Key Anatomic Points Research Articles

Cranio-Orbital Approach and Decompression of the Optic Nerves: A 2-Stage, 4-by-4-Step Approach to Improve Vision in Sellar and Parasellar Lesions.

Despite advances in cranial base techniques, surgery of the sellar and parasellar regions remains challenging because of complex neurovascular relationships. Lesions within this region frequently present with progressive visual deterioration caused by distortion and compression of the optic chiasm and nerves. In addition to the direct mass effect from mechanical forces acting on the optic apparatus, these lesions alter blood supply and reduce vascular perfusion, prompting surgical treatment to remove the lesion, alleviate compression, and improve blood flow to the optic nerve. We sought to describe a 2-stage, 4-by-4-step approach, broken down and described as a "four-by-four" technique for optic apparatus decompression and a wide approach to different sellar and parasellar lesions. We describe the operative nuances and key anatomic points in the microsurgical removal of sellar and parasellar lesions. The technique is illustrated with examples of different cases with pre- and follow-up MRI imaging and a brief overview of visual outcomes. The described technique has been demonstrated in various lesions in 5 patients. Patients presented with bilateral visual loss in 4 (80.0%) cases and with unilateral visual loss in 1 (20.0%) case. Improvement in visual function was noted in all cases, confirmed with visual acuity and visual field testing. The transcranial approach ("from above") remains an important surgical option for patients with excellent exposure and visualization of the sellar and parasellar regions. It permits early access to the optic canal for careful microsurgical decompression and relaxation of the optic nerve to preserve and improve its microvascularization and ultimately vision. The authors augmented the 2-stage, 4-by-4-step technique of decompression with elaborate illustrations of diverse sellar and parasellar lesions to demonstrate the versatility of this approach.

Association between body condition score and abdominal fat assessed by ultrasound in Jersey cows.

Body condition score (BCS) is a subjective tool and the deposition of subcutaneous fat differs from the deposition of abdominal fat. The aim of this study was to evaluate by multivariate regression models and ultrasonography the amount of fat accumulated in different areas of the abdominal cavity in Jersey non-pregnant non-lactating cows and its association with their BCS. From a commercial farm, 21 non-pregnant non-lactating Jersey cows were selected at random. Cows were placed in a headlock line, and BCS was evaluated (scale 1-5 with a 0.25 unit increment) by the same assessor. Ultrasonographic evaluation was performed using a Sonosite machine in duplicate, considering key anatomical points of the body to predict total abdominal fat (AT), retroperitoneal fat (RT), omental fat (OT) and mesenteric fat (MT). A regression analysis for each abdominal fat depot and the BCS was run using SAS. Models from the lowest to the largest r2 are reported. The r2 for the models were MT r2=0.023; RT r2=0.1047; OT r2=0.323 and AT r2=0.369. Correlation between BCS and abdominal fat depots was positive, lower for mesenteric and retroperitoneal fat, but higher for omental and total abdominal fat. Cows were divided on the basis of the median of BCS distribution to high (≥3.5) and low (≤3.25). Those with high BCS had significantly larger amounts of fat in different anatomical areas of abdominal cavity than cows with low BCS. BCS has a low-to-moderate association with abdominal fat depots, but a high variability exists within each BCS punctuation, which supports the notion that fat accumulation patterns and metabolic turnover between abdominal and subcutaneous fat differ from each other.

Computer Vision for Assessing Surgical Movements in Neurosurgery.

Objective evaluation of microsurgical technique quality is vital for successful training in neurosurgery. This study aimed to assess the accuracy of automatically detecting a neurosurgeon's proper posture and hand positioning using computer vision. We employed the RTMPose neural network model to identify key anatomical points in the neurosurgeon's projection and calculated various angles formed by connecting these points. By utilizing machine learning on these angles, we were able to classify images of the surgeon's posture and hands into correct positions and various types of errors with an accuracy of at least 0.9. Computer vision enables successful detection and objective assessment of the neurosurgeon's posture and hand positions. The high accuracy of this detection can pave the way for a new training approach in neurosurgery.

Depth of the subcutaneous tissue in the nose: Application to filler injection.

