The Endoscopic Prelacrimal Recess Approach to the Pterygopalatine Fossa and Infratemporal Fossa

Transorbital Endoscopic Approach to the Foramen Rotundum for Infraorbital Nerve Stripping

PURPOSE

To develop and evaluate a transorbital endoscopic approach to the foramen rotundum to excise the maxillary nerve and infraorbital nerve branch.

METHODS

Cadaveric dissection study of 10 cadaver heads (20 orbits). This technique is predicated upon 1) an inferior orbital fissure release to facilitate access to the orbital apex and 2) the removal of the posterior maxillary wall to enter the pterygopalatine fossa (PPF). Angulations along the infraorbital nerve were quantified as follows: the first angulation was measured between the orbitomaxillary segment within the orbital floor and the pterygopalatine segment suspended within the PPF, while the second angulation was taken between the pterygopalatine segment and maxillary nerve as it exited the foramen rotundum. With refinement of the technique, the minimum amount of posterior maxillary wall removal was quantified in the final 5 cadaver heads (10 orbits).

RESULTS

The mean distance from the inferior orbital rim to the foramen rotundum was 45.55 ± 3.24 mm. The first angulation of the infraorbital nerve was 133.10 ± 16.28 degrees, and the second angulation was 124.95 ± 18.01 degrees. The minimum posterior maxillary wall removal to reach the PPF was 11.10 ± 2.56 mm (vertical) and 11.10 ± 2.08 mm (horizontal).

CONCLUSIONS

The transorbital endoscopic approach to an en bloc resection of the infraorbital nerve branch up to its maxillary nerve origin provides a pathway to the PPF. This is relevant for nerve stripping in the context of perineural spread. Other applications include access to the superior portion of the PPF in selective biopsy cases or in concurrent orbital pathology.

Transorbital Endoscopic Approach to the Pterygopalatine Fossa: A Less Invasive Alternative to Traditional Access

PURPOSE

The purpose of this article and accompanying video is to demonstrate a transorbital endoscopic approach for accessing the pterygopalatine fossa (PPF). This technique does not require a skin incision, avoids dissection of critical neurovascular structures, and utilizes a comparatively small osteotomy. The 2 cases presented in this article highlight the utility of a transorbital endoscopic approach for accessing an anatomic region that has traditionally required more invasive techniques to reach.

METHODS

Description of surgical technique with 2 illustrative clinical cases and accompanying surgical video.

RESULTS

Surgical technique: A trans-conjunctival approach is taken to the inferior orbital rim, and a subperiosteal dissection is propagated posteriorly. The bone of the posterior orbital floor is then deroofed, and the superior portion of the posterior wall of the maxillary sinus is removed, allowing access to the PPF for an incisional biopsy.

CASE

A 76-year-old male with a history of left cheek squamous cell carcinoma presented with progressive V2 paresthesia and an abnormally enhancing lesion in the left PPF on MRI.

CASE

A 58-year-old male with no significant medical history presented with left facial numbness (V1-V3), ptosis, an abduction deficit, and decreased hearing. Contrast-enhanced MRI demonstrated an abnormally enhanced lesion in the left PPF extending to Meckel's cave.The transorbital approach described was used to successfully obtain a diagnostic biopsy in both cases.

CONCLUSIONS

These cases highlight the utility of a transorbital endoscopic approach to the PPF as a less morbid alternative to traditional access. Patient selection is key to identifying appropriate cases.

Infratemporal Fossa Schwannoma Surgery via a Combined Prelacrimal Recess, Caldwell-Luc, and Distal Intraoral Approach

BACKGROUND

The deep location of infratemporal fossa (ITF) combined with the abundant vascular plexus in it increased the difficulty of removing the mass in ITF through endoscope surgery approach. However, under appropriate circumstances, the excision of ITF tumors through a combined prelacrimal recess, Caldwell-Luc, and distal intraoral approach can be safely performed with minimal impact on the surrounding tissues.

