Surgical Approaches to the Pterygopalatine Fossa (PPF)

A Comprehensive 50-Mark Answer

1. INTRODUCTION

2. SURGICAL ANATOMY OF THE PPF

2.1 Boundaries

2.2 Communications (Critical for Surgical Planning)

                        ┌─────────────────────────────────┐
                        │    PTERYGOPALATINE FOSSA         │
                        └────────────┬────────────────────┘
          ┌─────────────┬────────────┼──────────────┬──────────────┐
          ▼             ▼            ▼              ▼              ▼
   Nasal Cavity   Middle Cranial   Orbit      Infratemporal   Oral Cavity
  (Sphenopalatine  Fossa          (Inferior    Fossa          (Pterygopalatine
   Foramen)       (Foramen        Orbital     (Pterygo-        Canal →
                   Rotundum,       Fissure)    maxillary       Greater &
                   Vidian Canal)               Fissure)        Lesser
                                                               Palatine For.)

2.3 Contents

• Arterial: Third (pterygopalatine) part of the maxillary artery and its branches:
  • Sphenopalatine artery (→ nasal cavity)
  • Descending palatine artery (→ palate)
  • Infraorbital artery (→ orbit)
  • Posterior superior alveolar artery
  • Pharyngeal artery
  • Artery of pterygoid canal (Vidian artery)
• Neural:
  • Maxillary nerve (V2) entering via foramen rotundum → gives infraorbital nerve, zygomatic nerve, and ganglionic branches
  • Pterygopalatine ganglion (parasympathetic ganglion of CN VII via Greater Petrosal Nerve; sensory from V2; sympathetic from deep petrosal nerve)
  • Nerve of pterygoid canal (Vidian nerve) = Greater Petrosal + Deep Petrosal nerves
• Venous: pterygoid venous plexus (via pterygomaxillary fissure)

3. FLOWCHART: DECISION MAKING IN PPF SURGERY

                   ┌────────────────────────────────────┐
                   │  SUSPECTED PPF PATHOLOGY            │
                   │  (tumor / neuralgia / epistaxis)    │
                   └────────────────┬───────────────────┘
                                    │
                    ┌───────────────▼──────────────────┐
                    │  High-Resolution CT + MRI (3T)    │
                    │  + Angiography (if vascular)      │
                    └───────────────┬──────────────────┘
                                    │
             ┌──────────────────────▼─────────────────────────┐
             │           ASSESS EXTENT OF DISEASE              │
             └────┬──────────────┬───────────────┬────────────┘
                  │              │               │
          ┌───────▼──────┐ ┌────▼──────┐ ┌─────▼──────────────┐
          │ Confined to  │ │Extension  │ │ Extension into      │
          │ PPF only     │ │to ITF /   │ │ middle cranial      │
          │              │ │Orbit      │ │ fossa / cavernous   │
          └───────┬──────┘ └────┬──────┘ │ sinus               │
                  │              │        └─────┬──────────────┘
                  │              │              │
     ┌────────────▼─┐  ┌─────────▼──────┐  ┌──▼──────────────────┐
     │ Endoscopic   │  │ Endoscopic +   │  │ Combined Open +     │
     │ Endonasal    │  │ Transmaxillary │  │ Endoscopic / Cranio │
     │ (EEA)        │  │ or Caldwell-Luc│  │ -facial approach    │
     └──────────────┘  └───────────────┘  └─────────────────────┘

4. CLASSIFICATION OF SURGICAL APPROACHES

APPROACHES TO PTERYGOPALATINE FOSSA
│
├── A. ENDOSCOPIC APPROACHES
│     ├── 1. Endoscopic Endonasal Approach (EEA) / Transnasal
│     └── 2. Endoscopic Transmaxillary (Transantral) Approach
│
├── B. OPEN APPROACHES
│     ├── 3. Transantral Approach (Caldwell-Luc)
│     ├── 4. Transpalatal Approach
│     ├── 5. Midfacial Degloving
│     ├── 6. Lateral Rhinotomy + Medial Maxillectomy
│     └── 7. Total Maxillectomy (infrastructure / total)
│
├── C. SKULL BASE / COMBINED APPROACHES
│     ├── 8. Infratemporal Fossa Approaches (Fisch Types A-D)
│     ├── 9. Preauricular Subtemporal Approach (Al-Mefty)
│     ├── 10. Transcranial Approach (middle fossa floor)
│     └── 11. Combined Cranio-Endoscopic Approaches
│
└── D. MINIMALLY INVASIVE / PERCUTANEOUS
      └── 12. Image-guided PPF nerve block / trigeminal neuralgia treatment

