Main Anatomical Landmarks Research Articles

Extended endoscopic endonasal posterior (transclival) approach to tumors of the clival region and ventral posterior cranial fossa. Part 2. Topographic and anatomical aspects and surgical technique

to present the main topographic and anatomical features of the clivus and adjacent structures for improving and optimizing the extended endoscopic transnasal posterior (transclival) approach in removal of clival and ventral posterior cranial fossa lesions. We performed a topographic and anatomical study of 25 cadaver heads, the vascular bed of which was filled with colored silicone using the original technique for visualizing the bed features and individual variability. We present the main anatomical landmarks necessary for performing the extended endoscopic endonasal posterior approach. Superior, medial, and inferior transclival approaches provide access to the anterior surface of the upper, middle, and lower neurovascular complexes of the posterior cranial fossa. The endoscopic transclival approach can be used to reach ventral posterior cranial fossa lesions. The endoscopic transnasal transclival approach is an alternative to transcranial approaches to clival lesions.

Extended endoscopic endonasal posterior (transclival) approach to tumors of the clival region and ventral posterior cranial fossa. Part 1. Topographic and anatomical features of the clivus and adjacent structures

to describe the main topographic and anatomical features of the clival region and its adjacent structures for improvement and optimization of the extended endoscopic endonasal posterior (transclival) approach for resection of tumors of the clival region and ventral posterior cranial fossa. We performed a craniometric study of 125 human skulls and a topographic anatomical study of heads of 25 cadavers, the arterial and venous bed of which was stained with colored silicone (the staining technique was developed by the authors) to visualize bed features and individual variability. Currently, we have clinical material from more than 120 surgical patients with various skull base tumors of the clival region and ventral posterior cranial fossa (chordomas, pituitary adenomas, meningiomas, cholesteatomas, etc.) who were operated on using the endoscopic transclival approach. We present the main anatomical landmarks and parameters of some anatomical structures that are required for performing the endoscopic endonasal posterior approach. The anatomical landmarks, such as the intradural openings of the abducens and glossopharyngeal nerves, may be used to arbitrarily divide the clival region into the superior, middle, and inferior thirds. The anatomical landmarks important for the surgeon, which are detected during a topographic anatomical study of the skull base, facilitate identification of the boundaries between the different clival portions and the C1 segments of the internal carotid arteries. The superior, middle, and inferior transclival approaches provide an access to the ventral surface of the upper, middle, and lower neurovascular complexes in the posterior cranial fossa. The endoscopic transclival approach may be used to access midline tumors of the posterior cranial fossa. The approach is an alternative to transcranial approaches in surgical treatment of clival region lesions. This approach provides results comparable (and sometimes better) to those of the transcranial and transfacial approaches.

Основные анатомические ориентиры для протезирующей хирургической реконструкции тазового дна вагинальным доступом

Основные анатомические ориентиры для протезирующей хирургической реконструкции тазового дна вагинальным доступом

The Inferolateral Transorbital Endoscopic Approach: A Preclinical Anatomic Study

In recent years, transorbital endoscopic approaches are increasing in popularity as they provide several corridors to reach lateral areas of the ventral skull base through the orbit. The aim of this study is to investigate the feasibility of the inferolateral transorbital endoscopic approach (ILTEA) by detailing the step-by-step dissection, anatomic landmarks, and target anatomic areas. Seven cadaveric specimens (14 sides) were dissected in the Laboratory of Endoscopic Anatomy of the University of Brescia. Step-by-step dissection of ILTEA was performed to identify the main anatomic landmarks and corridors. Skin incision, dural incision, and boundaries of craniectomy were measured. Neuronavigation was used to check landmarks, track boundaries of surgical volumes, and measure orbital dislocation. The study on the 14 ILTEAs defined 1 anatomic area ("waterline door") that leads to 4 corridors: Meckel's cave corridor, carotid foramen corridor, petrous corridor, and transdural middle fossa corridor. Crucial anatomic landmarks were identified and analyzed. Orbital dislocation was <10 mm. ILTEA provides the surgeon with a direct route to the region of the "waterline door," lateral areas of the ventral skull base, and middle cranial fossa. In addition, it allows an optimal view of the intracranial and extracranial portions of the maxillary and mandibular nerves. Further anatomic and clinical studies are needed to validate ILTEA in surgical practice.

