Ultrasonographic assessment of the maxillary artery and middle meningeal artery in the infratemporal fossa

Role of magnetic resonance imaging in temporomandibular joint ankylosis - An evaluative study

Introduction

Temporomandibular joint (TMJ) ankylosis is a pathologic condition where the mandible is fused to the fossa by bony or fibrotic tissues. Haemorrhage is one of the major complications during TMJ surgery especially in ankyloses due to altered anatomy. The aim of the study was to analyse the proximity of the vasculature to the TMJ region in TMJ ankylosis patients using magnetic resonance imaging (MRI)

Materials and Methods:

Noncontrast-enhanced MRI images of seven patients were assessed. The distance between maxillary artery and neck of condyle/ankylotic mass was measured using coronal sections and distance between the internal carotid artery (ICA), internal jugular vein (IJV) and medial edge of condyle/bony mass were measured using axial sections.

Results:

The mean distance of internal maxillary artery (IMA) to medial edge of ankylotic mass was 1 ± 0.57 mm and 2 ± 1.2 mm-left and right condylar regions respectively (range: 0–4 mm).The mean distance from lateral aspect of ankylotic mass to IMA was 8.2 ± 1.4 mm and 8.7 ± 2.8 mm–right and left condylar regions respectively (range: 3–11 mm).The mean distance from medial edge of condyle to ICA was 18.8 ± 1.3 mm and 18.2 ± 1.1 mm-right and left condylar regions respectively (range: 17 mm–20 mm).The mean distance from the medial edge of condyle to IJV was 16.4 ± 1.1 mm and 14.5 ± 2.9 mm-right and left condylar regions (range: 11 mm–19 mm).

Discussion:

These measurements were used as a guide to plan the steps during surgery in order to minimise the intraoperative haemorrhagic complications. Hence, MRI may be considered as a valuable tool in assessing the juxtaposition of vascular bed to TMJ region, though contrast MRI and a larger sample is needed to standardise.

Maxillary artery involvement in giant cell arteritis demonstrated by ultrasonography

We describe two cases of giant cell arteritis where involvement of the superficial temporal artery and maxillary artery were demonstrated using colour doppler ultrasonography. Maxillary artery involvement is responsible for the symptoms of jaw claudication and toothache, and even headaches might be due to the involvement of the middle meningeal artery which is a branch of the maxillary artery. The maxillary artery has been difficult to visualise until now. There are international consensus definitions of ultrasonographic abnormalities seen in the superficial temporal artery affected by giant cell arteritis. We have used those definitions to demonstrate hypoechoic changes in the maxillary artery affected by giant cell arteritis. The maxillary artery can be visualised in the infratemporal fossa from an echo window between the condylar and coronoid processes of the mandible. This is the first proof of concept evidence that maxillary arteries can be visualised using bedside ultrasonography in giant cell arteritis.

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.

Vascular actions of peripheral CGRP in migraine-like photophobia in mice

BACKGROUND

Calcitonin gene-related peptide is recognized as a key player in migraine, yet the mechanisms and sites of calcitonin gene-related peptide action remain unknown. The efficacy of calcitonin gene-related peptide-blocking antibodies as preventative migraine drugs supports a peripheral site of action, such as the trigeminovasculature. Given the apparent disconnect between the importance of vasodilatory peptides in migraine and the prevailing opinion that vasodilation is an epiphenomenon, the goal of this study was to test whether vasodilation plays a role in calcitonin gene-related peptide-induced light aversive behavior in mice.

METHODS

Systemic mean arterial pressure and light aversive behavior were measured after intraperitoneal administration of calcitonin gene-related peptide and vasoactive intestinal peptide in wild-type CD1 mice. The functional significance of vasodilation was tested by co-administration of a vasoconstrictor (phenylephrine, endothelin-1, or caffeine) with calcitonin gene-related peptide to normalize blood pressure during the light aversion assay.

RESULTS

Both calcitonin gene-related peptide and vasoactive intestinal peptide induced light aversion that was associated with their effect on mean arterial pressure. Notably, vasoactive intestinal peptide caused relatively transient vasodilation and light aversion. Calcitonin gene-related peptide-induced light aversion was still observed even with normalized blood pressure. However, two of the agents, endothelin-1 and caffeine, did reduce the magnitude of light aversion.

CONCLUSION

We propose that perivascular calcitonin gene-related peptide causes light-aversive behavior in mice by both vasomotor and non-vasomotor mechanisms.