The nasal region plays a pivotal role in both facial esthetics and functionality. The use of volumizing fillers has emerged as a potential means to enhance nasal appearance. Preliminary findings from cadaveric studies have highlighted potential risks associated with deeper needle injection, leading to cartilage damage and lateral migration of filler material. Understanding the subcutaneous tissue depth is crucial to prevent such complications and ensure safe filler placement guided by anatomical knowledge. This study aimed to employ ultrasonographic assessment to precisely measure the depth of soft tissue in the nasal area. Fifty-two participants without prior nasal surgery or filler injections underwent detailed ultrasonographic evaluation, focusing on seven key anatomical points: Glabellar, Sellion, Rhinion, between Rhinion and Pronasal, Pronasal, between Pronasal and Subnasal, and Subnasal. The ultrasonographic observation revealed varying depths of subcutaneous tissue across these points: Glabellar (4.11 ± 0.79), Sellion (5.21 ± 0.97), Rhinion (2.02 ± 0.74), Rhinion to Pronasal midpoint (6.45 ± 3.1), Pronasal (9.5 ± 2.2), between Pronasal and Subnasal (8.8 ± 0.8), and Subnasal (8.5 ± 0.5). The discussion underscores the significance of understanding subcutaneous tissue depth in guiding needle length and approach angles during filler injections. This knowledge aids in achieving effective filling while ensuring safe placement within the subcutaneous tissue.

Rapid Estimation of Contact Stresses in Imageless Total Knee Arthroplasty

Total knee arthroplasty (TKA) is a surgical technique to replace damaged knee joints with artificial implants. Recently, the imageless TKA has brought a revolutionary improvement to the accuracy of implant placement and ease of surgical process. Based on key anatomical points on the knee, the software guides the surgeon during the TKA procedure. However, the number of revision surgeries is increasing due to malalignment caused by registration error, resulting in imbalanced contact stresses that lead to failure of the TKA. Conventional stress analysis methods involve time-consuming and computationally demanding finite element analysis (FEA). In this work, a machine-learning-based approach estimates the contact pressure on the TKA implants. The machine learning regression model has been trained using FEA data. The optimal preprocessing technique was confirmed by the data without preprocessing, data divided by model size, and data divided by model size and optimal angle. Extreme gradient boosting, random forest, and extra trees regression models were trained to determine the optimal approach. The proposed method estimates the contact stress instantly within 10 percent of the maximum error. This has resulted in a significant reduction in computational costs. The efficiency and reliability of the proposed work have been validated against the published literature.

The growth of the mastoid volume in children with a cochlear implant

The aim of this study was to understand the mastoid volume development in children who undergo cochlear implantation surgery. Cochlear implant (CI) database of our clinic (Kuopio University Hospital) was reviewed for computed tomography (CT) images of CI patients (age under 12 years at the time of implantation) with a minimum time interval of twelve months between their pre- and postoperative CT. Eight patients (nine ears) were found eligible for inclusion. Three linear measurements were taken by using picture archiving and communication systems (PACS) software and the volume of the MACS was measured with Seg 3D software. The mastoid volume increased on average 817.5 mm3 between the pre- and the postoperative imaging time point. The linear distances measured between anatomical points like the round window (RW)- bony ear canal (BEC), the RW-sigmoid sinus (SS), the BEC-SS, and the mastoid tip (MT)-superior semicircular canal (SSC) increased significantly with the age of the patient at both the pre-op and post-op time points. The linear measurements between key anatomical points and mastoid volume showed a positive linear correlation. The correlation between linear measurement and volume were significant between the MT-SSC (r = 0.706, p = 0.002), RW-SS (r = 0.646, p = 0.005) and RW-BEC (r = 0.646, p = 0.005). Based on our findings from the CI implanted patients and comparing it with the previous literature findings from non-CI implanted patients, we could say that the CI surgery seem to have no effect on the development of mastoid volume in children.

