Endoscopic Endonasal Transpterygoid Approach Research Articles

Morphometric Comparison of Endoscopic Endonasal Transpterygoid and Precaruncular Contralateral Medial Transorbital Approaches to Sphenoid Sinus Lateral Recess.

The endoscopic endonasal transpterygoid approach (TPA), minimally invasive compared with the sublabial transmaxillary and transcranial approaches, still accounts for morbidity in benign lateral recess of sphenoid sinus (LRSS) pathologies. Others have suggested an alternative route to the LRSS, the endoscopic contralateral medial transorbital approach (cMTO). However, no quantitative evidence exists to support the clinical application of this approach. This cadaveric study, in a controlled laboratory setting, provides a morphometric comparison of the TPA and cMTO for accessing the LRSS. The study also details the anatomy and technical nuances for optimizing the cMTO corridor. Ten fresh preinjected human cadaveric specimens (20 sides) were dissected with neuronavigation, completing endoscopic cMTO and TPA on each side. Four parameters-working distance to lateral recess, surgical exposure area, angle of attack (AoA), and surgical freedom-were measured for each approach. Relevant osteological measurements in 10 dried human skulls were recorded. The mean distance from the superior margin of the lacrimal sac impression to the inferior margin of the trochlear fossa was 10.29 ± 1.13 mm, and that from the anterior ethmoidal artery foramina to the posterior lacrimal crest was 9.63 ± 1.23 mm. The mean exposure area around the LRSS was significantly higher in TPA (614.09 ± 40.38 mm2) than in cMTO (391.19 ± 59.01 mm2, P = .001). The mean AoA was 9.83° and 10.24° in the cMTO and TPA, respectively, in the craniocaudal direction (P = .529). In the horizontal plane, it was 9.29° and 10.76° (P = .012). There was no significant difference in surgical freedom between the cMTO and TPA (804.61 and 806.05 mm3, respectively; P = .993). Although comparatively limited exposure area, the cMTO approach has a similar AoA and surgical freedom as TPA and offers better visualization and ergonomic advantages. cMTO provides a feasible, less morbid, multiport technique for benign sphenoid sinus lateral recess pathologies.

Endoscopic endonasal transpterygoid nasopharyngectomy: Anatomical considerations and technical note.

The study was designed to identify new landmarks in the parapharyngeal segment of the internal carotid artery (ICA) for nasopharyngectomy and describe a surgical procedure of endoscopic endonasal transpterygoid nasopharyngectomy (EETPN). Four cadaveric specimens were injected with colored silicone and subjected to CT scanning before dissection. The nasopharyngeal skull base was exposed using the endoscopic endonasal transpterygoid approach. The clinical data of four patients with nasopharyngeal malignances who underwent EETPN were reviewed. The lateral edge of the longus capitis muscle medially; the foramen lacerum, petrous apex spine and the stump of the levator veli palatini muscle superior laterally; and the upper parapharyngeal ICA laterally constitute the ICA-longus capitis muscle-petrous apex spine triangle which was a novel landmark for the upper parapharyngeal segment of the ICA. The ICA-longus capitis muscle-petrous apex spine triangle are important landmarks of the upper parapharyngeal segment of the ICA.

Quantitative Anatomical Comparison of Surgical Approaches to Meckel's Cave.

