Modified infratemporal fossa approach via lateral transantral maxillotomy: a microsurgical model

Giant Pleomorphic Adenoma of Infratemporal Fossa: A Rare Case Report

Of all the head and neck tumors, salivary gland tumors account to 3%. Pleomorphic adenomas are one of the most common benign tumors arising from major salivary glands, although it could also develop from minor salivary glands situated at accessory sites like nasal cavity, pharynx, parapharyngeal space, lacrimal glands etc. Tumors of infratemporal fossa are quite unusual, mainly because of its hidden location in retromaxillary region. We report an unusual case of 65 years old male presenting with complaint of progressive left cheek swelling for 4 years. FNAC revealed pleomorphic adenoma of minor salivary gland tumor. Intraoperatively a giant lobulated tumor was seen occupying almost whole space of infratemporal fossa, which was removed in-toto via open approach. Patient was kept on regular follow up with no evidence of recurrence reported till date.

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 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.

Temporal Galeofascial Flap for Reconstruction After Transmaxillary Approaches to the Clival Region

BACKGROUND

A paramount concern after transmaxillary approaches has been skull base reconstruction. Regional pedicled flaps represent the best reconstructive option. We have described a technique to harvest a lateral-based multilayered vascularized flap for skull base reconstruction after resection of large tumors using the transmaxillary transpterygoid approach (TMTPA).

METHODS

We performed a cadaver study using the TMTPA to harvest the combined temporal galeofascial flap (CTGF). The first layer, with major sealing capabilities, is composed by a temporoparietal galeal-pericranial flap. The second layer is composed by temporal muscle fascia to provide mechanical support for flap dural engrafting.

RESULTS

The CTGF provides excellent coverage of both the clival dural lining and the ipsilateral pterygopalatine fossa structures (×1.6). The CTGF is pliable and easy to harvest. It offers great flexibility in flap content and design, providing a large quantity of vascularized tissue. The vascular pedicle derives from the superficial temporal vessels, which can ensure flap trophism.

CONCLUSIONS

CTGF represents an effective option as a regional multilayered pedicled flap for skull base reconstruction after resection of clival tumors using the TMTPA. The flap pedicle, owing to its anatomical location, will often be preserved even after repeated microsurgical or endoscopic procedures, providing a technical alternative for reconstruction even in patients who have undergone multiple surgeries with low residual availability of regional flaps.

Infratemporal fossa approach: the modified zygomatico-transmandibular approach

Background

The infratemporal fossa (ITF) is an anatomical lateral skull base space composed by the zygoma, temporal, and the greater wing of the sphenoid bone. Due to its difficult approach, surgical intervention at the ITF has remained a heavy burden to surgeons. The aim of this article is to review basic skull base approaches and ITF structures and to avoid severe complications based on the accurate surgical knowledge.

Methods

A search of the recent literature using MEDLINE (PubMed), Embase, Cochrane Library, and other online tools was executed using the following keyword combinations: infratemporal fossa, subtemporal fossa, transzygomatic approach, orbitozygomatic approach, transmaxillary approach, facial translocation approach, midface degloving, zygomatico-transmandibular approach, and lateral skull base. Aside from our Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) trial, there have been very few randomized controlled trials. The search data for this review are summarized based on the authors’ diverse clinical experiences.

Results

We divided our results based on representative skull base approaches and the anatomy of the ITF. Basic approaches to the ITF include endoscopic endonasal, transzygomatic, orbitozygomatic, zygomatico-transmandibular, transmaxillary, facial translocation, and the midfacial degloving approach. The borders and inner structures of the ITF (with basic lateral skull base dissection schemes) are summarized, and the modified zygomatico-transmandibular approach (ZTMA) is described in detail.

Conclusions

An anatomical basic knowledge would be required for the appropriate management of the ITF pathology for diverse specialized doctors, including maxillofacial, plastic, and vascular surgeons. The ITF approach, in conjunction with the application of microsurgical techniques and improved perioperative care, has permitted significant advances and successful curative outcomes for patients having malignancy in ITF.

