Important Anatomical Structures Research Articles

Simultaneous segmentation of the optic disc and fovea in retinal images using evolutionary algorithms

In this work, we present a new methodology to simultaneously segment anatomical structures in medical images. Additionally, this methodology is instantiated in a method that is used to simultaneously segment the optic disc (OD) and fovea in retinal images. The OD and fovea are important anatomical structures that must be previously identified in any image-based computer-aided diagnosis system dedicated to diagnosing retinal pathologies that cause vision problems. Basically, the simultaneous segmentation method uses an OD-fovea model and an evolutionary algorithm. On the one hand, the model is built using the intra-structure relational knowledge, associated with each structure, and the inter-structure relational knowledge existing between both and other retinal structures. On the other hand, the evolutionary algorithm (differential evolution) allows us to automatically adjust the instance parameters that best approximate the OD-fovea model in a given retinal image. The method is evaluated in the MESSIDOR public database. Compared with other recent segmentation methods in the related literature, competitive segmentation results are achieved. In particular, a sensitivity and specificity of 0.9072 and 0.9995 are respectively obtained for the OD. Considering a success when the distance between the detected and actual center is less than or equal to $$\eta$$ times the OD radius, the success rates obtained for the fovea are 97.3% and 99.0% for $$\eta =1/2$$ and $$\eta =1$$ , respectively. The segmentation average time per image is 29.35 s.

Radiological middle turbinate variations and their relation to nasal septum deviation in asymptomatic adult

BackgroundMiddle turbinate (MT) is one of the important anatomical and physiological structures of the nasal cavity. After the widespread use of nasal endoscope and paranasal sinus computed tomography (CT), many MT variations have been described. This study aimed to determine the incidence of MT variations by computed tomography (CT) in asymptomatic adult, their relation to each other, and to deviated septum (DS).ResultsIn the included 86 subjects (172 MTs), pneumatized MT was the most common MT variation followed by paradoxical MT (PMT). Septal deviation did not appear to affect occurrence of pneumatized or PMT. Fifty-nine percent of the reported bilateral PMT were associated with pneumatized MT, while 35.7% of unilateral PMT were associated with pneumatized MT with non-significant difference.ConclusionMT variations in adults are common mainly pneumatized MT then PMT with no apparent relation to septum deviation.

24-Epibrassinolide Positively Modulate Leaf Structures, Antioxidant System and Photosynthetic Machinery in Rice Under Simulated Acid Rain

Acid rain causes significant damage to rice plants, affecting the photosynthetic machinery and growth. 24-epibrassinolide (EBR) is an organic steroid, which, used at low concentrations, positively regulates plant growth and mitigates deleterious effects related to environmental changes. The aim of this study was to investigate whether exogenous treatment with 24-epibrassinolide can alleviate the negative effects of simulated acid rain (SAR) and the possible tolerance mechanism involved by evaluating chlorophyll fluorescence, gas exchange, the antioxidant system and leaf anatomical variables. The experiment was randomized with four treatments: two simulated acid rain treatments (0 and 0.5 M H2SO4, described as − SAR and + SAR, respectively) and two concentrations of brassinosteroids (0 and 100 nM EBR, described as − EBR and + EBR, respectively). Our results show that plants exposed to SAR suffered negative interferences; however, EBR-treated plants presented benefits related to chlorophyll fluorescence, alleviation of the photoinhibition in photosystem II and protection against damage caused by the imbalance of reactive oxygen species. Additionally, EBR promoted increases in gas exchange that were clearly linked to stomatal regulation, improving the uptake and distribution of CO2 in intercellular spaces. This research revealed that EBR attenuated the negative effects of SAR, increasing the activities of superoxide dismutase (12%), catalase (17%), ascorbate peroxidase (17%) and peroxidase (33%), reducing thylakoid membrane damage, as confirmed by increases in chlorophyll and carotenoids. Finally, the effects of EBR observed in plants under SAR demonstrate that this substance positively modulated important anatomical structures linked to leaf protection, increasing trichome density (8%), epicuticular wax (48%) and the aerenchyma area (100%). These results provide evidence that EBR confers tolerance to rice plants exposed to SAR.

