Rehabilitation Following Cochlear Implantation

1. The Cochlear Implant Team

• Surgeons - perform implantation and manage complications
• Audiologists - manage candidacy, device programming (mapping), and speech-perception monitoring
• Speech-language pathologists (SLPs) - drive auditory/verbal therapy and language development

• Educational specialists - assist with IEP planning, classroom accommodations, liaise with teachers
• Psychologists - assess cognitive ability, developmental disorders (e.g. autism), and family behaviors that affect outcomes
• Social workers - counsel families on expectations, facilitate support systems, improve clinic attendance
• Early interventionists and deaf/hard-of-hearing itinerant teachers - especially important for pre-surgical preparation and post-implant habilitation in children

2. Rehabilitation in Adults

Post-Activation Adjustment

• Postlingually deafened adults (most common): retained auditory memory aids in re-learning. Training focuses on complex listening skills - understanding speech in noise, telephone use, voice emotion recognition, and music perception.
• Prelingually deafened adults: auditory training and articulation training are both required, since the patient lacks an auditory template to reference.

Device Programming and Maintenance

• An audiologist specializing in CIs serves as the ongoing case manager
• Programming involves setting threshold levels, loudness balance, and dynamic range to create the patient's individual cochlear implant map
• Map changes are most frequent in the early weeks post-activation; objective measures (Neural Response Telemetry/NRT, Neural Response Imaging/NRI, electric acoustic reflex thresholds, audiograms) supplement behavioral programming when patient cooperation is limited
• Adult patients should be seen for reprogramming at least annually, with speech-perception scores tracked at each visit using validated protocols (e.g. MSTB - Minimum Speech Test Battery; HINT; CNC word lists; AzBio sentences)
• Sudden declines in performance should be documented with before/after speech scores to validate the patient's report and guide troubleshooting

Efficacy of Auditory Training in Adults

• Training improves the salience of spectral-temporal cues; the same sound can be perceived differently depending on prior experience
• Learning to interpret novel CI signals may take months to years before reaching maximum performance - analogous to how normal-hearing listeners learn initially unfamiliar sounds
• Studies show improvements are often attributable to cortical learning effects (improved labeling) rather than peripheral electrode discrimination
• A recent systematic review and meta-analysis found: patient-directed training significantly improved vowel-phoneme recognition and speech recognition in noise; clinician-directed training significantly improved sentence recognition in noise (both p < 0.001)
• 85% of CI audiologists surveyed recommend auditory training resources in the immediate post-activation period

3. Rehabilitation/Habilitation in Children

Why Early Intervention Matters

• The auditory system lays down neural structure for speech sound processing very early in life; these connections diminish rapidly without auditory stimulation
• Per Sharma et al., acoustic stimulation within the first 3 years of life allows the auditory cortex to develop comparably to a child with typical hearing
• Children implanted at younger ages demonstrate steeper rates of language acquisition and can catch up to hearing peers
• Development of audition does NOT occur automatically after implantation - active rehabilitation is required

Pre-surgical Referral

• Establish baseline auditory, language, and speech goals
• Begin enriching neural connections through auditory and linguistic experiences
• Prepare families for post-implant expectations

Post-implant Habilitation Program

• Close monitoring with regular speech and language assessments to track CI progress
• Therapists modify pre- and post-implant therapy continually based on outcomes
• Targets: listening skills, language development, and literacy
• Delivery can be home-based, center-based, or teletherapy depending on family needs

Predictors of Language Outcome in Children (Table from Cummings)

Modes of Communication

4. Children with Special Needs and Comorbidities

• Approximately 40% of children with SNHL have an additional disability
• CI is beneficial in children with comorbidities, though gains in speech intelligibility and auditory perception come more slowly
• Device non-use is higher in children with advanced developmental disabilities
• Earlier implantation is still preferred even in this group
• Rehabilitation programs must be adapted to the child's developmental profile (behavioral interventionists, OT/PT integration as needed)

