Intraoperative Ultrasonography in Neurosurgery: Experience of an Institution / Ultrassonografia intraoperatória em neurocirurgia: Experiência de uma instituição

Objective Intraoperative ultrasound (IOUS) is an imaging method that can be used in various neurosurgical procedures. It assists in the removal of brain tumors, hematomas, in the insertion of ventricular catheters, and in spinal and peripheral nerve surgeries. The original studies using IOUS were performed with devices that produced lower-quality images, generating little interest in their use. The introduction of ultrasound devices that yielded higher-quality images associated with a relative low cost and ease of use rendered IOUS attractive. Thus, we started using it in multiple neurosurgical procedures, studying its practicality, efficacy and limitations. Materials and methods A retrospective case study on the use of IOUS in neurosurgery from August 2014 to December 2020 at a single institution, evaluating its practicality, efficacy and limitations. Results A total of 127 IOUS scans were performed in 112 patients aged 19 to 83 (mean: 53.8) years: 106 scans of the brain, 4 of the spinal cord, and 2 of the peripheral nerves. Brain tumors were the majority, with 86 cases (67.8%). The IOUS was unsatisfactory in 9 cases (7.1%), and there were no cases of infection related to the IOUS. Conclusion The IOUS is a dynamic, safe, and practical exam. It can be performed in a few minutes and repeated several times during the surgical procedure. It enables surgeons to observe the pulsation of tissues and vessels, the displacement of lumps in liquid collections, and to monitor the drainage of cysts and collections, in vivid, interactive and real-time images.

Objetivo A ultrassonografia intraoperatória (USIO) é um método de imagem que pode ser utilizado em vários procedimentos neurocirúrgicos. Auxilia na remoção de tumores cerebrais, hematomas, no implante de cateteres ventriculares, e em cirurgias espinhais e de nervos periféricos. Os estudos iniciais com a USIO eram realizados com aparelhos que disponibilizavam imagens de baixa qualidade, o que gerava pouco interesse no seu uso. Com o desenvolvimento de aparelhos de ultrassom que produziam imagens de melhor qualidade, eram de fácil manuseio e tinham relativo baixo custo, reacendeu-se o interesse na USIO. Por este motivo, iniciamos a utilização da USIO em múltiplos procedimentos neurocirúrgicos, e estudamos sua praticidade, eficácia e limitações. Materiais e métodos Estudo retrospectivo dos casos em que a USIO foi utilizada em neurocirurgia de agosto de 2014 a dezembro de 2020 em uma só instituição, com a avaliação de sua praticidade, eficácia e limitações. Resultados Foram realizadas 127 USIOs em 112 pacientes com idades entre 19 e 83 (média: 53,8) anos, 106 no encéfalo, 4 em medula espinhal, e 2 em nervo periférico. Os tumores cerebrais foram a maioria, com 86 casos (67,8%). A USIO foi insatisfatória em 9 casos (7,1%), e não houve casos de infecção relacionada à USIO. Conclusões A USIO é um exame dinâmico, seguro e prático. Pode ser feito em poucos minutos e repetido várias vezes durante o procedimento cirúrgico. É possível observar a pulsação dos tecidos e vasos, o deslocamento de grumos em coleções líquidas, e acompanhar a drenagem de cistos e coleções, em imagens vivas, interativas e em tempo real.

Utility of Intraoperative Ultrasound in Neurosurgery

Objective The purpose of the present study is to demonstrate the usefulness of intraoperative ultrasound guidance as a technique for the assessment, in real time, of tumor resection and as a navigation aid during intra-axial brain lesion removal on patients admitted in the Neurosurgical Department at the Hospital Universitario de Caracas, Caracas, Venezuela, in 2018. Methods A total of 10 patients were enrolled, each with intra-axial brain lesions with no previous neurosurgical procedures and a mean age of 49 years old, ranging from 29 to 59 years old. Results A male predominance was observed with 7 cases (70%) over 3 female cases (30%). Six patients had lesions in the dominant hemisphere. The frontal lobe was the most commonly affected,with 5 cases, followed by the parietal lobe,with 4 cases. After craniotomy, ultrasound evaluation was performed previously to dural opening, during tumor resection and after tumor removal. The mean tumor size in axial, coronal and sagittal views was 3.72 cm, 3.08 cm and 3.00 cm, respectively, previously to dural opening with intraoperative ultrasound. The average tumor depth was 1.73 cm from the cerebral cortex. The location and removal duration from the beginning of the approach (ultrasound usage time) was 83.60 minutes, and the average surgery duration was 201 minutes. Navigation with intraoperative ultrasound served to resect intra-axial tumors more precisely and safely. There was no postoperative complication associated with the surgery in this series of cases. Conclusions Intraoperative ultrasound guidance for intra-axial subcortical tumor resection is a technique that serves as a surgical and anatomical orientation tool.

