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Sinonasal Tumor Surgery

1. Tumor Classification and Histology

• Schneiderian (sinonasal) papilloma - the most common benign nasal cavity tumor. Three subtypes: septal (exophytic, no malignant risk), inverted (most common, ~10-15% malignant transformation, arises lateral nasal wall), and cylindrical cell/oncocytic (rarest, equal or slightly higher malignant risk than inverted).
• Fibro-osseous lesions - fibrous dysplasia, ossifying fibroma, osteoma.
• Vascular lesions - hemangioma.
• Encephaloceles / meningoceles / pituitary extensions - intracranial tissue extending into the nasal cavity through skull base defects.

• Squamous cell carcinoma (SCC) - most common sinonasal malignancy.
• Adenocarcinoma - associated with woodworking dust exposure; low vs. high grade behavior differs.
• Esthesioneuroblastoma (olfactory neuroblastoma) - neuroectodermal origin from olfactory epithelium; <5% of paranasal sinus malignancies; staged by Kadish system (A: nasal cavity only; B: paranasal sinus extension; C: beyond sinuses; D: nodal/distant mets); cervical metastases in 20-25%.
• Sinonasal undifferentiated carcinoma (SNUC) - aggressive, >80% present as T4; 5-year OS 22-43%, distant mets in 65%.
• Adenoid cystic carcinoma - high propensity for perineural spread and bone invasion.
• Mucosal melanoma - all lesions are T3/Stage III at minimum; 5-year OS 25-42%.
• Neuroendocrine carcinoma - poor prognosis, rare cure without aggressive multimodal therapy.
• Rhabdomyosarcoma - most common pediatric paranasal sinus malignancy.
• Lymphoma - surgery limited to biopsy only.
• Cummings Otolaryngology, Ch. 20; K J Lee's Essential Otolaryngology, p. 598-599

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2. Preoperative Evaluation and Staging

Imaging

• CT - defines bony anatomy and identifies bony destruction; essential for surgical planning.
• MRI - better for soft tissue extent; T2-weighted sequences differentiate tumor from obstructed secretions (inflammatory signal is T2 bright; tumor is lower T2). Identifies intracranial connections, orbital involvement, and cranial nerve encasement.
• Both modalities are complementary and should be obtained together.

Ohngren's Line

AJCC Staging (Paranasal Sinuses)

• K J Lee's Essential Otolaryngology, p. 597-598

Prognostic Factors

• Histological subtype (worst: mucosal melanoma; best: minor salivary gland tumors, low-grade sarcomas)
• T stage and intracranial involvement
• Resection margins (most direct determinant of survival)
• Prior radiation / incomplete prior resection
• Nodal disease and distant metastasis

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3. Surgical Approaches

3A. Open (Transfacial) Approaches

• Lip-splitting extension (Weber-Fergusson) - adds exposure of the maxilla and orbit, permits total maxillectomy.
• Lynch-type extension - upward toward the orbit.
• Weber-Fergusson incision - incorporates lip-splitting and subciliary incisions into lateral rhinotomy for maximal maxillary exposure.

3B. Craniofacial Resection (CFR)

• Sinonasal component: resected via a transfacial approach (lateral rhinotomy or Weber-Fergusson).
• Skull base/intracranial component: via a frontal craniotomy.
• Allows en-bloc removal of the skull base and dura.
• Provides direct access for reconstruction with a pericranial flap.
• Overall 5-year survival ~50% for sinonasal cancer.
• Mortality 4.7% (higher with comorbidities).
• Morbidity 33-36%: wound complications 20%, systemic 5%, orbital 1.5% (increased by prior radiation, dural/brain invasion).

3C. Endoscopic Endonasal Approach (EEA)

1. Removal of posterior two-thirds of nasal septum.
2. Wide sphenoidotomy with intersinus septectomy.
3. Gradual debulking to identify tumor origin while preserving orientation landmarks.
4. Exposure of the skull base in the relevant module.
5. Dural opening if intracranial extension present.
6. Tumor resection.
7. Skull base reconstruction (see Section 5).