Eustachian Tube as a Landmark to the Internal Carotid Artery in Endoscopic Skull Base Surgery

OBJECTIVE

The purpose of this study was to probe the relationship between the eustachian tube and the internal carotid artery in skull base surgery by an intranasal endoscopic approach.

STUDY DESIGN

Cadaver study and illustrative cases.

SETTING

Minimally invasive surgery laboratory and operating room.

SUBJECTS AND METHODS

A series of 5 cadaveric heads were dissected to elaborate on the relevant surgical anatomy about the eustachian tube and the internal carotid artery. Three cases were presented to illustrate the application of our laboratory findings.

RESULTS

The bony-cartilaginous junction of the eustachian tube was just anterior to the first genu of the internal carotid artery by an intranasal endoscopic approach. The 3 patients in our study tolerated the procedure well and experienced no serious complications after surgery.

CONCLUSIONS

The anatomic data and clinical cases in this study confirmed that the eustachian tube is a consistent and reliable landmark to the internal carotid artery to avoid its injury in skull base surgery through the endoscopic endonasal route.

Middle infratemporal fossa less invasive approach for radical resection of parapharyngeal tumors: surgical microanatomy and clinical application

Surgery of the infratemporal fossa (ITF) and parapharyngeal area presents a formidable challenge to the surgeon due to its anatomical complexity and limited access. Conventional surgical approaches to these regions were often too invasive and necessitate sacrifice of normal function and anatomy. To describe a less invasive transcranial extradural approach to ITF parapharyngeal lesions and to determine its advantages, 17 patients with ITF parapharyngeal neoplasms who underwent tumor resection via this approach were enrolled in the study. All lesions located in the ITF precarotid parapharyngeal space were resected through a small operative corridor between the trigeminal nerve third branch (V3) and the temporomandibular joint (TMJ). Surgical outcomes and postoperative complications were evaluated. Pathological diagnosis included schwannoma in eight cases, paraganglioma in two cases, gangliocytoma in two cases, carcinosarcoma in one case, giant cell tumor in one case, pleomorphic adenoma in one case, chondroblastoma in one case, and juvenile angiofibroma in one case. Gross total resection was achieved in 12 cases, near-total and subtotal resection were in 3 and 2 cases, respectively. The most common postoperative complication was dysphagia. Surgical exposure can be customized from minimal (drilling of retrotrigeminal area) to maximal (full skeletonization of V3, removal of all structures lying lateral to the petrous segment of internal carotid artery) according to tumor size and location. Since the space between the V3 and TMJ is the main corridor of this approach, the key maneuver is the anterior translocation of V3 to obtain an acceptable surgical field.

Proposed classification of auriculotemporal nerve, based on the root system

The topography of the auriculotemporal nerve (ATN) root system is the main criterion of this nerve classification. Previous publications indicate that ATN may have between one and five roots. Most common is a one- or two-root variant of the nerve structure. The problem of many publications is the inconsistency of nomenclature which concerns the terms “roots”, “connecting branches”, or “branches” that are used to identify the same structures. This study was performed on 80 specimens (40 adults and 40 fetuses) to propose a classification based on: (i) the number of roots, (ii) way of root division, and (iii) configuration of interradicular fibers that form the ATN trunk. This new classification is a remedy for inconsistency of nomenclature of ATN in the infratemporal fossa. This classification system has proven beneficial when organizing all ATN variants described in previous studies and could become a helpful tool for surgeons and dentists. Examination of ATN from the infratemporal fossa of fetuses (the youngest was at 18 weeks gestational age) showed that, at that stage, the nerve is fully developed.

Mini-invasive surgery of infratemporal fossa schwannomas

Background:

Infratemporal fossa schwannomas are benign, encapsulated tumours of the trigeminal nerve limited to the infratemporal fossa. Because of the complications and significant morbidity associated with traditional surgical approaches to the infratemporal fossa, which include facial nerve dysfunction, hearing loss, dental malocclusion and cosmetic problems, less invasive alternatives have been sought.

