Reliable Anatomical Landmarks Research Articles

Conventional Method Of Dissection Versus Identification Of Rouviere’s Sulcus And Cystic Lymph Node As Safety Landmarks In Laparoscopic Cholecystectomy: A Comparative Study.

Background: Laparoscopic Cholecystectomy (LC) is the Gold Standard procedure for symptomatic gallstones. With the development of laparoscopic procedure, surgical interest in the Rouviere’s sulcus and cystic lymph node in relation to the right portal pedicle and prevention of bile duct injury has increased recently. This prospective study aimed at safety landmarks for avoiding Bile Duct Injuries during surgery and reducing the number of intraoperative and postoperative complications in laparoscopic cholecystectomy. The aim of the study is to compare the frequency of bile duct injury in conventional method of dissection versus the frequency of bile duct injury by delineating rouviere’s sulcus and cystic lymph node as safety landmark in laparoscopic cholecystectomy. Material and Method: A comparative study was conducted on 60 patients of cholelithiasis who underwent laparoscopic cholecystectomy at our institution in two-year period. All patients were evaluated in terms of clinical, biochemical, haematological and ultrasonographic parameters and randomised in two groups. Patients were allocated group A and B depending upon Ticket picked by them. Group A patient: Rouviere’s sulcus and cystic lymph node was identified intraoperatively and an imaginary line (R4U) that passed from the sulcus across the base of segment 4 to the umbilical fissure drawn and cystic line is an imaginary line running through cystic lymph node and parallel to hepatoduodenal ligament was drawn and dissection superolateral to intersection of these lines along with achievement of CVS. Group B patients: Underwent conventional method of dissection (calot’s Triangle dissection with critical view of safety achievement). Patients were followed up after 7 days and assessment was done. Conclusion : the study concluded that before commencement of calot’s triangle dissection identification of Rouviere's sulcus [RS] and cystic lymph node of lund is an extra biliary, easily accessible and reliable anatomical land mark from where we can draw two imaginary line [R4U and cystic line] and dissection start above and lateral to intersection of these line and no injury was observed and one bile duct injury was noted during convention method of dissection. So it can help us as an additional safe reference point to avoid bile duct injury and dissection in safe area close to gall bladder in laparoscopic cholecystectomy.

Can surface landmarks help us identify the gibson interval during surgical hip dislocation: a study of 617 hips

IntroductionThe Gibson approach, used in hip-preserving surgery, is intermuscular and develops the space anteriorly to the gluteus maximus. Reliable anatomical landmarks for the development of this interval do not exist, but the interval is marked by perforating vessels (PV) of the inferior gluteal artery. The aim of this study was to provide reference values for the relationship between palpable anatomical landmarks on the femur/pelvis and the anterior border of the gluteus maximus using CT scans of the proximal femur.Materials and methodsSingle center retrospective study of 617 hips who underwent a CT-scan of the pelvis/femur. We defined 5 anatomical markers on the pelvis and proximal femur and measured the distance of the anterior border of the gluteus maximus in relation to the marker, which was either anterior or posterior. The amount PV’s and it’s location relative to the innominate tubercle were measured in the coronal plane. For each landmark we compared these subgroups: male vs female, age < 40 vs ≥ 40, categorical age (< 20; 20–40; 40–60; > 60), and categorical femoral torsion (< 10°; 10°–25°; 25°–35°; > 35°).ResultsMean location of the parameters A-E was at − 8.1 cm, 1.1 cm, 1.8 cm, 1.3 cm and 0.4 cm. Parameters B, C, and D were more posterior in the age ≥ 40 group. Parameters A–E were significantly more posterior in the age > 60 group. Parameters A and E were significantly more anterior in females than in males. 50% of the PV are found between 5 and 9 cm proximal to the innominate tubercle. No statistically significant differences were noted in the location of any of the perforating vessels in the different subgroups.ConclusionThe Gibson interval is located more anteriorly in female patients and patients under 40 years of age. It is located more posteriorly in patients over 60 years of age. In addition, the interval moves anteriorly with increasing femoral torsion, most notably in patients with very high femoral torsion (> 35°).

Characterizing the Rotational Profile of the Distal Femur: A Roadmap for Distal Femoral Replacement Surgery.

