Graduated endoscopic multiangle approach for access to the infratemporal fossa: a cadaveric study with clinical correlates

Anatomic Study of Endoscopic Minimally Invasive Lateral Approach to the Infratemporal Fossa

OBJECTIVE

To investigate the feasibility and related anatomical structures of the infratemporal fossa (ITF) through minimally invasive endoscopic lateral approach, so as to provide anatomical data and basis for clinical surgery.

METHODS

Six adult cadaveric heads were used to simulate the surgical dissection of the ITF through a minimally invasive endoscopic lateral approach, and the important vessels, nerves, and other structures in the surgical pathway and the surrounding adjacent relationships were observed, and relevant pictures were collected.

RESULTS

The maxillary arteries of 6 cadaver specimens (12 sides) were located on the surface of the lateral pterygoid muscle in 9 cases, and between the upper and lower heads of the lateral pterygoid muscle in 3 cases, constant branches were the deep temporal artery, pterygoid artery, masseter artery, and buccal artery. The superior posterior alveolar nerve branches off V2 in the ITF and descends along with its accompanying artery by the posterior wall of the maxilla. The buccal nerve branches out from the mandibular nerve and passes between the superior and inferior pterygoid muscles, runs anteriorly between the temporalis and lateral pterygoid muscle, and innervates the buccal muscles.

CONCLUSION

The endoscopic minimally invasive lateral approach can expose the important structures, such as vessels and nerves related to the ITF well, and can be used as a minimally invasive surgical approach to treat the lesions of the infra- temporal fossa; it can also assist the endoscopic anterior approach to treat a series of lesions extending from the deep part of the pterygopalatine fossa to the posterior lateral side of the ITF.

Advantages and caveats of endoscopic to the infratemporal fossa as isolated and combined techniques

Objective

Identify the benefits and caveats of combining minimal access approaches to the infratemporal fossa (ITF), such as the endoscopic transnasal, endoscopic transorbital, endoscopic transoral, and endoscopic sublabial transmaxillary approaches to address extensive lesions not amenable to a single approach. The study provides anatomical metrics including area of exposure and degree of surgical freedom.

Methods

Five human cadaveric specimens (10 sides) were dissected to expose and methodically analyze the anatomical intricacies of the ITF using the following minimal access approaches: endoscopic transnasal transpterygoid (EETA), endoscopic sublabial transmaxillary, endoscopic transorbital via infraorbital foramen, and endoscopic transoral techniques. Area of exposure at the pterygopalatine fossa and surgical freedom at the ITF were obtained for each approach.

Results

The endoscopic sublabial transmaxillary sinus and the combined approach afford a significantly greater exposure than an isolated EETA. The difference in exposure (mean) between the endoscopic sublabial transmaxillary and EETA was 1.62 ± 0.85 cm2 (p < 0.001), and the difference between the combined approach and EETA was 4.25 ± 0.85 cm2 (p < 0.001).

Conclusions

Combining minimal access endoscopic approaches to the ITF can provide significantly greater exposure than an isolated EETA; thus, providing enhanced access to address lesions with extensive involvement of the ITF, especially those with superolateral and inferolateral extensions. In addition, some approaches may have an adjunctive role to the resection, such as the endoscopic transoral approach offering the potential for early control of the internal maxillary artery and its branches, some of which may be supplying the tumor in the ITF; or the endoscopic transorbital approach yielding a direct line of sight to the superior ITF and middle cranial fossa.

Level of Evidence

NA.

Anterior endoscopic sublabial transmaxillary access to middle cranial base lesions

BACKGROUND

Anterior endoscopic access to middle cranial base lesions becomes feasible in the presence of infratemporal fossa (ITF) involvement. Various approaches, including endoscopic endonasal, transoral sublabial, and transorbital methods, have been described for accessing the ITF through a transmaxillary corridor. Among these approaches, endonasal access is the most commonly preferred, while the transorbital approach is a novel technique gaining popularity. The transoral sublabial approach is considered suitable for selected lesions.

