- The document compares the endoscopic endonasal prelacrimal approach and Denker's approach for accessing the pterygopalatine fossa and infratemporal fossa. - While both approaches provide adequate exposure of these areas, the study found the Denker's approach provides significantly greater surgical freedom and maneuverability of instruments, making it preferable for complex lesions. - However, the prelacrimal approach spares the lateral nasal wall and nasolacrimal duct, making it suitable for more restricted lesions in the lower pterygopalatine fossa or anterior infratemporal fossa.

1. JOURNAL CLUB-RHINOLOGY
Dr.Arya Nandu
ENT- HNS Resident
MMC,IOM,TUTH

2. Endoscopic Endonasal Approach to the
Pterygopalatine Fossa and Infratemporal
Fossa: Comparison of the Prelacrimal and
Denker’s Corridors
Published in: American Journel of
Rhinology andAllergy 2022
Authors:Lifeng Li, MD1,2 , Nyall R.
London, Jr., MD, PhD2,3 ,
Daniel M. Prevedello, MD2,4, and
Ricardo L. Carrau, MD, MBA2,4

3. INTRODUCTION

4. The pterygopalatine fossa constitutes the gateway for a transpterygoid approach to
access the infratemporal fossa, petrous apex and jugular foramen region.
The most common lesions originating or extending into pterygopalatine fossa and
infratemporal fossa include:
• Inverted papilloma
• nasopharyngeal angiofibroma
• pleomorphic adenoma
• trigeminal schwannoma
• adenoid cystic carcinoma
• squamous cell carcinoma

5. • EndoscopicDenker’s approach implies resection of the nasomaxillary buttress
including the nasolacrimal duct and the lateral nasal wall, has been adopted to
afford an adequate surgical exposure.
• A posterior nasal septectomy is valuable to provide contralateral access for a
Denker’s approach.

6. • Therefore, the endoscopic Denker’s approach provides an endoscopic solution
for lesions originating or extending into the pterygopalatine fossa and
infratemporal fossa, successfully avoiding facial or buccal incisions.
• For the management of malignancies involving the pterygopalatine fossa and
infratemporal fossae, the resection of the lateral nasal wall and sacrifice of the
nasolacrimal duct may be acceptable tradeoffs.

7. • For benign lesions, a less invasive approach allows a faster and complete
postoperative recovery of nasal and lacrimal function
• The prelacrimal approach is a less invasive technique, for addressing lesions
restricted to the prelacrimal recess of the maxillary sinus, to remove tumors
arising in the pterygopalatine fossa and infratemporal fossa, as well as the
management of lesions involving the orbital floor, inferior or medial intraconal
space, lateral recess of sphenoid sinus, and middle cranial fossa.

8. • The advantages of a prelacrimal approach include sparing part of the lateral
nasal wall, the nasolacrimal duct and posterior nasal septum.
• The disadvantage include limited instrument maneuverability.

9. OBJECTIVES
The study compares the potential maximum exposure of the Pterygopalatine
fossa and Infratemporal fossa and quantifies the difference in surgical freedom
via endoscopic Denker’s and prelacrimal approaches.

10. MATERIALS AND METHODS
• The study was conducted at the Anatomy Laboratory Toward Visuospatial
Surgical Innovations in Otolaryngology and Neurosurgery (ALT-VISION) at
the Wexner Medical Center of The Ohio State University, completing an
endonasal prelacrimal approach and endoscopic Denker’s approach to the
pterygopalatine fossa and infratemporal fossa in six cadaveric specimens (12
sides).
• For each specimen, one side was selected randomly for a prelacrimal
approach, and the contralateral side for an endoscopic Denker’s approach.

11. • Visualization was possible using rigid rod-lens endoscopes (4-mm diameter, 18-cm
length) with 0°, 30° and 45° lenses coupled to a high-definition camera and video
monitor.
• Both video and standard digital images were recorded during dissections using the
advanced image and data acquisition recording system

12. • A high resolution computed tomography (CT) scan was performed before the
dissection and the images were exported to a surgical navigation system
• Coordinates of the reference points were recorded, and the surface area of the
surgical field exposure was calculated using the navigation system.

13. SURGICAL STEP
• For the transnasal prelacrimal approach, following a prelacrimal incision, a vertical
mucoperiosteal incision between the pyriform aperture and anterior head of the
inferior turbinate, extending inferiorly to the nasal floor.
• Subperiosteal dissection to expose the piriform aperture and medial aspect of the
anterior maxilla.

14. • Removal of the bony attachment of the inferior turbinate and medial bony wall
of the maxillary sinus with a high-speed drill to expose the nasolacrimal duct
and enter the maxillary sinus anterolateral to the nasolacrimal duct .
• The anterior bony wall of the maxilla was removed to the level of infraorbital
foramen for further lateral exposure.

15. • Denker’s approach requires a mucoperiosteal incision inferiorly at the nasal floor
and a second mucosal incision overlying the edge of the pyriform aperture.
• A high-speed drill was then utilized to remove the lateral nasal wall and anterior
maxillary wall to the level of infraorbital foramen.
• The nasolacrimal duct is transected to establish a Denker’s corridor .

16. • After establishing surgical corridor into the maxillary sinus , infraorbital canal
identified and posterolateral wall of maxillary sinus visualised.
• After removing posterolateral wall , its periosteum and adipose tissue ,branches
of internal maxillary arteries mobilized or repected to facilitate exposure

17. Figure 1. Right side of the specimen. A) The infraorbital canal
(IOC); B) The branches of the internal maxillary artery (IMA);
C) The anterolateral border of exposure is the temporozygomatic
space. DPA: descending palatine artery, SPA: sphenopalatine artery,
IOA: infraorbital artery, PSAA: posterosuperior alveolar artery,
DTA: deep temporal artery, TM: temporalis muscle, MM: masseter
muscle, ZA: zygomatic arch.