Methods:

This paper reports two cases of infratemporal fossa schwannomas treated in 2012 using mini-invasive approaches. The literature regarding different infratemporal fossa approaches was reviewed.

Results:

The first schwannoma was 30 mm in size and was removed completely by a preauricular subtemporal approach. The second one was 25 mm in size and was removed completely using a purely transnasal endoscopic approach. In both cases, there were no intra-operative or post-operative complications.

Conclusion:

These two approaches allow non-invasive and wide exposure of the infratemporal fossa as compared to classical approaches. Surgical approach should be selected according to the tumour's anatomical location with respect to the maxillary sinus posterior wall. The preauricular subtemporal approach is recommended for tumours localised posterolaterally with respect to the maxillary sinus posterior wall. Medial and anterior tumours near the maxillary sinus posterior wall can be best removed using a transnasal endoscopic approach.

Surgical safety distances in the infratemporal fossa: three-dimensional measurement study

The wedge-shaped infratemporal fossa is a constricted space and has long been a surgical challenge, mainly due to difficulties in access. Three-dimensional (3D) reconstruction of the skull, internal carotid artery (ICA), and internal jugular vein (IJV) was carried out using enhanced computed tomography (CT) data, to measure the safety distances in relation to infratemporal fossa surgery. Fifty enhanced CT datasets were selected to reconstruct 3D images by segmentation technique. The anatomical routes of the ICA, IJV, and the styloid process (SP) were observed. The following were measured: SP length, height of the pterygoid plates (PP height), distances from the pterygoid process (antero-inferior and anterosuperior border) to the leading edge of the ICA (PP-ICA (inferior), PP-ICA (superior)), and distance between the most prominent point of the zygomatic arch and the medial pterygoid plate (Zyg-MPP). The mean measurements of SP length, PP height, and the distances PP-ICA (inferior), PP-ICA (superior), and Zyg-MPP were 30.64 mm, 26.61 mm, 31.16 mm, 34.37 mm, and 51.37 mm, respectively. No significant differences were observed by age group, except the distance of PP-ICA (inferior) on the left side. In centres without intraoperative navigation facilities, proper knowledge of the anatomy, particularly of bony landmarks and the safe distances to nearby neurovascular structures, can provide useful information to ensure safe operations.

Maxillary-fronto-temporal approach for removal of recurrent malignant infratemporal fossa tumors: Anatomical and clinical study

PURPOSE

For recurrent malignant tumors occurring in the infratemporal fossa, it is difficult to select a proper surgical approach. We explore the efficiency of a new approach for removal of recurrent malignant tumors involving the infratemporal fossa based on the measurement on three-dimension CT, observation of six cadaveric specimens, and our surgical experience.

MATERIALS AND METHODS

The distances between the surgical landmarks in the infratemporal fossa were measured using CT data to determine the safe distance. And anatomy observation was examined on 6 formalin-fixed cadaveric specimens. Data from seven patients with recurrent malignant infratemporal fossa tumors were retrospectively analyzed.

RESULTS

The mean distance of the medial pterygoid plate from the zygoma was 52.12 mm. The maxillary artery can be found between the deep surface of the condyle and the sphenomandibular ligament, with mean distance of 8.25 ± 3.22 mm to the inferior border of the capsule of the temporomandibular joint. All tumors got gross resection using the maxillary-fronto-temporal approach with minor complication.

CONCLUSIONS

The advantages of the new approach include adequate protection of facial nerve with extended operation field; the exposed temporal muscle could be used to fill the dead space. This technique is especially useful to remove recurrent malignant infratemporal tumors safely.

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

OBJECTIVE

The infratemporal fossa (ITF) has historically been one of the most difficult regions of the skull base to access surgically. Available open approaches are complex, are associated with high morbidity, and do not always afford optimal visualization. Endoscopic access to the ITF improves visualization for management of many sinonasal and lateral skull base lesions involving this region. The purpose of this study is to evaluate a graduated multiangle approach for endoscopic access to this area using a cadaveric model.

STUDY DESIGN AND SETTING

Cadaveric study at an academic medical center.

