Characteristics of the interatrial communication in patients undergoing transcatheter device closure of atrial septal defects for cryptogenic stroke

Background: Prior studies suggest that patent foramen ovale (PFO) diameter >4 mm is associated with a high probability of cryptogenic ischemic stroke (CIS). Methods: We evaluated all patients diagnosed with CIS who underwent closure of intra-atrial communication (IAC) using the Amplatzer atrial septal defect (ASD) occluder in our institution between August 1997 and March 2004. For each IAC, echocardiographic diameters and balloon-stretched diameters were recorded. Stretchability index was calculated as the ratio of stretched diameter to unstretched diameter. Results: Fifty-six patients met the inclusion criteria for this study. There was an inverse logarithmic relationship between unstretched IAC diameter and stretchability index. For the 28 smaller defects, the median IAC diameter was 2 mm, and median stretchability index was 5.58 (range 2.6–15). For the 28 larger defects, median diameter was 6 mm, and median stretchability index was 2.38 (range 1.05–5). The difference in stretchability index between the two groups was significant ( P < 0.0001). Conclusion: Our data bring into question the concept that the diameter of the defect would singularly predict the probability of stroke.     

Foramen magnum meningioma presenting as amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a progressive, degenerative disease of the nervous system. It affects adults in all age groups and leads to death few years after the diagnosis. The etiology is unknown, and there no convincing medical or surgical therapy. Some diseases can mimic ALS. If diagnosed early these may be treatable, but if misdiagnosed as ALS and left untreated they may be fatal. We present a case of foramen magnum meningioma presenting clinically as ALS. After surgery, the symptoms disappeared and the neurological deficits improved.     

Zygomaticofacial,zygomaticoorbital and zygomaticotemporal foramina: anatomical study

The zygomatic nerve may be disrupted when elevating periorbita from the lateral wall during orbital surgery, and care should be taken to prevent injury to this nerve during lateral orbitotomy approaches to access intraorbital soft-tissue tumors. Furthermore, the precise introduction of anesthetics to the zygomaticoorbital (ZO), zygomaticofacial (ZF) and zygomaticotemporal (ZT) foramina could be important data for the plastic and reconstructive surgeon operating in the area. The aim of the present study was to investigate the morphologic and topographic anatomy, and variations of the ZO, ZF and ZT. The present study was performed using 200 dry human skulls. The ZF, ZO and ZT foramina varied from being absent to as many as four small openings. We classified each of these foramina as types I-V for single, double, triple, quadruple and absent foramina, respectively. The relative frequency was as follows: type I, ZO 50%, ZF 40%, ZT 30%; type II, ZO 20%, ZF 15%, ZT 15%; type III, ZO 10%, ZF 5%, ZT 5%; type IV, ZO 3%, ZF 1%, ZT-; and type V, ZO 17%, ZF 39%, ZT 50%. A detailed knowledge of the anatomic morphometry of this area is necessary for a surgeon when performing maxillofacial surgery and regional block anesthesia. Anatomic variations in this area may be present and a surgeon must take this into consideration so as to increase surgical success.     

Radiographic study of the mandibular retromolar canal: an anatomic structure with clinical importance

Introduction

The retromolar canal is an anatomic structure of the mandible with clinical importance. This canal branches off from the mandibular canal behind the third molar and travels to the retromolar foramen in the retromolar fossa. The retromolar canal might conduct accessory innervation to the mandibular molars or contain an aberrant buccal nerve.

Methods

Patients referred for panoramic radiography were consecutively enrolled, provided a limited cone-beam computed tomography (CBCT) scan had also been taken in the area of interest. Radiographs were retrospectively screened for the presence of a retromolar canal, and linear measurements (distance to second molar, height, width) were taken.

Results

One hundred twenty-one sides in 100 patients were evaluated (100 unilateral and 21 bilateral cases). A total of 31 retromolar canals were identified with CBCT (25.6%). Only 7 of these canals were also seen on the corresponding panoramic radiographs. The existence of a retromolar canal was not statistically related to gender or side. With regard to the linear measurements, the mean distance from the retromolar canal to the second molar was 15.16 mm (±2.39 mm), the mean height of the canal was 11.34 mm (±2.36 mm), and the mean width was 0.99 mm (±0.31 mm).

Conclusions

This radiographic study documents a frequency of 25% for the presence of a retromolar canal. The clinician is advised to preserve this anatomic variation when performing surgery in the retromolar area and to consider additional locoregional anesthesia in the case of failed mandibular block anesthesia.     

