Endoscopic Endonasal Transpterygoid Approach: Technical Lessons

INDICATIONS CORRIDOR AND LIMITS OF EXPOSURE

The endoscopic endonasal transpterygoid approach (EETPA) provides direct access to the petrous apex, lateral clivus, inferior cavernous sinus compartment, jugular foramen, and infratemporal fossa. 1,2 In the coronal plane, it provides exposure far beyond a traditional sphenoidotomy.

ANATOMIC ESSENTIALS NEED FOR PREOPERATIVE PLANNING AND ASSESSMENT

The pterygoid process of the sphenoid bone forms the junction between the body and greater sphenoid wing before bifurcating because it descends into medial and lateral plates. The key to this exposure lies in the region's bony foramina: the palatovaginal canal, vidian canal, and foramen rotundum. 3.

ESSENTIALS STEPS OF THE PROCEDURE

After performing a maxillary antrostomy, stepwise exposure of these foramina leads to the pterygopalatine fossa. The sphenopalatine artery is cauterized as it becomes the posterior septal artery at the sphenopalatine foramen, and the maxillary sinus' posterior wall is opened to expose the pterygopalatine fossa. After mobilizing and retracting the contents of the pterygopalatine fossa, the pterygoid process is removed, improving access in the coronal plane. 4.

PITFALLS/AVOIDANCE OF COMPLICATIONS

Vidian neurectomy causes decreased or absent lacrimation. Injury to the maxillary nerve or its branches results in facial, palatal, or odontogenic anesthesia or neuralgia. In addition, the EEPTA precludes the ability to raise an ipsilateral nasal septal flap, making it crucial to plan reconstruction preoperatively. 4,5.

VARIANTS AND INDICATIONS FOR THEIR USE

There are 5 variants of the EEPTA: extended pterygopalatine fossa, lateral recess of the sphenoid sinus, petrous apex, infratemporal fossa and petrous carotid artery, and middle and posterior skull base. 5The patient consented to the procedure.Images in the video used with permission as follows: images at 0:33 and 1:15 reused from Bozkurt et al, 3 © Georg Thieme Verlag KG; image at 0:39 from Prosser et al, 5 © John Wiley and Sons; images at 0:54, 9:03, and 9:38 from Kasemsiri et al, 1 © John Wiley and Sons; images at 1:07 and 9:44 from Falcon et al, 2 © John Wiley and Sons; image at 1:15 from Sandu et al, 4 © Springer Nature.

Microanatomic Study of the Optic Canal

BACKGROUND

The continuous development of microsurgical techniques to treat lesions in and around the optic canal (OC) emphasizes the need for an accurate understanding of the microanatomy of the region.

METHODS

Forty anatomic specimens were studied, with emphasis on the OC. The sphenoid bone and related structures were decalcified, added to animal gelatin, cut into 1-mm thick slices, and observed through a surgical microscope. The OC was considered the course that contained exclusively the optic nerve (ON) and ophthalmic artery.

RESULTS

The mean distance between the medial walls of the OC was 12.2 mm, and the OC had an average length of 12.06 mm. The OC has a horizontal oval shape in the proximal (internal) segment; a round shape in the middle segment; and a vertical oval shape in the distal (external) segment at the orbital cavity. In the middle segment of the OC, the thickest wall of the OC was the lateral (average: 0.68 mm), while the medial, inferior, and superior wall measures had averages of 0.75, 0.40, and 0.39 mm, respectively. The lateral wall of the sphenoid sinus is located under the OC, and the inferior wall of the OC separates both structures. The ophthalmic artery inside the OC was always located under the ON, between the dural sheaths, and had an average diameter of 1.03 mm.

CONCLUSIONS

The neurovascular structures within the OC vary in size and shape. The anatomic knowledge of the OC and its variations allows better surgical results and minimizes the surgical morbidity.

Anatomic Nuances of the Ophthalmic Artery Origin from a Ventral Viewpoint: Considerations and Implications for Endoscopic Endonasal Surgery

BACKGROUND

The origin of the ophthalmic artery is within the surgical field of endoscopic endonasal approaches (EEAs) to the suprasellar and parasellar regions. However, its anatomy from the endoscopic point-of-view has not been adequately elucidated.

OBJECTIVE

To highlight the anatomy of the ophthalmic artery origin from an endoscopic endonasal perspective.

METHODS

The origin of the ophthalmic artery was studied bilaterally under endoscopic visualization, after performing transplanum/transtubercular EEAs in 17 cadaveric specimens (34 arteries). Anatomic relationships relevant to surgery were evaluated. To complement the cadaveric findings, the ophthalmic artery origin was reviewed in 200 "normal" angiographic studies.