Meckel's cave is a challenging surgical target due to its deep location and proximity to vital neurovascular structures. Surgeons have developed various microsurgical transcranial approaches (MTAs) to access it, but there is no consensus on the best method. Newer endoscopic approaches have also emerged. This study seeks to quantitatively compare these surgical approaches to Meckel's cave, offering insights into surgical volumes and exposure areas. Fifteen surgical approaches were performed bilaterally in six specimens, including the pterional approach (PTA), fronto-temporal-orbito-zygomatic approach (FTOZA), subtemporal approach (STA), Kawase approach (KWA), retrosigmoid approach (RSA), retrosigmoid approach with suprameatal extension (RSAS), endoscopic endonasal transpterygoid approach (EETPA), inferolateral transorbital approach (ILTEA) and superior eyelid approach (SEYA). All the MTAs were performed both with 10 mm and 15 mm of brain retraction, to consider different percentages of surface exposure. A dedicated navigation system was used to quantify the surgical working volumes and exposure of different areas of Meckel's cave (ApproachViewer, part of GTx-Eyes II, University Health Network, Toronto, Canada). Microsurgical transcranial approaches were quantified with two different degrees of brain retraction (10 mm and 15 mm). Statistical analysis was performed using a mixed linear model with bootstrap resampling. The RSAS with 15 mm of retraction offered the maximum exposure of the trigeminal stem (TS). If compared to the KWA, the RSA exposed more of the TS (69% vs. 46%; p = 0.01). The EETPA and ILTEA exposed the Gasserian ganglion (GG) mainly in the anteromedial portion, but with a significant 20% gain in exposure provided by the EETPA compared to ILTEA (42% vs. 22%; p = 0.06). The STA with 15 mm of retraction offered the maximum exposure of the GG, with a significant gain in exposure compared to the STA with 10 mm of retraction (50% vs. 35%; p = 0.03). The medial part of the three trigeminal branches was mainly exposed by the EETPA, particularly for the ophthalmic (66%) and maxillary (83%) nerves. The EETPA offered the maximum exposure of the medial part of the mandibular nerve, with a significant gain in exposure compared to the ILTEA (42% vs. 11%; p = 0.01) and the SEY (42% vs. 2%; p = 0.01). The FTOZA offered the maximum exposure of the lateral part of the ophthalmic nerve, with a significant gain of 67% (p = 0.03) and 48% (p = 0.04) in exposure compared to the PTA and STA, respectively. The STA with 15 mm of retraction offered the maximum exposure of the lateral part of the maxillary nerve, with a significant gain in exposure compared to the STA with 10 mm of retraction (58% vs. 45%; p = 0.04). The STA with 15 mm of retraction provided a significant exposure gain of 23% for the lateral part of the mandibular nerve compared to FTOZA with 15 mm of retraction (p = 0.03). The endoscopic approaches, through the endonasal and transorbital routes, can provide adequate exposure of Meckel's cave, especially for its more medial portions, bypassing the impediment of major neurovascular structures and significant brain retraction. As far as the most lateral portion of Meckel's cave, MTA approaches still seem to be the gold standard in obtaining optimal exposure and adequate surgical volumes.

Endoscopic Endonasal Transpterygoid Approach: Technical Lessons.

The endoscopic endonasal transpterygoid approach (EETPA) provides direct access to the petrous apex, lateral clivus, inferior cavernous sinus compartment, jugular foramen, and infratemporal fossa. 1,2 In the coronal plane, it provides exposure far beyond a traditional sphenoidotomy. The pterygoid process of the sphenoid bone forms the junction between the body and greater sphenoid wing before bifurcating because it descends into medial and lateral plates. The key to this exposure lies in the region's bony foramina: the palatovaginal canal, vidian canal, and foramen rotundum. 3. After performing a maxillary antrostomy, stepwise exposure of these foramina leads to the pterygopalatine fossa. The sphenopalatine artery is cauterized as it becomes the posterior septal artery at the sphenopalatine foramen, and the maxillary sinus' posterior wall is opened to expose the pterygopalatine fossa. After mobilizing and retracting the contents of the pterygopalatine fossa, the pterygoid process is removed, improving access in the coronal plane. 4. Vidian neurectomy causes decreased or absent lacrimation. Injury to the maxillary nerve or its branches results in facial, palatal, or odontogenic anesthesia or neuralgia. In addition, the EEPTA precludes the ability to raise an ipsilateral nasal septal flap, making it crucial to plan reconstruction preoperatively. 4,5. There are 5 variants of the EEPTA: extended pterygopalatine fossa, lateral recess of the sphenoid sinus, petrous apex, infratemporal fossa and petrous carotid artery, and middle and posterior skull base. 5The patient consented to the procedure.Images in the video used with permission as follows: images at 0:33 and 1:15 reused from Bozkurt et al, 3 © Georg Thieme Verlag KG; image at 0:39 from Prosser et al, 5 © John Wiley and Sons; images at 0:54, 9:03, and 9:38 from Kasemsiri et al, 1 © John Wiley and Sons; images at 1:07 and 9:44 from Falcon et al, 2 © John Wiley and Sons; image at 1:15 from Sandu et al, 4 © Springer Nature.

