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MRgFUS: Non-Invasive Neurosurgery — What It Means and Why It Matters at KIMS Hyderabad
The world's first non-invasive neurosurgical treatment — no incision, no implant, no anaesthesia, no radiation. FDA-approved for essential tremor and tremor-dominant Parkinson's disease. First in Telangana and Andhra Pradesh, at KIMS Neuroscience, Secunderabad, Hyderabad.
A Surgical Result Without Breaching the Skull
FDA-Approved Treatment for Essential Tremor and Tremor-Dominant Parkinson's Disease.
The concept of neurosurgery — operating on the brain — has always implied an open surgical procedure: cutting the scalp, opening the skull, and working within the brain with instruments. Even the most minimally invasive brain procedures (endoscopic surgery through the nose, stereotactic biopsy through a tiny burr hole) still involve penetrating the skull in some way. MR-guided Focused Ultrasound (MRgFUS) is the first treatment in the history of neurosurgery that achieves a surgical result — creating a precise, therapeutic lesion within the brain — without breaching the skin, the skull, or the brain in any way. The skin is intact. The skull is intact. The brain is intact, except for the tiny target lesion that stops the tremor. Nothing is implanted. No anaesthesia is given. The patient walks out the same day.
For patients who have spent years, sometimes decades, with a debilitating tremor that medications cannot control, and who have been told that the only remaining option is deep brain stimulation (DBS) — a surgical procedure they may fear, or may not be fit for — MRgFUS is a genuinely transformative alternative. At KIMS, the first centre in Telangana and Andhra Pradesh to offer MRgFUS, this technology is available to patients across South India who previously had to travel to Delhi, Mumbai, or abroad.
Book a Consultation
Same-day MRgFUS eligibility assessment at KIMS — the first centre in Telangana and AP to offer this treatment.
040-44885000Emergency line: 040-46324365A Surgical Result, Without a Surgery
Non-invasive neurosurgery is a treatment that achieves a surgical result — the precise ablation or modification of a brain target — without any incision in the skin or skull, without any instrument entering the brain, and without any device being implanted in the body. MRgFUS is the world's first and currently the only truly non-invasive neurosurgical treatment approved for clinical use in tremor disorders.
- The gap MRgFUS fills — between medication failure and DBS
- For essential tremor, propranolol and primidone are effective for approximately 50–60% of patients. In the 40–50% where tremor persists despite optimal medical therapy, the alternatives were limited to accepting the disability or proceeding to deep brain stimulation (DBS) — a surgical procedure that drills into the skull, implants electrodes under general anaesthesia, and leaves an implantable pulse generator (IPG) requiring periodic programming and battery replacement every 5–7 years (non-rechargeable IPG). For patients who decline or are not fit for DBS, MRgFUS is the alternative that was previously unavailable in South India.
- The Vim thalamotomy — what is actually done in the brain
- The target is the ventral intermediate (Vim) nucleus of the thalamus — a small relay nucleus in the tremor circuit (the cerebellar-thalamo-cortical loop) whose abnormal oscillatory activity drives the tremor. A 4–6 mm thermal lesion in the Vim nucleus disrupts this circuit, stopping the tremor signal before it reaches the motor cortex. It is the same target as surgical thalamotomy (performed since the 1950s) and as the DBS electrode in thalamic DBS — but MRgFUS achieves the same endpoint without any instrument entering the brain.
- Unilateral only — why bilateral thalamotomy is not performed
- MRgFUS is performed on one side only (a thalamotomy contralateral to the dominant tremor hand). Bilateral thalamotomy carries a significantly elevated risk of dysarthria (speech impairment) and dysphagia (swallowing difficulty) from bilateral disruption of thalamocortical circuits. For patients with bilateral tremor where both hands are significantly affected, bilateral DBS remains the preferred option because it can be programmed to manage both sides with individualisable settings.
- NEJM-level evidence — the clinical trial foundation
- The pivotal FDA registration trial (Elias et al., NEJM 2016) was double-blind and randomised with a sham arm: the treated group showed 47% mean tremor improvement vs 0% sham at 3 months (p<0.001), and 75% mean tremor reduction at 12 months. The 5-year follow-up (Halpern et al., 2019) confirmed durable improvement in the majority of patients — placing MRgFUS among the best-evidenced neurosurgical procedures available.