Standard references for determining rotational alignment are often unavailable when performing distal femoral replacement (DFR) surgery. This study aimed to describe the rotational profile of the distal femoral osteology at common resection levels. Adults with CT scans of the bilateral legs were included. Exclusion criteria included fractures, congenital deformity, prior arthroplasty, or inadequate imaging. Referencing the transepicondylar axis, angles were measured in the axial plane using the following reference lines: anterior condylar axis or anterior femoral cortex axis (AFCA), posterior condylar axis or posterior femoral cortex axis (PFCA), lateral projection of the linea aspera (LAA), and Whiteside line (WL). These rotational measurements were assessed at 3, 5, 7, and 9 cm proximal of the joint line. External and internal rotation were denoted as positive and negative, respectively. Fifty-one patients (102 femora) were included (mean age: 62.6 ± 13.4 years; mean body mass index: 26.0 ± 6.7 kg/m2). Proximally, the anterior condylar axis/anterior femoral cortex axis became increasingly internally rotated (3-cm: -13.1 ± 3.5°, 9-cm: -21.2 ± 6.6°), whereas the posterior condylar axis/PFCA became increasingly externally rotated (3-cm: -6.7 ± 2.3°, 9-cm: 9.6 ± 6.1°). WL remained nearly perpendicular (3-cm: 88.8 ± 2.3°, 5-cm: 89.8 ± 3.7°) but was not reliably measured beyond 5 cm. The LAA was measurable proximal to 5 cm from the joint line and was internally rotated (5-cm: -58.5 ± 14.3°, 9-cm: -45.6 ± 13.4°). Distally, WL is a reliable anatomic landmark for femoral implant rotation. At more proximal resection levels, the posterior cortex may be a valuable landmark as referencing the linea aspera may lead to gross internal rotation of the femoral implant.

Revisit to Endolymphatic Duct Identification Using Middle Cranial Fossa Dural Plate: A Novel Technique.

Surgical treatments for Ménière's disease differ in efficacy. Endolymphatic duct blockage (EDB) is favored for its minimal risk and ability to preserve hearing. One of the main challenges in the technique is the difficulty in accurately identifying the endolymphatic duct (ED). The aim of the study is to see the feasibility of identifying the ED opening using a middle cranial fossa (MCF) dural plate as a reference point in a wet temporal bone and to measure the angle between the ED opening and the MCFdural plate which in the future can simplify the procedure ofED blockage. This prospective observational study, conducted from February to April 2024 at R L Jalappa Hospital, involved dissecting 20 wet temporal bones. A complete cortical mastoidectomy exposed the MCF dural plate, semicircular canals, sigmoid sinus, and sinodural angle. Using Donaldsonline ES, through blind controlled drilling the operculum of the vestibular aqueduct was identified. The angle between the ED opening and the MCF dural plate was measured using GNU Image Manipulation Program (GIMP) software (Free Software Foundation Ltd., Boston, MA, USA). A tangential line from the MCF dural plate to the ED opening was drawn using the same software and the line was named the "GauthamaPrasads" (GP) line. The study documented angles between the ED opening and the MCF dural plate, which ranged from 36.00° to 45.99° (mean angles from 20 temporal bones provided). The angle of 36.00° to 45.99° between the MCF dural plate and ED was consistently observed, thus proving that the MCF dural plate isa reliable anatomical landmark for surgeons for identification of ED. Accurate identification of the ED was feasible using this new anatomical landmark. These findings provide valuable anatomical insights that can aid in more efficient and accurate surgical interventions involving the ED.

Evaluating proximal ulnar morphology in relation to the humeral flexion-extension axis

AimThe study aimed to evaluate the 3D relationship between the plane of the posterior surface of the olecranon, a newly defined plane through the ridge of the greater sigmoid notch, and the ulno-humeral flexion-extension axis (FE-axis), respectively. Methods24 healthy left elbows were CT-scanned and 3D segmented. First, a Cartesian ulnar coordinate system (UCS) was determined. Next, several anatomical landmarks were identified. The UCS and landmarks were assessed for repeatability and reproducibility. The orientation of the posterior surface and the plane through the greater sigmoid notch was evaluated relative to the anatomical FE-axis. ResultsBoth the UCS and the landmarks were considered repeatable and reproducible. In the axial plane, the mean angle between the posterior surface and the FE-axis was 3° (SD: ± 5 °, 95%CI: [-6°;12°]) external rotation. The mean axial angle between the greater sigmoid notch and the FE-axis was 88° (SD: ± 3°, 95%CI: [83°; 94°]) external rotation. ConclusionsThis study concludes that the angulation between the posterior plane surface and the FE-axis is highly variable (95% CI range: 18°). The plane through the ridge of the greater sigmoid notch of a healthy proximal ulna could provide a more reliable anatomical landmark to estimate the position of the elbow FE-axis compared to the posterior surface (95% CI range: 11°).