Accuracy of a 3D temporal scanning system for gait analysis: Comparative with a marker-based photogrammetry system

BackgroundCombining the accuracy of marker-based stereophotogrammetry and the usability and comfort of markerless human movement analysis is a difficult challenge. 3D temporal scanners are a promising solution, since they provide moving meshes with thousands of vertices that can be used to analyze human movements. Research questionCan a 3D temporal scanner be used as a markerless system for gait analysis with the same accuracy as traditional, marker-based stereophotogrammetry systems? MethodsA comparative study was carried out using a 3D temporal scanner synchronized with a marker-based stereophotogrammetry system. Two gait cycles of twelve healthy adults were measured simultaneously, extracting the positions of key anatomical points from both systems, and using them to analyze the 3D kinematics of the pelvis, right hip and knee joints. Measurement differences of marker positions and joint angles were described by their root mean square. A t-test was performed to rule out instrumental errors, and an F-test to evaluate the amplifications of marker position errors in dynamic conditions. ResultsThe differences in 3D landmark positions were between 1.9 and 2.4 mm in the reference pose. Marker position errors were significantly increased during motion in the medial-lateral and vertical directions. The angle relative errors were between 3% and 43% of the range of motion, with the greatest difference being observed in hip axial rotation. SignificanceThe differences in the results obtained between the 3D temporal scanner and the marker-based system were smaller than the usual errors due to lack of accuracy in the manual positioning of markers on anatomical landmarks and to soft-tissue artefacts. That level of accuracy is greater than other markerless systems, and proves that such technology is a good alternative to traditional, marker-based motion capture.

Automatic annotation of cervical vertebrae in videofluoroscopy images via deep learning.

Judging swallowing kinematic impairments via videofluoroscopy represents the gold standard for the detection and evaluation of swallowing disorders. However, the efficiency and accuracy of such a biomechanical kinematic analysis vary significantly among human judges affected mainly by their training and experience. Here, we showed that a novel machine learning algorithm can with high accuracy automatically detect key anatomical points needed for a routine swallowing assessment in real-time. We trained a novel two-stage convolutional neural network to localize and measure the vertebral bodies using 1518 swallowing videofluoroscopies from 265 patients. Our network model yielded high accuracy as the mean distance between predicted points and annotations was 4.20 ± 5.54pixels. In comparison, human inter-rater error was 4.35 ± 3.12pixels. Furthermore, 93% of predicted points were less than five pixels from annotated pixels when tested on an independent dataset from 70 subjects. Our model offers more choices for speech language pathologists in their routine clinical swallowing assessments as it provides an efficient and accurate method for anatomic landmark localization in real-time, a task previously accomplished using an off-line time-sinking procedure.

Does Energy Drink Provokes Gait Modifications in Young Healthy Adults?

Energy drinks have become increasingly popular among young adults and athletes in the last few years. Despite their popularity, little research has substantiated the claims of the positive effects on physical performance of popular energy drinks. Most current research focuses on caffeine alone, but does not often look at how mixing it with other psychoactive substances might alter its effects. Purpose: This study aimed to determine the alterations of gait tasks after consumption of three popular energy drinks on young healthy adults. Methods: Fifteen women and five men were recruited, screened, and signed informed consent to participate in this study. All participants were healthy young adults with no apparent comorbidities that might have been impacted by the consumption of energy drinks. Motion analysis was conducted using Movement Lab TM sensors placed at key anatomical points. Subjects were asked for two bouts of gait tasks pre-energy drink consumption, and then repeat the same tasks after energy drink consumption. Results: There were no significant modifications in gait, however, observable trends were detected in postural gait parameters following the consumption of a Rockstar energy drink. Conclusion: We infer that the trends observed could be attributed to the specific key ingredients used in Rockstar and might have caused gait deviations post consumption. Further studies should focus on Rockstar alone and its specific key ingredients of caffeine, guarana, ginseng, and milk thistle to determine their influence on gait deviations.

