A Concise Guide to D-Wave Monitoring during Intramedullary Spinal Cord Tumour Surgery.

D-waves (also called direct waves) result from the direct activation of fast-conducting, thickly myelinated corticospinal tract (CST) fibres after a single electrical stimulus. During intraoperative neurophysiological monitoring, D-waves are used to assess the long-term motor outcomes of patients undergoing surgery for intramedullary spinal cord tumours, selected cases of intradural extramedullary tumours and surgery for syringomyelia. In the present manuscript, we discuss D-wave monitoring and its role as a tool for monitoring the CST during spinal cord surgery. We describe the neurophysiological background and provide some recommendations for recording and stimulation, as well as possible future perspectives. Further, we introduce the concept of anti D-wave and present an illustrative case with successful recordings.

Assessment of the Benefit of Intraoperative Cortical Stimulation in Patients with Lesions within Eloquent Brain Regions / Avaliação do benefício da estimulação cortical intraoperatória em pacientes com lesões em áreas cerebrais eloquentes

Objective The present study sought to evaluate the benefits of intraoperative cortical stimulation (CS) for reducing morbidity in neurosurgery. Method A total of 56 patients were submitted to neurosurgical procedure with the aid of CS. Initially, surgical exposure and planned resection were based on anatomy and imaging exams, which were followed by CS. According to the findings, the patients were divided into two groups. In group 1 the previous surgical strategy had to be altered, while in group 2 the surgical planning did not suffer any interference. Patients were also divided into subgroups according to the underlying disease: gliomas or other etiologies. Transient and definitive deficits occurrence were compared between groups 1 and 2 and subgroups of etiologies. The real benefit of CS technique was calculated by a specific formula. Results There were 20 patients (37.5%) whose surgical strategy was changed based on CS findings. Furthermore, 65% of group 1 patients had transient deficit, in comparison to 30.5% of patients in group 2 (p » 0.013). As for the definitive deficit, it occurred in 15.0% of group 1 patients versus 8.3% of patients in group 2 (p » 0.643). Definitive deficits with no statistical difference (p » 0.074) were found in 17.2% of patients with gliomas, while none were found in the other etiologies subgroup. The rate of real benefit of intraoperative CS was 30.4%. Considering the subgroups of gliomas and other etiologies, the benefit rates were 25.7% and 38.1%, respectively. Conclusions The surgical decision was influenced by CS in 35.7% of the cases and prevented definitive deficit in 30% of patients.

Objetivos O presente estudo procurou avaliar os benefícios da estimulação cortical (EC) intraoperatória na redução da morbidade em neurocirurgias. Métodos Um total de 56 pacientes foram submetidos ao procedimento neurocirúrgico com ajuda da EC. Inicialmente, a exposição cirúrgica e o panejamento da ressecção eram baseados nos achados de anatomia e imagem, que eram seguidos pela EC. De acordo com os achados neurofisiológicos, os pacientes foram divididos em dois grupos. No grupo 1, a estratégia cirúrgica teve que ser modificada, enquanto no grupo 2, o planejamento cirúrgico não foi alterado. Os pacientes foram ainda divididos em dois subgrupos de acordo com a doença subjacente: gliomas ou outras etiologias. A ocorrência de déficits transitórios e definitivos foram comparadas entre os grupos 1 e 2 e entre os subgrupos de etiologias. O benefício real da técnica de estimulação cortical foi calculado por uma fórmula específica. Resultados A estratégia cirúrgica foi alterada em 20 (37,5%) pacientes após a estimulação cortical. Além disso, 65% dos pacientes do grupo 1 tiveram déficits transitórios, em comparação com 30,5% dos pacientes do grupo 2 (p » 0,013). Quanto ao déficit definitivo, este ocorreu em 15% dos casos do grupo 1 contra 8,3% dos pacientes do grupo 2 (p » 0,643). Déficit definitivo sem diferença significativa (p » 0,074) foi observado em 17,2% dos pacientes com gliomas, enquanto nenhum foi encontrado no subgrupo de outras etiologias. A taxa de benefício real da EC intraoperatória foi de 30,4%. Considerando os subgrupos de gliomas e outras etiologias as taxas de benefício foram 25,7% e 38,1%, respectivamente. Conclusões A EC influenciou a decisão cirúrgica em 35,7% dos casos. Embora 90% dos pacientes não tenham cursado com déficits a longo prazo, a estimulação cortical preveniu tais déficits em cerca de um terço deles.

