The maxillary nerve — the second branch of the trigeminal nerve — is the primary sensory nerve of the mid-face, responsible for sensation in the upper jaw, the sides of the nose, and the upper lip. Although brain tumors compressing this nerve are uncommon (accounting for 2.3% of intracranial tumors), the misdiagnosis rate is as high as 58.7%. Pain triggered by toothbrushing is a hallmark warning sign. Early intervention can raise the functional preservation rate to 79.4%; delayed treatment risks permanent sensory loss.

I. Symptoms of Brain Tumor Compression of the Maxillary Nerve

Symptoms of maxillary nerve compression follow a progressively worsening course and are frequently misattributed to dental conditions in the early stages.

The Sensory Triad

•  Lightning-bolt pain: Sudden electric shock-like pain in the upper jaw region, lasting seconds, typically triggered by toothbrushing or washing the face.

•  Progressive numbness: Gradually diminishing sensation alongside the nose and in the upper lip area, often described as the feeling of a patch of tape stuck to the skin.

• Paresthesia: Crawling or burning sensations that, in later stages, give way to persistent numbness.

Motor Dysfunction

•  Reduced chewing efficiency (weakness of the posterior molars)

•  Jaw deviation toward the affected side (involvement of the medial pterygoid muscle)

•  Dental occlusal discomfort (proprioceptive disturbance)

Involvement of Adjacent Structures

•  Infraorbital nerve compression (numbness of the lower eyelid)

•  Pterygopalatine fossa invasion (nasal dryness, nosebleeds)

•  Cavernous sinus involvement (diplopia, extraocular muscle palsy)

II. Common Tumor Types and Localization

Trigeminal Schwannoma (41.2%)

•  Originates from the trigeminal ganglion (Gasserian ganglion)

•  Classic MRI appearance: "dumbbell-shaped" growth spanning the middle cranial fossa and pterygopalatine fossa

•  Bone window CT shows enlargement of the foramen rotundum (>3 mm)

Pterygopalatine Fossa Meningioma (28.7%)

•  Arises from the medial plate of the pterygoid process of the sphenoid bone

•  Prominent "dural tail sign" on contrast-enhanced imaging

•  Prone to encasing the maxillary artery, increasing intraoperative bleeding risk

Nasopharyngeal Carcinoma with Skull Base Invasion (18.3%)

•  Enters the middle cranial fossa via the foramen lacerum

•  Associated with infratemporal fossa lymph node metastases

•  Multiple cranial nerve palsies appear early in the course

Juvenile Angiofibroma (9.5%)

•  Predominantly affects adolescent males

•  Highly vascularized tumor (intraoperative blood loss typically exceeds 800 ml)

•  Partially responsive to hormonal therapy

III. Diagnostic Pathway

Preferred Imaging Protocol

• 3.0T MRI thin-slice scanning: Slice thickness of 0.8 mm for clear visualization of the nerve-tumor interface

•  CT three-dimensional reconstruction: Assessment of the degree of bony destruction in the pterygopalatine fossa

•  DSA angiography: Identification of the tumor's feeding arteries (branches of the maxillary artery)

Mandatory Functional Assessment

•  Pin-prick sensory testing (sensory loss at the infraorbital foramen)

•  Quantitative thermal sensory analysis (delayed laser-evoked potentials)

•  Masticatory muscle electromyography (denervation potentials in the medial pterygoid)

Key Differential Diagnoses

•  Maxillary sinusitis: Sinus CT shows mucosal thickening; responds to antibiotics

•  Odontogenic neuralgia: Dental radiograph reveals periapical pathology; local anesthetic block provides relief

•  Cluster headache: Accompanied by conjunctival injection; responds well to oxygen inhalation

IV. Stratified Treatment

Indications for Surgical Intervention

•  Tumor diameter exceeding 2.5 cm with progressive neurological deficits

•  Annual growth rate exceeding 20%

•  Drug-refractory pain (failure of carbamazepine)

Microsurgical Approach Selection

• Transmaxillary sinus approach: For tumors in the inferior pterygopalatine fossa

• Infratemporal fossa approach: For lesions involving the middle cranial fossa and infratemporal sulcus

• Endoscopic endonasal approach: Gross total resection rate of 81.3% for midline tumors

Nerve Protection Techniques

• Intraoperative neurophysiological monitoring (protection of facial nerve branches)

• Fluorescence-guided resection (5-ALA labeling of tumor cells)

• Nerve sheath anastomosis (direct suture for defects under 2 cm)

Stereotactic Radiotherapy

• CyberKnife marginal dose of 14 Gy (5-year control rate: 83.7%)

• Indications: Postoperative residual tumor or patients at high surgical risk

• Complications: Radiation-induced osteonecrosis (incidence: 12.3%)

V. Functional Rehabilitation

Sensory Retraining

• Facial sensory re-education (identification of different fabric textures)

• Protective sensory training (guarding against burns and mechanical injury)

• Mirror visual feedback therapy (addressing sensory mismatch)

Chewing Function Rehabilitation

• Progressive occlusal force training (advancing from liquid to solid foods)

• Temporomandibular joint range-of-motion maintenance (mouth-opening exercise devices)

• Nutritional support (high-protein, easy-to-chew diet)

Long-Term Follow-Up Protocol

• MRI every 3 months during the first postoperative year

• Quantitative sensory function assessment (Semmes-Weinstein monofilament testing)

• Quality of life monitoring (QOL scale)

Frequently Asked Questions

What symptoms does brain tumor compression of the maxillary nerve cause?

The classic presentation consists of electric shock-like pain in the upper jaw region (triggered by toothbrushing or touch), numbness alongside the nose (described as a patch-of-tape sensation), and chewing weakness (difficulty with molar occlusion). Associated symptoms include nasal dryness, nosebleeds, and occasional diplopia. The pain has trigger point characteristics and does not respond to conventional analgesics.

What types of tumors compress the maxillary nerve?

The most common are trigeminal schwannomas (41.2% — benign but locally invasive), pterygopalatine fossa meningiomas (28.7% — arising from the dura), nasopharyngeal carcinoma with skull base invasion (18.3% — malignant, requiring chemoradiotherapy), and juvenile angiofibroma (9.5% — highly vascularized). Definitive diagnosis requires pathological confirmation.

How risky is surgery for a tumor at the trigeminal nerve?

Risk is stratified as follows. In the low-risk group (tumor under 2 cm, confined outside the pterygopalatine fossa), the facial nerve injury rate is 8.3%. In the intermediate-risk group (middle cranial fossa involvement), the rate of transient numbness is 37.6%. In the high-risk group (tumor encasing the internal carotid artery), the disability rate is 12.8%. Modern neuronavigation and intraoperative monitoring technologies have reduced the rate of serious complications by 42%.

Reference: https://www.incsg.com/sanchaqiaoliu/6617.html