METHODS

Patients who underwent the anterior endoscopic transoral/sublabial transmaxillary approach to middle cranial base lesions at a single institute from 2016 to 2023 were included in this retrospective study. Malignant lesions were excluded from the study. The sublabial approach was exclusively performed in all cases, with the exception of one patient who required a combined approach.

RESULTS

The anterior endoscopic transoral sublabial transmaxillary approach to the infratemporal fossa, upper parapharyngeal space, and middle cranial fossa was performed on 14 patients. The underlying conditions for these patients were as follows: trigeminal schwannomas (n = 8), meningiomas (n = 2), juvenile nasopharyngeal angiofibroma, osteochondroma, arachnoid cyst and encephalocele (n = 1 each). Gross total resection was achieved in 11 cases. The most common complication was numbness in the territory of the maxillary and mandibular nerves (n = 4). Two patients needed endoscopic maxillary antrostomy for persistent suppuration. No wound problems or CSF rhinorrhea occurred. The average follow-up time was 26.6 months.

CONCLUSION

The endoscopic sublabial transmaxillary approach provides direct access to the infratemporal fossa and middle cranial base, enhancing the surgical range of maneuverability while sparing the sinonasal cavity. This procedure is safe, less invasive, and could be used as an efficient corridor for the resection of selected infratemporal fossa lesions with or without extension to the middle cranial base and parapharyngeal space.

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

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 Multiport Approach for Exenteration of the Infratemporal Fossa

OBJECTIVE

To demonstrate anatomic relationships pertinent to the endoscopic multiport approach to the infratemporal fossa (ITF). Discuss advantages and limitations of each individual approach.

STUDY DESIGN

Cadaveric study.

METHODS

Endoscopic and endoscopic-assisted endonasal transpterygoid, sublabial transmaxillary, endoscopic transorbital, and endoscopic transoral approaches to accessing the ITF were completed in five silicone-injected fresh cadaveric specimens (10 sides) with the assistance of 0, 30, and 45⁰ rods-lens endoscopes. Image guidance was used to confirm and document the anatomical relationships encountered in each approach.

RESULTS

The endonasal endoscopic transpterygoid approach provides better visualization and more direct exposure to median structures. Endoscopic-assisted sublabial transmaxillary approach enhances the field of exposure, angle of attack, and ease of instrumentation to the lateral part of the ITF. Endoscopic-assisted transorbital approach via the inferior orbital fissure provided cephalic and anterior access. Endoscopic-assisted transoral approach complements the access to lesions extending inferior to the hard palate or far lateral to the mandibular condyle.

CONCLUSIONS

A combination of minimal access infratemporal approaches can provide adequate exposure of the entire ITF while avoiding some of the morbidity associated with open approaches.

LEVEL OF EVIDENCE

NA Laryngoscope, 2023.

Endoscopic Endonasal Supraoptic and Infraoptic Approaches for Complex "Parasuprasellar" Lesions: Surgical Anatomy, Technique Nuances, and Case Series

Objective

The surgical management of lesions involving the lateral area of the suprasellar region, including the lateral aspect of the planum sphenoidale and the tight junction region of the optic canal (OC), anterior clinoid process (ACP), and internal carotid artery (ICA) and its dural rings, is extremely challenging. Here, these regions, namely, the “parasuprasellar” area, are described from the endonasal perspective. Moreover, the authors introduce two novels endoscopic endonasal supraoptic (EESO) and endoscopic endonasal infraoptic (EEIO) approaches to access the parasuprasellar area.

Methods

Surgical simulation of the EESO and EEIO approaches to the parasuprasellar area was conducted in 5 silicon-injected specimens. The same techniques were applied in 12 patients with lesions involving the parasuprasellar area.

