Intraoperative Ultrasonography of the Brain and Spine

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.

Diagnostic usefulness of intraoperative ultrasonography for unexpected severe brain swelling in ultra-early surgery for ruptured intracranial aneurysms

BACKGROUND

In ultra-early aneurysm surgery, the few hours from admission to aneurysm clipping present the greatest risk for an in-hospital recurrent hemorrhage, the development of acute hydrocephalus, and severe brain edema. Thus, severe brain swelling encountered after dural opening in a craniotomy can sometimes not be explained by a preoperative computed tomography (CT) scan. Therefore, neurosurgeons need a diagnostic tool to determine the exact cause of the brain swelling to apply appropriate intraoperative management. Accordingly, the authors propose a designated optimal ultrasound window for evaluating brain swelling during a pterional craniotomy, and assess its diagnostic usefulness and clinical impact.

METHODS

Intraoperative ultrasonography was performed during pterional craniotomies to identify the causes of severe brain swelling in 23 out of 185 patients treated using a policy of ultra-early treatment after a subarachnoid hemorrhage. Paine's point was used as the sonographic window to provide axial images showing the anterior interhemispheric fissure, lentiform nucleus, insular cortex, sylvian fissure, and ventricular system.

RESULTS

The intraoperative ultrasonography revealed significant changes from the preoperative CT findings in 9 (39.1 %) of the 23 patients. These changes included the occurrence of an intracerebral hemorrhage (ICH, n = 2) related to aneurysm rebleeding with aggravated hydrocephalus and the development (n = 5) or aggravation (n = 2) of acute hydrocephalus without rebleeding. Meanwhile, for 14 (60.9 %) of the 23 patients, the ultrasonography showed no intracranial changes. For the total 23 patients with severe brain swelling, the intraoperative management included aspiration of an ICH (n = 3), a ventriculostomy (n = 16), and medical management (n = 8) with additional mannitol and/or mild hyperventilation.

CONCLUSIONS

When severe brain swelling is encountered during a pterional craniotomy for clipping a ruptured aneurysm, an intraoperative ultrasonography technique using Paine's point as a sonographic window provides useful and reliable diagnostic information on the causes of the brain swelling, enabling the neurosurgeon to select appropriate intraoperative management.

Objective assessment of utility of intraoperative ultrasound in resection of central nervous system tumors: A cost-effective tool for intraoperative navigation in neurosurgery

Background:

Localization and delineation of extent of lesions is critical for safe maximal resection of brain and spinal cord tumors. Frame-based and frameless stereotaxy and intraoperative MRI are costly and not freely available especially in economically constrained nations. Intraoperative ultrasound has been around for a while but has been relegated to the background. Lack of objective evidence for its usefulness and the perceived “user unfriendliness” of US are probably responsible for this. We recount our experience with this “forgotten” tool and propose an objective assessment score of its utility in an attempt to revive this practice.

Materials and Methods:

Seventy seven intraoperative ultrasound (IOUS) studies were carried out in patients with brain and spinal cord tumors. Seven parameters were identified to measure the “utility” of the IOUS and a “utility score” was devised (minimum 0 and maximum 7). Individual parameter and overall scores were calculated for each case.

Results:

IOUS was found to be useful in many ways. The median overall score was 6 (mean score 5.65). There were no scores less than 4 with the majority demonstrating usefulness in 5 or more parameters (91%). The use of the IOUS significantly influenced the performance of the surgery in these cases without significantly prolonging surgery.

Conclusions:

The IOUS is a very useful tool in intraoperative localization and delineation of lesions and planning various stages of tumor resection. It is easy, convenient, reliable, widely available, and above all a cost-effective tool. It should be increasingly used by neurosurgeons in the developing world where costlier intraoperative localization and imaging is not available freely.