5. DETAILED DESCRIPTION OF EACH APPROACH

APPROACH 1: ENDOSCOPIC ENDONASAL APPROACH (EEA) / TRANSNASAL APPROACH

• Sphenopalatine artery ligation (uncontrolled epistaxis)
• Vidian neurectomy (vasomotor rhinitis)
• Biopsy of PPF lesions
• JNA confined to PPF/nasal cavity (Radkowski Grade I–IIA)
• Pterygopalatine ganglion neuralgia (surgical approach)

Step-by-step Technique:

ENDOSCOPIC ENDONASAL APPROACH – OPERATIVE STEPS
│
├── STEP 1: Patient positioning
│     └── Supine, 15–20° reverse Trendelenburg, head turned 15° toward surgeon
│
├── STEP 2: Decongestion + Anesthesia
│     └── Topical xylometazoline + submucosal local anesthetic with epinephrine
│
├── STEP 3: Identify anatomical landmarks
│     └── Middle turbinate, uncinate process, natural maxillary ostium,
│         posterior wall of maxillary sinus, crista ethmoidalis
│
├── STEP 4: Crista ethmoidalis identification
│     └── Bony crest on posterior maxillary wall just anterior to
│         sphenopalatine foramen; key landmark
│
├── STEP 5: Mucosal incision
│     └── Vertical incision over lateral nasal wall posterior to
│         the attachment of the middle turbinate
│
├── STEP 6: Sphenopalatine foramen identification
│     └── Just posterior to crista ethmoidalis at level of posterior
│         maxillary fontanelle
│
├── STEP 7: Entry into PPF
│     └── Remove posterior wall of maxillary sinus (posterior antrostomy)
│         or directly widen sphenopalatine foramen with Kerrison punch
│
├── STEP 8: Identify sphenopalatine artery / maxillary artery
│     └── Clips / bipolar cautery applied to SPA for epistaxis ligation
│
└── STEP 9: Vidian canal identification (if neurectomy planned)
      └── Floor of sphenoid sinus → Vidian canal at junction of
          pterygoid process and sphenoid body

APPROACH 2: ENDOSCOPIC TRANSMAXILLARY (TRANSANTRAL) APPROACH

• JNA with extension into pterygomaxillary fissure and ITF
• Nerve sheath tumors of V2
• Schwannomas of PPF
• Perineural spread evaluation along V2

Technique:

ENDOSCOPIC TRANSMAXILLARY APPROACH – OPERATIVE STEPS
│
├── STEP 1: Wide middle meatal antrostomy (Caldwell-Luc incision or endoscopic)
│
├── STEP 2: Identify posterior wall of maxillary sinus
│     └── Corresponds to the anterior wall of PPF
│
├── STEP 3: Remove posterior antral wall
│     └── Using drill, Kerrison punch, or microdebrider
│         → Creates wide anterolateral corridor into PPF
│
├── STEP 4: Identify fat pad of PPF (characteristic yellow fat)
│     └── Confirms entry; contains maxillary artery and V2
│
├── STEP 5: Identify and control maxillary artery
│     └── Artery is superficial (anterior) to V2
│         Ligate or clip branches selectively
│
├── STEP 6: Trace V2 nerve
│     └── Nerve travels superomedially to foramen rotundum
│
├── STEP 7: Vidian nerve identification
│     └── Drill pterygoid process to expose Vidian canal
│
└── STEP 8: Tumor removal / biopsy / ligation

Intraoperative image (endoscopic dissection of PPF showing neurovascular planes):

Intraoperative endoscopic view of the PPF/ITF during transmaxillary-pterygoid approach showing: maxillary artery (MA) and its branches — infraorbital artery (IOA), sphenopalatine artery (SPA), descending palatine artery (DSA); maxillary nerve (V2) entering foramen rotundum; and Gasserian ganglion. Note the superficial arterial plane anterior to the deeper neural plane.