Results

The EESO approach provided excellent surgical access to the lateral region of the planum sphenoidale, which corresponds to the orbital gyrus of the frontal lobe. With stepwise bone (OC, optic strut and ACP) removal, dissociation of the ophthalmic artery (OA) and optic nerve (ON), the EEIO approach enables access to the lateral region of the supraclinoidal ICA. These approaches can be used independently or in combination, but are more often employed as a complement to the endoscopic endonasal midline and transcavernous approaches. In clinical application, the EESO and EEIO approaches were successfully performed in 12 patients harboring tumors as well as multiple aneurysms involving the parasuprasellar area. Gross total and subtotal tumor resection were achieved in 9 patients and 1 patient, respectively. For two patients with multiple aneurysms, the lesions were clipped selectively according to location and size. Visual acuity improved in 7 patients, remained stable in 4, and deteriorated in only 1. No postoperative intracranial infection or ICA injury occurred in this series.

Conclusions

The EESO and EEIO approaches offer original treatment options for well-selected lesions involving the parasuprasellar area. They can be combined with the endoscopic endonasal midline and transcavernous approaches to remove extensive pathologies involving the intrasellar, suprasellar, sphenoid, and cavernous sinuses and even the bifurcation of the ICA. This work for the first time pushes the boundary of the endoscopic endonasal approach lateral to the supraclinoidal ICA and ON.

Endoscopic Endonasal and Transmaxillary Approach for Resection of Juvenile Nasopharyngeal Angiofibroma With Preoperative Embolization in a Child

ABSTRACT

A 13-year-old Japanese boy with a 6-month history of bilateral nasal obstruction and a 3-week history of recurrent epistaxis from the right nose was admitted to our department. Nasal endoscopy revealed a reddish, smooth-walled tumor occupying the right nasal cavity. Computed tomography scan revealed a 3.5 × 4.5 × 7.0-cm heterogeneously enhancing mass involving the right nasal cavity and extending posteriorly to the nasopharynx, and laterally to the pterygopalatine fossa and the medial part of the infratemporal fossa. We diagnosed as juvenile nasopharyngeal angiofibroma with Radkowski classification stage IIC. The internal maxillary and ascending pharyngeal arteries were embolized with polyvinyl alcohol followed by Embosphere using a conventional Seldinger technique. En bloc resection was performed with an endoscopic ipsilateral endonasal and sublabial Caldwell-Luc transmaxillary approach under general anesthesia. As of 3 years postoperatively, no recurrence has been found. We report a child case of juvenile nasopharyngeal angiofibroma successfully treated with less invasive surgery with preoperative embolization.

Endoscopic transorbital approach to the infratemporal fossa and parapharyngeal space: a cadaveric study

OBJECTIVE

The infratemporal fossa (ITF) and parapharyngeal space are anatomical regions that can be challenging to access without the use of complex, cosmetically disfiguring approaches. With advances in endoscopic techniques, a new group of surgical approaches to access the intracranial space through the orbit has been recently referred to as transorbital neuroendoscopic surgery (TONES). The objective of this study was to establish a transorbital endoscopic approach utilizing the inferior orbital fissure (IOF) to gain access to the ITF and parapharyngeal space and provide a detailed endoscopic anatomical description of this approach.

METHODS

Four cadaveric heads (8 sides) were dissected using a TONES approach through the IOF to reach the ITF and parapharyngeal space, providing stepwise dissection with detailed anatomical findings and a description of each step.

RESULTS

An inferior eyelid approach was made with subperiosteal periorbital dissection to the IOF. The zygomatic and greater wing of the sphenoid were drilled, forming the boundaries of the IOF. The upper head of the lateral pterygoid muscle in the ITF and parapharyngeal space was removed, and 7 distinct planes were described, each with its own anatomical contents. The second part of the maxillary artery was mainly found in plane 1 between the temporalis laterally and the lateral pterygoid muscle in plane 2. The branches of the mandibular nerve (V3) and middle meningeal artery (MMA) were identified in plane 3. Plane 4 was formed by the fascia of the medial pterygoid muscle (MTM) and the tensor veli palatini muscle. The prestyloid segment, found in plane 5, was composed mainly of fat and lymph nodes. The parapharyngeal carotid artery in the poststyloid segment, found in plane 7, was identified after laterally dissecting the styloid diaphragm, found in plane 6. V3 and the origin of the levator and tensor veli palatini muscles serve as landmarks for identification of the parapharyngeal carotid artery.