METHODS

Endoscopic dissection was performed on a total of 10 sides of 5 fresh cadaveric heads. Four different approaches to the ITF were studied: ipsilateral endonasal, endoscopically assisted Caldwell-Luc, contralateral endonasal via septotomy, and endoscopically assisted Gillies transtemporal. High-quality endoscopic pictures and high-definition videos of each technique were obtained in order to document the differences in access achieved with each approach.

RESULTS

The combination of the 4 different endoscopic techniques allowed complete access to all areas of the ITF. The endoscopically assisted Caldwell-Luc improved anteroposterior access, the contralateral septotomy approach resulted in excellent far lateral access, and the endoscopically assisted Gillies approach allowed posterosuperior visualization and instrumentation.

CONCLUSION

Endoscopic access to the ITF can be accomplished by each of the 4 methods described. A multiangle, graduated approach can provide surgeons the ability to customize surgical access depending on the location of a specific lesion within the ITF.

Microanatomy and surgical approaches to the infratemporal fossa: an anaglyphic three-dimensional stereoscopic printing study

OBJECTIVE

The infratemporal fossa (ITF) is a continuation of the temporal fossa between the internal surface of the zygoma and the external surface of the temporal bone and greater wing of the sphenoid bone that is sitting deep to the ramus of the mandible. The principal structure to understanding its relationships is the lateral pterygoid muscle. Other important structures are the medial pterygoid muscle, the maxillary artery, the pterygoid venous plexus, the otic ganglion, the chorda tympani nerve and the mandibular nerve. In this study, we describe the microsurgical anatomy of the ITF, as viewed by step-by-step anatomical dissection and also through the perspective of three lateral approaches and one anterior surgical approach.

METHODS

Eight cadaver specimens were dissected. In one side of all specimens, an anatomical dissection was done in which a wide preauricular incision from the neck on the anterior border of the sternoclidomastoid muscle at the level of the cricoid cartilage to the superior temporal line was made. The flap was displaced anteriorly and the structures of the neck were dissected followed by a zygomatic osteotomy and dissection of the ITF structures. On the other side were the surgical approaches to the ITF. The combined infratemporal and posterior fossa approach was done in two specimens, the subtemporal preauricular infratemporal fossa approach in two, the zygomatic approach in two, and the lateral transantral maxillotomy in two. The anatomical dissections were documented on the three-dimensional (3D) anaglyphic method to produce stereoscopic prints.

RESULTS

The lateral pterygoid muscle is one of the principal structures to enable understanding of the relationships into the ITF. The tendon of the temporal muscle inserts in the coronoid process at the ITF. The maxillary artery is the terminal branch of the external carotid artery that originates at the neck of the mandible and runs into the parotid gland. In our dissections the maxillary artery was lateral to the buccal, lingual, and inferior alveolar nerves. We found the second part of the maxillary artery superficial to the lateral pterygoid muscle in all specimens The anterior and posterior branches of the deep temporal artery supply the temporal muscle. In two cases we found a middle deep temporal artery. The different approaches that we used provided different views of the same anatomical landmarks and this provides not only safer surgery but also the best choice to approach the ITF according with the pathology extension.

CONCLUSIONS

The ITF is a complex region on the skull base that is affected by benign and malignant tumors. The study through different routes is helpful to disclose the relationship among the anatomical structures. Although the authors have shown four approaches, there are a variety of approaches and even a combination of these can be used. This type of anatomical knowledge is essential to choosing the best approach to treat lesions in this area.