5. Key Principles Across All Patients

1. Intensive, individualized therapy - Goals are unique to each patient and must be tailored regularly
2. Regular follow-up - At minimum annual reprogramming (adults); more frequent in children during the critical period
3. Family/caregiver involvement - Especially in pediatrics; parent-child interaction quality is independently predictive of outcomes
4. Performance monitoring - Standardized speech perception tests at each visit allow early detection of device issues and guide therapy focus
5. Realistic expectations - The CI is not a cure; "with intensive rehabilitation and regular follow-up, most deaf individuals are able to hear sounds and interact with the world in a way not possible with conventional amplification"

Recent Evidence (2023-2024)

Post-Stapedectomy Dizziness

Incidence

• Mild vertigo or dizziness occurs in approximately 1 in 20 (5%) cases after stapes surgery
• The reported incidence across studies varies widely - from 3.4% to 70% - reflecting differences in how vestibular symptoms are defined and assessed
• A small percentage (approximately 2.6%) may experience vertigo lasting longer than 12 months, representing permanent postoperative vestibular hypofunction
• Dizziness is less common with stapedotomy (small-fenestra technique) than with full stapedectomy due to reduced inner-ear trauma

Timing and Classification

Immediate / Early Postoperative (hours to days)

• Clinically: mild unsteadiness, positional vertigo, possible slight high-frequency threshold shift
• Typically resolves within days to weeks without specific treatment
• Also attributed to: perilymph loss from intraoperative suctioning, pressure changes in labyrinthine fluids, traumatization of the utricle, release of proteolytic enzymes, antigen-antibody reactions, and reduced blood supply to the labyrinth from a floating footplate during surgery

Subacute (1-6 weeks): Reparative Granuloma

• Mechanism: pyogenic inflammatory reaction, autoimmune or allergic response, or exuberant healing - sometimes attributed to the Gelfoam/fat graft seal or a foreign body reaction to the prosthesis
• Typical presentation: 7 to 15 days post-surgery with:
  • Initial hearing improvement followed by sudden or gradual SNHL
  • Vertigo
  • Reddish discoloration in the posterosuperior quadrant of the tympanic membrane
• Treatment: prompt recognition, systemic steroids, and surgical removal of the granuloma from around the oval window (laser-assisted preferred)

Delayed (weeks to months): Specific Causes

1. Perilymph Fistula (PLF)

• Historically more common with full stapedectomy using a Gelfoam patch; now rare with small-fenestra stapedotomy
• Features: mixed sensorineural-conductive hearing loss + vague unsteadiness; vertigo less common
• Symptoms may intensify with head movement, Valsalva manoeuvre, or even hiccupping, burping, yawning, or acoustic stimuli - reflecting pressure transmission through the fistula
• At revision surgery, PLF was confirmed in 4 of 10 suspected cases in one series
• Treatment: removal of prosthesis, tissue graft over the oval window, replacement with new prosthesis

2. Excessively Long Prosthesis

• An over-length prosthesis projects too deeply into the vestibule, directly contacting or irritating inner ear structures
• Features: dizziness and unsteadiness, often positional; exacerbated by pressure changes
• This is also a common finding at revision stapes surgery
• Management: revision surgery to replace with correctly sized prosthesis

3. Prosthesis Displacement / Malfunction

• Displaced or migrated prosthesis can irritate vestibular structures
• Often associated with incus resorption (resorptive osteitis of the long process of the incus) causing the prosthesis to migrate laterally and out of the fenestra

Prolonged / Persistent Vertigo

• Older age
• Prior stapes surgery in the contralateral ear (significant predictive factor for prolonged nystagmus)
• Poor seal around the prosthesis at the footplate
• Suboptimal postoperative hearing outcomes

Otosclerosis-Related Vestibular Dysfunction (Pre-existing)

• Endolymphatic hydrops
• Detachment of otoconia
• Degeneration of receptor cells
• Cupular deposits from the otosclerotic process encroaching on the cochlear endosteum