CONCLUSIONS

The transorbital endoscopic approach provides excellent access to the ITF and parapharyngeal space compared to previously described complex and morbid transfacial or transcranial approaches. Using the IOF is an important and useful landmark that permits a wide exposure.

Combined endoscopic endonasal and sublabial transmaxillary approach for resection of giant infratemporal fossa schwannoma with intracranial extension: operative video and technical nuances

Tumors of the infratemporal fossa (ITF) are surgically formidable lesions due to their deep location and proximity to critical neurovascular structures. Selecting the optimal surgical corridor for a giant ITF lesion with extensive medial and lateral extension can be challenging due to the limited surgical freedom offered by each individual approach. In this operative video, we demonstrate a case of a 44-year-old female with a giant ITF schwannoma with intracranial extension and erosion of the central skull base. Although we considered several surgical approaches, including a standard binostril endoscopic endonasal approach and an endoscopic Denker’s approach, we eventually chose a combined endoscopic endonasal and sublabial (Caldwell-Luc) transmaxillary approach. This combined approach provides significantly greater surgical freedom than a pure endonasal route to the lateral ITF. The sublabial Caldwell-Luc corridor provides a more direct “head-on” trajectory to the target of the lateral ITF than the pure endonasal route. This combined approach provides a multiportal, multicorridor access, allowing for more surgical freedom and preservation of the piriform aperture and nasolacrimal duct. This case illustrates the versatility of the combined endoscopic endonasal and sublabial transmaxillary approach for giant ITF tumors with significant lateral extension. The technical nuances and surgical concepts are demonstrated in this operative video manuscript.

The video can be found here: https://youtu.be/gy-pkjLdDgE.

Endoscopic-Assisted Lateral Corridor to the Infratemporal Fossa: Proposal and Quantitative Comparison to the Endoscopic Transpterygoid Approach

Objective  This study was aimed to propose an expanded endoscopic-assisted lateral approach to the infratemporal fossa (ITF) and compare its area of exposure and surgical freedom with the endoscopic endonasal transptergyoid approach (EETA). Methods  Anatomical dissections were performed in five cadaver heads (10 sides). The ITF was first examined through the endoscopically assisted lateral corridor, herein referred to as the endoscopic-assisted transtemporal fossa approach (TTFA). After that, the EETA was performed and coupled with two sequential maxillary procedures (medial maxillectomy [MM], and endoscopic-assisted Denker's approach [DA]). Using the stereotactic neuronavigation, measurements of the area of exposure and surgical freedom at the foramen ovale were determined for the previously mentioned approaches. Results  Bimanual exploration of the ITF through the endoscopic-assisted lateral approach was achieved in all specimens. The DA (729 ± 49 mm ² ) provided a larger area of exposure than MM (568 ± 46 mm ² ; p <  0.0001). However, areas of exposure were similar between the DA and the TTFA (677 ± 35 mm ² ; p  = 0.09). The surgical freedom offered by the TTFA (109.3 ± 19 cm ² ) was much greater than the DA (24.7 ± 4.8 cm ² ; p <  0.0001), and the MM (15.2 ± 3.2 cm ² , p <  0.0001). Conclusion  The study demonstrates the feasibility of the proposed approach to provide direct access to the extreme extensions of the ITF. The lateral corridor offers an ideal working area in the posterior compartment of the ITF without crossing over important neurovascular structures. The new technique may be used alone in selected primary ITF lesions or in combination with endonasal approaches in pathologies spreading laterally from the nose or nasopharynx.

Minimally Invasive Lateral Endoscopic Multiport Approach to the Infratemporal Fossa: A Cadaveric Study

BACKGROUND

Expanded endoscopic endonasal approaches to the infratemporal fossa (ITF) are increasingly performed owing to improved visualization and less morbidity compared with classic open approaches. Only a few studies in the literature investigated lateral endoscopic access to the ITF. The aim of this study was to examine the ITF with the minimally invasive endoscopically assisted Gillies approach with a trial of its expansion through a double port technique.