Accuracy of New Deep Learning Model-Based Segmentation and Key-Point Multi-Detection Method for Ultrasonographic Developmental Dysplasia of the Hip (DDH) Screening

Hip joint ultrasonographic (US) imaging is the golden standard for developmental dysplasia of the hip (DDH) screening. However, the effectiveness of this technique is subject to interoperator and intraobserver variability. Thus, a multi-detection deep learning artificial intelligence (AI)-based computer-aided diagnosis (CAD) system was developed and evaluated. The deep learning model used a two-stage training process to segment the four key anatomical structures and extract their respective key points. In addition, the check angle of the ilium body balancing level was set to evaluate the system’s cognitive ability. Hence, only images with visible key anatomical points and a check angle within ±5° were used in the analysis. Of the original 921 images, 320 (34.7%) were deemed appropriate for screening by both the system and human observer. Moderate agreement (80.9%) was seen in the check angles of the appropriate group (Cohen’s κ = 0.525). Similarly, there was excellent agreement in the intraclass correlation coefficient (ICC) value between the measurers of the alpha angle (ICC = 0.764) and a good agreement in beta angle (ICC = 0.743). The developed system performed similarly to experienced medical experts; thus, it could further aid the effectiveness and speed of DDH diagnosis.

Traumatic injury of the petrous part of the temporal bone: Keys for reporting a complex diagnosis

Fractures of the petrous part of the temporal bone are a common lesion of the base of the skull; most of these fractures result from high-energy trauma. In patients with multiple trauma, these injuries can be detected on CT scans of the head and neck, where the direct and indirect signs are usually sufficient to establish the diagnosis. It is important to these fractures because the temporal bone has critical structures and the complexity of this region increases the risk of error unless special care is taken. This article reviews the key anatomical points, the systematisation of the imaging findings, and the classifications used for temporal bone fracture. We emphasise the usefulness of identifying and describing the findings in relation to important structures in this region, of looking for unseen fractures suspected through indirect signs, and of identifying anatomical structures that can simulate fractures. We point out that the classical classifications of these fractures are less useful, although they continue to be used for treatment decisions.

AIUM Practice Parameter for the Performance of Point-of-Care Ultrasound Examinations.

AIUM Practice Parameter for the Performance of Point-of-Care Ultrasound Examinations.

Patología traumática de peñascos, un diagnóstico complejo. Claves para el informe

Fractures of the petrous part of the temporal bone are a common lesion of the base of the skull; most of these fractures result from high-energy trauma. In patients with multiple trauma, these injuries can be detected on CT scans of the head and neck, where the direct and indirect signs are usually sufficient to establish the diagnosis. It is important to these fractures because the temporal bone has critical structures and the complexity of this region increases the risk of error unless special care is taken. This article reviews the key anatomical points, the systematization of the imaging findings, and the classifications used for temporal bone fracture. We emphasize the usefulness of identifying and describing the findings in relation to important structures in this region, of looking for unseen fractures suspected through indirect signs, and of identifying anatomical structures that can simulate fractures. We point out that the classical classifications of these fractures are less useful, although they continue to be used for treatment decisions.

Graph cut-based method for segmenting the left ventricle from MRI or echocardiographic images

In this paper, we present a fast and interactive graph cut method for 3D segmentation of the endocardial wall of the left ventricle (LV) adapted to work on two of the most widely used modalities: magnetic resonance imaging (MRI) and echocardiography. Our method accounts for the fundamentally different nature of both modalities: 3D echocardiographic images have a low contrast, a poor signal-to-noise ratio and frequent signal drop, while MR images are more detailed but also cluttered and contain highly anisotropic voxels. The main characteristic of our method is to work in a 3D Bezier coordinate system instead of the original Euclidean space. This comes with several advantages, including an implicit shape prior and a result guarantied not to have any holes in it. The proposed method is made of 4 steps. First, a 3D sampling of the LV cavity is made based on a Bezier coordinate system. This allows to warp the input 3D image to a Bezier space in which a plane corresponds to an anatomically plausible 3D Euclidean bullet shape. Second, a 3D graph is built and an energy term (which is based on the image gradient and a 3D probability map) is assigned to each edge of the graph, some of which being given an infinite energy to ensure the resulting 3D structure passes through key anatomical points. Third, a max-flow min-cut procedure is executed on the energy graph to delineate the endocardial surface. And fourth, the resulting surface is projected back to the Euclidean space where a post-processing convex hull algorithm is applied on every short axis slice to remove local concavities. Results obtained on two datasets reveal that our method takes between 2 and 5s to segment a 3D volume, it has better results overall than most state-of-the-art methods on the CETUS echocardiographic dataset and is statistically as good as a human operator on MR images.