Anatomical Step-by-Step Dissection of Complex Skull Base Approaches for Trainees: Surgical Anatomy of the Endoscopic Endonasal and Endoscopic-Assisted Transmaxillary Transpterygoid Approaches

Abstract Introduction The endoscopic endonasal transpterygoid approach (EETPA) with or without the addition of the endoscopic-assisted sublabial anterior transmaxillary approach (ESTA) has become increasingly utilized for lesions posterior to the pterygopalatine fossa (PPF), including infratemporal fossa (ITF), lateral recess of the sphenoid sinus, Meckel's cave, petrous apex, and parapharyngeal space. The main goal of this study is to develop an educational resource to learn the steps of the EETPA for trainees. Methods EETPA and ESTA were performed in 12 specimens by neurosurgery trainees, under supervision from the senior authors. One EETPA and one ESTA were performed on each specimen on opposite sides. Dissections were supplemented with representative cases. Results After a wide unilateral sphenoidotomy, ethmoidectomy, and partial medial maxillectomy, the anteromedial bone limits of the PPF were identified and drilled out. The pterygoid progress was modularly removed. By enlarging the opening of the posterior and lateral walls of the maxillary sinus through EETPA and ESTA, respectively, the neurovascular and muscular compartments of the PPF and ITF were better identified. The EETPA opens direct corridors to the PPF, medial ITF, middle cranial fossa, cavernous sinus, Meckel's cave, petrous apex, and internal carotid artery. If a more lateral exposure of the ITF is needed, the ESTA is an appropriate addition. Conclusion Despite the steep learning curve of the EETPA, granular knowledge of its surgical anatomy and basic surgical steps are vital for those advancing their learning in complex endoscopic approaches to the ventral skull base when expanding the approach laterally in the coronal plane.

Endoscopic Endonasal Transpterygoid Approach for Resection of Carotid Sympathetic Plexus Schwannomas: A Cadaveric Stepwise Dissection, Technical Nuances and Surgical Outcomes

Carotid sympathetic plexus (CSP) schwannomas are rare brain tumors located in a complex site around the cavernous sinus and carotid canal in the petrous bone. This study describes 3 cases of CSP schwannomas that underwent surgical removal of the tumor through an endoscopic endonasal transpterygoid approach. Between 2016 and 2021, 3 cases of CSP schwannomas were treated using an endoscopic endonasal transpterygoid approach. Preoperative tumor size, preoperative and postoperative symptoms, internal carotid artery (ICA) displacement, extent of tumor resection, intraoperative findings showing tumor origin, and surgical complications were evaluated in all patients. Two tumors were in the petrous region, and the other one was in both the petrous and cavernous regions. The median tumor diameter was 41.3mm. In the 3 cases, the ICA was displaced to the superolateral side, the anterolateral side, and the posterior side, respectively. Near-total resection was achieved in all 3 cases via an endoscopic endonasal transpterygoid approach. There were no endonasal postoperative complications, and the cranial nerve disability improved in all 3 patients at 1-year follow-up. The surgical technique for CPS schwannoma using an endoscopic endonasal transpterygoid approach may be a viable option because endoscopy has been proven to offer better intraoperative visualization and reduce postoperative discomfort for patients. Tumors located medial and inferior to the ICA pars cavernous sinus or anterior, inferior, and medial to the paraclival ICA are ideal candidates for surgery using this endoscopic approach.

