Intraoperative Monitoring Research Articles

Outcomes of a modified technique of partial parotidectomy and novel parotid tumour position classification from a single surgeon prospective database.

Conservative parotidectomy for benign tumours reduces facial nerve palsy, without increasing local recurrence. We report a modified technique of partial parotidectomy and using a novel description of tumour position, explore relationships between tumour position and histological margins, facial nerve palsy and local recurrence. A prospectively collected single surgeon parotidectomy database was analysed, including tumour location (superficial/deep lobe; central/peripheral) and outcomes. A partial parotidectomy identified the facial nerve and the proximal portion of its branches with a macroscopically clear resection margin. Mean follow up was 5.9 years for pleomorphic adenomas. Three hundred and three patients underwent parotidectomy; 257 (84.8%) were superficial and 46 (15.2%) deep lobe. Tumour position was recorded in 291: 236 (81.1%) were peripheral tumours and 55 (18.9%) central. Histological margin involvement was similar in central and peripheral tumours, both overall and for superficial and deep lobe tumours, but was commoner in central deep lobe tumours, (P = 0.003). Temporary partial facial nerve palsy occurred in 21 (6.9%), with one permanent partial nerve palsy (0.3%). Deep lobe tumours and total parotidectomy were associated with facial nerve palsy (P = 0.01). Facial nerve monitoring reduced the risk of palsy (P < 0.01). Local recurrence of pleomorphic adenomas was uncommon, occurring in 3 (2.0%) of 151 patients. This series confirms the safety and adequacy of more conservative partial parotidectomy for benign tumours, highlighting most tumours are peripheral, but not more prone to histological margin involvement or local recurrence, and with routine intraoperative facial nerve monitoring, is achieved with low facial nerve palsy rates.

Intravenous lidocaine infusion therapy and intraoperative neurophysiological monitoring in adolescents undergoing idiopathic scoliosis correction: A retrospective study.

Posterior spinal instrumentation and fusion is an established surgical procedure for the correction of adolescent idiopathic scoliosis. Intraoperative neurophysiological monitoring is standard practice for this procedure. Anesthetic agents can have different, but significant, effects on neurophysiological monitoring outcomes. To determine if intravenous lidocaine infusion therapy has an impact on the intraoperative neurophysiological monitoring during posterior spinal instrumentation and fusion for adolescent idiopathic scoliosis. Following ethical approval, we conducted a retrospective review of charts and the archived intraoperative neurophysiological data of adolescents undergoing posterior spinal instrumentation and fusion for adolescent idiopathic scoliosis. Intraoperative neurophysiological monitoring data included the amplitude of motor evoked potentials and the amplitude and latency of somatosensory evoked potentials. A cohort who received intraoperative lidocaine infusion were compared to those who did not. Eighty-one patients were included in this analysis, who had surgery between February 4, 2016 and April 22, 2021: 39 had intraoperative intravenous lidocaine infusion and 42 did not. Based on hourly snapshot data, there was no evidence that lidocaine infusion had a detrimental effect on the measured change from baseline for MEP amplitudes in either lower (mean difference 41.9; 95% confidence interval -304.5 to 388.3; p = .182) or upper limbs (MD -279.0; 95% CI -562.5 to 4.4; p = .054). There was also no evidence of any effect on the measured change from baseline for SSEP amplitudes in either lower (MD 16.4; 95% CI -17.7 to 50.5; p = .345) or upper limbs (MD -2.4; 95% CI -14.5 to 9.8; p = .701). Finally, there was no evidence of a difference in time to first reportable neurophysiological event (hazard ratio 1.13; 95% CI 0.61 to 2.09; p = .680). Data from these two cohorts provide preliminary evidence that intravenous lidocaine infusion has no negative impact on intraoperative neurophysiological monitoring during PSIF for adolescent idiopathic scoliosis.