Automatized Evaluation of the Left Ventricular Ejection Fraction from Echocardiographic Images Using Graph Cut

In this paper, we present a fast and interactive graph cut method for 3D segmentation of the endocardial wall of the left ventricle (LV) given 3D echocardiographic images. This is a challenging task due to the poor contrast and the low signal-to-noise ratio typical of echocardiographic images. The method is carried out in 3 steps. First, 3D sampling of the LV cavity is made in a spherical-cylindrical coordinate system. Then, a gradient-based energy term is assigned to each voxel, some of which being given an infinite energy to make sure the resulting volume passes through key anatomical points. Then, a graph-cut procedure provides delineation of the endocardial surface. Results obtained on 30 exams from the 2014 CETUS MICCAI challenge dataset reveal that our method takes between 5 and 10 seconds to segment a 3D volume with an overall mean surface distance lower than 2.3 mm and an ejection fraction error of less than 5% compared to a manual tracing by an expert.

Mitek Anchor–Augmented Static Facial Suspension

To evaluate the efficacy of the Mitek minianchor suture system as an adjunctive procedure for static facial suspension and assess its ability to improve functional and aesthetic outcomes in patients with complete facial paralyses. A retrospective review of 5 patients who underwent adjunctive static facial suspension with the Mitek GII minianchor suture system at a tertiary care academic center. A bone anchor in the maxilla connected to 2 suture arms was used. One suture arm elevated the oral commissure on the paralyzed side. The second suture arm adjusted for upper lip segment asymmetry and Cupid's bow deviation, or lateralized the external nasal valve. Outcome was evaluated by photodocumentation and clinical examination. There was an average of 76.9% improvement in vertical symmetry of the oral commissure (range, 43%-100%), an average of 65.0% improvement in horizontal deviation of the Cupid's bow (range, 50%-100%), and an average of 85.3% improvement in symmetry of upper lip segments (range, 67%-100%). All patients experienced improvement in oral-nasal competency. The Mitek minianchor suture system is a safe and effective adjunctive method to improve facial symmetry and oral-nasal competency in patients with facial paralyses. Its multivector design approximates the ideal positions of key anatomical points of the midface during static facial suspension surgery.

Mitek Anchor–Augmented Static Facial Suspension

To evaluate the efficacy of the Mitek minianchor suture system as an adjunctive procedure for static facial suspension and assess its ability to improve functional and aesthetic outcomes in patients with complete facial paralyses. A retrospective review of 5 patients who underwent adjunctive static facial suspension with the Mitek GII minianchor suture system at a tertiary care academic center. A bone anchor in the maxilla connected to 2 suture arms was used. One suture arm elevated the oral commissure on the paralyzed side. The second suture arm adjusted for upper lip segment asymmetry and Cupid's bow deviation, or lateralized the external nasal valve. Outcome was evaluated by photodocumentation and clinical examination. There was an average of 76.9% improvement in vertical symmetry of the oral commissure (range, 43%-100%), an average of 65.0% improvement in horizontal deviation of the Cupid's bow (range, 50%-100%), and an average of 85.3% improvement in symmetry of upper lip segments (range, 67%-100%). All patients experienced improvement in oral-nasal competency. The Mitek minianchor suture system is a safe and effective adjunctive method to improve facial symmetry and oral-nasal competency in patients with facial paralyses. Its multivector design approximates the ideal positions of key anatomical points of the midface during static facial suspension surgery.