CASE PRESENTATION

The Department of Neurology received a 69-year-old male patient who had been experiencing headache, dizziness, and numbness from the mastoid region of his left ear to the corner of his mouth for a duration of 22 days. Cranial magnetic resonance imaging revealed the presence of a tumor located in the ITF. Following transfer to our department, surgical intervention was performed using a combined approach involving the prelacrimal recess, the anterior wall of maxillary sinus, and lateral ITF to successfully remove the tumor. Postoperative pathologic examination confirmed schwannoma as its nature. The patient was discharged in excellent condition without any functional impairment.

CONCLUSIONS

On the basis of this case, the authors believe that this combined approach can offer a distinct endoscopic perspective and adequate surgical workspace, which is crucial for tumor removal while preserving the integrity of surrounding normal tissues. Moreover, the utilization of multiple small incisions has minimal impact on postoperative recovery.

Morphometric analysis of the infratemporal fossa using three-dimensional (3D) digital models

PURPOSE

The infratemporal fossa contains important neurovascular components and is directly related to other anatomical regions and structures. The morphometric distances between the bones forming its borders have not been thoroughly investigated. The aim of this study was to determine the morphometry of the infratemporal fossa.

METHODS

3D models of the skull of 83 individuals were reconstructed from DICOM datasets, from which length, depth and width measurements were determined and compared between genders and the right and left sides.

RESULTS

All measurements obtained were significantly different between males and females. There were also significant differences between the left and right sides for depth and width measurements.

CONCLUSION

This is the first study to determine and investigate measurements of the infratemporal fossa; as such it provides a comprehensive view of the morphology of the fossa. It provides valuable information for surgical interventions and differential diagnoses of pathologies in this region, as well as enhancing its understanding in medical education.

Comparison of two surgical approaches in the management of cerebrospinal fluid rhinorrhea in the lateral recess of sphenoid sinus: A retrospective study

BACKGROUND

Cerebrospinal fluid (CSF) leakage from the lateral recess of the sphenoid sinus (LRSS) is usually repaired using endoscopic endonasal approaches, which can be challenging. Various surgical techniques have been developed for the disease.

OBJECTIVE

To report our experience with repairing CSF leak from the LRSS via transethmoid sphenoidotomy approach (TESA) and transprelacrimal recess pterygoid root approach (TPLRA), to assess the efficiency of TPLRA by comparing it with TESA.

METHODS

This retrospective study included patients with LRSS CSF rhinorrhea who underwent TESA (n = 10) or TPLRA (n = 5) from January 2011 to December 2020. Demographic characteristics and operation-related parameters were recorded.

RESULTS

The mean operation time was 169.5 and 225.0 mins in the TESA and TPLRA groups, respectively, with a mean blood loss of 65 mL and 68 mL, respectively. Histopathological examinations confirmed encephalocele in 11 (73.33%) and 4 (26.67%) cases with meningocele, respectively. CSF rhinorrhea was successfully repaired in the first attempt in both groups during the mean follow-up time of 54 months. Postoperative permanent numbness of the cheek was observed in two patients in the TESA group. No cases of lacrimal overflow or subjective dry eye were observed.

CONCLUSIONS

The TPLRA, which could be an alternative procedure to treat CSF rhinorrhea in the LRSS, provides a straight-line trajectory and effective maneuverability. We also found that CSF rhinorrhea in the LRSS was accompanied by encephalocele or meningocele, with encephalocele presenting more commonly.

Endoscopic Endonasal Approach to the Pterygopalatine Fossa and Infratemporal Fossa: Comparison of the Prelacrimal and Denker's Corridors

BACKGROUND

Both the endoscopic transnasal Denker's and prelacrimal approaches provide surgical access to the pterygopalatine fossa (PPF) and infratemporal fossa (ITF).

OBJECTIVES

This study compares the potential maximum exposure of the PPF and ITF and quantifies the difference in surgical freedom via endoscopic Denker's and prelacrimal approaches.