Intraoperative vascular Doppler ultrasound blood flow and peak systolic velocity predict early patency in hemodialysis arteriovenous fistula.

BACKGROUND: Chronic kidney disease is a major public health problem. Hemodialysis is the most common renal replacement therapy. Arteriovenous fistulas (AVF) are a possible access option, but early failure rates remain high. OBJECTIVES: to investigate the value of intraoperative vascular Doppler ultrasound for predicting early AVF patency. METHODS: Prospective observational study. Consecutive patients undergoing AVF were assessed with vascular Doppler ultrasonography intraoperatively and on days 1, 7, 30, and 60. Patients were divided into groups according to presence or absence of primary and secondary patency. Blood flow (BF) and peak systolic velocity (PSV) were compared. ROC curves were plotted and used to define the PSV and BF values that yielded greatest sensitivity (Sens) and specificity (Spec). RESULTS: 47 patients met the inclusion criteria and were analyzed. Higher intraoperative PSV and BF values were observed in patients who had primary and secondary patency than in patients with access failure. The values with greatest sensitivity and specificity for predicting 30-day primary patency were 106 cm/s for venous PSV (Sens: 75% and Spec: 71.4%) and 290.5 ml/min for arterial blood flow (Sens: 80.6% and Spec 85.7%). Values for 30-day secondary patency were 106 cm/s for arterial PSV (Sens: 72.7%, Spec: 100%) and 230 ml/min for venous blood flow (Sens: 86.4%, Spec100%). Values for 60-day primary patency were 106 cm/s for venous PSV (Sens: 74.4%, Spec: 62.5%) and 290.5 ml/min for arterial blood flow (Sens: 80%, Spec: 75%). CONCLUSIONS: Peak systolic velocity and blood flow measured using intraoperative vascular Doppler ultrasound can predict early patency of hemodialysis arteriovenous fistulas.

O volume de fluxo e a velocidade de pico sistólico ao ultrassom vascular com Doppler intraoperatório como preditores de perviedade precoce na fístula arteriovenosa autógena para hemodiálise / Intraoperative vascular Doppler ultrasound blood flow and peak systolic velocity predict early patency in hemodialysis arteriovenous fistula

Resumo Contexto A insuficiência renal crônica é um problema de saúde pública mundial. A hemodiálise é a principal terapia renal substitutiva. As fístulas arteriovenosas (FAV) são uma possível escolha, mas apresentam altas taxas de falência. Objetivos Este estudo tem como objetivo avaliar a relação entre as variáveis hemodinâmicas ao ultrassom vascular com Doppler no intraoperatório e a perviedade precoce da FAV para hemodiálise. Métodos Tratou-se de um estudo prospectivo observacional. Os pacientes consecutivos foram submetidos a FAV com ultrassonografia vascular com Doppler em intraoperatório nos dias 1, 7, 30 e 60. Eles foram divididos em grupos quanto à presença ou não de perviedade primária e secundária, e o volume de fluxo (VF) e a velocidade de pico sistólico (VPS) foram comparados. Foram realizadas curvas receiver operating characteristic (ROC), com definição de valores de VPS e VF com sensibilidade (S) e especificidade (E). Resultados Foram analisados 47 pacientes, os quais preencheram os critérios de inclusão. Os valores de VPS e VF intraoperatório foram maiores nos pacientes com perviedade primária e secundária comparados àqueles com falência. Os seguintes valores apresentaram maiores sensibilidade e especificidade para predizer perviedade primária aos 30 dias: 106 cm/s para VPS venoso, S: 75%, E: 71,4%; e 290,5 mL/min para VF arterial, S: 80,6%, E: 85,7%. Para perviedade secundária aos 30 dias, foram observados: 106 cm/s para VPS arterial, S: 72,7%, E: 100%; e 230 mL/min para VF venoso, com S: 86,4%, E: 100%. Para a perviedade primária no 60º dia, foram observados: 106 cm/s para VPS venoso, S: 74,4%, E: 62,5%; e 290,5 mL/min para VF arterial, S: 80%, E: 75%. Conclusões A velocidade de pico sistólico e o VF ao ultrassom vascular com Doppler intraoperatório são preditores de perviedade precoce na FAV para hemodiálise.