Normalizing videos of anterior eye segment surgeries.

Anterior eye segment surgeries are usually video-recorded. If we are able to efficiently analyze surgical videos in real-time, new decision support tools will emerge. The main anatomical landmarks in these videos are the pupil boundaries and the limbus, but segmenting them is challenging due to the variety of colors and textures in the pupil, the iris, the sclera and the lids. In this paper, we present a solution to reliably normalize the center and the scale in videos, without explicitly segmenting these landmarks. First, a robust solution to track the pupil center is presented: it uses the fact that the pupil boundaries, the limbus and the sclera / lid interface are concentric. Second, a solution to estimate the zoom level is presented: it relies on the illumination pattern reflected on the cornea. The proposed solution was assessed in a dataset of 186 real-live cataract surgery videos. The distance between the true and estimated pupil centers was equal to 8.0 ± 6.9% of the limbus radius. The correlation between the estimated zoom level and the true limbus size in images was high: R = 0.834.

Cystocele repair with single-incision, trocarless mesh system

The use of mesh at the time of anterior vaginal wall repair reduced the risk of recurrent anterior vaginal wall prolapse. The aim of our video is to demonstrate our dissection technique focusing on the main anatomical landmarks in the pelvis and present an overall safer system to correct pelvic floor prolapse. The video demonstrates correction of cystocele with the EndoFast Reliant™ system (IBI Israel Biomedical Innovations, Caesarea Industrial Park South, Israel). The surgical technique is described. Twenty-nine patients were treated with the system. Mean follow-up was 10 (range, 6-30) months. At latest follow-up, favorable anatomical results were obtained for 26 of 29 patients (89.6 %); three patients presented stage 1 nonsymptomatic prolapse. Three cases (13 %) of de novo stress urinary incontinence (SUI) and two cases of de novo urgency (6.9 %) were diagnosed and treated. Postoperative voiding difficulties, dyspareunia, or pain were not observed. The operation with the trocarless system was found to be safe, easy to learn and implement, and have the potential for reducing intra- and postoperative complications, with very satisfactory functional and anatomical results.

Extended endonasal approach to the anterior skull base: endoscopic anatomic study

Objective To discuss the feasibility of using the extended endoscopic endonasal approach for exposing the anterior skull base,exploring surgical indications and preventing complications.Methods Endoscopic dissections were performed with the adjunct of neuronavigation using a rigid endoscope (Karl Storz) that was 4 mm in diameter,18 cm in length,and equipped with 0,30,and 45lenses.An extended endoscopic endonasal approach to the anterior skull base was made through two nostrils in all cases to measure the distance between the main anatomical landmarks and areas of exposure.Results A maximum lateral extension was obtained between the two medial orbital walls,separately at the base of crista galli (mean distance 34.1 ± 4.2 mm),and in the middle of the cribriform plate (mean distance 24.7 ± 3.1 mm).The distance between the bilateral anterior ethmoidal arteries was (26.8± 3.4) mm,and the distance between the bilateral posterior ethmoidal arteries was (24.3 ± 4.1) mm.In addition,the mean distance between the anterior and posterior ethmoidal arteries,at the level of lamina papyracea,was (17.9 ±2.7) mm.The area of the anterior skull base was (430.6 ±53.4) mm2 under the endoscopic view through this approach.Once the dura was opened,the recognizable structures were the olfactory nerves,the gyri recti of the frontal lobes,and the anterior interhemispheric fissure.Conclusion The extended endoscopic endonasal approach,guided by neuronavigation,could provide wider operative fields.Furthermore,it can be considered a minimally invasive technique to approach the anterior skull base.Adequate endoscopic skills,ample endoscopic anatomy,and reliable reconstruction techniques were required for the clinical application of this method. Key words: Endoscopy ; Endonasal approach; Anterior skull base

