Brain Tumor Surgery | Dr. Zhou Liang (Neurosurgery) | CMCS Shanghai

About Dr. Zhou Liang

Dr. Zhou Liang is Chief of Neurosurgery and Director of the Skull Base Surgery Centre at Huashan Hospital, Fudan University — one of China's foremost academic neurosurgical centres and a national reference institution for the treatment of complex brain tumours, cerebrovascular disease, and skull base lesions. He is widely regarded as one of China's leading skull base neurosurgeons, with particular expertise in petroclival meningiomas, cerebellopontine angle tumours, and complex cranial base reconstruction. Dr. Zhou pioneered the application of the keyhole concept in skull base surgery in China — combining limited bone removal with high-speed drilling, intraoperative neuronavigation, and multimodal neurophysiological monitoring to achieve maximal tumour resection while preserving cranial nerve function and brainstem integrity. His centre is a national reference site for diffusion tensor imaging (DTI)-guided surgical planning, intraoperative indocyanine green (ICG) angiography, and molecular profiling of meningiomas for recurrence risk stratification. Dr. Zhou maintains active research collaborations with leading international neurosurgical centres including Mayo Clinic and UCSF, and has published extensively in journals including Journal of Neurosurgery, Neurosurgery, and Acta Neurochirurgica. His practice integrates surgical precision, functional preservation, and translational research — reflecting the philosophy that the goal of skull base surgery is not simply tumour removal, but the restoration of the patient's neurological life.

Case Overview

Ms. Catherine Elliot, a 48-year-old British secondary school teacher, presented with a six-month history of progressive diplopia, right-sided facial numbness, and worsening gait instability. MRI demonstrated a 4.5 x 3.8 x 3.5 cm dumbbell-shaped mass centred at the petroclival junction and extending into the cerebellopontine angle (CPA), with homogeneous contrast enhancement, significant brainstem compression, and fourth ventricle deformity. CT angiography confirmed 180° encasement of the upper basilar artery by the tumour. Diffusion tensor imaging (DTI) showed posterior-medial displacement of the corticospinal tract without interruption. Neurological examination revealed right abducens nerve palsy (CN VI), right trigeminal hypoaesthesia in the V1–V2 distribution (CN V), left-sided limb weakness (MRC Grade IV), and positive cerebellar ataxia testing. Dr. Zhou Liang designed a navigation-guided microsurgical strategy via the right retrosigmoid approach with limited petrosectomy, supported by continuous intraoperative neurophysiological monitoring (BAEP, SEP, MEP, EMG) and intraoperative ICG angiography. Simpson Grade II resection was achieved — macroscopic total resection with coagulation of the dural attachment. Post-operatively, the patient experienced transient right abducens palsy that resolved substantially by three months. No new limb weakness, no CSF leak, and no facial nerve deficit occurred. At three-month follow-up, facial numbness had improved, diplopia had largely resolved through compensatory mechanisms, House-Brackmann facial nerve grade was I, and the patient had returned to teaching.

Patient Background

• Name / Nationality: Ms. Catherine Elliot (pseudonym) — British
• Age / Sex: 48-year-old female
• Occupation: Secondary school teacher — high cognitive and communicative demands; strong motivation for functional recovery
• Chief Complaint: Progressive diplopia (right lateral gaze limitation), right facial numbness, and gait instability for 6 months
• Symptom Progression: Diplopia onset at 6 months; right V1–V2 facial hypoaesthesia at 4 months; left limb weakness and balance impairment at 1 month — indicating progressive brainstem compression
• Past Medical History: No hypertension, diabetes, or prior neurological conditions
• Neurological Examination: Right abducens palsy (CN VI); right facial pain hypoaesthesia in V1–V2 distribution (CN V); left limb power MRC Grade IV; positive finger-nose and heel-shin ataxia testing
• Audiometry: Mild right-sided sensorineural hearing loss (pure tone average threshold 40 dB)

