Epilepsy Surgery & DBS | Dr. Ding Yuchuan (Neurology) | CMCS Shanghai

About Dr. Ding Yuchuan

Dr. Ding Yuchuan is a Senior Neurologist at Huashan Hospital, Fudan University — one of China's foremost neurology centres and a national reference institution for epilepsy surgery evaluation, deep brain stimulation, and functional neurological disorders. He is recognised for his expertise in presurgical epilepsy workup, stereoelectroencephalography (SEEG), deep brain stimulation for drug-resistant epilepsy, and the multidisciplinary management of complex epilepsy syndromes in which the balance between seizure control and neurological preservation demands individualised decision-making. Dr. Ding's practice is defined by the philosophy that drug-resistant epilepsy is not a failure of medicine — it is a signal that the epileptic network has a structural or functional substrate that pharmacology cannot reach, and that the goal of the epilepsy team is to identify that substrate with precision, evaluate the risk of targeting it surgically, and select the intervention that offers the best ratio of seizure control to neurological preservation for that specific patient. His department at Huashan Hospital has established one of China's most comprehensive epilepsy surgery programmes, integrating long-term video-EEG monitoring, high-resolution epilepsy MRI, FDG-PET, neuropsychological assessment, SEEG, and neuromodulation into a unified presurgical evaluation and treatment pathway for patients with medically refractory epilepsy.

Case Overview

Mr. Daniel Fitzgerald (pseudonym), a 28-year-old Irish office worker based in Shanghai, presented with a 15-year history of drug-resistant focal epilepsy with secondary generalisation, seizing 3–4 times per week despite sequential trials of carbamazepine, sodium valproate, and lamotrigine. Long-term video-EEG captured seizure onset in the left frontotemporal region with rapid bilateral spread. High-resolution epilepsy MRI demonstrated left hippocampal sclerosis — volume reduction and T2 signal hyperintensity. FDG-PET showed focal hypometabolism in the left temporal lobe. Neuropsychological assessment identified mild recent memory impairment consistent with left hippocampal dysfunction. A multidisciplinary team led by Dr. Ding Yuchuan determined that while left temporal lobe resection offered the highest probability of seizure freedom, the risk of significant memory deficit in a 28-year-old with a dominant-hemisphere hippocampal lesion was unacceptable as a first intervention. Deep brain stimulation of the left anterior nucleus of the thalamus (ANT-DBS) was selected as a reversible, adjustable neuromodulation strategy. At six months post-implantation, seizure frequency had reduced from 3–4 per week to 1–2 per month; memory function was preserved and showed mild improvement; and QOLIE-31 quality of life scores improved significantly.

Patient Background

• Name / Nationality: Mr. Daniel Fitzgerald (pseudonym) — Irish; 28-year-old office worker based in Shanghai
• Age / Sex: 28-year-old male
• Chief Complaint: Recurrent episodes of loss of consciousness with limb convulsions for 15 years; worsening frequency for 2 years
• Seizure history: First seizure at age 13 — sudden loss of consciousness, upward eye deviation, oral automatisms, bilateral tonic-clonic convulsions lasting 3–5 minutes with spontaneous resolution; subsequent seizures 2–3 times per month; progressive pharmacological tolerance over 15 years; worsening to 3–4 seizures per week in the past two years
• Seizure semiology: Polymorphic — focal motor seizures (unilateral limb jerking, seconds to tens of seconds) and generalised tonic-clonic seizures; no consistent aura reported
• Antiepileptic drug history: Sequential and combination trials of carbamazepine, sodium valproate, and lamotrigine — initial partial response followed by progressive loss of efficacy; meets criteria for drug-resistant epilepsy (failure of two appropriately dosed and tolerated AED regimens)
• No identified precipitants: No history of head trauma, encephalitis, meningitis, febrile seizures, or family history of epilepsy
• Examination: Neurological examination normal interictally — consciousness, language, orientation, cranial nerves, motor function, sensation, and reflexes all within normal limits; no pathological reflexes; no meningism