METHODS

Six cadaveric specimens (12 sides) were dissected using a prelacrimal approach on one side and an endoscopic Denker's approach on the contralateral side. The contents of the PPF and ITF were sequentially exposed. Surgical freedom for each corridor was subsequently calculated.

RESULTS

This study confirms that both the prelacrimal and Denker's approaches provide adequate exposure of the PPF and ITF. 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).

CONCLUSION

When compared with an endoscopic Denker's approach, a prelacrimal approach seems to achieve a similar extent of exposure (ie, visualization) of the PPF and ITF. Nonetheless, the endoscopic Denker's approach offers superior surgical freedom; thus, it is preferred for the management of complex lesions which requires increased instrument maneuverability with a 3- or 4-handed technique.

The endoscopic prelacrimal recess approach to the paramedian middle cranial base: An anatomical study

BACKGROUND

Endoscopic endonasal approach to paramedian cranial base implies sacrifice of the nasal structures.

OBJECTIVE

The present study aimed to illustrate the anatomy and provide critical anatomical landmarks for the endoscopic prelacrimal recess approach (PLRA) to the paramedian middle cranial base.

METHODS

Anatomical dissections were performed in 10 cadaveric specimens.

RESULTS

Successful access to the paramedian middle cranial base was achieved in all dissections via the PLRA with the removal of the pterygoid process. For the dissection of the infratemporal fossa and pterygopalatine fossa, the buccal nerve and infraorbital neurovascular bundle can serve as important anatomic landmarks to identify the detailed structures. In the upper parapharyngeal space, the stylopharyngeal aponeurosis can present as anatomical barriers to protect the parapharyngeal segment of the internal carotid artery (PPICA); while the levator veli palatini muscle can be considered as a landmark to locate the PPICA. For the dissection of the Eustachian tube (ET), the isthmus of the ET and ET sulcus can serve as useful landmarks to identify the posterior genu of the ICA and horizontal segment of the petrous ICA respectively.

CONCLUSION

The PLRA to the paramedian middle cranial base is anatomically feasible and can facilitate preservation of the integrity of nasal structures. The buccal nerve, infraorbital neurovascular bundle, levator veli palatini muscle, stylopharyngeal aponeurosis, the isthmus of the ET, and ET sulcus can serve as critical anatomic landmarks in their respective region and may facilitate the application of this approach.

Prevalence of the prelacrimal recess in maxillary sinus and its medial bony wall dimensions

OBJECTIVE

To investigate the occurrence rate of the prelacrimal recess (PLR) and its medial bony wall dimensions based on the radiological analysis to help surgeons enhance the understanding of anatomic structures for the endoscopic prelacrimal recess approach.

METHODS

Cone-beam computed tomography images of 255 patients were evaluated retrospectively. The prevalence of the PLR in maxillary sinus was investigated and the thickness of its medial bony wall was measured and statistically assessed. Meanwhile, the width of the PLR was measured. The correlation between the width of the PLR and its medial bony wall thickness was assessed. The data were compared between the left side and right side, male and female.

RESULTS

The PLR was present in 82.5% of the maxillary sinus, with no significant differences between the left and right sides, as well as different gender groups. The mean thickness of the medial bony wall of the PLR was 2.84 ± 1.41 mm, without statistical difference between the left and right sides but significantly larger in males than in females. The mean width of the PLR was 4.62 ± 1.74 mm and it had a significant negative correlation with the thickness of the medial bony wall of the PLR.

CONCLUSION

A large individual variation exists in the anatomy of PLR, including its prevalence and dimensions of its medial bony wall. When considering the intranasal endoscopic prelacrimal recess approach, the surgeons should carefully evaluate the anatomical structure of the PLR preoperatively so as to minimize the risks of surgical complications.

Extended endoscopic approaches to the maxillary sinus

OBJECTIVES

Treatment of inflammatory and neoplastic disease in the maxillary sinus, pterygopalatine and infratemporal fossae requires appropriate surgical exposure. As modern rhinology evolves, so do the techniques available. This paper reviews extended endoscopic approaches to the maxillary sinus and the evidence supporting each technique.