Topography of the third portion of the maxillary artery via the transantral approach in Asians

The maxillary artery (MA) passes over the lateral pterygoid muscle in the infratemporal fossa and enters the pterygopalatine fossa through the pterygomaxillary fissure. Refractory epistaxis is managed by ligation of the sphenopalatine artery via a transmaxillary-transantral approach; there is considerable risk of complications associated with such invasive surgical approaches. The aim of this study was to describe the gross anatomy and variations therein of the MA and its branches at the pterygopalatine fossa. One hundred hemifaces of embalmed Korean adult cadavers were dissected to establish the precise course of the MA and its branching patterns. The average thickness of the posterior wall of the maxillary sinus was 0.8 mm, but varied over a wide range from 0.2 to 3.6 mm. We classified the third part of the MA into 3 morphological categories: looped (61%), bifurcated (19%), and straight (18%). Two cases could not be classified into any of these 3 categories. The pattern of the bifurcation between the sphenopalatine and descending palatine arteries was classified into 4 types: Y (19%), intermediate (36%), M (17%), and T (28%). The posterior wall of the maxillary sinus was divided into 9 sections. The branching areas of the sphenopalatine and descending palatine arteries were most frequently (62% of cases) located at the top of the medial partition and at the middle of the medial partition (30% of cases).

Fully endoscopic transnasal approach to the jugular foramen: anatomic study and clinical considerations

BACKGROUND AND IMPORTANCE

To describe a transnasal endoscopic route to the jugular foramen and the endoscopic anatomy of the infratemporal fossa.

CLINICAL PRESENTATION

Endoscopic transnasal dissection of the infratemporal fossa was performed in 3 injected fresh heads (1 head only in arteries and 2 heads in arteries and veins). Two other double-injected specimens were dissected externally (2 of them side laterally and 1 anteriorly) to compare the different views and better understand the 3-dimensionality of the region.Detailed endoscopic anatomy of the infratemporal fossa was clearly observed. The realization of a septal and posterior maxillary window allows surgeons to gain space to the jugular foramen. The ability to manage the vessels, especially the veins, and identify the muscles is mandatory. The fundamental role of the vidian canal in targeting the anterior genu of the internal carotid artery is confirmed. The role of the maxillary and mandibular branches of the trigeminal nerve and the eustachian tube in this kind of approach is critical.

CONCLUSION

A fully transnasal endoscopic route to the jugular foramen is feasible. The most important landmark for this kind of approach is the eustachian tube.

Temporal craniotomy for surgical access to the infratemporal fossa

We propose a surgical approach for select patients that minimizes morbidity while allowing gross total resection of lesions in the anterior portion of the infratemporal fossa. The approach we describe is an extradural approach through a subtemporal craniectomy or craniotomy with the possible addition of a zygomatic osteotomy. Lesions that have a well-defined capsule and a texture that permits manipulation are ideal for this less invasive approach. We retrospectively reviewed six cases from the primary author (C.B.H.) using a temporal craniectomy or craniotomy alone to resect lesions in the infratemporal fossa. All six cases had good clinical outcomes with no unexpected neurological deficits while achieving gross total resections. The only complication included one cerebrospinal fluid leak that was sealed endoscopically. For select lesions, a less morbid surgical approach via an extradural window through a subtemporal craniectomy or small craniotomy may be preferable to transfacial approaches. Adjuvant use of endoscopic techniques may facilitate surgical exposure and resection of large lesions.

Quantification of clival and paraclival exposure in the Le Fort I transmaxillary transpterygoid approach: a microanatomical study

OBJECT

The authors describe a modified Le Fort I maxillotomy with medial and posterior antrectomy and removal of the pterygoid plates, aimed at improving the lateral surgical exposure during open transmaxillary surgery for pathological conditions involving the clivus. A cadaveric microanatomical study was conducted to compare the planimetric exposures allowed by the transmaxillary transpterygoid (TMTP) approach and the standard Le Fort I maxillotomy (STM).

METHODS

Six cadaveric specimens that had been fixed with glutaraldehyde and injected with latex were dissected to obtain morphometric measurements after both TMTP and STM approaches. The anatomical areas exposed by the surgical approaches were calculated using ImageJ 1.37a software.

RESULTS

As expected, the TMTP approach allowed for a greater surgical exposure, with an incremental area exposed ranging from 4.9 to 7.6 cm(2) (mean ± standard deviation 6.4 ± 1.2 cm(2), 95% CI 5.4-7.4 cm(2)). The amount of additional anatomical area visualized, as recorded as a percentage increase after the TMTP approach when compared with the STM approach, ranged from 83 to 109% (mean 99%).