METHODS

The ITF was examined in 10 sides of 5 cadaveric heads using a lateral endoscopic assisted approach. A double portal technique was developed to allow bimanual dissection. Specific long angled skull base instruments were used for dissection under stereotactic guidance.

RESULTS

The endoscopic assisted Gillies approach permitted minimally invasive access to the complete anteroposterior extension of the ITF with sufficient mobility of surgical instruments. A new anatomic classification for the ITF from a lateral endoscopic perspective was introduced. The addition of the second port allowed bimanual dissection.

CONCLUSIONS

This cadaveric study shows the feasibility of an endoscopically assisted lateral approach to the ITF. The addition of a posterior port expands the approach through increasing the working area and enabling a bimanual dissection technique. Performed alone or combined with an anterior endoscopic transnasal approach, this technique offers minimally invasive access to the ITF. The development of specifically designed instruments would further improve this promising approach.

Endoscopic graduated multiangle, multicorridor resection of juvenile nasopharyngeal angiofibroma: an individualized, tailored, multicorridor skull base approach

OBJECT

Juvenile nasopharyngeal angiofibromas (JNAs) are formidable tumors because of their hypervascularity and difficult location in the skull base. Traditional transfacial procedures do not always afford optimal visualization and illumination, resulting in significant morbidity and poor cosmesis. The advent of endoscopic procedures has allowed for resection of JNAs with greater surgical freedom and decreased incidence of facial deformity and scarring.

METHODS

This report describes a graduated multiangle, multicorridor, endoscopic approach to JNAs that is illustrated in 4 patients, each with a different tumor location and extent. Four different surgical corridors in varying combinations were used to resect JNAs, based on tumor size and location, including an ipsilateral endonasal approach (uninostril); a contralateral, transseptal approach (binostril); a sublabial, transmaxillary Caldwell-Luc approach; and an orbitozygomatic, extradural, transcavernous, infratemporal fossa approach (transcranial). One patient underwent resection via an ipsilateral endonasal uninostril approach (Corridor 1) only. One patient underwent a binostril approach that included an additional contralateral transseptal approach (Corridors 1 and 2). One patient underwent a binostril approach with an additional sublabial Caldwell-Luc approach for lateral extension in the infratemporal fossa (Corridors 1–3). One patient underwent a combined transcranial and endoscopic endonasal/sublabial Caldwell-Luc approach (Corridors 1–4) for an extensive JNA involving both the lateral infratemporal fossa and cavernous sinus.

RESULTS

A graduated multiangle, multicorridor approach was used in a stepwise fashion to allow for maximal surgical exposure and maneuverability for resection of JNAs. Gross-total resection was achieved in all 4 patients. One patient had a postoperative CSF leak that was successfully repaired endoscopically. One patient had a delayed local recurrence that was successfully resected endoscopically. There were no vascular complications.

CONCLUSIONS

An individualized, multiangle, multicorridor approach allows for safe and effective surgical customization of access for resection of JNAs depending on the size and exact location of the tumor. Combining the endoscopic endonasal approach with a transcranial approach via an orbitozygomatic, extradural, transcavernous approach may be considered in giant extensive JNAs that have intracranial extension and intimate involvement of the cavernous sinus.

Endoscopic endonasal approaches to infratemporal fossa tumors: a classification system and case series

OBJECTIVES/HYPOTHESIS

To propose a clinically applicable anatomic classification system describing three progressive endoscopic endonasal approaches (EEAs) to the infratemporal fossa (ITF) and their potential sequelae. Overall feasibility and outcomes of these approaches are presented through a consecutive case series.

STUDY DESIGN

Description of classification system for EEAs to the ITF and case series.

METHODS

A classification system of EEAs to ITF tumors was created based on the senior author's clinical experience and cadaveric dissection. A retrospective chart review of 21 child and adult patients with primary ITF tumors treated by these approaches from 2008 to 2012 at a tertiary-care academic medical center was conducted.

