Panduranga Seetahal-Maraj1, Narindra Ramnarine1, Patrick Knight2
1Department of Neurosurgery, San Fernando General Hospital
2Department of Neurosurgery, Port-of-Spain General Hospital
Corresponding Author
Dr. Panduranga Seetahal-Maraj
San Fernando General Hospital
Paradise Pastures, Independence Avenue, San Fernando
Email: [email protected]
Copyright: This is an open-access article under the terms of the Creative Commons Attribution License which permits use, distribution, and reproduction in any medium, provided the original work is properly cited.
©2021 The Authors. Caribbean Medical Journal published by Trinidad & Tobago Medical Association
ABSTRACT
Awake craniotomies (AC) are proven to reduce the neurological deficit associated with tumour resection in areas of eloquent cortex. Successful performance requires not only technical skill, but the availability of neuronavigation, cortical mapping, intra-operative frozen section and the appropriate anaesthetic support. This case report describes the first fully awake craniotomy done in Trinidad, at a public hospital, for a patient with seizures secondary to a low-grade glioma. It resulted in an excellent patient outcome, with full cessation of seizures and no postoperative deficits.
CASE REPORT
Tumours of the central nervous system can be a source of significant morbidity and mortality due to the unforgiving nature of the territory that they occupy. The potential for neurological decline or death, particularly in young and otherwise healthy patients, makes resection of these lesions challenging. Particularly in our local setting, many patients view surgery for brain tumour resection as riskier than other types of procedures. However, advances in technology and microsurgery have facilitated safe resection of these lesions with minimal risk to the patient and excellent outcomes. Additionally, performance of awake craniotomies allows us to have real-time monitoring of the effects of tissue manipulation on the patient’s function and allows maximal preservation of eloquent cortex. We present a case which illustrates these principles.
A 30-year-old male presented to the Accident and Emergency department with new-onset generalized tonic-clonic seizures. It was preceded by an aura. No other significant neurologic symptoms were present and the remainder of his history was benign. Physical examination did not reveal any significant positive findings, aside from upgoing plantars on the right. No motor or sensory deficits were present, and cranial nerve examination was normal.
A CT scan of the brain revealed a 3cm x 2cm x 2cm left frontal lesion, anterior to the motor strip. There was no associated vasogenic oedema, nor any synchronous lesions. Administration of contrast did not reveal any enhancement. The radiographic appearance was consistent with a low-grade glioma (LGG).
The patient proceeded to have an MRI Brain pre- and post-gadolinium (Figure 1), and the findings were again strongly suggestive of a primary brain tumour, consistent with a glioma. Post-gadolinium T1-weighted sequences did not reveal any enhancement or uptake of contrast. No significant oedema was found on T2/FLAIR sequences. No other lesions were identified.
Due to the patient’s age and radiographic findings, it was unlikely that the lesion would be a metastatic deposit, and CT of the chest/abdomen/pelvis was not deemed necessary. Anti-epileptics were commenced, and the patient was counselled on the need for tumour excision. Because of the location of this tumour (within eloquent cortex), the potential for creating motor deficits after resection was high. An awake craniotomy with intraoperative cortical mapping was deemed appropriate. The patient underwent extensive counselling and anaesthetic review to determine his fitness for an awake procedure. All potential risks and complications were detailed, and the patient consented to an Awake Craniotomy (AC). Standard preoperative questions were asked to assess neurologic function and the answers recorded. These would be repeated intraoperatively to identify any new neurologic deficit. The questions were based on the tumour’s location (anterior to the motor strip), and included word/sentence repetition, picture naming and performance of certain motor functions.
Figure 1: Top row – Preoperative axial T2 (left) image revealing hyperintense lesion in left frontal lobe, anterior to motor strip, with no evident oedema. Right image is an axial T1 without contrast), which is hypointense relative to surrounding tissue. Bottom row – sagittal(left) and axial(right) T1 post-contrast images, with no enhancement of the lesion. This suggests a low-grade glioma.
Figure 2: Top row – Intraoperative cortical mapping (left) to determine safe entry zone and post-resection (right) tumour bed. Middle row – preoperative(left) and postoperative (right) axial T1 images revealing gross total resection of tumour. Bottom row – postoperative sagittal(left) and axial(right) T1 images showing complete tumour resection, with normal post-craniotomy air pockets in the tumour cavity.
Anti-epileptics (Phenytoin) were given at a loading dose 30 minutes prior to the procedure in anticipation of cortical stimulation and potential evoking of seizures. A left-sided scalp block was performed by the anaesthetic team, followed by incision and pin-site infiltration by the neurosurgery team.