Summary of Causes by Timing

Management Principles

1. Mild early dizziness - reassurance, head elevation, vestibular sedatives if needed; almost always resolves spontaneously
2. Severe vertigo appearing days-weeks post-op - urgent audiogram + clinical review to exclude reparative granuloma, PLF, or prosthesis malposition
3. Reparative granuloma - steroids + surgical removal
4. PLF or long prosthesis - revision surgery; laser-assisted techniques (CO2 laser) are preferred for revision cases as they reduce mechanical trauma to the inner ear
5. Intractable vertigo - an indication for revision stapes exploration
6. Vestibular rehabilitation - may benefit patients with persistent disequilibrium after all correctable causes are excluded

Stapedotomy vs. Stapedectomy: Dizziness Risk

• Stapedotomy stabilizes the prosthesis in the center of the oval window
• Less mechanical trauma to inner ear structures
• Lower incidence of postoperative sensorineural loss and vestibular disturbance
• Comparisons show slightly better 4 kHz thresholds and lower high-frequency SNHL rates with stapedotomy, though overall speech discrimination outcomes are equivalent

Intranasal Corticosteroids (INCS)

Mechanism of Action

• Inhibit mediator release during both the early-phase (IgE-mediated, within minutes) and late-phase (4-8 hours) allergic reactions
• Suppress inflammatory cell influx - reduce the recruitment and activation of basophils, eosinophils, neutrophils, and mononuclear cells in nasal secretions
• Reduce TH2-type cytokines and overall inflammatory cell numbers within the nasal mucosa
• Decrease nasal hyperresponsiveness to subsequent antigen and histamine provocation
• At cellular level: bind glucocorticoid receptors in the cytoplasm → receptor-ligand complex translocates to the nucleus → upregulates anti-inflammatory genes (lipocortin-1, IkBα) and downregulates pro-inflammatory gene transcription (IL-4, IL-5, TNF-α)

Indications

Available Agents and Pharmacokinetics

Key Drugs

Systemic Absorption

• Ranges from <1% to up to 50% depending on the formulation
• Agents with greater first-pass hepatic metabolism (budesonide, fluticasone propionate, mometasone furoate) produce fewer systemic effects at equivalent doses
• Beclomethasone and ciclesonide are prodrugs - activated locally; ciclesonide has very low oral bioavailability
• Using formulations with lower systemic absorption is preferred; no difference in clinical efficacy between formulations has been demonstrated

Delivery Systems

Standard Delivery (Sprays and Drops)

• Aqueous sprays: most widely used; some patients experience anterior/posterior nasal drip sensation, which can reduce compliance
• HFA aerosol preparations (beclomethasone dipropionate HFA, ciclesonide HFA): approved for seasonal and perennial rhinitis ≥12 years; developed as an alternative for patients intolerant of aqueous sprays
• Drops: equally efficacious to sprays for CRSwNP; not studied in CRSsNP

Nonstandard Delivery (for CRS, especially post-ESS)

• Corticosteroid irrigations (most commonly budesonide in saline): takes advantage of the greater nasal penetration of high-volume irrigations. Post-ESS studies show significant improvements in symptom scores, quality of life, endoscopic scores, and polyp scores. One RCT showed irrigations were superior to sprays in post-ESS quality of life and symptom scores at 12 months. Systemic complication risk is low. Recommendation: especially post-ESS (Grade B)
• Mucosal atomized devices (MAD): deliver a fine mist; option in CRS (Grade B)
• Maxillary antrostomy sinus tubes (MAST): improve symptoms but ~35% complication rate (epistaxis, migration, infection); option only (Grade B)
• YAMIK sinus catheter with corticosteroids: no additional benefit over irrigation alone; not recommended

