Location of Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) in Zone III Using External Landmark Without Fluoroscopy: A CTA-based Retrospective Study

Background Resuscitative endovascular balloon occlusion of the aorta (REBOA) can timely prevent the wounded from massive hemorrhage. We aim to study whether the combination of the xiphoid process and the umbilicus could guide the placement of REBOA in zone III without fluoroscopy. Methods We conducted a retrospective study in a university hospital that included 57 subjects who underwent contrast-enhanced computed tomography (CT) from April to December in 2019. External distances and intravascular lengths were measured by three-dimensional reconstruction CT images on the workstation, including the distances from the femoral artery to the xiphoid process (FA-Xi), the midpoint between the xiphoid process and the umbilicus (FA-mXU), the umbilicus (FA-Ui), the midpoint of the zone III (FA-mZIII), the lowest renal artery (FA-LRA), and aortic bifurcation (FA-AB). The relationship between external landmarks and REBOA catheter positioning in zone III was studied, involving the quartering distances between the xiphoid process and the umbilicus, the distance below the xiphoid process and that above the umbilicus. The predicted accuracy and safety margin of the balloon (distal and proximal) were calculated by curvature plane reconstruction. The probability of balloon positioning in zone III using these three methods was compared by Chi square test. Results The average length of aortic zone III was 9.4 cm (SD = 10.0), and that of FA-mZIII on the right and left sides were 24.4 cm (SD = 2.1) ,23.8 cm (SD = 2.1), respectively. FA-Xi was significantly longer than FA-LRA, and FA-Ui was significantly shorter than FA-AB (P < 0.05). Using the quartering distances between the xiphoid and the umbilicus, the distance below the xiphoid, the distance above the umbilicus to predict the length of REBOA catheter positioning in zone III showed no statistically significant difference. Using FA-mXU to predict the accuracy of catheter positioning in zone III on the left and right sides were 84.2% and 86%. Although there was a little difference between the left side of FA-mZIII and FA-mXU, there were no statistical differences on the right side. Conclusions The midpoint between the xiphoid process and the umbilicus is a good external landmark to guide the placement of REBOA in zone III without fluoroscopy.

A lateral approach to the feline cerebellar fossa: case report and identification of an external landmark for the tentorium ossium

Objectives The aim of this study was to describe the use of an external landmark that defines the attachment of the tentorium ossium for planning a craniectomy to access the cerebellar fossa. The external landmark was defined by a line where the caudal aspect of the convexity of the cranium transitions to a flat surface in the caudal aspect of the temporal fossa. We also aimed to determine if this external landmark was present and readily visualized, and to establish its relationship to the nuchal crest using three-dimensional (3D) volume-rendered CT reconstructions created from cats with normal cranial morphology. Methods First, a case is presented for the description of an approach in a cat with a meningioma located dorsolateral to the cerebellum. Second, CT studies of five cats with normal cranial morphology were selected. Regions of interest (ROIs) were drawn at the attachment of the tentorium ossium to the cranium and nuchal crest. Three-dimensional reconstructions were developed with colored ROI overlays. The external landmark defined the tentorial attachment on all 3D reconstructions. Additionally, using the postoperative CT of the clinical case described herein, ROIs of the tentorial attachment and nuchal crest along with a third ROI, the craniectomy, were drawn and overlaid on the 3D reconstruction to illustrate the position of the craniectomy in relation to the tentorium ossium attachment and nuchal crest. Results The use of the external landmark provided for a craniectomy that enabled adequate visualization for excision of a meningioma. On all 3D reconstructions, the external landmark was present and readily visualized. Conclusions and relevance Between the attachment of the tentorium ossium and nuchal crest exists an area adequately sized for a craniectomy in cats. Clinicians can use an identifiable external landmark on the lateral aspect of the cranium to plan the rostral boundary for a craniectomy to access the cerebellar fossa in cats.

