Awake craniotomy offers safe resection of brain tumours in eloquent area. Aga Khan University Hospital, Karachi, recently started the programme in Pakistan, and the current study was planned to assess our experience of the first 16 procedures. The retrospective study comprised all such procedures done from November 2015 to May 2016. Pre-operative and post-operative variables were analysed. Of the 16 patients, 11(68.75%) were males and 5(31.25%) were females. The overall median age was 37 years (interquartile range[IQR]: 23-62 years). The most common presenting complaint was seizures 8(50%), followed by headache6(38%). The common pathologies operated include oligodendroglioma and glioblastoma. Pre-operative mean Karnofsky Performance Status score was 76±10, which increased to 96±7 post-operatively at discharge. Besides, 2(12.5%) intra-operative complications were observed, i.e. seizure and brain oedema, in the series. The study had median operative time of 176 minutes (IQR: 115-352) and median length of stay of 4 days (IQR: 3-7).Awake craniotomy was highly effective in maintaining post-operative functionality of the patient following glioma resection. It was also associated with shorter hospital course and so lower cost of management.
Keywords: Awake craniotomy, Eloquent areas, Developing country, Postoperative deficits.
Awake craniotomy is a surgical technique performed under local anaesthesia so that brain tumours, especially those in eloquent area, are resected without giving patient any new neurological deficit. It has significant advantages over the primitive craniotomy under general anaesthesia which includes avoiding the risks of general anaesthesia, less intensive care unit (ICU) admissions, shorter operative time, shorter overall length of stay, reduced number of required arterial lines and catheters.1 The procedure plays a key role in modern neurosurgery in the developed world but its use in developing countries is still limited.1
Pakistan is a developing country which suffers significant economic burden due to surgical diseases, especially after brain tumour surgery. The economic burden is further worsened once patient develops functional dependability and inability to continue his employment and self-care.2
Developing the appropriate facilities for this technique was obviously not easy and required extensive training of the involved personnel. The current study was planned to report our initial experience of awake craniotomy cases.
Methods and Results
This retrospective case series was conducted at the Aga Khan University (AKUH), Karachi, and comprised all patients who had undergone awake craniotomy from November 2015 to May 2016. All these procedures had been done by a single neurosurgeon. Medical record files of the patients were reviewed. Data collected included demographics, pre- and post-operative symptomology, radiology, intra-operative time, new neurological deficit, histopathology and adjuvant treatment. All the data collected was kept confidential to preserve the anonymity of the patients. The data was analysed using SPSS 19.
A team compromising neurosurgeon and anaesthesiologists was sent to the United States where they received orientation for awake craniotomy. Thereafter, consensus on selection criteria for Pakistani population was developed and included patients with brain tumours, especially those in eloquent areas, low-grade gliomas, supratentorial elective tumour surgery, who were alert, oriented, willing for the procedure, and had adequate understanding of the procedure. All such patients were selected in the clinic. Magnetic resonance imaging (MRI) neuro-navigation, functional MRI and diffusion tractography were performed pre-operatively when required.
The anaesthetic technique mainly focussed towards the use \'awake throughout\' approach. The institution of scalp block was mainstay of the plan. In addition to routine pre-operative assessment, we arranged special sessions with patients to let them know about technique, its conduct and to respond any queries from patient\'s side. Anatomical block to supraorbital, auriculotemporal and greater occipital nerves was done bilaterally. Local infiltration was also done towards the pins side.
During the procedure, patients were put in the most neutral position possible using mayfield clamp, preferably supine or lateral, and covered in transparent drapes to document neurological exam. Cortical mapping was performed intra-operatively. Following scalp block, standard craniotomy using neuro-navigation was done. After craniotomy, dura was anesthetised by packing it with xylocaine-soaked patties. Standard durotomy was followed with excision of tumour while monitoring the neurological response. A neurosurgery resident would assess neurology concerned on frequent intervals, especially while working near eloquent cortex. Tumour resection was done until gross total resection without comprising any neurological function; if it was felt that patient\'s neurology was deteriorating the tumour, resection at that eloquent area would be stopped and residual tumour had to be left.
Post-operatively, a patient was neurologically assessed in recovery room and then in wards. MRI scan was done within 24 to 48 hours post-operatively. A majority of patients were shifted out of special care units within 24 hours post-operatively, with removal of invasive lines.