RESULTS

On the right side, 70.6% of ophthalmic arteries emerged from the superior aspect, while 17.6% and 11.8% emerged from the superomedial and superolateral aspects of the intradural internal carotid artery, respectively. On the left, 76.5%, 17.6%, and 5.9% of ophthalmic arteries emerged from the superior, superomedial, and superolateral aspects of the internal carotid, respectively. Similar findings were observed on angiography. All ophthalmic arteries emerged at the level of the medial opticocarotid recess. Overall, 47%, 26.5%, and 26.5% of ophthalmic arteries (right and left) were inferolateral, inferior, and inferomedial to the intracranial optic nerve segment, respectively. On both sides, the intracranial length of the ophthalmic artery ranged from 1.5 to 4.5 mm (mean: 2.90 ± standard deviation of 0.74 mm).

CONCLUSION

Awareness of the endoscopic nuances of the ophthalmic artery origin is paramount to minimize the risk of sight-threatening neurovascular injury during EEAs to the suprasellar and parasellar regions.

Anatomic study of the distance between the articular eminence and foramen spinosum and foramen spinosum and petrotympanic fissure

PURPOSE

The middle meningeal artery is in close proximity to the medial aspect of the temporomandibular joint (TMJ). A major potential complication of surgery in the area of the TMJ is possible severance of the middle meningeal artery. An understanding of the relationship of the middle meningeal artery to easily identifiable landmarks lateral to the TMJ can help prevent the complications associated with TMJ surgery. The aim of the present study was to define the location of the middle meningeal artery by relating the distance between the easily identifiable bony landmarks of the articular eminence, petrotympanic fissure, and foramen spinosum.

MATERIALS AND METHODS

Using a cross-sectional study design, we selected dried skulls from the Hamman-Todd skeleton collection at the Cleveland Museum of Natural History that were older than 20 years of age at death. The primary study variables were the distances between the articular eminence and foramen spinosum and the foramen spinosum and petrotympanic fissure. To appropriately analyze the variables, stratifications of age, gender, race, and anatomic location were applied. To measure the relationship between the stratifications and distances, a multivariate analysis of variance test was performed. The statistical results were deemed significant at P < .05.

RESULTS

The sample consisted of 354 skulls or a total of 708 complexes. In analyzing the data, we noted that the only stratifications that bore any statistical significance were gender, with P < .0001, and the race-distance correlation, with a P value of .0007.

CONCLUSIONS

The results of the present study suggest a definite difference in regard to gender on the distance between both sets of anatomic landmarks. Future studies could be tailored to further explore the effect of age on the distance, as a slight correlation was noted in our study.

The anatomical relations of the sphenoid sinus and their implications in sphenoid endoscopic surgery

Alongside the past development of endoscopic sinus surgery, knowledge about the anatomy of the sinuses has become crucial for surgeons. The sphenoid sinus is one of the most variable of all sinuses. Its relations to vital vascular and nervous elements make its approach a challenge for endoscopic surgeons. These relations include the internal carotid artery, the optic nerve, the pituitary gland, the Vidian nerve, and other vascular and nervous elements depending on the size of the sinus. This paper will make a review of these anatomical relations and their importance in endoscopic sphenoid surgery.

Vascular connections of the lateral wall of the sinus: surgical effect in sinus augmentation

PURPOSE

There are several vascular vessels that supply the maxillary sinus, such as the posterior superior alveolar artery, the anterior superior alveolar artery, and the infraorbital artery (IOA). These vessels have to be taken into consideration during a sinus augmentation because of the potential risk of bleeding during the procedure. The objective of this investigation was to study variations in maxillary sinus artery connections with the potential surgical effect during a sinus floor elevation by the lateral wall.

MATERIALS AND METHODS

The first part of the study was done in 32 anatomical specimens embedded in 10% formaldehyde solution and aged between 55 and 70 years (mean, 61.3 years). The second part of the study was a radiographic study using computerized tomographic (CT) scan images in 35 randomized patients treated in odontology and maxillofacial surgery departments.

RESULTS

Results were recorded for 134 sinuses. In most cases, there was no vessel visible or no vessel present with a diameter less than 0.5 mm after dissection or CT-scan analysis: 120 sinuses (89.5%). In 14 cases (10.5%) there were vessels in the lower two thirds of the anterolateral wall. In 10 sinuses (71.4% of the 14 cases), there was an intraosseous or intrawall artery and in 2 sinuses (14.3%) they were in the intrasinusal position. In 8 of the 14 sinuses (57.1%, about 6% of overall sinuses) the diameter was between 1 and 2.5 mm.

