However, C-IONM use is limited due to its challenging application. C-IONM requires dissection of the carotid sheath and placement of an electrode around the vagus nerve (VN). In our study, we simultaneously stimulated and monitored the proximal RLN trans-tracheally using surface electrodes that were positioned solely on the endotracheal tube. Methods We described the design, implementation, and testing of a pre-prototype, combined stimulating and recording endotracheal tube (SRET) that continually delivered current from tube edge, and tested the function of the RLN at the vocal cords (VC). The SRET was tested in vivo on 10 RLNs using 5 pigs as animal models. Results The SRET was capable of the following, delivery of continuous trans-tracheal stimulation to the proximal RLN, continuous trans-tracheal stimulation-induced VC movement, and standard ipsilateral RLN biphasic waveforms with latency and amplitude; and recording evoked responses were recorded in the ipsilateral RLN. Conclusion The pre-prototype SRET represents a possible advancement in technology because it simplified the C-IONM. Thus, the SRET provides a minimally invasive, alternative application to the C-IONM vagal nerve cuff electrodes.

Intra-operative vagal neuromonitoring predicts non-recurrent laryngeal nerves: technical notes and review of the recent literature

Background During thyroid surgery, extreme caution must be taken not to harm the recurrent laryngeal nerve to avoid vocal cord palsy. A non-recurrent laryngeal nerve (NRLN) is a rare anatomical variation that is extremely vulnerable during thyroid surgery. Methods Description of two NRLN during thyroid surgery discovered early by using continuous intra-operative vagal nerve neuromonitoring and review of the literature. Results During thyroid surgery, we use continuous intra-operative vagal nerve neuromonitoring starting with checking vagal nerve signals. It is essential to start stimulation in the most proximal portion of the carotid sheath. An absent pre-dissection signal on the right vagal nerve with a positive signal on the left vagal nerve indicates a non-recurrent course of the right laryngeal nerve. Post-operatively computed tomography scan (CT-scan) was performed and showed an associated extra-anatomical course of the subclavian artery also known as an arteria lusoria. Conclusion The NRLN is an important surgical challenge because unilateral palsy can lead to permanent hoarseness. This anomaly emphasizes the importance of a thorough surgical dissection and the use of intra-operative vagal nerve neuromonitoring. Our method of continuous intra-operative vagal nerve monitoring makes it possible to predict a non-recurrent laryngeal nerve in an early stage during surgery.

Continuous intraoperative nerve monitoring

Continuous intraoperative nerve monitoring

Multicenter comparison of three intraoperative hemoglobin trend monitoring methods

Transfusion decisions are guided by clinical factors and measured hemoglobin (Hb). Time required for blood sampling and analysis may cause Hb measurement to lag clinical conditions, thus continuous intraoperative Hb trend monitoring may provide useful information. This multicenter study was designed to compare three methods of determining intraoperative Hb changes (trend accuracy) to laboratory determined Hb changes. Adult surgical patients with planned arterial catheterization were studied. With each blood gas analysis performed, pulse cooximetry hemoglobin (SpHb) was recorded, and arterial blood Hb was measured by hematology (tHb), arterial blood gas cooximetry (ABGHb), and point of care (aHQHb) analyzers. Hb change was calculated and trend accuracy assessed by modified Bland–Altman analysis. Secondary measures included Hb measurement change direction agreement. Trend accuracy mean bias (95% limits of agreement; g/dl) for SpHb was 0.10 (− 1.14 to 1.35); for ABGHb was − 0.02 (− 1.06 to 1.02); and for aHQHb was 0.003 (− 0.95 to 0.95). Changes more than ± 0.5 g/dl agreed with tHb changes more than ± 0.25 g/dl in 94.2% (88.9–97.0%) SpHb changes, 98.9% (96.1–99.7%) ABGHb changes and 99.0% (96.4–99.7%) aHQHb changes. Sequential changes in SpHb, ABGHb and aHQHb exceeding ± 0.5 g/dl have similar agreement to the direction but not necessarily the magnitude of sequential tHb change. While Hb blood tests should continue to be used to inform transfusion decisions, intraoperative continuous noninvasive SpHb decreases more than − 0.5 g/dl could be a good indicator of the need to measure tHb.