METHODS

A literature search of the Ovid Medline and PubMed databases was performed using appropriate key words relating to endoscopic approaches to the maxillary sinus.

RESULTS

Mega-antrostomy and medial maxillectomy have a role in the surgical treatment of refractory inflammatory disease and sinonasal neoplasms. The pre-lacrimal fossa approach provides excellent access but can be limited because of anatomical variations. Both the transseptal and endoscopic Denker's approaches were reviewed; these appear to be associated with morbidity, without any significant increase in exposure over the afore-described approaches.

CONCLUSION

A range of extended endoscopic approaches to the maxillary sinus exist, each with its own anatomical limitations and potential complications.

The Anterolateral Triangle: Implications for a Transnasal Prelacrimal Approach to the Floor of the Middle Cranial Fossa

Background

The anterolateral triangle enclosed by the foramen rotundum and foramen ovale constitutes part of the floor of the middle cranial fossa (MCF).

Objective

To assess the feasibility of a transnasal prelacrimal approach for accessing the floor of MCF via an anterolateral triangle corridor and to determine the extent of maximal exposure while safeguarding neurovascular structures.

Methods

A transnasal prelacrimal approach was performed in 5 cadaveric specimens (10 sides). Following the identification of foramen rotundum and foramen ovale, the bony ridge between 2 was drilled to expose the MCF. The temporal lobe dura was then elevated laterally, and the distances from foramen ovale to the respective borders of the area of the MCF window were measured using a surgical navigation device.

Results

The MCF was exposed with a 0° scope in all specimens also exposing significant landmarks including the middle meningeal artery, greater superficial petrosal nerve, superior petrous sinus, and arcuate eminence. Average distances from foramen ovale to the anterior, posterior, and lateral exposed borders were 22.86 ± 1.87 mm, 27.24 ± 0.94 mm, and 24.23 ± 1.61 mm, respectively. The average area of exposed MCF window was 554.12 ± 60.22 mm2. Preservation of vidian nerve, greater palatine nerve, lateral nasal wall, and nasolacrimal duct was possible in all 10 sides.

Conclusion

It is feasible to access the floor of MCF via an endoscopic transnasal prelacrimal approach with seemingly low risk.

Endoscopic transnasal transmaxillary approach to the upper parapharyngeal space and the skull base

Purpose

Treatment of tumors arising in the upper parapharyngeal space (PPS) or the floor of the middle cranial fossa is challenging. This study aims to present anatomical landmarks for a combined endoscopic transnasal and anterior transmaxillary approach to the upper PPS and the floor of the middle cranial fossa and to further evaluate their clinical application.

Methods

Dissection of the upper PPS using a combined endoscopic endonasal transpterygoid and anterior transmaxillary approach was performed in six cadaveric heads. Surgical landmarks associated with the approach were defined. The defined approach was applied in patients with tumors involving the upper PPS.

Results

The medial pterygoid muscle, tensor veli palatini muscle and levator veli palatini muscle were key landmarks of the approach into the upper PPS. The lateral pterygoid plate, foramen ovale and mandibular nerve were important anatomical landmarks for exposing the parapharyngeal segment of the internal carotid artery through a combined endoscopic transnasal and anterior transmaxillary approach. The combined approach provided a better view of the upper PPS and middle skull base, allowing for effective bimanual techniques and bleeding control. Application of the anterior transmaxillary approach also provided a better view of the inferior limits of the upper PPS and facilitated control of the internal carotid artery.

Conclusions

Improving the knowledge of the endoscopic anatomy of the upper PPS allowed us to achieve an optimal approach to tumors arising in the upper PPS. The combined endoscopic transnasal and anterior transmaxillary approach is a minimally invasive alternative approach to the upper PPS.

Endoscopic prelacrimal approach to lateral recess of sphenoid sinus: feasibility study

BACKGROUND

Various pathologies, including cerebrospinal fluid leaks and meningoencephaloceles, may arise in the lateral recess of the sphenoid sinus (LRSS), which may be accessed via an endonasal transpterygoid approach. The objective of this study was to evaluate the feasibility of accessing the LRSS via an endoscopic prelacrimal approach. Furthermore, we hypothesized that this approach may protect the pterygopalatine ganglion and vidian nerve.