CONCLUSION

Knowledge of the arterial supply is essential for surgical treatment in the sinus area. A CT scan is recommended and the radiologist must be advised to search for intraosseous or extraosseous vessels in the lower two thirds of the maxillary sinus.

Acquisition of surgical skills for endonasal skull base surgery: a training program

INTRODUCTION

Endonasal surgery represents a radical change in the practice of cranial base surgery and requires the acquisition of new knowledge and surgical skills. The optimal training program for surgeons has not been established.

METHODS

We reviewed our experience with endonasal cranial base surgery from 1998 to 2006 to develop a training plan for the acquisition of surgical skills. It consists of a modular and incremental approach to endonasal skull base surgery that is designed to train surgeons to function as a team, learn endoscopic skull base anatomy, and develop fundamental endoscopic skills.

RESULTS

Stages of training are established for the otolaryngologist-head and neck surgeon and the neurosurgeon that are based on level of technical difficulty, potential risk of vascular and neural injury, and unfamiliar endoscopic anatomy. Mastery of each level is recommended before attempting procedures at a higher level.

CONCLUSIONS

Standardization of training and the adoption of a modular, incremental training program are expected to facilitate the training of endonasal surgeons in both surgical specialties. Adherence to such a program during the growth phase of endoscopic skull base surgery may decrease the risk of complications as the surgeon's knowledge and surgical expertise develop.

The Pterygopalatine Fossa

The pterygopalatine fossa (PPF) is a small anatomic region of particular interest in cranial base surgery. Infectious diseases and malignancy may spread through the PPF to contiguous areas as a result of the low resistance offered by the numerous foramina and fissures that surrounds the fossa. We present an anatomic report on the PPF. Twelve sides of six fixed cadaveric heads were dissected through a LeFort I maxillary osteotomy with transantral exposure of the neurovascular content of the PPF. Arterial vascular patterns of the maxillary artery were observed. The pterygopalatine fossa is a deeply located small anatomic region with a rich neurovascular content. The third portion of the maxillary artery in the PPF may demonstrate a variable vascular morphology. A correct understanding and knowledge of the anatomic structures lodged into the PPF, as well as their relationships and functions, remain crucial to minimizing postsurgical morbidity and intraoperative complications.

Orbital wall infarction mimicking periorbital cellulitis in a patient with sickle cell disease

Orbital wall infarction and subperiosteal haematomas are unusual manifestations of sickling disorders. Here we report an 11-year-old girl with sickle cell anaemia having multiple skull infarctions including the orbital bony structures associated with subperiosteal haematomas. The diagnosis was made by MRI, which showed bone marrow changes and associated haemorrhagic collections. The patient was successfully managed without surgical intervention.

Endoscopic sphenopalatine artery ligation--when, why and how to do it. An on-line video tutorial

KEYPOINTS: Endoscopic ligation of the sphenopalatine artery (ESPAL) has recently become the treatment of choice for refractory epistaxis. This paper reviews the background, indications and potential complications of ESPAL. The main focus of this article is an online video tutorial on the anatomy and surgical technique of ESPAL. Web links lead to video clips of operative steps and therefore this paper should be read in front of a computer with access to the Internet. To study the techniques the links detailed below should be followed. (For computers running RealPlayer software the .wmv extension in each of these links should be replaced with the .rm extension.) * Incision, http://nhsgg.org.uk/content/streams/Figure3.wmv * Flap elevation, http://nhsgg.org.uk/content/streams/Figure4.wmv * Pedicle location, http://www.nhsgg.org.uk/content/streams/Figure5.wmv * Clip application, http://www.nhsgg.org.uk/content/streams/Figure6.wmv.

The morphology and morphometry of the foramina of the greater wing of the human sphenoid bone

The greater wing of the human sphenoid bone is pierced by several foramina, which contain, as a main element, the venous anastomoses between the interior of the skull and the extracranial veins. Since data concerning these foramina are scarce in the literature, studies comprising the frequency of occurrence and morphology of the foramina of the greater wing of the human sphenoid bone were undertaken on 100 macerated skulls. We found that the foramen ovale is divided into 2 or 3 components in 4.5% of cases. Moreover, the borders of the foramen ovale in some skulls were irregular and rough. This may suggest, on radiological images, the presence of morbid changes, which might be the sole anatomical variation. Concurrent with the foramen ovale are accessory foramina. The foramen of Vesalius and the cavernous foramen were present in 17% and 33% of cases, respectively. The foramen of Vesalius was always single and the cavernous foramen also occurred in multiple form. The foramen spinosus and the foramen rotundum occurred as permanent elements of the skulls studied. The mean area of the foramina measured, excluding the foramen ovale, was not considerable, which may suggest that they play a minor role in the dynamics of blood circulation in the venous system of the head.