Anterior Approach to Cervical Spine

Review of surgical technique. To provide accounts of the authors' preferred methods for performing anterior cervical surgery with personal tips and pearls. Many have described the various anterior surgical approaches to the cervical spine, and in this review, we hope to describe our preferences, highlighted with some tips and pearls. Various accounts of the transoral, the anterolateral (Smith-Robinson), and the split manubrium approaches were reviewed and used as the basis of the review. Additional notes with regard to the authors' preferences were noted to provide further guidance. The descriptions were delineated from the most cephalad to the most caudal. The transoral, the anterolateral (Smith-Robinson), and the manubriotomy approaches were described. Each account starts with the basic preoperative considerations, then describes the incision and the main anatomical landmarks, and finally concludes with closure and main complications to monitor for. A brief description of the main pathologies that each approach may address is also provided. The 3 anterior approaches to the cervical spine are direct and elegant solutions to pathologies arising from the anterior column. They supplement the more commonly used posterior approaches, which provide stronger multilevel fixation, and thus provide an essential tool in the armamentarium of spine surgeons.

Endonasal endoscopic exposure of the internal carotid artery: An anatomical study

The aim of this work was to define the anatomical landmarks, limitations, and difficulties of obtaining internal carotid artery (ICA) exposure via endonasal endoscopic approaches (EEA). Cadaveric descriptive study. The ICA was dissected via EEA in 10 cadaveric specimens (20 sides) prepared with intravascular injections of colored silicone. We carried the ICA dissection from the cavernous to the distal parapharyngeal segments through a transpterygoid corridor. The transpterygoid approach provided adequate exposure of the lacerum and horizontal petrous ICA. Additional exposure of the ICA and the infrapetrous area required resection of the eustachian tube (ET) and the fibrocartilaginous tissue of the foramen lacerum after a medial maxillectomy and resection of the pterygoid plates. The main anatomical landmarks to the corresponding ICA segment include: the vidian nerve that points to the lacerum and horizontal segments, the mandibular nerve (V3) that heralds the petrous segment, the foramen ovale and the ET that signal toward the carotid canal, and the posterior trunk of the mandibular nerve (V3) and the ET that mark the parapharyngeal segment. EEAs provide access to the ICA from its cavernous to the distal parapharyngeal segments. A stepwise approach is critical to its exposure and control. Surgeons must be aware of its frequently tortuous three-dimensional course and the intimate relation of the vessel to the carotid canal and the cartilage of the foramen lacerum.

A practical approach to the lateral cutaneous nerve of the thigh: An anatomical study

Objectives To study the main anatomical landmarks related to the lateral cutaneous nerve of the thigh (LCN) in the infrainguinal region and to define reliable criteria for identifying the nerve during the surgery and electrophysiological study. Methods Bilateral dissections of 60 adult non-fixed cadavers were performed with measurements of the distance between the inferior border of the anterior superior iliac spine (ASIS) and the LCN (DAL) and the internal angle between the LCN and the inguinal ligament (IA). The number of nerves exiting the inguinal ligament, the position of the LCN relative to the ASIS and to inguinal ligament were observed and registered. A triangle was designed using the inguinal ligament, the ASIS and the direction of tendinous insertions of the tensor of fascia lata muscle as parameters and the nerves were tested according its localization inside the triangle in each dissection. Results In 80% of the dissections, the LCN passed under the inguinal ligament and was identified lateral to ASIS in only three dissections. A great variability was observed in the values of DAL and IA. The values of DAL ranged from 0 (immediately medial to ASIS) to 5 cm on either side with means of 1.31 and 1.22 cm on the right and left side, respectively. The values of IA ranged from 40° to 120°, with a mean of 66.08° on the right side and from 40° to 130° with a mean of 69.92° on the left side. No significant differences were identified between the two sides with respect to the relationship between the nerve and the inguinal ligament (Chi-square test, p = 0.83); DAL ( t test, p = 0.37) or IA ( t test, p = 0.15). A single nerve was found in 70.83% of the dissections. The nerve was found inside the triangle in 95% of the dissections. Conclusions Despite the symmetry found between the right and left sides, the values of the main anatomic parameters involved in the localization of the LCN presented a great degree of variability. Even so, dissection using the proposed anatomical triangle allows for the localization of the LCN in almost all cases.