Dosing and Clinical Use

• Onset of efficacy: can begin within 1 day of dosing; maximum efficacy requires several days of regular use
• Prophylactic use in seasonal AR: ideally start 1 week before the pollen season
• Reassessment: review at 2 weeks - inspect nasal mucosa for irritation, assess therapeutic response
• Dose reduction: once symptomatic control is achieved, taper to the minimum effective dose
• Continuous vs. as-needed: continuous use is standard; however, as-needed intranasal fluticasone propionate has demonstrated superiority over placebo in some studies
• Correct technique: tilt the device away from the nasal septum (aim toward the ear on the same side), avoid sniffing forcefully after administration

Efficacy Highlights

• INCS control all nasal symptoms: sneezing, rhinorrhoea, nasal blockage, nasal itching
• Superior to H1 antihistamines for total nasal symptom scores and especially nasal congestion
• Superior to leukotriene receptor antagonists (LTRAs) in head-to-head comparisons
• Demonstrated efficacy for ocular symptoms in allergic rhinoconjunctivitis (likely through nasolacrimal reflex reduction)
• Combination INCS + intranasal antihistamine (e.g. azelastine + fluticasone): superior to either alone; the fixed-dose combination spray (Dymista) is particularly effective in moderate-to-severe AR and recommended by ARIA 2024-2025 guidelines
• In CRSwNP: >30 RCTs confirm improvements in symptom scores, endoscopic appearance, polyp scores, olfaction, nasal airway, and polyp recurrence rates

Side Effects

Local (common)

• Nasal irritation: ~10% of patients
• Epistaxis: 4-8% over weeks of use; higher over 1 year
• Nasal dryness, headache, throat dryness
• Septal perforation: rare, especially with poor technique (spraying toward the septum)
• Candida overgrowth in the nose: rare (unlike inhaled corticosteroids in the oropharynx)

Systemic (uncommon with appropriate formulations)

• Long-term use of newer INCS preparations is free of the systemic steroid concerns seen with oral corticosteroids
• No HPA axis suppression or growth retardation at standard doses with modern low-bioavailability agents
• However: pediatric patients on INCS should have height monitored every 3-6 months with a stadiometer, as a precautionary measure
• Biopsy at 1 year of continuous fluticasone propionate or mometasone furoate use: no mucosal atrophy found; normalization of pseudostratified ciliated columnar epithelium noted (suggesting disease-modifying effect)

Special Populations and Considerations

• NARES (non-allergic rhinitis with eosinophilia): INCS are the mainstay of treatment
• Weather-sensitive vasomotor rhinitis (IR): may respond poorly to INCS, reflecting a non-inflammatory neurogenic pathophysiology; intranasal antihistamine or anticholinergic may be more appropriate
• Rhinitis medicamentosa: INCS are used to facilitate decongestant withdrawal
• Pregnancy: aqueous formulations (particularly budesonide, which has the most safety data) are generally considered safe
• Children: growth monitoring mandatory; most modern INCS approved from age 2 (mometasone) or 6 years

Recent Evidence (ARIA 2024-2025)

ARIA-EAACI Guidelines 2024-2025: Allergic Rhinitis

What Is New in ARIA 2024-2025

1. GRADE framework throughout - all recommendations use the Evidence-to-Decision (EtD) framework with explicit directionality (for/against/neither) and strength (strong/conditional)
2. Multi-source evidence - beyond RCTs, the guidelines incorporate:
   • mHealth data (MASK-air app - real-world patient-reported outcomes)
   • Pharmacovigilance data
   • Expert cost surveys (to account for affordability and access in different regions)
   • Pragmatic trials and observational studies
3. AI-assisted question generation - artificial intelligence tools were used to analyse web searches on AR and help formulate guideline questions
4. Patient-centred perspective - shared decision-making is explicitly promoted
5. Within-class comparisons - for the first time, ARIA 2024-2025 compares individual agents within the same drug class (e.g., which INCS? which fixed combination?)
6. New guideline questions - several topics addressed for the first time, including INAH+INCS vs. no treatment, specific agent comparisons, and decongestants

