Posterior Border Research Articles

Morphology of the greater palatine foramen: a clinical point of view.

Anatomical characteristics of the greater palatine foramen (GPF) are essential during the greater palatine nerve block application to anesthetize maxillary teeth, gums, midface, and nasal cavities. The position of GPF is usually described in relation to adjacent anatomical structures. This investigation aims to examine the morphometric relationships of GPF and closely determine its position. The study included 87 skulls (174 foramina). They were photographed in a horizontal position with bases facing up. The digital data were processed in the ImageJ 1.53n software. The average distance of the GPF from the median palatine suture was 15.94mm. In relation to the posterior border of the bony palate, the distance was 2.05mm. Statistical significance was found in comparing the angle between the GPF, incisive fossa, and the median palatine suture between the sides of the skulls (p = 0.02). Comparing tested parameters between males and females showed significant differences in GPF-MPS (p = 0.003) and GPF-pb (p = 0.012), with lower values in females. The most significant percentage of skulls (77.01%) had the GPF located at the level of the third molar. The most significant number of bony palates had one lesser opening (60.91%) on the left side. GPF is located at the level of the maxillary third molar in most of the examined palates. Knowledge of the anatomical position of the greater palatine foramen and its variations is the basis for successfully implementing anesthesia and various surgical interventions.

Extended Trochanteric Osteotomy in Revision Total Hip Arthroplasty.

Extended Trochanteric Osteotomy in Revision Total Hip Arthroplasty.

Posterior Approach for Open Reduction and Internal Fixation for Scapular Fractures.

This technique utilizes a full-thickness flap to provide a posterior approach to the scapula for open reduction and internal fracture fixation. The present video article outlines the Judet approach along with an incision modification tip for the surgeon's consideration. Prior to making the incision, perform preoperative planning, patient and C-arm positioning, and identification of the primary fragments of the fracture that necessitate fixation on imaging. The Judet incision is made, and the full-thickness flap is retracted laterally (also described as a "boomerang-shaped" incision, allowing for the flap to be reflected medially). Next, detach and reflect the deltoid off the scapular spine superolaterally to reveal the internervous plane between the infraspinatus and teres minor. Utilize this interval to access the fracture sites while making sure to reflect the infraspinatus cranially, carefully minding the suprascapular neurovascular bundle, and the teres minor inferiorly, protecting the axillary nerve. A longitudinal arthrotomy may then be created parallel to the posterior border of the glenoid, with careful attention paid toward protecting the labrum from iatrogenic injury. The arthrotomy will allow for intra-articular evaluation of the reduction if needed. Primary fractures are then reduced. Reduction is confirmed with use of fluoroscopy, and fixation is applied to maintain the reduction. Most scapular fractures do well with nonoperative treatment, and this has been well documented in the literature. Open reduction and internal fixation has been shown to offer good-to-excellent clinical outcomes with minimal risk of complications in patients with traumatic scapular fractures that necessitate operative treatment1. In certain fractures of the glenoid fossa, operative treatment is necessary to restore normal anatomy, provide stability to the glenohumeral joint, and facilitate functional rehabilitation. Operative treatment is typically reserved for injuries with intra-articular involvement that results in joint incongruity or joint instability2,3. When operative treatment is indicated, an open posterior approach is utilized for some fractures. The posterior Judet approach is the best-known operative technique for such fractures, while other modifications of the Judet technique have also been described in the literature3-5. Reports state that scapular body or neck and glenoid fossa fractures account for up to 80% of scapular fractures6. Open reduction and internal fixation of the scapula is an invasive procedure, requiring large incisions and manipulation of soft tissues to expose the various possible fracture sites on the scapula. Thus, numerus surgical techniques have been described that allow surgeons to best tailor treatment to their patients on a case-by-case basis. However, the Judet approach is the workhorse approach for the operative treatment of scapular fractures and is a technique that should be mastered7. The Judet approach allows access to the posterior scapula and provides excellent exposure for fractures that require posterior fixation. The alternative boomerang-shaped incision represents a mirrored version of the Judet incision, with the skin flap reflected medially. The benefit of this modified approach is that it increases the degree of lateral surgical exposure of the scapula and provides easier access to the glenohumeral joint. With this technique for open reduction and internal fixation of scapular fractures, patients can expect comparable outcomes to those described in the literature for the standard Judet technique. These outcomes have been reported as clinical scores and defined as good-to-excellent in a few retrospective case series1,2. Given the variability in scapular fracture morphology, a trauma surgeon should have a strong repertoire of approaches to address these fractures on a case-by-case basis. The Judet approach is one of these necessary approaches and has been shown in the literature to have acceptable outcomes1-3,7. Placing the vertical limb of the boomerang incision too medial can limit lateral exposure of the scapula and make glenohumeral joint access difficult. To avoid this, be sure that the vertical limb of the incision remains in line with the posterior axillary fold.Wound-healing complications can occur following such an extensive surgical approach. A thorough and secure wound closure with repair of the deltoid back to the scapular spine may avoid these problems.Difficulty with intra-articular visualization may occur. Placing a threaded pin into the humeral head or a small distractor across the glenohumeral joint (with a pin in the extra-articular proximal humerus) may improve visualization. Manipulation of the arm can also be beneficial in this regard.Lateral positioning offers easier imaging and allows for exposure to the coracoid or clavicle if these structures are also injured and require operative fixation.Drawing a boomerang-shaped incision with the horizontal limb paralleling the scapular spine and vertical limb along the posterior axillary fold of the arm allows the skin flap to be reflected medially, increasing the degree of lateral surgical exposure of the scapula.After identifying the internervous plane between the infraspinatus and teres minor, take care to reflect the infraspinatus cranially, protecting the suprascapular neurovascular bundle, and the teres minor inferiorly, protecting the axillary nerve. ORIF = open reduction and internal fixationK-wire = Kirschner wire.