Fetal MRI as a complement to US in the evaluation of cleft lip and palate

The aim of our study was to investigate the role of fetal magnetic resonance imaging (MRI) as a complement to ultrasound (US) in the evaluation of cleft lip and palate (CLP), whether isolated or in association with syndromic conditions. We enrolled 24 pregnant women (27 fetuses) (mean gestational age 23.7 weeks) with a level-two US diagnosis of cleft lip (CL) or CLP with or without associated central nervous system (CNS) or facial-bone anomalies. All individuals underwent a fetal MRI examination to study the facial skeleton, CNS and fetal body. For each fetus, the main anatomical facial landmarks and biometric parameters [anteroposterior diameter (APD), biparietal diameter (BPD), inferior facial angle (IFA), frontomaxillary angle (FMA), bi-orbital diameter (BOD), intraorbital diameter (IOD)] were measured. Twenty-five of 27 fetuses had a US diagnosis of CL or CLP. MRI confirmed the diagnosis in 16/25 fetuses and added information about the extent of the cleft and the degree of involvement of the anterior and posterior palate in 8/25 fetuses. MRI ruled out the diagnosis in 1/25 fetuses and identified an alteration of the parameters IFA, FMA and IOD in 6/24 fetuses. In the study of CLP fetal, MRI is able to define the degree of involvement of the posterior palate and the lateral extent of the cleft with higher diagnostic accuracy than US. Furthermore, MRI provides a complete study of the fetal head and biometric development of the facial bones, thus enabling early detection of potential syndromic conditions.

Anatomic Study of Middle Fossa Approach Landmarks Using an Image Guidance System

We sought to verify the relevance and reliability of the main temporal bone anatomic landmarks commonly used for the middle fossa approach and to test the use of digital technology to perform an accurate analysis of these landmarks. Ten fresh cadaveric temporal bones (5 heads) were analyzed by both computed tomographic imaging and dissection procedures, with the help of an image guidance system (DigiPointeur). Eight landmarks, which were selected for their wide citation in the otoneurosurgical literature, were studied. Of the 8 landmarks studied, we obtained results similar to previously published data for 2 (the distance between the temporal squama and the internal auditory meatus [IAM] fundus, and the distance between the top of the anterior semicircular canal [ASCC] arch and the IAM fundus), but divergent measurements for the other 6 (the distance between the temporal squama and the arcuate eminence; the distance between the top of the ASCC arch and the cochlear promontory; the IAM roof thickness; the angle formed by the ASCC arch plane orientation and the IAM axis; the angle formed by the head of the malleus, the geniculate ganglion, and the IAM fundus; and the correspondence between the arcuate eminence and the top of the ASCC arch). The use of an image guidance system allowed us to make sharp and precise measurements of the main anatomic landmarks used during a middle fossa approach. We found 6 measurements to be different from those reported in previously published data out of the 8 landmarks studied.

