About Dr. Wu Hao
Dr. Wu Hao is Chief of Otology at Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine — one of China's highest-volume cochlear implant centres and a national reference institution for complex inner ear surgery and skull base otology. He is a nationally recognised leader in cochlear implantation, chronic ear disease, and skull base surgery, with particular expertise in high-risk anatomical variants including inner ear malformations, aberrant facial nerve, and cerebrospinal fluid gusher management. Dr. Wu's practice is defined by the philosophy that no anatomical complexity should be an absolute barrier to hearing restoration — that with precise pre-operative imaging, intraoperative neural navigation, and real-time electrophysiological monitoring, cases previously considered inoperable can be safely and successfully implanted. His team at Shanghai Ninth Hospital has established one of China's most comprehensive cochlear implant programmes, integrating surgical precision, audiological programming, and multidisciplinary hearing-language-psychological rehabilitation into a unified care pathway.
Case Overview
Ms. Emma Fischer, a 24-year-old German postgraduate student based in Shanghai facing imminent interruption of her studies due to progressive hearing loss, presented with a ten-year history of bilateral progressive sensorineural hearing loss, left ear total deafness for two years, and inadequate benefit from right-ear hearing aids. She had a history of purulent meningitis at age two. Genetic testing confirmed SLC26A4 mutation — large vestibular aqueduct syndrome. High-resolution temporal bone CT revealed bilateral Mondini dysplasia (cochlea with 1.5 turns, fused middle and apical turns forming a cystic cavity) and a critical anatomical hazard: the right facial nerve vertical segment was anteriorly displaced, overlying the round window niche and obstructing the conventional surgical approach. MRI confirmed cochlear nerve presence. Dr. Wu Hao abandoned the standard facial recess-round window approach and designed an individualised strategy: neural navigation-guided identification of the anteroinferior quadrant of the round window membrane as a safe entry point avoiding the aberrant facial nerve, intraoperative facial nerve monitoring (IONM) and electrically evoked auditory brainstem response (EABR) throughout, and a controlled cerebrospinal fluid gusher management protocol. Operative time was 90 minutes; blood loss under 20 mL; facial nerve EMG remained below 100 μV throughout. A transient House-Brackmann Grade II facial paresis resolved completely at one week. At six months, CAP score improved from 0 to 5 (understanding conversational speech); the patient returned to university and participates normally in academic seminars.
Patient Background
- Name / Nationality: Ms. Emma Fischer (pseudonym) — German; postgraduate student based in Shanghai; studies at risk of interruption due to hearing loss
- Age / Sex: 24-year-old female
- Chief Complaint: Bilateral progressive hearing loss for 10 years; left ear total deafness for 2 years; right ear hearing aid benefit inadequate
- History: Purulent meningitis at age 2, inadequately treated; progressive hearing loss since childhood; recent tinnitus and vertigo
- Genetics: SLC26A4 gene mutation confirmed — large vestibular aqueduct syndrome (LVAS); autosomal recessive inheritance
- Family history: No family history of hereditary deafness — de novo or carrier parents
Audiological and Imaging Assessment
Audiological Evaluation
- Left ear pure tone audiometry: Profound sensorineural hearing loss (>95 dB HL); no response — total deafness
- Right ear pure tone audiometry: Severe sensorineural hearing loss (75 dB HL); speech discrimination score 30% (open-set sentences) — inadequate for academic participation
- Tympanometry: Bilateral Type A — no middle ear pathology
- Auditory brainstem response (ABR): No waveforms elicited bilaterally — confirming severe auditory pathway dysfunction
High-Resolution Temporal Bone CT — Critical Findings
- Bilateral Mondini dysplasia: Cochlear basal turn normally formed; middle and apical turns fused into a single cystic cavity — total cochlear length 1.5 turns instead of the normal 2.5 turns; enlarged vestibule; semicircular canal hypoplasia
- Aberrant facial nerve — the primary surgical hazard: Right facial nerve vertical segment anteriorly displaced, overlying the round window niche; tympanic segment dehiscent (exposed without bony covering). Standard round window approach would place the facial nerve directly in the surgical field — risk of complete facial nerve transection with conventional technique
- Large vestibular aqueduct: Bilateral enlarged endolymphatic duct — confirming SLC26A4-related pathology
Inner Ear MRI (CISS Sequence)
- Cochlear nerve present bilaterally but attenuated — confirming neural substrate for cochlear implant stimulation; excluding cochlear nerve aplasia (which would contraindicate implantation)
Dr. Wu's pre-operative assessment: The CT tells us two things that change everything about this operation. First, the Mondini dysplasia means the cochlea is a cystic space communicating with the subarachnoid space — when we open the round window, cerebrospinal fluid will gush out under pressure. We must be ready for that before we make the first cut. Second, the facial nerve is sitting directly over the round window. The standard approach is not available. We need to find the anteroinferior quadrant of the round window membrane — the only area not covered by the nerve — and enter there. This requires navigation and monitoring. Without them, this operation should not be attempted.