INCIPIENT ORAL SQUAMOUS CELL CARCINOMA MIMICKING TRAUMATIC ULCER

Squamous cell carcinoma (SCC) is the main histological type of oral cancer and is usually diagnosed at a late stage. The most common clinical feature is an infiltrating and chronic ulcer with hardened edges. However, it can present other manifestations, mimicking different conditions. Case report: Two Caucasians patients, smokers, 53 and 59 years old, were referred, complaining of tongue sores. Upon clinical examination, superficial ulcers were observed on the posterior lateral border of the tongue. The main diagnostic hypothesis was traumatic ulcers. However, as no improvement was observed after polishing of the cusps (case 1) and extraction (case 2), incisional biopsies were performed and revealed squamous cell carcinoma. Partial glossectomy, neck dissection, and radiotherapy were performed. The two cases exemplify the importance of a correct diagnosis, especially for oral lesions that mimic non-neoplastic processes. Squamous cell carcinoma (SCC) is the main histological type of oral cancer and is usually diagnosed at a late stage. The most common clinical feature is an infiltrating and chronic ulcer with hardened edges. However, it can present other manifestations, mimicking different conditions. Case report: Two Caucasians patients, smokers, 53 and 59 years old, were referred, complaining of tongue sores. Upon clinical examination, superficial ulcers were observed on the posterior lateral border of the tongue. The main diagnostic hypothesis was traumatic ulcers. However, as no improvement was observed after polishing of the cusps (case 1) and extraction (case 2), incisional biopsies were performed and revealed squamous cell carcinoma. Partial glossectomy, neck dissection, and radiotherapy were performed. The two cases exemplify the importance of a correct diagnosis, especially for oral lesions that mimic non-neoplastic processes.

Anatomical Landmarks and Branching Patterns of the Greater Auricular Nerve

Study Design Descriptive cross-sectional study. Background: The greater auricular nerve (GAN) courses over the sternocleidomastoid muscle (SCM) to supply the area of skin over the parotid gland (PG), the lower auricle and over the mastoid. It is vulnerable to injury during rhytidectomies and parotidectomies, resulting in sensory losses and pain. Although previous studies have identified suitable landmarks, injury to the GAN in the Kenyan setting still occurs. This study therefore aimed at identifying specific landmarks for the GAN and describing its branching pattern. Objective: To determine the anatomical landmarks of the GAN and its branching patterns. Methods: Forty six nerves were studied. The skin and fascia of the neck was carefully dissected to reveal the platysma muscle, which was reflected to expose the GAN. The distance of the emergence of the GAN on the posterior border of the sternocleidomastoid muscle as measured from the mastoid process (MP) was measured. Its perpendicular distance from the tragus to the point of branching was also measured. Its distance to the external jugular vein (EJV) was taken using a ruler and a pair of dividers. Finally, the nerve was described according to McKinney’s point. The pattern of branching was described as either type 1 (no branching), type 2 (2 branches) or type 3 (3 branches). The position of branching was classified as either anterior, posterior or middle. Collected data was coded into SPSS software (Version 21.0, Chicago, Illinois), and means ± standard deviation were calculated. Representative photos were taken. Results: The mean distance of the point of emergence of the nerve was 9.13 cm +/− 1.66 cm from the MP, while its distance from the tragus was 6.93 cm +/− 1.55. It was also located at a distance of 1.67 cm from the EJV. It mainly bifurcated into two branches (55.6%) and trifurcated in 4.4% of the cases. It remained undivided in 40% of the cases. In our study, the nerve mainly bifurcates in the anterior third of the SCM (22.2%). Conclusions: The GAN in our population mainly bifurcates, and it is more likely to divide closer to the parotid gland. The data presented in the study may be helpful in avoiding its iatrogenic injury.

