Senior Director & HOD, Neurosurgery, Fortis Hospital, Noida
Part 4 of 9 in Diagnosis and Management of Brain Tumour
Awake Craniotomy and Neuronavigation for Tumours in the Brain's Eloquent Areas
September 6, 2026
Some brain tumours sit inside what neurosurgeons call eloquent areas: the motor cortex, on either side of the brain, or the speech centre, on the dominant hemisphere. A right-handed person is usually left-hemisphere dominant, though rarely the dominance sits on the same side as the writing hand, something that can be confirmed with selective angiography, though this is rarely needed in practice. Dr. Rahul Gupta walked his Jivo Healthcare audience through the two technologies that have made operating in these areas dramatically safer.
What neuronavigation changes
Before navigation, a stereotactic biopsy using a rigid Leksell frame faced real limits: the skull is a solid barrier, deep-seated lesions are hard to reach, vascular lesions can bleed during the procedure, a posterior fossa lesion cannot use the frame at all, and a lesion near the ventricles can shift once hydrocephalus is relieved. Neuronavigation solves most of this. It allows a frame-based or frameless biopsy, the latter especially useful in children, and can convert what would have been a simple burr-hole biopsy into a mini-craniotomy using the same instrument sets, at no added cost. The result is a smaller incision, a smaller or even absent cortical opening using a transsulcal approach, accurate localisation that avoids damaging surrounding brain, and near-total or total excision, including for lesions in the posterior fossa or cerebellum.
Operating on a patient who is talking to you
Awake craniotomy, combined with neuronavigation to localise the tumour, cuts post-operative deficits by close to 95 percent for tumours in eloquent regions. Under a scalp block rather than general anaesthesia, the patient can speak or move a limb on request while the tumour is being removed, giving the surgeon a live check on function rather than a post-operative surprise. It can be combined with neuromonitoring using grid electrodes for an added layer of mapping, and because the patient is never put under general anaesthesia, recovery is faster. The one real drawback: if the tumour bleeds heavily or a seizure occurs mid-procedure, the surgery has to convert to general anaesthesia.
Two cases from the operating table
A young woman with focal seizures in her hand had a motor-cortex tumour localised with a head frame and neuronavigation while fully awake, operated through the natural sulcus rather than a cut into the cortex. It turned out to be a grade 2 astrocytoma, and she had no resulting deficit. In a second case, a hyperintense lesion on the motor cortex was localised the same way; while the tumour was being removed, the patient moved her hand, then her leg and foot on request, confirming in real time that the pathways controlling movement were untouched.
This guide is based on a live Jivo Masterclass: Dr. Rahul Gupta taught doctors across Africa on February 9, 2025.
FROM THE LIVE Q&A
Moderator
In which type of brain tumour is the prognosis so poor that surgery, chemotherapy and radiotherapy offer no benefit?
Dr. Rahul Gupta
This applies mainly at the extremes of age: very large tumours in infants, or very large tumours in elderly patients involving critical areas of the brain. For brain stem and deep-seated thalamic gliomas presumed to be malignant, a biopsy may not even be taken, since these are treated directly with radiotherapy. Glioblastomas (grade 4 gliomas) carry a poor prognosis, though chemotherapy and radiotherapy can still extend survival and quality of life for that shorter span of time.
Frequently Asked Questions
How can post-operative complications be reduced in a resource-limited area?▼
Four things are essential. MRI is mandatory, brain tumour surgery should not be performed without it. An operating microscope is needed for magnification, even a basic one without fluorescence or navigation add-ons. The anaesthetist needs to be equipped and experienced in controlling brain swelling and blood pressure during surgery, ideally with a year or two of experience at a neuro centre. And a post-operative ICU with ventilator support is needed, since some patients require ventilation for a day or two. Good post-operative ICU care alone can reduce complications by 25 to 30 percent. With these four in place, superficial tumours such as meningiomas, surface gliomas and straightforward intraventricular tumours can be safely removed; difficult tumours should still be referred to a better-equipped centre.
What is the commonest brain tumour, and which type has the worst prognosis?▼
Metastasis used to be the most common brain tumour, but with better radiotherapy and chemotherapy most metastatic cases are now managed by radiation and medical oncology rather than surgery, except when a solitary large metastasis is causing a symptomatic mass effect. The tumours operated on most often today are gliomas and meningiomas. Gliomas run from grade 1 to grade 4, and grade 4 glioblastomas have the worst prognosis. Meningiomas usually have a good prognosis, though some are atypical or malignant and located at difficult skull-base sites near major vessels; those can be treated with modern radiotherapy such as gamma knife or cyberknife after a subtotal resection. Pituitary tumours are third most common and are usually benign, approached endoscopically through the nose.
After surgery, do all patients systematically need rehabilitation?▼
Yes. All patients need post-operative care from a team of physiotherapists and rehabilitative support. About 90 percent of patients who arrive without deficits leave hospital without one, but even they need psychological support, and patients with malignant tumours need considerably more of it given the chemotherapy and radiotherapy ahead. Patients need to see the neurosurgeon and physiotherapist regularly for at least 3 to 6 months, and continue lifelong follow-up MRIs.
What surgical technique is used for this kind of procedure?▼
The full presentation covered the range of techniques used, from neuronavigation and awake craniotomy to fluorescence-guided resection and endoscopic approaches, depending on the tumour's location and type.
Is a drain placed after surgery?▼
Yes, in around 80 percent of cases.
How much does awake craniotomy reduce post-operative neurological deficits?▼
By close to 95 percent, for tumours located in eloquent brain areas such as the motor cortex or speech centre, when combined with neuronavigation.
What happens if a patient bleeds heavily or seizes during an awake craniotomy?▼
The surgery is converted to general anaesthesia. This is the main drawback of the awake technique.
How does neuronavigation change a stereotactic biopsy?▼
It allows a frame-based or frameless biopsy, useful in children, and can convert a simple burr-hole biopsy into a mini-craniotomy using the same instruments, without added cost, while avoiding the limits of a rigid frame near the posterior fossa or a shifting ventricle.
In This Series: Diagnosis and Management of Brain Tumour
- 1.Diagnosis and Management of Brain Tumours
- 2.Recognising a Brain Tumour Early: Symptoms and Diagnostic Workup
- 3.The Principles Behind Every Brain Tumour Operation
- 4.Awake Craniotomy and Neuronavigation for Tumours in the Brain's Eloquent Areas
- 5.Fluorescence-Guided Surgery and Real-Time Imaging Inside the Operating Theatre
- 6.Reaching Pituitary and Vascular Brain Tumours Without a Wide Craniotomy
- 7.Brain Tumour Surgery in Children: Two Cases That Show What Changes
- 8.Recovery, Follow-Up and Prognosis After Brain Tumour Surgery
- 9.Delivering Safe Brain Tumour Surgery Where Resources Are Limited