Structure of the 2024-2025 Guidelines

Part I: Intranasal Treatment Recommendations

Key Recommendations

• "Suggest use of INAH+INCS over INCS" - particularly in patients with more severe symptoms
• This is a change from ARIA 2016, which placed INCS as the default first-line without a clear preference for combination
• Especially applies to patients for whom monotherapy is unlikely to provide significant improvement

• "In patients with AR in whom monotherapy is unlikely to lead to significant improvement in symptoms, we recommend using INAH+INCS over no treatment"
• Strong recommendation (moderate certainty for seasonal AR; very low certainty for perennial AR)

• Suggest INCS over INAH when monotherapy is chosen
• Reflects INCS superiority across all nasal symptom domains, especially congestion

• Among INCS agents, fluticasone furoate and fluticasone propionate appear to be the best options
• Conditional recommendation - flexibility based on patient preference is explicitly acknowledged

• Azelastine-fluticasone (AF) is recommended over olopatadine-mometasone (OM) for adult patients
• Based on network meta-analysis showing a 23% posterior probability of non-trivial improvement in nasal symptoms and 56% probability for ocular symptoms and RQLQ in favour of AF
• Conditional recommendation - some controversy exists about whether this margin justifies a directional preference (see debate below)
• Insufficient evidence to offer a preference between AF and OM specifically for perennial AR

• INCS preferred over decongestants for standard treatment
• Short-term decongestants (<5 days) may be used when INCS is being introduced to compensate for INCS's delayed onset - or alternatively INAH+INCS can be used for this purpose

What Changed vs. ARIA 2016 (Intranasal)

Part II: Oral and Ocular Treatment Recommendations

Key Recommendations

• Recommend INCS over OAH - confirming the established hierarchy
• INCS superior particularly for nasal congestion, which OAH do not adequately address

• Recommend OAH over LTRA
• This reflects concern about LTRA neuropsychiatric side effects (FDA black box warning on montelukast) and overall lower efficacy compared to antihistamines

• Suggest against adding LTRA to OAH - combination does not provide meaningful additional benefit over OAH alone and adds risk

• Suggest OAH over OcAH for patients with both nasal and ocular symptoms
• OAH provide systemic cover for both symptom domains; OcAH are limited to ocular symptoms

• Considerations for choosing among individual OAH agents are presented, accounting for sedation profiles, cost, and patient preference
• Second-generation OAH (cetirizine, levocetirizine, fexofenadine, loratadine, desloratadine) are preferred over first-generation agents

What Changed vs. ARIA 2016 (Oral/Ocular)

Overall Treatment Hierarchy (ARIA 2024-2025 Summary)

Most effective ──────────────────────────────────► Least effective
INAH+INCS  >  INCS  >  INAH  >  OAH  >  LTRA

• Fixed INAH+INCS combination (azelastine-fluticasone) sits at the top of the AR pharmacotherapy hierarchy
• INCS monotherapy remains first-line when combination is not available/affordable
• OAH are appropriate for mild/intermittent disease
• LTRA are now clearly de-prioritised and should not be added to OAH

Methodology Highlights

• GRADE EtD framework: 12 criteria evaluated for each question (effects, certainty, values, balance, resources, equity, acceptability, feasibility)
• Multi-source evidence integration: uniquely combines classical RCT data with real-world mHealth data from the MASK-air platform (patient-reported symptom and medication use logs from thousands of patients globally)
• Cost considerations: a global survey of ARIA experts on treatment costs was incorporated, facilitating adaptation to different healthcare settings
• Children and adolescents: each recommendation includes explicit applicability statements for paediatric populations
• All recommendations apply to both adults and children unless otherwise specified

Points of Ongoing Debate

• The network meta-analysis supporting it showed moderate NMA-based posterior probabilities (23% for nasal symptoms, 56% for ocular/QoL) - these are probabilistic outputs, not classical p-values
• Critics argue that persistent heterogeneity and network incoherence should have warranted downgrading the certainty of evidence from "moderate" to "low" per standard GRADE methodology
• Olopatadine-mometasone has a 52-week RCT in perennial AR showing long-term efficacy that the guidelines did not fully incorporate
• The guidelines themselves acknowledge these are conditional recommendations with wide scope for clinical flexibility based on patient values, local availability, and cost