METHODS

Five cadaveric heads (9 sides) with a well-pneumatized LRSS were identified and an endonasal prelacrimal approach was performed. The infraorbital nerve, at the orbital floor, served as a critical landmark. After identification of the foramen rotundum at the pterygoid base, the vascular compartment of the pterygopalatine fossa and the pterygopalatine ganglion were displaced inferomedially and superomedially, respectively. Drilling of the bone inferomedial to the foramen rotundum allowed entry into the LRSS.

RESULTS

The average distances from the prelacrimal window to the pterygoid base and the posterior wall of the LRSS were 6.22 ± 0.39 cm and 7.16 ± 0.50 cm, respectively. The average areas of the bony prelacrimal window and pterygoid base window were 4.33 ± 0.32 cm² and 0.73 ± 0.10 cm² , respectively. The LRSS could be accessed using a 0-degree endoscope, and pterygopalatine neurovascular structures, including the pterygopalatine ganglion and vidian nerve, could be preserved on all 9 sides.

CONCLUSION

Our findings suggest that an endonasal prelacrimal approach provides a reasonable alternative to access the LRSS while preserving the vidian nerve and pterygopalatine ganglion.

Assessment of the prelacrimal recess in maxillary sinus in different sex and age groups using cone beam computed tomography (CBCT)

BACKGROUND

The intranasal endoscopic prelacrimal recess approach (PLRA) to the maxillary sinus (MS) has been reported to treat many MS and skull base diseases. However, previous studies revealed that the width of the prelacrimal recess (PLR) shows a large individual variation. The purpose of this study was to ascertain the prevalence of the PLR in MS according to gender and age.

METHODS

A series of 701 maxillofacial cone beam computed tomography (CBCT) scans from adult patients were analyzed retrospectively. Patients were divided into five age groups (18-24 years, 25-34 years, 35-44 years, 45-54 years, and ≥ 55 years) and by sex. The frequencies of occurrence of the PLR in the MS were calculated and compared.

RESULTS

According to the findings obtained from our study, PLR was present in 81.5% of maxillary sinuses. No differences were found when the data distributions of right and left sides were compared. For individuals, the right and left sides were not always symmetrical. The probability of PLR was lesser among women than among men, but this differences was not significant. Another finding of our study was that the percentage of PLR decreased with increasing age among patients aged < 55 years, however, increased again among patients aged ≥ 55 years.

CONCLUSION

The anatomy of PLR varies among individuals. Careful analysis of individual anatomical structure characteristic is recommended when considering intranasal endoscopic PLRA to the MS. Besides, the age variation of PLR should be considered in order to avoid complications.

Anatomical Variants of the Infraorbital Canal: Implications for the Prelacrimal Approach to the Orbital Floor

Background

The infraorbital nerve (ION) and its canal are important landmarks during surgical approaches to the orbital floor and pterygopalatine fossa. However, variations in the anatomy of the infraorbital canal and its corresponding neurovascular bundle may impact the access.

Objective

To investigate anatomic variants of the infraorbital canal from a prelacrimal endoscopic perspective and to explore the impact of these variants on exposing the lateral orbital floor.

Methods

Ten cadaveric specimens (20 sides) were dissected through an endonasal prelacrimal approach. Anatomic variants of the ION including location, branching pattern, and relationship to the infraorbital artery were assessed. The need for ION transposition to increase exposure of the lateral orbital floor was also investigated.

Results

Incidence of previously described Types 1, 2, and 3 ION variants were 30.0%, 60.0%, and 10.0%, respectively. Although the orbital floor could be directly accessed in Type 1 and Type 3 IONs, transposition of the ION was necessary to expose the lateral orbital floor in 5 of 12 sides (42%) for Type 2 ION. Bony dehiscence of the orbital floor was identified in 8 of 20 sides (40%) and branching of the ION in 2 of 20 sides (10%).