Microvascular decompression for hemifacial spasm: Complications after 292 procedures without neurophysiological monitoring.

Background: Hemifacial spasm (HFS) is characterized by involuntary, progressive, and intermittent spasms in the upper and lower facial muscles. Due to the high success rate, microvascular decompression (MVD) is the treatment of choice, and intraoperative neuromonitoring (INM) is considered useful for achieving safe surgery. Still, most centers do not have this technology. Methods: We analyzed 294 patients with HFS treated with MVD without INM. We only included patients with a neurovascular etiology while excluding other causes, such as tumors. As part of the postoperative evaluation, we assessed preoperative magnetic resonance imaging and pure-tone audiometry. Results: The main complication was peripheral facial paralysis in 50 patients, followed by hypoacusis in 22 patients and deafness in 17 patients, associated with a failed surgical outcome (P = 0.0002). The anterior inferior cerebellar artery (AICA) was an offending vessel, and the involvement of more than one vessel was significantly associated with the development of facial nerve palsy (P = 0.01). AICA was also associated with hearing impairment (P = 0.04). Over 90% of immediate complications improve in the follow-up (6 months), and one patient did not show a cure for initial HFS. Conclusion: MVD is the method with the highest long-term cure rates for treating HFS; however, we must inquire into the multiple factors of the patient and the surgeon to predict surgical outcomes. INM is not a must during MVD for HFS. We recommend its use depending on the availability and mainly on the surgeon's skills, for surgeons.

Comparison of onset of neuromuscular blockade with electromyographic and acceleromyographic monitoring: a prospective clinical trial.

BACKGROUND: Reliable devices that quantitatively monitor the level of neuromuscular blockade after neuromuscular blocking agents' administration are crucial. Electromyography and acceleromyography are two monitoring modalities commonly used in clinical practice. The primary outcome of this study is to compare the onset of neuromuscular blockade, defined as a Train-Of-Four Count (TOFC) equal to 0, as measured by an electromyography-based device (TetraGraph) and an acceleromyography-based device (TOFscan). The secondary outcome was to compare intubating conditions when one of these two devices reached a TOFC equal to 0. METHODS: One hundred adult patients scheduled for elective surgery requiring neuromuscular blockade were enrolled. Prior to induction of anesthesia, TetraGraph electrodes were placed over the forearm of patients' dominant/non-dominant hand based on randomization and TOFscan electrodes placed on the contralateral forearm. Intraoperative neuromuscular blocking agent dose was standardized to 0.5 mg.kg-1 of rocuronium. After baseline values were obtained, objective measurements were recorded every 20 seconds and intubation was performed using video laryngoscopy once either device displayed a TOFC = 0. The anesthesia provider was then surveyed about intubating conditions. RESULTS: Baseline TetraGraph train-of-four ratios were higher than those obtained with TOFscan (Median: 1.02 [0.88, 1.20] vs. 1.00 [0.64, 1.01], respectively, p < 0.001). The time to reach a TOFC = 0 was significantly longer when measured with TetraGraph compared to TOFscan (Median: 160 [40, 900] vs. 120 [60, 300] seconds, respectively, p < 0.001). There was no significant difference in intubating conditions when either device was used to determine the timing of endotracheal intubation. CONCLUSIONS: The onset of neuromuscular blockade was longer when measured with TetraGraph than TOFscan, and a train-of-four count of zero in either device was a useful indicator for adequate intubating conditions. CLINICAL TRIAL NUMBER AND REGISTRY: URL NCT05120999, https://clinicaltrials.gov/ct2/show/NCT05120999.

Comparison of onset of neuromuscular blockade with electromyographic and acceleromyographic monitoring: a prospective clinical trial