Diagnostic Workup

Routine EEG

• Interictal findings: Generalised bilateral spike-and-wave and polyspike-and-wave discharges recorded on multiple occasions — suggesting generalised epileptiform activity but insufficient to localise the seizure onset zone

Long-Term Video-EEG (VEEG)

• Ictal recordings: Multiple seizures captured; ictal EEG demonstrated spike discharge onset in the left frontotemporal region with rapid bilateral hemispheric spread
• Seizure classification: Focal onset seizures with secondary bilateral tonic-clonic generalisation — consistent with a left frontotemporal seizure onset zone; not primary generalised epilepsy
• Clinical correlation: Ictal semiology correlated with left frontotemporal onset — contralateral motor features and post-ictal confusion pattern consistent with left hemisphere involvement

High-Resolution Epilepsy MRI

• Standard sequences: No structural abnormality identified on routine MRI sequences
• Epilepsy protocol sequences: Left hippocampal sclerosis confirmed — reduced hippocampal volume and T2/FLAIR signal hyperintensity; the most common structural substrate of drug-resistant temporal lobe epilepsy and the most reliably identified lesion on dedicated epilepsy MRI

FDG-PET

• Left temporal lobe: Focal reduction in glucose metabolism in the left temporal lobe — interictal hypometabolism is the PET signature of the epileptogenic zone; concordant with the MRI and VEEG localisation to the left temporal region
• Concordance: MRI, VEEG, and PET all pointing to the left temporal lobe — high-confidence localisation of the seizure onset zone without the need for invasive SEEG in this case

Neuropsychological Assessment

• Memory: Mild recent (episodic) memory impairment — consistent with left hippocampal dysfunction; verbal memory more affected than visuospatial memory, reflecting dominant hemisphere involvement
• Other cognitive domains: Language, attention, executive function, and processing speed within normal limits
• Functional implication: Pre-existing memory impairment from hippocampal sclerosis; left temporal resection carries a significant risk of further memory decline in a patient with dominant-hemisphere disease and pre-existing verbal memory deficit

Dr. Ding's pre-operative assessment: The localisation in this case is clear — MRI, PET, and video-EEG all point to the left hippocampus. In a right-handed patient, the left hippocampus is the dominant hemisphere structure for verbal memory. He already has a mild memory deficit from the sclerosis. If we resect the left hippocampus, we will almost certainly worsen that deficit — in a 28-year-old office worker whose livelihood depends on his cognitive function, that is not an acceptable first step. DBS of the anterior thalamic nucleus gives us a reversible, adjustable intervention that can reduce seizure frequency without touching the hippocampus. If it works well, we have achieved meaningful seizure control without the cognitive risk. If it does not work well enough, the resection option remains available — we have not closed any doors. That reversibility is the key advantage of DBS in this patient.

Multidisciplinary Team Discussion and Treatment Strategy

The MDT convened by Dr. Ding Yuchuan included neurology, neurosurgery, neurophysiology, and neuroimaging. The consensus was that the patient met criteria for drug-resistant epilepsy, that the seizure onset zone was localised to the left temporal lobe with high confidence, and that left temporal lobe resection — while offering the highest probability of seizure freedom — carried an unacceptable risk of significant verbal memory decline as a first intervention in a 28-year-old with dominant-hemisphere hippocampal sclerosis and pre-existing memory impairment.

DBS target selection: Left anterior nucleus of the thalamus (ANT) — the evidence-based DBS target for drug-resistant focal epilepsy, supported by the SANTE trial (Stimulation of the Anterior Nucleus of the Thalamus for Epilepsy), which demonstrated a median 40–75% reduction in seizure frequency with ANT-DBS. The ANT is a critical node in the Papez circuit — the limbic network that includes the hippocampus, mammillary bodies, and cingulate cortex — and modulation of ANT activity disrupts the propagation of seizure activity through this network without directly ablating or resecting any structure.