Clinical Implications

1. For mild, seasonal AR: OAH remain appropriate and accessible
2. For moderate-severe or perennial AR: INCS is first-line; consider INAH+INCS combination
3. LTRA (montelukast) use should be minimised in AR - not to be added to OAH
4. Decongestants: only appropriate for short-term (<5 days) symptom relief; INCS or INAH+INCS preferred for anything beyond that
5. Affordability matters: guidelines explicitly state that treatment decisions must account for cost and access - a conditional recommendation leaves room to use more affordable alternatives where AF combination is not accessible
6. Immunotherapy: although not the focus of either Part I or II, ARIA continues to endorse allergen immunotherapy (subcutaneous and sublingual) as disease-modifying treatment in appropriate patients, which pharmacotherapy alone cannot achieve

Anterior Skull Base Approaches

Anatomy of the Anterior Skull Base

• Cribriform plate and crista galli - the olfactory nerves pass through the cribriform foramina; the lateral lamella is a thin bony partition between the cribriform and the ethmoid roof (fovea ethmoidalis)
• Keros classification - describes the vertical height of the lateral lamella (depth of cribriform relative to fovea ethmoidalis): Type 1 (1-3 mm, 23%), Type 2 (4-7 mm, 76%), Type 3 (8-16 mm, 1%); increasing depth raises the risk of dural injury during endonasal approaches
• Anterior and posterior ethmoid foramina - mark the frontoethmoid suture, a key guide to dural level; the posterior ethmoid foramen lies 4-7 mm anterior to the optic canal
• Planum sphenoidale - the flat superior surface of the sphenoid body connecting the cribriform to the sella
• Optic canal - transmits the optic nerve and ophthalmic artery

Classification of Surgical Approaches

• Purely extracranial (endonasal, transfacial)
• Combined intracranial + extracranial (craniofacial)
• Purely intracranial (craniotomy-based)
• Endoscopic endonasal (expanded endonasal approach - EEA)
• Minimally invasive / keyhole craniotomies

1. Classic Anterior Craniofacial Resection (CFR)

Indications

• Sinonasal malignancies extending to involve the cribriform plate and anterior cranial fossa
• Tumors where facial approaches alone cannot achieve adequate superior margins
• Esthesioneuroblastoma, sinonasal undifferentiated carcinoma, adenocarcinoma, SCC with skull base involvement

Operative Technique (Cummings)

1. Preoperative preparation: broad-spectrum antibiotics (sinonasal-intracranial connection); lumbar puncture for brain decompression and minimizing retraction
2. Incision: bicoronal incision from tragus to tragus (the most utilitarian approach for anterior skull base), with preauricular extensions; this preserves the anterior branches of the superficial temporal artery
3. Scalp flap elevation: anterior flap elevated in the subgaleal plane to preserve the pericranium for later reconstruction
4. Pericranial flap: incised broadly and elevated with its blood supply from the supraorbital and supratrochlear vessels; this provides the reconstructive flap for skull base closure
5. Frontal craniotomy: bur hole at midline, side-cutting saw completes craniotomy; frontal sinus posterior wall removed for cranialization; nasofrontal ducts plugged
6. Dural elevation: dura elevated from the anterior cranial fossa floor; crista galli attachments divided and removed; olfactory dural sleeves divided
7. Facial approach: simultaneous or staged; nasal/facial incisions for inferior exposure (may include lateral rhinotomy, Weber-Ferguson, or endoscopic endonasal)
8. En-bloc resection: cribriform plate + dura + olfactory bulbs ± brain parenchyma depending on tumor extent
9. Skull base reconstruction: pericranial flap placed to cover the dural repair (does not require skin grafting - mucosalizes spontaneously); frontal sinus cranialized if large; frontonasal ducts obliterated