Abstract Background Chronic kidney disease is a major public health problem. Hemodialysis is the most common renal replacement therapy. Arteriovenous fistulas (AVF) are a possible access option, but early failure rates remain high. Objectives to investigate the value of intraoperative vascular Doppler ultrasound for predicting early AVF patency. Methods Prospective observational study. Consecutive patients undergoing AVF were assessed with vascular Doppler ultrasonography intraoperatively and on days 1, 7, 30, and 60. Patients were divided into groups according to presence or absence of primary and secondary patency. Blood flow (BF) and peak systolic velocity (PSV) were compared. ROC curves were plotted and used to define the PSV and BF values that yielded greatest sensitivity (Sens) and specificity (Spec). Results 47 patients met the inclusion criteria and were analyzed. Higher intraoperative PSV and BF values were observed in patients who had primary and secondary patency than in patients with access failure. The values with greatest sensitivity and specificity for predicting 30-day primary patency were 106 cm/s for venous PSV (Sens: 75% and Spec: 71.4%) and 290.5 ml/min for arterial blood flow (Sens: 80.6% and Spec 85.7%). Values for 30-day secondary patency were 106 cm/s for arterial PSV (Sens: 72.7%, Spec: 100%) and 230 ml/min for venous blood flow (Sens: 86.4%, Spec100%). Values for 60-day primary patency were 106 cm/s for venous PSV (Sens: 74.4%, Spec: 62.5%) and 290.5 ml/min for arterial blood flow (Sens: 80%, Spec: 75%). Conclusions Peak systolic velocity and blood flow measured using intraoperative vascular Doppler ultrasound can predict early patency of hemodialysis arteriovenous fistulas.

Intraoperative Ultrasound Navigation with Doppler Function to Guide Arteriovenous Malformation Resection: 3-Dimensional Operative Video.

Intraoperative ultrasound navigation was initially introduced in the neurosurgical field for brain tumor surgery and was then extended to arteriovenous malformation surgery with good success. This tool provides real-time intraoperative images.1 Moreover, Doppler ultrasound permits early identification of feeding arteries and supplies the surgeon with a global impression of the flow dynamics.2 A further use of doppler is to check for residual nidus. Other advantages are the capacity to identify intracerebral hemorrhage.2 In this video, we demonstrate the case of a 15-yr-old patient who presented intracranial hemorrhage. Magnetic resonance imaging revealed the presence of left frontoparietal hematoma associated with an image suggestive of cerebral arteriovenous malformation (AVM). Arteriography confirmed the diagnosis of AVM fed by branches of the anterior cerebral and superficial drainage for the superior sagittal sinus. The patient was placed in dorsal decubitus with his head turned to the right and a left parietal-frontal craniotomy was performed. After the dura mater was opened, cortical mapping was performed to locate the motor and sensory cortex. After the mapping, ultrasound with doppler was performed to locate the AVM and the hematoma and determine its relation to the motor and sensory cortex. At the end of the surgery, doppler ultrasound was used again to ensure complete resection of the AVM. Intraoperative Ultrasound navigation with doppler is an inexpensive technology that can be used in the treatment of AVMs, especially in the subcortex, as it assists in locating the nidus and confirms its complete resection.

Útilidad de la ecografía intraoperatoria en la exéresis de las lesiones no palpables de la mama: experiencia y revisión de conjunto / Usefulness of intraoperative ultrasound in excision of non-lesions palpable of the breast: experience and overview

RESUMEN OBJETIVO: Presentar la experiencia de la unidad de mama de nuestro hospital con la utilización de la ecografía intraoperatoria en el tratamiento de las lesiones no palpables de mama. PACIENTES Y MÉTODO: Se incluyeron aquellas pacientes con lesiones no palpables de mama y ecovisibles. Intraoperatoriamente se localizó la lesión con la ecografía y se procedió a su exéresis, con comprobación ecográfica de su correcta extirpación con márgenes de seguridad. Se realizó estudio macroscópico en fresco de los márgenes marcados con tinta intraoperatoriamente. En caso de que los márgenes no fueran correctos se procedía a una ampliación de márgenes en el mismo acto quirúrgico. RESULTADOS: Desde el año 2012 se han intervenido 52 pacientes. En todas las pacientes se localizó la lesión con la ecografía. Se realizó tumorectomía a 24 pacientes y a 28 pacientes se les asoció la biopsia del ganglio centinela. El resultado patológico definitivo fue de 19 lesiones benignas y 33 lesiones malignas. A una paciente se le realizó mastectomía simple por presentar un carcinoma in situ extenso con microinfiltración no diagnosticado con las pruebas radiológicas preoperatorias. El resto de pacientes presentaron márgenes libres de tumor. CONCLUSIONES: La ecografía intraoperatoria es una técnica simple y fácil de desarrollar. Presenta una baja tasa de afectación de márgenes y es enteramente cirujano-controlada. Es confortable para el paciente y conlleva un bajo riesgo de complicaciones relacionadas con la técnica.