CONCLUSIONS

The lateral surgical exposure allowed by the STM approach is limited by the pterygoid plates. The TMTP approach significantly improves the exposure of the anatomical regions lateral to the clivus, allowing access to the pterygopalatine and medial infratemporal fossae. In comparison with the STM, the TMTP approach allows for a surgical exposure that is nearly double. The authors conclude that the TMTP approach provides a significant improvement in the surgical exposure of the lateral paraclival areas, when compared with the STM approach.

Neuro-ophthalmologic manifestations of benign anterior skull base lesions

Visual disturbance is a common presenting symptom of anterior skull base lesions. These lesions cause deterioration in visual acuity, restriction of the visual field, or reduction of ocular mobility. Common pathological entities that affect the skull base and involve vision include meningioma, pituitary adenoma, tumors of the bone, malignancy, and infection. Benign lesions are typically treated surgically with acceptable long-term results. In this article, we review the presentation, evaluation, and surgical treatment of patients with benign skull base lesions presenting with visual disturbance.

Vidian nerve schwannoma with middle cranial fossa extension resected via a maxillary swing approach

BACKGROUND

Vidian nerve schwannoma is an extremely rare type of facial nerve schwannoma. To the best of our knowledge, only 1 case has been reported.

METHODS

We report an additional case of vidian nerve schwannoma with middle cranial fossa extension in a 49-year-old Japanese woman. The surgical approaches for infratemporal fossa schwannomas are reviewed, and the maxillary swing approach we used is described.

RESULTS

We adopted a maxillary swing approach combined with endonasal endoscopic techniques for the resection of the lesion. Gross total resection was achieved without sacrificing the trigeminal nerves or the facial motor nerves. The postoperative course was uneventful.

CONCLUSION

Vidian nerve schwannoma is located in the retro-maxillary space. It can grow silently until it involves the median skull base extensively. The maxillary swing approach was useful in this case.

[Transmaxillary approach to the skull base: surgical anatomy and guidelines]

BACKGROUND

A surgical and anatomic approach to the skull base using the transmaxillary route is presented. This route is well-known and used for a long time for sinus conditions.

METHOD

This study was performed on injected cadavers. This study describes step by step this approach in microsurgical conditions following a vital lead: the infraorbital nerve.

RESULTS

Anatomical landmarks are located in order to avoid complications. These complications are on one hand, hemorrhages by vascular lesions and on the other, definitive nerve palsy.

CONCLUSION

Several skull base approaches exist, transfacial routes produce cosmetic damages. This route preserves the functional anatomy of the nose because it preserves the integrity of the lateral wall of the nasal cavity.

Endoscopic sublabial transmaxillary approach to the rostral middle fossa

OBJECTIVE

The rostral middle fossa faces the temporal pole and is the endocranial anterosuperior aspect of the greater wing of the sphenoid. Standard approaches to this region, such as the subtemporal, pterional, or orbitozygomatic approaches, require significant brain retraction or manipulation of the temporalis muscle. We report an endoscopic sublabial transmaxillary approach to this cranial base region that avoids the aforementioned pitfalls.

METHODS

Ten adult cadaveric half heads were used to develop the endoscopic approach and to identify the salient surgical landmarks.

RESULTS

The approach was divided into three stages: entry into the maxillary sinus, entry into the infratemporal fossa, and entry into the middle fossa. A craniotomy of greater than 20 mm in diameter can be safely created in the rostral middle fossa. When coupled with image guidance, the approach provides the flexibility to tailor the size and location of the middle fossa craniotomy.

CONCLUSION

Although endonasal endoscopic approaches are increasing in popularity, the middle fossa has not been adequately accessed with these techniques. The endoscopic sublabial transmaxillary approach provides safe and direct access to the rostral middle fossa, eliminating the need for brain retraction, temporalis muscle manipulation, or an external incision. The approach also permits early devascularization of cranial- or dural-based lesions.