APPROACH 3: TRANSANTRAL APPROACH (CALDWELL-LUC)

• Classic open approach to PPF
• Maxillary artery ligation for epistaxis
• Drainage of PPF abscess
• Biopsy of posterolateral maxillary sinus / PPF tumors

CALDWELL-LUC APPROACH – OPERATIVE STEPS
│
├── STEP 1: Incision
│     └── Horizontal sublabial incision in gingivobuccal sulcus
│         (above upper premolars, 0.5 cm above gingival margin)
│
├── STEP 2: Elevation of mucoperiosteal flap
│     └── Subperiosteal dissection to expose anterior maxillary wall
│         Preserve infraorbital nerve (exits infraorbital foramen)
│
├── STEP 3: Antrostomy
│     └── Perforation with osteotome or drill in canine fossa area
│         Enlarge with Kerrison punch (minimum 2 × 2 cm window)
│
├── STEP 4: Exploration of maxillary sinus
│     └── Identify posterior sinus wall
│
├── STEP 5: Breach posterior antral wall
│     └── Reveals PPF fat pad
│
├── STEP 6: Identify maxillary artery
│     └── Clip / ligate for epistaxis management
│
└── STEP 7: Closure
      └── Primary closure of mucosal flap; nasal antrostomy for drainage

APPROACH 4: TRANSPALATAL APPROACH

• PPF lesions extending inferiorly toward pterygopalatine canal
• Selected cases of nasopharyngeal angiofibroma with inferior extension
• Access to pterygoid plates and posterior nasal choanae

TRANSPALATAL APPROACH – STEPS
│
├── STEP 1: Palatal incision
│     └── Midline palatal incision from posterior hard palate edge
│         or U-shaped incision based on greater palatine vessels
│
├── STEP 2: Elevation of palatal mucoperiosteum
│     └── Preserve greater and lesser palatine neurovascular bundles
│
├── STEP 3: Drill posterior hard palate / pterygoid plates
│     └── Exposes pterygopalatine canal → pterygopalatine fossa inferiorly
│
├── STEP 4: Tumor access / hemostasis
│
└── STEP 5: Closure
      └── Primary re-suturing of palatal flap

APPROACH 5: MIDFACIAL DEGLOVING APPROACH

• Extensive lesions of nasal cavity, PPF, and maxillary sinus bilaterally
• JNA (Radkowski Grade IIA–IIB)
• Inverted papilloma with PPF extension

MIDFACIAL DEGLOVING – STEPS
│
├── STEP 1: Combined intranasal and sublabial incision
│     └── Bilateral intercartilaginous (between upper and lower lateral
│         cartilages) + transfixion incisions combined with
│         bilateral sublabial (Caldwell-Luc level) incisions
│
├── STEP 2: Degloving of midfacial soft tissues
│     └── Entire midfacial skin elevated off bony framework
│         → Exposes bilateral maxillary sinuses, nasal cavity,
│           pterygoid plates bilaterally
│
├── STEP 3: Posterior antrostomy bilaterally
│     └── Access both PPF regions
│
├── STEP 4: Tumor removal
│
└── STEP 5: Closure
      └── Replace degloved soft tissue; suture incisions

APPROACH 6: LATERAL RHINOTOMY + MEDIAL MAXILLECTOMY

• Malignant tumors of nasal cavity with PPF involvement
• Inverted papilloma with extensive PPF involvement
• Sinonasal undifferentiated carcinoma

APPROACH 7: TOTAL MAXILLECTOMY

• Infrastructure maxillectomy: Removes hard palate + lower maxilla (below infraorbital nerve). Limited PPF access.
• Total maxillectomy: Removes entire maxilla including orbital floor — excellent PPF exposure. Orbital content may be preserved or removed depending on tumor extent.
• Extended total maxillectomy: Includes pterygoid plates, orbital exenteration for maximum access.