12313 Parathyroid Carcinoma Presenting As Right Foot Pain And Swelling In A Young Male - A Case Report

Abstract Disclosure: F.E. Sorsona: None. L. Lopez: None. Parathyroid carcinoma is a rare cause of hyperparathyroidism that is challenging to diagnose. We report a case of parathyroid carcinoma with an unusual initial presentation of right foot pain and swelling in a young 26-year-old Filipino male. Physical examination revealed a palpable 1 x 1 cm mass with tenderness on his right foot. Initial work-up showed a persistently elevated serum ionized calcium (range: 1.7 - 2.19 mmol/L) with markedly high intact parathyroid hormone (1,890 pg/ml). A right foot x-ray revealed a lytic bone lesion on the 3rd metatarsal. Skeletal survey revealed diffuse lytic bone lesions. Comprehensive neck ultrasound showed a 4 x 1.6 x 2.5 cm complex nodule adjacent to the inferior pole of the left lobe of the thyroid gland with intralesional calcifications. A 4D CT scan showed a 3.3 x 2.2 x 2 cm hypervascular nodule inferior to the left thyroid lobe with early contrast washout, likely parathyroid in origin, and a possible brown tumor in the right fourth rib. Patient underwent parathyroidectomy with intraoperative PTH monitoring showing a marked reduction of intact PTH by 87% (235.9 pg/ml from 1,890 pg/ml), accompanied by reduction of serum ionized calcium. The histopathology reported parathyroid carcinoma highlighted by lymphovascular invasion, atypical round cells in sheets and nests, with enlarged, mildly pleomorphic, hyperchromatic nuclei and prominent nucleoli. Two months after surgery, normal serum ionized calcium was maintained with calcium supplementation with reported relief of right foot pain and swelling. The patient continues to follow up regularly for monitoring of treatment response. Presentation: 6/2/2024

Influence of Preoperative Motor Score and Patient Comorbidities on Transcranial Motor-Evoked Potential Acquisition in Intracranial Surgery: A Retrospective Cohort Study.

Intraoperative neurophysiological monitoring plays a pivotal role in modern neurosurgery, aiding in real-time assessment of eloquent neural structures to mitigate iatrogenic neural injury. This study represents the largest retrospective series to date in monitoring corticospinal tract integrity during intracranial surgery with transcranial motor-evoked potentials (TCMEPs), focusing on the influence of demographic factors, comorbidities, and preoperative motor deficits on the reliability of intraoperative neurophysiological monitoring. While the impact of patient-specific factors affecting TCMEP monitoring in spine surgery is well-documented, similar insights for intracranial surgery are lacking. A total of 420 craniotomy patients were retrospectively analyzed from electronic medical records from December 2017 to February 2023, excluding patients without preoperative Medical Research Council scores or medical histories. Using intrinsic hand muscles as a robust data set, 840 hand TCMEPs acquired during intracranial surgery were assessed. Demographic and clinical factors, including preoperative motor scores, were analyzed to identify associations with TCMEP acquisition and amplitude. Nonparametric statistics and multivariate regression analysis were employed. TCMEPs were successfully acquired in 734 (87.7%) patient hands, even in the presence of preoperative motor deficits in 13.9% of total patient hands. Preoperative motor scores did not predict the ability to acquire baseline TCMEPs ( P = .6). Notably, older age ( P < .001) and hypertension ( P = .01) were independent predictors of lower TCMEP acquisition rates. Preoperative motor scores significantly influenced TCMEP amplitudes, with higher scores correlating with higher amplitudes (1771 [SD = 1550] eve vs 882 [SD = 856] μV, P < .0001). Older age ( P < .001) and chronic kidney disease ( P = .04) were also associated with reduced TCMEP amplitudes. Our investigation into TCMEPs during intracranial surgery demonstrated a notably high acquisition rate in hand muscles, irrespective of preoperative motor deficits. Preoperative motor scores reliably correlated with TCMEP amplitudes in a linear fashion while advanced age and renal disease emerged as independent predictors of lower TCMEP amplitudes.

Delayed-onset vocal cord palsy after thyroidectomy occurring despite normal initial post-operative endoscopy.