The patient was positioned supine on the operating table and all bony prominences were padded. It was ensured that he was comfortable prior to rigid skull-fixation. The head was rotated 20 degrees to the right to make the tumour the highest point in the operative field. Three-point fixation was then performed, using a Mayfield head-clamp. Attachment of the Neuronavigation (BrainLab) apparatus to the head clamp then allowed definition of the limits of the tumour and subsequent planning of the incision and craniotomy. The patient’s head was prepped and draped in a sterile fashion, ensuring that he remained comfortable. The drapes were secured onto poles to prevent obscuring of the patient’s line of sight and communication with the anaesthetist.
A linear scalp incision was made, and craniotomy tailored to the exact tumour location. Neuronavigation was utilised to help define the limits of the craniotomy and confirm the tumour location intraoperatively. Further infiltration of the dura with local anaesthetic was done. Cranial ultrasound was also used as an adjunct to the neuronavigation to provide real-time assessment of tumour location.
Once this was confirmed, a durotomy was performed and both the tumour and eloquent cortex exposed. The next step of the procedure involved cortical mapping (Figure 2). This aided in location of a safe entry zone, as well as in defining the limits to which resection could be taken. Cold/iced saline solution was made available during this time, in case of provoked seizures. However, by avoiding stimulation of the same area consecutively, we avoided this.
A member of the neurosurgical team then performed the intraoperative neurological assessment, asking the patient specific questions. These questions were done as part of the baseline preoperative assessment and the patient’s answers were recorded. The same team member did the preoperative assessment, to ensure standardization.
All his intraoperative answers were the same as his preoperative answers, which indicated no iatrogenic dysphasia. Specific motor actions of the arms and legs were performed throughout the procedure to identify any compromise of the motor cortex. Additionally, both motor-evoked potentials and free-running electromyography were performed throughout the case. There were no iatrogenic deficits created.
The intraoperative consult in the form of a frozen section was also deemed necessary to guide the degree to which gross total resection should be pursued (confirmation of LGG). The frozen section revealed a glioma with no high-grade features, and successful gross total resection was accomplished. Margins of one centimetre were achieved, with no violation of eloquent cortex. The patient remained fully awake during the entire procedure, with no sedation required at any point.
There were no intraoperative adverse events, and the patient was monitored in the high dependency unit for 12 hours and stepped down to the neurosurgical ward. He was discharged home on the second postoperative day and advised to avoid strenuous activity for six weeks.
He was successfully weaned off his anti-epileptics. Final histology revealed a Grade 2 astrocytoma, and based on his age, he was referred to oncology for their opinion on radiotherapy. At 1-year follow-up, he remains seizure-free, and MRI brain at this time has not shown any recurrence.
DISCUSSION
The definition of an awake craniotomy is a neurological surgery in which the patient is deliberately kept conscious during the procedure, whether for a particular segment or the entirety of it. The benefits of an awake craniotomy in the resection of gliomas in eloquent/critical areas of cortex have been well documented in recent literature. First utilised in the surgical treatment of epilepsy1, it comprises of stimulation of an awake patient and subsequent identification of language and sensorimotor regions. This enables the goal of gross total tumour resection, while reducing the likelihood of debilitating postoperative neurological deficits.2-4
Indications/Contraindications
Patient selection is of paramount importance. While many contraindications are relative, the most critical criterion to fulfil is patient understanding and cooperation. Emotionally labile or psychiatric patients, patients under the age of 10 years, comorbidities that may require anaesthesia (obesity, obstructive sleep apnoea), tumours situated within deep subcortical tracts, other difficult tumour locations and any other factors that complicate patient positioning are typically contraindications to an AC.2,5
Preoperative Evaluation
The most crucial aspect of a successful AC is proper patient selection. Not every patient will be a candidate for an AC, and the neurosurgeon and anaesthetist must extensively counsel the patient. The staff involved in surgery, the expected tasks that the patient needs to perform, the position of the patient, use of the pins and head clamp, and the surgical instruments and their sounds/effects should be declared to the patient. All risks and potential complications must be explained, and contingency plans to address these must be determined and agreed upon. The patient should be aware that discomfort may be experienced, with the potential need for conversion to general anaesthesia. In particular, the risk of and the methods needed to prevent them from becoming intractable must be understood.6
Anaesthesia and Positioning
Early AC involved the anaesthetic modality known as Asleep-Awake-Asleep. However, it has become more common to perform Awake-Awake-Awake anaesthesia nowadays. This requires comprehensive patient counselling and management of patient expectations allowing avoidance of general anaesthesia and its risks of airway obstruction, hemodynamic compromise, post-operative nausea and vomiting, etc. Additionally, any interference with the intraoperative cortical mapping that may attributed to anaesthetic agents is minimised.