A Giant Schwannoma Extending from Medial Portion of Middle Cranial Fossa to Parapharyngeal Space and Deep Parotid Space.

Trigeminal schwannomas are rare tumours comprising 0.2% of all intracranial tumours and 0.5% of all head and neck tumours. Patients with trigeminal schwannomas presented with facial hypoesthesia and pain. We presented a case with left bulging oropharynx. The CT scan showed a 3.8x2.6x4.9cm left parapharyngeal tumour compressed to the oropharynx and middle cranial fossa. We performed 3 ways in two times of operation to excise the whole tumour. We chose the transoral approach for parapharyngeal space, trans-parotid approach for deep parotid part and the endoscopic endonasal trans-pterygoid approach and trans-maxillary with Canine fossa trephination for intracranial lesions. The pathology showed schwannoma. A huge schwannoma extended from intracranial to several spaces is difficult to resect just by one approach. We should separate the tumour to several parts by clinical image before the operation and design a plan to remove the whole tumour in different approach. The different space of tumour involvement had several ways to access. We needed to choose the less harm but with better surgical field.

Quantitative Anatomic Comparison of Microsurgical Transcranial, Endoscopic Endonasal, and Transorbital Approaches to the Spheno-Orbital Region.

The spheno-orbital region (SOR) is a complex anatomic area that can be accessed with different surgical approaches. To quantitatively compare, in a preclinical setting, microsurgical transcranial approaches (MTAs), endoscopic endonasal transpterygoid approach (EEA), and endoscopic transorbital approaches (ETOAs) to the SOR. These approaches were performed in 5 specimens: EEA, ETOAs (superior eyelid and inferolateral), anterolateral MTAs (supraorbital, minipterional, pterional, pterional-transzygomatic, and frontotemporal-orbitozygomatic), and lateral MTAs (subtemporal and subtemporal transzygomatic). All specimens underwent high-resolution computed tomography; an optic neuronavigation system with dedicated software was used to quantify working volume and exposed area for each approach. Mixed linear models with random intercepts were used for statistical analyses. Anterolateral MTAs offer a direct route to the greater wings (GWs) and lesser wings (LWs); only they guarantee exposure of the anterior clinoid. Lateral MTAs provide access to a large area corresponding to the GW, up to the superior orbital fissure (SOF) anteriorly and the foramen rotundum medially. ETOAs also access the GW, close to the lateral portion of SOF, but with a different angle of view as compared to lateral MTAs. Access to deep and medial structures, such as the lamina papyracea and the medial SOF, is offered only by EEA, which exposes the LW and GW only to a limited extent. This is the first study that offers a quantitative comparison of the most used approaches to SOR. A detailed knowledge of their advantages and limitations is paramount to choose the ideal one, or their combination, in the clinical setting.

Plasma Ablation−Assisted Endoscopic Endonasal Transpterygoid Approach to Sphenoid Lateral Recess Cerebrospinal Fluid Leaks: Technique and Outcome

Management of sphenoid lateral recess (SLR) cerebrospinal fluid (CSF) leaks present a challenge because of the location and requiring complete visualization of the defect for a successful repair. The endoscopic endonasal transpterygoid approach (EETPA) is considered the gold standard in addressing these defects. We lay out our experience in implementing this approach with plasma ablation. This is a case series of 11 diagnosed patients of SLR CSF leaks who underwent plasma ablation-assisted EETPA repair by a single surgeon between 2011 and 2020 at our institution. Outcomes in terms of surgical field grade on the Wormald 11-point grading scale, postoperative complications, healing on nasal endoscopy and imaging, and surgical success rate were assessed. The etiology was spontaneous leak in 10 (90.9%) patients and secondary to temporal lobe abscess and/or meningitis in one (9.09%). Three (27%) patients were previously operated elsewhere by the transsphenoidal route, which we reoperated by this technique. As per Wormald grading, grade 1 field in 3 (27.27%), grade 2 in 6 (54.5%), and grade 3 in 2 cases (18.18%) were noted. Complications occurred in 3 patients (27%) in the form of dry eye (9%), meningitis (9%), and transient CSF rhinorrhea in the immediate postoperative period (9%). Repair sites were well healed on follow-up nasal endoscopy and imaging. The surgical success rate was 100%. Plasma ablation-assisted EETPA allows for a uninostril approach to the SLR, easy accessibility, and better visualization with a bloodless field, which allows appropriate repair, thus minimizing complications and preventing recurrence.