Recurrent laryngeal nerve (RLN) injury is a known complication of thyroidectomy. Most cases manifest immediately and are promptly recognized. Rarely, some patients experience delayed-onset vocal cord palsy. This can occur despite normal findings on intra-operative nerve monitoring and initial post-operative endoscopy. This can cause considerable distress for patients, and its incidence and prognosis should be recognized. We report seven patients experiencing delayed-onset RLN palsy (RLNP) after thyroidectomy. All had normal findings on pre-operative flexible nasoendoscopy (FNE), intra-operative nerve monitoring at conclusion of surgery, and initial post-operative FNE. All diagnoses of RLNP were confirmed on endoscopy. Serial FNE examinations were performed to evaluate recovery. Of seven patients (43% male, median age 65 years), the median timing of delayed-onset RLNP was 12 (range 9-35) days. RLNP was diagnosed on the unilateral side of surgery in six out of seven patients (86%). All received conservative management, including referral to voice therapy. All seven patients recovered vocal cord function after a median duration of 24 weeks (range 8-52 weeks), and six within ~6 months (28 weeks). The incidence of this complication was 0.1% (among 6607 thyroidectomies). We report the first Australian series of delayed-onset vocal cord palsy after thyroidectomy. We explore its prognosis, discussing different pathophysiological mechanisms and the timeframe for recovery compared to most other RLN injuries. This may assist recognition of a rare complication, reassure patients, and facilitate early intervention to improve a patient's quality of life.

Variable practice patterns in the surgical management of renal hyperparathyroidism

BackgroundHyperparathyroidism is common among patients with chronic kidney disease, end-stage kidney disease, and kidney transplant. The American Association for Endocrine Surgery published clinical practice guidelines that address the surgical treatment of secondary and tertiary hyperparathyroidism. The purpose of this study is to determine practice patterns for the surgical management of secondary and tertiary hyperparathyroidism prior to guideline publication. MethodsWith the approval of the American Association for Endocrine Surgery, a Qualtrics email survey was sent to the Association’s membership in 2022 about current clinical decision making for surgical treatment of secondary and tertiary hyperparathyroidism. Respondents were divided into groups based on surgical subspecialty (endocrine surgery versus non-endocrine surgery), yearly parathyroidectomy volume, and yearly parathyroidectomy volume for surgical treatment of secondary and tertiary hyperparathyroidism. Descriptive statistics were performed; the role of volume was evaluated. ResultsThere were 142 responses from 795 solicited email addresses (18% response rate); 114 (84%) identified as endocrine surgeons. The majority (62%) perform >50 parathyroidectomies yearly, but most perform <10 parathyroidectomies for surgical treatment of secondary and tertiary hyperparathyroidism per year (<10/y, 53.7%; 10–30/y, 41.9%; >30/y, 4.4%). Subtotal parathyroidectomy is most commonly performed for surgical treatment of secondary (83%) and tertiary (52%) hyperparathyroidism, but transcervical thymectomy variably performed for both. There was no consensus regarding starting calcitriol preoperatively (always 43%, never 25%, depends on vitamin D levels 24%) or stopping cinacalcet (2 weeks prior 28%, day of surgery 29%, postoperatively 20%). Surgeons who perform >10 parathyroidectomies per year for surgical treatment of secondary and tertiary hyperparathyroidism were less likely to consider the patient's preoperative vitamin D levels to inform their decision to start calcitriol before surgery (<10 cases/year, 34%; ≥10 cases/year 15%; P = .023), were more likely to have a postoperative hypocalcemia protocol managed by the surgical team (<10 cases/year, 49%; ≥10 cases/year, 58%; P = .029), and were more likely to use intraoperative parathyroid hormone monitoring for tertiary hyperparathyroidism (<10 cases/year, 70%; ≥10 cases/year, 87%; P = .046). ConclusionThe majority of respondents perform <10 parathyroidectomies yearly for surgical treatment of secondary and tertiary hyperparathyroidism. Subtotal parathyroidectomy was most commonly performed, but there was little other consensus regarding preoperative management, intraoperative decision-making, and postoperative care. Opportunity exists through guideline dissemination to improve heterogeneity of care provided to surgical treatment of secondary and tertiary hyperparathyroidism patients.

143 - Exploration of the relationship between the results of Urethral pressure profilometry and the efficacy and complications of artificial urethral sphincter implantation: based on real-time intraoperative monitoring

143 - Exploration of the relationship between the results of Urethral pressure profilometry and the efficacy and complications of artificial urethral sphincter implantation: based on real-time intraoperative monitoring

Current trends in vestibular schwannoma management at a referral center in Indonesia: A cross-sectional study with retrospective data collection