The utilisation of local anaesthetic to perform a scalp block effectively anesthetises the scalp and leaves sufficient volume for use on the dura mater (where pain fibres are also present). A scalp block facilitates pin placement for rigid head fixation. Once the pinions are applied, registration of the neuronavigation system is commenced and confirmed.
Technique
The scalp incision and craniotomy site are confirmed and marked with use of neuronavigation. Upon removal of the bone flap, further infiltration of the dura mater with local anaesthesia is done and followed by durotomy. Dural tack up sutures are placed, and preparation made for cortical mapping.
Bipolar probe stimulation is utilised to identify a safe entry zone for corticectomy. In the case of frontal gliomas, the primary and supplementary motor areas are confirmed. Cold saline is made available in the event that seizures are provoked.7
A margin of 1cm from the mapped functional parenchyma is determined, and tumour debulking is commenced. This allows maximal resection which is associated with better overall survival and higher disease-free progression rates.8-10
Postoperative Care
Patients who undergo an AC for low grade gliomas typically have shorter postoperative stays and a lower risk of development of new postoperative deficits as compared to those who have surgery under general anaesthesia11. This was explained in a study comparing motor outcomes in patients undergoing AC versus general anaesthesia, and it was found that significantly higher stimulation was needed to identify the motor cortex in anaesthetized patients.12 The overall cost of an AC was also found to be substantially less (a difference of up to 10,000 USD) in one centre, when compared to conventional methods.1 This has significant implications in low-resource settings, where there are limitations on rehabilitation services.
Relevance to Local Setting
In Trinidad and Tobago, healthcare costs account for a significant portion of the country’s budget, and measures that improve efficiency without jeopardizing patient outcome are in high demand. Limitations of currently existing resources and what implications they have on the individual patient as well as society need to be considered.
Postoperatively, brain tumour patients require admission to an ICU and possibly ventilation. Elective brain tumour surgeries are sometimes postponed when ICU beds, which are limited in number, are unavailable. Awake craniotomies can outmanoeuvre this challenge by allowing postoperative observation in an HDU style setting, or even in a dedicated neurosurgical ward. This drastically reduces the length of stay in an ICU/ventilation and its associated risks of pulmonary infections, tracheostomy, etc.
Additionally, overall length of stay in hospital is reduced. Postoperative deficits are reduced, and long-term rehabilitation/physiotherapy can be avoided. This is critical in our institution, as dedicated rehabilitation/step-down units are not available. AC can effectively liberate beds (both ICU and otherwise) for other patients. The cost to the hospital, and by extension the country, may be reduced by utilising AC for specifically indicated patients.
The major caveat is the specific equipment required for performance of an AC. Readily available neuronavigation and cortical mapping are key components and achieving this may be challenging due to the costs involved. While further cost-analysis needs to be done, it is likely that investing in this will provide long-term benefits, to both the patient and the country.
CONCLUSION
The myriad of benefits that an awake craniotomy offers is notable in patients with lesions near the eloquent cortex. The increase in tumour resection, while minimizing injury to the surrounding parenchyma, allows improved neurologic outcomes. This is particularly important in resection of low-grade gliomas, as it extends overall survival and prolongs disease-free progression.
Successful outcomes depend on adherence to certain steps and manoeuvres. Patient selection is perhaps the most critical of these, along with good communication and understanding between the patient, surgeon and anaesthetist. The possible complications and relevant strategies to address them must not be ignored, and the goal of a safe surgery and good patient outcome cannot be overstated.
Consideration should be given to the potential reduction in cost, hospital stay and improved patient outcome of awake craniotomies for low-grade gliomas, especially in a low-resource setting.
Ethical approval statement: Not applicable
Conflict of interest statement: None declared
Informed consent statement: Informed consent was given to us by the patient, for use of his images and writing of this case report.
Funding statement: Not applicable
Authors Contribution: All 3 authors were involved in the performance of the craniotomy. The conception of the manuscript was done by Drs Knight and Ramnarine, and the drafting/editing and revision by all 3 authors.
REFERENCES
- July J, Manninen P, Lai J, Yao Z, Bernstein M. The history of awake craniotomy for brain tumour and its spread into Asia. Surg Neurol. 2009 May;71(5):621-4; discussion 624-5. doi: 10.1016/j.surneu.2007.12.022. Epub 2008 May 2. PMID: 18452979.