Decompression of Large Cyst Invading the Mandibular Canal Leading to Reduced Cyst Volume and Increased Mandibular Canal Length

The mandibular canal is damaged by the growth of cysts, and remodeling of the mandibular canal is observed as the size of the cyst decreases after decompression procedures. This study aimed to estimate changes in cyst volume and mandibular canal length using cone-beam computed tomography (CBCT) before and after decompression surgery. A retrospective cohort study was conducted in patients with a diagnosis of mandibular cyst invading the mandibular canal between 2012 and 2018. All patients underwent CBCT at the initial visit and after decompression. The predictor variable was the period before decompression and before enucleation surgery. The outcome variables were changes in cyst volume and mandibular canal length, which were evaluated 3-dimensionally. The initial volume of the cyst, initial length of the mandibular canal, and patient's age were set as variables of interest that affected the outcome. Decompression was performed in 20 patients (18 male and 2 female patients), and the mean decompression duration was 8.81±2.94months. The average volume reduction rate after decompression was 60.23%, with an average volume reduction speed of 0.72mL/month. The average length increase rate after decompression was 50.88%, and the average speed of length increase was 2.68mm/month. The initial volume of the cyst and initial length of the mandibular canal were the important variables affecting the results. Complete separation of the mandibular canal from the cyst was observed in 11 cases, and incomplete separation was found in9. Separation from the cyst and regeneration of the mandibular canal using decompression were observed using 3-dimensional CBCT analysis. The results of this study suggest that decompression is effective in separating and preserving important anatomic structures invaded by the cyst.

Application of imaging technique in thoracic duct anatomy.

The thoracic duct is an important anatomical structure of the abdomen, chest and neck. An accurate understanding of the anatomy of the thoracic duct is critical to ensuring the safety and accuracy of the surgical procedure involving these areas, which can help surgeons reduce accidental injuries and provide more accurate diagnosis and intervention for patients with serious complications such as chylothorax, etc. In addition, it has great reference value to know the anatomy of thoracic duct in advance for the selection of treatment strategies in the treatment of refractory pleural effusion and ascites, chylothorax, and heart failure. Therefore, it is of practical value to be able to perform in vivo lymphangiography before surgery. However, the slender thoracic duct, the hidden position and the complicated anatomical structure variations pose a great challenge to the safety and accuracy of the surgical operation. This paper aims at a comprehensive discussion about anatomic variation of thoracic duct and the development of imaging techniques.

The blue mussel inside: 3D visualization and description of the vascular-related anatomy of Mytilus edulis to unravel hemolymph extraction

The blue mussel Mytilus edulis is an intensely studied bivalve in biomonitoring programs worldwide. The lack of detailed descriptions of hemolymph-withdrawal protocols, particularly with regard to the place from where hemolymph could be perfused from, raises questions regarding the exact composition of aspirated hemolymph and does not exclude the possibility of contamination with other body-fluids. This study demonstrates the use of high resolution X-ray computed tomography and histology combined with 3D-reconstruction using AMIRA-software to visualize some important vascular-related anatomic structures of Mytilus edulis. Based on these images, different hemolymph extraction sites used in bivalve research were visualized and described, leading to new insights into hemolymph collection. Results show that hemolymph withdrawn from the posterior adductor muscle could be extracted from small spaces and fissures between the muscle fibers that are connected to at least one hemolymph supplying artery, more specifically the left posterior gastro-intestinal artery. Furthermore, 3D-reconstructions indicate that puncturing hemolymph from the pericard, anterior aorta, atria and ventricle in a non-invasive way should be possible. Hemolymph withdrawal from the heart is less straightforward and more prone to contamination from the pallial cavity. This study resulted simultaneously in a detailed description and visualization of the vascular-related anatomy of Mytilus edulis.