Continuous Noninvasive Haemoglobin Monitoring in Vascular Surgery within the Goal-Directed Therapy Protocol

The optimisation of DO2, within the Goal-Direct Therapy Protocol (GDTP) in high-risk surgical patients, improves their outcome. Haemodynamic and haemoglobin monitoring become crucial to achieve optimal DO2. Our study compared Hb as measured by three methods: Coulter Counter (standard laboratory method) and CO-Oximetry (Masimo rainbow SET Radical 7 Pulse CO-Oximetry (SpHb) and Blood Gas Analysis) to establish the utility of the Hb continuous intraoperative monitoring, within the GDTP, in high-risk bleeding surgery. We studied 72 patients undergoing open abdominal aortic aneurysm repair. We compared the accuracy and the trending ability in measuring the haemoglobin concentration between the three methods (Coulter Counter, BGA and Masimo). We collected three simultaneous haemoglobin measurements: after induction of anaesthesia, pre- and post-aortic cross-clamping and at the end of the surgery. SpHb showed an excellent r-value for all samples (0.952, CI-95% (0.939, 0.961), p-value < 0.0001) compared to laboratory measurements. The results of the linear regression between SpHb and laboratory, for each time considered, demonstrated that SpHb showed excellent r and R2 value. All data were statistically significant, with a p-value <0.0001. A Bland-Altmann analysis for SpHb vs. laboratory showed a bias of −1.45 g/dL (CI-95% −1.51 and −1.39 g/dL, LOA from −2.42 to −0.48 g/dL) with a precision of 0.49 g/dL. Four-quadrant plot trend analyses showed a high concordance rate ≥90%. During elective high-risk surgery, Masimo Pulse CO-Oximetry is not enough sufficiently accurate to assess the current value of haemoglobin but may be useful for the trend value ensuring DO2 within intraoperative GDTP.

The influence of decompressive craniectomy on intracranial pressure in patients with severe traumatic brain injury

A prospective study of decompressive craniectomy (DC) influence on intracranial pressure (ICP) in patients with severe traumatic brain injury (TBI) has been performed using intraoperative and postoperative monitoring. Purpose. To study quantitative indicators of DC influence on ICP in patients with severe TBI through continuous intraoperative and postoperative monitoring. Materials and methods. A total of 75 patients (14 women and 61 men) with severe TBI (the GCS score at admission was 8 or less) who underwent DC and dura mater opening with further duraplasty were included in the study. A unilateral wide fronto-temporo-parietal decompression was performed. Primary DC was performed in 64 patients. Secondary DC was performed in 11 patients. ICP measurements were carried out using parenchymal sensors on the REF HDM 26.1/FV500 Brain Pressure Monitor (Spiegelberg,Hamburg,Germany). ICP sensor was installed during the first surgery stage. In each case, a decompressive effect of each surgery stage and the entire surgery was assessed. Results. High ICP was diagnosed in 86.7 % of patients preoperatively and in 24 % of patients (P < 0.05) postoperatively. The mean post-DC ICP decreased from 39 mmHg (preoperative) to 15.8 mmHg (postoperative), the average decrease was 59.5 % from the baseline. The largest decrease in ICP by 42.6 % was detected after bone flap removal. Dura mater opening resulted to additional decrease in ICP by 24.7 %. Conclusions. A unilateral wide fronto-temporo-parietal craniectomy is an effective method for sustainable ICP reduction. DC reduces the percentage of patients with intracranial hypertension. Decompressive effect of a surgery does not significantly depend on DC, brain injury type or traumatic compression substrate.

Efficacy of continuous neuromonitoring in thyroid surgery: preliminary report of a single-center experience.

The continuous intraoperative nerve monitoring (CIONM) technique seems to be acknowledged as a useful tool to prevent impending nerve injury, because it constantly provides valuable real-time information. Aim of the study is to evaluate the impact of the CIONM technique on functional outcome i.e., recurrent laryngeal nerve (RLN) palsy, compared to the traditional surgical procedure. From January to December 2016, 197 patients who underwent thyroid surgery were included in this retrospective study: 94 patients had CIONM procedure and 103 traditional technique, according to the order of the operating room list. A total of 8 patients showed a damage to left or right vocal cord: 3 patients after CIONM procedure, and 5 patients after traditional surgical procedure. After matching for propensity score, 188 patients were eventually considered and 7 RLN palsy were identified: 3 in CIONM and 4 in traditional surgical procedure. The analysis performed on the matched propensity score sample showed a non-significant difference between the two procedures. In our experience no significant differences in functional outcomes were found between the use of CIONM and the standard technique.

Cost and training are diffusion patterns limits for neural monitoring in thyroid surgery.

The use of intermitted (I-IONM) and continuous intraoperative neural monitoring (C-IONM) in thyroid surgery is increasing, but true characterisation of the diffusion of I-IONM and especially C-IONM is not available (1-5).

Preoperative electrophysiological analysis predicts preservation of hearing and facial nerve function following vestibular schwannoma surgery with continuous intraoperative neural monitoring: Clinical outcomes of 22 cases.

Preoperative electrophysiological analysis predicts preservation of hearing and facial nerve function following vestibular schwannoma surgery with continuous intraoperative neural monitoring: Clinical outcomes of 22 cases.