Intraoperative neurosonography revisited: effective neuronavigation in pediatric neurosurgery

The role of intraoperative ultrasound in gross total resection of brain mass lesions and outcome

Background

Surgical resection of brain mass lesion mandates safety and the best outcome for the patient.

Objectives

The aim of this study was the evaluation of intraoperative ultrasound (IOUS) in gross total resection of brain mass lesions and patients’ safety in comparison to conventional surgery.

Materials and methods

In total, 632 patients were operated for brain mass lesion resection at Neurosurgery Department, Zagazig University Hospitals, during the period from January 2011 to October 2018 and divided randomly into two groups, IOUS group and conventional group, for the detection value of IOUS in resection, safety, and outcome after 3 months follow-up.

Results

The IOUS group showed statistically significant gross total resection regardless to pathology, location, size, age, and sex in favor of IOUS use, and also, there were significantly less complications and better outcome after 3 months follow-up with the IOUS group. Significantly better outcome was found with gross total resection in total surgeries.

Conclusions

The use of IOUS during brain mass lesion surgery is safe and can assist the surgeon in gross total resection with better outcome.

Demonstrative study of brain anatomical landmarks by intraoperative ultrasound imaging

Objectives

Intraoperative use of ultrasound in brain surgery needs good understanding of the brain anatomy in ultrasound images. This study aims to compare ultrasound imaging of brain anatomical landmarks during surgery to perioperative computed tomography (CT), and perioperative magnetic resonance imaging (MRI) as demonstration for encouraging usage as low cost, available and hazardless device.

Methods

In total; 350 patients were subjected to brain surgeries under ultrasound guidance using 2.5–8 megahertz (MHZ) transducers, at neurosurgery department Zagazig university hospital from January 2012 to January 2019. Brain anatomical landmarks were compared between ultrasound images, and perioperative images for safe, and confident surgeries.

Results

Various intracranial anatomical landmarks could be well-demonstrated by ultrasound through the open fontanel, or once the skull was opened, and during surgical work in real time fashion, facilitating surgical procedures, and avoiding complications.

Conclusion

Real-time ultrasound is of great help during brain surgeries in delineating brain anatomical landmarks as well as MRI, and CT brain. The growing learning standard of intraoperative ultrasound (IOUS) use makes brain surgery more simple with avoiding brain shift problems, radiation exposure, and high cost of other intraoperative modalities.

Application of fluorescein sodium in breast cancer brain-metastasis surgery

Objective

Surgical resection serves an important role in the multidisciplinary treatment of cerebral metastases (CMs). Conventional white-light, microsurgical, and circumferential stripping of CMs is standard neurosurgical procedure, but is associated with a high recurrence rate. Based on this outcome, there is an urgent need for a new surgical strategy, such as fluorescence-guided resection, for CMs, in order to achieve total removal.

Methods

A retrospective study was carried out in 38 patients clinically and pathologically diagnosed with breast cancer brain metastasis at three medical centers from May 2012 to June 2016. The study comprised group 1 (fluorescein-guided surgery) and group 2 (standard microsurgery). In group 1, 5 mg/kg of fluorescein sodium was injected intravenously after an allergy test and before general anesthesia for 17 patients. A yellow 560 filter was employed for microsurgical tumor resection. Group 2 consisted of 21 patients for whom fluorescein was not administered.

Results

Surgical outcomes were assessed concerning the extent of resection and Karnofsky performance status. Gross total resection was achieved in these patients, with high fluorescence markedly enhancing tumor visibility. The extent of resection had a powerful influence on performance status. Overall survival after CM was 24.1 months in patients given fluorescein and was 22.8 months in the nonfluorescein group.

Conclusion

Fluorescein-guided surgery is a simple, safe, and practical method to resect breast cancer brain metastasis, and leads to a higher proportion of resection compared to common microsurgery. This offers a tremendous advantage when navigating a tiny tumor, and improves the quality of life of patients with CM.

