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

Course and Relation of the Facial Vessels-An Anatomical Study

Background and Objectives: Facial vascular anatomy plays a pivotal role in both physiological context and in surgical intervention. While data exist on the individual course of the facial artery and vein, to date, the spatial relationship of the vasculature has been ill studied. The aim of this study was to assess the course of facial arteries, veins and branches one relative to another. Materials and Methods: In a total of 90 halved viscerocrania, the facial vessels were injected with colored latex. Dissection was carried out, the relation of the facial vessels was studied, and the distance at the lower margin of the mandible was measured. Furthermore, branches including the labial and angular vessels were assessed. Results: At the base of the mandible, the facial artery was located anterior to the facial vein in all cases at a mean distance of 6.2 mm (range 0-15 mm), with three cases of both vessels adjacent. An angular vein was present in all cases, while an angular artery was only present in 34.4% of cases. Conclusions: The main trunk of the facial artery and vein yields a rather independent course, with the facial artery always located anterior to the vein, while their branches, especially the labial vessels, demonstrate a closer relationship.

Enbloc resection of primary oral cancer involving infratemporal fossa: A systematic "out to in and top to bottom" surgical approach and outcomes

AIM AND INTRODUCTION

The oral cavity Squamous Cell Carcinoma (OCSCC) involving infratemporal fossa (ITF) is considered as cT4b stage per AJCC 8th classification. The treatment of these group of patients is challenging due to the difficulty in achieving negative resection margin status. In this study we have highlighted our surgical technique with oncological outcome of enbloc resection of primary oral cancer involving ITF.

METHODOLOGY

- This was a single center retrospective study which included only patients with OCSCC extending into ITF. Our surgical technique of systematic "out to in and top to bottom" approach was detailed. The perioperative outcomes, histopathological details, survival outcomes were measured.

RESULTS

- Over the period of 1 year a total of 340 patients with OCSCC reported to our outpatient department, out of which 120 patients belonged to cT4 category and 32 patients were cT4b stage with involvement of ITF. Amongst 32 patients, 2 patients had distant metastasis and were excluded from the study. The 5 patients received neoadjuvant chemotherapy followed by surgery and rest all patients were taken up for upfront curative surgery. There were no significant intraoperative and postoperative complications. None of the margins were found to be involved or close in the final histopathology report. The median DFS and OS were 31 months and 27 months respectively at a median follow up of 29 months.

CONCLUSION

- Our systematic approach of enbloc resection of primary oral cancer involving ITF is safe and easily reproducible with high rate of negative resection margin status.

Predictors of postoperative performance status after surgical management of infratemporal fossa malignancies

Infratemporal fossa (ITF) tumors are difficult to access surgically due to anatomical constraints. Moreover, aggressive ITF carcinomas and sarcomas necessitate aggressive treatment strategies that, along with tumor-related symptoms, contribute to decreases in patient performance status. To assess factors that predict postoperative performance in patients undergoing surgery for ITF tumors. We reviewed medical records for all patients surgically treated for an ITF malignancy between January 1, 1999, and December 31, 2017, at our institution. We collected patient demographics, preoperative performance, tumor stage, tumor characteristics, treatment modalities, pathological data, and postoperative performance data. The 5-year survival rate was 62.2%. Higher preoperative Karnofsky Performance Status (KPS) score (n = 64; p < 0.001), short length of stay (p = 0.002), prior surgery at site (n = 61; p = 0.0164), and diagnosis of sarcoma (n = 62; p = 0.0398) were predictors of higher postoperative KPS scores. Percutaneous endoscopic gastrostomy (PEG) (n = 9; p = 0.0327), and tracheostomy tube placement (n = 20; p = 0.0436) were predictors of lower postoperative KPS scores, whereas age at presentation (p = 0.72), intracranial tumor spread (p = 0.8197), and perineural invasion (n = 40; p = 0.2195) were not. Male patients and patients with carcinomas showed the greatest decreases in KPS scores between pretreatment and posttreatment. Higher preoperative KPS score and short length of stay were the best predictors of higher postoperative KPS scores. This work provides treatment teams and patients with better information on outcomes for shared decision-making.

Assessment of Morphological Variations of the Coronoid Process, Condyle, and Sigmoid Notch as an Adjunct in Personal Identification Using Orthopantomograms Among the North Indian Population

AIM

The aim of this study is to assess morphological variations of the coronoid process, condyle, and sigmoid notch as an adjunct in personal identification using orthopantomograms among the North Indian population.

METHODOLOGY

The study sample (n=240) was distributed into four age groups: Group I: 30 males and 30 females aged 10-19 years, Group II: 30 males and 30 females aged 20-29 years, Group III: 30 males and 30 females aged 30-39 years, and Group IV: 30 males and 30 females aged 40-59 years. All were subjected to panoramic radiographs. The different morphological forms of the coronoid process, condyle, and sigmoid notch were evaluated.

RESULTS

The results showed that across all age groups, angular condyles were the most common kind of condyle in males, followed by round and convex types. The present study found that the coronoid process typically takes on a triangle shape across all ages and sexes. Additionally, the vast majority of cases were triangular on both sides, and this was true across both sexes. It was found in this study that the sigmoid notch most commonly took the form of a larger notch, followed by a rounder notch.

