The anatomic relationship around the horizontal segment of petrous internal carotid artery: a study based on reconstructed computed tomography angiography

Purpose

The anatomic relationship around the horizontal segment of petrous internal carotid artery (ICA) is complicated. Relative researches on human patients using radiographic technique are scarce. It is essential to get adequate anatomic knowledge about this region for performing some bypass procedures.

Methods

Using the independent software Mimics, we prospectively studied the 0.45-mm-thick computed tomography angiography (CTA) images of 29 patients (58 sides). All patients’ middle cranial fossa and related critical anatomic structures were reconstructed in 3D. Some measurements were established on the multiplanar reconstructed images, including the distance from foramen ovale and foramen spinosum to the petrous ICA; the distance from the lumen of cochlea to the edge of trigeminal impression and petrous ICA; and the length of the horizontal segment of petrous ICA.

Results

The horizontal segment of petrous ICA was surrounded by the trigeminal impression, the cochlea and the auditory tube spatially. On the multiplanar reconstructed CTA images, the average distances from foramen ovale and foramen spinosum to the petrous ICA were 4.1?mm and 5.8?mm, respectively; the average distance from the lumen of cochlea to the edge of trigeminal impression and petrous ICA were 8.2?mm and 2.0?mm, respectively; and the mean length of the horizontal segment of petrous ICA was 15.8?mm.

Conclusions

Our results indicate adequate and reliable anatomic information can be obtained using reconstructed CTA on an individualized basis.     

Original landmarks for intraoperative localization of the foramen ovale: a radio-anatomical study

Purpose

Radiofrequency lesioning is one of the frequently used modalities for the treatment of trigeminal neuralgia. Easily identifiable radiological landmarks are necessary for correct intra-operative localization of foramen ovale.

Methods

One hundred and seventy sides of dry skulls were studied for the following measurements. D-1: the transverse distance between the apex of the petrous temporal and the centre of the foramen ovale. D-2: the transverse distance from the midline to the centre of the foramen ovale. The distances between the centre of the foramen ovale and, D-3: the anterior margin of mandibular fossa, D-4: centre of the mandibular fossa and D-5: point at the junction of posterior margin and floor of the sella. D-6: the vertical distance between the centre of the foramen ovale and point at the junction of posterior margin and floor of the sella.

Results

The mean values measured were D-1: 13.9?mm, D-2: 24.5?mm, D-3: 3.1?mm, D-4: 11.4?mm, D-5: 0.75 and D-6: 12.42?mm. In majority of cases the centre of foramen was around 25?mm from midline. Additionally the centre of the foramen was at the level of the junction of the posterior wall and floor of the sella or within 2?mm of this point in the antero-posterior direction. In most (81%) cases the vertical displacement of the foramen was 1–1.5?cm inferior to this point.

Conclusion

During intra-operative imaging, the midline of the skull and the junction of the posterior wall and floor of the sella can be used as reliable landmarks for the identification of foramen ovale.     

Morphology and compartmentation of the jugular foramen in adult Indian skulls

Purpose  

Knowledge of the complex anatomy of the jugular foramen is vital for a favorable surgical outcome in technically challenging operations of this region. Various reports about the compartmentation of this foramen and the contents passing through them have come up with conflicting observations.     

An anatomical study of the pterygospinous bar and foramen of Civinini

Purpose

The pterygospinous ligament extends from the posterior free margin of the lateral pterygoid plate till the spine of the sphenoid. The ligament may ossify partly or completely leading to the formation of the pterygospinous bar. A complete ossification of the ligament results in the formation of the foramen of Civinini. Presence of the complete or incomplete pterygospinous bar may lead to a difficulty in passing the needle during anaesthesia for the trigeminal neuralgia or the bar may also compress the mandibular nerve and its branches to cause lingual numbness, pain and speech impairment.

Method

Presence of the complete or incomplete pterygospinous bar and the foramen of Civinini were studied in 55 dried adult skulls and 20 sphenoid bones.

Results

Partial or complete ossification of the pterygospinous ligament was seen in 17.33 % skulls. One skull showed the presence of bilateral complete pterygospinous bar while another skull had the unilateral complete pterygospinous bar on right side. Two skulls and one sphenoid had bilateral incomplete pterygospinous bar while seven skulls and one sphenoid bone had unilateral incomplete pterygospinous bar. In three cases, the bar was passing just below the foramen ovale.