Abstract Background Reliable devices that quantitatively monitor the level of neuromuscular blockade after neuromuscular blocking agents' administration are crucial. Electromyography and acceleromyography are two monitoring modalities commonly used in clinical practice. The primary outcome of this study is to compare the onset of neuromuscular blockade, defined as a Train-Of-Four Count (TOFC) equal to 0, as measured by an electromyography-based device (TetraGraph) and an acceleromyography-based device (TOFscan). The secondary outcome was to compare intubating conditions when one of these two devices reached a TOFC equal to 0. Methods One hundred adult patients scheduled for elective surgery requiring neuromuscular blockade were enrolled. Prior to induction of anesthesia, TetraGraph electrodes were placed over the forearm of patients' dominant/non-dominant hand based on randomization and TOFscan electrodes placed on the contralateral forearm. Intraoperative neuromuscular blocking agent dose was standardized to 0.5 mg.kg−1 of rocuronium. After baseline values were obtained, objective measurements were recorded every 20 seconds and intubation was performed using video laryngoscopy once either device displayed a TOFC = 0. The anesthesia provider was then surveyed about intubating conditions. Results Baseline TetraGraph train-of-four ratios were higher than those obtained with TOFscan (Median: 1.02 [0.88, 1.20] vs. 1.00 [0.64, 1.01], respectively, p < 0.001). The time to reach a TOFC = 0 was significantly longer when measured with TetraGraph compared to TOFscan (Median: 160 [40, 900] vs. 120 [60, 300] seconds, respectively, p < 0.001). There was no significant difference in intubating conditions when either device was used to determine the timing of endotracheal intubation. Conclusions The onset of neuromuscular blockade was longer when measured with TetraGraph than TOFscan, and a train-of-four count of zero in either device was a useful indicator for adequate intubating conditions. Clinical trial number and registry URL NCT05120999, https://clinicaltrials.gov/ct2/show/NCT05120999.

Intraoperative neurophysiological monitoring in Latin America: A bibliometric analysis.

PURPOSE: Intraoperative Neurophysiological Monitoring (IOMM) has been used worldwide in the attempt to reduce postsurgical neurological deficits, however, most of the publications are from developed countries. There is a global bibliometric analysis of IOMN in spinal surgery, however, the contribution of Latin America (LA) is not mentioned. The aim of this study is to describe scientific productivity, patterns of publications, and thematic trends of IONM in LA. METHODS: Data was collected using Scopus database, by searching scientific articles with LA affiliation, using 18 keywords. We excluded duplicates, not original articles, reviews, surveys, and articles not related to humans. Articles were analyzed and classified as follows: year of publication, language of the original document, journals metrics, country, IONM modality, etiology, location of surgery, medical specialties, and outcome. Descriptive statistics were used. RESULTS: We obtained 8,699 scientific articles of which 41 scientific articles from 7 LA countries were selected. Mexico has the highest number of publications. In most countries, supratentorial location showed the highest frequency. Somatosensory evoked potentials and electrocorticography were the most performed modalities. Neurosurgery was the most involved specialty of our 41 scientific articles, and 95.1% of these publications concluded that IONM is useful to guide surgical procedures. CONCLUSIONS: Mexico and Brazil have led IONM publications in LA. The lower reference in publications of visual evoked potentials and brainstem auditory evoked potentials IONM modalities, could be considered in the future to boost tailored research in LA.

Somatosensory evoked potentials in clinical practice: a review / Potenciais evocados somatossensitivos na prática clínica: uma revisão

Abstract The authors present a review of the current use of somatosensory evoked potentials (SSEPs) in neurological practice as a non-invasive neurophysiological technique. For this purpose we have reviewed articles published in English or Portuguese in the PubMed and LILACS databases. In this review, we address the role of SSEPs in neurological diseases that affect the central nervous system and the peripheral nervous system, especially in demyelinating diseases, for monitoring coma, trauma and the functioning of sensory pathways during surgical procedures. The latter, along with new areas of research, has become one of the most important applications of SSEPs.

Resumo Os autores apresentam uma revisão do uso atual do potencial evocado somatossensitivo (PESS) na prática neurológica como uma técnica neurofisiológica não invasiva. Revisamos artigos publicados em Inglês ou Português nas bases de dados PubMed e LILACS. Nesta revisão abordamos o papel do PESS nas doenças neurológicas que atingem o sistema nervoso central e o sistema nervoso periférico, especialmente, nas doenças desmielinizantes, no monitoramento do coma, do trauma e da função das vias sensitivas durante os procedimentos cirúrgicos, que se tornou uma de suas aplicações mais importantes, assim como novas áreas de pesquisa.

Double neurophysiological certification of the filum terminale during sectioning surgery in pediatric population.