CONCLUSION

Using panoramic photos to portray the different morphologies of the coronoid process, condyle, and sigmoid notch can be a much simpler and faster method of identifying an individual, especially in the event of a mass disaster, so long as antemortem data are kept. The method of radiographic identification of individuals has recently gained prominence due to its efficacy. Radiographs like these can be invaluable in forensic dentistry, where they can help unearth previously hidden evidence if premortem records are retained. As a potential approach for individual identification among our population, panoramic radiographs were used to investigate the varying morphological forms of the coronoid process, condyle, and sigmoid notch.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

The Learning Curve in Skullbase Surgery Part 2–From the Microsurgical Lab Training to the Operative Room

In this second part, the authors review and suggest a methodology for studies in skull base surgery and training in microsurgical laboratory, based on their experiences and reflections. Not only are the foundations for the acquisition of microsurgical skills presented, but also what is needed to be an effective skullbase surgeon with good results. The present article reflects in particular the philosophy of professor Evandro de Oliveira and also serves to present to the neurosurgical community a new state-of-the-art laboratory for hands-on courses in Brazil, at the Faculdade Evangélica Mackenzie do Paraná.

Infra-Temporal and Pterygo-Palatine Fossae Tumors: A Frontier in Endoscopic Endonasal Surgery—Description of the Surgical Anatomy of the Approach and Report of Illustrative Cases

Infratemporal and pterygopalatine fossae (ITF and PPF) represent two complex paramedian skull base areas, which can be defined as jewelry boxes, containing a large number of neurovascular and osteomuscular structures of primary importance. They are in close communication with many craniofacial areas, such as nasal/paranasal sinuses, orbit, middle cranial fossa, and oral cavities. Therefore, they can be involved by tumoral, infective or inflammatory lesions spreading from these spaces. Moreover, they can be the primary site of the development of some primitive tumors. For the deep-seated location of ITF and PPF lesions and their close relationship with the surrounding functional neuro-vascular structures, their surgery represents a challenge. In the last decades, the introduction of the endoscope in skull base surgery has favored the development of an innovative anterior endonasal approach for ITF and PPF tumors: the transmaxillary-pterygoid, which gives a direct and straightforward route for these areas. It has demonstrated that it is effective and safe for the treatment of a large number of benign and malignant neoplasms, located in these fossae, avoiding extensive bone drilling, soft tissue demolition, possibly unaesthetic scars, and reducing the risk of neurological deficits. However, some limits, especially for vascular tumors or lesions with lateral extension, are still present. Based on the experience of our multidisciplinary team, we present our operative technique, surgical indications, and pre- and post-operative management protocol for patients with ITF and PPF tumors.

A Rare Case of Facial Artery Branching-A Review of the Literature and a Case Report with Clinical Implications

Background and Objectives: Vascular variations appear as morphologically distinct patterns of blood diverging from the most commonly observed vessel patterns. The facial artery is considered to be the main vessel for supplying blood to the anterior part of the face. An anatomical understanding of the facial artery, its course, its topography, and its branches is important in medical and dental practice (especially in neck and face surgery), and is also essential for radiologists to be able to interpret vascular imaging in the face following angiography of the region. A profound knowledge of the arteries in the region will aid in minimizing the risks to the patient. Materials and Methods: In our publication a narrative literature review and a case report are presented. Results: A rare case of a facial artery pattern has been described anatomically for the first time with respect to its course and branching. This variation was found on the left side of a 60-year-old male corpse during anatomical dissection. The anterior branch of the facial artery arched in the direction of the labial angle, and there divided into the inferior and superior labial arteries. At the same time, the posterior branch coursed vertically and superficially to the masseter muscle. It here gave off the premasseteric branch, and continued towards the nose, where it ran below the levator labii superioris and the levator labii superioris alaeque nasi muscles and terminated at the dorsum nasi. Conclusions: Our review of the literature and the case report add to knowledge on the facial artery with respect to its topographical anatomy and its branching and termination patterns, as well as the areas of supply. An exact knowledge of individual facial artery anatomy may play an important role in the planning of flaps or tumor excisions due to the differing vascularization and can also help to prevent artery injuries during aesthetic procedures such as filler and botulinum toxin injections.

Proximity of the middle meningeal artery and maxillary artery to the mandibular head and mandibular neck as revealed by three-dimensional time-of-flight magnetic resonance angiography

Purpose

The close topographic relationship between vascular and osseous structures in the condylar and subcondylar region and marked variability in the arterial course has been revealed by both imaging and cadaveric studies. This study aimed to verify the previously published information in a large sample and to determine a safe surgical region.

Methods

We analyzed the three-dimensional time-of-flight magnetic resonance angiography images of 300 individuals.

Results

The mean distance between the middle meningeal artery and the apex of the condyle or the most medial point of the condyle was 18.8 mm (range: 11.2–25.9 mm) or 14.5 mm (range: 8.8–22.9 mm) respectively. The course of the maxillary artery relative to the lateral pterygoid muscle was medial in 45.7% of cases and lateral in 54.3%. An asymmetric course was evident in 66 patients (22%). The mean distance between the maxillary artery and condylar process at the deepest point of the mandibular notch was 6.2 mm in sides exhibiting a medial course (range: 3.7–9.8 mm) and 6.6 mm in sides exhibiting a lateral course (range: 3.9–10.4 mm). The distances were significantly influenced by age, gender, and the course of the maxillary artery.