Topographic-Anatomical Validation of a New Method for Minimally-Invasive Extra-Cortical Osteosynthesis Using Plastinated Transverse Shoulder Cuts

The aim of the studywas to assess capability and benefits of this method, its technical feasibility and safety regarding a damage of the most essential anatomical structures.Material and methods.The study involved 15 natural humeral bones; their parameters - the length and shape of the plates – were measured for osteosynthesis. Bone osteosynthesis was further performed on 14 intact upper limbs taken from 7 non-fixed corpses of people died at the age of 63–77 using the discussed method; after that, the operated limbs were studied using preparating technique. Furthermore, after plate application on two shoulder sections, 12 transverse cuts with their epoxy plastination were made at three levels according to the original technology; this was followed by the preparation of histotopographic sections.Results.The results obtained have demonstrated that for the new method of bone osteosynthesis it is advisable to use metal plates 220–260 mm long with spiral twisting clockwise for the right humerus and counterclockwise for the left. Average distances from the fixed plate to the humerus, tendon of the long head of the biceps of the shoulder muscle, large blood vessels and peripheral nerves were determined using precision preparation and measurements; the measurements were also performed on transparent plate-shaped shoulder cuts. All the above validates safety of the discussed method regarding a damage of the most essential anatomical structures and allow to successfully use it in the clinical practice.Conclusion.The discussed technique of plastinated transverse shoulder cuts with further experimental fixation of metal implants for osteosynthesis ensures safety of the initial topographic and anatomical relationships of these structures with anatomical structures. In addition, high transparency of the tissues created by epoxy plastination allows determining distances between implants and important anatomical structures with high precision, the fact being of great significance in applied anatomical studies.

CLINICAL AND RADIOGRAPHIC OUTCOMES OF RADICULAR CYST ENUCLEATION USING PIEZOSURGERY VERSUS CONVENTIONAL SURGERY

Abstract AIM: The study was intended to evaluate the effectiveness of piezosurgery in enucleation of radicular odontogenic cysts in comparison to the conventional technique. METHODS: Fourteen patients who had radicular cysts associated with non-vital teeth, were operated at the Oral and Maxillofacial Surgery Department, Faculty of Dentistry, Alexandria University. The patients were randomly divided into 2 groups;1) the study group in which cyst enucleation was using piezosurgery, 2) control group in which the cysts were removed using the conventional technique. The following were assessed; operation time, hemorrhage control and field visibility, ease of operation, neurosensory evaluation and radiographic percentage of change in bone defect volume. RESULTS: The piezosurgery group showed a statistically significant control over heamorrhage and a clearer, more visible field when compared to the conventional group. The difference between the times required for cyst enucleation in both groups was statistically significant, with longer time recorded with piezosurgery. No complications were observed with the piezosurgery technique. However, with the conventional technique, 2 patients complained of neurosensory involvement which was resolved over time. Also, with piezosurgery, there was a significant reduction of bone defect volume than the conventional surgery, 3 months after the operation in comparison to the preoperative baseline value. CONCLUSIONS: Piezosurgery proved to be more effective for cyst enucleation than the conventional method. The piezosurgery was more efficient for preserving important anatomical structures while providing a clearer field of surgery. Also, better early healing potential of the bone defect resulting from cyst enucleation was detected.

Learning the retinal anatomy from scarce annotated data using self-supervised multimodal reconstruction

Deep learning is becoming the reference paradigm for approaching many computer vision problems. Nevertheless, the training of deep neural networks typically requires a significantly large amount of annotated data, which is not always available. A proven approach to alleviate the scarcity of annotated data is transfer learning. However, in practice, the use of this technique typically relies on the availability of additional annotations, either from the same or natural domain. We propose a novel alternative that allows to apply transfer learning from unlabelled data of the same domain, which consists in the use of a multimodal reconstruction task. A neural network trained to generate one image modality from another must learn relevant patterns from the images to successfully solve the task. These learned patterns can then be used to solve additional tasks in the same domain, reducing the necessity of a large amount of annotated data.In this work, we apply the described idea to the localization and segmentation of the most important anatomical structures of the eye fundus in retinography. The objective is to reduce the amount of annotated data that is required to solve the different tasks using deep neural networks. For that purpose, a neural network is pre-trained using the self-supervised multimodal reconstruction of fluorescein angiography from retinography. Then, the network is fine-tuned on the different target tasks performed on the retinography. The obtained results demonstrate that the proposed self-supervised transfer learning strategy leads to state-of-the-art performance in all the studied tasks with a significant reduction of the required annotations.