Background. Vestibular schwannoma (VS) is the most common benign brain tumor of the cerebellopontine angle. Due to its location, this pathology can create both focal and general deficits. The registry system for VS in Indonesia is developing, including in the author’s institution, which eventually shows a changing trend in managing VS. Methods. We retrospectively collected data from all patients diagnosed with vestibular schwannoma, based on histological or radiological results. Treatments included craniotomy and/or Gamma Knife Radiosurgery (GKRS) from 2018 to 2023. Results. Data from 88 patients were analyzed. The number of treated patients has increased annually. VS predominantly affects females (64%). The proportion between GKRS and craniotomy procedures also shifted throughout the year. Common symptoms included hearing loss (63.6%), disequilibrium (50%), and headaches (39.7%). The most common tumor size was medium (15-30 mm; n=37; 42%). Tumors that fell into the intrameatal and small (&lt;15 mm) categories were all treated with GKRS, whereas the other groups were divided into GKRS and craniotomy. GKRS demonstrated high efficacy in tumor control and favorable hearing and facial nerve preservation, whereas craniotomy remained crucial for larger tumors. Conclusion. The number of VS diagnosed each year has increased in our center, accompanied by a noticeable shift in preference from GKRS to craniotomy, which is influenced by the integration of intraoperative monitoring. Treatment preference was further determined based on the clinical profile and tumor size. In the future, there is a need to develop a national registry to better reflect the true incidence of VS within the Indonesian population.

Surgical Treatment of Spinal Intra-Extradural Meningioma: A Clinical Case

Spinal meningiomas are rare, predominantly benign tumors that exhibit slow growth and typically have a non-invasive pattern of development. They originate from arachnoid cells and fibroblasts of the dura mater. Despite their benign nature, some meningiomas can exhibit intra-extradural extension, complicating both diagnosis and treatment. This article presents a clinical case involving a patient with an intra-extradural spinal meningioma. Despite radiological imaging suggesting a neurinoma, the final diagnosis confirmed a meningioma. Case Report: A female patient underwent surgical tumor resection through a posterolateral approach with laminectomy and facetectomy at the C4-C5 vertebral levels. The tumor, extending through the intervertebral foramen, was completely resected along with the affected nerve root. Histological examination verified a Grade II meningioma. Discussion: Despite advancements in neuroimaging and surgical techniques, intraoperative findings can be unpredictable, necessitating an adaptive approach to tumor resection. The article emphasizes the importance of adequate preoperative planning and the use of intraoperative neurophysiological monitoring to reduce the risk of complications and improve treatment outcomes. Conclusions: The primary treatment for spinal meningiomas is surgical. For dorsal and lateral localizations, total resection with the involved dura mater (Simpson Grade I) is optimal. For ventral localizations, tumor resection with coagulation of the dural attachment site (Simpson Grade II) is preferred. Preoperative and intraoperative use of electrophysiological methods is recommended to assess the functional status of neural structures. Intra-extradural localization of meningiomas is rare and presents significant challenges in preoperative diagnosis, requiring specific skills for effective removal.

Learnable real-time inference of molecular composition from diffuse spectroscopy of brain tissue.

Diffuse optical modalities such as broadband near-infrared spectroscopy (bNIRS) and hyperspectral imaging (HSI) represent a promising alternative for low-cost, non-invasive, and fast monitoring of living tissue. Particularly, the possibility of extracting the molecular composition of the tissue from the optical spectra deems the spectroscopy techniques as a unique diagnostic tool. No established method exists to streamline the inference of the biochemical composition from the optical spectrum for real-time applications such as surgical monitoring. We analyze a machine learning technique for inference of changes in the molecular composition of brain tissue. We propose modifications to the existing learnable methodology based on the Beer-Lambert law. We evaluate the method's applicability to linear and nonlinear formulations of this physical law. The approach is tested on data obtained from the bNIRS- and HSI-based monitoring of brain tissue. The results demonstrate that the proposed method enables real-time molecular composition inference while maintaining the accuracy of traditional methods. Preliminary findings show that Beer-Lambert law-based spectral unmixing allows contrasting brain anatomy semantics such as the vessel tree and tumor area. We present a data-driven technique for inferring molecular composition change from diffuse spectroscopy of brain tissue, potentially enabling intra-operative monitoring.

Facial Nerve Injury after Extracapsular Dissection for Benign Parotid Tumors with and without Intraoperative Monitoring: A Retrospective Study of a Single Center.

