Biomedical subjects

Albert L Rhoton

Publications and source records attributed to Albert L Rhoton.

15 recordsLinked to original sources

PubMed2003

Role of the zygomaticofacial foramen in the orbitozygomatic craniotomy: anatomic report.

OBJECTIVE: Elevation of the lateral orbital rim and zygomatic arch during an orbitozygomatic craniotomy requires a bone cut across the zygoma, which commonly extends into the lateral edge of the inferior orbital fissure. The zygomaticofacial foramen has been identified as a superficial landmark for the cut that extends into the inferior orbital fissure. This study examined the usefulness of the zygomaticofacial foramen during orbitozygomatic craniotomy. METHODS: One-hundred two dry hemicrania were used in this study. The zygomaticofacial foramen was considered to be related to the inferior orbital fissure when it was located on the zygoma in the area between lines extending in the medial-to-lateral direction along the long axis of the fissure and crossing the anterior and posterior ends of the lateral edge of the fissure. RESULTS: The zygomaticofacial foramen varied from being absent to representing as many as four small openings. A single foramen was observed in one-half of the specimens. Of the 115 zygomaticofacial foramina, 93 were related to the inferior orbital fissure. Among the 51 specimens with a single foramen, 49 foramina met the criteria for being related to the inferior orbital fissure; in those cases, there would have been no difference in the amount of bone resected using the inferior orbital fissure or the zygomaticofacial foramen as the landmark for the zygomatic cut. CONCLUSION: The zygomaticofacial foramen was a reliable landmark for locating the inferior orbital fissure and making the cut across the zygoma in only 50% of the specimens.

Brain Diseases↗

PubMed2003

Comparison of the far lateral and extreme lateral variants of the atlanto-occipital transarticular approach to anterior extradural lesions of the craniovertebral junction.

OBJECTIVE: Managing lesions situated in the anterior aspect of the craniovertebral junction (CVJ) remains a challenging neurosurgical problem. The purposes of this study were to examine the microsurgical anatomy of the anterior extradural aspect of the CVJ and the differences in the exposure obtained by the far lateral and extreme lateral atlanto-occipital transarticular approaches. The far lateral approach, as originally described, is a lateral suboccipital approach directed behind the sternocleidomastoid muscle and the vertebral artery and just medial to the occipital and atlantal condyles and the atlanto-occipital joint. The extreme lateral approach, as originally described, is a direct lateral approach deep to the anterior part of the sternocleidomastoid muscle and behind the internal jugular vein along the front of the vertebral artery. Both approaches permit drilling of the condyles at the atlanto-occipital joint but provide a different exposure because of the differences in the direction of the approach. METHODS: Fifteen adult cadaveric specimens were studied using a magnification of x3 to x40 after perfusion of the arteries and veins with colored silicone. The microsurgical anatomy of the extradural aspects of the CVJ and the two atlanto-occipital transarticular approaches were examined in stepwise dissections. RESULTS: The far lateral atlanto-occipital transarticular approach provides excellent exposure of the extradural lesions located in the ipsilateral anterior and anterolateral aspects of the extradural region of the CVJ. The extreme lateral atlanto-occipital transarticular approach provides excellent exposure, not only on the side of the exposure, but also extending across the midline to the medial aspect of the contralateral atlanto-occipital joint and the lower clivus. CONCLUSION: The far lateral and extreme lateral variants of the atlanto-occipital transarticular approach provide an alternative to the transoral approach to the anterior extradural structures at the CVJ. Compared with the transoral approach, both approaches provide a shorter operative route, avoid the contaminated nasopharynx, reduce the incidence of cerebrospinal fluid leak, and are not limited laterally by the atlanto-occipital joint.

Adult↗

PubMed2003

Microsurgical anatomy of the early branches of the middle cerebral artery: morphometric analysis and classification with angiographic correlation.

OBJECT: The cortical arteries arising from the main trunk of the middle cerebral artery, proximal to its bifurcation or trifurcation, are called "early branches." The purpose of this study was to characterize these early branches. METHODS: The early branches were characterized according to their sites and patterns of origin, diameters, and relative proximity to the internal carotid artery bifurcation, as well as the course and area of supply of their cortical branches based on an examination of 50 hemispheres. Special attention was directed to the perforating arteries that arose from the early branches and entered the anterior perforated substance. The anatomical findings were compared with data obtained from 109 angiograms. CONCLUSIONS: Early branches directed to the temporal and frontal lobes were found in 90 and 32% of the hemispheres, respectively. The early branches that arose more proximally from the M1 segment were larger than those arising distally. Lenticulostriate arteries arose from 81% of the early frontal branches (EFBs) and from 48% of the early temporal branches (ETBs). An average of two cortical arteries arose from the EFBs and 1.3 from the ETBs, the most common of which supplied the temporopolar and orbitofrontal areas. Although the microsurgical anatomy of the early branches demonstrates abundant diversity, they can be classified into clearly defined patterns based on anatomical features. These patterns can prove helpful in evaluating angiographic data and in planning an operative procedure.