High Division of the Median Nerve with Unusually High Origin of the 3rd Space Common Digital Nerve

BackgroundMedian nerve (MN) variation in the carpal tunnel has been well documented by Lanz. Encountering rarely documented variants, that do not fit into existing classifications, increases the risk of iatrogenic injury. MethodsThe random occurrence of two unclassifiable anatomical variants of the MN in the carpal tunnel gives motivation to search the literature for similar and identical cases. Case reportsThis article presents two cases of very rare anatomical variants of high division of the MN. First case is a pure high branching of the 3rd space common digital nerve (CDN). The second case is a high division of the MN to a thicker lateral component and a thinner medial component. The lateral component of the MN gives off the palmar cutaneous branch (PCB), the thenar motor branch (TMB), the 1st and 2nd space CDN's and contributes medially with a branch to the 3rd space CDN. The medial component of the MN bifurcates distally into a medial and lateral branch. The lateral branch from the medial component of the MN distally unites with the medial branch of the lateral component of the MN to form the 3rd space CDN. The medial branch from the medial component of the MN has a major contribution to the 4th space CDN from the ulnar nerve. In both cases, the medial component of the MN has a transmuscular course through the flexor digitorum superficialis (FDS) muscle. DiscussionFinding similar case reports from worldwide suggests the need to improve current classification of the MN variants in the carpal tunnel. ConclusionsOne cannot rely entirely on the existing anatomical classifications of the MN in the carpal tunnel. There is an underappreciated risk of iatrogenic injury, especially in endoscopic carpal tunnel release, and a chance of missing out on repair of important anatomical structures in trauma cases. There is a possibility of augmenting group 3 of Lanz's classification by adding subgroup “3D High division of the MN with the medial component having a transmuscular course through the FDS muscle”, stating the different distal branching patterns.

Application of Computer-Aided Navigation Technology in the Extraction of Foreign Body From the Face.

In the oral and maxillofacial foreign body (FB) extraction surgery, computer-aided navigation technical surgery is minimally invasive and safe, and can improve the accuracy, especially for areas with relatively complex and dangerous anatomical structures. A total of 11 patients, including 8 males and 3 females, who underwent the extraction surgery of FB from oral and maxillofacial regions using computer-aided navigation technical surgery were reviewed. According to the positional relationship between the maxillofacial region and the bone tissue, the FBs were divided into 3 categories: FB in the bone; FB aside the bone; and soft-tissue FB. During the operation, the BrainLab Navigation system was used to observe and guide the operation in real-time to evaluate the effectiveness and accuracy of computer-aided navigation technical surgery in the extraction of FBs from the maxillofacial regions. The FBs were successfully located and removed in 11 patients. No adjacent nerves, blood vessels, and other important anatomical structures were injured during the operation. The postoperative function and shape were not significantly affected.

Biplane Fluoroscopic-Guided Balloon Rhizotomy for Trigeminal Neuralgia: A Technical Note.

The classic percutaneous technique used to cannulate the foramen ovale for the treatment of trigeminal neuralgia can place important anatomic structures, such as the distal cervical internal carotid artery, at risk. To use fixed anatomic landmarks to safely and reliably locate the foramen ovale on anteroposterior (AP) fluoroscopy. Locating the foramen ovale was initially tested using AP fluoroscopy on cadaveric skulls in the neurosurgical simulation lab. Fluoroscopic landmarks were identified and utilized to assist in successfully locating the foramen ovale during percutaneous balloon rhizotomy procedures in patients with trigeminal neuralgia. This technique has been successfully used in multiple patients. In this report, we describe our technique in detail. The AP fluoroscopy is directed laterally in the coronal plane until a line drawn inferiorly from the lateral orbital rim bisects the inner concavity of the mandibular angle. Fluoroscopy is then directed inferiorly until the top of the petrous ridge bisects the mandibular ramus. The foramen ovale will come into view within the window between the mandibular ramus and hard palate. Two case illustrations are provided. Balloon rhizotomy is a commonly used treatment option for trigeminal neuralgia. Direct visualization of the foramen ovale can reliably be achieved on AP fluoroscopy using specific anatomic landmarks. This technique can be utilized to increase the accuracy and safety of the procedure.