Endoscopic electrosurgical management of posterior epistaxis: shifting paradigm

Recent literature has embraced the use of electrosurgery, sphenopalatine vascular clipping, and endoscopy in posterior epistaxis. With the advent of endoscopy, the surgical treatment of posterior epistaxis has shifted from internal maxillary ligation to endoscopic sphenopalatine artery control. This article introduces an endoscopic electrosurgical approach for patients suffering from idiopathic posterior epistaxis that combines one or more of the following methods: endoscopic selective branch cauterization, endoscopic sphenopalatine artery cautery, and endoscopic posterior nasal cauterization. This approach is currently used in a hospital-based community otolaryngology practice and is presented from a Canadian health care perspective (Quebec). This article presents the experience in a series of 17 patients treated during a 35-month period and prospectively followed and discusses the surgical technique, patients' outcome, and the implications of such a practice.

Early Operative Intervention versus Conventional Treatment in Epistaxis: Randomized Prospective Trial

OBJECTIVE

This prospective randomized trial was designed to compare intranasal endoscopic sphenopalatine artery ligation (ESAL) with conventional nasal packing in the treatment of recurrent epistaxis.

METHODS

Patients were registered in the study databank following referral for epistaxis control to the otolaryngology service at the University of Alberta. All patients were initially packed using Merocel (Xomed Surgical Products, Jacksonville, FL) nasal dressings bilaterally. Patients were enrolled in the study following failure of Merocel packings. Informed consent was obtained in accordance with the Health Research Ethics Board. The patients were then managed with Vaseline nasal packs or ESAL. Patient demographics, treatment characteristics, number of hospitalization days, and rates of recurrence were recorded prospectively. The total cost of treatment for each patient was calculated.

RESULTS

Nineteen patients were enrolled in the study. There was a significant reduction in cost and length of hospitalization of the patients undergoing ESAL compared with the conventional nasal packings. ESAL was also 89% effective in controlling the bleeding and had minimal sequelae or complications. The overall calculated cost of patients undergoing ESAL was dollars 5133 compared with dollars 12213 in the conservative group, resulting in an average saving of dollars 7080 per patient. There was overwhelming patient satisfaction with ESAL compared with nasal packings.

CONCLUSION

ESAL is an excellent, well-tolerated, and cost-effective method of treating recurrent epistaxis.

The clinical anatomy of the maxillary artery in the pterygopalatine fossa

PURPOSE

The purposes of this study were to delineate the maxillary artery and its branching arteries and to develop a classification of the various branching patterns by means of serial cadaver dissections of the pterygopalatine fossa region.

MATERIALS AND METHODS

Fifteen Korean adult cadavers were used; 2 sides of each cadaver were examined, for a total of 30 sides. Before dissection of the pterygopalatine region, computed tomography scan was taken of 20 cadaver heads. Sectioned specimens of 9 sides of the cadaver heads in 3.0-mm thickness were made for this study. Then we dissected 21 sides of fresh cadavers under the microscope. In this investigation, we observed branching patterns of the third portion of the maxillary artery, a relationship of the terminal branches of the maxillary artery to the pterygomaxillary junction, and the course of descending palatine artery. Then we classified the branching patterns of the maxillary artery in the pterygopalatine fossa.

RESULTS

From the pterygomaxillary junction to the pterygopalatine fossa region, the maxillary artery was usually branched into 5 arteries in the following order: posterior superior alveolar artery, infraorbital artery, artery of the pterygoid canal, descending palatine artery, and sphenopalatine artery. Of 21 cadavers, 18 showed this order (85.7%). There were 2 types of branching patterns of the posterior superior alveolar artery and the infraorbital artery. The average distance from the most inferior point of the pterygomaxillary junction to the posterosuperior alveolar artery, infraorbital artery, and descending palatine artery was 15.2, 32.2, and 24.8 mm, respectively. In most cases (95.2%), the greater and lesser palatine arteries were divided from the short descending palatine artery. According to the contours of the third portion of the maxillary artery, we classified them into 5 types: the "Y" type (19%), "intermediate" type (33.3%), "T" type (23.8%), and "M" type (14.3%).

CONCLUSION

The results of this investigation show the common patterns of the maxillary artery.

