VARIANTS OF MASTOID AND OCCIPITAL EMISSARY FORAMENS AND THEIR CLINICAL CORRELATION

Purpose: Emissary foramens in the skull and emissary veins (EV), respectively, have been known for a long time, but their importance is often disregarded. In the present study, we introduce variants of occipital emissary foramens (OEF) unilaterally located on the left, close to оccipital condylе in a formation of three apertures that open together in a sinus near clivus. Material/Methods: Corpses of 30 dеad people were dissected in the Department of Anatomy, and standard techniques for soft tissue separation or maceration of the skull were used. After the removal of the calvaria, fixed bones of the skull were disarticulated. Foramens were cleaned using a double-ended probe, and depth and diameter measurements were performed using an atomical caliper. Results: We found variants of mastoid emissary foramens (MEF) situated into two groups, each of a couple of foramens. Their clinical significance is discussed, compared with existing experience and analysis of their phylogeny and embryogenesis. Conclusion: We introduce OEF and MEF to be important markers for detection of dural venous sinuses (DVS). The latter, together with EV, provide an important mechanism for decreasing intracranial pressure. This happens due to the absence of a valve apparatus in the veins of the brain, and the lack, or small amount, of muscle tissue. There is a possibility of existing varicose veins, such as those caused by arterio-venous fistulas and the pathology associated with it. We suggest the application of EV in imaging as an important study before surgery by lateral and transcondylar approach to the anterior foramen magnum.

Single incision endoscopic strip craniectomy for sagittal craniosynostosis

The authors describe an endoscopic strip craniectomy through a single incision for the treatment of sagittal craniosynostosis in a young infant. The endoscopic strip craniectomy was first introduced with the use of two incisions on either end of the fused suture. This single-incision technique offers several advantages. There is a cosmetic advantage and a reduced risk of wound complications. This technique also allows for early control of emissary veins and an inside-out identification of the lambdoid sutures. Endoscopic visualization is optimized to reduce the risk of blood loss, especially because circulating blood volume is very limited in these young infants. The video can be found here: https://vimeo.com/514366415

Metopic triangle osteotomy in trigonocephaly Piezosurgery: a technical variant to control metopic emissary veins

Premature fusion of the metopic suture results in trigonocephaly with variable degrees of anterior cranial fossa dysmorphia and craniofacial deformity. Different surgical corrective techniques that aim to reshape the forehead and enlarge the cranial volume have been described. Typical variations of the standard fronto-orbitary advancement carry the risk of relevant blood loss during frontal osteotomy, where paired emissary metopic veins are disrupted. The authors present a technical variant that preserves a bony triangle over the glabella to optimize control of these veins, which represent the major source of bleeding, and applies Piezosurgery to perform the osteotomies to minimize bone substance loss. The video can be found here: https://vimeo.com/511536423.

Dural venous system: angiographic technique and correlation with ex vivo investigations

BackgroundThe dural vasculature plays a key role in several important conditions, including dural fistulas and subdural collections. While in vivo investigations of intrinsic dural arterial angioarchitecture are rare, no angiographic studies of dural venous drainage exist to our knowledge.ObjectiveTo describe methods by which dural venous drainage might be visualized with current angiographic equipment and technique, and to correlate our results with existing ex vivo literature.MethodsDigital subtraction angiography and 3D angiography (rotational and Dyna CT) of dural neurovasculature were acquired in the context of subdural hematoma embolization and normal dura. Protocols for visualization of dural venous drainage were established, and findings correlated with ex vivo studies.ResultsMeningeal arteries supply both the skull and dura. Normal dural enhancement is accentuated by the presence of hypervascular membranes. Intrinsic meningeal veins/sinuses parallel outer layer arteries with well-known tram-tracking appearance. Dura adjacent to main arterial trunks drains via skull base foramina into the pterygopalatine venous plexus, or via emissary veins into the temporalis venous plexus. Dura near the sinuses drains into venous pouches adjacent to the sinus, before emptying into the sinus proper—possibly the same pouches implicated in the angioarchitecture of dural fistulas. Finally, posterior temporoparietal convexity dura, situated in a watershed-like region between middle and posterior meningeal territories, frequently empties into diploic and emissary veins of the skull. Wide variation in balance is expected between these three routes. Drainage patterns appear to correlate with venous embryologic investigations of Padget and ex vivo studies in adults.ConclusionsContinued attention to dural venous drainage may prove useful in the diagnosis and management of dural-based vascular diseases.

Morphological study of foramen venosum in dry human skulls in Northeast Brazil

Introduction: The foramen venosum (FV) is located in the larger wing of the sphenoid bone and allows the passage of emissary veins that help to balance the intra and extracranial pressure. Knowledge of its morphology and associated structures has an important surgical value. Objective: Analyze the morphology of FV and its relation to adjacent foramina in Northeast Brazil. Methods: 117 human adult skulls of Federal University of Paraíba were classified by gender, FV type and laterality, being evaluated the diameter of FV, foramen ovale (FO) and foramen spinosum (FS), as well as the distance of FO and FS to FV (DFVFO and DFVFS). Values of p≤0.05 were considered significant. Results: 52 (44.4%) skulls (65 sides, 29 on the right and 36 on the left) presented FV, being 63.46% females and 36.53% males. 33.3% of FV were unilateral and 11.1% were bilateral. The FV were mostly oval (50.7%) and round (49.3%) types. Mean diameter of FV was 3.56±0.7mm, FO 7.88±1.16mm, FS 4.01±0.39mm, DFVFO 8.18±1.09mm and DFVFS was 14.54±1.68mm. Only FO (p=0.009) and FS (p=0.001) had significant differences between genres, and DFVFO had among sides (p=0.021). Conclusions: FV has a high incidence in Northeast Brazil, predominantly in females on the left side with oval and round types. Its relation with other foramina showed differences among genres and sides. This shows the relevance of the FV study to minimize the risk of iatrogenic injury during surgical interventions in this region.

Endovascular coiling of large mastoid emissary vein causing pulsatile tinnitus

The association of large mastoid emissary veins and pulsatile tinnitus has been reported. However, therapeutic options for this condition remain limited. We report a case of endovascular coiling of a large mastoid emissary vein in a patient with disabling pulsatile tinnitus with significant improvement of symptoms. To our knowledge, endovascular coiling of large mastoid emissary vein causing pulsatile tinnitus has not been reported.

POST-GLENOID FORAMEN: A RARE EMISSARY FORAMEN IN HUMAN SKULL

Objective: The aim of the present study was to determine the presence of post-glenoid foramen in human skulls. Methods: The study was carried out in 100 adult dry human skulls with 200 temporal bones on each side (right and left) which were collected from the Department of Anatomy at RVS Dental College and Hospital, Coimbatore. The selected skulls were placed on a flat table and the considerable foramen was visually identified by two investigators. The foramen was examined by a probing method to find out its patency. Results: Of 100 skulls (200 temporal bones), only one skull showed a unilateral post-glenoid foramen on the mandibular fossa of the left side temporal bone (2% of 200). Conclusion: The emissary veins are considered as an important encephalic venous drainage that connects the intracranial and extracranial venous pathway through emissary foramen. If there is little variation, and rare occurrence of the emissary foramen may cause serious pathological condition. Thereby, the present study highlights one of the rare emissary foramen, the post-glenoid foramen. This anatomical study of post-glenoid foramen may help the surgeons while operating temporomandibular joint and inner ear malformation to avoid the risk of accidental bleeding during surgery.