Shapes and Sizes of Sella Turcica Using Computerized Tomography (CT) from Tertiary Hospital in Sokoto, Nigeria

Cephalometry deals with measurement of body parts or radiological specimen. Sella turcica is an important anatomical structure located in the middle cranial fossa, housing the pituitary gland. Various shapes and sizes of the sellae turcica were reported. In this study, using computerized tomographic (CT) scans from a tertiary hospital, one hundred and seventy five (175) scans were analyzed using Radiant version 4.2 (Medixant 2017) for determination of sizes and shapes of the sella. Average dimensions from the study include: Length (12.4 mm), A-P diameter (14.1 mm), depth (9.6 mm) and transverse diameter (13.8 mm). Shapes were classified as being round (56.6%), oval (32%) and flat (11.4%). In another classification of shape variation, the findings are: Normal (68.6%), anterior oblique (9.1%), pyramidal (6.9%), double contour floor (5.7%), notching on the posterior wall (5.1%) and sella bridge (4.6%). Males tend to have higher sella sizes than females and there is statistical significant difference between them especially in respect to A-P diameter and length parameters. However, there is no sex predilection to shapes.

Computer-Assisted Preoperative Simulations and 3D Printed Surgical Guides Enable Safe and Less-Invasive Mandibular Segmental Resection: Tailor-Made Mandibular Resection

This study aimed to present and evaluate alternative lesion-specific mandibulectomy methods for preserving the mandibular anatomical structures as compared with the conventional virtual surgical plan. Fifteen patients who received segmental mandibulectomy were included in this study, and the following parameters were evaluated: (1) the disease-free bone margin, (2) the volume and surface between the tailor-made resection simulation and conventional resection simulation, and (3) the preserved mandibular anatomical structures. In all 15 patients, disease-free bone margins were confirmed by histopathology. Volumes of conventional resection simulation and tail-made resection simulation were 49,468.66 ± 14,007.96 mm3 and 52,610.01 ± 13,755.33 mm3 and the surfaces were 20,927.38 ± 4471.70 mm2 and 22,356.49 ± 4185.73 mm2, respectively; these were statistically significant (both, p < 0.001). Mandibular dentition was partially preserved in six patients. Twelve of the 15 patients had changes in defect classification with preservation of the mandibular inferior border. In conclusion, alternative lesion-specific mandibulectomy was a less invasive method for effectively removing mandibular lesions while preserving the important anatomical structures of the mandible.

Research and surgical application of fluorescent contrast agents

In recent years, the use of fluorescent contrast agents staining to guide surgery has flourished in various fields of surgery under the concept of precision surgery, which is helpful to guide surgery and provide surgeons with actual visible fluorescence imaging.Clinically, fluorescent contrast agent can be used to display tumor’s outline with high recognition degree, guide operation in real time, locate lymph node metastasis, detect small metastases, and identify important anatomical structures during the operation to avoid possible side-injury. Great progress has been made in the study of fluorescent contrast agents that can mediate surgery, including the study and surgical application development of classical fluorescent contrast agents such as indocyanine green and methylene blue, etc, as well as the discovery and clinical application of new targeted fluorescent contrast agents such as folate receptor targeting contrast agents, monoclonal antibody based fluorescent targeting contrast agents and intelligent contrast agents, etc. This paper will review the research and surgical application of fluorescent contrast agents in two aspects: classical fluorescent contrast agents and new targeted fluorescent contrast agents. Key words: Fluorescent dyes; Surgical procedures, operative; Fluorescent contrast agent; Fluorescent guided surgery; Fluorescence imaging

Application of holographic image navigation in urological laparoscopic and robotic surgery