Imaging and Diagnosis

MRI Brain with Contrast

• Location and morphology: Dumbbell-shaped mass centred at the petroclival junction, extending into the right cerebellopontine angle — 4.5 x 3.8 x 3.5 cm
• Signal characteristics: T1 isointense; T2 mildly hyperintense; homogeneous avid contrast enhancement — consistent with meningioma
• Tumour base: Broad dural attachment at the petrous apex
• Brainstem: Significant pontine compression and displacement; fourth ventricle deformed and displaced
• Cranial nerve involvement: Abducens nerve (CN VI) displaced ventrally; trigeminal nerve (CN V) compressed at the root entry zone (REZ)

CT Angiography / MR Angiography

• Basilar artery: 180° encasement by tumour — critical surgical risk factor
• Vertebral arteries: Bilaterally balanced development; no dominant side dependency
• Perforating vessels: Multiple short basilar perforators identified in close proximity to the tumour capsule

Diffusion Tensor Imaging (DTI)

• Corticospinal tract (CST): Displaced postero-medially by tumour mass; tract continuity preserved — no interruption identified
• Surgical implication: Functional motor pathway intact; preservation feasible with careful dissection along the tumour capsule

Pre-operative Diagnosis

• Giant petroclival meningioma — WHO Grade I most likely; estimated Simpson Grade III resection target pre-operatively
• Cranial nerve involvement: CN V (trigeminal), CN VI (abducens) — symptomatic; CN VII, CN VIII — at risk
• Basilar artery encasement — highest surgical risk factor
• Brainstem compression with corticospinal tract displacement — left limb weakness

Clinical Decision Making

The petroclival region is among the most surgically demanding territories in neurosurgery. This tumour presented four simultaneous challenges: its deep location at the junction of the posterior fossa and the clivus, requiring a long surgical corridor through critical neurovascular structures; 180° basilar artery encasement, where any traction or thermal injury to the arterial wall risks catastrophic brainstem infarction; involvement of multiple cranial nerves (CN V, VI, VII, VIII) in close proximity to the tumour capsule; and a corticospinal tract already displaced by mass effect, where any additional surgical trauma could convert a Grade IV limb weakness to complete hemiplegia.

Dr. Zhou Liang's surgical strategy: The petroclival region is not a place where we operate by feel. Every millimetre matters. Before we open the skull, DTI has shown us exactly where the corticospinal tract is — displaced postero-medially, but intact. Neuronavigation will keep us oriented in three dimensions throughout the procedure. BAEP will be our early warning system at the basilar artery: if the waveform amplitude drops more than 50%, we stop immediately — that is the non-negotiable red line for brainstem protection. Our goal is not simply to remove this tumour. Our goal is to remove this tumour and return this woman to her classroom. Those are not the same operation if we sacrifice function for volume. Simpson Grade II — macroscopic total resection with dural coagulation — is achievable here. But only if we respect the basilar perforators, identify every cranial nerve before we touch the capsule, and use CUSA to decompress from the inside before we attempt any capsule dissection. Patience and anatomy. That is the operation.

Surgical Procedure

Phase 1 — Positioning, Navigation Registration, and Craniotomy

Position: Left lateral decubitus; head fixed in Mayfield clamp; neck slightly flexed and rotated left to optimise the retrosigmoid corridor
Neuronavigation: iGPS intraoperative navigation system registered to pre-operative MRI and DTI fusion dataset — real-time tumour boundary and corticospinal tract localisation throughout the procedure
Neurophysiological monitoring: Continuous bilateral BAEP, SEP, MEP, and free-running EMG (CN V, VII, X) established prior to incision and maintained throughout

A right retrosigmoid craniotomy was performed with limited petrosectomy using a high-speed drill — removing a targeted segment of the petrous bone to shorten the surgical corridor to the petroclival junction and reduce cerebellar retraction. The dura was opened in a curvilinear fashion; CSF was released from the cerebellopontine angle cistern, allowing the cerebellum to relax naturally without fixed retraction.

Dr. Zhou's operative note: The keyhole concept in skull base surgery is not about making a small opening for its own sake. It is about making the right opening — precisely positioned to give the shortest, most direct path to the lesion with the least collateral exposure. The limited petrosectomy adds 20 minutes of drilling time and saves the patient from the cerebellar retraction injury that a conventional large craniotomy would require. That trade is always worth making.