ABSTRACT OBJETIVE: To present the results of our hospital's experience with the utilization of intraoperative ultrasound in the treatment of non-palpable breast lesions. PATIENTS AND METHOD: We included those patients whose breast lesions were non-palpable yet simultaneously visible on ultrasound. The lesions were located intraoperatively with ultrasound and were removed with ultrasound verification of the proper security margins. An examination of the intraoperative macroscopic margins with ink was done. In cases with incorrect margins, a re-excision was done utilizing the same technique but with amplified margins. RESULTS: Dating from 2012, we have operated on 52 patients. In all cases, the lesions were discovered and localized by means of ultrasound. Lumpectomy was performed on 24 patients and we associated the sentinel node biopsy in 28 cases. Subsequent pathology reports determined that 19 lesions were benign and 33 lesions were malignant. There was one patient with a mastectomy because a long extensive ductal carcinoma in situ with microinfiltration that was not seeing during the preoperative study. CONCLUSIONS: Intraoperative ultrasound is an easy and simple technique that is entirely surgeon controlled and results in a low rate of positive margins. The procedure is comfortable for the patient and carries with it a low rate of complications.

Patient-specific model-based segmentation of brain tumors in 3D intraoperative ultrasound images.

PURPOSE: Intraoperative ultrasound (iUS) imaging is commonly used to support brain tumor operation. The tumor segmentation in the iUS images is a difficult task and still under improvement because of the low signal-to-noise ratio. The success of automatic methods is also limited due to the high noise sensibility. Therefore, an alternative brain tumor segmentation method in 3D-iUS data using a tumor model obtained from magnetic resonance (MR) data for local MR-iUS registration is presented in this paper. The aim is to enhance the visualization of the brain tumor contours in iUS. METHODS: A multistep approach is proposed. First, a region of interest (ROI) based on the specific patient tumor model is defined. Second, hyperechogenic structures, mainly tumor tissues, are extracted from the ROI of both modalities by using automatic thresholding techniques. Third, the registration is performed over the extracted binary sub-volumes using a similarity measure based on gradient values, and rigid and affine transformations. Finally, the tumor model is aligned with the 3D-iUS data, and its contours are represented. RESULTS: Experiments were successfully conducted on a dataset of 33 patients. The method was evaluated by comparing the tumor segmentation with expert manual delineations using two binary metrics: contour mean distance and Dice index. The proposed segmentation method using local and binary registration was compared with two grayscale-based approaches. The outcomes showed that our approach reached better results in terms of computational time and accuracy than the comparative methods. CONCLUSION: The proposed approach requires limited interaction and reduced computation time, making it relevant for intraoperative use. Experimental results and evaluations were performed offline. The developed tool could be useful for brain tumor resection supporting neurosurgeons to improve tumor border visualization in the iUS volumes.

Intraoperative ultrasonography for presumed brain metastases: a case series study / Uso de ultrassonografia intraoperatória para metástases cerebrais presumidas: estudo de uma série de casos

Brain metastases (BM) are one of the most common intracranial tumors and surgical treatment can improve both the functional outcomes and patient survival, particularly when systemic disease is controlled. Image-guided BM resection using intraoperative exams, such as intraoperative ultrasound (IOUS), can lead to better surgical results. METHODS: To evaluate the use of IOUS for BM resection, 20 consecutives patients were operated using IOUS to locate tumors, identify their anatomical relationships and surgical cavity after resection. Technical difficulties, complications, recurrence and survival rates were noted. RESULTS: IOUS proved effective for locating, determining borders and defining the anatomical relationships of BM, as well as to identify incomplete tumor resection. No complications related to IOUS were seen. CONCLUSION: IOUS is a practical supporting method for the resection of BM, but further studies comparing this method with other intraoperative exams are needed to evaluate its actual contribution and reliability.

As metástases cerebrais (MC) são os tumores intracranianos mais frequentes e seu tratamento cirúrgico pode melhorar a sobrevida e a funcionalidade do paciente, especialmente quando a doença sistêmica está controlada. A ressecção das MC guiada por imagens de exames intraoperatórios, como ultrassom intraoperatório (USIO), pode levar a melhores resultados cirúrgicos. MÉTODOS: Avaliar o uso do USIO nas ressecções de MC de 20 pacientes para localizar os tumores, avaliar suas relações anatômicas e a cavidade cirúrgica após o procedimento. As dificuldades técnicas, complicações, recorrência e taxa de sobrevivência foram anotadas em cada caso. RESULTADOS: USIO foi eficaz para localizar, delinear e definir as relações anatômicas das MC, assim como a ocorrência de ressecção incompleta. Não foram encontradas complicações relacionadas ao uso do USIO. CONCLUSÃO: USIO é um método auxiliar prático para as ressecções de MC, porém outros estudos ainda se fazem necessários para avaliar sua real contribuição nesses procedimentos.