Microsurgical anatomic features and nomenclature of the paraclinoid region

OBJECTIVE

We describe the detailed microsurgical anatomic features of the clinoid (C5) segment of the internal carotid artery (ICA) and surrounding structures, clarify the anatomic relationships of structures in this region, and emphasize the clinical relevance of these observations. Furthermore, because the nomenclature of the paraclinoid region is confusing and lacks standardization, this report provides a glossary of terms that are commonly used to descibe the anatomic features of the paraclinoid region.

METHODS

The region surrounding the anterior clinoid process was observed in 70 specimens from 35 formalin-fixed cadaveric heads. Detailed microanatomic dissections were performed in 10 specimens. Histological sections of this region were obtained from the formalin-fixed cadaveric specimens.

RESULTS

The clinoid segment of the ICA is the portion that abuts the clinoid process. This portion of the ICA can be directly observed only after removal of the clinoid process. The dura of the cavernous sinus roof separates to enclose the clinoid process. The clinoid segment of the ICA exists only where this separation of dural layers is present. Because the clinoid process does not completely enclose the ICA in most cases, the clinoid segment is shaped more like a wedge than a cylinder. The outer layer of the dura (dura propria) is a thick membrane that fuses with the adventitia of the ICA to form a competent ring that separates the intradural ICA from the extradural ICA. The thin inner membranous layer of the dura loosely surrounds the ICA throughout the entire length of its clinoid segment. The most proximal aspect of this membrane defines the proximal dural ring. The proximal ring is incompetent and admits a variable number of veins from the cavernous plexus that accompany the ICA throughout its clinoid segment.

CONCLUSION

The narrow space between the inner dural layer and the clinoid ICA is continuous with the cavernous sinus via an incompetent proximal dural ring. This space between the clinoid ICA and the inner dural layer contains a variable number of veins that directly communicate with the cavernous plexus. Given the inconstancy of the venous plexus surrounding the clinoid ICA, we think that categorical labeling of the clinoid ICA as intracavernous or extracavernous cannot be justified.

Vascular complications of transsphenoidal surgery

Vascular complication of transsphenoidal surgery can lead to mortality and serious morbidity. In a series of 3,061 transsphenoidal operations for pituitary disease, 24 such complications were encountered, seven of which were fatal. The anatomic substrate for such complications is discussed, along with technical aspects of surgery and other methods for the avoidance of vascular complications.

Angiographic embolization for epistaxis: a review of 114 cases

Angiography with selective embolization has become an accepted method of treating posterior epistaxis that is not controlled with conservative measures. The authors reviewed 112 cases of patients who had received selective angiographic embolization for refractory epistaxis from January 1990 to December 1995. There were 114 embolizations over this 5-year period. The immediate success rate was 93%, with long-term success achieved in 88% of patients. The overall complication rate was 17%, with the long-term morbidity rate less than 1%. Selective angiographic embolization is a safe and effective method that should be considered in the treatment of refractory epistaxis.

Surgical landmarks of the infratemporal fossa

Surgical interventions on the infratemporal fossa require an accurate knowledge of the surgical anatomy. Thirty-four adult human skulls were examined and measurements made of the distance between the zygomatic arch and the root of the lateral pterygoid plate. The distance between the central part of the lateral and medial pterygoid plates was also measured. The first measurement represents the distance of the foramen ovale from the zygoma; the average being 38.2 mm. The average distance between the pterygoid plates is 9.6 mm. Addition of these two measurements represents the distance of the lateral wall of the nasopharynx from the zygoma and the average is 47.8 mm. Together with the knowledge of the arrangement of the muscle layers and the nerves and vessels in this region, this information has proved useful in the surgery of the area.

[Studies on the foramen vesalius in the Japanese juvenile and adult skulls]

Foramen Vesalius is known to be an inconstant foramen, which appears in the anteriomedial side of the foramen ovale. The foramen Vesalius is classified into the open type and the closed type. We studied the frequencies and the types of foramen Vesalius in Japanese by examining 20 juvenile skulls from 3 months to 8 years old and 400 adult skulls from 18 to 91 years old. Of the 20 juvenile skulls, 11 skulls (55.00%) had foramen Vesalius. Of the 400 adult skulls, 87 skulls (21.75%) had foramen Vesalius; 69 (21.50%) in 321 male and 18 (22.78%) in 79 female skulls. No remarkable differences were observed in the ratio between the male and the female, and between the left side and the right side. Among the 69 adult male skulls, the foramen Vesalius was bilateral in 52 skulls (75.36%) and unilateral in 17 (24.64%); among the 18 adult female skulls, it was bilateral in 13 (72.22%) and unilateral in 5 (27.78%). The ratio of the closed type was slightly higher than that of the open type in both sexes and in both sides; however, no remarkable differences were observed. The skulls with one foramen Vesalius were most frequent; those with two followed it and those with 3 foramen Vesalius were least frequent. No remarkable differences were observed in the number of foramen Vesalius between the sexes and the sides.