Combined Anterior Transmaxillary (Caldwell-Luc) With an Endoscopic Endonasal Transpterygoid Approach for Resection of a Large Juvenile Nasopharyngeal Angiofibroma: 2-Dimensional Operative Video

Juvenile nasopharyngeal angiofibroma (JNA) is a highly vascular benign tumor that originates in the sphenopalatine foramen and often spreads to adjacent compartments.1 Microsurgical resection with preoperative embolization remains the treatment of choice.2 We present a case of a large JNA involving multiple compartments. The patient is a 20-yr-old male who presented with long-term right nasal congestion. The MRI demonstrated a large enhancing mass that extended from the right nasal cavity and nasopharynx into the right pterygopalatine fossa (PPF), infratemporal fossa (ITF), and parapharyngeal space. Preoperative angiogram for embolization showed a highly vascular tumor with blood supply mainly from the internal maxillary artery and about 10% from a persistent mandibular branch of the internal carotid artery. Based on the UPMC JNA staging system, this tumor was a stage IV.2 A combined anterior transmaxillary (Caldwell-Luc) with an endoscopic endonasal transpterygoid approach was performed. The addition of the anterior transmaxillary approach increases the surgical freedom for traditional bipolar devices and improves the view and trajectory to more lateral structures like the PPF and ITF.3 Gross total resection was achieved without complications. The patient was discharged home with a partial V2 numbness (right superior gum) that improved with time. The endoscopic endonasal approach is a safe and effective technique even for large JNA. A multidisciplinary team consisting of an interventional radiologist, a skull base neurosurgeon, and an otorhinolaryngologist with expertise in endoscopic surgery may play a role for optimal surgical results. The patient consented for the procedure and for the video production.

Management of Cerebrospinal Fluid Rhinorrhea in the Sphenoid Sinus Lateral Recess Through an Endoscopic Endonasal Transpterygoid Approach With Obliteration of the Lateral Recess

Cerebrospinal fluid rhinorrhea in the sphenoid sinus lateral recess is a rare occurrence and poses unique challenges due to limited surgical access for surgical repair. To report our experience of surgical repair of cerebrospinal fluid rhinorrhea in the sphenoid sinus lateral recess through an endoscopic endonasal transpterygoid approach with obliteration of the lateral recess. To evaluate the efficiency of this surgical procedure. A retrospective study. Twelve cases with cerebrospinal fluid rhinorrhea in the sphenoid sinus lateral recess were reviewed. Assisted by image-guided navigation, cerebrospinal fluid rhinorrhea was repaired through an endoscopic endonasal transpterygoid approach, with obliteration of the lateral recess. Complications and recurrence were recorded. Medical photographs were used. This surgical approach provided a relatively spacious corridor to dissect the sphenoid sinus lateral recess and do postoperative surveillance. The repair area completely healed in 3 months after surgery. Cerebrospinal fluid rhinorrhea in the sphenoid sinus lateral recess was successfully repaired on the first attempt in all cases (100%). No main complications or recurrence was observed during a mean follow-up time of 40.3 months. The endoscopic endonasal transpterygoid approach gives appropriate access for the treatment of spontaneous cerebrospinal fluid rhinorrhea in the sphenoid sinus lateral recess. Multilayer reconstruction of a skull base defect with obliteration of the lateral recess is a reliable and simple method.

Endoscopic endonasal transpterygoid approach for reduction of a lateral recess encephalocele with postoperative cerebrospinal fluid leak

The authors present an endoscopic endonasal transpterygoid approach for reduction of a lateral recess encephalocele with post-operative cerebrospinal fluid leak. A 43-year-old man presented with right-sided clear rhinorrhea for 2...