BACKGROUND: Surgery of thickened-fibrolipoma filum terminale (FT) is performed routinely and without conflict but is not a risk-free surgical procedure. Intraoperative neurophysiological monitoring with mapping techniques can help to certify the FT before sectioning. However, a tailored surgical approach to cauda equina and a low threshold of surrounding nerve roots can confuse the final surgical decision. The aim is to demonstrate the usefulness of this double methodology for FT certification. METHODS: A prospective study collected and reviewed retrospectively, from 2015 to 2018, 40 patients undergoing an FT surgery section were included in the study. After opening the dura mater and under the microscope, the cauda equina mapping is performed and the recording of muscles of the lower limbs and the external anal sphincter. In addition, a high-intensity stimulation of constant current of an isolated FT for a short period of time and in a dry surgical field, obtaining a bilateral-polyradicular-symmetrical response of cauda equina nerve roots. RESULTS: Traditional motor mapping identified FT in 65% (26/40) of patients. Although, 35% (14/40) of the patients still have low-intensity stimuli response (<1 mA) of a muscle, especially anal sphincter. When this happens, the optimization of the dissection around FT is performed. After that, 25% (10/40) of the patients still having a muscle response in spite of seem isolated FT. Increasing the stimulation intensity up to 20 mA evoked a cauda equina response in all cases. No postoperative neurological impairment was observed in this series. CONCLUSION: This proposed methodology accurately confirms the FT so that it can be safely found and cut. The Double Neurophysiological Certification improves the gap of the traditional mapping techniques of cauda equina and can be used in a variety of more complex surgeries in this area.

Diagnostic accuracy of perioperative electromyography in the positioning of pedicle screws in adolescent idiopathic scoliosis treatment: a cross-sectional diagnostic study.

BACKGROUND: To investigate in the conventional techniques of the pedicle screws using triggered screw electromyography (t-EMG), considering different threshold cutoffs: 10, 15, 20 25 mA, for predicting pedicle screw positioning during surgery of the adolescent with idiopathic scoliosis (AIS). METHODS: Sixteen patients (4 males, 12 females, average age 16.6 years) were included, with an average curve magnitude of 50 degrees and placement of 226 pedicle screws. Each screw was classified as "at risk for nerve injury" (ARNI) or "no risk for nerve injury" (NRNI) using CT and the diagnostic accuracy of EMG considering different threshold cutoffs (10,15, 20 and 25 mA) in the axial and Sagittal planes for predicting screw positions ARNI was investigated. RESULTS: The EMG exam accuracy, in the axial plane, 90.3% screws were considered NRNI. In the sagittal plane, 81% pedicle screws were considered NRNI. A 1-mA decrease in the EMG threshold was associated with a 12% increase in the odds of the screw position ARNI. In the axial and sagittal planes, the ORs were 1.09 and 1.12, respectively. At every threshold cutoff evaluated, the PPV of EMG for predicting screws ARNI was very low in the different threshold cutoff (10 and 15); the highest PPV was 18% with a threshold cutoff of 25 mA. The PPV was always slightly higher for predicting screws ARNI in the sagittal plane than in the axial plane. In contrast, there was a moderate to high NPV (78-93%) for every cutoff analyzed. CONCLUSIONS: EMG had a moderate to high accuracy for positive predicting value screws ARNI with increase threshold cutoffs of 20 and 25 mA. In addition, showed to be effective for minimizing false-negative screws ARNI in the different threshold cutoffs of the EMG in adolescent with idiopathic scoliosis (AIS).

Barriers of neurophysiology monitoring in spine surgery: Latin America experience.

BACKGROUND: Intraoperative neurophysiological monitoring (IOM) has become valuable in spine surgery. Unfortunately, it is not always available in many spine centers, especially in developing countries. Our aim was to evaluate the accessibility and barriers to IOM in spine surgery in Latin America. METHODS: We designed a questionnaire to evaluate the characteristics of surgeons and their opinions on the usefulness of IOM for different spine operations. The survey was sent to 9616 members and registered users of AO Spine Latin America (AOSLA) from August 1, 2019, to August 21, 2019. Major variables studied included nationality, years of experience, specialty (orthopedics or neurosurgery), level of complexity of the hospital, number of spine surgeries performed per year by the spine surgeon, the types of spinal pathologies commonly managed, and how important IOM was to the individual surgeon. General questions to evaluate use included accessibility, limitations of IOM usage, management of IOM changes, and the legal value of IOM. The results were analyzed and compared between neurosurgeon and orthopedics, level of surgeon experience, and country of origin. RESULTS: Questionnaires were answered by 200 members of AOSLA from 16 different countries. The most common responses were obtained from orthopedic surgeons (62%), those with more than 10 years of practice (54%); majority of surgeons performed more than 50 spine surgeries per year (69%) and treated mainly spine degenerative diseases (76%). Most surgeons think that IOM has a real importance during surgeries (92%) and not just a legal value. Although surgeons mostly considered IOM essential to scoliosis surgery in adolescents (70%), thoracolumbar kyphosis correction (68%), and intramedullary tumors (68%), access to IOM was limited to 57% for economic reasons. Of interest, in 64% of cases, where IOM was available and significant change occurred, the actual operative procedures were significantly altered. CONCLUSION: Despite the fact that 68% of spine surgeons believe IOM to be indispensable for complex spine surgery, cost remains the main barrier to its use/availability in Latin America.