Conclusion

Anatomic variations of the infraorbital canal impact surgical exposure of the orbital floor via a prelacrimal approach. Type 1 and Type 3 ION variants allow a direct exposure of the entire orbital floor. A Type 2 ION may require transposition of the nerve to adequately expose the lateral orbital floor.

Adjunctive techniques to improve access of the endoscopic prelacrimal recess approach

OBJECTIVES

To determine whether adjunctive surgical techniques could improve access of instruments provided by the endoscopic prelacrimal recess approach to the anatomical boundaries of the maxillary sinus, and pterygopalatine and infratemporal fossa.

METHODS

Ten fresh-frozen adult cadaver heads were utilized. The anatomical areas of interest were fixed, bony boundaries of the maxillary sinus, infratemporal fossa, and pterygopalatine fossa: alveolar recess (AR), zygomatic recess (ZR), perpendicular plate of the palatine bone (PB), ascending ramus of mandible (RM), floor of the orbit medial and lateral to infraorbital nerve (M-ION and L-ION, respectively). Access to the areas were compared using standard sinus surgery instruments (straight and 45° forceps) introduced via the prelacrimal recess approach, trans-septal window and canine fossa puncture.

RESULTS

The prelacrimal recess approach successfully provided access to the PB and M-ION in >90% of dissections when using both the straight and 45° forceps. With the straight forceps, the ability to successfully access to the AR and ZR was the lowest at 50% and 35% respectively, although improving to 75% and 60% respectively with the 45° forceps. Access to the AR, ZR, and L-ION improved significantly when the 45° forceps was introduced through the trans-septal window. Frequency of access to the RM when either instruments when introduced through the canine fossa puncture was no greater than 60% of the dissections.

CONCLUSIONS

The addition of a small trans-septal window for instruments significantly improved access of the prelacrimal recess approach especially to the orbital floor, lateral margins of the maxillary sinus, and retromaxillary space.

LEVEL OF EVIDENCE

4 Laryngoscope, 130: 1857-1863, 2020.

Prelacrimal approach for nasolacrimal duct excision in the management of lacrimal system tumours

Purpose: To report a case of a lacrimal sac tumour and describe a prelacrimal approach to the maxillary sinus to excise the nasolacrimal duct in its management. To our knowledge, this approach has not been adapted to remove the nasolacrimal duct for the management of pathological processes involving the nasolacrimal system. Methods: A 58-year-old female patient presented with a 6-month history of epiphora. A lacrimal sac mass was identified, and a biopsy revealed squamous cell carcinoma. Surgical excision was performed via a combined external and endoscopic prelacrimal approach. Results: A prelacrimal approach to the maxillary sinus to excise the nasolacrimal duct in combination with an external approach facilitated an en-bloc excision of the nasolacrimal apparatus. This allowed preservation on the entire inferior turbinate following reconstitution of the lateral nasal wall at the completion of the procedure. Conclusion: The endoscopic endonasal prelacrimal approach to the maxillary sinus is a useful method to approach and excise the nasolacrimal duct in the management of nasolacrimal pathology.

Anterior maxillary wall and lacrimal duct relationship in Orientals: CT analysis for prelacrimal access to the maxillary sinus

BACKGROUND

The pre-lacrimal window approach (PLWA) is a promising technique in approaching lesions of the anterior wall and floor of the maxillary sinus. Simmen et al. previously reported that this approach is feasible in only 2/3 of their patients. This percentage appears to be lower than that of our local (mainly Chinese) population based on our clinical experience. Our study aims to measure the distance between the anterior maxillary wall and lacrimal duct in ethnic Chinese. A higher incidence of sphenoid-ethmoidal cells has been reported in Orientals. We postulate that there is also a higher incidence of wider pre-lacrimal recesses in Orientals thus making the PLWA more feasible to perform in Orientals.