Successful endoscopic endonasal surgery for very huge trigeminal schwannomas in nasopharynx

We present a 60-year-old female diagnosed with a giant trigeminal tumor (5.2*6.4*8.2 cm) situated in the middle cranial fossa and nasopharyngeal area. The patient was operated on by endoscopic endonasal transmaxillary, transpterygoid and infratemporal approaches. Postoperatively she was stable, with no neurologic complication and no cerebrospinal fluid leakage. We review the literature on extremely large trigeminal schwannomas.

Surgical excision of trigeminal (V3) schwannoma through endoscopic transpterygoid approach

Background:Endoscopic endonasal transpterygoid (EET) approach is well suited for trigeminal schwannomas.Case Description:A 25-year-old female presented with the right hemifacial pain for 1 month. Examination revealed mild sensory loss to both touch and pain in the right V2 and V3 dermatomal distribution. On magnetic resonance imaging, a well-defined extra-axial lesion was seen in the right infratemporal fossa extending intracranially, widening the foramen ovale. Erosion of the lateral pterygoid plate was evident on computed tomography. Diagnosis of a trigeminal schwannoma was made and excision through endoscopic transnasal transpterygoid approach was planned. After adequate nasal decongestion, lateralization of the inferior turbinate followed by medialization of middle turbinate done to expose the posterior part of the lateral nasal wall. Sphenopalatine foramen was visualized and the branches of the sphenopalatine artery to turbinate were coagulated followed by partial inferior and middle turbinectomy. Next, antegrade uncinectomy, bullectomy, and middle meatal antrostomy performed. Anterior and posterior ethmoidectomy was done to gain access to the sphenoid sinus. Medial maxillectomy done, posterior maxillary sinus wall exposed and drilled to reach infratemporal fossa harboring the tumor. The lateral recess was further exposed to visualize the vidian and maxillary nerves. Palatine bone and pterygoid body along with the medial pterygoid plate were completely drilled to expose the tumor capsule, which was gently dissected off. Complete tumor excision was performed uneventfully.Conclusion:EET provides a good oncological and functional outcome. With a lesser risk of surgical morbidities, it is an excellent alternative to conventional skull base approaches to trigeminal schwannomas in the modern era.

Refining the anatomic boundaries of the endoscopic endonasal transpterygoid approach: the "VELPPHA area" concept.

The endoscopic endonasal transpterygoid route has been widely evaluated in cadavers, and it is currently used during surgery for specific diseases involving the lateral skull base. Identification of the petrous segment of the internal carotid artery (ICA) is a key step during this approach, and the vidian nerve (VN) has been described as a principal landmark for safe endonasal localization of the petrous ICA at the level of the foramen lacerum. However, the relationship of the VN to the ICA at this level is complex as well as variable and has not been described in the pertinent literature. Accordingly, the authors undertook this purely anatomical study to detail and quantify the peri-lacerum anatomy as seen via an endoscopic endonasal transpterygoid pathway. Eight human anatomical specimens (16 sides) were dissected endonasally under direct endoscopic visualization. Anatomical landmarks of the VN and the posterior end of the vidian canal (VC) during the endoscopic endonasal transpterygoid approach were described, quantitative anatomical data were compiled, and a schematic classification of the most relevant structures encountered was proposed. The endoscopic endonasal transpterygoid approach was used to describe the different anatomical structures surrounding the anterior genu of the petrous ICA. Five key anatomical structures were identified and described: the VN, the eustachian tube, the foramen lacerum, the petroclival fissure, and the pharyngobasilar fascia. These structures were specifically quantified and summarized in a schematic acronym-VELPPHA-to describe the area. The VELPPHA area is a dense fibrocartilaginous space around the inferior compartment of the foramen lacerum that can be reached by following the VC posteriorly; this area represents the posterior limits of the transpterygoid approach and, of utmost importance, no neurovascular structures were observed through the VELPPHA area in this study, indicating that it should be a safe zone for surgery in the posterior end of the endoscopic endonasal transpterygoid approach. The VELPPHA area represents the posterior limits of the endoscopic endonasal transpterygoid approach. Early identification of this area can enhance the safety of the endoscopic endonasal transpterygoid approach expanded to the lateral aspect of the skull base, especially when treating patients with poorly pneumatized sphenoid sinuses.