RESULTS

Three progressive EEAs to ITF tumors were defined: 1) a transpterygopalatine fossa approach, 2) a transmedial pterygoid plate approach, and 3) a translateral pterygoid plate approach. Twenty-one patients treated with these approaches were identified consecutively, with a mean age of 44.2 years (range, 11-79 years). Tumors primarily involving the pterygopalatine fossa and not the ITF were excluded. Pathology included three advanced juvenile nasopharyngeal angiofibromas, three adenoid cystic carcinomas, two recurrent inverted papillomas, two trigeminal schwannomas, and 11 other diverse skull base pathologies. No intraoperative or postoperative complications occurred, with a mean follow-up of 21.5 months (range, 1-55 months). Expected potential sequelae such as V2/palatal numbness, Eustachian tube dysfunction, and trismus occurred in 10/21 patients.

CONCLUSIONS

EEAs to ITF tumors are technically feasible with low risk of complications for well-selected patients. The proposed classification system is useful for anticipating potential sequelae for each approach.

Comparison of surgical freedom and area of exposure in three endoscopic transmaxillary approaches to the anterolateral cranial base

Objective Endoscopic ipsilateral endonasal transmaxillary, contralateral endonasal transseptal transmaxillary, and Caldwell-Luc approaches can access lesions within the retromaxillary space and pterygopalatine fossa. We compared the exposure and surgical freedom of these transmaxillary approaches to assist with surgical decision making. Design Four cadaveric heads were dissected bilaterally using the three approaches just described. Prior to dissection, stereotactic computed tomography (CT) scans were obtained on each head to obtain anatomical measurements. Surgical freedom and area of exposure were determined by stereotaxis. Main Outcome Measures Area of exposure was calculated as the extent of the orbital floor, maxillary sinus floor, nasal floor, and mandibular ramus exposed through each approach. Surgical freedom was the area through which the proximal end of the endoscope could be freely moved while moving the tip of the endoscope to the edges of the exposed area. Results The mean exposed area was similar: 9.9 ± 2.5 cm(2) (Caldwell-Luc), 10.4 ± 2.6 cm(2) (ipsilateral endonasal), and 10.1 ± 2.1 cm(2) (contralateral transseptal) (p > 0.05). The surgical freedom of the Caldwell-Luc approach (113 ± 7 cm(2)) was greater than for either endonasal approach, 76 cm(2 )± 15 (p = 0.001) (ipsilateral endonasal) and 83 cm(2) ± 15 (p = 0.003) contralateral transseptal. Conclusions Our work demonstrates that the Caldwell-Luc endonasal approach offers greater surgical freedom than either approach for anterolateral skull base targets, although these approaches offer similar exposure.

Surgery for juvenile nasopharyngeal angiofibroma with lateral extension to the infratemporal fossa

OBJECTIVE

The study aimed to assess the usefulness of skull base surgery for large juvenile nasopharyngeal angiofibroma (JNA) with lateral extension to the infratemporal fossa.

MATERIALS AND METHODS

Eleven cases were enrolled for this study, and the mean age was 17.7 years old (range: 8-32). Six out of 11 cases underwent surgery as an initial treatment, and the other five underwent secondary surgery after initial surgery or radiotherapy in other institutions. The range of extension of tumor, feeding arteries, surgical approach, and treatment outcome were estimated.