Conclusion

Our study emphasizes the marked inter- and intra-individual variability of the maxillary and middle meningeal arterial courses. We confirmed the proximity of the arteries to the condylar process. Extensive surgical experience and thorough preparation for each individual case are essential to prevent iatrogenic vascular injury.

Synchronous pleomorphic adenoma in the infratemporal fossa and contralateral submandibular gland and endoscopic removal

The objective of this article is to elucidate on our experience with the first case reported in the literature of a synchronous presentation of pleomorphic adenoma (PA) in infratemporal fossa as well as the contralateral submandibular gland. PA most commonly arises from the major salivary glands but has also been reported to arise from minor salivary glands in unusual sites such as the nasal septum, main stem bronchus, trachea, lacrimal gland, external auditory canal, etc. However, it seldom involves the infratemporal fossa and extremely few cases are reported in the literature and coexistent contralateral synchronous PA is nowhere reported in literature. The infratemporal fossa tumour posed a diagnostic dilemma and therapeutic challenge because of its concealed location which we dealt successfully with endoscopic sublabial trans maxillary approach.

The reproduction of human pathology specimens using three-dimensional (3D) printing technology for teaching purposes

The teaching of medical pathology has undergone significant change in the last 30-40 years, especially in the context of employing bottled specimens or 'pots' in classroom settings. The reduction in post-mortem based teaching in medical training programs has resulted in less focus being placed on the ability of students to describe the gross anatomical pathology of specimens. Financial considerations involved in employing staff to maintain bottled specimens, space constraints and concerns with health and safety of staff and student laboratories have meant that many institutions have decommissioned their pathology collections. This report details how full-colour surface scanning coupled with CT scanning and 3 D printing allows the digital archiving of gross pathological specimens and the production of reproductions or replicas of preserved human anatomical pathology specimens that obviates many of the above issues. With modern UV curable resin printing technology, it is possible to achieve photographic quality accurate replicas comparable to the original specimens in many aspects except haptic quality. Accurate 3 D reproductions of human pathology specimens offer many advantages over traditional bottled specimens including the capacity to generate multiple copies and their use in any educational setting giving access to a broader range of potential learners and users.

Infratemporal fossa surgical approaches to primary/recurrent malignancies of salivary origin: paradigm surgical shift, patient selection, and oncologic outcomes

PURPOSE OF REVIEW

To review, the surgical approaches available on diagnosing a patient with salivary gland malignancy in the infratemporal fossa (ITF). To comment on patient evaluation and method of treatment selection. To identify and report on patient outcome data and make recommendations on future needs.

RECENT FINDINGS

There is a need to define the anatomic boundaries contents of the ITF, masticator space, parapharyngeal space (PPS), pterygopalatine fossa, ventral skull base, and paramedian skull base, as evidence from publications. The pathological subtypes identified mainly include adenoid cystic and mucoepidermoid carcinomas. The source of these tumours originates from primary disease in the sinonasal tract and nasopharynx superiorly, and the PPS/deep lobe of parotid inferiorly. Current surgical options available, in suitable selected patient, available in tertiary head and neck cancer hospitals, which have available facilities and staffing is the endoscopic endonasal approach. This approach offers patients a 'complete margin-free surgical excision', minimal complications, shorter hospital stay, and no delay with commencement of any adjuvant treatment compared with the traditional 'open transcutaneous' approach.

SUMMARY

The current evidence specifically to the surgical management of salivary gland malignancy involving the ITF is sparse, with great difficult identifying treated patients and their details among a heterogeneous group of patients with many lesions. There is a need for patient data that have specific pathologic conditions to be amalgamated from such centers and publish on outcome events.

Image-guided endonasal endoscopic excision of Meckel's cave trigeminal schwannoma from cavernous and petrous carotid artery

Trigeminal schwannoma is the second most common schwannoma after vestibular schwannoma. Symptoms vary depending on the anatomical structures affected by the tumor, including facial pain, paresthesia, dizziness and ataxia. The primary goals are controlling the symptoms and the maintenance of cranial nerves’ integrity perioperatively. We report a 39-year-old lady who was complaining of mild right-sided headache, vision and hearing loss, right facial weakness and dysphagia. CT and MRI showed a large dumbbell-shaped tumor originating from the trigeminal fossa abutting the petrous and cavernous carotid artery and extending to the infratemporal fossa. An image-guided endonasal endoscopic removal was successfully done. Image-guided endonasal endoscopic removal of a trigeminal schwannoma abutting the petrous and cavernous carotid artery and extending to the infratemporal fossa is a safe, effective approach, as it offers excellent visualization, accurate localization and safe dissection of the tumor from the critical anatomical neurovascular structures surrounding it.

Surgical management of carcinomas of the infratemporal fossa and skull base: patterns of failure and predictors of long-term outcomes

OBJECTIVE

Infratemporal fossa (ITF) tumors are unique in histological characteristics and difficult to treat. Predictors of patient outcomes in this context are not known. The objective of this study was to identify independent predictors of outcome and to characterize patterns of failure in patients with ITF carcinoma.