- First in Telangana and AP — what this means for South India
- Before KIMS performed the first MRgFUS procedure in Telangana and Andhra Pradesh, patients from across South India had to travel to Delhi (AIIMS), Mumbai (Jaslok), or Chennai — or abroad. KIMS now brings this FDA-approved treatment within reach for the entire South Indian patient population, as well as patients from Karnataka, Odisha, and neighbouring states. A combined 2-day eligibility + treatment visit is available for patients travelling from outside the city.
The Non-Invasive Neurosurgery Stack
The six pillars of MRgFUS at KIMS — followed by the full clinical detail in the sections below.
Pillar 1: No Incision, No Implant, No Anaesthesia
The skin is intact. The skull is intact. The brain is intact, except for the tiny target lesion that stops the tremor. Nothing is implanted. No general anaesthesia is given. The patient walks out the same day.
Pillar 2: The Gap MRgFUS Fills
For the 40–50% of essential tremor patients whose tremor persists despite propranolol and primidone — and who decline or cannot tolerate DBS — MRgFUS is the missing surgical alternative.
Pillar 3: Vim Thalamotomy
A 4–6 mm thermal lesion in the ventral intermediate nucleus interrupts the cerebellar-thalamo-cortical tremor loop. Real-time MRI thermometry ensures precision throughout.
Pillar 4: Unilateral Only
MRgFUS treats one side (the contralateral hand) to avoid the increased dysarthria and swallowing risks of bilateral thalamotomy. Bilateral DBS remains the choice for patients with significant tremor on both sides.
Pillar 5: NEJM-Level Evidence
Double-blind randomised trial (Elias et al., NEJM 2016): 47% mean tremor reduction at 3 months in treated patients vs 0% in sham; 75% at 12 months; durable improvement at 5 years.
Pillar 6: First in Telangana/AP
KIMS is the first centre in Telangana and Andhra Pradesh to offer MRgFUS — bringing the treatment within reach for patients who previously had to travel to Delhi, Mumbai, or abroad.
The Problem MRgFUS Solves
Essential tremor — a life narrowed to the size of a safe activity
Essential tremor (ET) affects an estimated 5% of the global population over 60 — making it the most common movement disorder in the world, more common than Parkinson's disease. Despite its name, essential tremor is not “essential” to the person who has it. It is a relentless, action-triggered shaking of the hands, arms, head, or voice that is present during all voluntary movement: writing, eating with a spoon, pouring a glass of water, threading a needle, signing a document, using a phone. The tremor is worsened by stress, caffeine, and fatigue. It progressively narrows the activities that the person can perform independently and safely. Many patients stop eating in public. Many give up hobbies that require hand steadiness. Many lose careers. The social embarrassment of visible tremor is as disabling as the physical impairment itself.
The gap that MRgFUS fills — between medication failure and DBS surgery
For essential tremor, the first-line treatments are medications: propranolol (a beta-blocker) and primidone (an anticonvulsant). These are effective for approximately 50–60% of patients — but in the remainder, the tremor continues despite optimal medical therapy. Until MRgFUS, the only remaining surgical option was deep brain stimulation (DBS): drilling two holes in the skull, passing electrodes into the brain under stereotactic guidance, and implanting a pulse generator (a device the size of a matchbox) under the skin of the chest. DBS is effective, but it requires: general anaesthesia (a significant risk for elderly patients or those with cardiac or respiratory disease) · A hospital stay of several days · Post-operative programming sessions to optimise stimulation parameters · Battery replacement surgery every 5–7 years for non-rechargeable IPGs (rechargeable IPGs require regular charging) · Lifelong device management. For many patients — particularly those over 70, those with significant comorbidities, and those who simply do not want surgery — DBS is not an acceptable option. MRgFUS fills exactly this gap.