Conclusion

The pterygospinous bar when present medial to the foramen ovale may not have much clinical significance but when the bar is present just below the foramen ovale, it may cause a compression of the mandibular nerve and its branches and may also obstruct the passage for the transoval approach to the neighbouring regions.

     

Enhanced topical delivery and ex vivo anti-inflammatory activity from a betamethasone dipropionate formulation containing fish oil

Objective and design  

To probe ex vivo the influence of fish oil (FO) on the topical delivery and anti-inflammatory properties of betamethasone dipropionate (BD).     

Brainstem infarction in a patient with internal carotid dissection and persistent trigeminal artery: a case report

Background  

The primitive trigeminal artery (PTA) is the most commonly described fetal anastomosis between the carotid and vertebrobasilar circulations.     

A simple method to locate mandibular foramen: preliminary radiological study

Introduction  

The position of mandibular foramen is variable at the medial aspect of mandibular ramus. Nevertheless its location is useful for the oral and maxillofacial surgeon in orthognatic surgery, especially in vertical ramus osteotomy (VRO) procedure. The aim of our study is to analyse the position of mandibular foramen in order to provide simple and reliable surgical landmarks.     

Bony landmarks in the sacral region: the posterior superior iliac spine and the second dorsal sacral foramina: a potential guide for sonography

Purpose  

Identification of the second dorsal sacral foramen (S2F) by sonographic imaging is a possible first step in localising the branches of the dorsal sacral rami. The aim of this investigation is to develop an imaging approach to assist the rapid identification of S2F using a well-known regional landmark, the posterior superior iliac spine (PSIS).     

Type 2 proatlantal intersegmental artery associated with persistent trigeminal artery diagnosed by MR angiography

Purpose

The type 2 proatlantal intersegmental artery (PIA) is a rare anastomosis between the external carotid artery (ECA) and vertebral artery (VA) that passes through the foramen magnum. The persistent trigeminal artery (TA) is the most common anastomosis between the internal carotid artery (ICA) and basilar artery. The purpose of this paper is to present the first case of a type 2 PIA associated with an ipsilateral persistent TA diagnosed using magnetic resonance (MR) angiography, and we briefly discuss the embryology of this rare anomaly.

Methods

An 83-year-old man with cerebral infarctions underwent cerebral MR imaging, and head and neck MR angiography using a 1.5?T imager. MR angiography was obtained using the standard non-contrast three-dimensional time-of-flight technique.

Results

MR angiography showed aplasia of the proximal left VA and a large anastomotic artery between the left ECA and distal left VA that passed through the foramen magnum, indicative of a type 2 PIA. This patient also had an anastomosis between the precavernous segment of the left ICA and midbasilar artery via a lateral course, indicative of a lateral-type persistent TA.

Conclusion

We present the first case of type 2 PIA associated with ipsilateral lateral-type persistent TA diagnosed by MR angiography. MR angiography should be performed including the carotid bifurcation to find more frequently extracranial arterial variations, including type 2 PIAs.     

Lack of association between right-to-left shunt and cerebral ischemia after adjustment for gender and age

Introduction  

A number of studies has addressed the possible association between patent foramen ovale (PFO) and stroke. However, the role of PFO in the pathogenesis of cerebral ischemia has remained controversial and most studies did not analyze patient subgroups stratified for gender, age and origin of stroke.     

Custom-molded foot-orthosis intervention and multisegment medial foot kinematics during walking

Context:

Foot-orthosis (FO) intervention to prevent and treat numerous lower extremity injuries is widely accepted clinically. However, the results of quantitative gait analyses have been equivocal. The foot models used, participants receiving intervention, and orthoses used might contribute to the variability.

Objective:

To investigate the effect of a custom-molded FO intervention on multisegment medial foot kinematics during walking in participants with low-mobile foot posture.

Design:

Crossover study.

Setting:

University biomechanics and ergonomics laboratory.

Patients or Other Participants:

Sixteen participants with low-mobile foot posture (7 men, 9 women) were assigned randomly to 1 of 2 FO groups.

Interventions :

After a 2-week period to break in the FOs, individuals participated in a gait analysis that consisted of 5 successful walking trials (1.3 to 1.4 m/s) during no-FO and FO conditions.

