CASE REPORT

Awake Craniotomy in Polyglot Patient with Intraoperative Multilingual Language Testing - Decision Making and Dilemmas

Luis Llamas
Luis Llamas, MD

Luis Llamas, MD
Moustafa Maita, DO (Chief Resident)
Maxim Eckmann, MD
Benjamin Wallisch, DO

Department of Anesthesiology,
University of Texas Health Science Center
San Antonio, Texas, USA

Alvin Sean Aqui, BS (4th Year Medical Student)
Department of Anesthesiology
UT Health San Antonio Joe R. and Teresa Lozano Long School of Medicine
San Antonio, Texas, USA

John Floyd, MD
Department of Neurosurgery,
University of Texas Health Science Center at
San Antonio, Texas, USA

Introduction
An awake craniotomy is a neurosurgical intervention utilized during the resection of lesions adjacent to eloquent brain areas. This technique requires a patient's cooperation in functional testing throughout intradural manipulation in order to preserve the language, speech, and motor functions. 

Before the advent of general anesthesia, archeological evidence shows the use of trepanation of the skull for seizure treatment. The modern era of awake craniotomies, performed with local anesthetic and intermittent sedation, began over sixty years ago when Dr. Wilder Penfield utilized electrical stimulation to map the cerebral cortex and remove epileptogenic foci.1-3 In 1996, Dr. Mitchel Berger expanded the utilization of intraoperative functional mapping to the excision of brain tumors.4

The indications for performing an awake craniotomy are split into four categories. The first category encompasses the resection of lesions near eloquent brain areas. The second includes procedures that require electrocorticographic mapping or electrophysiological recordings. Examples include deep brain stimulation in patients with Parkinson's disease or epilepsy surgery. The third refers to the obliteration of vascular lesions, such as arteriovenous malformations, that supply essential brain territories. Finally, the fourth category does not have a primary objective; it is utilized for minor intracranial procedures leading to faster recoveries and earlier discharges.5

Treatment
Patients must be largely free of sedation and cooperative during intradural manipulation. In this awake period, an Ojemann Cortical Stimulator is used to stimulate areas of the cerebral cortex while simultaneously testing the motor, speech, or sensory functions. Stimulated areas that cause a notable change from intraoperative and preoperative baseline are not resected.6 The anesthesia techniques utilized include:7

  • Asleep-awake-asleep (SAS): General anesthesia is used during the approach - skull fixation, craniotomy, and dural opening. Then anesthesia is stopped, the patient awakens, the airway is removed, and the patient participates in functional mapping. Upon completion of the intradural procedure, general anesthesia is resumed and continued until the final closing.
  • Awake-awake-awake (AAA) or Monitored Anesthesia Care (MAC): Sedation is applied during the approach and closure periods. During cortical mapping, sedation may be minimized or turned off completely.
  • Asleep-awake-awake (SAA): General anesthesia is utilized for the approach. Then the patients are awakened for mapping, and they remain so throughout until closure.

A meta-analysis8 that includes 47 studies of SAS and MAC reported no significant differences in awake craniotomy failure, intraoperative seizures, or novel neurological dysfunction dependent on the technique utilized. However, for conversion into general anesthesia, the odds ratio of SAS to MAC was 2.17 [95%CI: 1.22-3.85]. Overall, no technique has been proven superior; the selection is typically based upon institutional or clinician preference.

Case Description
A 30-year-old, 65 kilograms, ASA 3 right-handed female presented with adult-onset seizures during pregnancy.  Her workup revealed a large, greater than 5-centimeter non-enhancing left frontal opercular and insular mass consistent with an intrinsic brain neoplasm. The surgery was planned post-partum. Given the large size and presence of brain edema, functional MRI speech mapping was suboptimal for speech localization. Therefore, the decision was made to proceed with an awake craniotomy for resection of this large left-sided intracranial tumor, with Ojemann cortical stimulation to solicit speech arrest.