Of the 16 patients who underwent awake craniotomy, 11(68.75%) were males and 5(31.25%) females. The median age was 37 years (interquartile range [IQR]: 23-62). The pathologies observed were oligodendroglioma, glioblastoma (GBM), astrocytoma, central neurocytoma and metastasized breast cancer. Moreover, 5(31.25%) cases were recurrent in nature with history of previous craniotomy under general anaesthesia. Only 1(6.25%) case was metastatic, in which the patient had stage 4 breast cancer (Table-1)
Patients primarily presented with wide variety of symptoms, the most common being seizures 8(50%), followed by headache 6(38%). The mean Karnofsky Performance Status (KPS) score on admission was 76±10. Following awake craniotomy, the mean post-operative KPS improved significantly to 96±7, with 12(75%) patients having maximum KPS score on discharge. Only 2(12.5%) patients developed new neurological deficits, which included left homonymous hemianopia (case 7) and mild facial nerve weakness (case 4). The median operative time was 176 minutes (IQR: 115-352). The median length of stay for all patients was 4 days (IQR: 3-7) (Table-2)
In addition, 2(12.5%) intra-operative complications were observed in the study. Case 7 had intra-operative right occipital oedema which was managed with intracranial pressure (ICP) lowering manoeuvres which included mannitol and raising headside along with quick resection of tumour. Case12 had intra-operative seizure and was managed with midazolam. The seizures stopped thereafter so it was decided to continue with the awake procedure. This patient had another episode of seizure in recovery room which was managed with phenytoin.
Operating near an eloquent area for resection had been a huge challenge for neurosurgeons with regard to the post-operative functionality of the patient and the eventual quality of life. Awake craniotomy allows the surgeon to know when the patient starts to compromise any neurological function, so that the surgeon resects the lesion only to extend that the patient does not develop any new neurological deficit after the surgery. Hence, this technique has lower risk of compromising patient\'s quality of life after the surgery.3 Its efficacy to avoid post-operative neurological deficit further improves by the use of pre-operative functional imaging and tractography along with intra-operative brain mapping.4
In our study, the most common presentation was seizures, similar to a recent study conducted in Tehran.5 Patients in that study also significantly complained of speech disturbance and hemiparesis, but headache was uncommon, unlike in our case where headache was the second-most common complaint, followed by other symptoms.
The mean post-operative KPS improved significantly in our study, which defines the favourable outcome of this procedure. It is similar to the three-month post-operative mean KPS score of 93.7 in a study where 374 patients underwent awake craniotomy for intra-axial supratentorial cerebral lesion.6
We operated in adults only with median age of 37 years, while in another study surgery was done in a variety of cases ranging from a child aged below 10 years to a pregnant female.7 We operated most commonly for oligodendroma, both for low and high grade, followed by GBM, with all located supretentorially. In the developed countries, awake craniotomy is even used for infratentorial lesions or histopathology other than glioma, like meningioma.8
Two intra-operative complications were observed in our study, including intra-operative seizures and brain oedema. The complication of intra-operative seizures is well known in the literature, with an average of 9.5%.9 Literature also mentions respiratory distress, hypertension and tachycardia,3 which was not observed in our study.
The limitations of the current study included small number of cases, no control group for comparison, and the fact that all surgeries were performed at a single institution and by a single neurosurgeon.
Therefore, awakecraniotomy was found to be a highly effective procedure in improving functionality and quality of life post-operatively in patients with brain tumours, especially in an eloquent area.
Conflict of Interest: None.
1.Serletis D, Bernstein M. Prospective study of awake craniotomy used routinely and nonselectively for supratentorial tumors. J Neurosurg 2007; 107: 1-6.
2.Samad L, Jawed F, Sajun SZ, Arshad MH, Baig-Ansari N. Barriers to accessing surgical care: a cross-sectional survey conducted at a tertiary care hospital in Karachi, Pakistan. World J Surg 2013; 37: 2313-21.
3.Conte V, Baratta P, Tomaselli P, Songa V, Magni L, Stocchetti N. Awake neurosurgery: an update. Minerva anestesiologica 2008; 74: 289-92.
4.Sanai N, Mirzadeh Z, Berger MS. Functional outcome after language mapping for glioma resection. N Engl J Med 2008; 358: 18-27.
5.Alimohamadi M, Shirani M, Shariat-Moharreri R, Pour-Rashidi A, Ketabchi M, Khajavi M, et al. Application of awake craniotomy and intraoperative brain mapping for surgical resection of insular gliomas of the dominant hemisphere. World Neurosurg 2016; 92: 151-8.
6.Boetto J, Bertram L, Moulinie G, Herbet G, Moritz-Gasser S, Duffau H. Low Rate of Intraoperative Seizures During Awake Craniotomy in a Prospective Cohort with 374 Supratentorial Brain Lesions: Electrocorticography Is Not Mandatory. World Neurosurg 2015; 84: 1838-44.
7.Handlogten KS, Sharpe EE, Brost BC, Parney IF, Pasternak JJ. Dexmedetomidine and Mannitol for Awake Craniotomy in a Pregnant Patient. Anesth Analg 2015; 120: 1099-103.
8.deipolyi AR, Han SJ, Sughrue ME, Litt L, Parsa AT. Awake far lateral craniotomy for resection of foramen magnum meningioma in a patient with tenuous motor and somatosensory evoked potentials. J Clin Neurosc 2011; 18: 1254-6.
9.Szelényi A, Joksimovic B, Seifert V. Intraoperative risk of seizures associated with transient direct cortical stimulation in patients with symptomatic epilepsy. J Clin Neurophysiol 2007; 24: 39-43.
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