Osteophyte of the first costochondral joint is a reliable landmark to facilitate standardized robotic left internal mammary artery harvesting

ObjectiveRobotic left internal mammary artery (LIMA) harvesting can present various challenges for novice surgeons. This study aimed to investigate whether the osteophyte of the first costochondral joint (OFCCJ) could serve as an anatomical landmark for robotic LIMA harvesting and to explore the optimal standardized process. MethodsThe concept of “LIMA isthmus” was described on the basis of relatively fixed anatomical relationship between LIMA and OFCCJ, and the height of OFCCJ and its distance to LIMA were defined. The presence and features of OFCCJ were analyzed in 514 hospitalized patients with or without coronary artery diseases (CAD or non-CAD). The value of “LIMA isthmus”-based robotic harvesting strategy was further assessed for beginners during the learning curve phase. ResultsThe OFCCJs were found to be very common in the adult population. The prevalence of OFCCJ in patients with CAD was significantly greater than in patients without CAD (73.16% vs 60.33%, P < .01). However, there were no significant difference between the CAD and the non-CAD group in the height of the OFCCJ or the distance between the OFCCJ and the LIMA (15.54 ± 4.99 mm vs 16.55 ± 4.70 mm, P = .06; 12.66 ± 4.19 mm vs 12.45 ± 6.87 mm, P = .72). During the learning curve phase, the time to identify LIMA and the time for LIMA harvesting using “LIMA isthmus”-based strategy were significantly shorter than those with conventional approach (89.00 ± 31.07 seconds vs 1087 ± 436.1 seconds, P = .035; 86.80 ± 4.74 minutes vs 110.5 ± 11.72 minutes, P = .013). The inadvertent bleeding events with “LIMA isthmus”-based graft harvesting were much fewer (1.00 ± 0.19 vs 3.44 ± 0.34, P < .001), although there was no difference between 2 beginners in postoperative chest drainage, LIMA injury events, or conversion to a median sternotomy incision. ConclusionsOFCCJ could serve as a reliable anatomical landmark to guide robotic LIMA harvesting. “LIMA isthmus”-based standardized robotic LIMA harvesting could significantly reduce the time to determine LIMA and the time for graft harvesting process, and minimize the risk of inadvertent bleeding events. This could be particularly beneficial for novice surgeons during the initial learning curve phase of this procedure.

An Easy Way of Identification and Protection of the Hypoglossal Nerve during Neck Dissection for Head and Neck Cancer

Understanding the anatomical relationship between the Hypoglossal Nerve (HN) and the Facial Vein (FV) is crucial during neck dissections for head and neck cancer. The consistent placement of the HN beneath the FV provides a reliable anatomical landmark, aiding in the preservation of nerve function and reducing surgical complications. This paper reviews the anatomical pathway of the HN, its clinical implications, and surgical observations from 87 cases. Techniques for protecting the HN during neck dissection are also discussed, emphasizing the importance of precise surgical planning to avoid postoperative complications.

Enhanced Understanding of Facial Nerve Anatomy and Arborization in the Indian Population: Implications for Surgical Procedures.

The anatomy and arborization patterns of the extraparotid facial nerve show considerable variation among different populations, impacting surgical approaches in plastic, head and neck, and ENT surgeries. This study focuses on the Indian population to provide a detailed understanding of these variations, specifically highlighting the Davis type IV arborization pattern's prevalence and its clinical relevance. We conducted a comprehensive dissection of 16 formalin-preserved Indian cadaveric hemifaces. The study meticulously mapped the facial nerve trunk (FNT), its furcation points, and branches. Key anatomical landmarks for locating these nerve structures were identified, including the tip of the mastoid process, the angle of the mandible, and a novel line between the lateral palpebral fissure and otobasion superioris. The most common arborization pattern observed was Davis type IV (31.3%). The study provided precise measurements for locating the FNT and its branches, using identifiable landmarks. These findings facilitate more accurate surgical planning, crucial for procedures involving nerve repair or grafting. This research offers vital insights into the facial nerve anatomy specific to the Indian population, with significant implications for surgical precision and patient outcomes. By establishing reliable anatomical landmarks and elucidating the predominant arborization pattern, the study enhances the understanding of facial nerve behavior during surgical interventions, particularly in the context of facial paralysis treatment and reconstructive surgeries. Due to the small sample size, however, this study only acts as a pilot for further research.