Facial nerve injury (FNI) is the most common complication of parotid surgery and manifests as FN paralysis. The use of intraoperative facial nerve monitoring (IFNM) is becoming an established intraoperative aid for surgeons, assisting in the identification of the location and dissection of the facial nerve trunk or branches. The postoperative outcomes of parotid surgery with and without monitoring have been addressed in only a limited number of studies. The objective of this study is to evaluate the incidence of postoperative paralysis in patients undergoing extracapsular dissection (ED) for benign parotid tumors concerning the use or non-use of IFNM. The retrospective study was conducted at the Maxillo-Facial Department of the Magna Graecia University of Catanzaro. The patients were divided into two groups: Group 1 consisted of patients who underwent surgery without IFNM (1 January 2015 to 31 December 2018); Group 2, on the other hand, consisted of patients who underwent surgery with IFNM (1 January 2019 to 31 December 2022). Group 2 employed the Nerve Integrity Monitor (Medtronic's NIM®). To classify the FN function, we employed the modified House-Brackmann classification system. To evaluate the dependence between the "use of IFNM" and "postoperative paralysis", a descriptive analysis was conducted, including applying the Chi-squared test and calculating the Pearson correlation. Subsequently, a binary logistic regression model was applied to further evaluate the correlation between the latter. The level of statistical significance was set at p < 0.05. A total of 276 patients were included in the study: 120 subjects were assigned to Group 1 (43.5%, comprising 60 men and 60 women) and 156 subjects were assigned to Group 2 (56.5%, comprising 93 men and 63 women). In 91.7% of the cases (n. 253, precisely 105 in Group 1 and 148 in Group 2), no FNI occurred. In 8.33% of the cases (n. 23, specifically 15 in Group 1 and 8 in Group 2), postoperative paralysis was observed. Of these subjects, only two in Group 1 had permanent paralysis (8.69%); therefore, 91.31% had transient paralysis. As a result, 91.31% of the subjects exhibited transient paralysis. In the case of FNI, 78% of the cases involved the marginal mandibular branch (n. 18), 13% involved the temporo-zygomatic branch (n. 3), and 7% involved more than one branch (n = 2). The results of the multivariable binary logistic regression analysis demonstrated that the use of IFNM was a statistically significant influencing factor, with an estimated reduction in postoperative paralysis of approximately 62% (OR 0.378; 95% CI: 0.155-0.92). In Group 2, the occurrence of transient complications was significantly reduced (OR 0.387; 95% CI: 0.149-1.002 with p < 0.05). The use of IFNM in the ED for benign parotid tumors significantly reduces the rate of FNI and, consequently, postoperative FN paralysis. On the other hand, the use of monitoring systems must not replace the experience and anatomical knowledge of the surgeon.

Changes in Neonatal Intraoperative Electroencephalogram Alpha: Delta Ratios Precede Neurologic Injury.

Background: Unrecognized intraoperative cerebral ischemia during neonatal aortic arch reconstruction may precede neurologic injury. Electroencephalogram (EEG) alpha:delta ratio (A:D) changes predict cerebral ischemia; however, if A:D differences can identify ischemia during neonatal antegrade cerebral perfusion (ACP) and aortic arch reconstruction is unknown. We hypothesized that A:D changes would precede neurologic injury. Methods: Simultaneous EEG derived left versus right: hemispheric and anterior cerebral A:Ds were retrospectively measured at baseline and every 5 min during arterial cannulation, cooling, ACP, and the rewarming phases of the operation. A paired left versus right A:D difference >25% was considered significant for ischemia, and the duration of a significant and continuous A:D difference was quantified in minutes. Neonates were divided into two groups: (1) new neurologic injury (stroke or seizure) and (2) no known neurologic injury. Results: From 72 neonates, there were no significant differences in the baseline A:Ds. Seven neonates (9.7%) developed a new neurologic injury (seizure = 3, stroke = 2, seizure and stroke = 2). Male gender and longer ACP times were significantly associated with neurologic injury. In neonates with a neurologic injury, the duration of a significant and continuous A:D difference was longer within the hemispheric and anterior regions. Multivariable analysis demonstrated that a significant and continuous anterior A:D difference (odds ratio: 1.345, 95% CI 1.058-1.712; P = .01) was independently associated with neurologic injury. Conclusions: A longer continuous anterior A:D difference > 25% was independently associated with neurologic injury. Intraoperative EEG monitoring could be considered during neonatal arch reconstruction.