The Craniocaudal Extension of Posterolateral Approaches and Their Combination

The aim of this study was to describe quantitatively the properties of the posterolateral approaches and their combination. Six silicone-injected cadaveric heads were dissected bilaterally. Quantitative data were generated with the Optotrak 3020 system (Northern Digital, Waterloo, Canada) and Surgiscope (Elekta Instruments, Inc., Atlanta, GA), including key anatomic points on the skull base and brainstem. All parameters were measured after the basic retrosigmoid craniectomy and then after combination with a basic far-lateral extension. The clinical results of 20 patients who underwent a combined retrosigmoid and far-lateral approach were reviewed. The change in accessibility to the lower clivus was greatest after the far-lateral extension (mean change, 43.62 +/- 10.98 mm2; P = .001). Accessibility to the constant landmarks, Meckel's cave, internal auditory meatus, and jugular foramen did not change significantly between the 2 approaches (P > .05). The greatest change in accessibility to soft tissue between the 2 approaches was to the lower brainstem (mean change, 33.88 +/- 5.25 mm2; P = .0001). Total removal was achieved in 75% of the cases. The average postoperative Glasgow Outcome Scale score of patients who underwent the combined retrosigmoid and far-lateral approach improved significantly, compared with the preoperative scores. The combination of the far-lateral and simple retrosigmoid approaches significantly increases the petroclival working area and access to the cranial nerves. However, risk of injury to neurovascular structures and time needed to extend the craniotomy must be weighed against the increased working area and angles of attack.

Moving toward the petroclival region: a model for quantitative and anatomical analysis of tumor shift

The authors quantitatively assessed the effects of balloon inflation as a model of tumor compression on the brainstem, cranial nerves, and clivus by measuring the working area, angle of attack, and brain shift associated with the retrosigmoid approach. Six silicone-injected cadaveric heads were dissected bilaterally via the retrosigmoid approach. Quantitative data were generated, including key anatomical points on the skull base and brainstem. All parameters were measured before and after inflation of a balloon catheter (inflation volume 4.8 ml, diameter 20 mm) intended to mimic tumor compression. Balloon inflation significantly shifted (p < 0.001) the brainstem and cranial nerve foramina (mean [+/- standard deviation] displacement of upper brainstem, 10.2 +/- 3.7 mm; trigeminal nerve exit, 6.99 +/- 2.38 mm; facial nerve exit, 9.52 +/- 4.13 mm; and lower brainstem, 13.63 +/- 8.45 mm). The area of exposure at the petroclivus was significantly greater with balloon inflation than without (change, 316.26 +/- 166.75 mm2; p < 0.0001). Before and after balloon inflation, there was no significant difference in the angles of attack at the origin of the trigeminal nerve (p > 0.5). This study adds an experimental component to the emerging field of quantitative neurosurgical anatomy. Balloon inflation can be used to model the effects of a mass lesion. The tumor simulation created "natural" retraction and an opening toward the upper clivus. The findings may be helpful in selecting a surgical approach to increase the working space for resection of certain extraaxial tumors.

Moving toward the petroclival region: a model for quantitative and anatomical analysis of tumor shift

Object The authors quantitatively assessed the effects of balloon inflation as a model of tumor compression on the brainstem, cranial nerves, and clivus by measuring the working area, angle of attack, and brain shift associated with the retrosigmoid approach. Methods Six silicone-injected cadaveric heads were dissected bilaterally via the retrosigmoid approach. Quantitative data were generated, including key anatomical points on the skull base and brainstem. All parameters were measured before and after inflation of a balloon catheter (inflation volume 4.8 ml, diameter 20 mm) intended to mimic tumor compression. Results Balloon inflation significantly shifted (p < 0.001) the brainstem and cranial nerve foramina (mean [± standard deviation] displacement of upper brainstem, 10.2 ± 3.7 mm; trigeminal nerve exit, 6.99 ± 2.38 mm; facial nerve exit, 9.52 ± 4.13 mm; and lower brainstem, 13.63 ± 8.45 mm). The area of exposure at the petroclivus was significantly greater with balloon inflation than without (change, 316.26 ± 166.75 mm2; p < 0.0001). Before and after balloon inflation, there was no significant difference in the angles of attack at the origin of the trigeminal nerve (p > 0.5). Conclusions This study adds an experimental component to the emerging field of quantitative neurosurgical anatomy. Balloon inflation can be used to model the effects of a mass lesion. The tumor simulation created “natural” retraction and an opening toward the upper clivus. The findings may be helpful in selecting a surgical approach to increase the working space for resection of certain extraaxial tumors.