18. Figure 2.
A) Resected area of prelacrimal approach (right side,
red highlighted) and Denker’s approach (left side, blue highlighted);
B) Endoscopic view through prelacrimal approach of right side;
C) Endoscopic view through a Denker’s approach of left side. NLD:
nasolacrimal duct. UP: upper wall, IOC: infraorbital canal,
MT: middle turbinate, PLW: posterolateral wall.

19. MEASUREMENT AND CALCULATION OF
SURGICAL FREEDOMS
Figure 3. A) As demonstrated in the CT scans with coronal, sagittal and axial planes, the mid-point of the
infraorbital canal was set as the reference point; B) Using the measurement of the anterior point as a
representation, localizing the anterior point for a prelacrimal approach at the coronal, sagittal and axial
planes was measured on the navigation; C) Surgical freedom was equal to thesurface area △SIM +△SIL, S:
superior, I: inferior, M: medial, L: lateral.

20. • The mid-point of the infraorbital canal was selected as a reference point , and the
tracked instruments were used to determine the four cardinal points (superior,
inferior, medial and lateral borders) by navigation system.
• The coordinates corresponding to these points were recorded bounding a space
defined as the surface area
• The area for surgical freedom was equal to the quadrilateral area as two
juxtaposed triangles.

21. • Surgical freedom was defined as the maximal area along which the surgeon’s
hand can move freely while holding the proximal end of a surgical instrument
and maneuvering the distal end (superior, inferior, media and lateral) of that
instrument for each specific surgical approach.
• Using the coordinate data, the area of each triangle was determined by taking
one-half the magnitude of the cross-product of the vectors formed by any two
sides of the triangle, which was calculated through the navigation system.

22. • The surgical freedom of the prelacrimal and endoscopic Denker’s approaches
was compared by t-test.
• The value was expressed as mean ±standard deviation (SD), and a probability
value of p < 0.05 was considered to be statistically significant.
• Statistical analysis was performed using the Statistica 16.0 software
STATISTICAL ANALYSIS

23. RESULTS
• The study confirms that both the prelacrimal and Denker’s approaches provide
adequate exposure of the Pterygopalatine fossa and Infratemporal fossa.
• The maximum exposure boundaries were similar for both approaches, including
the middle cranial fossa superiorly, floor of the maxillary sinus inferiorly,
zygomatic arch and temporomandibular joint laterally, and post-styloid space
posteriorly.
• However, the data revealed a statistically significant difference (p < 0.05)
regarding the surgical freedom of the prelacrimal (388.17 ±32.86 mm2) and the
endoscopic Denker’s approaches (906.35±38.38 mm2).

24. Table 1. Comparison of the surgical freedom (mm2) between the
endonasal prelacrimal approach and endoscopic Denker’s approach.

25. DISCUSSION
• Lesions restricted to the pterygopalatine fossa, located above the level of the
superior border of inferior turbinate
or the vidian canal, may be adequately exposed via a middle meatus window.
• When the lesion extend into the inferior part of the pterygopalatine fossa or
laterally into the infratemporal fossa, the inferior turbinate and the frontal process of
the maxillary bone may become an obstacle, and the resection of the lateral nasal
wall is required to facilitate exposure as conducted through a Denker’s approach.
• Although a Denker’s approach provides valuable exposure, the sacrifice of the
lateral nasal wall and the nasolacrimal duct carry the risks of post operative
crusting and epiphora.

26. • Based on the findings derived from this cadaveric study, however, the transnasal
prelacrimal approach can provide an alternative means to expose the entire
pterygopalatine fossa with preservation of the lateral nasal wall and the
nasolacrimal duct.
• Therefore, a prelacrimal approach seems particularly suitable for addressing
lesions located at the inferior portion of the pterygopalatine fossa or as a
complementary approach for the management of lesions that originate in the
nasal cavity but extends into the pterygopalatine fossa.

27. • For lesions restricted to the anterior portion of the infratemporal fossa (masticator
muscle space), the prelacrimal approach could provide a direct and sufficient
exposure with preservation of the lateral nasal wall and the nasolacrimal duct.
• Whereas lesions arising at the parapharyngeal space, requires separating the
pterygoid muscles and risking bleeding from the pterygoid plexus; thus, selection
of a surgical corridor with enhanced surgical freedom (Denker’s approach) is
critical for instrumental maneuverability and bleeding control.
• Resection of the lateral nasal wall and posterior septum via an endoscopic
Denker’s approach increases the exposure and instrumentation corridors;
therefore, improving the ability to control of bleeding from the pterygoid venous
plexus through the four-handed techniques.

28. LIMITATIONS
• The lack of tissue elasticity of cadaveric specimens may impact the exposure
of the pterygopalatine fossa and infratemporal fossa via either the prelacrimal
or Denker’s approach.
• Displacement of normal structures by tumors and their potential bleeding
cannot be emulated.

29. CONCLUSION
• The prelacrimal approach can achieve a similar anatomic exposure of the
pterygopalatine fossa and the infratemporal fossa to that of an endoscopic
Denker’s approach.
• Surgical freedom of the prelacrimal approach, however, is significantly limited;
thus, the endoscopic Denker’s approach is preferable for the management of
complex lesions which requires a high degree of instrument maneuverability.

30. THANK YOU