Phase 2 — Tumour Debulking (Internal Decompression)

Under high-magnification microscopy, the cerebellopontine angle was opened and the tumour identified. The petrosal vein (vein of Labbé) was carefully preserved; selective sacrifice was considered only if necessary for corridor access, and ultimately avoided in this case.

Internal debulking was performed using the CUSA (Cavitron Ultrasonic Surgical Aspirator) — systematically removing the tumour core in a piecemeal fashion to reduce tumour volume and capsule tension before any attempt at capsule dissection. Bipolar coagulation was used for haemostasis throughout, with careful attention to avoid thermal spread toward the brainstem surface and basilar perforating vessels.

Dr. Zhou's operative note: You never pull a petroclival meningioma. You empty it first. CUSA allows us to remove the tumour from the inside — reducing the mass, collapsing the capsule inward, and creating the working space we need to dissect the capsule away from the brainstem and cranial nerves without traction. Traction on a tumour adherent to the basilar artery is how brainstem infarctions happen. Internal decompression first. Always.

Phase 3 — Microsurgical Dissection and Cranial Nerve Preservation (Critical Phase)

Basilar artery dissection: The tumour capsule was found to be adherent to the basilar artery wall over a 180° arc. Under continuous BAEP and MEP monitoring, blunt microsurgical dissection was performed using a fine dissector — developing the arachnoid plane between the tumour capsule and the arterial adventitia. At no point did BAEP amplitude fall below the 50% threshold. ICG angiography was performed following arterial dissection, confirming preserved flow in the basilar artery and all identifiable perforating branches.

Abducens nerve (CN VI): The nerve was identified displaced ventrally by the tumour mass. A nerve stimulator probe was used to confirm CN VI identity and map its course through the tumour capsule. Dissection was performed strictly outside the tumour capsule — preserving nerve continuity throughout. Transient post-operative palsy was anticipated given the degree of displacement and accepted as a manageable outcome.

Trigeminal nerve (CN V): The trigeminal root entry zone (REZ) was compressed by the inferior tumour pole. Careful sharp and blunt dissection under high magnification released the REZ from tumour adhesion — preserving nerve continuity and fascicular architecture.

Facial and vestibulocochlear nerves (CN VII, VIII): Both nerves were identified at the internal auditory meatus and confirmed intact by continuous EMG and BAEP monitoring throughout the dissection. No deterioration in BAEP waveform morphology or amplitude was recorded.

Dr. Zhou's operative note: Every cranial nerve in the posterior fossa looks like a white strand under the microscope. The stimulator probe is not optional — it is how we know which white strand is CN VI and which is an arachnoid band. We stimulate before we cut. Every time. And when the BAEP tells us to stop, we stop. The monitor is not a suggestion. It is the operation speaking to us.

Phase 4 — Tumour Resection Completion and Skull Base Reconstruction

Following cranial nerve and vascular dissection, the remaining tumour capsule was resected in its entirety. The dural attachment at the petrous apex was coagulated with bipolar electrocautery — achieving Simpson Grade II resection (macroscopic total resection with dural coagulation, without dural excision).

Skull base reconstruction: The dura was closed in a watertight fashion using primary suture supplemented by a dural substitute patch. Mastoid air cells exposed during petrosectomy were sealed with bone wax and obliterated with autologous abdominal fat — eliminating the communication between the middle ear and the intracranial compartment and preventing post-operative CSF leak and retrograde meningitis. A lumbar drain was placed prophylactically for 48 hours post-operatively.

Post-operative Management and Follow-up

ICU and Early Recovery

• ICU monitoring: 24-hour intensive monitoring of consciousness, pupillary responses, vital signs, and limb power
• Neurological status on awakening: Fully conscious; left limb power MRC Grade IV (unchanged from pre-operative baseline); right abducens palsy present (anticipated)
• No new deficits: No facial nerve weakness; no new limb weakness; no hearing deterioration; no CSF leak

Post-operative Complications and Management

• Transient right abducens palsy: Diplopia worsened transiently post-operatively — managed with neuroprotective pharmacotherapy (methylcobalamin, mecobalamin) and early neuro-ophthalmological rehabilitation. Compensatory mechanisms established by 3 months
• CSF leak: None — watertight dural closure and mastoid obliteration protocol effective
• Infection: None