Contrasting Surgical Management of CSF Leak from Lateral Recess of Sphenoid Sinus and Its Surgical Outcomes: Our Experience.

CSF leak from Lateral Recess of Sphenoid (LRS) sinus accounts for 35% of all CSF rhinorrhoea cases. There are various surgical techniques described for repair of LRS CSF leak. This study describes the experience of LRS leak repair in a tertiary care center with three different surgical techniques. Study comprises of 3 cases of LRS CSF leak that presented to J.S.S. Hospital, during the time period of July 2018-January 2019, who underwent endoscopic CSF leak repair. All three cases underwent endoscopic endonasal transpterygoid approach to the leak site. The closure technique opted for all three cases were different. For the first case free mucosal flap from ipsilateral middle turbinate was used, for the second ipsilateral nasoseptal flap (NSF) was used and contralateral NSF was used for the third. All the cases were followed up for a minimum of 3months. In all the 3 cases the CSF leak site was located in the lateral recess of Sphenoid sinus. Encephalocele was noted in two cases, which were cauterised and closure was done as planned. Crusting was more in cases that underwent closure using free mucosal flap. Healing and take up was similar for both the ipsilateral NSF and contralateral NSF. The endoscope has revolutionized the management of CSF leak from the lateral recess of sphenoid sinus. These defects can be managed efficiently using multilayer closure of defect. For large defects, the Posterior nasoseptal flaps can be used. In addition, contralateral PNSF has lower chances of being devascularized due to injury to pedicle while drilling the pterygoid plates.

Endoscopic endonasal transpterygoid transnasopharyngeal management of petroclival chondrosarcomas without medial extension.

Chondrosarcomas of the skull base are malignant tumors for which surgery is the primary therapeutic option. Gross-total resection has been demonstrated to improve survival in patients with these tumors. Chondrosarcomas arising from the petroclival synchondrosis harbor particularly unique anatomical considerations that have long been a barrier to achieving such a resection. Endoscopic endonasal transpterygoid approaches have been recently used to gain improved access to such lesions; however, these approaches have classically relied on a medial to lateral transclival trajectory, which provides limited exposure for complete resection of lateral disease. In this paper the authors describe an endoscopic endonasal transpterygoid transnasopharyngeal approach that provides comprehensive access to the petroclival region through dissection of the eustachian tube with resection of the cartilaginous torus tubarius. Of note, the authors have previously demonstrated the superior outcomes and validity of this approach relative to other cranial base techniques for petroclival chondrosarcomas. Surgical outcomes in 5 cases of chondrosarcoma without medial extension are detailed. Gross-total resection was achieved in 4 of 5 patients. Postoperative complications included transient palatal numbness in all patients and eustachian tube dysfunction due to the approach. With tympanostomy tube placement, no patient had persistent hearing loss. Overall, this approach appears to be a safe and effective technique for resection of petroclival chondrosarcomas.

Endoscopic Endonasal Transpterygoid Approach to Sphenoid Sinus Lateral Recess Defects.