Clinical Decision Making
Three compounding risks defined the surgical strategy: Mondini dysplasia with a 30–50% probability of intraoperative CSF gusher — requiring a pre-planned containment and sealing protocol; an anteriorly displaced facial nerve overlying the round window — eliminating the standard surgical approach and requiring navigation-guided identification of an alternative entry point; and a post-lingual deaf patient with a long disease duration — where auditory cortex plasticity is time-limited and the implant must be placed without delay.
Dr. Wu Hao's individualised strategy: Mondini dysplasia with facial nerve displacement used to be a relative contraindication to cochlear implantation. It is not a contraindication. It is a technical challenge that requires a different plan. The facial nerve is not in the wrong place — it is in its place, and we need to find our place around it. The navigation system shows us exactly where the nerve is in three dimensions. The monitoring system tells us in real time if we are getting too close. Between the navigation and the monitoring, we have more information about the anatomy than any surgeon had twenty years ago. We use that information.
Operative Procedure
Phase 1 — Approach and Neural Navigation
Anaesthesia: General anaesthesia without muscle relaxants — neuromuscular blockade eliminated to allow continuous facial nerve electromyographic monitoring throughout the procedure.
Incision: Retroauricular C-shaped incision approximately 4 cm — minimally invasive access preserving skin flap vascularity.
Mastoid cortical work: Precise bone removal to expose the sinodural angle. Neural navigation probe used to confirm the exact three-dimensional position of the anteriorly displaced facial nerve vertical segment before any drilling in the facial recess region — establishing a safe working corridor that avoids the aberrant nerve.
Round window identification: Under operating microscope, the round window niche was carefully identified beneath the anteriorly displaced facial nerve. The nerve covered the superior and posterior aspects of the round window membrane; the anteroinferior quadrant — approximately 25% of the membrane area — was accessible without nerve retraction.
Dr. Wu's operative note: The navigation probe confirmed what the CT predicted: the facial nerve is sitting directly over the round window. But the anteroinferior quadrant is clear. That is our entry point. It is a small target — less than 1 millimetre of accessible membrane — but it is enough. We mark it, we confirm it with the monitoring, and we proceed.
Phase 2 — Round Window Entry and CSF Gusher Management
Round window membrane incision: Microincision (<1 mm) made in the anteroinferior quadrant of the round window membrane under high-magnification microscopy — avoiding all visible facial nerve fibres. Facial nerve EMG: no response throughout the incision.
CSF gusher — anticipated and managed: Immediately upon membrane incision, clear cerebrospinal fluid emerged under pressure — confirming the Mondini dysplasia-associated perilymph-CSF communication. This was anticipated and the management protocol was pre-activated.