Anterolateral S1 screw malposition detected with intraoperative neurophysiological monitoring during posterior lumbosacral fusion.

BACKGROUND: The standard of care is to utilize intraoperative neurophysiological monitoring (IOM) of triggered electromyography (tEMG) during posterior lumbosacral instrumented-fusion surgery. IOM should theoretically signal misplacement of S1 screws into the neural L5-S1 foramen or spinal canal, utilizing screw stimulation, and recording of the lower limb muscles and the anal sphincter. Here, we evaluated when and whether anterolateral S1 screw malposition could be detected by IOM/tEMG during open posterior lumbosacral instrumented fusion surgery. METHODS: tEMG, somatosensory-evoked potential (SSEP), and transcranial electrical motor-evoked potential (TcMEP) data were retrospectively reviewed from 2015 to 2017 during open posterior lumbosacral instrumented fusions. We utilized screw stimulation alert thresholds of <14 mA (tEMG) and recorded from the lower extremity muscles and anal sphincter. Furthermore, all patients underwent routine postoperative computed tomography (CT) scans to confirm the screw location. RESULTS: There were 106 S1 screws placed in 54 patients: 52 bilateral and 2 unilateral. In 6 patients (11.1%), 7 screws (6.6%) registered at low tEMG thresholds. In 1 patient, the postoperative CT scan documented external malposition of the screw despite no intraoperative IOM/tEMG alert. When S1 misplaced screws were stimulated, the most sensitive muscle was the tibialis anterior; the sensitivity of the IOM/tEMG was 87.5%, the specificity was 97.9%, the positive predictive value was 77.8%, and the negative predictive value was 98.9%. TcMEP and SSEP did not change during any of the operations. Notably, no patient developed a new neurological deficit. CONCLUSION: Anterolateral S1 screw malposition can be detected accurately utilizing IOM/tEMG stimulation of screws. When alerts occur, they can largely be corrected by partially backing out the screw (e.g., a few turns) and/ or changing the screw trajectory.

Traumatic spondyloptosis of L3 with incomplete neurological involvement: A case report.

High-energy traumas frequently result in lumbar spine fractures such as spondyloptosis is the maximum expression of instability and severity. The management of spondyloptosis is complex and, essentially, surgical. It usually presents with irreversible neurological compromise. This paper aimed to present a case of lumbar spondyloptosis and its early confrontation, partial neurological involvement, and progressive postoperative retrieval. CLINICAL CASE: A male patient aged 42 years had multiple injuries with asymmetric paraparesis and sphincter involvement. Computed tomography (CT) revealed L3 vertebral spondyloptosis detached from the rest of the spine, spinal canal stenosis, sagittal imbalance, and angular kyphosis. Surgical resolution was defined by performing an en bloc corpectomy through lumbotomy and the installation of an expandable cage with posterior transpedicular fixation of L2-L4, thereby recovering the spinal canal diameter, lumbar lordosis, sagittal balance, and improving motor function progressively. CONCLUSION: Complex spinal injuries warrant an early resolution by a trained surgical team to ensure normal spinal parameters and to achieve a progressive neurological recovery.

Upper thoracic dumbbell-shaped tumor resected in one stage posterior approach: case report.

Upper thoracic tumors may develop spinal cord compression. By surgery at the time of diagnosis, a neurological deficit can be avoided. However, this particular localization requires a double approach to decompress the spinal cord and thoracic structures. The posterior extracavitary approach results in resection of the spinal canal, the foraminal component, and the extraspinal fragment, but is not routinely used by most neurosurgeons. A 56-year-old woman with a two-month history of axial thoracic pain and cough. The patient has a normal neurological examination. Thoracic computed tomography (CT) scan with contrast agent was performed, evincing a dumbbell-shaped tumor on the left T3-T4. Magnetic resonance imaging (MRI) confirms the diagnosis, showing a 4 cm diameter tumor that compresses the spinal cord without myelopathy. The surgery was performed posteriorly, with costotransversectomy, allowing complete resection under intraoperative neurophysiological monitoring. The patient developed no thoracic or neurological complications. One-stage posterior approach is possible and effective during the treatment of the upper thoracic dumbbell-shaped tumors, avoiding a change in surgical position, thoracic morbidity, and dependence on assisting surgeons.