Of Horse-Caterpillars and Homologies: Evolution of the Hippocampus and Its Name

The hippocampus was first named in mammals based on the appearance of its gross morphological features, one end of it being fancied to resemble the head of a horse and the rest of it a silkworm, or caterpillar. A hippocampus, occupying the most medial part of the telencephalic pallium, has subsequently been identified in diverse nonmammalian taxa, but in which the “horse-caterpillar” morphology is lacking. While some strikingly similar functional similarities have been identified, questions of its homology (“sameness”) across these taxa and about the very fundamental relationship of structure to function in central nervous system structures remain open. The hippocampal formation of amniotes participates in allocentric (external landmark) spatial navigation, memory, and attention to novel stimuli, and these functions generally are shared across amniotes despite variation in its morphological features. Substantially greater deviation in its morphology occurs in anamniotes, including amphibians and ray-finned fishes (actinopterygians), but its functions of allocentric spatial navigation and/or memory have been found to be preserved by studies in these taxa. Its shared functional roles cannot be used as evidence of structural homology, but given that other criteria indicate homology of the medial pallial derivative across these clades, the similar functions themselves may be regarded as homologous functions if they are based on the same cellular mechanisms and connections. The question arises as to whether the similar functions are performed by as yet undiscovered, shared morphological features or by different features that accomplish the same results via different mechanisms of neural function.

A New External Landmark for Mental Foramen

ABSTRACT Purpose The purpose of this study was to establish a new external landmark of mental foramen to help facilitate prediction of the location during local anesthesia and during surgery of mandibular region. Materials and methods One hundred and ten adult Thai cadavers of 61 males and 49 females from Department of Anatomy, Faculty of Science, Mahidol University were included in this study. The anatomy of mental foramen in 110 adult Thai cadavers (220 sides) was studied from 2008 until 2011. Measurements in vertical plane were made: (i) From gingival sulcus to mental foramen = A, (ii) from mental foramen to inferior border of mandible = B, and (iii) the ratio of A/A + B = D. Measurements in horizontal plane were also made: (i) From symphysis menti to the mental foramen = S (in straight line and not related to mandibular curvature), and (ii) from symphysis menti to the mental foramen = C (in curved line related to mandibular curvature), and (iii) in relation to position of lower tooth/teeth, and (iv) in relation to cheilions (corners of the mouth). Results The results included 61 male and 49 female cadavers. On the right side, the proportion of A/A + B (D) of male and female was 0.50 and 0.46. On the left side, the proportion of A/A + B (D) of male and female was 0.50 and 0.46. The location of right and left cheilion was related with the position of mental foramen, mostly at center (male: 63.93 and 70.49%, female: 61.22 and 73.47%). If center ± 0.3 cm it was possible to find the mental foramen more easily than the point of the center (male: 95.08 and 91.80%, female: 87.76 and 93.88%). If center ± 0.5 cm, it could find the mental foramen more easily than the point of the center ± 0.3 cm (male: 98.36 and 98.36%, female: 95.92 and 97.96%). Conclusion The knowledge gained from this study is quite important, since it helps the surgeon to easily identify the mental foramen prior to surgery which is halfway between gingival sulcus and inferior border of mandible in vertical plane and at the cheilion position in horizontal plane. How to cite this article Tungkeeratichai J, Bhongmakapat T, Saitongdee P, Orathai P. A New External Landmark for Mental Foramen. Int J Otorhinolaryngol Clin 2013;5(1):29-33.