APPROACH 8: INFRATEMPORAL FOSSA APPROACHES (FISCH CLASSIFICATION)

Fisch ITF Approach Classification:

FISCH TYPE C APPROACH – OPERATIVE STEPS
│
├── STEP 1: Preauricular (hemicoronal) incision
│     └── Extended into neck for ICA control if needed
│
├── STEP 2: Zygomatic arch osteotomy
│     └── Detach at root + anteriorly; reflect inferiorly
│         with temporalis muscle (improves exposure)
│
├── STEP 3: Mandibular condyle anterolateral displacement
│     └── OR coronoidectomy to improve access
│
├── STEP 4: Remove lateral pterygoid plate
│     └── Exposes ITF + lateral wall of PPF
│
├── STEP 5: Ligate / embolize maxillary artery
│     └── Proximal control then distal dissection
│
├── STEP 6: Access PPF contents
│     └── V2, maxillary artery branches, PPF tumor
│
├── STEP 7: If ICA involvement
│     └── Dissect petrous ICA with vascular control
│
└── STEP 8: Reconstruction
      └── Temporalis muscle flap; titanium plate for zygomatic arch;
          fat obliteration of dead space

APPROACH 9: COMBINED ENDOSCOPIC-ASSISTED APPROACHES (RECENT ADVANCES)

• Endoscopic endonasal + Fisch C: Endoscope provides medial visualization while open approach provides lateral control — "two-corridor" concept
• Endoscopic transmaxillary-pterygoid approach: Single corridor accessing PPF and ITF; allows Vidian canal drilling, pterygoid plate removal, and access to foramen rotundum — all endoscopically

6. SPECIFIC INDICATIONS AND APPROACH SELECTION

6.1 Juvenile Nasopharyngeal Angiofibroma (JNA) — Most Common PPF Tumor

Pre-operative embolization (24–48 hours before surgery) is mandatory for JNA to reduce intraoperative blood loss (Dhingra; Hazarika).

6.2 Maxillary Artery Ligation for Epistaxis

ALGORITHM: SURGICAL MANAGEMENT OF REFRACTORY EPISTAXIS
│
├── Failed conservative measures
│     └── Anterior + posterior nasal packing × 48–72 hrs
│
├── Endoscopic sphenopalatine artery ligation (ESAL)
│     └── First-line surgical option
│         Approach: Endoscopic endonasal via sphenopalatine foramen
│         Clip/cauterize SPA and its branches
│
├── If ESAL fails → Maxillary artery ligation in PPF
│     └── Endoscopic transmaxillary or Caldwell-Luc approach
│
├── Anterior + posterior ethmoidal artery ligation
│     └── Lynch incision (external frontoethmoidectomy)
│         OR transorbital endoscopic approach
│
└── External carotid artery ligation (rare, last resort)
    OR Interventional radiology embolization

6.3 Vidian Neurectomy

1. Transantral (Caldwell-Luc): Classic approach — enter PPF via posterior antral wall, identify Vidian canal at base of pterygoid process, divide Vidian nerve
2. Transnasal (Chandra's approach): Transseptal
3. Endoscopic endonasal: Most widely used currently — drill sphenoid floor to expose Vidian canal; coagulate/divide Vidian nerve at ganglion

7. SURGICAL ANATOMY DIAGRAM — NEURAL AND VASCULAR PLANES

Lateral skull anatomy showing pterygopalatine fossa, foramen rotundum, V2, and V3:

Lateral skull view showing the pterygopalatine fossa anterior to the lateral pterygoid plate. V2 (maxillary nerve) enters via foramen rotundum; V3 (mandibular nerve) exits via foramen ovale posterior to pterygoid plate. Understanding these relationships is critical for all surgical approaches.