The patient is of Arabic descent who grew up in Germany. She is fluent in Arabic, German, and English. The patient consented to an awake craniotomy for tumor resection with intraoperative language mapping. The patient was prepared and thoroughly coached for an awake craniotomy.  It was emphasized to the patient that this technique was important to conserve as much cortical area responsible for intact speech as possible. Specifically, we consented to her for a SAS craniotomy. This technique was utilized to maximize patient comfort during the initial craniotomy approach. She agreed to proceed in this manner. Since the patient spoke the three languages, preparations were made to have an Arabic speaking anesthesiologist, a German-speaking neurophysiologist, along with an English-speaking neurosurgeon.

On physical exam, the patient was thin with a normal neck circumference, Mallampati class 1 airway, a thyromental distance greater than 5 cm, with intact dentition. After placing standard ASA monitors, the patient was preoxygenated with 100% oxygen, and anesthesia was induced with propofol. To minimize intraoperative sedation of the patient during the procedure, no benzodiazepine was used prior to induction of anesthesia. In addition, seeing that this patient was going to have conscious sedation for most of the case, an arterial catheter was not placed for her comfort during the awake segment. The patient was easy to mask ventilate without any airway adjuncts, and an LMA seated easily with good positive pressure ventilation. Subsequently, after LMA placement, the patient was positioned and placed in a semi-sitting position, and she continued to demonstrate adequate minute ventilation. To maintain spontaneous ventilation throughout the procedure, opioids were also omitted.

After confirming that all contact points were padded and checked, a bilateral local anesthetic scalp block was performed with 0.25% bupivacaine with epinephrine in an effort to maximize duration and minimize systemic absorption.9 Scalp infiltration was limited to <2.5 mg/kg of lean body weight. The surgeon then placed Mayfield pins, and we maintained the patient breathing spontaneously under inhaled sevoflurane. To mention a very important detail and teaching point, both the anesthesia team and the neurosurgeons were careful to set the patient in a comfortable sniffing position to ensure proper ventilation on extubation. An IV dexmedetomidine infusion10 was initiated in addition to our volatile agent for maintenance anesthesia. When the neurosurgeons were ready to commence resection of the mass, we removed the LMA under deep general anesthesia while the patient was ventilating spontaneously. The patient then gradually emerged from anesthesia and was awake and responsive enough to undergo language testing. The dexmedetomidine infusion11 was slowly tapered down while the patient was speaking. Throughout the duration of the surgery, benzodiazepines were not administered; however, spot doses of 25 μg of fentanyl were used to supplement the surgeon’s scalp block and assist with dissection.

The patient was awake and cooperative for language testing in English, German, and Arabic for the next several hours while the neurosurgeons meticulously resected nearly the entire tumor. During a certain portion of the surgery, the patient even spoke on the phone with her husband in all three languages. After completing the tumor resection and language testing, IV midazolam was given, and the dexmedetomidine infusion was reinitiated. The patient then fell asleep and was comfortable and breathing spontaneously. Since she was oxygenating and ventilating well while deeply sedated during this segment, we decided not to replace the LMA. Her surgical pathology report came back as WHO grade III anaplastic astrocytoma, IDH mutated.12 She has now completed adjuvant temodar chemotherapy with concurrent external beam radiation. She is 10 months out from surgery, with no evidence of residual disease. Her speech is normal, and she is enjoying seizure freedom.

Discussion

  • The case presented the following challenges:
  • Cortical mapping of a multilingual patient: Bello et al.13 concluded that intraoperative language mapping should encompass all languages that a patient is fluent in to conserve functionality. Therefore, healthcare providers who spoke English, German, and Arabic were present and participated in language mapping.
  • Airway management: An LMA was chosen because the patient had a reassuring airway exam, did not pose any serious aspiration risk, and posed decreased stimulation compared to an endotracheal tube during emergence.
  • Medication selection: We as clinicians must balance providing adequate analgesia while avoiding over-sedation that could potentially preclude effective functional mapping. Therefore, benzodiazepines were avoided preoperatively and throughout the length of the resection. General anesthesia was induced with propofol and maintained with a volatile anesthetic. Additionally, a dexmedetomidine infusion was titrated to effect during emergence and airway removal to preserve airway reflexes and prevent obstruction while providing patient comfort.