Arterial injuries in transsphenoidal surgery for pituitary adenoma; the role of angiography and endovascular treatment

PURPOSE

To define the role of angiography and embolization in the treatment of patients who have arterial injuries during transsphenoidal surgery.

METHODS

We retrospectively studied the arterial hemorrhagic complications, their management, and the clinical outcomes that occurred in 21 of the more than 1800 patients who had transsphenoidal surgery for pituitary adenomas.

RESULTS

Of the 21 patients who had complications, 17 had internal carotid injuries and four had injuries of the sphenopalatine artery. Angiography was performed in 18 patients. Bleeding occurred and was controlled during surgery in 16 cases. Delayed epistaxis occurred in 10 patients, including five whose surgery was uneventful. After internal carotid injury, the most frequent angiographic findings were carotid occlusion (eight patients), stenosis (five patients), and false aneurysms (three patients). Internal carotid balloon occlusion was performed in five patients. No rebleeding occurred in patients who had complete carotid occlusion either from surgical packing or balloon embolization. Two of the patients who had carotid stenosis after surgical packing had delayed epistaxis necessitating balloon occlusion. Injuries to the sphenopalatine artery were successfully treated by surgery (one patient) or by endovascular treatment (three patients) without complication. Three deaths and five permanent deficits were directly related to the arterial injury or its treatment.

CONCLUSION

Profuse bleeding during and after transsphenoidal surgery should be investigated by angiography. Lesions of the sphenopalatine arteries are effectively treated by embolization. Internal carotid injuries are best treated by carotid infusion to prevent life-threatening epistaxis.

Repair of nasal septal perforation

The management of nasal septal perforation remains unsatisfactory. Various operative techniques have been described, with modest success. A novel method for repair of septal perforations up to 2.6 cm in diameter was investigated. A double layer closure of nasal septal perforation was designed, one with the cartilage and the other by a flap based on the anterior septal branches of the sphenopalatine artery. Fourteen patients have been operated upon. The current analysis reveals a success rate of 13 patients (93%) who had complete closure and one patient (7%) with incomplete closure. The operative techniques and results are reported here.

The meningohypophyseal trunk and its blood supply to different intracranial structures. An anatomical study

50 meningohypophyseal trunks of the intracavernous internal carotid artery were studied in 25 human cadavers. Special attention was given to the main variations of branching patterns of this trunk. The dorsal meningeal arteries were found in all cases and three typical variations were observed in their origins and courses: a prominent medial branch (52%), a bifurcating type (38%) or a single lateral branch was present (10%). The tentorial artery of Bernasconi-Cassinari arised as a single branch in 64% of the cases, while in 36% two or more branches took a direct origin from the main trunk. The inferior hypophyseal artery was prominent in 82% of the cases. The inferolateral trunk had a common origin with the meningohypophyseal trunk in 8% of our dissections. A large number of anastomoses between these vessels was observed. As a number of tumorous and vascular pathologies, which can be treated with microsurgical techniques, take their origin from the cavernous sinus, the knowledge of the smaller vessels arising from the intracavernous internal carotid artery as well as their main variations is important.

Direct intraoperative sclerotherapy of an aneurysmal bone cyst of the sphenoid

A young boy presented with a symptomatic aneurysmal bone cyst of the left great wing of the sphenoid bone. Arterial embolization had failed to produce thrombosis, and the lesion could not be resected surgically. Direct intraoperative sclerotherapy resulted in immediate thrombosis of 80% of the volume of the vascular malformation with no progression of symptoms. Two years later, the symptoms had completely resolved, and CT scans showed total ossification of the lesion.

Sphenoidal artery, ramus orbitalis persistens and pterygospinosus muscle--a unique cooccurrence of first branchial arch anomalies in man

In a 76-year-old Caucasian male, the right middle meningeal was replaced by a branch of the ipsilateral ophthalmic artery (O), i.e. the sphenoidal artery (S); the right foramen spinosum was found to be absent. In the orbit, the right O bifurcated into a medial (merely orbital) and a lateral division, i.e. a meningolacrimal trunk. From that trunk, the S branched off and entered the middle cranial fossa at the superolateral angle of the superior orbital fissure. In addition, an anastomotic channel was formed by a remnant of the ramus orbitalis, connecting the right infraorbital with the deep orbital artery. The right accessory meningeal (AM) regularly arose from the maxillary artery and entered the cranial cavity through the foramen ovale, separated from the mandibular nerve by a pterygospinosus muscle. This muscle was merely present in the right infratemporal fossa. Interestingly, the left AM originated from the posterior deep temporal artery. No other anatomical variations were found in this individual. Since the coexistence of an S with variations of other structures derived from the first branchial arch has not been previously reported in man, the embryology and comparative anatomy of this irregular vessel are discussed.

