Functional Radiosurgery
Stereotactic radiosurgery applied to non-cancer neurologic conditions — targeting specific brain structures or cranial nerves to improve symptoms without an incision. Where functional neurosurgery meets precision radiation medicine.
Precision Targeting
Many focused radiation beams converge on a small anatomic target — no incision, no implant, no anesthesia in most cases.
Functional Indications
Trigeminal neuralgia, tremor, and select psychiatric or pain conditions — treating function, not tumors.
Permanent Lesion
Functional SRS creates an irreversible change — making careful patient selection and precise dose planning essential.
Radiosurgery Beyond Oncology
Stereotactic radiosurgery (SRS) is best known for treating brain tumors — but it also has an important role in functional indications: non-cancer conditions where the goal is symptom improvement by precisely altering a very small target in the brain or along a cranial nerve.
In functional SRS, the mechanism is different. Rather than controlling tumor growth, the radiation creates a focused biologic effect — for example, targeting a segment of the trigeminal nerve for facial pain, or a thalamic nucleus for tremor. The effect is delayed, developing over weeks to months, and relies entirely on anatomic targeting and careful dose planning.
Main Indications
Functional radiosurgery has established and emerging applications across pain, movement disorders, and psychiatric conditions.
Trigeminal Neuralgia
The best-established functional SRS indication. Focused radiation targets a segment of the trigeminal nerve root to reduce or eliminate the severe, lancinating facial pain that defines this condition. Widely offered and supported by decades of clinical experience.
Learn more about trigeminal neuralgia →Tremor (Radiosurgical Thalamotomy)
Radiosurgery targets the ventral intermediate nucleus (VIM) of the thalamus to create a lesion that reduces contralateral tremor. Considered when DBS or MR-guided focused ultrasound are not suitable, or when a patient prefers a non-incisional approach.
Learn more about essential tremor →Select Psychiatric & Pain Indications
Radiosurgical capsulotomy and other circuit-based targets are used in research protocols or highly selected contexts for treatment-resistant OCD, depression, and certain pain syndromes. These applications require specialized evaluation and multidisciplinary oversight.
Learn more about OCD neuromodulation →Candidacy for Functional Radiosurgery
Candidates are typically patients who:
Because functional SRS creates a permanent lesion, patient selection and counseling are critical.
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✓Have a clear diagnosis and have tried appropriate first-line therapies for their condition.
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✓Prefer a non-incisional approach or have medical factors (age, anticoagulation, comorbidities) that make open surgery less desirable.
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✓Understand that benefit may be delayed (weeks to months) and that risks exist, including sensory changes, edema, and delayed radiation effects.
The Treatment Process
Functional radiosurgery is outpatient. The procedure itself is typically completed in a single day — but the clinical effect unfolds over time.
Before
Imaging, diagnosis confirmation, and a planning discussion that compares SRS with other options — DBS, focused ultrasound, or percutaneous procedures — depending on your specific condition. This comparative counseling is central to informed decision-making.
During
Outpatient treatment. Stereotactic immobilization (frame or mask), high-resolution imaging for target localization, treatment planning, and delivery of focused radiation. Most patients go home the same day.
After
Symptom monitoring and follow-up imaging when indicated. Symptom improvement may be gradual — developing over weeks to months as the biologic effect matures. Your team will counsel you on the expected timeline for your specific indication.
Benefits and Risks
Key Benefits
- No incision — completely non-invasive treatment
- No implanted hardware — nothing left in the body
- Outpatient workflow — most patients go home the same day
- Option for patients who cannot safely undergo open surgery or who prefer a non-incisional approach
Important Considerations
- Delayed effect — symptom improvement takes weeks to months, not immediately
- Variable lesion size — biologic response to radiation is not identical across patients
- Cannot "test" targets physiologically the way DBS or MRgFUS can before committing
- Potential radiation injury to adjacent structures depending on anatomy
A Comprehensive, Balanced Treatment Approach
Functional radiosurgery sits at the intersection of two disciplines — functional neurosurgery and high-precision radiation medicine. Dual training in both fields enables a uniquely integrated approach to patient care.
Functional Neurosurgery
Deep understanding of the neuroanatomic targets, circuit-based rationale, and clinical phenotyping that determines whether SRS, DBS, or focused ultrasound is the best fit for each patient.
Radiation Oncology
Expertise in dose planning, radiation biology, and delivery optimization — the physics and biology that determine lesion quality, safety margins, and long-term tissue response.
The Integration
Combining both perspectives — procedural selection, target definition, dose planning, and follow-up strategy — means patients receive a balanced recommendation among robotic DBS, MRI-guided focused ultrasound, and radiosurgery when multiple reasonable options exist. No single modality is favored; the right tool is chosen for the right patient.