What MRgFUS Does to the Brain — The Thalamotomy
The thalamus and the tremor circuit
The thalamus is a paired deep brain structure that acts as the relay centre of the brain — routing sensory and motor information between the cortex and the rest of the nervous system. Within the thalamus, the ventral intermediate (Vim) nucleus is specifically involved in the cerebellar-thalamic-cortical loop that drives tremor in essential tremor and Parkinson's disease. When this loop fires abnormally — as it does in ET and PD — the result is the rhythmic, oscillatory muscle activation that produces tremor. The Vim nucleus is the surgical target for tremor control — the same target used in traditional thalamotomy (surgical lesioning of the Vim) and DBS (electrical stimulation of the Vim). MRgFUS achieves a thalamotomy — thermal ablation of the Vim — without opening the skull.
The Vim thalamotomy — why a lesion in one place stops tremor in the hand
The somatotopic organisation of the Vim nucleus means that a lesion in a specific part of the Vim interrupts the tremor circuit for the contralateral hand (the hand on the opposite side of the body). The target for right-hand tremor is the left Vim nucleus. A lesion approximately 4–6 mm in diameter at this location interrupts the abnormal cerebellar-thalamo-cortical oscillation, stopping the efferent tremor signal before it reaches the motor cortex. The lesion is small enough that surrounding thalamic structures — which relay sensation, vision, and other motor functions — receive minimal damage if the targeting is precise. MRI thermometry ensures precision in real time.
Why MRgFUS is performed on one side only (unilateral treatment)
MRgFUS creates a permanent lesion in the thalamus. For this reason, it is performed on one side only (unilateral thalamotomy) — treating the contralateral hand (typically the dominant hand, which is the most functionally important). Bilateral thalamotomy (creating lesions on both sides) carries significantly higher risk of side effects, particularly dysarthria (speech difficulty) and swallowing problems, because the bilateral Vim target areas are close to the speech and swallowing control pathways. In contrast, DBS can be safely used bilaterally because the stimulation can be adjusted: if side effects develop, the programming parameters are changed rather than the lesion being modified. Patients with bilateral tremor who are strongly motivated to treat both hands should discuss DBS with the KIMS team.
MRgFUS vs DBS — Choosing the Right Treatment
The comparison below summarises the differences between MRgFUS and deep brain stimulation across the major decision-making features used during patient counselling at KIMS.
Feature
MRgFUS
Deep Brain Stimulation (DBS)
What the procedure involves
Non-invasive focused ultrasound — no incision, no implanted device
A surgical procedure requiring implantation of electrodes into the brain and an implantable pulse generator (IPG/pacemaker) under the skin of the chest
Incision required
None
Yes — scalp + skull (burr holes) + chest (pulse generator)
General anaesthesia
Not required (local only for frame pins)
Required (or deep sedation)
Implanted device
None
Brain electrodes + implantable pulse generator (IPG/pacemaker) in the chest + connecting wire
Battery replacement
N/A
Every 5–7 years (non-rechargeable IPG), under general anaesthesia · Rechargeable IPGs last longer but require regular charging
Reversible?
No — the lesion is permanent
Yes — stimulation can be adjusted or turned off
Bilateral treatment
Not recommended (risk of speech/swallowing problems)
Yes — standard practice
Hospital stay
1 day (same day discharge for most)
3–5 days
Recovery time
1–3 days
1–2 weeks
Ongoing device management
None
Periodic clinical follow-up for programming + IPG replacement when the battery depletes
Eligibility constraint
Skull Density Ratio ≥0.4 required
No SDR requirement
Best for
Unilateral tremor · Elderly · High surgical risk · Surgery-averse patients
Bilateral tremor · Parkinson's with multiple motor features · Need for adjustability
The Clinical Case for MRgFUS as a First-Line Surgical Option
Evidence level: FDA-approved, NEJM-published RCT
MRgFUS is not an experimental treatment. It was evaluated in a double-blind, randomised controlled trial published in the New England Journal of Medicine (Elias et al., 2016) — the highest standard of clinical evidence. The trial enrolled 76 patients with medication-refractory essential tremor: 56 received MRgFUS thalamotomy and 20 received a sham procedure (the same frame and MRI, but no ultrasound energy delivered). At 3 months, 47% of treated patients had a significant clinical response versus 0% in the sham group. The mean tremor score improved by 47% in the treated group. At 12 months (open-label follow-up), tremor reduction averaged 75%. At 5 years (long-term follow-up data), a durable clinically meaningful improvement was maintained in the majority of patients.