Reversibility and adjustability: DBS is fully reversible — the stimulator can be turned off, the parameters adjusted, or the device explanted if needed. This reversibility preserves the option of subsequent resective surgery if DBS proves insufficient. It also allows iterative optimisation of stimulation parameters over months to years as the clinical response evolves.

Initial stimulation parameters: Voltage 1.0 V, pulse width 90 μs, frequency 140 Hz — standard ANT-DBS starting parameters per SANTE trial protocol; to be titrated based on seizure response and tolerability.

Operative Procedure

Stereotactic DBS Electrode Implantation — Left Anterior Nucleus of the Thalamus

Pre-operative imaging: High-resolution stereotactic MRI with fiducial frame registration performed the morning of surgery. ANT target coordinates calculated using stereotactic planning software — the ANT is identified on coronal MRI as the anterior thalamic nucleus immediately posterior to the mammillothalamic tract. Target coordinates verified by two independent neuroimaging team members.

Anaesthesia and positioning: General anaesthesia; stereotactic head frame applied; patient positioned supine with head in the frame. Scalp preparation and draping.

Burr hole and electrode insertion: Small burr hole created at the planned entry point on the left side. DBS electrode (4-contact lead) advanced along the planned trajectory to the ANT target under continuous fluoroscopic guidance. Electrode depth confirmed by intraoperative neurophysiological recording — characteristic ANT neuronal firing pattern identified, confirming electrode position within the target nucleus.

Intraoperative neurophysiology: Microelectrode recording performed along the planned trajectory to map the neuronal activity profile and confirm entry into the ANT. Test stimulation performed — no adverse effects (no visual phenomena, no sensory disturbance, no motor activation) at therapeutic parameters, confirming safe electrode placement.

Lead anchoring and IPG implantation: DBS lead anchored to the skull at the burr hole. Extension cable tunnelled subcutaneously from the scalp to the left infraclavicular region. Implantable pulse generator (IPG) placed in a subcutaneous pocket below the left clavicle.

Post-operative verification: CT scan performed immediately post-operatively; electrode position confirmed within the left ANT; no intracranial haemorrhage; no pneumocephalus.

Operative data: Total operative time approximately 180 minutes; blood loss minimal; no intraoperative or immediate post-operative complications.

Dr. Ding's operative note: The anterior thalamic nucleus is a small target — approximately 6 to 8 millimetres in its largest dimension. The stereotactic accuracy required to place the electrode within the nucleus, rather than in the adjacent white matter or the internal capsule, is the technical challenge of ANT-DBS. We use frame-based stereotaxy rather than frameless neuronavigation for this target because the frame provides submillimetre accuracy that frameless systems cannot reliably achieve for deep targets. The microelectrode recording is the intraoperative confirmation — the ANT has a characteristic firing pattern that tells us we are in the right place before we commit to the final electrode position. In this patient, the recording was unambiguous. The test stimulation produced no side effects at therapeutic parameters. We were confident in the position before we anchored the lead.

Post-operative Management and Outcomes

Stimulation Initiation and Parameter Titration

• Week 1 post-implantation: Stimulation initiated at 1.0 V, 90 μs, 140 Hz; patient tolerated well with no stimulation-related adverse effects
• Months 1–3: Parameters gradually titrated upward based on seizure diary and tolerability; voltage increased to 2.0 V; no paraesthesia, mood change, or cognitive side effects reported
• Ongoing: Seizure diary maintained; AED regimen continued unchanged during the titration period to isolate the DBS effect

Seizure Frequency Outcomes

• Pre-DBS baseline: 3–4 seizures per week (approximately 14–16 per month)
• 3 months post-DBS: 1–2 seizures per week — approximately 50–60% reduction in seizure frequency
• 6 months post-DBS: 1–2 seizures per month — approximately 85–90% reduction in seizure frequency; seizure severity also reduced — fewer generalisations, shorter duration, faster recovery