Carotid Plexus Sympathetic Nerves as a Landmark for the Abducens Nerve Within the Cavernous Sinus During Endoscopic Endonasal Surgery: Cadaveric Anatomic Study and Surgical Consideration.

The abducens nerve (CN VI) is vulnerable to injury during endoscopic endonasal transcavernous surgery. In this study, the authors aimed to develop the surgical anatomic landmark and explore the relationship between the sympathetic nerves (SNs) around the internal carotid artery (ICA) and CN VI within the cavernous sinus (CS). The relationship and patterns between the SNs and CN VI were investigated in 15 cadaveric specimens. The intraoperative examples of anatomic landmark were presented. There were SNs around the ICA running into the CN VI, classified into ascending SNs and accessory sympathetic branches. The ascending SNs were divided into 3 types: (1) Type I had a single ascending SN. There were 2 subtypes of Type I (Type IA [17/30, 56.7%] was defined as a single ascending branch that ran into the CN VI, and Type IB [4/30, 13.3%] was defined as a single ascending branch with a terminal bifurcation before merging into the CN VI or lateral CS wall), (2) Type II (7/30, 23.3%) was defined as 2 ascending branches that ran into the CN VI and the lateral CS wall, and (3) Type III (2/30, 6.7%) was defined as 3 ascending branches that ran into the CN VIs and the lateral wall of the CS. The accessory branches of the SNs were defined by sympathetic branches from the posterior genu or horizontal ICA and found in 6/30 sides (20%). The authors propose a classification of the relationship between paraclival ICA SNs and the CN VI within the CS, as approached during endoscopic endonasal surgery. The consistent relationship of the ascending SN and CN VI within the CS provides a reliable anatomic landmark during the endonasal approach to the CS.

Connectivity defines the distinctive anatomy and function of the hand-knob area.

Control of the hand muscles during fine digit movements requires a high level of sensorimotor integration, which relies on a complex network of cortical and subcortical hubs. The components of this network have been extensively studied in human and non-human primates, but discrepancies in the findings obtained from different mapping approaches are difficult to interpret. In this study, we defined the cortical and connectional components of the hand motor network in the same cohort of 20 healthy adults and 3 neurosurgical patients. We used multimodal structural magnetic resonance imaging (including T1-weighted imaging and diffusion tractography), as well as functional magnetic resonance imaging and navigated transcranial magnetic stimulation (nTMS). The motor map obtained from nTMS compared favourably with the one obtained from functional magnetic resonance imaging, both of which overlapped well within the 'hand-knob' region of the precentral gyrus and in an adjacent region of the postcentral gyrus. nTMS stimulation of the precentral and postcentral gyri led to motor-evoked potentials in the hand muscles in all participants, with more responses recorded from precentral stimulations. We also observed that precentral stimulations tended to produce motor-evoked potentials with shorter latencies and higher amplitudes than postcentral stimulations. Tractography showed that the region of maximum overlap between terminations of precentral-postcentral U-shaped association fibres and somatosensory projection tracts colocalizes with the functional motor maps. The relationships between the functional maps, and between them and the tract terminations, were replicated in the patient cohort. Three main conclusions can be drawn from our study. First, the hand-knob region is a reliable anatomical landmark for the functional localization of fine digit movements. Second, its distinctive shape is determined by the convergence of highly myelinated long projection fibres and short U-fibres. Third, the unique role of the hand-knob area is explained by its direct action on the spinal motoneurons and the access to high-order somatosensory information for the online control of fine movements. This network is more developed in the hand region compared to other body parts of the homunculus motor strip, and it may represent an important target for enhancing motor learning during early development.

A novel intraoperative acetabular reaming center locating method in total hip arthroplasty for Crowe type IV developmental dysplasia of the hip: a retrospective cohort study.