Subperiosteal, subperiorbital dissection and division of the anterior and posterior ethmoid arteries for meningiomas of the cribriform plate and planum sphenoidale: technical note

Removal of meningiomas from the region of the cribriform plate and the planum sphenoidale may entail a bifrontal craniotomy and an interruption of the tumor's blood supply along the floor of the anterior cranial base. However, with this approach, the presence of bulky tumor above makes it difficult to control bleeding from multiple bony foramina in the anterior cranial base and to expose these foramina. The blood supply to the dura in this region, and, therefore, to these tumors, is predominantly from the anterior and posterior ethmoid arteries. Preoperative embolization of ethmoid arteries is not without a significant and prohibitive risk of blindness. A frontoethmoidal approach to the arteries on both sides requires two separate skin incisions. Therefore, a subperiosteal, subperiorbital dissection and division of these arteries via a bicoronal skin incision is a practical alternative.

Skull-base foramina of the middle cranial fossa: reassessment of normal variation with high-resolution CT

PURPOSE

To evaluate by means of high-resolution CT the anatomic variations of the middle cranial fossa foramen.

METHODS

We examined 123 CT studies of the temporal bone in patients with no evidence of disease that might alter foraminal anatomy. A checklist of known variants and suspected structures was used as each case was systematically examined for the presence or absence of these foramina; variations in size, shape, and location; and relationship of structures to each other. Inclusion criteria were established to eliminate error.

RESULTS

The foramen rotundum had a constant appearance. We identified the inferior rotundal canal in 16% of patients and the lateral rotundal canal in 8%. The foramen of Vesalius was present, at least unilaterally, in 80% of our cases. Asymmetry of the foramen of Vesalius did not indicate disease in our patient group. We did not find an inverse relationship between the size of the foramen of Vesalius and that of the ipsilateral foramen ovale. We found variations in the size and shape of the foramen ovale and its confluence with the foramen spinosum (n = 2) and the foramen of Vesalius (n = 8). We did not find an inverse relationship between the size of the foramen ovale and that of the foramen spinosum. The canaliculus innominatus for the lesser superficial petrosal nerve was identified in 16.3% of our patients. Variations of the foramen spinosum that we found include a medial bony defect (26.8%) and absence (3.2%).

CONCLUSION

Although it is unlikely that well-formed foramen will be misinterpreted as diseased, it is nonetheless important to recognize foraminal variants and associated neurovascular anatomy.

Meningiomas involving the anterior clinoid process

We report a series of 34 clinoidal meningiomas treated surgically and analyse the results according to cavernous sinus involvement. Fifteen tumours extended into the cavernous sinus. Only four of these could be resected completely, and global outcome was improved or stable in 10 cases. Overall, 20 tumours had a total resection and 14 had a partial resection. Complete removal of the sphenoid wing, including the anterior clinoid and part of the planum sphenoidale, allows early devascularization of the tumour and minimizes brain retraction when associated with resection of the zygomatic arch. The most frequent postoperative complication was transient CSF leak, occurring in three patients. Two patients died postoperatively, and three suffered permanent complications. There was no recurrence after total removal, but five patients showed signs of progressive tumour growth after partial removal, treated by radiotherapy in three and by surgery in two cases. Twenty patients showed preoperative visual impairment. Outcome of vision was improved or stable in 13 (68%) and worse in six cases (32%). We suggest that progressive visual impairment should lead to aggressive surgical treatment, especially when complete resection of cavernous sinus involvement can be performed.

Internal maxillary artery variability in the pterygopalatine fossa

The third segment or pterygopalatine branch of the internal maxillary artery has variable branching in the pterygopalatine fossa. This variability in branching can lead to failure in controlling persistent nasal epistaxis by transantral ligation. Although the surgical approach has been previously studied, a systematic classification of this branching has not been previously reported. Through the performance of serial cadaver dissections in the PPF, we have demonstrated the anatomic course and variations of this third segment and offer a relatively simple classification system.

The groove in the orbital face of the greater wing of the sphenoid. A new interpretation

A presumed arterial groove on the orbital face of the greater wing of the sphenoid in the human skull has been shown to be artefact produced by an abrupt thinning of bone. There is no evidence from this study to support the presence of a ramus orbitalis in man.