Reduction of the acquisition time needed to obtain somatosensory evoked potentials by estimation of the required averaging sweep count by an algorithm.

Somatosensory evoked potentials are frequently acquired by stimulation of the median or tibial nerves (mSEPs and tSEPs) for intraoperative monitoring of sensory pathways. Due to their low amplitudes it is common practice to average 200 or more sweeps to discern the evoked potentials from the background EEG. The aim of this study was to investigate if an algorithm designed to determine the lowest sweep count needed to obtain reproducible evoked potentials in each patient significantly reduces the median necessary sweep count to under 200. 30 patients undergoing spinal surgery at the Department of Neurosurgery were included in the study. Beginning with a sweep count of 200 an algorithm was designed to determine the lowest sweep count that yielded reproducible evoked potentials in each patient. By this algorithm the minimal sweep count was determined in 15 patients for mSEPs and in 15 patients for tSEPs. The required sweep count was below 200 in 14 of 15 patients for mSEPs (93.3%) with a mean sweep count of 56 ± 51. For tSEPs the sweep count was below 200 in 11 of 15 patients (73.3%) with a mean sweep count of 106 ± 70 (mean ± SD). The calculated mean time to average the potentials could thereby be reduced from 48.8s to 13.7s for mSEPs and from 48.8s to 25.9s for tSEPs. The proposed algorithm allowed sweep count and acquisition time reduction in roughly 90% of all patients for mSEPs and in 70% of all patients for tSEPs.

Non-invasive acquisition of vital data in anesthetized rats using laser and radar application.

The aim of this study was to verify the possibility of obtaining vital sign information using a laser and radar sensor in a manner that is non-invasive and painless for test animals. A dataset was obtained from respiratory movement of anaesthetized male F344 rats, signals of laser and radar sensors were recorded simultaneously with vital data acquired with an integrated multiple-channel intraoperative monitor. In addition, respiratory movements were also video recorded, and used as reference data of respiration rate (RR; ref-RR). Reference data for heart rate (HR; ref-HR) were obtained from the R wave of electrocardiogram data for each epoch. Signals recorded from the radar sensor (I- and Q-signals) were input to a computer, and HR (radar-HR) and RR (radar-RR) were estimated using the frequency analysis method. Among the six positions where respiratory movements were measured by the laser sensor, the number of peak counts matched the visual counts of respiratory movements in the video records. The respiratory movements were significantly the greatest over the most caudal rib in the dorsal (p < 0.001). The average radar-RR and ref-RR values showed correspondence (ref-RR, 69 ± 6.2 breaths/min; radar-RR, 68 ± 5.7 breaths/min (p = 0.04-1.00); equivalence ratio, 86%). The radar-HR data showed slight variability; however, there was 80% homology compared with the ref-HR values (ref-HR, 336 ± 19.6 beats/min; radar-HR, 348 ± 34.1 (p = 0.10-0.95)). Although comparison of the data under noradrenaline administration failed to track drug-induced changes in some cases, the HR and RR data of anesthetized rats measured from the radar sensor system showed comparable accuracy to other conventional methods.

Application of AI integrated semi-autonomous robotics in spine surgery: A review

Spine surgery is a high-risk surgery associated with high precision and accuracy. Artificial intelligence (AI) and semi-autonomous robotics can benefit the surgery. This paper explores the impact of AI and robotics on improving surgical precision, accuracy, and safety with details on preoperative planning, optimal screw placement, and intraoperative real-time monitoring. In addition, the potential of AI-driven simulation spaces for training and skill assessment was evaluated. Various AI models and robotic systems have improved surgical outcomes by providing precise guidance and reducing human error. This review aims to summarize the recent developments and highlight the challenges of AI and semi-autonomous robotics in spine surgery.

Enhancing Caudal Analgesia in Pediatrics: A Comparison of Ropivacaine With and Without Clonidine for Infra-Umbilical Surgeries.