Awake craniotomy is an effective neurosurgical technique if used in the correct context. The Japan Awake Surgery Conference14 released guidelines concerning patient selection for awake craniotomy. The first is patients aged from 15 to 65 years. The underlying rationale is that patients within this age range will be able to follow commands and complete the tasks necessary for intraoperative functional testing. The second refers to intradural lesions that can be treated surgically, such as epilepsy or diffuse gliomas with indistinct borders between normal and diseased brain tissue. The third includes areas where surgical manipulation could worsen neurological function but can be evaluated via intraoperative testing. Cortical language areas are commonly involved, such as the lateral parietal lobe of the dominant hemisphere, Broca's area (Brodmann's area 44 and 45), or Wernicke's area (BA 22).

After identifying potential candidates, a physician should gain the trust and build rapport with the patient and discuss the rationale for pursuing an awake craniotomy. The discussion should encompass the chronology of the procedure, the necessary wakefulness and participation of the patient, benefits, potential complications, and alternatives. Patients who consent must still undergo further eligibility evaluations.15 Cognitive and language testing determines if patients have serious deficits that would inhibit their ability to participate and communicate during intraoperative testing effectively. Psychological and psychiatric evaluations identify a patient's capacity to remain calm, still and cooperate throughout the procedure.

Refusal of the patient is considered as an absolute contraindication for the awake craniotomy. Relative contraindications can be divided into four categories: neurological (dysphasia, altered mental status, dementia), psychiatric (claustrophobia), airway (obstructive sleep apnea, obesity, uncontrolled coughing), and tumor characteristics (highly vascular and large tumors).16 The underlying principle is that patients must be able to cooperate with intraoperative evaluations by having the ability to remain still, stamina to participate throughout the awake period, cognition for testing, and sufficient language capability to communicate changes and monitor speech faculty. For example, a successful awake craniotomy was performed on an elderly patient with a severe hearing impairment. A bone conduction voice amplifier was utilized during preoperative and intraoperative functional testing to facilitate communication, contributing to a better outcome.17

  • Potential complications and corresponding management strategies include the following:7,16,18
  • Seizures may occur during electrocortical stimulation. First-line treatment is the irrigation of the cortex with an icy crystalloid solution, followed by IV propofol in small boluses (30-50 mg). General anesthesia may be reinitiated for seizures lasting greater than five minutes.
  • Hypothermia and shivering are treated with blankets and warm saline infusions. Clonidine or tramadol have also been shown to be effective.
  • Delirium and agitation may occur upon emergence from general anesthesia for the awake phase. Although no consensus has been reached, a proposed strategy is to re-induce anesthesia with a propofol bolus (30-50 mg) and administer a dexmedetomidine bolus (0.1 to 0.2 μg/kg) prior to a subsequent awakening.
  • Pain is typically worse during pin fixation or dural traction. This can be treated with additional local anesthetic or IV acetaminophen.
  • Hypertension is commonly a result of anxiety, pain, or agitation; however, other etiologies must be considered. Treatment should be tailored to the underlying cause; esmolol or labetalol may be titrated.
  • Somnolence, inability to fully participate in functional mapping or hypoventilation may be caused by over sedation. Treat by terminating dexmedetomidine and propofol early and avoiding the use of long-acting opioids.
  • Nausea and vomiting may result from anxiety, surgical stimulation, and opioid use. A proposed prophylaxis strategy includes ondansetron 4 mg, dexamethasone 10 mg, and metoclopramide 10 mg.