[Changes in the sphenoid bone in the upper third of the carotid groove]

The article discusses the changes of the bone plate of the sphenoid bone in the upper third of the carotid groove; the plate separates the siphon of the internal carotid artery from the cavity of the sphenoid sinus. Both carotid grooves were examined on blocks removed from the base of the skull of 65 cadavers and on 45 macerated skulls. Two types of bone changes were found in the upper third of the carotid groove, namely, osteoporosis and perforating defects. Osteoporosis was revealed in 50 grooves and defects only in the upper third in 45 grooves. Osteoporosis and defects were encountered about five times more frequently between the ages of 41 and 60 than till the age of 40 and 10 times more frequently after the age of 60. The same relations were found when osteoporosis was combined with a defect. These bone defects are an anatomical precondition for profuse nasal bleeding because the wall of the internal carotid artery ruptures during a craniocerebral trauma and blood flows freely from it into the sphenoid sinus and then into the nasopharynx.

Management of a ruptured pseudoaneurysm of the sphenopalatine artery following a Le Fort I osteotomy

A case of extreme, recurrent epistaxis secondary to a ruptured aneurysm of the sphenopalatine artery is reported and diagnosis of the condition by angiography and its treatment by Gianturco coil embolization is discussed.

Orbital infarction in sickle cell disease

Bone infarction is common in sickle cell disease; however, involvement of the orbit is not. Only four cases have been reported in the English literature. We describe a patient who presented with headache, proptosis and lid edema due to infarction of the sphenoid bone. The combination of radionuclide bone imaging and computed tomography (CT) of the orbit were useful in differentiating bone infarction from other etiologies of proptosis.

[The canalis basilaris medianus on the x-ray and computed tomogram (author's transl)]

The canalis basilaris medianus is a persistent venous canal in the Clivus, which was first described by Gruber. Depending on the type of the canal, course and projection the canal is mostly recognized on the x-ray as a longitudinal or diagonal translucent band, seldom as a round translucence; on the computed tomogram depending on the directional course in the layer as a round translucence of a longitudinal translucent band. It was detectable in 4,3% (14/332) of the examined x-rays (occipitomental projection, skull base) and in 6/154 (3,8%) of the computed tomograms of the skull base. By measuring computer-tomographically the increase of the CT-absorption values in the canal lumen after injection of a contrast medium, it was confirmed that there is a vessel in the canal. The differential diagnosis to canalis cranio-pharyngeus, foveola pharyngea and fracture is discussed.

The vidian artery: normal and pathologic anatomy

Arising as a branch of either the distal maxillary artery or the petrous portion of the internal carotid artery, the vidian artery (artery of the pterygoid canal) participates in two complex vascular networks through its anastomoses in the pterygopalatine fossa and oropharyngeal mucosa. The vidian artery may become a major source of blood supply to a variety of deep facial and paracavernous lesions. The embryology, anatomy, and pathology of this vessel are described and implications of its anastomotic patterns in therapeutic embolization procedures are discussed.

Vascular changes in the pterygopalatine fossa after craniofacial dysjunction surgery

A study was undertaken to determine vascular changes and the timing of these changes after craniofacial dysjunction surgery. Ten adult male Macaca cynomulgus monkeys were studied with techniques using angiograms and vascular vinyl cast preparations before and after unilateral Le Fort III osteotomy. After surgical disruption of the maxillary artery, the flow of blood was initially maintained by anastomotic branches of the ipsilateral internal carotid artery. Stepwise reconstruction of the disrupted maxillary artery took place via numerous collateral vessels that bridged the site of disruption; continuity of the artery was nearly normal by five weeks.

Surgical anatomy of the pterygopalatine fossa

The pterygopalatine fossa is the distribution centre for the main vessels and nerves of the middle third of the face. Its surgical anatomy is discussed, with particular emphasis on the relationship between the medical plate of the pterygoid process of the sphenoid bone and the vertical plate of the palatine bone; the position of the several foramina is reviewed also. It is stressed that the vascular contents of the pterygopalatine fossa lie in a coronal plane, anterior to the neural contents. Finally, a short review is given of the different surgical approaches to the pterygopalatine fossa. It is concluded that the transantral approach to the fossa, as originally described by Carnochan (1858), still seems to be the best way to gain access to this space.

The trans-sphenoidal vascular route in relation to the human pharyngeal hypophysis

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Vascularity of the environs of the human pharyngeal hypophysis as a possible indiction of the mechanism of its control

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