Objective To evaluate the clinical value of holographic image navigation in urological laparoscopic and robotic surgery. Methods The data of patients were reviewed retrospectively for whom accepted holographic image navigation laparoscopic and robotic surgery from Jan. 2019 to Dec. 2019 in Beijing United Family Hospital and other 18 medical centers, including 78 cases of renal tumor, 2 cases of bladder cancer, 2 cases of adrenal gland tumor, 1 cases of renal cyst, 1 case of prostate cancer, 1 case of sweat gland carcinoma with lymph node metastasis, 1 case of pelvic metastasis after radical cystectomy. All the patients underwent operations. In the laparoscopic surgery group, there were 27 cases of partial nephrectomy, 1 case of radical prostatectomy, 2 cases of radical cystectomy and 2 cases of adrenalectomy. In the da Vinci robotic surgery group of 54 cases, there were 51 cases of partial nephrectomy, 1 case of retroperitoneal lymph node dissection, 1 case of retroperitoneal bilateral renal cyst deroofing and 1 case of resection of pelvic metastasis. There were 41 partial nephrectomy patients with available clinical data for statistic, with a median age of 53.5 years (range 24-76), including 26 males and 15 females. The median R. E.N.A.L score was 7.8 (range 4-11). Before the operation, the engineers established the holographic image based on the contrast CT images and reports. The surgeon applied the holographic image for preoperative planning. During the operation, the navigation was achieved by real time fusing holographic images with the laparoscopic surgery images in the screen. Results All the procedures had been complete uneventfully. The holographic images helped surgeon in understanding the visual three- dimension structure and relation of vessels supplying tumor or resection tissue, lymph nodes and nerves. By manipulating the holographic images extracorporeally, the fused image guide surgeons about location vessel, lymph node and other important structure and then facilitate the delicate dissection. For the 41 cases with available clinical data including 23 cases of robotic-assisted partial nephrectomy and 18 cases of laparoscopic nephrectomy, the median operation time was 140(range 50-225)min, the median warm ischemia time was 23(range 14-60)min, the median blood loss was 80(range 5-1 200)ml. In the robotic surgery group, the median operation time was 140(range 50-215)min, the median warm ischemia time was 21(range 17-40)min, the median blood loss was 150(range 30-1 200)ml. In the laparoscopic surgery group, the median operation time was 160(range 80-225)min, the median warm ischemia time was 25(range 14-60)min, the median blood loss was 50(range 5-1 200)ml. All the patients had no adjacent organ injury during operation. There were 2 cases with Clavien Ⅱcomplications. One required transfusion and the other one suffered hematoma post-operation. However, the tumors were located in the renal hilus for these 2 cases and the R. E.N.A.L scores were both 11. Conclusions Holographic image navigation can help location and recognize important anatomic structures during the surgical procedures.. This technique will reduce the tissue injury, decrease the complications and improve the success rate of surgery. Key words: Laparoscopic; 3 dimension image reconstruction; Holographic Imaging; Laparoscopic surgery; Robotic surgery

Ultrasonography for diagnosis of peri-implant diseases and conditions: a detailed scanning protocol and case demonstration.

Ultrasonography has shown its promising diagnostic value in dental implant imaging research in the three treatment phases, namely, planning, intraoperative, and postoperative phase. With increasing awareness of peri-implant diseases and a lack of an efficient diagnostic method, the aim is to propose ultrasound imaging as a potential solution by providing a detailed scanning protocol and case demonstration. Ultrasound device specification and the setup for optimizing peri-implant tissue imaging was described. Two useful imaging modes, viz. B-mode and color flow, were introduced. Important anatomical structures for accurate diagnosis of peri-implant diseases were illustrated. Finally, a detailed scanning sequence was proposed. Ultrasound images were acquired on live humans to exemplify the four peri-implant diseases and conditions, endorsed by the 2017 World Workshop organized by the American Academy of Periodontology and the European Federation of Periodontology. Ultrasound can provide not only cross-sectional anatomical images but also functional images (color flow images) that may be useful for evaluating the degree of peri-implant tissue inflammation. High-frequency ultrasonography could be another cross-sectional imaging modality in adjunct to radiographs for diagnosing imminent peri-implant diseases and conditions that negatively influence quality of life of millions of patients with implants. This case study provides a framework for future related research work and clinical scanning guidelines.

Considering the ‘Multi‐layered’ theory of Denonvilliers’ fascia: how to approach for neurovascular bundle preservation on performing rectal mobilization (cadaveric study)

Denonvilliers’ fascia, an important and yet, controversial structure, was first noted by a French Surgeon, Charles-Pierre Denonvilliers after a series of anatomical dissections of the perineum in 1936 1, 2. This structure is vital for colorectal surgeons as the understanding of it would significantly improve the oncological and functional outcomes after rectal cancer surgery. In the classical description of the total mesorectal excision (TME), Professor Heald advocated that the dissection plane should be in front of the Denonvilliers’ fascia during anterior mobilisation of the low rectum 3. Professor Bokey, amongst others, suggested this layer should be left intact, unless when dealing with locally advanced, anteriorly located tumours 4. A pragmatic approach was proposed by Professor Mortensen’s group in Oxford when performing anterior mobilisation of the low rectum 5. In this issue, Ghareeb et al. 6, on reviewing their videos of low anterior resection, noted the presence of multiple fascial layers in the pre-rectal space, went on to study 18 newly fixed male and female cadavers, with a binocular loupe for a more detailed dissection. They have confirmed the multi-layered theory of Denonvilliers’ fascia, as opposed to ‘fusion’ or ‘condensation’ of embryonic connective tissues. The authors proposed their technique to initiate the anterior rectal mobilisation by making an incision a few millimetres posterior to the peritoneal reflection to minimise the injuries to the neurovascular bundles. The study also provided insight into the mysteries of the Denonvilliers’ fascia in females. This cadaveric study has added further evidence and understanding of this important anatomical structure. With the advancement of surgical equipment, including ever-improving higher resolution imaging with a magnified view; we are in a better position and equipped to provide a more precise surgical dissection.