Gusher control protocol: Suction used to control flow rate without complete occlusion — allowing controlled egress rather than attempting complete immediate sealing, which risks pressure build-up and electrode displacement. Gelatin sponge strips packed around the round window niche to absorb fluid and initiate clot formation. Once flow rate reduced to a slow seep, electrode insertion proceeded.
Dr. Wu's management note: The gusher is not the emergency. The emergency is mishandling the gusher. If you try to plug it completely before inserting the electrode, you create pressure that will dislodge the electrode when you release the plug. The correct approach is controlled drainage — let the fluid flow at a rate you can manage, insert the electrode while the flow is controlled, then seal around the electrode. The gelatin sponge absorbs the fluid and forms a clot that seals the entry point naturally. We have done this many times. The protocol works.
Phase 3 — Electrode Insertion and Electrophysiological Verification
Electrode selection: Medium-length electrode array (20–22 mm) — shorter than standard to avoid deep insertion into the cystic Mondini cavity, which would risk electrode entry into the CSF space or vestibule rather than the cochlear duct.
Electrode insertion: Slow, controlled insertion under continuous fluoroscopic guidance — confirming electrode position within the cochlear basal turn and avoiding the fused middle-apical cystic cavity.
Intraoperative EABR: Electrically evoked auditory brainstem response recorded immediately after electrode insertion — clear Wave V identified at acceptable threshold, confirming functional cochlear nerve stimulation and auditory pathway integrity.
Wound closure: Musculoperiosteal flap advanced over the round window region; watertight layered closure. External ear canal deliberately left unpacked — allowing observation for any post-operative CSF leakage through the natural drainage pathway.
Operative data: Total operative time 90 minutes; blood loss <20 mL; facial nerve EMG peak <100 μV throughout (safe range); EABR Wave V clearly present.
Post-operative Course and Rehabilitation
Immediate Post-operative Period
- Facial nerve: Transient House-Brackmann Grade II paresis (mild weakness, complete eye closure) — attributed to intraoperative retraction oedema, not nerve transection; managed with corticosteroids and neurotrophic agents; complete recovery at one week
- No meningitis, no wound infection, no persistent CSF leakage
- Imaging: Post-operative CT confirmed electrode position in cochlear basal turn; no electrode misplacement into vestibule or CSF space
Device Activation and Programming (1 Month)
- First activation: Patient immediately detected sound; unable to discriminate speech — expected for long-duration deafness with auditory cortex adaptation required
- Programming strategy: High-frequency emphasis with C-CLEAR noise reduction — exploiting the preserved basal turn function of the Mondini cochlea to maximise high-frequency speech cue delivery; critical for consonant discrimination and speech intelligibility in noise
Rehabilitation Outcomes (6 Months)
- Categories of Auditory Performance (CAP): Improved from Grade 0 (no awareness of environmental sounds) to Grade 5 (understanding of common phrases without lip-reading) — five-grade improvement
- Speech Intelligibility Rating (SIR): Improved from Grade 1 (unintelligible) to Grade 3 (intelligible to attentive listener) — two-grade improvement
- Academic function: Returned to university; participates in group seminars and one-to-one supervision sessions; thesis writing resumed
- Bimodal hearing: Right ear hearing aid continued alongside left cochlear implant — bimodal stimulation improves speech recognition in noise through bilateral auditory input
Expert Commentary — Dr. Wu Hao
1. Mondini Dysplasia: From Contraindication to Indication
Mondini dysplasia was historically considered a relative contraindication to cochlear implantation because of the high CSF gusher risk and the unpredictable electrode trajectory in a malformed cochlea. This classification reflected the limitations of the technology and technique available at the time — not the inherent impossibility of the procedure. With high-resolution CT and MRI providing precise pre-operative anatomical mapping, neural navigation confirming intraoperative anatomy in real time, and a standardised gusher management protocol, Mondini dysplasia is now a manageable surgical challenge rather than a barrier to implantation. The key is preparation: every step of the gusher management protocol must be planned and the materials prepared before the round window membrane is opened. Surprise is the enemy of safe surgery. In Mondini implantation, there are no surprises — only anticipated events and pre-planned responses.