RESULTS

All tumors originated from the sphenopalatine foramen. Based on the imaging study, there was extension to the cavernous sinus observed in eight cases, as well as to the middle cranial fossa (8), orbit (4), and anterior cranial fossa (1). These tumors were diagnosed as Andrews' Stage IVa (3) and IVb (8). However, infiltration into the cavernous sinus was observed in one case only during surgery. Ten tumors were separated carefully from the cavernous sinus or dura and were accurately diagnosed as Stage IIIb. In all cases, the main arterial feeders of the JNAs were branches of the external carotid artery, which were embolized prior to surgery. However, 10 cases were also fed by branches of the internal carotid artery (branches of the ophthalmic artery), in which these arteries could not be embolized. Coronal skin incision (1) and a facial dismasking flap (9) were used, and in one case, wide lateral skin incision with temporary incision of the facial nerve was applied. The orbito-zygomatic approach and its modification was applied to all the cases. Fronto-lateral craniotomy was applied in four cases and lateral craniotomy in seven cases. Total resection was achieved in 10 cases and subtotal resection in one case. No mortality was noted in this series. Temporal trismus was observed in all cases which subsided gradually. Cheek numbness and facial palsy were observed in three and two cases, respectively.

CONCLUSION

Coupled with craniotomy, tumor removal was successfully carried out in 11 patients with JNAs, which showed large lateral extension. Our surgical strategy is a safe and effective approach for the removal of JNAs with infratemporal fossa extension.

Endoscopic nonembolized resection of an extensive sinonasal cavernous hemangioma: A case report and literature review

Sinonasal hemangiomas, although rare, must be considered in the evaluation of intranasal masses with profuse epistaxis. Although the availability of literature discussing cavernous hemangiomas in this location is limited, there have been no case reports of exclusively soft tissue sinonasal cavernous hemangiomas extending to the anterior skull base (ASB) that were resected purely endoscopically. Here, we describe the successful endoscopic resection of an extensive right sinonasal cavernous hemangioma extending to but not invading the ASB. Although highly vascular, in select cases, these tumors can be successfully resected endoscopically without embolization by experienced endoscopic sinus and skull base surgeons.

Endonasal, transmaxillary, transpterygoid approach to the foramen ovale: radio-anatomical study of surgical feasibility

Objective:

This study aimed to examine the feasibility of an endonasal, transmaxillary, transpterygoid approach to the foramen ovale by examining key anatomical, radiological and surgical landmarks.

Method:

Measurements were taken from 183 patients' computed tomography scans using BrainLAB iPlan 1.1 Cranial software. Endoscopic dissection was then carried out on a cadaver to assess surgical viability.

Results:

We found that the distances from the posterior maxillary wall to the foramen ovale and from the anterior nasal spine to the foramen ovale were statistically significantly larger in men than women. The distance from the base of the lateral pterygoid plate to the foramen ovale, and the angle between the foramen ovale, the anterior nasal spine and the sphenoid rostrum, were constant between the sexes. The importance of the lateral pterygoid plate in locating the foramen ovale was demonstrated.

Conclusion:

With the increasing popularity of image guidance and assisted navigation in endoscopic surgery, these findings increase anatomico-radiological understanding of the surgical approach investigated.

Geometric alopecia after preoperative angioembolization of juvenile nasopharyngeal angiofibroma

Resection of a juvenile nasopharyngeal angiofibroma (JNA) is challenging because of high intraoperative blood loss secondary to the tumor's well-developed vascularity. Endoscopic sinus and skull base surgeons commonly collaborate with neurointerventionalists to embolize these tumors before resection in an attempt to reduce the vascular supply and intraoperative bleeding. However, angioembolization can be associated with significant complications. Geometric alopecia from angioembolization of JNA has not been previously reported in the otolaryngologic literature. In this study, we discuss geometric alopecia from radiation exposure during preoperative angioembolization of a JNA.

Evaluating endoscopic and endoscopic-assisted access to the infratemporal fossa: a novel method for assessment and comparison of approaches

OBJECTIVES/HYPOTHESIS

Endoscopic infratemporal fossa (ITF) surgery is a growing clinical interest. This study presents a method of analyzing approach access and visualization, identifies relevant anatomy in an endoscopic approach to the ITF, and compares endoscopic medial maxillectomy (MMA) and endoscopic-assisted sublabial transmaxillary (SLT) approaches to the ITF as a model for this paradigm.

STUDY DESIGN

Human cadaver anatomic study.