Maturity evaluation of orthodontically important anatomic structures with computed tomography

The success of the orthopaedic treatment is closely related to the patient's skeletal maturation. This study aimed to evaluate the midpalatal suture (MPS), the zygomaticomaxillary suture (ZMS) maturation, and the closure degree of the spheno-occipital synchondrosis (SOS) in patients of different age groups. The presence of a correlation between these parameters and the palatal dimensions was also verified. The study was based on computed tomography images of 314 patients between 7 and 30 years of age with no orthodontic treatment history. The images were retrieved from the archive of the Radiology Department of Bezmialem Vakif University Hospital and divided into six groups according to the patient's age: 7-10, 11-13, 14-16, 17-20, 21-25, and 26-30 years. The maturation scores of ZMS, SOS, and MPS were determined, and palatal thickness and length were recorded. The data were analysed by using Statistical Package for Social Sciences for Windows 22.0. A positive relationship was found between SOS closure degree and MPS/ZMS maturation (MPS-ZMS: r = 0.816, MPS-SOS: r = 0.736, ZMS-SOS: r = 0.868, P = 0.000). The degrees of ZMS and MPS maturation were significantly increased as the SOS closure degree increased. The MPS maturation score was significantly lower in patients with a short and thick palate (MPS-palatal thickness: r = 0.405, MPS-palatal length: r = 0.387, P = 0.000). A positive correlation indicated the simultaneous progress in the maturation of the SOS, MPS, and ZMS. Moreover, the ANS-PNS length increase was found to be correlated with the increase of the MPS, ZMS, and SOS maturation scores. In contrast, a negative correlation was observed between the palatal thickness and the maturation stage of these structures.

Analysis of the Anatomic Relationship Between the Mandibular First Molar Roots and Mandibular Canal Using Cone-Beam Computed-Tomography in 101 Dogs.

The mandibular first molar (M1) tooth of the dog is commonly involved in dental procedures. Tooth roots and the mandibular canal can vary in location, which has not been described on a large scale. The objective of this study was to describe the three-dimensional anatomic relationship of the mandibular M1 tooth roots and the mandibular canal in dogs. Cone-beam computed tomography (CBCT) was used to evaluate the anatomic relationship between the M1 tooth roots and the mandibular canal. CBCT images were collected from 101 canine cadaver heads from a variety of unknown breeds. All skulls used in this study were mesaticephalic, confirmed by facial index calculations. The position of the apex in relation to the mandibular canal and in relation to the buccal and lingual cortices was recorded and analyzed in relation to mandibular bone height: root length ratio. When evaluating the apex in a buccal-lingual relationship, the tooth roots were found to be located closer to the lingual cortex in 73.3% of M1 roots. Tooth root apical positions were found to be symmetric between the right and left side of the mouth in 93% of mesial roots and 95% of distal roots. Apical positions relative to the mandibular canal within the same tooth were found to be consistent in 52% of teeth. Teeth with roots dorsal to the mandibular canal were associated with the largest mandibular bone height: root length ratio. CBCT provides a more precise overview than dental radiographs of three-dimensional anatomy. The tooth root position can be estimated in a clinical setting based on the ratio of mandibular bone height to tooth root length obtained from intraoral radiographs. Understanding the relative location of important anatomic structures is key to avoiding complications associated with various dental procedures. This study has documented that assessing anatomic structures with 2D imaging alone is flawed, and the large majority of dogs have M1 roots closer to the lingual aspect than the buccal aspect of the mandible.