Background Lesions affecting sphenoid sinus lateral recess (SSLR) are difficult to visualize and manipulate through the transnasal routes, especially when the sinus is highly pneumatized. External approaches to this area involve extensive surgery and are associated with significant morbidity. The aims of this study are to present our experience with the endoscopic transpterygoid approach as a method for approaching lesions of the SSLR and to evaluate the outcomes of this procedure. Methods Clinical charts of patients who had lesions in the SSLR and who were treated at our institution from September 1998 to June 2018 were retrospectively reviewed. All these patients were managed by the endoscopic endonasal transpterygoid approach. Results Thirty-nine patients were identified. No cerebrospinal fluid leak recurrences were observed during follow-up (range: 1-19.7 years; median: 2.3 years). Hypoesthesia (temporary, 1; persistent, 4) in the region innervated by the maxillary branch of the trigeminal nerve was detected in five (12.8%) patients, while symptoms due to the Vidian nerve damage (dry eye, 3; dry nasal mucosa, 1) were present in four (10%) patients. Conclusions Although the endoscopic endonasal transpterygoid approach is an excellent corridor for dealing with lesions of the SSLR, limited rate of neurologic and lacrimal complications was observed. Potential morbidity of the intervention should be discussed during preoperative counselling.

Visualisation of the vomerovaginal canal during endonasal transpterygoid approaches and CT imaging diagnosis.

The vomerovaginal canal (VVC) and palatovaginal canal (PVC) are two canals that open forward to the posterior wall of the pterygopalatine fossa (PPF). Although the anatomy and computed tomography (CT) appearances of the PVC have been well studied, the VVC has been rarely reported, especially in endoscopic examinations. Some studies have even failed to distinguish the PVC from the VVC on CT images. The purpose of this study was to demonstrate the anatomy of the VVC on endoscopy and reveal its differences from the PVC, and to analyse the relative positions of the VVC, PVC, and pterygoid canal on CT images. Ten dry skull bases were studied to observe the structures involved in the formation of the VVC. Dissection of four cadaveric heads was performed to demonstrate the anatomy of the VVC on endoscopy. Coronal CT image analysis in 70 patients was conducted to evaluate the distances and relative positions between the VVC, PVC, and pterygoid canal. The PVC and VVC were also compared on axial CT images. The osteological study showed the top wall of the VVC was the antero-inferior wall of the sphenoid sinus. The VVC may be a helpful landmark in endoscopic endonasal transpterygoid approaches. Steps and discrimination in the dissections of the VVC and PVC were described. The interval between the PVC and VVC could be observed on both coronal and axial CT images. The coronal CT images of patients showed differences in the positions and distances among the three canals at both the anterior and posterior apertures of the PVC. The VVC can be easily mistaken for the PVC if its existence is not suspected. The anatomical morphologies and trajectories of the VVC and PVC differed on both nasal endoscopy and CT. The existence of the VVC should be considered during surgery and CT diagnosis within this area.

Lateral Transorbital Versus Endonasal Transpterygoid Approach to the Lateral Recess of the Sphenoid Sinus—A Comparative Anatomic Study

The treatment of cerebrospinal fluid leaks of the lateral recess of the sphenoid sinus (LRSS) faces difficulties due to the deep location of the osseous defect. When treated with craniotomies, brain retraction is a concern. The endoscopic endonasal transpterygoid approach (EETA) is a direct and less invasive procedure; however, it may require transection of the vidian nerve (VN). To investigate the feasibility of a lateral transorbital approach (LTOA) as an alternative pathway to the LRSS that avoids VN sacrifice. Six embalmed heads with well-pneumatized LRSS were preselected by inspecting their computed tomography scans. One LTOA and one EETA were performed on 1 side of each specimen. The approaches were compared regarding working distance and neurovascular structures being sacrificed. The working area of the LTOA was also measured. The average working distances were 59.9 (±2.94) mm for the LTOA and 76.4 (±3.99) mm for the EETA (P <.001). The LTOA generated a working area with a diameter of 9 to 14 mm. The EETA demanded the sacrifice of VN and the sphenopalatine artery in all specimens to expose the LRSS. No neurovascular structures were found in the trajectory of the LTOA. The LTOA to the LRSS is feasible, with minimal risk of injuring neurovascular structures. It offers a shorter pathway when compared to the EETA. Although the LTOA provides no options for vascularized flap reconstruction, it allows immediate access to muscle grafts. The LTOA may serve as an alternative to treating cerebrospinal fluid leaks of the LRSS.