Elsevier

World Neurosurgery

Volume 113, May 2018, Pages 67-72
World Neurosurgery

Doing More with Less
Technical Aspects of Awake Craniotomy with Mapping for Brain Tumors in a Limited Resource Setting

https://doi.org/10.1016/j.wneu.2018.02.013Get rights and content

Highlights

  • Intra-axial tumors in or near eloquent brain are associated with neurologic deficit.

  • Awake craniotomy (AC) with mapping is useful for localization of eloquent brain.

  • Stimulation techniques vary among centers, yet no method has proved to be superior.

  • Effective and low-cost techniques are preferable in resource-limited settings.

  • We describe our AC protocol in such conditions hoping to encourage others.

Background

Brain tumor surgery near or within eloquent regions is increasingly common and is associated with a high risk of neurologic injury. Awake craniotomy with mapping has been shown to be a valid method to preserve neurologic function and increase the extent of resection. However, the technique used varies greatly among centers. Most count on professionals such as neuropsychologists, speech therapists, neurophysiologists, or neurologists to help in intraoperative patient evaluation. We describe our technique with the sole participation of neurosurgeons and anesthesiologists.

Methods

A retrospective review of 19 patients who underwent awake craniotomies for brain tumors between January 2013 and February 2017 at a tertiary university hospital was performed. We sought to identify and describe the most critical stages involved in this surgery as well as show the complications associated with our technique.

Results

Preoperative preparation, positioning, anesthesia, brain mapping, resection, and management of seizures and pain were stages deemed relevant to the accomplishment of an awake craniotomy. Sixteen percent of the patients developed new postoperative deficit. Seizures occurred in 24%. None led to awake craniotomy failure.

Conclusions

We provide a thorough description of the technique used in awake craniotomies with mapping used in our institution, where the intraoperative patient evaluation is carried out solely by neurosurgeons and anesthesiologists. The absence of other specialized personnel and equipment does not necessarily preclude successful mapping during awake craniotomy. We hope to provide helpful information for those who wish to offer function-guided tumor resection in their own centers.

Introduction

Surgery is an important treatment component for intra-axial brain tumors. However, resections that take place within or near presumably eloquent areas carry a greater risk of developing a neurologic deficit.1, 2, 3 Literature regarding glioma surgery shows that there is increasing evidence that the extent of resection positively affects overall survival, progression-free survival, and malignant transformation (low grades) to a point that even supratotal resections have been advocated.4, 5, 6, 7, 8, 9, 10, 11, 12 In metastatic disease, as a result of advances in systemic oncologic treatment and longer survival, the involvement of eloquent areas has become more frequent.13 Therefore, given the indisputable role of surgery in the management of these diseases, surgeons treat more and more challenging cases, bearing in mind that an overly aggressive tumor resection may lead to undesirable deficit.

Awake craniotomy (AC) with brain mapping is considered the gold standard for intraoperative localization of eloquent brain. Because anatomic landmarks are not reliable in predicting function,14 stimulation mapping is an outstanding tool for the identification of eloquence in real time. It allows a function-guided resection, reducing the incidence of neurologic deficit and increasing the resection.15 In addition, AC has been shown to be safe and cost effective and to yield high levels of patient satisfaction.16, 17

Despite brain mapping being well established, surgical, anesthesiologic, and stimulation techniques vary considerably among centers. Some institutions count on trained neuropsychologists, speech therapists, neurophysiologists, and neurologists to help intraoperative evaluation of patients during awake surgery.18 Conversely, many neuro-oncologic centers around the world (ours included) do not have access to these professionals or to the technology that they master.

The purpose of this study was to describe a tested AC protocol in a limited resource setting, with the sole participation of neurosurgeons and anesthesiologists.

Section snippets

Methods

A retrospective review of 19 patients who underwent AC for brain tumors between January 2013 and February 2017 at a tertiary university hospital was performed.

In our department, AC was performed in patients with supratentorial intrinsic brain tumor near or within presumed language and/or sensorimotor areas. Untreated psychiatric condition, claustrophobia, patient's refusal, and severely impaired preoperative function were considered contraindications to this method.

We sought to identify and

Results

The following stages were deemed relevant to the accomplishment of an AC. We provide a thorough description of the technique used in each and show complications related to this protocol.

Discussion

In this article, we present the techniques applied in what we judged the most critical stages of an AC. Many centers have described their own experiences but often, adaptations to the local setting are necessary. In our institution, for instance, the AC team comprises solely neurosurgeons and anesthesiologists. We do not count on advanced neurophysiologic techniques such as evoked potentials, electromyography, or electrocorticography. We also show the complications related to this technique.

The

Conclusions

We provide a thorough description of the technique used in a limited resource institution, where intraoperative evaluation of patients is carried out solely by neurosurgeons and anesthesiologists. The absence of professionals such as neurophysiologists, neurologists, neuropsychiatrists, or speech therapists does not necessarily preclude mapping during AC. We hope to provide helpful information for those who wish to offer function-guided tumor resection in their own centers.

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      Leal et al.19 proposed in a recent publication a protocol of awake craniotomy carried out solely by neurosurgeons and anesthesiologists, which is of great interest to centers suffering from a lack of human resources. A new postoperative deficit, regardless of its transitory or permanent nature, was noticed in 16% of their patients, but the cognitive functions were not assessed.19 Regarding our series, a detailed cognitive assessment could be performed in only 5 patients.

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    Conflict of interest statement: The authors declare that the article content was composed in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

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