Anatomical Study of the Endonasal Endoscopic Approaches to the Skull Base

Introduction: Our work seeks to demonstrate the anatomical possibilities and limits of endonasal endoscopic approaches. Detailed knowledge of the anatomy of the rhinosinusal compartment and of the skull base is a prerequisite to practicing the surgical treatment of pathologies involving these regions. The anatomical dissection, performed with endoscopic technique, is an indispensable tool that allows a surgeon to acquire real anatomical knowledge, which is not mediated by schemes, and to obtain adequate skill and relative confidence with the surgical technique. The aim of this work was to focus on the main anatomical landmarks for and the risks of the surgical technique.

Échographie et anesthésie locorégionale

The use of ultrasound is the latest major evolution in regional anaesthesia. Review of available literature shows significant changes in clinical practice. Ultrasound guidance allows the visualization of anatomical variations or unsuspected intraneural injections, reduces the volume of local anaesthetic injections and confirms correct local anaesthetic distribution or catheter placement. No study has found a statistical difference in success rates and safety because all studies were underpowered. However, the ability to visualize an invasive procedure that has been performed blindly in the past is an undeniable progress in terms of safety. The necessity to be familiar with the machine and the learning curve can be repulsive. The aim of this article is to demystify ultrasound guidance by explaining the fundamentals of the clinical use of ultrasound. With the help of different chapters, the authors explain the different adjustments and possible artefacts and give easy solutions for the use of bedside ultrasound. Training is essential and can be performed on manikins or training phantom. For each region the main anatomical landmarks are explained. One must be familiar with several imaging techniques: short axis (transverse) or long axis (longitudinal) nerve imaging, in-plane or out-of-plane imaging and hydrolocalization. Viewing the needle's tip position during its progression remains the main safety endpoint. Therefore, electrical nerve stimulation and ultrasound guidance should be combined, especially for beginners, to confirm proximity to neural structures and to help in case of difficulty. Optimizing safety and clinical results must remain a key priority in regional anaesthesia. Finally, specific regulations concerning the transducers are described. Paediatric specificities are also mentioned.

Comparison of the Comformation of 20 International Level and the 20 Low Level Jumping Horses Using a 3‐D Video Morphometric Measurement Method

A new method of morphometric measurement has been developed (method presented as a poster at the 2002 EAVA congress). Its main originalities are (1) to use video (each horse is filmed while walking instead of being photographed at standing), (2) to be in 3‐D (4 digital cameras are used; they film the horse from its lateral side, and also from the front and rear), (3) not to require skin markers (which makes the recording procedure quicker). This method is presently applied in the context of the breeding program of the Selle Français (SF) horse, through two large sample studies. Before starting the analysis of the corresponding data, a preliminary study was performed in order to settle the analysis methodology and to select the most pertinent morphometric parameters to characterize the “model” (conformation) of sport horses. Twenty international level SF horses (jumping performance index (ISO) &gt;= 150, group A), and 20 low‐level (class D) jumping horses (group B) were compared using the 3‐D method. Out of the 400 morphometric parameters calculated for each horse, about 132 revealed significant differences (Student test, P &lt; 0,05) between the 2 groups; P was &lt; 0.001 for 26 of these parameters. The height of the main anatomical landmarks of the pelvic limb, acting as essential lever arms for propulsion muscles (ex: point of the hock (tuber calcanei), ischial tuber), and the height – absolute and relative (to the withers height) – of the croup, the length of the croup and thigh, the length of the fore cannon, the shortness of the forearm, and the relative shortness of the trunk, are all conformational traits that characterize group A compared with group B.

Biomechanical characteristics of adults walking in shallow water and on land

Although water environment has been employed for different physical activities, there is little available information regarding the biomechanical characteristics of walking in shallow water. In the present study, we investigated the kinematics, ground reaction forces (GRF), and electromyographic (EMG) activation patterns of eight selected muscles of adults walking in shallow water and on land. Ten healthy adults were videotaped while walking at self-selected comfortable speeds on land and in water (at the Xiphoid process level). In both conditions there was a force plate embedded in the middle of each walkway to register the GRF components. Reflective markers were placed over main anatomical landmarks and they were digitalized later to obtain stride characteristics and joint angle information. In general, walking in water was different to walking on land in many aspects and these differences were attributed to the drag force, the apparent body weight reduction, and the lower comfortable speed during walking in shallow water. The joint range of motions (ROM) were not different, the segment ROM, magnitudes of GRF components, impact force, and impulse were different between the two conditions. The present results will contribute to a better understanding of this activity in the context of training and rehabilitation.