METHODS

Five human cadaver heads (10 ITF dissections) were used. An SLT and MMA were performed on each side. For endoscopic dissections of the ITF, 0° and 30° endoscopes were used. Key landmarks were the posterior maxillary sinus wall, temporomandibular joint, pterygoid plates, foramen spinosum, and foramen ovale. Open dissection was used to confirm ITF landmarks. A novel measurement method using angles of approach and visualization was used to compare approaches.

RESULTS

Visualization and mobility in SLT and MMA were significantly different. The lateral extent and greatest average depth for dissection was 7.9 cm in MMA and 6.1 cm for SLT. The average angle of mobility in approach was 36.3° for MMA and 57.9° for SLT. Average visualization was 40.2° for MMA and 126.5° for SLT. Despite these differences, both surgical approaches allowed access and visualization to all targeted landmarks.

CONCLUSIONS

This evaluation paradigm provides useful data in evaluating an endoscopic or endoscopic-assisted approach to the ITF. Using this paradigm, the SLT and MMA were analyzed. Each provided adequate access to the ITF, but visualization and maneuverability were better in SLT.

Comparative analysis of surgical freedom and angle of attack of two minimal-access endoscopic transmaxillary approaches to the anterolateral skull base

OBJECTIVE

Surgical freedom and the angle of attack influence approach selection for open cranial base approaches, but these concepts have not been well studied in minimal-access endoscopic approaches. We therefore developed a methodology to study surgical freedom and angle of attack in two endoscopic transmaxillary transpterygoid approaches, the endonasal ipsilateral uninostril medial maxillotomy and the sublabial Caldwell-Luc anterior maxillotomy.

METHODS

Dissections were performed bilaterally in three formalin-fixed cadaver heads (six sides). For each approach, three progressively lateral and posterior anatomic targets were identified. Utilizing frameless stereotaxy, surgical freedom using the vector cross-product method was calculated for both approaches for each target. The mean and maximum possible angles of attack were calculated in the axial and sagittal planes.

RESULTS

Compared to the endoscopic endonasal-transmaxillary approach, the endoscopic Caldwell-Luc approach offered significantly greater surgical freedom to the genu of the internal carotid artery (P=0.02), foramen rotundum (P=0.03), and foramen ovale (P=0.03). Mean and maximum possible angles of attack were also significantly different between the two approaches for each target. The Caldwell-Luc approach offered a more bottom-up approach in the sagittal plane and a more head-on approach in the axial plane to each target (P<0.05).

CONCLUSIONS

We have successfully developed a model for comparing endoscopic skull base approaches. Both the endonasal medial maxillotomy approach and Caldwell-Luc approach provided endoscopic access to each target. However, the sublabial Caldwell-Luc approach offered greater surgical freedom and a more head-on approach than the endonasal medial maxillotomy. These differences in surgical freedom and angles of attack may be useful to consider when planning minimal-access approaches.

Celebrating the golden anniversary of anterior skull base surgery: reflections on the past 50 years and its historical evolution

With its inception nearly half a century ago through the pioneering work of Dandy, McLean, and Smith, anterior skull base (ASB) surgery is a relatively young discipline. It became a distinct entity in 1963 when Ketcham popularized the combined transcranial transfacial approach for en bloc resection of tumors of the paranasal sinuses extending into the anterior cranial fossa. However, because these procedures resulted in major morbidities and mortalities, alternative modes of treatment were sought. Since the 1970s, the introduction and promotion of the surgical endoscope by Messerklinger, Stammberger, and Kennedy, commenced the era of endoscopic sinus surgery. Thaler and colleagues described the utility of the endoscope for ASB surgery at the turn of the century. This allowed direct visualization and safer, more accurate removal of tumors. In 2001, Casiano reported the first purely endoscopic endonasal ASB resection, a novel technique that has been adopted by major skull base centers. The success of ASB surgery can be attributed to both the development of the skull base team as well as improvements in surgical techniques, instrumentation, and visualization technology. In this article, we review the historical evolution of ASB surgery as we approach the 50th anniversary since its recognition as a distinct entity.