Introduction Regional anesthesia, particularly caudal blocks, is increasingly used in pediatric surgeries for effective post-operative pain management. However, the duration of analgesia with agents such as ropivacaine alone can be limited. This study investigates the effects of adding clonidine to ropivacaine in caudal blocks for pediatric patients undergoing infra-umbilical surgeries, with the purpose of enhancing the duration and quality of analgesia. Methods We conducted a randomized, double-blind study including 50 children aged one to eight years, divided equally into two groups: group R received 0.2% ropivacaine and group RC received 0.2% ropivacaine with 2 mcg/kg clonidine. Intraoperative and post-operative monitoring included heart rate, blood pressure, and respiratory parameters. Analgesia duration, sedation scores, and the need for rescue analgesia were assessed. Results Group RC exhibited significantly longer analgesia duration (18.4 ± 2.31 hours) compared to group R (10.56 ± 2.27 hours, P < 0.0001). Fewer patients in group RC required a second dose of rescue analgesia (4% vs. 32%, P = 0.023), with no significant differences in sedation scores or adverse effects between the groups. Conclusion Adding clonidine to ropivacaine in caudal blocks significantly prolongs analgesia and reduces the need for additional post-operative pain management in pediatric surgeries without increasing the risk of side effects. This study supports the use of clonidine as an effective adjuvant in pediatric pain management.

Intraoperative monitoring of visual evoked potentials: experience of 240 operations

Background. Intraoperative monitoring (IOM) of visual evoked potentials (VEPs) is used to inform surgeons about impacts on the visual system in order to prevent iatrogenic visual impairment. The VEP monitoring use become widespread only in the last decade; nowadays, there is no generally accepted methodology for its implementation, and the effectiveness of VEP monitoring and the factors determining it have not been sufficiently studied.Aim. The aim of the study was to investigate the factors influencing the VEP monitoring feasibility and effectiveness.Materials and methods. Data from 240 consecutive neurosurgical operations performed using VEP monitoring were retrospectively reviewed. IOM data (registration parameters, presence and type of VEP changes), patient characteristics (gender and age, tumor type and location, presence of preoperative visual dysfunctions), anesthesia parameters and postoperative changes in vision were studied. Statistical analysis was performed using χ2 and Mann–Whitney tests.Results. VEPs were obtained in 91.3 % of eyes with completely or partially preserved vision. The main factors reducing the chances to record VEPs successfully are preoperative visual disorders and the use of inhalation anesthesia. A personalized approach to the selection of reference electrodes and frequency filtering parameters makes it possible to reduce the number of averagings required for VEP recording and accelerate informing surgeons. With successful monitoring 59.1 % of eyes had no noticeable VEP changes; 5.8 % of eyes had signs of intraoperative improvement; 35.1 % had signs of deterioration. Among the last category, 60.7 % of eyes had full VEPs recovery afterwards. After surgery, new visual disorders were detected in 2.6 % of eyes without signs of intraoperative deterioration, in 6.7 % – with temporary deterioration, and in 19.3 % – with signs of deterioration persisted until IOM is finished. Assessing the sensitivity and specificity of VEP monitoring is hampered by the possibility of complications in the early postoperative period and IOM influence on the course and results of the operation. The proportion of total resections was maximal when VEP monitoring was successful. In the subgroup without preoperative visual impairments, the alarms during monitoring were associated with decrease in proportion of total resections proportion due to increase in proportion of subtotal resections.Conclusion. VEP monitoring with a personalized approach allows effective monitoring of visual functions preservation during neurosurgical operations.

Cerebral oximetry in high-risk surgical patients: where are we?

This review aims to summarize the latest evidence on the role of near-infrared spectroscopy (NIRS) in monitoring cerebral oxygenation in high-risk surgical patients, including both cardiac and noncardiac surgeries, and to present a new algorithm for its application. NIRS effectively measures brain oxygen saturation noninvasively, proving valuable in cardiac surgeries to reduce neurological complications, though its impact on nonneurological outcomes is less clear. In noncardiac surgeries, NIRS can help prevent complications like postoperative cognitive dysfunction, particularly in high-risk and major surgeries. Studies highlight the variability of cerebral oxygenation impacts based on surgical positions, with mixed results in positions like the beach chair and sitting positions. A structured algorithm for managing cerebral desaturation has been proposed to optimize outcomes by addressing multiple factors contributing to blood oxygen content and delivery. Despite its limitations, including spatial resolution and interindividual variability, NIRS is a useful tool for intraoperative cerebral monitoring. Further studies are needed to confirm its broader applicability in noncardiac surgeries, but current evidence supports its role in reducing postoperative complications especially in cardiac surgeries.