METHODS

All patients who had been surgically treated for anterolateral skull base malignancy between 1999 and 2017 at the authors' institution were retrospectively reviewed. Patient demographics, preoperative performance status, tumor stage, tumor characteristics, treatment modalities, and pathological data were collected. Primary outcomes were disease-specific survival (DSS) and local progression-free survival (LPFS) rates. Overall survival (OS) and patterns of progression were secondary outcomes.

RESULTS

Forty ITF malignancies with skull base involvement were classified as carcinoma. Negative margins were achieved in 23 patients (58%). Median DSS and LPFS were 32 and 12 months, respectively. Five-year DSS and OS rates were 55% and 36%, respectively. The 5-year LPFS rate was 69%. The 5-year overall PFS rate was 53%. Disease recurrence was noted in 28% of patients. Age, preoperative performance status, and margin status were statistically significant prognostic factors for DSS. Lower preoperative performance status and positive surgical margins increased the probability of local recurrence.

CONCLUSIONS

The ability to achieve negative margins was significantly associated with improved tumor control rates and DSS. Cranial base surgical approaches must be considered in multimodal treatment regimens for anterolateral skull base carcinomas.

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.

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.

Ultrasonic Scalpel-Assisted Endoscopic Endonasal Surgery of Infratemporal Fossa: Our First Impressions

BACKGROUND

The endoscopic endonasal transpterygoid approach is emerging as a valid option for treating selected tumors in the infratemporal fossa. Compared with traditional open approaches, the endoscopic endonasal approach presents more difficulty in controlling bleeding and less choice in surgical instruments for endoscopic tumor dissection, which is often performed with bipolar forceps or steel dissectors.

CASE DESCRIPTION

We describe the use of an ultrasonic scalpel device for performing endoscopic endonasal resection of 2 rare infratemporal fossa tumors (mature teratoma and hemangiopericytoma), which has not been reported in the literature so far. We also review the literature on endoscopic ultrasonic scalpel use.

CONCLUSIONS

The ultrasonically activated scalpel is a safe, effective and simple to use device, which achieved excellent hemostasis and did not damage adjacent neurovascular structures.

Analysis of the far-medial transoral endoscopic approach to the infratemporal fossa

OBJECTIVES/HYPOTHESIS

To demonstrate anatomic relationships of the far-medial transoral endoscopic assisted approach (FMT-EAA) to the infratemporal fossa (ITF) and define the corridor dimensions, surgical freedom, and limitations associated with this approach.

STUDY DESIGN

Cadaveric study.

METHODS

Twenty ITFs (10 specimens) were dissected with the assistance of 0 °, 30 °, and 45 ° rod-lens endoscopes. Image guidance was used to confirm and measure the corridors' structural boundaries and document the anatomical relationships encountered in this approach.

RESULTS

Access to the ITF via the FMT-EAA can be divided into two secondary surgical corridors: the superomedial and inferolateral triangles, each of which provides access to different areas. The superomedial triangle is bounded medially by the lateral pterygoid plate and posterolateral maxillary sinus wall, superiorly by the greater sphenoid wing, and inferolaterally by the lateral pterygoid muscle. The inferolateral triangle is bounded superiorly by the lower head of the lateral pterygoid muscle, inferiorly by the medial pterygoid muscle, and laterally by the mandible. Using a standard 19-mm endoscope, the FMT-EAA achieves a mean surgical freedom of 231 mm and 161 mm in the vertical and horizontal planes, respectively.

CONCLUSIONS

FMT-EAA adequately exposes critical structures of the ITF. This technique is a viable option for the management of selected ITF lesions, either alone or in combination with alternative minimally invasive approaches to the region.

LEVEL OF EVIDENCE

NA Laryngoscope, 128:2273-2281, 2018.

An unusual foreign body in the infratemporal fossa

Infratemporal fossa injuries are uncommon and often go undetected presenting later with complications. We present a case of an infratemporal fossa penetrating injury with a ball point spring following a vehicular accident. Post-traumatic trismus even following supposedly trivial injury in the area should raise suspicion of possible injury in this location.

Relative Projective Location of Three Bottom Apexes of Petrous Bone on Skull

The complex anatomy of petrous part of temporal bone makes the craniotomy around this area challenging. To avoid damaging the interior structures of petrous part of temporal bone, the authors used computed tomography to get the projection of the petrous part of temporal bone on skulls, making the external contours of petrous part clear, thus protecting its interior structure as a reference in craniotomy. The objective of this study was to find out the three-dimensional location of 4 points of petrous part of temporal bone. Parameters of 120 patients (240 observations) between 25 and 65 years who were free of abnormalities and pathological changes in temporal bone were measured on high-resolution spiral multiple slice computed tomographic multiple planar reconstruction images that were parallel to the base plane. The data were analyzed by SPSS, statistical software with the comparison between sides and sexes. The authors found the accurate locations that 4 points of petrous part of temporal bone with mastoidale as the origin. Then the authors connect the 3 vertexes of underside and the petrous apex and lengthen it until intersect with skulls to get the external landmarks. In the end, the authors get the safe range that can be applied to the clinical surgery.

Application of a computer-aided navigation technique in surgery for recurrent malignant infratemporal fossa tumors

BACKGROUND

Because of the complexity of the local anatomy, tumors in the infratemporal fossa present a great challenge to oral and maxillofacial surgeons. Recurrent malignant tumors in this area are particularly difficult and precarious to resect because scars from previous operations may dislocate some important structures.

