Saad Al-Ali

Anatomical variations of the common carotid artery bifurcation

Background:  The correlation of the common carotid artery (CCA) bifurcation and its surrounding structures is poorly described. The aim of this study was to describe the anatomy of the CCA bifurcation relative to its surrounding structures.

Microstructure of the vocal fold in elderly humans

Significant changes in the voice occur after the age of 50 years. Changes in the structure of the vocal fold (VF) can interfere with the voice. The aim of this study is to investigate the structure of the VF of elderly people that may contribute to the tendency of the human voice to deteriorate. Larynges were obtained from eight embalmed cadavers aged 72–98 years. The middle portion of each vocal fold was removed and placed in 4% buffered formalin. Tissue blocks were then processed and embedded in wax. Four to six micron coronal sections were cut and stained with Haematoxylin and Eosin (H&E), Massons Trichrome (MTS), Elastin van Gieson (EVG), Herovici (HERO), picrosirius and CD31 immunohistochemical marker in order to study the collagen fibers, elastic fibers and microvasculature of the VF. The maturity of collagen fibers within the VF were noted to increase from the superficial to the deep layer of the lamina propria (LP). Contrary to current literature, the amount of elastic fibers was sparse in the superficial layer of the LP in the vocal tissue of elderly cadavers. Numerous cross‐sectioned blood vessels were seen in the lamina propria near the free edge, and near the superior and inferior surfaces of the VF. The presence of lymphatic vessels was confirmed in the VF of elderly subjects. This study revealed that the collagenous component of the deep layer of the VF LP was made up of mature fibers whilst immature collagen fibers made up the superficial layer of the LP. There was a notable scarcity of elastic fibers in the superficial layer of the LP. Lymphatics were seen and were orientated differently in the geriatric vocal folds. Clin. Anat. 24:544–551, 2011.

Correlation between gross anatomical topography, sectional sheet plastination, microscopic anatomy and endoanal sonography of the anal sphincter complex in human males

This study elucidates the structure of the anal sphincter complex (ASC) and correlates the individual layers, namely the external anal sphincter (EAS), conjoint longitudinal muscle (CLM) and internal anal sphincter (IAS), with their ultrasonographic images. Eighteen male cadavers, with an average age of 72 years (range 62–82 years), were used in this study. Multiple methods were used including gross dissection, coronal and axial sheet plastination, different histological staining techniques and endoanal sonography. The EAS was a continuous layer but with different relations, an upper part (corresponding to the deep and superficial parts in the traditional description) and a lower (subcutaneous) part that was located distal to the IAS, and was the only muscle encircling the anal orifice below the IAS. The CLM was a fibro‐fatty‐muscular layer occupying the intersphincteric space and was continuous superiorly with the longitudinal muscle layer of the rectum. In its middle and lower parts it consisted of collagen and elastic fibres with fatty tissue filling the spaces between the fibrous septa. The IAS was a markedly thickened extension of the terminal circular smooth muscle layer of the rectum and it terminated proximal to the lower part of the EAS. On endoanal sonography, the EAS appeared as an irregular hyperechoic band; CLM was poorly represented by a thin irregular hyperechoic line and IAS was represented by a hypoechoic band. Data on the measurements of the thickness of the ASC layers are presented and vary between dissection and sonographic imaging. The layers of the ASC were precisely identified in situ, in sections, in isolated dissected specimens and the same structures were correlated with their sonographic appearance. The results of the measurements of ASC components in this study on male cadavers were variable, suggesting that these should be used with caution in diagnostic and management settings.

Three-Dimensional High-Resolution Reconstruction of the Human Gastro-Oesophageal Junction

The aim of this study was to obtain detailed information regarding the three‐dimensional structure of the gastro‐oesophageal region, and, in particular, the fiber orientation of the different muscle layers of the junction. This was achieved by a study of an en bloc resection of the gastro‐oesophageal junction (GOJ) harvested from a human cadaver. The excised tissue block was suspended in a cage to preserve anatomical relationships, fixed in formalin and embedded in wax. The tissue block was then processed by a custom‐built extended‐volume imaging system to obtain the microstructural information using a digital camera which acquires images at a resolution of 8.2 μm/pixel. The top surface of the tissue block was sequentially stained and imaged. At each step, the imaged surface was milled off at a depth of 50 μm. The processing of the tissue block resulted in 650 images covering a length of 32.25 mm of the GOJ. Structures, including the different muscle and fascial layers, were then traced out from the cross‐sectional images using color thresholding. The traced regions were then aligned and assembled to provide a three‐dimensional representation of the GOJ. The result is the detailed three‐dimensional microstructural anatomy of the GOJ represented in a new way. The next stage will be to integrate key physiological events, including peristalsis and relaxation, into this model using mathematical modeling to allow accurate visual tools for training health professionals and patients. Clin. Anat. 23:287–296, 2010.