Neuromonitorización intraoperatoria del nervio facial: a propósito de un caso / Intraoperative neuromonitoring of the facial nerve: a case report

Introdução: A preservação do nervo facial (NF) é uma das principais preocupações do cirurgião durante o tratamento aberto das fraturas mandibulares, uma vez que uma lesão nessa estrutura anatômica pode causar sequelas estéticas e funcionais permanentes. A existência de variações anatômicas (anastomoses e ramificações incomuns) aumenta o risco de danos no NF, mesmo nas mãos de cirurgiões experientes. O neuromonitoramento intraoperatório tem-se mostrado um grande aliado para evitar lesões nos ramos nervosos que podem estar envolvidos na área cirúrgica. Considerando a escassez desse assunto na literatura referente à cirurgia maxilo-facial, objetivamos demonstrar o uso da técnica de neuromonitoração do NF durante o acesso submandibular para o tratamento da fratura bilateral do ângulo mandibular. Relato de caso: No presente relato de caso, as abordagens cirúrgicas de ambos os lados não apresentaram danos permanentes ao NF. Esse resultado assim como a literatura sugerem que o neuromonitoramento intraoperatório proporciona maior segurança durante a realização de abordagens cirúrgicas, nas quais os ramos do nervo facial estão envolvidos, reduzindo, assim, o risco de sequelas nervosas. Considerações Finais: Esse recurso pode ser de grande auxílio no treinamento hospitalar ao longo do processo de formação de cirurgiões bucomaxilofaciais... (AU)

Introduction: Facial nerve (FN) preservation is one of the surgeon's major concerns during the open treatment of mandibular fractures since an injury to this anatomical structure can cause permanent aesthetic and functional sequelae. The existence of anatomical variations (anastomosis and unusual branching) increases the risk of FN damage even in the hands of experienced surgeons. Intraoperative neuromonitoring has proven to be a great ally to avoid injury to the nerve branches that may be involved in the surgical area. Considering the scarcity of this subject in the maxillofacial surgery literature, we aimed to demonstrate the use of the FN neuromonitoring technique during the submandibular approach for the treatment of bilateral mandibular angle fracture. Case report: In the present case report, the surgical approaches of both sides presented no permanent damage to the FN. Results: This result, as well as previous literature, suggests that intraoperative neuromonitoring provides greater safety during the performance of surgical approaches in which the facial nerve branches are involved and thus, reduces the risk of nerve sequelae. Final considerations: This resource can be of special assistance in teaching hospitals throughout the training process of maxillofacial surgeons... (AU)

[Implementation of intraoperative neurophysiologic monitoring in children and adults in secondary and tertiary health care facilities]. / Implementación del monitoreo neurofisiológico intraoperatorio en niños y adultos en el segundo y tercer nivel de atención.

INTRODUCTION: Intraoperative neurophysiological monitoring (IONM) is a procedure that uses neurophysiological techniques in order to evaluate the motor and sensitive systems during surgeries that endanger the nervous system. METHOD: The approach, scope, target population, and clinical questions to be answered were defined. A systematic search of the evidence was conducted step by step; during the first stage, clinical practice guidelines were collected, during the second stage systematic reviews were obtained, and during the third stage, clinical trials and observational studies were procured. The MeSH nomenclature and free related terminology were used, with no language restrictions and a 5-10 years frame. The quality of the evidence was graded using the CEPD and SIGN scales. RESULTS: Obtained using the search algorrhythms of 892 documents. Fifty-eight were chosen to be included in the qualitative synthesis. A meta-analysis was not possible due to the heterogeneity of the studies. CONCLUSIONS: Eighteen recommendations were issued and will support the adequate use of the IONM.