Key Points

• Can be combined with a facial incision or endoscopic approach to tailor to tumor location
• The interfascial technique protects the frontal branches of the facial nerve during temporal dissection
• Medial canthal ligament must be reidentified and secured at closure; canalicular stents placed to prevent dacryostenosis
• Contraindications (per Donald): brainstem invasion, superior sagittal sinus involvement, bilateral ICA or bilateral cavernous sinus involvement, distant metastatic disease

2. Basal Subfrontal Approach (Transbasal Approach)

Indications

• Lesions primarily involving the sphenoid body and upper clivus
• Meningiomas, fibrous dysplasia, chordomas, chondrosarcomas, ossifying fibromas

Technique

• Bicoronal incision; bifrontal craniotomy
• Orbital osteotomies: bilateral orbital roofs and supraorbital bar temporarily removed (coronal osteotomy as far posterior as the posterior ethmoid foramen)
• Provides very broad basal exposure of the entire anterior cranial base
• Completion by drilling/rongeuring bone to unroof the optic nerves, superior orbital fissures, and sphenoid sinus

3. Transfacial Approaches (Open Extracranial)

a. Lateral Rhinotomy

• Paranasal skin incision ± partial maxillectomy
• Access: maxilla, ethmoid, anterior sphenoid, nasopharynx, pterygopalatine fossa
• Indications: invasive sinonasal tumors involving anterior nasal cavity, facial skin, dentition/palate

b. Weber-Ferguson Incision

• Extension of lateral rhinotomy incorporating lip split and infraorbital extension
• Wider access to the maxilla and central skull base

c. Midfacial Degloving

• Sublabial incision with bilateral intercartilaginous nasal incisions - no external skin scar
• Access: large central compartment lesions via nose and both maxillary sinuses; medial maxillectomy; resection of ascending process of palatine bone
• Contraindicated when tumor involves facial skin

d. Anterior-Lateral Maxillary Swing (Wei approach, 1998)

• Provides access to the central skull base including nasopharynx
• Long-term results: 78% clear margins achieved; 5-year local control 75% (in selected patients)

4. Expanded Endonasal Endoscopic Approach (EEA)

Advantages

• Avoids large transfacial and scalp incisions
• Better visualization through magnification and angled scopes (0°, 30°, 45°, 70°)
• Avoids frontal lobe retraction
• 5-year survival in endoscopic management of sinonasal malignancies: up to 60%, comparable to traditional craniofacial resection

Disadvantages/Limitations

• Limited lateral exposure
• Hemostasis more challenging
• Higher incidence of CSF leak (addressed by vascularized nasoseptal flap)
• No RCTs comparing open vs. endoscopic (ethically and logistically difficult to design)

Ideal Lesions

• Small midline lesions
• Pituitary adenomas, craniopharyngiomas, olfactory groove meningiomas, planum sphenoidale meningiomas, sinonasal malignancies without lateral extension

Contraindications (KJ Lee)

• Orbital involvement
• Involvement of the far lateral maxillary sinus
• Dural involvement lateral to the orbit
• Invasion of brain parenchyma
• Cavernous sinus or carotid involvement
• Lesion lateral to the cavernous carotid or superolateral to the optic nerve

Operative Steps (Endoscopic Transcribriform Resection)

1. Nasoseptal (Hadad-Bassagasteguy) flap harvested and tucked in nasopharynx for later reconstruction
2. Tumor debulked endonasally to visualize margins, origin, skull base involvement
3. Bilateral maxillary antrostomies, total ethmoidectomy, sphenoidotomy for landmark identification; optic and carotid canals visualized
4. Draf III procedure (modified Lothrop) to remove frontal sinus floor
5. Nasal septum transected below tumor to the sphenoid rostrum
6. Anterior and posterior ethmoid arteries ligated and divided at skull base
7. Anterior skull base drilled thin and elevated - removed from crista galli to planum sphenoidale, from medial orbital wall to contralateral medial orbital wall
8. Dura cauterized and opened around tumor with margin
9. Cortical blood vessels elevated; olfactory roots transected
10. Margins confirmed via multiple frozen sections
11. Multilayered dural closure: subdural dural graft matrix → fascia graft → vascularized nasoseptal flap → fibrin glue → gelfoam/fat
12. Nasal packing; nasal trumpets to preserve airway and prevent pneumocephalus; tracheotomy may be used in selected cases