Post-operative Imaging

• MRI at 1 week: Complete tumour resection confirmed; brainstem decompression achieved; no haematoma; no infarction
• DTI at 1 week: Corticospinal tract continuity preserved; tract position normalising as brainstem decompression progresses

3-Month Follow-up Assessment

• Facial numbness: Substantially improved — V1–V2 hypoaesthesia partially resolved
• Diplopia: Largely resolved through compensatory ocular motor adaptation; right abducens function recovering
• Facial nerve: House-Brackmann Grade I — normal facial movement and tone
• Limb power: Left limb MRC Grade V — full recovery
• Gait and balance: Normal; returned to independent ambulation without assistance
• Functional status: Returned to full-time teaching
• Molecular pathology: WHO Grade I meningioma confirmed; NF2 mutation identified; TRAF7 wild-type — low recurrence risk profile; adjuvant radiotherapy not indicated; annual MRI surveillance planned

Extended Case: Recurrent Petroclival Meningioma Following Prior Subtotal Resection

Dr. Zhou Liang's expertise in petroclival surgery extends to the most challenging scenario in skull base neurosurgery: recurrent meningioma in a previously operated field, where scar tissue, distorted anatomy, and prior cranial nerve injury create compounding surgical risk. A 55-year-old Australian woman presented with recurrent petroclival meningioma five years after subtotal resection at another institution, with progressive CN VII palsy and new brainstem compression. Dr. Zhou performed re-do retrosigmoid craniotomy with intraoperative facial nerve mapping and continuous EMG monitoring — achieving Simpson Grade III resection (near-total, with a small capsule remnant adherent to the facial nerve preserved intentionally to protect CN VII function). Post-operatively, facial nerve function was maintained at House-Brackmann Grade II. The residual tumour was treated with stereotactic radiosurgery (Gamma Knife) at Huashan Hospital, achieving tumour control at 2-year follow-up. This case exemplifies the principle that in recurrent skull base meningioma, functional preservation supersedes volumetric completeness — and that the combination of surgical debulking and radiosurgical consolidation is the optimal strategy for tumour control without neurological sacrifice.

Expert Commentary — Dr. Zhou Liang

1. The Keyhole Philosophy: Precision Over Exposure

The history of skull base surgery is a history of progressively larger exposures — the assumption that more bone removal equals better access and better outcomes. That assumption is wrong. A larger craniotomy does not improve tumour resection; it increases cerebellar retraction injury, prolongs operative time, and expands the reconstruction challenge. The keyhole concept inverts this logic: we remove the minimum amount of bone necessary to achieve a direct, unobstructed corridor to the lesion, and we use that corridor with maximum precision. The retrosigmoid approach with limited petrosectomy gives us direct access to the petroclival junction through a 3–4 cm bone window. Combined with neuronavigation and high-magnification microscopy, that window is sufficient for complete resection of even a 4.5 cm tumour — if the surgeon's technique is precise enough to use it. The keyhole is not a limitation. It is a discipline.

2. Multimodal Monitoring: The Operation's Second Nervous System

Intraoperative neurophysiological monitoring in skull base surgery is not a safety net — it is an active decision-making tool. BAEP amplitude is our real-time indicator of brainstem auditory pathway integrity: a greater than 50% drop in amplitude is our absolute stop signal when dissecting near the basilar artery. MEP changes warn us of corticospinal tract compromise before any clinical deficit is apparent. Free-running EMG from the facial nerve tells us when our dissection is approaching CN VII — before we can see it. DTI fusion with neuronavigation shows us where the corticospinal tract is in three dimensions throughout the procedure. Together, these modalities create what I call the operation's second nervous system — a continuous stream of functional information that guides every surgical decision in real time. In petroclival surgery, operating without this information is not bold. It is uninformed.

3. CSF Leak Prevention: The Reconstruction Is Part of the Operation

Post-operative CSF leak is the most common serious complication of skull base surgery involving the posterior fossa and petrous bone. It is also almost entirely preventable. Our protocol at Huashan Hospital is non-negotiable: watertight primary dural closure supplemented by dural substitute; bone wax sealing of every exposed mastoid air cell; autologous fat obliteration of the mastoid cavity; and prophylactic lumbar drainage for 48 hours. This multi-layer reconstruction strategy eliminates the communication between the intracranial compartment and the middle ear — the anatomical pathway for both CSF leak and retrograde meningitis. In our series of petroclival meningioma resections, the CSF leak rate with this protocol is below 2%. The reconstruction is not the end of the operation. It is the part of the operation that determines whether the patient goes home well.