• Ethmoid cancer with cribriform plate, ethmoidal roof, or lamina papyracea involvement
• Medially located frontal sinus lesions
• Small maxillary sinus lesions (medial, superior, or posterior walls)
• Sphenoid sinus lesions
• Pterygopalatine fossa invasion and limited infratemporal fossa extension
• Periorbital extension without orbital invasion
• Anterior skull base dura or olfactory bulb invasion

• Nasal bone, palate, skin, or subcutaneous tissue invasion
• Massive frontal sinus involvement
• Maxillary lesions involving the lateral, anterior, or inferior walls
• Massive lacrimal pathway invasion
• Massive infratemporal fossa invasion
• Invasion of orbital contents
• Broad invasion of brain parenchyma or lateral extension over the orbit

• K J Lee's Essential Otolaryngology, p. 600; Cummings Otolaryngology, p. 3366-3384

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4. Histology-Specific Surgical and Multimodal Protocols

• K J Lee's Essential Otolaryngology, p. 598-599; Cummings Otolaryngology, p. 1736

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5. Skull Base Reconstruction

Defect Classification

Flap Options

• Mucosa with mucoperiosteum/mucopericondrium.
• Vascular supply: posterior septal artery (branch of sphenopalatine artery).
• Indicated for medium to large anterior and middle cranial fossa defects with high CSF leak risk.
• CSF leak rate historically <5% with this flap.
• Limitation: size of flap may not cover very large anterior defects.

• Used when prior septectomy or wide sphenoidectomy has compromised the posterior septal artery.
• Blood supply: inferior turbinate artery from posterior lateral nasal artery (sphenopalatine artery).
• Best for posterior defects (sellar, parasellar, mid-clival).
• Limitations: small size, short pedicle, restricted rotation angle.

• Supply: middle turbinate branch of posterior lateral nasal artery.
• Indicated when nasoseptal flap is unavailable; for planum sphenoidale, sellar, and fovea ethmoidalis defects.
• Advantage over inferior turbinate flap: greater length and arc of rotation.

• Based on supraorbital and supratrochlear arteries.
• Harvested externally, tunneled endoscopically through a nasion defect.
• Used for cribriform, planar, and sellar defects.
• Large-volume vascularized coverage.

• Laterally based, vascularized by anterior branch of the superficial temporal artery.
• Does not include temporalis muscle or deep temporal artery.
• Indicated for orbital, clival, and anterior/middle cranial fossa defects.

• Collagen or dermal matrix (acellular); free mucosal grafts from nasal floor, middle turbinate, or septum; fat graft for dead space obliteration (harvested from abdomen).
• Reserved for small defects only.
• K J Lee's Essential Otolaryngology, p. 601-602

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6. Special Considerations

• Orbital floor invasion alone does not mandate exenteration.
• Invasion of orbital fat or extraocular muscles is the threshold for exenteration in most centers.
• Degree of orbital involvement is a prognostic factor that also determines EEA feasibility.

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7. Complications

Endoscopic Approach Complications

Open/Craniofacial Approach Complications

• Wound complications 20%
• Systemic complications 5%
• Orbital complications 1.5%
• Mortality 4.7% (craniofacial resection)
• K J Lee's Essential Otolaryngology, p. 639; Cummings Otolaryngology, p. 3366

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8. Outcomes Summary

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1. Surgical approach selection depends on tumor location, extent, and histology - endoscopic endonasal for medially located and skull base lesions without lateral/skin/palate invasion; open/craniofacial for extensive or laterally placed disease.
2. Margin-negative resection is the single most important determinant of survival.
3. Multimodality therapy (surgery + IMRT ± chemotherapy) is standard for most malignant histologies.
4. Vascularized skull base reconstruction (especially the nasoseptal flap) has dramatically reduced CSF leak rates.
5. 2-surgeon, 4-handed endoscopic technique and intraoperative navigation are current best practices.