METHODS

From August 2010 to December 2013, all recurrent cases of malignant infratemporal fossa tumors at Peking University Stomatological Hospital were enrolled in this study. The patients were divided into 2 groups: the navigation group and the nonnavigation group, with different managements. The following factors were evaluated: operation time, bleeding volume, tumor size, surgical approach and complications, follow-up survey, and outcomes.In addition, survival analyses were performed for all patients.

RESULTS

In total, 42 patients were investigated. The mean operation time for the navigation group was not significantly longer than that of the nonnavigation group (283.64 versus 252.10 min, respectively; P = 0.393); the group's mean intraoperative bleeding volumes were similar (536.36 versus 503.87 mL, respectively; P = 0.814). The surgical approach was determined and categorized as an inferior approach (transmandibular approach, with or without splitting of the mandible), anterior approach (transmaxillary approach), lateral approach (subtemporal-preauricular approach), or combined approach. The inferior approach was most frequently used in both groups (ie, 63.6% for the navigation group and 80.6% for the nonnavigation group). The tumors were completely resected in 4 patients from the navigation group and 24 patients from the nonnavigation group. Regarding complications in the navigation and nonnavigation groups, the incidence was not significantly different (27.2% versus 41.9%, respectively; P = 0.485). The 3-year survival for patients in the navigation group was 71.6% compared with 52.9% in the nonnavigation group, with no significant difference. In the survival analysis, no significant factor was determined.

CONCLUSIONS

A computer-aided navigation technique has been successfully introduced to resect infratemporal fossa tumors and was successfully applied to the resection of recurrent malignant tumors. This new technique alone does not determine the outcome of patients with recurrent malignant infratemporal fossa tumors. Although some improvements are necessary, the visible navigation during surgery could increase the accuracy and safety of the operations and enhance surgeon confidence.

Surgical Management of a Functional Paraganglioma of the Infratemporal Fossa

Background Paragangliomas are rare neural crest tumors that can manifest in the head and neck as either functional or more commonly as nonfunctional lesions. Paragangliomas of the infratemporal fossa are exceedingly rare, with no more than a handful of documented cases. Like other tumors of this space, surgical management is challenging on account of complex anatomy and nearby critical structures.

Methods A 44-year-old man presented with a right infratemporal fossa functional paraganglioma. Following preemptive embolization and autonomic pharmacotherapy, his tumor was successfully resected via a transfacial maxillary swing approach.

Results This case highlights the surgical management of a functional paraganglioma of the infratemporal fossa while demonstrating the effectiveness of a transfacial maxillary swing approach for both exposure and resection.

Conclusion Although this report summarizes much of the literature on paragangliomas, there is still much to uncover regarding the fundamental features and genetic etiology of these lesions.

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.

Endoscopic versus Open Approach to the Infratemporal Fossa: A Cadaver Study

Introduction Various lateral and anterior approaches to access the infratemporal fossa (ITF) have been described. We provide our observations regarding the endoscopic transpterygoid and preauricular subtemporal approaches, listing their respective advantages and limitations through cadaveric dissection. Methods A cadaver study was performed on five adult specimens. An endoscopic transpterygoid approach to the ITF was completed bilaterally in three specimens, and an open preauricular ITF approach was performed bilaterally in two specimens. Results After completing the cadaveric dissections, we studied differences between the endoscopic transpterygoid approach and open preauricular subtemporal approaches in regard to exposure and ease of dissection of different structures in the ITF. Conclusions In comparison with a lateral approach, the endonasal endoscopic transpterygoid approach provides better visualization and more direct exposure of median structures such as the nasopharynx, eustachian tube, sella, and clivus. We concluded that the endoscopic transpterygoid approach can be utilized to resect benign lesions and some select group of malignancies involving the infratemporal and middle cranial fossae. Open approaches continue to play an important role, especially in the resection of extensive malignant tumors extending to these regions.

3D printed reproductions of orbital dissections: a novel mode of visualising anatomy for trainees in ophthalmology or optometry

BACKGROUND

The teaching of human head, neck and orbital anatomy forms a critical part of undergraduate and postgraduate medical and allied health professional training, including optometry. While still largely grounded in cadaveric dissection, this method of instruction is constrained in some countries and regional areas by access to real human cadavers, costs of cadaver bequest programmes, health and safety of students and staff and the shortage of adequate time in modern curricula. Many candidates choosing a postgraduate pathway in ophthalmological training, such as those accepted into the Royal Colleges of Ophthalmology in the UK, Australia and New Zealand programmes and the American Academy of Ophthalmologists in the USA, are compelled as adult learners to revise or revisit human orbital anatomy, ocular anatomy and select areas of head and neck anatomy. These candidates are often then faced with the issue of accessing facilities with dissected human cadaveric material.

METHODS

In light of these difficulties, we developed a novel means of creating high-resolution reproductions of prosected human cadaver orbits suitable for education and training.

RESULTS

3D printed copies of cadaveric orbital dissections (superior, lateral and medial views) showing a range of anatomical features were created.

DISCUSSION

These 3D prints offer many advantages over plastinated specimens as they are suitable for rapid reproduction and as they are not human tissue they avoid cultural and ethical issues associated with viewing cadaver specimens. In addition, they are suitable for use in the office, home, laboratory or clinical setting in any part of the world for patient and doctor education.