Main Outcome Measure(s):

Three-dimensional displacements during 4 subphases of stance (loading response, mid-stance, terminal stance, preswing) were computed for each multisegment foot model articulation.

Results:

Repeated-measures analyses of variance (ANOVAs) revealed that rearfoot complex dorsiflexion displacement during midstance was greater in the FO than the no-FO condition (F_1,14 = 5.24, P = .04, partial η² = 0.27). Terminal stance repeated-measures ANOVA results revealed insert-by-insert condition interactions for the first metatarsophalangeal joint complex (F_1,14 = 7.87, P = .01, partial η² = 0.36). However, additional follow-up analysis did not reveal differences between the no-FO and FO conditions for the balanced traditional orthosis (F_1,14 = 4.32, P = .08, partial η² = 0.38) or full-contact orthosis (F_1,14 = 4.10, P = .08, partial η² = 0.37).

Conclusions:

Greater rearfoot complex dorsiflexion during midstance associated with FO intervention may represent improved foot kinematics in people with low-mobile foot postures. Furthermore, FO intervention might partially correct dys-functional kinematic patterns associated with low-mobile foot postures.     

Persistent trigeminal artery and its variants on MR angiography

Introduction  

A persistent trigeminal artery (PTA) is the most common carotid-vertebrobasilar anastomosis. A cerebellar artery that arises from the precavernous segment of the internal carotid artery (ICA) without connecting to the basilar artery is regarded as a PTA variant. Our study aimed to determine the incidence of PTA and its variants and classify them based on magnetic resonance (MR) angiography.     

Double mandibular foramen leading to the accessory canal on the mandibular ramus

Purpose

The knowledge of the variation in the mandibular foramen and canal is clinically significant in surgical procedures of the mandible. This study aims to evaluate the anatomical characteristics of double mandibular foramen leading to the accessory canal on the mandibular ramus using cone beam CT.

Methods

The sagittal, cross-sectional, and three-dimensional images of cone beam CT data from 446 patients were evaluated in the presence of double mandibular foramen and the accessory canal passing through the foramen. The accessory canals were classified into two types according to the configuration (forward and retromolar type), and the location of double mandibular foramen was recorded.

Results

The eight double mandibular foramina leading to the accessory canals were observed in six patients out of 446 patients (1.35 % of population). Regarding the configuration of the accessory canal, there were two forward types and six retromolar types. All double mandibular foramina were located above the mandibular foramina on the medial aspect of the mandibular ramus.

Conclusion

Three-dimensional images of cone beam CT data are useful in confirming the presence of double mandibular foramen leading to the accessory canal. The variation may cause failure in the routine mandibular nerve block anesthesia and it is often vulnerable during surgical procedures involving the mandibular ramus. Also, double mandibular foramen is considered as an easy route for tumor cell to spread following the radiotherapy. Therefore, the variation should be carefully investigated using reconstructed cone beam CT images in planning of dental surgery or radiotherapy in the mandible.     

Ultrasound imaging of the infraorbital foramen and simulation of the ultrasound-guided infraorbital nerve block using a skull model

Purpose

Infraorbital nerve block is used for intraoperative and postoperative analgesia in nasal and oral surgery procedures, as well as in the chronic pain settings. Ultrasound guidance has not been described in the literature. The aim of the study was to assess the quality of ultrasound imaging of the infraorbital foramen and develop an “in-plane” technique of the block using a skull model.

Methods

The infraorbital foramina were assessed on five skull models immersed in the water bath. Ultrasound-guided simulation of an in-plane infraorbital nerve block was then performed. Slightly curved needle was placed close to the foramina and its visibility was recorded. Success rate and time to locate infraorbital foramina, success rate and time to insert the needle close to the foramina under ultrasound and correlation between the ultrasound and caliper measurements were evaluated and recorded. Data for the left and right foramen were compared.

Results

The infraorbital foramina were successfully located using ultrasound in all 20 cases. Simulation of infraorbital nerve block was also successful in all measurements. The time difference between locating or simulating blockade of the left and right infraorbital foramina was not statistically significant. Correlation between ultrasound measurement and direct measurement using a caliper was satisfactory for the distances between the inferior orbital rim and the inferior margin of the infraorbital foramen but poor for the distances between the lower rim of the orbit and the superior margin of the foramen.