Characterisation of additional mental foramina through cone beam computed tomography

Variations in jaw bone neurovascularisation must be identified to decrease the potential risk for haemorrhages and neural disturbances during surgical procedures such as implant placement and orthognatic surgeries. The aim of this study is to characterise additional mental foramina (AMF) through cone beam computed tomography (CBCT) images, by describing their frequency, size, location and direction of their associated bony canals, as well as to assess their corresponding ipsilateral and contralateral mental foramina (MF). CBCT images from 285 patients were analysed. Prevalence of AMF was 9·4%. From 0 to 2 AMF were observed, with two bilateral cases. Two cases of unilateral absence of MF were registered. Patients presenting AMF did not differ significantly from those without AMF regarding gender, age or ethnicity. Diameters of AMF and their corresponding ipsilateral and contralateral MF were 1·9 mm (±0·7 mm), 3·8 mm (±0·6 mm) and 4·1 mm (±0·6 mm), respectively. Ratios between diameters of AMF and corresponding ipsilateral MF ranged between 0·24 and 0·99. Location of AMF was variable, with most cases located posteriorly, posterior-inferiorly, posterior-superiorly or anterior-superiorly to their respective MF. Significant anatomical variability regarding neurovascularisation was observed among patients and CBCT examinations presented as a valuable tool for individually assessing these anatomical features.     

Supratrochlear foramen of the humerus

The presence of the supratrochlear foramen was studied in 150 dry adult humeri, of unknown sex from the Department of Anatomy, St John's Medical College, Bangalore: The dimensions of the foramen were measured. In bones where the foramen was absent, opacity or translucency of the septum was observed. A supratrochlear foramen was found in 28% of the total humerii. It was almost equal in number on both the sides (right, 27.9%; left, 27.8%). Most of the foramina were oval in shape, their transverse and vertical diameters being, on average, 6.92 mm and 4.64 mm, respectively. A translucent septum was seen in 66% of the bones, in 51.51% of right and in 48.48% of the left. Only nine bones had opaque septae (6%). The study was done on bones belonging to South Indians and the findings were compared with the data available on other races. The paper discusses the evolutionary aspects of the foramen in addition to its surgical and orthopedic significance.     

Microsurgical considerations of the anterior spinal and the anterior-ventral spinal arteries

Summary Background. There are few data describing the microanatomy of the anterior-ventral spinal (AVSA) and anterior spinal arteries (ASA) and discussing their clinical and surgical implications. We describe the anatomical features of this arterial complex, and highlight their use when planning and performing surgical approaches to lesions involving the ventral aspect of the medulla and the foramen magnum. Method. The microsurgical anatomy and branching pattern of the AVSA and the ASA from fifty human cadaver brain stems is described using a surgical microscope. Results. We found one anterior-ventral spinal artery at each side in 30 of the brain stems (60%). The ASA was a direct branch emerging from the left vertebral artery (VA) in 15 (30%), from the right VA in 4 (8%), and from the basilar artery (BA) in one brain stem (2%). The previously described as “typical pattern” of the junction of the AVS arteries from both sides, was observed only in 9 brain stems (18%). The anterior communicating spinal artery (ACoSA) was observed in 15 brain stems (30%). Also multiple ACoS arteries were described in one brain stem. Both, the AVSA and the ASA were observed to send long circumferential branches that supplied irrigation to the olive in 42 (84%) brain stems. Conclusions. This anatomical study gives important information for a better understanding of the clinical picture of ischemic lesions of the brain stem, such as the medial medullary syndrome, and highlights the remarkable role of the AVSA and ASA as anatomical landmarks during the surgical approaches to lesions involving the ventral aspect of the medulla and the foramen magnum.     

Morphological characteristics of the infraorbital foramen and infraorbital canal using three-dimensional models

Infraorbital nerve blocking through the infraorbital foramen and infraorbital canal is used to anesthetize the lower eyelid, upper lip, lateral nose, upper teeth and related gingivae. For this, it is important to know the position of the infraorbital foramen, structures around the foramen, and the direction of the injecting needle related to the angle of the infraorbital canal. Many reports have described the anatomical location of the infraorbital foramen; however, not many have described the angle of the infraorbital canal and those structures around the infraorbital foramen that help the physician visualize the correct direction of the needle. Dried skulls of 42 Korean subjects (27 male and 15 female) were studied to analyze structures around the infraorbital foramen. The morphology of the infraorbital canal was also investigated using three-dimensional models. Structures around the infraorbital foramen were classified into four types according to the existence of a distinct tuberosity above the infraorbital foramen, and the degree of prominence of the canine fossa. Types I and II have a tuberosity above the infraorbital foramen, whereas types III and IV have no distinct tuberosity. Types I and III have a prominent canine fossa, whereas this is less prominent in types II and IV. We analyzed the skulls based on the angle of the infraorbital canal to the median plane. We compared the left and right sides and analyzed differences between the sexes, the three canal shapes, and the four structure types around the infraorbital foramen. Type IV was the most common in this series (38%). The infraorbital canal could be classified into three morphologies: ‘tube-like’ (69%), ‘funnel’ (25%) and ‘pinched’ (6%). The mean angle of the infraorbital canal relative to the median plane was 12°, and the angle relative to the Frankfurt plane was 44°. The mean angle between the infraorbital canal and the Frankfurt plane was 4° larger in males than in females in this series of Korean subjects. The operator of the infraorbital nerve block should pay attention towards directing the needle upward at an angle of about 44° for avoiding nerve damage and consider the different angles of the canal according to the individual’s sex.