Endoscopic transoral and transmaxillary excision of the infratemporal fossa hemangioma

Hemangiomas in the infratemporal fossa (ITF) are extremely rare benign vascular tumors. For many tumors of the ITF, with the exception of some small hemangiomas, a lateral facial approach has often been required. Recently, however, there have been some reports that minimally invasive endoscopic surgery can be used in the ITF; this would reduce the risk of surgical complications. To date, there has been no report of a hemangioma of the ITF exceeding 6 cm being resected by the endoscopic approach without facial incisions. Here, however, we report two cases of ITF hemangiomas that were completely extracted endoscopically, using a transmaxillary and transoral approach, without facial incisions or surgical complications.

The production of anatomical teaching resources using three-dimensional (3D) printing technology

The teaching of anatomy has consistently been the subject of societal controversy, especially in the context of employing cadaveric materials in professional medical and allied health professional training. The reduction in dissection-based teaching in medical and allied health professional training programs has been in part due to the financial considerations involved in maintaining bequest programs, accessing human cadavers and concerns with health and safety considerations for students and staff exposed to formalin-containing embalming fluids. This report details how additive manufacturing or three-dimensional (3D) printing allows the creation of reproductions of prosected human cadaver and other anatomical specimens that obviates many of the above issues. These 3D prints are high resolution, accurate color reproductions of prosections based on data acquired by surface scanning or CT imaging. The application of 3D printing to produce models of negative spaces, contrast CT radiographic data using segmentation software is illustrated. The accuracy of printed specimens is compared with original specimens. This alternative approach to producing anatomically accurate reproductions offers many advantages over plastination as it allows rapid production of multiple copies of any dissected specimen, at any size scale and should be suitable for any teaching facility in any country, thereby avoiding some of the cultural and ethical issues associated with cadaver specimens either in an embalmed or plastinated form.

Clinical correlates of the anatomical relationships of the foramen ovale: a radioanatomical study

Introduction Endonasal endoscopic transpterygoid approaches are commonly used techniques to access the infratemporal fossa and parapharyngeal space. Important endoscopic endonasal landmarks for the poststyloid parapharyngeal space, hence the internal carotid artery, include the mandibular nerve at the level of foramen ovale and the lateral pterygoid plate. This study aims to define the anatomical relationships of the foramen ovale, establishing its distance to other important anatomical landmarks such as the pterygoid process and columella. Methods Distances between the foramen ovale, foramen rotundum, and fixed anatomical landmarks like the columella and pterygoid process were measured using computed tomography (CT) scans and cadaveric dissections of the pterygopalatine and infratemporal fossae. Results The mean distances from the foramen ovale to columella and from the foramen rotundum to columella were found to be 9.15 cm and 7.09 cm, respectively. Analysis of radiologic measurements detected no statistically significant differences between sides or gender. Conclusions The pterygoid plates and V3 are prominent landmarks of the endonasal endoscopic approach to the infratemporal fossa and poststyloid parapharyngeal space. A better understanding of the endoscopic anatomy of the infratemporal fossa and awareness of the approximate distances and geometry among anatomical landmarks facilitates a safe and complete resection of lesions arising or extending to these regions.

A novel method for intraoral access to the superior head of the human lateral pterygoid muscle

Background. The uncoordinated activity of the superior and inferior parts of the lateral pterygoid muscle (LPM) has been suggested to be one of the causes of temporomandibular joint (TMJ) disc displacement. A therapy for this muscle disorder is the injection of botulinum toxin (BTX), of the LPM. However, there is a potential risk of side effects with the injection guide methods currently available. In addition, they do not permit appropriate differentiation between the two bellies of the muscle. Herein, a novel method is presented to provide intraoral access to the superior head of the human LPM with maximal control and minimal hazards. Methods. Computational tomography along with digital imaging software programs and rapid prototyping techniques were used to create a rapid prototyped guide to orient BTX injections in the superior LPM. Results. The method proved to be feasible and reliable. Furthermore, when tested in one volunteer it allowed precise access to the upper head of LPM, without producing side effects. Conclusions. The prototyped guide presented in this paper is a novel tool that provides intraoral access to the superior head of the LPM. Further studies will be necessary to test the efficacy and validate this method in a larger cohort of subjects.

Topography, syntopy and morphology of the human otic ganglion: a cadaver study

The human otic ganglion (OG) is not readily accessible during ordinary anatomical teaching courses because of insufficient time and severe difficulties encountered in dissection. Accordingly, most anatomical descriptions of its location, relation to neighbouring structures, size and shape are supported only by drawings, but not by photographs. The aim of this study has been to present the OG with associated roots and branches in dissected anatomic specimens. Following cumbersome dissection and precise photo-documentation, a detailed analysis of location, syntopy and morphology was performed. We carried out this study in 21 infratemporal fossae of 18 cadavers and were able to identify the OG, the mandibular-, the inferior alveolar- and the lingual nerve in all of them. We found no significant variation regarding the location of the GO in the infratemporal fossa and its syntopy to the adjacent structures. An OG resembling the classic description was found only in 90.50% of the cases. All 3 roots (parasympathetic, sympathetic and sensory) could be identified only in 82.3% of the specimens. The established presence of ganglionic branches varied from 0% (communicating rami to the meningeal branch of the mandibular nerve, to the greater petrosal nerve and to the lingual nerve) to 90% (r. communicans to n. canalis pterygoideus). We conclude that precise knowledge of this enormous variety might be very helpful not only to students of medicine and dentistry during anatomical dissection courses, but also to head and neck surgeons, ear-nose-throat specialists and neurosurgeons when treating pathology of pre- and postganglionic fibres.