2. Aberrant Facial Nerve: Navigation as the Standard of Care
The facial nerve is the most consequential structure in otological surgery. A transected facial nerve produces permanent ipsilateral facial paralysis — a devastating outcome that is entirely preventable with appropriate technique. In cases of facial nerve displacement, the conventional anatomical landmarks that guide standard cochlear implant surgery are unreliable. Neural navigation — using pre-operative CT data registered to the patient's intraoperative anatomy — provides real-time three-dimensional localisation of the nerve that no amount of surgical experience can replicate from anatomical landmarks alone. Intraoperative EMG monitoring provides a continuous electrophysiological safety signal: if the surgical instrument approaches the nerve, the EMG fires before the nerve is damaged. Navigation shows where the nerve is. Monitoring tells you when you are getting too close. Together, they make aberrant facial nerve surgery safe. Separately, neither is sufficient.
3. CSF Gusher Management: Controlled Drainage, Not Panic Plugging
The CSF gusher in Mondini dysplasia is a predictable event, not a surgical emergency. The error that converts a manageable gusher into a catastrophe is the instinct to plug it immediately and completely. Aggressive plugging before electrode insertion creates a pressure differential that will displace the electrode when the plug is released. The correct protocol is controlled drainage: allow the fluid to flow at a manageable rate, insert the electrode under controlled conditions, then seal around the electrode with absorbable material that allows natural clot formation. Post-operatively, the external ear canal must not be packed — packing prevents observation of any persistent leakage and creates a closed space that can become infected. The ear canal is the drainage pathway. Keep it open and watch it.
4. Hearing Rehabilitation: Surgery Is the Beginning, Not the End
Cochlear implantation restores the electrical signal to the auditory nerve. It does not restore hearing. Hearing — the ability to interpret, discriminate, and understand sound — is a cortical function that must be relearned through structured rehabilitation. For a post-lingual patient with ten years of progressive hearing loss, the auditory cortex has partially reorganised away from sound processing. Rehabilitation must systematically re-engage those cortical networks through graded auditory training, speech therapy, and psychological support. At Shanghai Ninth Hospital, our rehabilitation programme integrates audiologists, speech-language pathologists, and psychologists into a unified team that follows each patient from device activation through functional independence. The surgery takes 90 minutes. The rehabilitation takes 12 months. Both are essential.
How CMCS Shanghai Coordinated This Case
CMCS Shanghai supported Ms. Fischer from initial inquiry through six-month rehabilitation completion, including: pre-consultation review of external audiological reports, CT imaging, and hearing aid trial records; specialist referral to Dr. Wu Hao at Shanghai Ninth Hospital's Otology and Cochlear Implant Centre; bilingual interpretation throughout all consultations, audiological assessments, and surgical consent discussions; coordination of high-resolution temporal bone CT, MRI CISS sequence, and genetic testing for SLC26A4 mutation; real-time surgical updates to the patient's family in Germany; post-operative monitoring with daily bilingual updates during the admission; device activation and programming session coordination with bilingual audiologist support; six-month CAP and SIR assessment coordination with results translation; rehabilitation scheduling including auditory training, speech therapy, and psychological support; and long-term surveillance protocol with direct liaison between Dr. Wu's team and the patient's ENT specialist in Germany.
For international patients with hearing loss, inner ear malformations, or cochlear implant needs in Shanghai, Dr. Wu Hao's team at Shanghai Ninth Hospital represents otological expertise at the international frontier — combining precision surgery, electrophysiological monitoring, and comprehensive rehabilitation to restore not just hearing, but the ability to participate fully in academic, professional, and social life. CMCS ensures that expertise is accessible: in the patient's language, with overseas physicians informed at every step, from pre-operative imaging through long-term audiological follow-up.
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.
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