Intraoperative definition of bottom-of-sulcus dysplasia using intraoperative ultrasound and single depth electrode recording - A technical note

Bottom of sulcus dysplasias (BOSDs) are localized focal cortical dysplasias (FCDs) centred on the bottom of a sulcus that can be highly epileptogenic, but difficult to delineate intraoperatively. We report on a patient with refractory epilepsy due to a BOSD, successfully resected with the aid of a multimodal surgical approach using neuronavigation based on MRI and PET, intraoperative ultrasound (iUS) and electrocorticography (ECoG) using depth electrodes. The lesion could be visualized on iUS showing an increase in echogenicity at the grey-white matter junction. IUS demonstrated the position of the depth electrode in relation to the lesion. Depth electrode recording showed almost continuous spiking. Thus, intraoperative imaging and electrophysiology helped confirm the exact location of the lesion. Post-resection ultrasound demonstrated the extent of the resection and depth electrode recording did not show any epileptiform activity. Thus, both techniques helped assess completeness of resection. The patient has been seizure free since surgery. Using a multimodal approach including iUS and ECoG is a helpful adjunct in surgery for BOSD and may improve seizure outcome.

USim: A New Device and App for Case-Specific, Intraoperative Ultrasound Simulation and Rehearsal in Neurosurgery. A Preliminary Study

BACKGROUND

Intraoperative ultrasound (iUS) is an excellent aid for neurosurgeons to perform better and safer operations thanks to real time, continuous, and high-quality intraoperative visualization.

OBJECTIVE

To develop an innovative training method to teach how to perform iUS in neurosurgery.

METHODS

Patients undergoing surgery for different brain or spine lesions were iUS scanned (before opening the dura) in order to arrange a collection of 3-dimensional, US images; this set of data was matched and paired to preoperatively acquired magnetic resonance images in order to create a library of neurosurgical cases to be studied offline for training and rehearsal purposes. This new iUS training approach was preliminarily tested on 14 European neurosurgery residents, who participated at the 2016 European Association of Neurosurgical Societies Training Course (Sofia, Bulgaria).

RESULTS

USim was developed by Camelot and the Besta NeuroSim Center as a dedicated app that transforms any smartphone into a “virtual US probe,” in order to simulate iUS applied to neurosurgery on a series of anonymized, patient-specific cases of different central nervous system tumors (eg, gliomas, metastases, meningiomas) for education, simulation, and rehearsal purposes. USim proved to be easy to use and allowed residents to quickly learn to handle a US probe and interpret iUS semiotics.

CONCLUSION

USim could help neurosurgeons learn neurosurgical iUS safely. Furthermore, neurosurgeons could simulate many cases, of different brain/spinal cord tumors, that resemble the specific cases they have to operate on. Finally, the library of cases would be continuously updated, upgraded, and made available to neurosurgeons.

Pediatric Spinal Ultrasound: Neonatal and Intraoperative Applications

The purpose of this article is to review the use of ultrasound as a screening tool for spinal diseases in neonates and infants and its intraoperative value in selected pediatric neurosurgical disorders. A review of spinal embryology followed by a description of common spinal diseases in neonates assessed with ultrasound is presented. Indications for spinal ultrasound in neonates, commonly identified conditions, and the importance of magnetic resonance imaging in selected cases are emphasized. Additionally, the use of ultrasound in selected neurosurgical spinal diseases in pediatric patients is presented with magnetic resonance imaging and intraoperative correlation. Technique, limitations, and pitfalls are discussed.

Correlation between intraoperative ultrasound and postoperative MRI in pediatric tumor surgery

OBJECTIVE Malignant disease of the CNS is the primary etiology for deaths resulting from cancer in the pediatric population. It has been well documented that outcomes of pediatric neurosurgery rely on the extent of tumor resection. Therefore, techniques that improve surgical results have significant clinical implications. Intraoperative ultrasound (IOUS) offers real-time surgical guidance and a more accurate means for detecting residual tumor that is inconspicuous to the naked eye. The objective of this study was to evaluate the correlation of extent of resection between IOUS and postoperative MRI. The authors measured the correlation of extent of resection, negative predictive value, and sensitivity of IOUS and compared them with those of MRI. METHODS This study consisted of a retrospective review of the medical charts of all pediatric patients who underwent neurosurgical treatment of a tumor between August 2009 and July 2015 at Albany Medical Center. Included were patients who were aged ≤ 21 years, who underwent brain or spinal tumor resection, for whom IOUS was used during the tumor resection, and for whom postoperative MRI (with and without contrast) was performed within 1 week of surgery. RESULTS Sixty-two patients met inclusion criteria for the study (33 males, mean age 10.0 years). The IOUS results very significantly correlated with postoperative MRI results (φ = 0.726; p = 0.000000011; negative predictive value 86.3% [95% CI 73.7%-94.3%]). These results exemplify a 71% overall gross-total resection rate and 80% intended gross-total resection rate with the use of IOUS (i.e., excluding cases performed only for debulking purposes). CONCLUSIONS The use of IOUS may play an important role in achieving a greater extent of resection by providing real-time information on tumor volume and location in the setting of brain shift throughout the course of an operation. The authors support the use of IOUS in pediatric CNS tumor surgery to improve clinical outcomes at low cost with minimal additional operating-room time and no identified additional risk.