METHODS

100 consecutive sinus CT scans of adult patients with various rhinologic diseases that did not distort the bony anatomy of the maxilla were reviewed (2 sides each). The distance between the anterior maxillary wall and the anterior border of the lacrimal duct was measured in 200 sides. We have adopted the methodology of measurements previously published by Simmen et al.  This is so that we could compare between Oriental and Occidental paranasal sinuses.

RESULTS

A distance of more than 7 mm was found in 39.5% of our subjects and a distance of > 3-7 mm was seen in 53.5%. In 6.5% of our subjects we found a prelacrimal recess < 3 mm.

CONCLUSION

The PLWA could have been performed without removal of the bony lacrimal canal in 39.5% of our subjects ( > 7 mm). Good access to the anterior maxilla wall could also have been possible for 53.5% with sub-periosteal removal of the bony lacrimal canal and medial maxillary wall. Thus, the PLWA would have been feasible for 93% of our subjects. These percentages are significantly higher than Simmen's study of 68.5% in an Occidental population.

Swinging inferior turbinate approach to the nasolacrimal duct

Purpose: To report a case of a lacrimal sac tumour identified at the time of endoscopic dacryocystorhinostomy and describe a swinging inferior turbinate approach to the nasolacrimal duct (NLD) to facilitate an en-bloc excision of the lacrimal drainage apparatus.Methods: An 88-year-old male presented with a 6-month history of epiphora and mucocele. Endonasal DCR was performed for nasolacrimal duct obstruction (NLDO). Intraoperatively, a biopsy was performed of abnormal appearing lacrimal sac mucosa, following opening of the lacrimal sac. Subsequent definitive management was performed via a combined external and endoscopic approach using a swinging inferior turbinate approach to the NLD to facilitate an en-bloc excision of the lacrimal drainage apparatus, without removal of the bony medial wall of the maxillary sinus.Results: The excised lacrimal drainage showed insitu and invasive squamous cell carcinoma of the canaliculi and lacrimal sac with focal divergent neuroendocrine and sebaceous differentiation. There was no local tumour recurrence or metastatic spread at 3 months of follow-up.Conclusions: We describe a swinging inferior turbinate approach to the NLD to facilitate an en-bloc excision of the lacrimal drainage apparatus, without entering the maxillary sinus. We believe this modified technique is a useful option to consider in the management of tumours of the lacrimal drainage apparatus.

Endoscopic Two-port Technique for Infratemporal Fossa Tumors: Using Prelacrimal Medial Maxillectomy and Caldwell-Luc Approach

BACKGROUND

Endoscopic endonasal approach to infratemporal fossa (ITF) had gained popularity. However, the inferior turbinate and/or lacrimal duct are often removed when performing endoscopic medial maxillectomy for ITF approach and there were potential risk of empty nose syndrome or epiphora. Although endoscopic prelacrimal recess approach (EPRA) had been introduced to avoid these complications, there were some limitations associated with surgical freedom. The objective was to report the two-port endoscopic technique using both prelacrimal recess and antral window as a means to preserve inferior turbinate and lacrimal duct while facilitating instrument availability during ITF tumor resection.

METHODS

We retrospectively reviewed three patients between September 2016 and May 2018 who were treated with this modified two port technique for ITF tumors.

RESULTS

There was one case of trigeminal schwannoma originating in the mandibular nerve, one recurrent meningioma, and one paraganglioma. This two-port technique was not initially scheduled in these three cases but decided during surgery because tumors were extensively attached to surrounding muscles and have profuse bleeding. After tumor resection, sinonasal anatomy such as inferior turbinate or lacrimal duct was well preserved.

CONCLUSIONS

We propose a hybrid endoscopic surgical procedure for ITF tumors using both EPRA and transantral window. It allows the surgeons to have an advantage of utilizing an adequate working space by bimanual technique through different two ports while preserving normal sinonasal structures.