Conclusions

This experimental study suggests that the infraorbital foramen is easily located using ultrasound and an “in-plane” ultrasound-guided technique for infraorbital nerve blockade is feasible on the model.     

Morphine Increases Acetylcholine Release in the Trigeminal Nuclear Complex

Study Objectives:

The trigeminal nuclear complex (V) contains cholinergic neurons and includes the principal sensory trigeminal nucleus (PSTN) which receives sensory input from the face and jaw, and the trigeminal motor nucleus (MoV) which innervates the muscles of mastication. Pain associated with pathologies of V is often managed with opioids but no studies have characterized the effect of opioids on acetylcholine (ACh) release in PSTN and MoV. Opioids can increase or decrease ACh release in brainstem nuclei. Therefore, the present experiments tested the 2-tailed hypothesis that microdialysis delivery of opioids to the PSTN and MoV significantly alters ACh release.

Design:

Using a within-subjects design and isoflurane-anesthetized Wistar rats (n = 53), ACh release in PSTN during microdialysis with Ringer''s solution (control) was compared to ACh release during dialysis delivery of the sodium channel blocker tetrodotoxin, muscarinic agonist bethanechol, opioid agonist morphine, mu opioid agonist DAMGO, antagonists for mu (naloxone) and kappa (nor-binaltorphimine; nor-BNI) opioid receptors, and GABA_A antagonist bicuculline.

Measurements and Results:

Tetrodotoxin decreased ACh, confirming action potential-dependent ACh release. Bethanechol and morphine caused a concentration-dependent increase in PSTN ACh release. The morphine-induced increase in ACh release was blocked by nor-BNI but not by naloxone. Bicuculline delivered to the PSTN also increased ACh release. ACh release in the MoV was increased by morphine, and this increase was not blocked by naloxone or nor-BNI.

Conclusions:

These data comprise the first direct measures of ACh release in PSTN and MoV and suggest synaptic disinhibition as one possible mechanism by which morphine increases ACh release in the trigeminal nuclei.

Citation:

Zhu Z; Bowman HR; Baghdoyan HA; Lydic R. Morphine increases acetylcholine release in the trigeminal nuclear complex. SLEEP 2008;31(12):1629–1637.     

A retrospective comparison of the location and diameter of the inferior alveolar canal at the mental foramen and length of the anterior loop between American and Taiwanese cohorts using CBCT

Purpose

The aim was to retrospectively compare the measurements of the location and size of the inferior alveolar canal at the mental foramen and the length of the anterior loop between two cohorts of Americans and Taiwanese using cone-beam computed tomography (CBCT).

Methods

CBCT was performed with an I-CAT^® Cone-Beam 3D Dental Imaging System and reconstructed into multiple-plane views to measure two populations.

Results

There was no statistically significant difference (P = 0.2681) in the distance from the mental foramen to the inferior border of the mandible (mandibular border height) between Americans (9.84 ± 2.01 mm) and Taiwanese (10.13 ± 1.66 mm). No significant difference was found (p = 0.1161) in the inferior alveolar canal diameter between these two cohorts (2.26 ± 0.67 and 2.13 ± 0.47 mm, respectively). However, the anterior loop length of Taiwanese (7.61 ± 1.81 mm) was significantly longer than that of Americans (6.22 ± 1.68 mm) (P < 0.0001).

Conclusion

Our study indicated that (1) the location of mental foramen of Americans was closer to the inferior border of the mandible than Taiwanese; (2) the diameter of the inferior alveolar canal of Americans was larger than Taiwanese; (3) the anterior loop of Taiwanese was longer than Americans. These differences may be, at least partly, due to the racial influence and this information may possess potential valuable clinical relevance.     

Morphology of the human xiphoid process: dissection and radiography of cadavers and MDCT of patients

Purpose

The purpose of this study was to evaluate the morphology of xiphoid process by dissection and using radiography of cadavers and multidetector computed tomography (MDCT) in patients.

Methods

The xiphoid processes of 41 cadavers were dissected and taken by radiography. Other 902 patients examined by MDCT were revealed by image post-processing used with multiple planar reconstruction, maximum intensity projection and volume rendering.