INTRODUCCIÓN: El monitoreo neurofisiológico intraoperatorio (MNIO) es un procedimiento que emplea técnicas neurofisiológicas con la finalidad de evaluar los sistemas motor y sensitivo durante cirugías que ponen en riesgo al sistema nervioso. MÉTODO: Se definieron el enfoque, los alcances, la población diana y las preguntas clínicas por resolver. Se realizó una búsqueda sistematizada de la evidencia por etapas. En la primera, se buscaron guías de práctica clínica; en la segunda, revisiones sistemáticas; y en la tercera, ensayos clínicos y estudios observacionales. Se utilizaron los términos MeSH y libres correspondientes, sin restricciones de lenguaje y con una temporalidad de 5 a 10 años. Se graduó la calidad de la evidencia utilizando las escalas CEPD y SIGN. RESULTADOS: Mediante los algoritmos de búsqueda se obtuvieron 892 documentos, y se seleccionaron 58 para la inclusión de la síntesis cualitativa. Debido a la heterogeneidad entre los estudios, no fue posible realizar metaanálisis. CONCLUSIONES: Se emitieron 18 recomendaciones, las cuales servirán como apoyo para la adecuada utilización del MNIO.

Injury of the external branch of the superior laryngeal nerve in thyroid surgery.

The external branch of the superior laryngeal nerve (EBSLN) innervates the cricothyroid muscle (CTM) to promote lengthening and thinning of the vocal fold, thus increasing voice pitch. The close relation with the superior thyroid vessels (STV) puts the EBSLN in risk every time the superior pole of the thyroid is dissected. It travels downward to innervate the CTM, lateral to the thyroid cartilage and to the inferior pharyngeal constrictor muscle (IPCM), being eventually covered by this muscle fibers as it approaches its entry point. During its descending course, the EBSLN curves and crosses the STV posteriorly. The lower this crossing occurs in the neck, the higher the risk of surgical damage to the nerve by transection, traction, entrapment, thermal damage or disrupted blood supply. The chances of surgical trauma are also increased by size and weight of the specimen, shorter neck length and non-white ethnicity. Voice changes following thyroid surgery are common and multifactorial. The actual rate of vocal impairment due to EBSLN injury is unclear, since changes to the everyday speaking voice can be minimal and laryngeal findings are usually subtle and controversial. CTM electroneuromyography (EMG) is the most accurate tool to diagnose abnormal EBSLN conductivity, but it is technically difficult and barely applicable in routine practice. Recommended approaches to prevent injury include: (I) individual distal ligature of the STV by the thyroid capsule; (II) visual identification of the nerve and its trajectory and (III) electrostimulation with either observation of CTM twitch or intraoperative nerve monitoring (IONM) via dedicated endotracheal tube electrodes. There is accumulating evidence that a combination of visual and standardized electrophysiological EBSLN identification with meticulous division of the STV improves preservation rates. IONM bears the additional benefits of prognostication, quantification and documentation of neural function once it allows intraoperative laryngeal EMG.

Intraoperative Neurophysiological Monitoring for Spinal Fusion

The surgical techniques of spinal fusion are frequently used in the treatment of many spine conditions. Apart from having anatomical knowledge, in order to perform those procedures safely, it is essential to utilize all the tools available to assure the appropriate positioning of the materials and avoid neural injury. The goal of this article is to review the literature on the use of intraoperative neurophysiological monitoring for spinal fusion procedures and to discuss the controversies regarding this issue.

As técnicas cirúrgicas de fusão espinhal são frequentemente utilizadas no tratamento de muitas condições da coluna vertebral. Além do conhecimento anatômico, para realizar esses procedimentos com segurança é essencial utilizar todas as ferramentas disponíveis para assegurar o posicionamento adequado dos materiais e evitar lesões neurais. O objetivo deste artigo é revisar a literatura sobre o uso de monitorização neurofisiológica intraoperatória para procedimentos de fusão espinhal e discutir as controvérsias relacionadas a essa questão.

Positioning of pedicle screws in adolescent idiopathic scoliosis using electromyography / Posição de parafusos pediculares na escoliose idiopática do adolescente com uso da eletromiografia / Posición de tornillos pediculares en escoliosis idiopática del adolescente con electromiografía

To analyze the occurrence of poor positioning of pedicle screws inserted with the aid of intraoperative electromyographic stimulation in the treatment of Adolescent Idiopathic Scoliosis (AIS).

Analisar a ocorrência do mau posicionamento de parafusos pediculares inseridos com auxílio de estimulação eletromiográfica intraoperatória, no tratamento de escoliose idiopática do adolescente (EIA).

Analizar la incidencia de la mala colocación de tornillos pediculares insertados con la ayuda de la estimulación electromiográfica intraoperatoria para el tratamiento de la Escoliosis Idiopática del Adolescente (EIA).

