Application of intraoperative ultrasonography for guiding microneurosurgical resection of small subcortical lesions

Transcortical transcatheter ultrasound-assisted technique for deep-seated brain tumors. Technical note

PURPOSE

Surgery of deep-seated brain tumors can be challenging. Several methods have been described to facilitate transcortical approaches, including ultrasound-assisted resection. Ultrasound-guided placement of a standard ventricular catheter is a widely reported technique and has been used to approach these lesions via the transcortical route. We describe how we usually perform this useful technique to assist and enhance the transcortical resection of some deep-seated brain tumors.

METHODS

Standard electromagnetic frameless navigation (S8 Neuronavigation System, Medtronic, Minneapolis, USA) was employed to focus the craniotomy and to plan the trajectory of the ventricular catheter. After dural opening, an ultrasound device (Arietta 850, Hitachi-Aloka Medical, Tokyo, Japan) was used for intraoperative ultrasound (IOUS) assessment. A ventricular catheter was placed from the cortex to the lateral wall of the tumor under direct real-time IOUS visualization to guide the further transcortical dissection.

RESULTS

Transcortical transcatheter ultrasound-assisted technique involved minimal time and infrastructure requirements. There were no major technical difficulties during its use, providing confidence and improving subcortical white matter dissection by guiding the route to the tumor.

CONCLUSIONS

Recent improvement of IOUS image-quality devices offers several attractive options for real-time navigation. The combination of conventional neuronavigation systems with real-time IOUS assessment during the intradural step provides a higher degree of control by improving the execution of the surgery. We hope this description may be a useful tool for some selected cases and contribute to the further enhancement and improvement of this widely used technique.

Emergency Intraoperative Ultrasound for the Neurosurgical Trainee

The use of intraoperative ultrasound in emergency cranial neurosurgical procedures is not well described. It may improve surgical outcomes and is useful when other neuro-navigation systems are not readily available. We provide a practical guide for neurosurgical trainees to utilize ultrasound for various emergency cranial neurosurgical procedures, including lesion localization, insertion of an external ventricular drain, and shunt revision surgery. Intraoperative ultrasound is a useful modality for urgent neurosurgical procedures.

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.

Intraoperative contrast-enhanced ultrasound for cerebral glioma resection and the relationship between microvascular perfusion and microvessel density

We analyzed the relationship between quantitative CEUS parameters and microvessel density (MVD) of different pathologic grades of cerebral gliomas. ICEUS was performed in 49 patients with cerebral gliomas. The enhancement characteristics of cerebral gliomas were observed before and after tumor resection. The number of microvessels was counted by immunostaining with anti-CD34. Differences in these quantitative parameters in cerebral gliomas were compared and subjected to a correlation analysis with MVD. The assessment of iCEUS parameters and tumor MVD showed that cerebral gliomas of different pathological grades had different characteristics. The time-to-peak (Tmax) was significantly shorter, the peak intensity (PI) and MVD were significantly higher in high-grade cerebral gliomas than in low-grade cerebral gliomas (p < 0.05). According to the immunostaining, PI was positively (r = 0.637) correlated with MVD and Tmax was negatively (r = -0.845) correlated with MVD. ICEUS could provid dynamic and continuous real-time imaging and quantitative data analysis of different pathological grades of cerebral gliomas, the quantitiative CEUS parameters were closely related to the MVD, and be helpful in understanding the cerebral gliomas grade and refining surgical strategy.

Non-enhancing gliomas: does intraoperative ultrasonography improve resections?

PURPOSE

Non-enhancing diffuse gliomas are a challenging surgical proposition. Delineation of tumour extent on preoperative imaging and intraoperative visualization are often difficult.

METHODS

We retrospectively analyzed all cases of non-enhancing gliomas that were operated on using navigated 3-dimensional ultrasonography (US). Tumour delineation (good, moderate, or poor) on preoperative magnetic resonance imaging (MRI) and intraoperative US was compared. Post-resection US findings with respect to residual tumour status were compared to the postoperative imaging findings. The extent of resection was calculated and recorded.

RESULTS

There were 55 gliomas (43 high-grade, 12 low-grade). Forty were close to eloquent areas. The pre-resection concordance of MRI with US was 56%, with US defining more tumours as well-delineated (n=26) than MRI (n=13). US was used for resection control in 50 cases. Gross tumour resection was achieved in 24 cases (51%). US correctly predicted the residual tumour status in 78% of cases. The use of US led to radical resections even in some tumours preoperatively deemed to be unresectable. However, eloquent location was the only independent predictor of the extent of resection.

CONCLUSION

Intraoperative US is a useful tool for guiding resection of non-enhancing gliomas. It may be better than MRI for delineating these tumours, and may thereby facilitate improved resection of these otherwise poorly delineated tumours. However, functional boundaries remain the main limiting factor for achieving complete resection of non-enhancing gliomas.

Intraoperative imaging techniques for glioma surgery

Gliomas are CNS neoplasms that infiltrate the surrounding brain parenchyma, complicating their treatment. Tools that increase extent of resection while preventing neurological deficit are essential to improve prognosis of patients diagnosed with gliomas. Tools such as intraoperative MRI, ultrasound and fluorescence-guided microsurgery have been used in the surgical resection of CNS gliomas with the goal of maximizing extent of resection to improve patient outcomes. In addition, emerging experimental techniques, for example, optical coherence tomography and Raman spectroscopy are promising techniques which could 1 day add to the increasing armamentarium used in the surgical resection of CNS gliomas. Here, we present the potential advantages and limitations of these imaging techniques for the purposes of identifying gliomas in the operating room.