Neuropsychological and Quality of Life Outcomes

• Memory function: Repeat neuropsychological assessment at 6 months — verbal memory scores stable to mildly improved compared to pre-DBS baseline; no deterioration attributable to DBS; improvement likely reflects reduced seizure-related hippocampal injury
• QOLIE-31 (Quality of Life in Epilepsy): Significant improvement in total score at 6 months — driven by reduced seizure worry, improved daily activity capacity, improved social functioning, and improved emotional wellbeing
• Occupational function: Patient returned to full-time office work; driving status under review per local regulations pending sustained seizure reduction
• No device complications: No intracranial haemorrhage, infection, lead migration, or IPG malfunction at 6-month follow-up

Expert Commentary — Dr. Ding Yuchuan

1. Defining Drug-Resistant Epilepsy: When to Stop Adjusting Medications and Start Evaluating for Surgery

Drug-resistant epilepsy is defined by the International League Against Epilepsy as the failure of two appropriately chosen, dosed, and tolerated antiepileptic drug regimens — whether as monotherapy or in combination — to achieve sustained seizure freedom. This definition is important because it sets a clear threshold for referral to a comprehensive epilepsy centre for surgical evaluation. The evidence is unambiguous: the probability of achieving seizure freedom with a third, fourth, or fifth AED after two have failed is less than 5%. Continuing to trial additional medications in a patient who meets the drug-resistance definition delays access to potentially curative or significantly palliative surgical treatment, during which time each seizure causes cumulative neuronal injury, cognitive decline, and quality of life impairment. In this patient, 15 years elapsed between the first seizure and the DBS implantation. The drug resistance was established within the first few years. The delay in surgical referral — common in patients who are managed in general neurology settings without access to a comprehensive epilepsy programme — represents 15 years of preventable seizure burden.

2. The Anterior Nucleus of the Thalamus: A Network Node, Not a Seizure Focus

The rationale for ANT-DBS in focal epilepsy is network-based rather than lesion-based. The anterior thalamic nucleus is a central node in the Papez circuit — the limbic network that connects the hippocampus, fornix, mammillary bodies, mammillothalamic tract, anterior thalamus, and cingulate cortex in a reverberating loop. Seizures arising in the hippocampus or temporal lobe propagate through this circuit to generate the bilateral spread and generalisation that characterises the most disabling seizure types. By delivering high-frequency electrical stimulation to the ANT, DBS modulates the excitability of this entire network — raising the threshold for seizure propagation through the Papez circuit without ablating any structure within it. This network modulation is why ANT-DBS is effective for temporal lobe epilepsy even when the electrode is not placed at the seizure onset zone itself. The SANTE trial demonstrated a median 40% seizure reduction at 3 months and 69% at 5 years with ANT-DBS — with a subset of patients achieving seizure freedom. In this patient, the 85–90% reduction at 6 months exceeds the median trial outcome, reflecting the favourable network architecture of temporal lobe epilepsy for ANT modulation.

3. Dominant Hemisphere Hippocampal Sclerosis: Why Reversibility Matters More Than Efficacy

Left temporal lobe resection for left hippocampal sclerosis in a right-handed patient achieves seizure freedom in approximately 60–70% of cases — the highest seizure-free rate of any epilepsy surgery procedure. But it does so at the cost of a clinically significant verbal memory decline in approximately 30–50% of patients with pre-existing dominant-hemisphere memory impairment. For a 28-year-old office worker whose professional function depends on verbal memory — reading, writing, communication, learning — a 30–50% risk of significant memory decline is not an acceptable first intervention when a reversible alternative exists. DBS does not offer the same seizure-free rate as resection — but it offers meaningful seizure reduction without the irreversible cognitive risk. The correct framing is not “DBS versus resection” but “DBS first, resection preserved”. If DBS achieves sufficient seizure control to restore quality of life and occupational function, the patient has avoided an irreversible cognitive risk. If DBS proves insufficient, resection remains available — and the patient makes that decision with full information about what DBS can and cannot achieve, rather than having the resection option foreclosed by an early surgical decision made without a reversible trial.