- Hervey-Jumper, S. L., Li, J., Lau, D., Molinaro, A. M., Perry, D. W., Meng, L., and Berger, M. S. (2015). Awake craniotomy to maximize glioma resection: methods and technical nuances over a 27-year period. Journal of Neurosurgery JNS 123, 2, 325-339, available from: <https://doi.org/10.3171/2014.10.JNS141520> [Accessed 26 January 2021]
- Roni Zelitzki, MD, Akiva Korn, MMedSc, D-ABNM, Eti Arial, Carmit Ben-Harosh, MA, Zvi Ram, MD, Rachel Grossman, MD, Comparison of Motor Outcome in Patients Undergoing Awake vs General Anesthesia Surgery for Brain Tumours Located Within or Adjacent to the Motor Pathways,Neurosurgery, Volume 85, Issue 3, September 2019, Pages E470–E476, https://doi.org/10.1093/neuros/nyz007
- Alessandro De Benedictis, MD, Sylvie Moritz-Gasser, ST, Hugues Duffau, MD, PhD, Awake Mapping Optimizes the Extent of Resection for Low-Grade Gliomas in Eloquent Areas, Neurosurgery, Volume 66, Issue 6, June 2010, Pages 1074–1084, https://doi.org/10.1227/01.NEU.0000369514.74284.78
- Ibrahim GM, Bernstein M. Awake craniotomy for supratentorial gliomas: why, when and how?. CNS Oncol. 2012;1(1):71-83. doi:10.2217/cns.12.1
- Erez Nossek, MD, Idit Matot, MD, Tal Shahar, MD, Ori Barzilai, MD, Yoni Rapoport, Tal Gonen, MA, Gal Sela, MA, Rachel Grossman, MD, Akiva Korn, MMedSc, D-ABNM, Daniel Hayat, MD, Zvi Ram, MD, Intraoperative Seizures During Awake Craniotomy: Incidence and Consequences: Analysis of 477 Patients, Neurosurgery, Volume 73, Issue 1, July 2013, Pages 135–140, https://doi.org/10.1227/01.neu.0000429847.91707.97
- Erez Nossek, MD, Idit Matot, MD, Tal Shahar, MD, Ori Barzilai, MD, Yoni Rapoport, Tal Gonen, MA, Gal Sela, MA, Rachel Grossman, MD, Akiva Korn, MMedSc, D-ABNM, Daniel Hayat, MD, Zvi Ram, MD, Intraoperative Seizures During Awake Craniotomy: Incidence and Consequences: Analysis of 477 Patients, Neurosurgery, Volume 73, Issue 1, July 2013, Pages 135–140,
- Herrick IA,, Craen RA, , Gelb AW, , McLachlan RS, , Girvin JP, & Parrent AG, : Propofol sedation during awake craniotomy for seizures: electrocorticographic and epileptogenic effects. Anesth Analg 84:1280–1284, 1997
- McGirt MJ, Chaichana KL, Attenello FJ, Weingart JD, Than K, Burger PC, Olivi A, Brem H, Quinoñes-Hinojosa A. Extent of surgical resection is independently associated with survival in patients with hemispheric infiltrating low-grade gliomas. Neurosurgery. 2008 Oct;63(4):700-7; author reply 707-8. doi: 10.1227/01.NEU.0000325729.41085.73. PMID: 18981880.
- Smith JS, Chang EF, Lamborn KR, Chang SM, Prados MD, Cha S, Tihan T, Vandenberg S, McDermott MW, Berger MS. Role of extent of resection in the long-term outcome of low-grade hemispheric gliomas. J Clin Oncol. 2008 Mar 10;26(8):1338-45. doi: 10.1200/JCO.2007.13.9337. PMID: 18323558.
- Oumar Sacko, MD, Valérie Lauwers-Cances, MD, David Brauge, MD, Musa Sesay, MD, Adam Brenner, MD, Franck-Emmanuel Roux, MD, PhD, Awake Craniotomy vs Surgery Under General Anesthesia for Resection of Supratentorial Lesions4,Neurosurgery, Volume 68, Issue 5, May 2011, Pages 1192–1199, https://doi.org/10.1227/NEU.0b013e31820c02a3
- Roni Zelitzki, MD, Akiva Korn, MMedSc, D-ABNM, Eti Arial, Carmit Ben-Harosh, MA, Zvi Ram, MD, Rachel Grossman, MD, Comparison of Motor Outcome in Patients Undergoing Awake vs General Anesthesia Surgery for Brain Tumours Located Within or Adjacent to the Motor Pathways,Neurosurgery, Volume 85, Issue 3, September 2019, Pages E470–E476, https://doi.org/10.1093/neuros/nyz007
- Chikezie I. Eseonu, MD, Jordina Rincon-Torroella, MD, Karim ReFaey, MD, Alfredo Quiñones-Hinojosa, MD, The Cost of Brain Surgery: Awake vs Asleep Craniotomy for Perirolandic Region Tumours, Neurosurgery, Volume 81, Issue 2, August 2017, Pages 307–314, https://doi.org/10.1093/neuros/nyx022