Conclusion
To reiterate, an awake craniotomy is a neurosurgical technique that aims to maximize resection of brain lesions while minimizing the development of further neurological damage. This technique can be considered for patients who meet eligibility criteria, such as age, type, and site of brain lesions. After identifying potential candidates, physicians should build rapport with patients and discuss at length the rationale behind an awake craniotomy, sequence of the procedure, the required wakefulness and participation of the patient, benefits, potential complications, and alternatives. Patients who consent should undergo further cognitive, language, psychological, and psychiatric evaluations to determine their capacity to tolerate the procedure effectively. The only absolute contraindication is patient refusal. Several relative contraindications are based upon the precluding of purposeful intraoperative mapping, such as dysphasia, altered mental status, and claustrophobia. Potential complications of an awake craniotomy include seizures, agitation, hypothermia, nausea, vomiting, and pain.

References:

  1. Bulsara KR, Johnson J, Villavicencio AT. Improvements in brain tumor surgery: the modern history of awake craniotomies. Neurosurg Focus. 2005;18(4):e5.
  2. Penfield W, Boldrey E. Somatic motor and sensory representation in the cerebral cortex of man as studied by electrical stimulation. Brain. 1937;60:389-443.   
  3. Penfield W, Pasquet A. Combined regional and general anesthesia for craniotomy and cortical exploration. Part I. Neurosurgical considerations. Int Anesthesiol Clin. 1986;24:1-20.
  4. Berger MS. Minimalism through intraoperative functional mapping. Clin Neurosurg. 1996;43:324-337.
  5. Bonhomme V, Franssen C, Hans P. Awake craniotomy. Eur J Anaesthesiol 2009;26(11):906-912.
  6. Gonen T, Gazit T, Korn A, et al. Intra-operative Multisite Stimulation: Expanding methodology for cortical brain mapping of language functions. PLoS One. 12(7):e0180740 7/2017.
  7. Özlü O. Anaesthesiologist's Approach to Awake Craniotomy. Turk J Anaesthesiol Reanim. 2018;46(4):250-256.
  8. Stevanovic A, Rossaint R, Veldeman M, Bilotta F, Coburn M. Anaesthesia Management for Awake Craniotomy: Systematic Review and Meta-Analysis. PLoS One. 2016;11(5): e0156448
  9. Milian M, Tatagiba M, Feigl GC.  Patient response to awake craniotomy - a summary overview. Acta Neurochir (Wien). 2014;156(6):1063.
  10. Dziedzic T, Bernstein M.  Awake craniotomy for brain tumor: indications, technique and benefits. Expert Rev Neurother. 2014;14(12):1405.
  11. Bekker AY, Kaufman B, Samir H, Doyle W.  The use of dexmedetomidine infusion for awake craniotomy. Anesth Analg. 2001;92(5):1251.
  12. Louis DN, Ohgaki H, Wiestler OD, et al. The 207 WHO classification of tumours of the central nervous system. Acta Neuropathol. 2007; 114(2):97-109.
  13. Bello L, Acerbi F, Giussani C, et al. Intraoperative language localization in multilingual patients with gliomas. Neurosurgery. 2006;59(1):115-125.
  14. Kayama T; Guidelines committee of the Japan awake surgery conference. The guidelines for awake craniotomy guidelines committee of the Japan awake surgery conference. Neurol Med Chir (Tokyo). 2012;52(3):119-141.
  15. Santini B, Talacchi A, Casagrande F, et al. Eligibility criteria and psychological profiles in patient candidates for awake craniotomy: a pilot study. J Neurosurg Anesthesiol. 2012;24(3):209-216.
  16. Zhang K, Gelb AW. Awake craniotomy: indications, benefits, and techniques. Colombian J Anesthesiology. 2018;46(2S):46-51.
  17. Tachibana S, Omote M, Yamakage M. Successful awake craniotomy in an aged patient with a severe hearing impairment using a bone conduction voice amplifier: a case report. JA Clin Rep. 2019;5(1):37.
  18. Skucas AP, Artru AA. Anesthetic complications of awake craniotomies for epilepsy surgery. Anesth Analg. 2006;102(3):882-887.

Figure 1

Figure 1: Large non-enhancing left frontal opercular and insular mass lesion.

Figure 2

Figure 2: Intraoperative language testing.

Figure 3

Figure 3: Alvin Sean Aqui, BS (left) and Moustafa Maita, DO (right).

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