Valor predictivo de la estimulación eléctrica de los tornillos pediculares torácicos en la mal posición medial de los mismos en la instrumentación de cirugía de columna / Valor preditivo da estimulação elétrica em casos de mal posicionamento de parafusos pediculares torácicos na cirurgia de coluna / Predictive value of electrical stimulation in cases of malposition of thoracic pedicle screws in spine surgery

OBJETIVO: Demostrar si la técnica de estimulación eléctrica permite la detección de la mal posición medial de los tornillos pediculares torácicos. RESULTADOS: Se analizaron 421 tornillos torácicos. Tuvimos alertas a la estimulación en 25 (5,93%) de los casos. A todos los pacientes se les realizó radiografía posoperatoria demostrando 22 tornillos (5,2%) medializados. Realizamos TAC en 17 pacientes (37%), con ningún tornillo en posición 1 y 10 tornillos en posición 2 (8,5%). Se consideraron tornillos medializados los que tenían respuesta positiva a estimulación inferior a 6 mA. CONCLUSIONES: la estimulación eléctrica nos ha permitido reducir el riesgo de posición medial de los tornillos torácicos, minimizando además el uso de radiografía intraoperatoria.

OBJETIVO: Demonstrar se a técnica de estimulação elétrica permite a detecção de mal posicionamento medial dos parafusos pediculares torácicos. RESULTADOS: Foram analisados 421 parafusos torácicos. Os alertas da estimulação ocorreram em 25 (5,93%) dos casos. Todos os pacientes foram submetidos à radiografia pós-operatória que demonstrou 22 parafusos (5,2%) medializados. Realizamos TC axial em 17 pacientes (37%), e não se encontrou nenhum parafuso na posição 1, sendo que 10 parafusos estavam na posição 2 (8,5%). Foram considerados parafusos medializados os que apresentaram resposta positiva à estimulação inferior a 6 mA. CONCLUSÕES: a estimulação elétrica permitiu a redução de risco de posição medial dos parafusos torácicos, minimizando o uso de radiografias intraoperatórias.

OBJECTIVE: To demonstrate that the electrical stimulation technique allows the detection of medial malpositioning of thoracic pedicle screws. RESULTS: We analyzed 421 thoracic screws. Stimulation alerts occurred in 25 (5.93%) cases. All patients underwent postoperative radiographs showing 22 medialized screws (5.2%). Axial CT scans were performed on 17 patients (37%), and no screw was found in position 1 and 10 of them were in position 2 (8.5%). Medialized screws were considered those who had a positive response to stimulation of less than 6 mA. CONCLUSIONS: Electrical stimulation allowed a reduction of risk of medial positioning of thoracic screws, minimizing the use of intraoperative radiographs.

Monitoreo neurofisiológico intraoperatorio en Pediatría: controversias actuales / Intraoperative neurophysiological monitoring in pediatrics: Current controversies

Introducción: el monitoreo neurofisiológico intraoperatorio es una nueva aplicación de la neurofisiología clínica. Mediante la detección inmediata de alteraciones funcionales durante procedimientos médico-quirúrgicos, pretende minimizar la aparición de lesiones neurológicas. Objetivos: se enumeran sus indicaciones en el paciente pediátrico. Se mencionan sus modalidades estándar y se discuten algunas de las más actuales controversias sobre sus principales indicaciones en éstas edades. Conclusiones: para la selección de las controversias nos valimos de las únicas cuatro revisiones existentes en la literatura. Se concluye que a pesar de tan reciente aplicación, representa una herramienta importante en la prevención y/o reducción de posibles lesiones neurológicas, en cerca del 5% de procedimientos médico-quirúrgicos, buena parte de las cuales, se realizan en pacientes pediátricos. Salud UIS 2012; 44 (1): 7-16.

Introduction: intraoperative neurophysiological monitoring is a new application of clinical neurophysiology. Through the immediate detection of functional alterations during medical or surgical procedures, it pretends to minimize the appearance of neurological lesions. Objetive: its indications in pediatric patients are enumerated. Its standard modalities are mentioned, and, current controversies on some of its most important indications are discussed. Conclusions: for the controversies selection we used the only four existent literature reviews. It is concluded, that despite such a recent application, it represents an important tool in the prevention and/or reduction of possible neurological lesions in close to 5% of medical-surgical procedures, many of these of which, are performed in pediatric patients. Salud UIS 2012; 44 (1): 7-16.