Volumetry and analysis of anatomical variants of the anterior portion of the petrous apex outlined by the kawase triangle using computed tomography

Background Anterior petrosectomy has become an increasingly used approach for petroclival lesions. This study measures the volume and the anatomical variants of the anterior portion of the petrous apex outlined by the Kawase triangle using computed tomography (CT). Methods This was a transversal retrospective study. We assessed the anterior petrous apex portion outlined by the Kawase triangle in consecutive patients > 18 years of age from CT scans of temporal bone stored in an archive system. The volumetry was performed on a workstation. Results A total of 154 petrosal apex were analyzed in 77 patients (36 men). The average volume of the region outlined by the Kawase triangle was 1.89 ± 0.52 cm(3). The volume average in men was 2.01 ± 0.58 cm(3), and the average in women was 1.79 ± 0.41 cm(3). Intra- and interobserver agreement were both excellent, and there was little variance. Nineteen petrous apex demonstrated anatomical variations. In 18 cases it was pneumatized, and in one case a vascular or nerve-like structure was identified, a report we did not find in the literature. Conclusion The volumetry of the petrous apex anterior portion outlined by the Kawase triangle can be made by CT with excellent intra- and interobserver agreement and reproducibility. There are anatomical variants in this region that are relevant to surgery.

[Three-dimensional endoscopic endonasal study of skull base anatomy]

INTRODUCTION

Training in dissection of the paranasal sinuses and the skull base is essential for anatomical understanding and correct surgical techniques. Three-dimensional (3D) visualisation of endoscopic skull base anatomy increases spatial orientation and allows depth perception.

OBJECTIVE

To show endoscopic skull base anatomy based on the 3D technique.

METHODS

We performed endoscopic dissection in cadaveric specimens fixed with formalin and with the Thiel technique, both prepared using intravascular injection of coloured material. Endonasal approaches were performed with conventional 2D endoscopes. Then we applied the 3D anaglyph technique to illustrate the pictures in 3D.

RESULTS

The most important anatomical structures and landmarks of the sellar region under endonasal endoscopic vision are illustrated in 3D images.

CONCLUSION

The skull base consists of complex bony and neurovascular structures. Experience with cadaver dissection is essential to understand complex anatomy and develop surgical skills. A 3D view constitutes a useful tool for understanding skull base anatomy.

Unique variation in the course of maxillary artery in infratemporal fossa: a case report

Maxillary artery is one of the key contents of the infratemporal fossa. Mandibular nerve and its branches form a clinically important relation of maxillary artery in this region. A comprehensive knowledge of variations of maxillary artery in the fossa is of special relevance in oral maxillofacial surgeries, management of epistaxis, intractable neuralgias or headaches. We found a unique variation of maxillary artery, presenting bilaterally, in relation to branches of mandibular nerve. During routine dissection in a 55-year-old male cadaver, maxillary artery was seen passing deep to lateral pterygoid muscle and crossed through the nerve loop formed between two roots of auriculotemporal nerve and posterior division of mandibular nerve. Further course of maxillary artery was medial to the posterior division of mandibular nerve. Maxillary artery gave its middle meningeal artery branch as it traversed through the nerve loop. A tortuous course taken by maxillary artery can lead to its entrapment causing headaches or nerve irritation presenting with neuralgia.

Endoscopic endonasal access to the jugular foramen: defining the surgical approach

Introduction The endoscopic endonasal approach to the parapharyngeal space (PPS) and jugular foramen is not well defined. We sought to systematically define the important landmarks and limitations of this new surgical technique using an endoscopic transmaxillary transpterygoid corridor. Methods Endoscopic dissection was performed in both sides of two latex-injected cadaver heads. Left-sided dissections were facilitated by the addition of a sublabial maxillary antrostomy. The pterygopalatine fossa, infratemporal fossa, and PPS were sequentially dissected and the endoscopic perspective was examined. Measurements were obtained from the surgical orifices to the upper cervical internal carotid artery (ICA) and internal jugular vein (IJV). Results Successful access to the PPS and jugular foramen was achieved in each dissection. The lateral pterygoid plate, mandibular branch of the trigeminal nerve, middle meningeal artery, levator veli palatini muscle, Eustachian tube, and stylopharyngeal fascia were identified as landmarks for the upper cervical ICA and the IJV. The mean distance from the nasal sill was markedly greater than from an ipsilateral sublabial antrostomy. Conclusion The endoscopic endonasal approach can provide adequate access to the PPS, carotid sheath, and jugular foramen. Multiple landmarks are useful to guide the dissection within these deep spaces and may facilitate the clinical application of this approach.

Large trigeminal schwannoma of the infratemporal fossa: evaluation of neoangiogenesis in this rare neoplasm

BACKGROUND

Trigeminal schwannomas are uncommon intracranial tumors. Extracranial trigeminal schwannomas in the infratemporal fossa are rare.

METHODS

We present a case with a clinical history of facial pain. MRI and CT scans showed a mass arising from the infratemporal fossa extending into the intracranial space.