The value of intraoperative ultrasonography during the resection of relapsed irradiated malignant gliomas in the brain

Purpose

The aim of this study was to investigate whether intraoperative ultrasonography (IOUS) helped the surgeon navigate towards the tumor as seen in preoperative magnetic resonance imaging and whether IOUS was able to distinguish between tumor margins and the surrounding tissue.

Methods

Twenty-five patients suffering from high-grade gliomas who were previously treated by surgery and radiotherapy were included. Intraoperatively, two histopathologic samples were obtained a sample of unequivocal tumor tissue (according to anatomical landmarks and the surgeon’s visual and tactile impressions) and a small tissue sample obtained using a navigated needle when the surgeon decided to stop the resection. This specimen was considered to be a boundary specimen, where no tumor tissue was apparent. The decision to take the second sample was not influenced by IOUS. The effect of IOUS was analyzed semi-quantitatively.

Results

All 25 samples of unequivocal tumor tissue were histopathologically classified as tumor tissue and were hyperechoic on IOUS. Of the boundary specimens, eight were hypoechoic. Only one harbored tumor tissue (P=0.150). Seventeen boundaries were moderately hyperechoic, and these samples contained all possible histological results (i.e., tumor, infiltration, or no tumor).

Conclusion

During surgery performed on relapsed, irradiated, high-grade gliomas, IOUS provided a reliable method of navigating towards the core of the tumor. At borders, it did not reliably distinguish between remnants or tumor-free tissue, but hypoechoic areas seldom contained tumor tissue.

Fluorescein sodium-guided surgery in cerebral lymphoma

OBJECTIVES

Growth and progress of primary central nervous lymphoma (PCNSL) severely disrupt the blood brain barrier (BBB). Such disruptions can be intraoperatively visualized by injecting fluorescein sodium (FL) and applying a YELLOW 560 nm surgical microscope filter. Here, we report a small cohort of patients with PCNSL that mimicked high grade gliomas (HGG) or cerebral metastases (CM), who had been operated on with the use of FL.

PATIENTS AND METHODS

Retrospectively, seven patients with PCNSL were identified, who had been operated on by means of microsurgery after intravenous FL injection. The surgical reports were screened for statements on the grade of fluorescent staining in the tumor area. One representative case was chosen to show the staining under white light as well as under filtered light at different distances to the tumor area.

RESULTS

All patients had shown bright and homogenous fluorescent staining of the tumor (n=7. 100%). No adverse effects had been observed.

CONCLUSION

Similar to patients with HGG or CM, patients with PCNSL may benefit from use of FL and the dedicated YELLOW 560 nm filter in open surgery.

A simple, safe and effective surface marking and targeting method combined with intraoperative ultrasonography for small subcortical intracranial lesions

BACKGROUND

Accurately locating small subcortical brain lesions is very important for maximal surgical resection with minimal neurological damage. Intraoperative MRI has proved to be more precise than ultrasound, it is relatively expensive and is not available in all centers. Herein we describe a new, simple, safe and effective method for determining a small skin incision and craniotomy via skin staples combined with intraoperative ultrasonography to determine the margins, vascularity and residue of the lesion.

METHODS

Thirty-three patients with small subcortical lesions were admitted into the study. The maximum diameter of the lesions ranged between 18 and 30 mm. The depth of the lesion was described as the distance between the cortical surface and most outer point of the lesion. The mean of the depth of the lesions was 10.56 mm ranging between 3.3 and 18.7 mm. Multiple skin staples were used as irremovable skin markers. Before and after dural incision, ultrasound was used to assess the lesion size and location, its relationship with the surrounding tissue and the Doppler function to reveal the blood supply to the lesion.

RESULTS

In this study mean craniotomy diameter was 44 mm ranging between 32-55 mm. The location, extent, characteristics and adjacent tissue of the lesion were observed by high frequency ultrasonography during the operation.

CONCLUSIONS

We describe a simple, safe and effective method for determining a small skin incision and craniotomy combined with intraoperative ultrasound for small subcortical intracranial lesions for health center that does not have intraoperative MRI and navigation systems.