Although the principles of hip reconstruction are consistent, due to lack of reliable anatomical landmarks, how to decide the acetabular cup reaming centre intraoperatively in Crowe IV patients with developmental dysplasia of the hip (DDH) remains unclear. This study aims to address this question. Fifty-eight Crowe IV patients were enrolled from 2017 to 2019. By examining our previous clinical data, we analyzed the anatomical morphology of Crowe IV acetabulum and proposed a method of locating intraoperative reaming centering for implantation of a standard-sized acetabular cup, which is the upper two thirds of the posterior border of the true acetabulum. All patients included in this study were reamed according to this method. The average postoperative follow-up was 4.1years (3-5years). The position of the centre of rotation (COR), cup coverage (CC), and optimal range of joint motion (ROM) were examined by 3D computer simulation measurement. Postoperative complications and hip Harris score were collected and analyzed. The morphology of the type IV DDH true acetabulum was mostly triangular. The intraoperative reaming centre were centered on the upper two thirds of the posterior border of the true acetabulum. The postoperative 3D CC was 80.20% ± 7.63% (64.68-90.24%, 44-48-mm cup size). The patients' mean Harris score improved from 39.7 ± 20.4 preoperatively to 91.5 ± 8.12 at the last follow-up. Our study demonstrated that satisfactory CC and clinical results could be achieved by implanting a standard-sized cup with the reaming centre on the upper twothirds of the posterior border of the true acetabulum.

The new morphologic classification of the hand motor cortex with magnetic resonance imaging in glioma patients

PurposeThe hand motor cortex (HMC) is a reliable anatomical landmark for identifying the precentral gyrus. The current study aimed to investigate the morphology of HMC on axial MRI of glioma patients, propose a new morphological classification of HMC and analyze the effect of tumors on the morphology of HMC. MethodsA retrospective study of 276 adult right-handed glioma patients was conducted. The morphology of HMC was assessed using T2 axial images. Subsequently, the distribution of morphological subtypes was compared between the bilateral hemispheres and the tumor-affected and healthy hemispheres. Finally, the influence of tumor pathology on the morphology of HMC was investigated. ResultsA new morphological classification of HMC with four subtypes (Ω, ε, Ω-ε and ε-Ω) was proposed. No significant difference was identified in the distribution of morphological subtypes between the bilateral hemispheres (p = 0.0901, Chi-square test), or between the tumor-affected and healthy hemispheres (p = 0.3507, Chi-square test), and the morphology of HMC between the bilateral hemispheres were consistent (p < 0.0001, Kappa test). In addition, a significant difference was identified in the distribution of morphological subtypes between astrocytic and oligodendroglial tumors (p = 0.0135, Chi-square test). ConclusionIn the current study, we proposed a new morphological classification of HMC, and found that tumor could affect the morphology of HMC in glioma patients. The results can help our clinical practice, enabling us to further understand the spatial structure of the cerebral hemispheres.

Evaluation of the Anatomical Reference Point in Posterior Minimally Invasive Atlantoaxial Spine Surgery: A Cadaveric Anatomical Study.

Minimally invasive atlantoaxial surgery offers the benefits of reduced trauma and quicker recovery. Previous studies have focused on feasibility and technical aspects, but the lack of comprehensive safety information has limited its availability and widespread use. This study proposes to define the feasibility and range of surgical safety using the intersection of the greater occipital nerve and the inferior border of the inferior cephalic oblique as a reference point. Dissection was performed on 10 fresh cadavers to define the anatomical reference point as the intersection of the greater occipital nerve and the inferior border of the inferior cephalic oblique muscle. The study aimed to analyze the safety range of minimally invasive atlantoaxial fusion surgery by measuring the distance between the anatomical reference point and the transverse foramen of the axis, the distance between the anatomical reference point and the superior border of the posterior arch of the atlas, and the distance between the anatomical reference point and the spinal canal. Measurements were compared using Student's t test. The point where the occipital greater nerve intersects with the inferior border of the inferior cephalic oblique muscle was defined as the anatomical marker for minimally invasive posterior atlantoaxial surgery. The distance between this anatomical marker and the transverse foramen of the axis was measured to be 9.32 ± 2.04 mm. Additionally, the distance to the superior border of the posterior arch of the atlas was found to be 21.29 ± 1.93 mm, and the distance to the spinal canal was measured to be 11.53 ± 2.18 mm. These measurement results can aid surgeons in protecting the vertebral artery and dura mater during minimally invasive posterior atlantoaxial surgery. The intersection of the greater occipital nerve with the inferior border of the inferior cephalic oblique muscle is a safe and reliable anatomical landmark in minimally invasive posterior atlantoaxial surgery.