The Hadad-Bassagasteguy Nasoseptal Flap

5. Endoscopic Transcribriform Approach

• Resects from orbit to orbit; sphenoid to Draf III frontal opening
• Middle turbinate, ethmoids, sphenoid, and frontal sinus contents all removed and opened into a flat plane along the cranial fossa floor
• Often performed bilaterally with septum resection
• Bony skull base drilled away from the dura with binasal access
• Lateral orbital extension allows dural resection lateral to the orbital lamina

6. Keyhole / Supraorbital Craniotomy

• Minimally invasive craniotomy made through an eyelid ("eyebrow") incision above the supraorbital rim
• Better visualization of deep structures; reduced frontal lobe retraction vs. standard bifrontal craniotomy
• Used for select anterior skull base lesions accessible from a superolateral direction
• Can be combined with endoscope for additional visualization

7. Preoperative Vascular Assessment

• Cerebral angiography: identifies blood supply, tumor vascularity, ICA involvement, circle of Willis anatomy, collateral circulation
• Balloon Test Occlusion (BTO): temporary ICA occlusion with balloon catheter; patient kept awake for serial neurologic assessment over 15 minutes; failure = high stroke risk with ICA sacrifice
• Even with fully passed BTO, 2-20% ischemic stroke risk remains after operative ICA occlusion
• Adjuncts to BTO: hypotensive challenge, TCD, SPECT (Tc-99m), MR perfusion, near-infrared spectroscopy - no single combination has proven definitively superior

Transsphenoidal Approach - A Detailed Note

Historical Development

• The microscopic sublabial transsphenoidal approach was the standard for decades
• The endoscopic endonasal transsphenoidal approach has largely replaced the microscopic approach at most major centres
• The endonasal route avoids the sublabial incision, reduces oral morbidity, and provides wider panoramic visualization

Anatomical Corridor

1. Nasal cavity → 2. Posterior nasal septum / rostrum of sphenoid → 3. Sphenoid sinus → 4. Sellar floor → 5. Sella turcica

Key Steps

1. Patient in supine position, head slightly extended and turned to surgeon
2. Bilateral sphenoidotomy with identification of the sellar floor, opticocarotid recesses, and the carotid prominences
3. Sellar floor opened with drills and punch; dura incised in a cruciate fashion
4. Tumor removal with ring curettes, angled dissectors, and suction
5. Intraoperative MRI or neuronavigation often used for confirmation of resection
6. Skull base reconstruction: fat graft ± fascia lata ± nasoseptal flap (if dural violation)

Indications

• Pituitary adenomas (micro and macro)
• Craniopharyngioma (sellar/suprasellar)
• Rathke's cleft cyst
• Pituitary apoplexy
• Meningiomas of the planum sphenoidale or tuberculum sellae
• Chordoma (central clivus)
• Any midline central skull base pathology accessible via the EEA

Limitations of Transsphenoidal Approach

• Limited access to suprasellar extension when the diaphragma sellae does not descend
• Cannot reach lesions lateral to the ICA (cavernous sinus - high risk of ICA injury)
• Limited lateral exposure compared to transcranial approach
• Dependent on tumor consistency (fibrous tumors are harder to remove)

Complications

• CSF leak / rhinorrhoea - most common significant complication
• Diabetes insipidus - transient (~20%) or permanent (~2%)
• Hypopituitarism - related to normal gland manipulation
• ICA injury - rare but catastrophic (<1%, higher in revision cases)
• Meningitis / intracranial infection
• Visual deterioration (from optic nerve/chiasm manipulation)
• Epistaxis, septal perforation (minor)

Endoscopic vs. Microscopic Transsphenoidal