Neuroendoscopic Resection of Trigeminal Schwannoma in the Pterygopalatine/Infratemporal Fossa via the Transnasal Perpendicular Plate Palatine Bone or Transnasal Maxillary Sinus Approach

BACKGROUND

Both the pterygopalatine fossa (PPF) and the infratemporal fossa (ITF) lie outside the midline of the skull base. Lesions in the PPF or ITF include trigeminal schwannoma (trigeminal schwannoma, TS), which originates from the second or third branch of the trigeminal nerve (maxillary nerve or mandibular nerve). Due to their typically deep anatomic location, lesions in the PPF or ITF can be difficult to treat using traditional surgical approaches. In recent years, because of their advantages, which include the fact that they allow the problem to be observed close up, neuroendoscopic techniques are increasingly being applied in skull base surgery, especially in treatment of lesions around the midline of the base of the skull. This study aims to 1) evaluate the neuroendoscopic treatment of lesions in PPF or ITF via the transnasal palate bone perpendicular plate or transnasal maxillary sinus approach and 2) analyze the clinical significance of this approach.

METHODS

We retrospectively analyzed 3 cases of PPF TSs and 1 case of ITF TS treated between January 2015 and May 2017. All of the cases underwent neuroendoscopic resection of TSs located in the PPF via the nasal perpendicular plate palatine bone (or nasal maxillary sinus) approach.

RESULTS

Two cases of PPF TSs were characterized by a thin palate bone perpendicular plate due to oppressed absorption of the tumor. Therefore the endoscopic transnasal palate bone perpendicular plate approach was employed. Additionally, 1 case of PPF TSs and 1 case of ITF TS were resected via the transnasal maxillary sinus approach. All 4 patients received total resection under endoscopy and recovered well after their respective operations without cerebrospinal fluid leakage, although 1 patient experienced postoperative dry eye symptoms and 1 other patient showed no improvement in facial numbness before and after the operation.

CONCLUSIONS

Neuroendoscopic surgery performed via the transnasal perpendicular plate palatine bone or transnasal maxillary sinus approach has its own unique advantages in removing TSs in PPF and in ITF: Notably, the tumor can be exposed and dealt with under direct vision, which prevents damage to important structures, such as the internal carotid and maxillary nerves, while at the same time helping to achieve total removal of TSs. Furthermore, by adopting this approach versus traditional skull base surgery, postoperative trauma can be reduced significantly, which should be advocated for in this time of minimal invasive surgery.

Dimensions of the medial wall of the prelacrimal recess

BACKGROUND

Addressing anterior maxillary sinus pathology endoscopically that is inaccessible with an endoscopic modified medial maxillectomy requires either a prelacrimal approach (PLA) or an endoscopic Denker's approach (EDA). The PLA involves removing the medial wall of the prelacrimal recess (PLR), which is the bone between the pyriform aperture (PA) and nasolacrimal duct (NLD), from nasal floor to orbital floor. The PLA preserves the inferior turbinate and NLD, whereas both are sacrificed during an EDA. The purpose of this computed tomography (CT)-based study was to determine the anteroposterior and superoinferior dimensions of the medial wall of the PLR.

METHODS

One hundred thirty-one triplanar sinus CT scans of patients with various rhinologic diseases, but with intact bony PLR walls, were reviewed to assess dimensions of the medial wall of the PLR. The anteroposterior distances from the PA to the inferior-most, middle, and superior-most aspects of the NLD were measured. The height from the nasal floor to orbital floor was also measured. Combining left and right sides, there were 262 measurements.

RESULTS

The anteroposterior distances between the PA and the NLD were as follows: inferior: mean, 8.4 mm (standard error [SE], 0.2; range, 1.9-14.2); middle: mean, 7.6 mm (SE, 0.2; range, 0-13.6); and superior: mean, 5.5 mm (SE, 2.5; range, 0-11.9). The mean height of the medial wall of the PLR was 26.5 mm (SE, 0.2; range, 18.5-39.9).

CONCLUSION

The anteroposterior and superoinferior dimensions of the medial wall of the PLR are variable, with the anteroposterior dimension being widest inferiorly. Its dimensions should be evaluated preoperatively when considering endoscopic approaches to or through the anterior maxillary sinus.