The accuracy and feasibility study of freehand pedicle screw insertion for subaxial cervical spine assisted with safe core-referred technique

Objectives: To construct the "safe core" of the pedicle screw trajectory using CT imaging data of the subaxial cervical spine in adults, and to assess the accuracy and feasibility of the pedicle screw insertion assisted with the "safe core-referred technique" for subaxial cervical spine with a cadaver specimen study. Methods: This is an experimental study. From January 2015 to March 2020,60 adults' CT images data of the cervical spine were collected from the database of the First Affiliated Hospital of Gannan Medical University,and were imported into Mimics 20.0 software. Virtual cervical pedicle trajectory and safe core were constructed according to the self-designed "virtual construction method of pedicle in the subaxial cervical spine". The success rate of the construction and the spatial position data of the virtual safe core of was recorded,including the distance between the safe core and the tangent line of the upper and lower outer edge of Luschka's joint on coronal plane,and the distance between the safe core and the posterior edge of the vertebral body on sagittal plane.The 3.5 mm column was used to simulate the pedicle screw placement,using the safe core as the only hub in pedicle screw trajectory.The length of the anterior pedicle screw trajectory,the interval of the abductive angle of the pedicle screw in axial plane, and the projection area of the entry area on periapical radiograph was calculated.In addition,8 adult cervical cadaver specimens were collected for the pedicle screw insertion experiment.The left side group used the "safe core-referred technique" for pedicle screw insertion,while the right side group used the Abumi method for pedicle screw insertion.The accuracy of pedicle screw placement was verified by CT scan.The difference between the accuracy of subjective judgment based on X-ray monitoring of operator and the actual accuracy of pedicle screw insertion verified by CT scan was compared between the two groups.The chi-square test was used to compare the intergroup data. Results: The total success rate of the virtual construction method for the safe core of the subaxial cervical spine was 97.0% (291/300); The distance between the safe core and the tangent line of the upper and lower outer edge of Luschka's joint on coronal plane was (M(IQR)) 0.91 (0.98) mm (range: 0 to 1.85 mm);The distance between the safe core and the posterior wall on the sagittal plane of the vertebral body was (2.01±0.86) mm (range: 0.67 to 3.53 mm). The distance (anterior pedicle screw trajectory) from the posterior cortex to the central point of the safe core was (11.58±1.00)mm (range: 8.27 to 14.93 mm).The projection area of the entry point on the coronal plane was (36.18±11.67) mm2 (range: 13.38 to 83.11 mm2). Pedicle screw insertion experiment in cervical cadaver specimen showed the rate of intraoperative correction of the pedicle screw trajectory was 7.5% (3/40) in the experimental group and 12.5% (5/40) in the control group (χ2=0.139,P=0.709). The operator 's correct rate of subjective judgment on CT in the stage of pedicle screw trajectory preparation was 100% (40/40) in the experimental group and 82.5% (33/40) in the control group, the difference was statistically significant (χ2=5.638,P=0.018). The actual correct rate of CT verification in the stage of pedicle screw insertion was 100% (40/40) in the experimental group and 90.0% (36/40) in the control group, the difference was statistically significant (χ2=2.368,P=0.124); The operator 's correct rate of subjective judgment in the stage of pedicle screw insertion completion was 100% (83/83) in the experimental group and 92.9% (79/85) in the control group (χ2=4.199,P=0.040). Conclusions: The virtual safe-core of subaxial cervical spine can be use as a reliable anatomical fluoroscopy landmark for freehand pedicle screw insertion."Safe core-referred technique" can improve the accuracy rate of the operator's subjective judgment on the intraoperative fluoroscopy monitoring,and hence improve the accuracy of freehand pedicle screw insertion technology for subaxial cervical spine. And it still needs to be further verified in clinical practice.

TO CORRELATE THE RELATIONSHIP OF THE DISTANCE BETWEEN LINGUAL FRENAL ATTACHMENT AND MANDIBULAR INCISAL EDGE POSITION AS AN AID IN ESTABLISHING MANDIBULAR OCCLUSAL PLANE: A CROSS-SECTIONAL SURVEY

Background: The determination of vertical dimension, aesthetics, phonetics and incisal guidance, depends on the placement of anterior teeth. Fewer studies are present for mandibular anterior teeth setting. Therefore this study aims at determining the correlation of distance between lingual frenal attachment and mandibular incisal edge position in dentulous subjects as an aid in establishing mandibular occlusal plane in edentulous patients. Methodology: 318 subjects (161 males and 157 females) under the age group of 18 to 30 years, who met the requisite criteria were seleceted. A mandibular cast was obtained from irreversible hydrocolloid impression in stock trays for each subject. The distance between the incisal edge of lower central incisor and anterior attachment of the lingual frenum was measured using digital vernier caliper. Result:It was observed that the distance between anterosuperior attachment of lingual frenumand mesioincisal edge of mandibular central incisor (CI) in female subjects was 12.19, with mean standard deviation (±SD) of 1.34. and 15.91 with mean standard deviation (±SD) 1.32 in male subjects respectively. Conclusion:Thus, the anterior attachment of lingual frenum is a reliable anatomic landmark and shall aid in setting the mandibular central incisors in a more natural position.