Management of anesthesia in elderly patients, special considerations and challenges

Introduction: Anesthesia management in elderly patients presents distinct challenges due to physiological changes related to aging. Comorbidities, physical frailty and increased risk of postoperative complications are important aspects to be considered. Methods: Systematic reviews of the literature and analyzes of clinical and experimental studies that addressed the management of anesthesia in elderly patients were carried out. Articles published in English, Spanish and Portuguese were selected. The keywords used were "anesthesia in the elderly", "preoperative assessment", "anesthetic techniques", "intraoperative monitoring", "postoperative pain control" and "prevention of complications". Results: Comprehensive and individualized preoperative assessment was identified as crucial for identifying and treating comorbidities and physical frailty in elderly patients. The choice of the appropriate anesthetic technique depends on the type of surgery and the patient's clinical conditions. Careful monitoring during anesthesia, including blood pressure, heart rate, oxygenation and capnography, is essential to detect and intervene early on hemodynamic and respiratory changes. Postoperative pain control in the elderly requires an individualized approach, with appropriate use of analgesics and regional blocks. Complication prevention strategies, such as optimizing hydration, glycemic control, early mobilization and appropriate use of medications, are essential to reduce the risk of delirium, infection and cognitive dysfunction. Conclusion: Anesthesia management in elderly patients requires an individualized and comprehensive approach, taking into account physiological changes related to aging and associated comorbidities. Careful preoperative assessment, appropriate choice of anesthetic technique, strict intraoperative monitoring, postoperative pain control and prevention of complications are essential to ensure a safe perioperative period and successful recovery in the elderly. Keywords: anesthesia in the elderly, preoperative assessment, anesthetic techniques, intraoperative monitoring, postoperative pain control, prevention of complications.

Effectiveness of intraoperative nerve monitoring in reducing rates of recurrent laryngeal nerve injury in aerodigestive and cardiovascular pediatric surgery

ObjectiveTo investigate the effectiveness of intraoperative nerve monitoring at decreasing vocal fold movement impairment in children undergoing at-risk procedures. BackgroundChildren undergoing aerodigestive or cardiovascular procedures are at risk for recurrent laryngeal nerve injury, leading to vocal fold movement impairment. Although intraoperative nerve monitoring has been shown to decrease recurrent laryngeal nerve injury in adults, there is paucity of data in children. MethodsThis was a retrospective, single-center cohort study of children who underwent airway, esophageal, or great vessel surgery between 2018 and 2023. Vocal fold movement impairment was evaluated with pre- and postoperative awake flexible fiberoptic laryngoscopy. Vocal fold movement impairment rates and associated characteristics were compared between those with and without intraoperative nerve monitoring. ResultsAmong 387 children undergoing 426 at-risk procedures, intraoperative nerve monitoring was used in 72.1% (n = 307) of procedures. Intraoperative nerve monitoring significantly reduced postoperative vocal fold movement impairment compared with those without (11.4% vs 20.2%, P = .019, 43.6% relative risk reduction, number needed to treat: 12). In children with a pre-existing vocal fold movement impairment (n = 79, 18.5%), intraoperative nerve monitoring provided enhanced protection (vocal fold movement impairment 7.8% with intraoperative nerve monitoring compared with 25% without, P = .046, 68.6% relative risk reduction, number needed to treat: 3). Bilateral vocal fold movement impairment was 14 times more likely without intraoperative nerve monitoring (1.8% overall, 0.3% with intraoperative nerve monitoring, 5.6% without; 95% confidence interval 1.6–123.2; P = .006). Increasing intraoperative nerve monitoring use correlated with decreasing vocal fold movement impairment rates year over year (P = .046). Multivariable logistic regression demonstrated intraoperative nerve monitoring to remain significantly associated with reduced risk of vocal fold movement impairment (odds ratio, 0.48; 95% confidence interval, 0.26–0.85; P = .013). ConclusionIntraoperative nerve monitoring in children seems effective at decreasing recurrent laryngeal nerve injury and consequently vocal fold movement impairment. Intraoperative nerve monitoring should be considered in children undergoing cervicothoracic or cardiothoracic procedures, especially in those with preoperative vocal fold movement impairment.