Who benefits most — the ideal MRgFUS candidate
The patients who benefit most from MRgFUS are: (1) Patients with essential tremor as the primary diagnosis (not tremor from other causes) · (2) Patients in whom the dominant hand tremor is the most disabling feature · (3) Patients in whom medication has been tried and has failed to provide adequate control · (4) Patients with a skull density ratio of 0.4 or above · (5) Patients who prefer to avoid surgery and implanted devices · (6) Patients who are not fit for general anaesthesia · (7) Patients over 60 (who tolerate MRgFUS well and for whom DBS device management is burdensome).
What the Evidence Shows
MRgFUS at KIMS is grounded in NEJM-level randomised evidence and a clinically defined patient profile. The following points summarise the most clinically significant facts every patient and referring physician should know.
MRgFUS is the world's first and currently only truly non-invasive neurosurgical treatment approved for clinical use in tremor disorders — no incision, no implant, no anaesthesia
Essential tremor affects approximately 5% of the global population over 60 — more common than Parkinson's disease
Propranolol and primidone are effective for only 50–60% of ET patients — leaving the remainder dependent on surgical options
The Vim nucleus is the same target used by traditional thalamotomy and DBS — MRgFUS achieves the same anatomical lesion without breaching the skull
MRgFUS is unilateral only — bilateral thalamotomy increases dysarthria and swallowing-problem risk; bilateral DBS remains the standard for bilateral tremor
Elias et al., NEJM 2016: 47% mean tremor score improvement in treated patients at 3 months (vs 0% sham); 75% reduction at 12 months; durable at 5 years
MRgFUS lesion is permanent and not adjustable — tremor recurs in 10–20% of patients at 1–3 years; repeat MRgFUS is feasible but carries higher side-effect risk
KIMS is the first centre in Telangana and Andhra Pradesh to offer MRgFUS — eliminating Delhi/Mumbai/overseas travel for South India patients
MRgFUS Non-Invasive Neurosurgery at a Glance
| Fact | Details |
|---|---|
| What it achieves | Vim thalamotomy: 4–6 mm thermal lesion interrupting the cerebellar-thalamo-cortical tremor circuit · Tremor reduces or stops during the procedure · ~75% mean tremor reduction at 12 months (NEJM 2016) |
| Who qualifies | ET or PD tremor · Medication-refractory (failed ≥ 2 drugs) · SDR ≥ 0.4 · Dominant hand/arm tremor is the primary complaint |
| What is not possible | Cannot treat both hands (unilateral only) · MS tremor, cerebellar ataxia tremor, drug-induced tremor, dystonic tremor, psychogenic tremor not treatable · PD where bradykinesia and rigidity dominate → DBS preferred |
| Evidence level | NEJM 2016 double-blind RCT · 47% vs 0% sham at 3 months · 75% at 12 months · 5-year durable improvement (Halpern 2019) · PD tremor NEJM 2017 |
| vs DBS | MRgFUS: no implant, no surgery, non-adjustable, unilateral, same-day · DBS: bilateral possible, adjustable, requires surgery and battery replacement |
| South India access | First in Telangana and AP at KIMS · Previously: Delhi, Mumbai, or abroad · 2-day combined visit for out-of-Hyderabad patients · 040-44885000 |
| Emergency | 040-46324365 (24×7) for any acute neurological symptom |
Related Treatments
Explore related MRgFUS, DBS, and functional neurosurgery pages at KIMS Neuroscience:
Frequently Asked Questions
A Tremor That Has Outlasted Every Medication. An Operation You Cannot Have. — MRgFUS at KIMS Hyderabad.
A tremor that has outlasted every medication. An operation you cannot have because of your age or your heart. MRgFUS is the treatment that exists in the space between medication failure and surgery — and at KIMS Hyderabad, it is available today. First in Telangana and Andhra Pradesh. Call 040-44885000.
International enquiries: info@kimsneurosciences.com