Anteromedial Petrous (Gardner's) Triangle: Surgical Anatomy and Relevance for Endoscopic Endonasal Approach to the Petrous Apex and Petroclival Region.

Triangular corridors have been used as reliable surgical entry points for open transcranial approaches to the petrous apex (PA) and petroclival region (PCR). The endoscopic endonasal approaches have grown rapidly in the last decade, and the indications have advanced. The knowledge of accurate and reliable anatomic landmarks through endoscopic endonasal route is essential and remain to be established. The purpose of this study was to describe the feasibility and surgical exposure of the anteromedial petrous (Gardner's) triangle as a novel corridor to the PA and PCR. Five anatomic specimens were dissected. The PA and PCR were accessed through endoscopic endonasal approaches and contralateral transmaxillary approach. The limits of the anteromedial petrous (Gardner's) triangle were identified and dissected and associated measurements performed. The dissection was divided into 6 steps. The limits of the anteromedial petrous (Gardner's) triangle were identified and defined by the paraclival internal carotid artery anterolaterally, the abducens nerve posteromedially, and the petroclival synchondrosis inferiorly. Three lines were established following the limits of the triangle. The mean distance of the anterolateral limit was 10.03 mm (SD = 0.94), of the posteromedial limit was 20.06 mm (SD = 2.90), and of the inferior limit was 17.99 mm (SD = 2.99). The mean area was 87.56 mm 2 (SD = 20.06). The 3 anatomic landmarks with a critical role to safely define the triangle were the pterygosphenoidal fissure, the petrosal process of the sphenoid bone, and the petroclival synchondrosis. The anteromedial (Gardner's) triangle is a well-defined bone corridor which provides access to the entire petrous bone and petroclival junction through endoscopic endonasal route. Regardless of the anatomic variations or tumor location, the landmarks of the abducens nerve, paraclival internal carotid artery, and petroclival synchondrosis are key for understanding lateral access to tumors extending from the clivus.

Volumetric analysis of artifacts from fiducial markers under cone beam computed tomography

Computer aided implant surgery has been widely adopted in modern implant dentistry. However, absence of reliable anatomic landmarks for superimposing digital data sets for patients with terminal dentition or complete edentulism remained challenging. Utilization of additional fiducial markers intraorally as the reference points for the improvement of accuracy became crucial in implant digital workflow. Nevertheless, the choice of the material for fiducial markers should present the least radiographic artifacts under cone beam computed tomography (CBCT) for better accuracy. The aim of this invitro study was to investigate the volume of radiographic artifacts generated through different materials under the image of CBCT. Fifteen dental materials were selected and configured into cubic shape. All the materials were scanned initially with the laboratory scanner as the control groups. The samples were scanned by CBCT machine as test groups and the volume of artifact generated under CBCT images were compared and analyzed using 3D modeling software. Eleven out of fifteen materials could be recognized under CBCT images. Volumetric analysis reported that statistically significant differences among the materials could be noted, and the flowable composite resin presented the least volumetric difference. Lithium disilicate glass-ceramic, flowable composite resin, and gutta-percha presented the least deformation and maintained their cubic shapes. The results of the present study may imply that flowable composite resin compared to all ceramic materials, amalgam and gutta-percha may be a preferable choice when utilized as fiducial markers under CBCT images.

Reliable Location of Upper Extremity Lymphatic Channels for Use in Immediate Lymphatic Reconstruction.