4. Molecular Profiling and the Future of Meningioma Management

Surgical resection is the foundation of meningioma treatment — but it is no longer the whole story. Molecular profiling of meningioma tissue has transformed our understanding of recurrence risk. NF2 mutations, TRAF7 mutations, AKT1 mutations, and TERT promoter mutations each carry distinct prognostic implications that cannot be predicted from histological grade alone. A WHO Grade I meningioma with an NF2 mutation and a high Ki-67 index may recur faster than a WHO Grade II tumour with a favourable molecular profile. We now perform routine next-generation sequencing on all resected meningioma specimens at Huashan Hospital — using the molecular profile to stratify surveillance intensity, guide adjuvant radiosurgery decisions, and identify patients who may benefit from emerging targeted therapies. This is the direction of meningioma management globally, and it is the research direction of our collaboration with Mayo Clinic and UCSF. Surgery removes the tumour. Molecular profiling tells us what the tumour will do next.

How CMCS Shanghai Coordinated This Case

China Medical Concierge Shanghai (CMCS) supported Ms. Elliot's care pathway from initial overseas inquiry through three-month post-operative follow-up and long-term surveillance planning. Our coordination included:

• Pre-arrival review of MRI, CT angiography, audiometry, and neurological examination records; specialist referral to Dr. Zhou Liang's skull base neurosurgery team at Huashan Hospital, Fudan University
• Arrangement of multimodal pre-operative imaging at Huashan Hospital: contrast-enhanced MRI with DTI tractography, CT angiography with 3D reconstruction, and functional MRI — with results reviewed by Dr. Zhou's team and integrated into the neuronavigation planning dataset prior to the patient's arrival in Shanghai
• Bilingual interpretation during the pre-operative consultation — including detailed explanation of the petroclival meningioma diagnosis, the retrosigmoid approach rationale, the keyhole petrosectomy technique, the role of intraoperative neurophysiological monitoring, the BAEP red-line protocol for basilar artery protection, and realistic functional outcomes including the anticipated transient abducens palsy
• Facilitation of the patient's informed surgical consent — ensuring Ms. Elliot fully understood the cranial nerve risks, the Simpson Grade II resection target, and the post-operative rehabilitation pathway before proceeding
• Surgical admission logistics: neurosurgical theatre scheduling, ICU reservation, anaesthesia pre-assessment coordination, and accommodation support for accompanying family in Shanghai
• On-site medical interpretation throughout the hospitalisation — including ICU daily updates, post-operative neurological assessment explanation, MRI results communication, and discharge planning
• Neuroprotective pharmacotherapy coordination: methylcobalamin and mecobalamin prescription guidance; physiotherapy and neuro-ophthalmological rehabilitation referral in Shanghai prior to return travel
• Molecular pathology coordination: NF2 sequencing and Ki-67 results translation; explanation of low recurrence risk profile and adjuvant radiotherapy decision (not indicated); annual MRI surveillance schedule established
• Three-month follow-up coordination: MRI scheduling, neurological assessment, House-Brackmann grading, and results communication to Ms. Elliot's neurologist in the United Kingdom
• Long-term surveillance planning: annual MRI protocol established; direct communication channel between Dr. Zhou's team and the UK neurology team for ongoing tumour surveillance and any recurrence management planning

For international patients facing giant petroclival meningiomas or other complex skull base tumours — particularly those who have been told that surgery carries unacceptable neurological risk, or who have experienced recurrence after prior subtotal resection — the combination of keyhole microsurgical precision, multimodal intraoperative monitoring, molecular tumour profiling, and integrated radiosurgical capability at Huashan Hospital represents a standard of skull base neurosurgical care that is genuinely at the international frontier. CMCS exists to connect patients with that expertise: ensuring every surgical option is evaluated, every risk is explained in their language, and every step from pre-operative imaging to long-term oncological surveillance is coordinated across borders with precision and care.

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.