4. Optimising DBS Parameters: Why the First Setting Is Never the Final Setting

DBS is not a procedure — it is a treatment that begins with the procedure and continues through years of iterative parameter optimisation. The initial stimulation parameters — voltage, pulse width, frequency, and contact configuration — are starting points based on published trial protocols, not optimal settings for the individual patient. The optimal parameters for seizure control vary between patients based on the precise electrode position within the ANT, the individual network architecture of the epilepsy, and the patient's tolerability of stimulation-related side effects. Parameter optimisation requires systematic adjustment of one variable at a time, with seizure diary data collected over weeks between adjustments to assess the effect of each change. At Huashan Hospital, we use a structured optimisation protocol that typically requires 6–12 months of iterative adjustment before reaching a stable parameter set. The patient's seizure diary is the primary outcome measure — not the stimulation parameters themselves. The goal is the minimum effective stimulation that achieves the maximum seizure reduction with the minimum side effects. In this patient, the voltage was titrated from 1.0 V to 2.0 V over three months, achieving the 85–90% seizure reduction at six months. Further optimisation continues.

How CMCS Shanghai Coordinated This Case

CMCS Shanghai supported Mr. Fitzgerald and his family from initial presentation through six-month follow-up, including: urgent coordination of neurology consultation with Dr. Ding Yuchuan at Huashan Hospital, Fudan University with priority appointment scheduling given the high seizure frequency and functional impairment; bilingual review of all prior neurology records, AED prescription history, and previous EEG reports with clinical summary for the MDT; coordination of long-term video-EEG monitoring admission including bilingual explanation of the monitoring protocol, seizure diary initiation, and daily updates to the patient's family; coordination of high-resolution epilepsy MRI and FDG-PET with bilingual radiology report translation and localisation interpretation; neuropsychological assessment coordination with bilingual explanation of test results and their implications for surgical decision-making; bilingual interpretation throughout all MDT discussions involving neurology, neurosurgery, neurophysiology, and neuroimaging; pre-operative DBS coordination including stereotactic MRI scheduling, bilingual surgical consent support, and family communication during the operative period; post-operative CT verification coordination with bilingual results communication; IPG programming session interpretation at stimulation initiation one week post-operatively; seizure diary coordination and bilingual monthly check-ins during the parameter titration period with results communicated to Dr. Ding's team; parameter adjustment session interpretation at each outpatient visit; six-month neuropsychological reassessment coordination with bilingual results communication to the patient's neurologist in Ireland; QOLIE-31 quality of life assessment coordination and results interpretation; and establishment of a long-term DBS management protocol with annual parameter review, battery status monitoring, and direct liaison between Dr. Ding's team and the patient's neurologist overseas.

For international patients with drug-resistant epilepsy, functional neurological disorders, or complex neurological conditions requiring comprehensive presurgical evaluation or neuromodulation in Shanghai, Dr. Ding Yuchuan's team at Huashan Hospital, Fudan University represents neurology expertise at the international frontier — combining long-term video-EEG, high-resolution epilepsy MRI, FDG-PET, neuropsychological assessment, and ANT-DBS to achieve meaningful seizure reduction and quality of life restoration in patients for whom pharmacological treatment has failed. CMCS ensures that expertise is accessible: in the patient's language, with overseas neurologists and families informed at every step, from the first EEG assessment through long-term neuromodulation management.

This case report is de-identified and published for educational purposes. All clinical details have been anonymized in accordance with patient privacy standards. CMCS Shanghai is a medical concierge service and does not provide direct medical care.