8. COMPLICATIONS OF PPF SURGERY

9. RECENT ADVANCES

9.1 Fully Endoscopic Skull Base Surgery

• Expanded Endoscopic Endonasal Approaches (EEEA) now allow access to the entire PPF and beyond, including the cavernous sinus and Meckel's cave, without any external incision (Kassam, Gardner, Snyderman — Pittsburgh group)
• Binostril four-hand technique: Allows bimanual dissection, hemostasis, and tumor removal simultaneously
• The transmaxillary-pterygoid corridor is now the standard for PPF endoscopic access in most tertiary centers

9.2 Neuronavigation and Image Guidance

• Intraoperative CT/MRI navigation is now standard for PPF surgery, especially with tumors distorting normal anatomy
• Real-time navigation reduces vascular and neural injury rates
• Intraoperative fluorescence angiography (ICG-based) for vascular mapping of maxillary artery branches

9.3 Pre-operative Embolization

• DynaCT angiography allows superselective embolization of feeding vessels (internal maxillary artery branches) for JNA with >90% devascularization
• Embolization 24–48 hours pre-operatively significantly reduces blood loss and conversion rates

9.4 Robotic Surgery

• Transoral robotic surgery (TORS) extended to nasopharyngeal and PPF lesions — limited reports but promising for inferior PPF access
• Da Vinci system studies (2018–2022) showed feasibility for selected benign PPF tumors

9.5 Augmented Reality and 3D Planning

• 3D CT-printed models of PPF allow preoperative surgical simulation
• Augmented reality overlays during surgery improve identification of Vidian canal, foramen rotundum, and maxillary artery

9.6 Proton Beam Radiotherapy as Adjunct

• For residual/recurrent intracranial JNA or malignant PPF tumors — proton beam therapy allows focal high-dose radiation with minimal normal tissue damage

9.7 Endoscopic PPF Approach for Trigeminal Neuralgia

• Endoscopic pterygopalatine ganglion block and neurolysis under direct visualization
• Evolving as alternative to percutaneous approaches, especially when CT-guided access is technically difficult

10. SUMMARY FLOWCHART — APPROACH SELECTION

PPF PATHOLOGY IDENTIFIED
         │
         ├─── BENIGN, SMALL (confined to PPF medially)
         │         └──► ENDOSCOPIC ENDONASAL APPROACH (EEA)
         │
         ├─── BENIGN, MODERATE (PPF + posterior maxillary sinus)
         │         └──► ENDOSCOPIC TRANSMAXILLARY or CALDWELL-LUC
         │
         ├─── VASCULAR TUMOR (JNA) — Grade IIA/IIB
         │         └──► Pre-op embolization → Endoscopic / Midfacial Degloving
         │
         ├─── VASCULAR TUMOR (JNA) — Grade IIC/III
         │         └──► Pre-op embolization → Fisch Type C (± endoscopic assist)
         │
         ├─── MALIGNANT, NO SKULL BASE
         │         └──► Total Maxillectomy ± Orbital Exenteration (Weber-Ferguson)
         │
         ├─── MALIGNANT, SKULL BASE INVOLVEMENT
         │         └──► Combined cranio-facial + endoscopic (multidisciplinary)
         │
         └─── INTRADURAL EXTENSION
                   └──► Craniotomy + Endoscopic combined approach
                         (Neurosurgery + ENT joint)

11. COMPARISON TABLE: OPEN vs. ENDOSCOPIC APPROACHES

12. KEY POINTS FOR EXAMINATION (50-Mark Recap)

1. PPF is a pyramidal space with 6 walls, 5 foramina/communications — knowledge of all is essential
2. Contents: Maxillary artery (3rd part) + V2 + pterygopalatine ganglion + Vidian nerve
3. Endoscopic approaches have largely replaced open approaches for benign disease
4. Fisch Type C remains gold standard for large tumors with ITF/skull base extension
5. JNA is the prototype tumor requiring PPF access — stage-based approach selection
6. Sphenopalatine artery ligation via endoscopic endonasal approach is first-line surgical treatment for refractory epistaxis
7. Vidian neurectomy via endoscopic route is performed for vasomotor rhinitis (now rarely done)
8. Neuronavigation is standard of care in modern PPF surgery
9. Pre-operative embolization is mandatory for vascular tumors (JNA)
10. Complications — most serious are maxillary artery hemorrhage and V2 injury

REFERENCES

Clinical Pearl: The key to safe PPF surgery is the recognition of the two planes within the fossa — the superficial arterial plane (maxillary artery coursing anteriorly) and the deeper neural plane (V2 and pterygopalatine ganglion). Always identify the artery first, then work deeper to the nerve. This principle applies across all approaches, whether open or endoscopic.