Results

Xiphoid processes displayed pointed shape in 422 cases (44.75 %), oval shape in 387 cases (41.04 %), and forked shape in 134 cases (14.21 %). The sagittal shape of the xiphoid process was observed as ventrally deviated in 217 cases (23.01 %), dorsally deviated in 191 cases (20.25 %), S-shaped (ahead ventral, then dorsal) in 21 cases (2.23 %), and resembling a hook in 14 of ventral deviated patients and in 19 of those dorsal deviated patients. The foramen of xiphoid processes was found in 544 cases (57.69 %). The pattern L (a large foramen with a diameter of more than 5 mm) appeared in 302 cases (55.51 %), pattern S (a small foramen with a diameter of no more than 5 mm) in 155 cases (28.49 %), pattern LS (a mixture of a large and a small foramina) in 37 cases (6.80 %), and pattern SS (two or more small foramina) in 50 cases (9.19 %).

Conclusion

Human xiphoid process appeared in morphological diversity. The anatomic structure and ossification degree of xiphoid process was well evaluated by MDCT. Our data may be used for diagnosis and surgical treatment of xiphoid process-related diseases.     

The anatomical and clinical details of the pterygoid canal: a three-dimensional reconstructive virtual anatomic evaluation based on CT

Purpose

To delineate the pterygoid canal (PC) configuration and its position in relation to surrounding important anatomical landmarks using three-dimensional reconstructive technology based on CT for the Chinese.

Methods

The computerized tomography arteriography (CTA) data of 137 patients were retrospectively evaluated using neuroimaging three-dimensional reconstructive software. The morphological parameters of the PC as well as the spatial relationship and distance between the PC relative to internal carotid artery (ICA) and the foramen rotundum were evaluated.

Results

83.9 % of the PC can be identified by our neuroimaging three-dimensional reconstructive software. The mean distance from the PC to the ICA was 2.6 ± 1.2 mm. The mean distance between medial aspects of bilateral ICA was 19.6 ± 2.7 mm. The distal vertical and horizontal distances between the PC and foramen rotundum were 5.2 ± 3.2 and 6.1 ± 2.8 mm, respectively. All the proximal end of the PC were inferior-lateral to the ICA. The PC mainly (92.9 %) ran posteriorly with a medial to lateral direction. The distance from the PC to ICA was positively correlated with the distance between bilateral ICA and the distal diameter of the PC. The vertical distance between the PC and foramen rotundum was positively correlated with the length of the PC and the horizontal distance between the PC and foramen rotundum.

Conclusions

Understanding the configuration and spatial relationship of the PC may be helpful to improve the accuracy and safety of operation during the expanded transnasal endoscopic approaches to skull base. The three-dimensional reconstructive virtual anatomic technology may be a useful tool to delineate the PC configuration and its position to surrounding important anatomical landmarks.     

Calvarial diploic venous channels: an anatomic study using high-resolution magnetic resonance imaging

Background

The calvarial diploic venous channels (CDVCs) are well-known intraosseous structures, but their distribution and anatomofunctional implications are not fully understood.

Objective

To investigate the architecture of CDVCs using high-resolution magnetic resonance (MR) imaging.

Method

This prospective study enrolled 43 male and 37 female outpatients who underwent a 3.0-T MR imaging equipped by a 32-channel head coil. T1-weighted imaging covering the whole cranial vault was performed after gadolinium injection. In addition, one-piece orbitozygomatic craniotomy was performed in three cadaveric heads to observe the interruption of the CDVCs.

Results

The CDVCs showed irregular contours and peculiar branching patterns with four common major pathways: the pteriofrontparietal (PFP), frontoorbital (FO), occipitoparietal (OP), and occipitocervical (OC) routes. The proximal PFP coursed as a single trunk and divided into several branches at the level of the frontal eminence. The orbital part of the FO continued to the subcutaneous vein via the supraorbital rim. The PFP and the pterional part of the FO fused proximally with the sphenoparietal sinus and descended as the middle meningeal vein. The OP coursed in the superoinferior direction and connected the junction part of the transverse-sigmoid sinus to the parietal superior sagittal sinus. The OC occurred as a single trunk in the median occipital bone, drained extracranially, and joined the suboccipital venous channels.

Conclusions

The CDVCs seem to be a relatively consistent network functioning not only as conduits connecting the intracranial dural sinuses but also as pathways to the extracranial venous systems. High-resolution MR imaging is useful for investigating the CDVCs.