Cadaver↗

PubMed2003

The transverse process, intertransverse space, and vertebral artery in anterior approaches to the lower cervical spine.

OBJECT: The microsurgical anatomy of the C3-6 transverse processes and their relationship to the intertransverse space and vertebral artery (VA) were examined with special attention to the aspect exposed in the anterior surgical approach. METHODS: Ten adult cadaveric spines were examined (magnification levels X 3-40) after perfusion of the arteries and veins with colored silicone. The morphological detail of the transverse process and intertransverse space, the distances between selected surgical landmarks and the VA were measured, and the means and standard deviations were calculated. The osseous changes in the anterior root of the transverse process were classified according to their extent. The transverse processes became smaller, and the anterior intertransverse spaces and the width of the VA exposed in the space increased in size proceeding from caudal to rostral levels, thus exposing the VA to increased risk of injury during procedures at cephalad levels. The distance between the medial border of the longus colli muscle and the VA decreased when proceeding caudally from C2-3 to C4-5 interspaces but began to increase at the level of C5-6. The VA coursed closer to the lateral border of the vertebral body than to the medial border of the anterior tubercle of transverse process. Osseous changes consisting of thinning or defects in the anterior root of the transverse process were observed from C-3 to C-5. The thinning was most prominent in the lower half of the anterior root just above where the VA ascends behind the lower edge of the anterior root. The osseous change may reflect the erosive effect of the VA on the anterior root of the transverse process. CONCLUSIONS: This study provides new information regarding the transverse process and especially the anterior root. An awareness of the thinness and defects in the anterior root of the transverse process and the relationships to the surrounding area will aid in reducing VA injury during anterior approaches to the cervical spine.

Adult↗

PubMed2002

The cerebrum.

Explore the source record for details and available documents.

Cerebral Aqueduct↗

PubMed2002

Comparison of posterior approaches to the posterior incisural space: microsurgical anatomy and proposal of a new method, the occipital bi-transtentorial/falcine approach.

OBJECTIVE: Direct surgical approaches to the posterior incisural space, including the pineal region, remain as challenges for neurosurgeons. The purposes of this study were 1) to compare the surgical views in the various posterior approaches to the posterior incisural space and 2) to propose a new approach, which is a modification of the occipital transtentorial approach. METHODS: Ten adult cadaveric specimens (20 sides) were studied, using x3 to x40 magnification, after perfusion of the arteries and veins with colored silicone. Intraoperative views in the posterior approaches to lesions were examined in stepwise dissections. In addition, the efficacy of the occipital bi-transtentorial/falcine approach was studied. RESULTS: The posterior incisural space has a roof, a floor, and anterior and lateral walls and extends backward to the level of the tentorial apex. The operative views defined by each approach differ in the extent to which they allow observation of the anatomic structures in the posterior incisural space. The occipital bi-transtentorial/falcine approach permits better observation of the contralateral half of the quadrigeminal cistern. CONCLUSION: Precise surgical anatomic knowledge of each approach is required for the treatment of lesions in the posterior incisural space, because the operative fields obtained with different approaches differ significantly. The occipital bi-transtentorial/falcine approach provides greater contralateral exposure of the posterior incisural space than does the occipital transtentorial approach.

Adult↗

PubMed2002

[Microsurgical anatomy of the perforating arteries on the third ventricular floor].

OBJECTIVE: To study the microvascular anatomy of the perforating arteries on the third ventricular floor. METHODS: The microanatomy of perforating arteries on the third ventricular floor in 25 cadaveric heads of adults was observed with 4 to 40-power surgical microscope. RESULTS: The perforating arteries on the third ventricular floor arose from the internal carotid, posterior communicating, posterior cerebral and basilar arteries, and could be divided into three patterns: no ramification, proximal ramification, and distal ramification, according to their vascular origin and course. The perforating arteries of proximal ramification pattern had larger diameter and broader distribution These perforating arteries terminated at relative distant area, including a) anterior part: the optic chiasm and stalk and infundibulum; b) middle part: mamillary body and tuber cinereum; c) posterior part: posterior perforated substance and posterior fossa; and d) lateral part: paramedian perforated substance and anterior portion of optic tract. In middle part overlap and anastosis of perforating artery with posterior communicating artery from both sides were relatively few. CONCLUSION: The perforating arteries on the third ventricular floor can be divided into three patterns. The proximal ramification pattern possesses larger diameter of the vessel and broader blood supply area on the third ventricular floor. Identification and preservation of these perforating arteries are important when surgery is being planed.

Cerebral Arteries↗

PubMed2002