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.

Middle cerebral arterial flow changes on transcranial color and spectral Doppler sonography in patients with increased intracranial pressure

OBJECTIVES

Intracranial pressure usually increases after severe brain injury. However, a method for noninvasive evaluation of intracranial pressure is still lacking. The purpose of this study was to explore the potential role of transcranial color Doppler sonography in assessing intracranial pressure by observing the middle cerebral artery blood flow parameters in patients with increased intracranial pressure of varying etiology.

METHODS

The hemodynamic changes in the middle cerebral artery in patients with varying degrees of increased intracranial pressure were investigated by transcranial color Doppler sonography in 93 patients who had emergency surgery for brain injury.

RESULTS

Middle cerebral artery Doppler flow spectra changed regularly as intracranial pressure increased. The pulsatility index (PI) and resistive index (RI) had a significantly positive correlation with intracranial pressure (r = 0.90 and 0.89, respectively; P< .001), whereas the middle cerebral artery diastolic velocity showed a significant negative correlation with intracranial pressure (r = -0.52; P< .01). A receiver operating characteristic curve showed that the RI and PI cutoff values were 0.705 and 1.335, respectively, for predicting increased intracranial pressure, with sensitivity of 0.885 and specificity of 0.970.

CONCLUSIONS

In addition to the PI and RI, middle cerebral artery diastolic flow velocity measurement by transcranial color Doppler sonography may also be a useful variable for evaluating intracranial pressure in patients with acute brain injury.

Relationship of intraoperative ultrasound characteristics with pathological grades and Ki-67 proliferation index in intracranial gliomas

OBJECTIVE

The purpose of the present study was to investigate the relationship between the intraoperative ultrasonographic appearances and the histopathological characteristics of glial tumors using the pathological grading system and the Ki-67 proliferation index.

MATERIALS AND METHODS

Patients with glial tumors who underwent surgery with the aid of intraoperative ultrasonography (IOUS) between September 2013 and August 2014 were included in the study. The lesions' IOUS characteristics were analyzed and compared with the results of surgical histopathological characteristics. Lesions were classified as low-grade gliomas (grade I-II, LGG) and high-grade gliomas (grade III-IV, HGG). The glioblastoma multiforme (grade IV, GBM) group was classified according to the Ki-67 values for further evaluation. The Chi square test (Fisher's exact test) was used for comparing the ultrasonographic characteristics of the low-grade and high-grade gliomas; HGG with different Ki-proliferation indexes. A value of P < 0.05 was considered statistically significant.

RESULTS

A total of 41 patients were included. The histopathological findings revealed 15 LGG and 26 HGG. Twenty of the 26 HGG were GBM. Differences were found between the intraoperative ultrasonographic characteristics of the low-grade and high-grade glial tumors. The majority of LGGs were mildly hyperechoic and homogeneous, with distinct margins and a regular contour. HGGs were mostly highly hyperechoic, with indistinct margins, irregular contours, and a heterogeneous internal texture. Surrounding edema was seen more often in HGGs. The differences in the echogenicity of the solid parts, the internal echo patterns, margins, contours, and peripheral edema (P < 0.05) were statistically significant, but the difference in the presence of cysts (P > 0.05) was not significant. In the GBM group, all of the lesions with distinct margins and regular contours had Ki-67 values ≤15 %. We compared the intraoperative ultrasonographic characteristics of the Ki-67 > 15 % group with those of the Ki-67 ≤ 15 % group for statistical significance. The difference between the echogenicity of the solid parts, margins, and contours was statistically significant between the groups (P < 0.05). The difference in the internal echo pattern, presence of cyst, and peripheral edema was insignificant (P > 0.05).

CONCLUSIONS

IOUS is a very useful imaging technique not only in defining the borders but also in characterizing the tumoral tissue. The IOUS characteristics of the glial tumors were a valuable tool in differentiating the grades of the glial tumors and might have a relationship with the Ki-67 proliferation index. We think this theory requires further investigation in more detailed comparative studies with larger numbers of patients.

High-frequency intra-operative ultrasound-guided surgery of superficial intra-cerebral lesions via a single-burr-hole approach

The study described here examined the feasibility of using high-frequency intra-operative ultrasound (hfioUS) guidance to resect superficial intra-cerebral lesions through a single burr hole. A cohort of 23 consecutive patients with a total of 24 intra-cerebral lesions (9 intra-cerebral metastases, 8 gliomas, 4 infections, 2 lymphomas and 1 cavernoma) were studied. All lesions could be localized and successfully resected, biopsied or aspirated, and histopathological diagnoses were obtained in all cases. The mean operating time was 59.6 ± 23.9 min. The mean cross-sectional lesion size was 6.4 ± 7.6 cm(2), and the mean cortex surface-to-lesion distance was 0.6 ± 0.8 cm. Our results illustrate the feasibility of identifying and resecting superficial intra-cerebral lesions under hfioUS guidance via a single-burr-hole approach. We were able to achieve short resection times with no post-operative complications in all patients, favorable conditions under which to start adjuvant therapy when indicated.