The occipital-vertebral anastomosis revisited

BACKGROUND

The goal of the study was to provide relevant data about the location and prevalence of the occipital artery-vertebral artery (OA-VA) anastomosis in patients without visible occlusive disease, as well as to thoroughly discuss the clinical significance of these anastomotic channels. Furthermore, the morphometric properties of the OA and its branches were also analysed.

MATERIALS AND METHODS

A retrospective study was carried out to indicate anatomical variations, their prevalence, and morphometrical data on the OA and its branches. The study was performed on 55 randomly selected computed tomography angiographies (CTA) of the head and neck region. Each CTA result was analysed bilaterally. Thus, 110 results were originally assessed.

RESULTS

The OA median maximal diameter was demonstrated at 4.85 mm (lower quartile [LQ]: 4.11; upper quartile [UQ]: 5.53) and the median maximal diameter of VA at 3.60 mm (LQ: 2.79; UQ: 4.38). The distances between OA and its branches were also measured giving a median result of 21.73, 30.29, 60.84, 34.88, 18.02, 55.16 mm for the lower and upper sternocleidomastoid branch, meningeal branch, mastoid branch, and descending branch, respectively. The median distance between OA and its first anastomosis was set to be 51.15 mm (LQ: 37.20; UQ: 60.10). Moreover, a set of additional measurements was carried out in order to create a three-dimensional anatomical heat-map of the occurrence of the OA-VA anastomosis.

CONCLUSIONS

Knowledge about the anatomy of the OA-VA anastomosis might be of immense importance to avoid potentially fatal complications during embolisation of the OA and its branches.

Agenesis of the sphenoid sinus and a single sphenoid sinus: a computed tomography anatomical evaluation

BACKGROUND

Sphenoid sinuses are pneumatic spaces within the body of the sphenoid bone. Their development begins in the prenatal life and continues until the adulthood. Agenesis of the sphenoid sinuses is a situation in which they are undeveloped. On the other hand, asingle sphenoid sinus lacks the presence of the main septum, leading to the formation of a single antrum. Contemporary use of transnasal transsphenoidal approaches for the pituitary surgery, as well as functional endoscopic sinus surgery urges medical professionals to be well acquainted with the aforementioned variant.

MATERIALS AND METHODS

Paranasal sinuses of 300 patients (150 females, 150 males) were evaluated using computed tomography, without the use of contrast medium. Inclusion criteria involved absence of any identifiable pathology within the sphenoid sinuses and age over 18 years. Subgroup analysis involved probing for potential sources of heterogeneity, namely gender.

RESULTS

In the whole research material of 300 patients, agenesis of the sphenoid sinuses was noted in 1% of the patients. No statistically significant differences were noted between the absence of the sphenoid sinuses and gender (p = 0.999). A single sphenoid sinus was found in 0.33% of the patients. There were no statistically significant differences found between the presence of fully developed sphenoid sinuses and gender (p = 0.498).

CONCLUSIONS

Both agenesis of the sphenoid sinuses, as well as a single sphenoid sinus are rare anatomical variants. Adequate planning for transsphenoidal surgeries with preoperative medical imaging is of essence in order to perform a safe and quality procedure.

A computed tomography comprehensive evaluation of the ostium of the sphenoid sinus and its clinical significance

BACKGROUND

The purpose of this research was to evaluate the size of the sphenoid sinuses' ostia, the distance between them and the distance between the medial margin of the ostia and the median line in the Polish adult population.

MATERIALS AND METHODS

The analysis was undertaken as a retrospective study of 296 computed tomography (CT) scans of patients (147 females, 149 males) with no comorbidities in their sphenoid sinuses. The paranasal sinuses were investigated by using Spiral CT Scanner (Siemens Somatom Sensation 16), in the option Siemens CARE Dose 4D, without administering any contrast medium. Having obtained transverse planes, multiplans reconstruction tool was used in order to glean sagittal and frontal planes.

RESULTS

The average size of both sphenoid sinuses ostia was 0.31 cm for both genders (for females ranging from 0.1 to 0.5 cm and from 0.1 to 0.6 cm for males). The mean distance between both sphenoid sinuses ostia was 0.6 cm for both genders (the range for females was 0.1-1.4 cm, whereas 0.1-1.8 cm for males). The average distance between the medial margin of the ostium and the median line was 0.32 cm for both genders (0.31 cm for females in the range of 0-0.9 cm and 0.32 cm for males in the range of 0-1 cm).

CONCLUSIONS

Intraoperative identification of the sphenoid sinus ostia might prove difficult and their inadequate excision could lead to potential iatrogenic complications, hence detailed anatomical descriptions are still warranted in specific populations in order to perform safe and effective procedures.

The biology behind the human intervertebral disc and its endplates

The intervertebral discs (IVDs) are roughly cylindrical, fibrocartilaginous, articulating structures connecting the vertebral bodies, and allowing movement in the otherwise rigid anterior portion of the vertebral column. They also transfer loads and dissipate energy. Macroscopically the intervertebral disc can be divided into an outer annulus fibrosus surrounding a centrally located nucleus pulposus. The endplates surround the IVD from both the cranial and caudal ends, and separate them from the vertebral bodies and prevent the highly hydrated nucleus pulposus from bulging into the adjacent vertebrae. The IVD develop from the mesodermal notochord and receive nutrients mostly through the cartilaginous endplates. Physiologically they are innervated only in the outer annulus fibrosus by sensory and sympathetic perivascular nerve fibres, branches from the sinuvertebral nerve, the ventral rami of spinal nerves or from the grey rami communicantes. The IVD undergo changes with ageing and degeneration, the latter having two types i.e. "endplate-driven" involving endplate defects and inward collapse of the annulus fibrosus and "annulus-driven" involving a radial fissure and/or an IVD prolapse. This review summarises and updates the current state of knowledge on the embryology, structure, and biomechanics of the IVD and its endplates. To further translate this into a more clinical context this review also demonstrates the impact of ageing and degeneration on the above properties of both the IVD and its endplates.

Anatomy and clinical significance of the maxillary nerve: a literature review

BACKGROUND

The aim of this paper was to summarise the anatomical knowledge on the subject of the maxillary nerve and its branches, and to show the clinical usefulness of such information in producing anaesthesia in the region of the maxilla.

MATERIALS AND METHODS

A literature search was performed in Pubmed, Scopus, Web of Science and Google Scholar databases, including studies published up to June 2014, with no lower data limit.

RESULTS

The maxillary nerve (V2) is the middle sized branch of the trigeminal nerve - the largest of the cranial nerves. The V2 is a purely sensory nerve supplying the maxillary teeth and gingiva, the adjoining part of the cheek, hard and soft palate mucosa, pharynx, nose, dura mater, skin of temple, face, lower eyelid and conjunctiva, upper lip, labial glands, oral mucosa, mucosa of the maxillary sinus, as well as the mobile part of the nasal septum. The branches of the maxillary nerve can be divided into four groups depending on the place of origin i.e. in the cranium, in the sphenopalatine fossa, in the infraorbital canal, and on the face.

CONCLUSIONS

This review summarises the data on the anatomy and variations of the maxillary nerve and its branches. A thorough understanding of the anatomy will allow for careful planning and execution of anaesthesiological and surgical procedures involving the maxillary nerve and its branches.