Postmortem investigation of mylohyoid hiatus and hernia: Aetiological factors of plunging ranula

The mylohyoid hiatus and hernia were discovered in the nineteenth century and were considered to explain the origin of the plunging ranula from the sublingual gland. This formed the rationale for sublingual sialadenectomy for the treatment of plunging ranula. However, a more recent, extensive histological investigation reported that hernias contained submandibular gland, which supported an origin of the plunging ranula from the submandibular gland and submandibular sialadenectomy for the treatment of plunging ranula. We therefore decided to investigate the occurrence and location of the hiatus and the histological nature of the hernia. Twenty‐three adult cadavers were dissected in the submandibular region. The locations and dimensions of mylohyoid hiatuses were measured before taking biopsies of hernias. Hiatuses with associated hernias were found in ten cadavers: unilateral in six; and bilateral in four, in one of which there were three hiatuses. Sublingual gland was identified in nine hernias and fat without gland in six. This investigation supports clinical and experimental evidence that the plunging ranula originates from the sublingual gland and may enter the neck through the mylohyoid muscle. It confirms the rationale of sublingual sialadenectomy for the treatment of plunging ranula. Clin. Anat. 26:693–699, 2013.

Surgical anatomy of the external branch of the superior laryngeal nerve

Background:  The variations in the anatomy of the external branch of the superior laryngeal nerve (EBSLN) are generally classified according to the relationship of the nerve to the superior thyroid artery, or the superior pole of the thyroid. Both artery and superior pole are themselves variable landmarks, and therefore are not consistent between subjects. We sought to examine EBSLN anatomy in relation to alternate, more consistent surgical landmarks.

Superior oblique muscle palsy after frontal sinus mini-trephine

OBJECTIVE The aim of this study is to present a case of superior oblique muscle dysfunction after a frontal sinus mini-trephine. METHODS This is a case report of an 18-year-old woman where a mini-trephination approach and endoscope were used to open and marsupialize a symptomatic, opacified type IV cell within the left frontal sinus. After surgery, the patient developed a persisting diplopia; a left superior oblique muscle palsy was diagnosed. Nine cadaveric dissections of the trochlea were undertaken to clarify mechanisms for potential trochlear damage. RESULTS Cadaveric dissection reveals that the trochlea is more than a simple pulley; it is a complex structure in close proximity to the orbital rim. The superior oblique tendon telescopes and is surrounded by a vascular sheath that could be easily traumatized. CONCLUSION Damage to the trochlea could occur, as the periosteum is elevated from bone or during healing. Alternatively, prolonged traction on soft tissue near the trochlea could cause swelling of the vascular sheath, fibrosis, and hypomobility of the superior oblique tendon. Careful siting of the incision for external frontal sinus surgery as well as careful retraction of skin flaps and periosteal elevation are all techniques used, which should reduce the risk of damage to the trochlea.

Adequacy of brain and spinal blood supply with antegrade cerebral perfusion in a rat model

OBJECTIVE The purpose of this study was to examine whether different techniques used for antegrade cerebral perfusion could account for variation in the perfusion adequacy of the brain and spinal cord. METHODS Selected vessels were ligated in 30 rats, recreating a selection of approaches used in aortic arch surgery for patients undergoing circulatory arrest with antegrade cerebral perfusion. Filling of spinal and cerebral vessels was mapped after cannulation and perfusion with E20, gelatin/India ink, or buffered saline/India ink. Three clinical approaches were replicated: unilateral perfusion, bilateral perfusion, and bilateral perfusion with additional left subclavian artery perfusion. Filling of the spinal arteries via the common carotid arteries or the subclavian arteries alone was examined. Penetration of the marker was analyzed histologically. RESULTS The control experiments achieved maximal arterial filling of both brain and spinal cord at gross and microscopic levels. Unilateral and bilateral antegrade cerebral perfusion provided comprehensive arterial filling of all cerebral vessels with all vascular markers. In contrast, only bilateral antegrade cerebral perfusion provided complete spinal cord perfusion with all markers. Unilateral antegrade cerebral perfusion with a viscous marker resulted in significantly reduced spinal cord arterial filling. Examination of the relative importance of either both common carotid arteries alone or both subclavian arteries alone, in terms of their adequacy of subsequent arterial filling of the spinal cord, showed severe impairment of spinal cord perfusion with either technique. Thus perfusion of both common carotid arteries resulted in only the proximal 30% of the spinal cord arteries being filled, whereas perfusion of both subclavian arteries resulted in only the proximal 40% of the spinal cord arteries being filled. CONCLUSIONS Approaches to antegrade cerebral perfusion using the brachiocephalic and left common carotid arteries together gave good perfusion of both the brain and the spinal cord. Brachiocephalic perfusion alone gave good cerebral perfusion but showed some significant limitation in spinal cord perfusion with one vascular marker. Complete spinal cord perfusion with all markers under conditions of antegrade cerebral perfusion required some contribution from both the carotid system and the subclavian system together. Selected perfusion of either system alone was very inadequate for spinal cord perfusion.

HP12 THE ANATOMICAL BASIS OF THE SURGICAL TREATMENT OF GASTRO‐OESOPHAGEAL REFLUX: LESSONS FROM HISTORY AND SIMULATION

Purpose  To review the anatomical basis for anti‐reflux operations and describe a project designed to develop a 3D micro‐anatomical model of the gastro‐oesophageal junction with integrated physiological events.