Transmaxillary exploration of the intracranial portion of the maxillary nerve in malignant perineural disease

Object

Achieving microscopically tumor-free margins during resection of skull base malignancies has consistently been identified as a positive prognostic factor for patient survival. When malignancies extend perineurally into the major nerves traversing the skull base and entering the cavernous sinus, achieving tumor-free margins can be challenging and typically necessitates performing a craniotomy to access the lateral wall of the cavernous sinus. This report describes a novel technique used to access and resect malignancy extending perineurally into the intracranial portion of V2 via the maxillary sinus.

Methods

Seven patients with maxillary sinus tumors and perineural extensions along V2, who underwent resection of the primary tumor and transmaxillary intracranial exposure and dissection of the maxillary nerve to achieve maximal tumor resection, were analyzed. Prospectively collected data, including symptoms, clinical signs, diagnostic imaging data, pathological diagnosis, incidence and nature of complications, adjuvant therapies, and oncological outcomes, were retrospectively analyzed.

Results

All patients in this cohort had trigeminal nerve symptomatology as well as abnormal enhancement in the pterygopalatine fissure as noted on magnetic resonance imaging. The transmaxillary exploration of the maxillary nerve technique was used in all seven patients, resulting in gross-total resection of the tumors in every patient. At the last follow-up (mean 30 months, range 13–58 months, in four of seven patients for > 2 years), six patients were alive without evidence of local disease. One patient with squamous cell carcinoma died of progressive infratemporal fossa and regional neck disease 26 months after resection. No intracranial or cavernous sinus disease was present.

Conclusions

This technique extended the limits of resection without the need for a craniotomy and improved local tumor control in this patient cohort.

Treatment of lesions involving both the infratemporal fossa and middle skull base

BACKGROUND

Communicating occupying lesions of the intratemporal fossa and mid-cranial fossa represent challenges for neurosurgeons and maxillofacial surgeons. Lesions of the skull base, with complex anatomy, are extremely varied in their histopathology. They often spread via normal anatomic pathways or bony destruction to involve adjacent structures, especially in the case of malignant neoplasms. However, with the development of operative skills and reconstruction techniques, total or near total resection of many such lesions can be accomplished with a low morbidity rate.

METHODS

The combined frontotemporal-preauricular infratemporal approach, frontotemporal-orbitozygomatic approach, combined frontotemporal and transmandibular approach, transmandibular approach, and transmaxillary approach were used to resect the lesions using microsurgical skills. The plastic reconstruction included reconstruction of the dura defects, osteosynthesis, and obliteration of the operative cavity.

RESULTS

Thirty-three patients with communicating lesions invading both the infratemporal fossa and the middle skull base underwent microsurgery. Among them, lesions were totally resected in 23, subtotally resected in 6, and partially resected in 4. In 29 patients, clinical status improved significantly. Complications were encountered in 7 cases, and morbidity was not remarkable.

CONCLUSION

The surgical approach should be selected depending on the size, location, histopathology, and invading extension of the lesion, which can provide excellent visualization and allow for an aggressive and safe resection of lesions involving this region. Familiarity with skull base anatomy, careful microsurgical manipulation, protection of vital structures, reliable plastic reconstruction, intraoperative nerve monitoring, as well as consideration of functional and esthetic outcomes, will all contribute to successful surgery and satisfactory results.

Endoscopic management of benign tumors extending into the infratemporal fossa: a two-surgeon transnasal approach

OBJECTIVES/HYPOTHESIS

Preliminary results of the endoscopic two-surgeon technique for the management of benign infratemporal fossa tumors are presented.

METHODS

Four patients with juvenile nasopharyngeal angiofibroma, a patient with an inverting papilloma, and a patient with a maxillary nerve schwannoma were reviewed. The average age was 22.7 years; the male-to-female ratio was 5:1. The endoscopic anatomy and surgical technique are presented.

RESULTS

The two-surgeon technique allowed complete resection of all six tumors extending into the infratemporal fossa. There has been no recurrence of tumor within the infratemporal fossa, after a mean follow-up of 31.3 months (SD = 11.2 mo).

CONCLUSION

The two-surgeon transnasal technique allows benign infratemporal fossa tumors to be resected endoscopically.