Breast cancer-related lymphedema (BCRL) is a limiting sequelae of breast cancer treatment that may negatively impact 30% to 50% of high-risk breast cancer survivors. Risk factors for development of BCRL include axillary lymph node dissection (ALND), and recently, axillary reverse lymphatic mapping and immediate lymphovenous reconstruction (ILR) at time of ALND have been implemented to prevent BCRL. Reliable anatomy of neighboring venules has been commented on in the literature; however, little information exists about anatomical location of local lymphatic channels amenable for bypass. After institutional review board approval, patients who underwent ALND with axillary reverse lymphatic mapping and ILR at a tertiary cancer center from November 2021 to August 2022 were applicable for this study. The location and number of lymphatic channels used for ILR were identified and measured intraoperatively with the arm abducted to 90 degrees and soft tissue under no tension. Four measurements were taken to localize each lymphatic and were based on relationship with reliable anatomic landmarks including 4th rib, anterior axillary line, and lower border of the pectoralis major muscle. Demographics, oncologic treatments, intraoperative factors, and outcomes were prospectively maintained. Twenty-seven patients met inclusion for this study by August 2022 with a total of 86 lymphatic channels identified. Patients were on average 50 ± 12 years old with a body mass index of 30 ± 6 and had an average of 1 vein and 3 identifiable lymphatic channels amenable to bypass. Seventy percent of lymphatic channels were found in a cluster of 2 or more channels. The average horizontal location was 4.5 ± 1.4 cm lateral to the 4th rib. The average vertical location was 1.3 ± 0.9 cm from the superior border of the 4th rib. These data comment upon intraoperatively identified and consistent location of upper extremity lymphatic channels used for ILR. These lymphatic channels are often found in clusters with 2 or more lymphatic channels at the same location. Such insight may aid in easier intraoperative identification of amenable vessels for the unexperienced surgeon, decrease in intraoperative time, and higher success of ILR.

The Deep-MCL Line: A Reliable Anatomical Landmark to Optimize the Tibial Cut in UKA.

The extramedullary guides for the tibial resection during medial unicompartmental knee arthroplasty (UKA) are inaccurate, with an error risk in coronal and sagittal planes and cut thickness. It was our hypothesis that the use of anatomical landmarks for the tibial cut can help the surgeon to improve accuracy. The technique described in this paper is based on the use of a simple and reproducible anatomical landmark. This landmark is the line of insertion of the fibers of the deep medial collateral ligament (MCL) around the anterior half of the medial tibial plateau called the "Deep MCL insertion line". The used anatomical landmark determines the orientation (in the coronal and sagittal planes) and the thickness of the tibial cut. This landmark corresponds to the line of insertion of the fibers of the deep MCL around the anterior half of the medial tibial plateau. A consecutive series of patients who underwent primary medial UKA between 2019 and 2021 were retrospectively reviewed. A total of 50 UKA were included. The mean age at the time of surgery was 54.5 ± 6.6 years (44-79). The radiographic measurements showed very good to excellent intra-observer and inter-observer agreements. The limb and implant alignments and the tibial positioning were satisfying, with a low rate of outliers and good restoration of the native anatomy. The landmark of the insertion of deep MCL constitutes a reliable and reproducible reference for the tibial cut axis and thickness during medial UKA, independent of the wear severity.

Application of transverse acetabular ligament in total hip arthroplasty: a systematic review

IntroductionIn total hip arthroplasty (THA), the correct position of the acetabular component directly determines the outcome of the surgery, or the success of the surgery. Therefore, how to accurately locate the position of the acetabular component has become a very critical step in THA. As an important anatomical structure of the hip joint, the transverse acetabular ligament (TAL) is helpful for acetabular component orientation in THA. The aim of this systematic review was to investigate application of TAL in THA.Materials and methodsA systematic literature search of PUBMED, EMBASE, and Cochrane Library was performed (January and February 2023) using keywords “total hip arthroplasty,” “total hip replacement,” “total hip replacements,” “total hip arthroplasties,” “total hip prosthesis,” and “transverse acetabular ligament” in all possible combinations. Reference lists of included articles were reviewed. Study design, surgical approach, patient demographics, TAL identification rate, appearance of the TAL, anteversion and inclination angle and rate of dislocations were recorded.ResultsIn total, 19 studies met the screening criteria. Study designs were prospective cohorts (42%), retrospective cohorts (32%), Case series (21%), and randomized controlled trial (5%). Twelve of the 19 (63.2%) studies investigated the application of TAL as an anatomical landmark for locating acetabular component position in THA. Analysis revealed that TAL is a reliable anatomical landmark for acetabular component orientation within the safe zone in THA.ConclusionsTAL can reliably be used to align the acetabular component in the safe zone for anteversion and inclination in THA. However, TAL has individual variation influenced by some risk factors. More randomized controlled studies with larger numbers of patients are needed to investigate the precision and accuracy of TAL as an intraoperative landmark in THA.Level of evidenceIV.