RESULTS

We performed a combined neurosurgical and maxillofacial approach with preoperative endovascular embolization. Complete removal of the parasellar component was achieved with a minimal extracranial neoplastic residual. High microvessel density, reflecting intense neoangiogenesis, was detected through the immunohistochemical staining with endoglin.

CONCLUSIONS

Due to the unique development pattern of trigeminal schwannoma involving multiple intracranial fossae and extracranial compartment, we chose a combined neurosurgical and maxillofacial approach with preoperative embolization of the tumor. Immunohistochemical findings suggest that the extensive growth observed may be related to an intense neoangiogenesis, opening the perspective to novel therapeutic options based on the inhibition of neoangiogenesis.

Management of Head and Neck Paragangliomas: A Series of 9 Cases and Review of the Literature

We conducted a retrospective study of the long-term functional results of surgery for head and neck paragangliomas. Our study population was made up of 9 patients—4 men and 5 women, aged 22 to 59 years (mean: 46.6; median: 51)—who had undergone surgical excision of a head and neck paraganglioma from January 2002 through December 2006 in the ENT Department at Pugliese-Ciaccio Hospital in Catanzaro, Italy. Of the 9 paragangliomas, 4 were carotid body tumors, 2 were glomus tympanicum tumors, and 3 were glomus vagale tumors. None of the cases was bilateral or hereditary. Complete tumor resection was achieved in 8 patients; in the remaining patient, a small amount of intradural residual vagus nerve paraganglioma had to be left in situ. The internal carotid artery was preserved in all 4 resections of carotid body tumors. There was only 1 case of postoperative lower cranial nerve deficits, which occurred in a patient with a carotid body tumor. Follow-up ranged from 12 to 53 months (mean: 37.2; median: 36), and no recurrences were documented. Our small sample showed that surgical treatment of head and neck paragangliomas provided excellent tumor control with low postoperative morbidity, even in patients with large tumors. A wait-and-scan policy may be more appropriate for patients at an advanced age or who are otherwise at high surgical risk, as well as for those whose tumors have recurred following radiotherapy.

Anatomia microcirúrgica das artérias infratentoriais: um estudo estereoscópico

CONTEXTO: O espaço infratentorial do crânio é uma região que possui complexa rede de artérias que vascularizam o tecido cerebelar e o tronco encefálico. Sua complexa anatomia tridimensional deve ser profundamente entendida pelo neurocirurgião vascular e pelo radiologista intervencionista. OBJETIVO: Descrever as principais artérias do espaço infratentorial e seu trajeto, bem como sua relação com a topografia das estruturas neurais. MÉTODOS: Foram estudados 30 cérebros humanos, fixados em formalina e 6 cabeças de cadáveres dissecadas, utilizando-se microscópico cirúrgico com 3X a 40X de aumento. Os cérebros e todas as cabeças foram injetados com siloxanos polimerizados ou polisiloxanos (silicone) colorido. As dissecções anatômicas foram documentadas utilizando-se técnica para obtenção de imagens tridimensionais (3D), objetivando a produção de impressões estereoscópicas. RESULTADOS: São descritos o trajeto, segmentos e ramos das artérias basilar, cerebelar superior, cerebelar anteroinferior, cerebelar posteroinferior e vertebral. CONCLUSÃO: A anatomia das artérias infratentoriais é complexa e as imagens estereoscópicas apresentadas são um importante instrumento de documentação, pois permitem uma noção de profundidade da anatomia estudada.

[Transzygomatic pterional approach. Part 2: Surgical experience in the management of skull base pathology]

OBJECTIVES

To present our experience with the transzygomatic pterional approach in the treatment of neurosurgical pathology of the base of the skull located in the middle cranial fossa and surrounding areas.

METHOD

A retrospective study of pathological findings, surgical outcomes and complications in a series of 31 cases operated on between 2009 and 2011 using a transzygomatic pterional approach.

RESULTS

The lesions involved the sphenoid wing (25.9%), several regions due to invasive growth pattern (19.5%), the temporal lobe (16.1%) and cavernous sinus (12.9%). The others were located in the floor of the middle fossa, Meckel's cave, incisural space, cisterns and infratemporal region. The pathological nature of the lesions was: benign meningioma (42%), temporal lobe tumour (19.5%), vascular disease (12.9%), inflammatory lesions (6.4%), atypical meningioma (6.4%), epidermoid cyst (6.4%), neurinoma (3.2%) and poorly differentiated infratemporal carcinoma (3.2%). The approach was usually combined extra-intradural (58.1%) and, less frequently, just extradural (16.1%) or intradural (25.8%). Approach-related complications were minor: haematomas in the wound not requiring treatment (67.8%), superior transient facial paresis (9.7%), transient temporomandibular joint dysfunction (12.9%) and atrophy of the temporal muscle (16.2%). There were no hardware-related complications or cosmetic issues related to the osteotomy and posterior osteosynthesis of the zygomatic arch.

CONCLUSIONS

The pterional approach combined with osteotomy of the zygomatic arch allows mobilising the temporalis muscle away from the temporal fossa, consequently exposing its entire surface to complete the temporal craniotomy up to the middle fossa; it helps to access and treat pathology in this region or it can be used as a corridor to approach surrounding areas.