A New External Landmark for Mental Foramen

ABSTRACT Purpose The purpose of this study was to establish a new external landmark of mental foramen to help facilitate prediction of the location during local anesthesia and during surgery of mandibular region. Materials and methods One hundred and ten adult Thai cadavers of 61 males and 49 females from Department of Anatomy, Faculty of Science, Mahidol University were included in this study. The anatomy of mental foramen in 110 adult Thai cadavers (220 sides) was studied from 2008 until 2011. Measurements in vertical plane were made: (i) From gingival sulcus to mental foramen = A, (ii) from mental foramen to inferior border of mandible = B, and (iii) the ratio of A/A + B = D. Measurements in horizontal plane were also made: (i) From symphysis menti to the mental foramen = S (in straight line and not related to mandibular curvature), and (ii) from symphysis menti to the mental foramen = C (in curved line related to mandibular curvature), and (iii) in relation to position of lower tooth/teeth, and (iv) in relation to cheilions (corners of the mouth). Results The results included 61 male and 49 female cadavers. On the right side, the proportion of A/A + B (D) of male and female was 0.50 and 0.46. On the left side, the proportion of A/A + B (D) of male and female was 0.50 and 0.46. The location of right and left cheilion was related with the position of mental foramen, mostly at center (male: 63.93 and 70.49%, female: 61.22 and 73.47%). If center ± 0.3 cm it was possible to find the mental foramen more easily than the point of the center (male: 95.08 and 91.80%, female: 87.76 and 93.88%). If center ± 0.5 cm, it could find the mental foramen more easily than the point of the center ± 0.3 cm (male: 98.36 and 98.36%, female: 95.92 and 97.96%). Conclusion The knowledge gained from this study is quite important, since it helps the surgeon to easily identify the mental foramen prior to surgery which is halfway between gingival sulcus and inferior border of mandible in vertical plane and at the cheilion position in horizontal plane.

Refined and Simplified Surgical Landmarks for the MacCarty Keyhole and Orbitozygomatic Craniotomy

BACKGROUND Precise placement of the MacCarty keyhole, a burr hole simultaneously exposing the anterior cranial fossa floor and orbit, provides accurate, efficient entry for orbitozygomatic and supraorbital craniotomies. To locate the optimal keyhole site, previous studies have used superficial landmarks that, in our experience, are not always visible or consistent on older crania. OBJECTIVE Therefore, we present a technique for accurate keyhole placement using landmarks that are easily visible across age ranges. METHODS From inside the cranium, 1-mm burr holes were placed along the anterior junction of the floor and lateral wall of the anterior cranial fossa in 50 adult skulls (100 sides, with calvaria removed). Additionally, from inside the orbit, 1-mm burr holes were placed into the lateral orbital roof. Exit sites of intracranial and intraorbital burr holes were referenced to the frontozygomatic suture. The center of the site between the exiting intracranial and intraorbital holes was deemed the best location for the keyhole. RESULTS The keyhole center was 6.8 mm (mean) superior and 4.5 mm (mean) posterior to the frontozygomatic suture, which was easily identified on all specimens. Although this keyhole center was slightly more superior on right sides than left, this was not statistically significant. In a minority of specimens, the keyhole was located near the meningo-orbital foramen (22%) and the lateral extent of the frontal sinus (2%). CONCLUSIONS We defined an alternative method for locating the MacCarty keyhole, based on a reliable external landmark, approximately 7 mm superior and 5 mm posterior to the frontozygomatic suture.

Comparison Between Effect of Head Positions on the Placement of Catheter in the Internal Jugular Vein

The position of the head of the patient play an important role in the ease and success of Right Internal Jugular Vein (RIJV) cannulation using external landmark-guided technique. Sixty patients undergoing open heart surgery for both acquired and congenital heart diseases were studied in three groups-neutral head position, head rotated to 20 degree and head rotated to 30 degree to the left for RIJV cannulation. The overall success rate irrespective of number of attempts and head positions in this study was 93.3%. Complications were a bit higher than in other studies. Available literature did not compare between different degree of position of head rotation. This study compared between these groups in terms of number of attempts required for RIJV cannulation, but no significant difference was found between or within the groups (P>0.05). From this study it can be proposed that, some degree of rotation (upto 20 degree) may be allowed to make landmark prominent but extreme degree of rotation which result in more number of attempts and complications is not desired. Journal of BSA, Vol. 20, No. 2, July 2007 p.56-60