Obituary: Professor A. Beller (1912–1996)

The improvement in the knowledge of the main anatomical landmarks permits an evolution in the safety of the surgical treatment and a conceptual development of the geometrical anatomicosurgical characteristics of the infratemporal fossa. This conceptual evolution determines surgical and oncological advantages : firstly, improved comprehension of the anatomico-surgical limits of the resection and secondly the safeguarding of the oncological en-bloc dissection. The lateral approach of the infratemporal fossa gives a wider exposure of the surgical field, a shorter depth of work, a good control over the vessels and the possibility of carry out a microsurgical transfer. The surgical approaches correspond to the topographical location and the biology of the neoplasm in cases with infratemporal fossa and inferior compartment location the lateral transfacial approach is indicated. In cases with involvement of the superior compartment a lateral transcraniofacial subtemporal approach is necessary in order to remove the skull base. In cases with a neoplastic invasion of the skull base where the dura mater is the anatomical plane free from disease it is necessary to utilize an intradural approach. In patients with a secondary spread into the inferior compartment from the maxilla a combined antero-lateral transfacial approach is indicated. Finally, an orbitomaxillary involvement with secondary spread in the upper compartment of the infratemporal fossa necessitates an antero-lateral transcraniofacial subtemporal subfrontal approach.

Infratemporal fossa surgery for malignant diseases.

The improvement in the knowledge of the main anatomical landmarks permits an evolution in the safety of the surgical treatment and a conceptual development of the geometrical anatomico-surgical characteristics of the infratemporal fossa. This conceptual evolution determines surgical and oncological advantages: firstly, improved comprehension of the anatomico-surgical limits of the resection and secondly the safeguarding of the oncological "en-bloc" dissection. The lateral approach of the infratemporal fossa gives a wider exposure of the surgical field, a shorter depth of work, a good control over the vessels and the possibility of carry out a microsurgical transfer. The surgical approaches correspond to the topographical location and the biology of the neoplasm in cases with infratemporal fossa and inferior compartment location the lateral transfacial approach is indicated. In cases with involvement of the superior compartment a lateral transcraniofacial subtemporal approach is necessary in order to remove the skull base. In cases with a neoplastic invasion of the skull base where the dura mater is the anatomical plane free from disease it is necessary to utilize an intradural approach. In patients with a secondary spread into the inferior compartment from the maxilla a combined antero-lateral transfacial approach is indicated. Finally, an orbitomaxillary involvement with secondary spread in the upper compartment of the infratemporal fossa necessitates an antero-lateral transcraniofacial subtemporal subfrontal approach.

A radiographic base line for demonstrating sinuses and facial bones in pediatric radiography.

For many years the radiographic and Reid's base lines have been used as the main anatomical landmarks for positioning various projections of the skull, sinuses, and facial bones. Both base lines maintain a constant relationship to the cranial vault which does not vary from infancy to adulthood. This is not true, however, in the relation of these base lines to the facial bones of the infant and child. We know that the ratio of the facial bones to the cranium changes as the infant grows. Therefore, the angle between the radiographic or Reid's base lines and each structure of the facial bones varies, making the base lines inaccurate with reference to projections of the facial bones and sinuses in pediatric radiology. An anatomic line which maintains a fixed relation to the facial bones throughout the period of growth was found in the acantho-meatal line, hereafter referred to as the “pediatric base line” (P.B.L.). The P.B.L. extends from the external auditory meatus to the anterior nasal spine. The movement ...