A Novel Technique for Resection and Reconstruction of the Temporomandibular Joint by Sliding Vertical Ramus Osteotomy using Only Submandibular Approach.

In this paper, an innovative technique for resection and reconstruction of the temporomandibular joint by sliding vertical ramus osteotomy using only a submandibular approach is presented. Before pulling the posterior mandibular border slightly downward to expose parts of the condyle, the vertical ramus osteotomy was performed. With the help of 3D simulation and surgical templates, the condylectomy was carried out using the ultrasonic osteotome through the submandibular approach. Our technique achieved the desired results while preventing complications of facial nerve paralysis, the occurrence of Frey syndrome, and the preauricular scar. Therefore, we suggest that this surgical method represents an alternative treatment option for temporomandibular joint lesions.

Biomechanical influence of plate configurations on mandible subcondylar fracture fixation: a finite element study.

Mandible subcondylar fractures have very high complication rate, yet there is no consensus on suitable plate design for optimal patient outcomes. Our study is aimed at comparing single mini, trapezoid, lambda, strut and double mini plates. A finite-element (FE) model of intact mandible was developed based on healthy CT-scan data, which was further virtually osteotomized and fixated with plates. The cortical and cancellous bones were assigned region-specific orthotropic and heterogenous isotropic material properties respectively. The models were subjected to six load cases representing the mastication cycle. Under opposite lateralities, the tensile and compressive mandibular strain distributions were found as the opposite, with tensile strains at the posterior border under ipsilateral molar clenching (RMOL) resulting in lesser mandibular strain in reconstructed mandible with single mini plate under RMOL but highest mandibular strain under the contralateral molar clenching (LMOL). Owing to the reduced mandibular strains under LMOL than RMOL, the contralateral chewing is preferred during the immediate post-surgery period for patients. Under LMOL, the peak von Mises stresses in the plate decreased with increase in the number of screws. Furthermore, the presence of two arms in double mini and trapezoid plates seems beneficial to neutralise the tensile and compressive strains across load cases.

The spinal accessory nerve and its entry point into the posterior triangle of the neck.

The course of the spinal accessory nerve in the neck is long and superficial rendering it at high risk of injury during procedures performed in the posterior triangle. The majority of spinal accessory nerve injuries are iatrogenic in nature. This is associated with significant morbidity including reduction in shoulder movements, drooping of the shoulder, winging of the scapula and neuropathic pain. Knowledge of the nerve anatomy reduces the risk of intra-operative nerve injury. Traditional teaching describes the point of entry into the posterior triangle as the intersection between the upper and middle third of the posterior border of sternocleidomastoid. The aim of this study was to determine whether this is in fact the case and if so, whether this landmark can reliably be used to identify the spinal accessory nerve in order to improve patient outcomes. The spinal accessory nerve was identified unilaterally in 26 cadavers. The total length of sternocleidomastoid was measured as well as the length along the posterior border from the inferior aspect of the mastoid process to the point at which the accessory nerve enters the posterior triangle of the neck. These measurements were used to calculate the ratio of the entry point of the nerve into the posterior triangle along the length of the posterior border of sternocleidomastoid from its superior insertion point. The mean ratio was 0.35 with 95% confidence intervals of 0.33 to 0.36. Our findings confirm the traditional description of the entry point of the spinal accessory nerve into the posterior triangle of the neck. We describe a so-called 'safe zone' inferior to the midpoint of the posterior border of sternocleidomastoid within which the spinal accessory nerve is unlikely to be found, thereby reducing the risk of iatrogenic injury.

Retrospective evaluation of the morpometric and morphological anatomy of the occipital condyle, hypoglossal canal and foramen magnum in Turkish populaton with CBCT.

The aim of this study is to morphometrically and morphologically examine the occipital condyle, which is an important anatomical region in terms of surgery and forensic medicine, and its surrounding structures, to evaluate the change in mean values according to gender and age, and to evaluate the correlation of the measurements obtained. 180 (90 men, 90 women) CBCT images selected from the archive of Ankara University Faculty of Dentistry. Occipital Condyle length and width, Hypoglossal Canal-Basion distance, Hypoglossal Canal-Opistion distance, Hypoglossal Canal-Occipital Condyle anterior and posterior border distance, Occipital Condyle thickness, Hypoglossal Canal length, the widest diameter of Hypoglossal Canal, the narrowest diameter of the Hypoglossal Canal, the length of the Jugular Tubercle, the width of the Jugular Tubercle, the anterior intercondylar distance, the posterior intercondylar distance, and the Foramen Magnum index were measured. At the same time, the presence of septum or spicule in the hypoglossal canal and protrusion of the occipital condyle were evaluated. The relationship of age, gender, anterior and posterior intercondylar distance, and foramen magnum index measurements with all measurements were examined. In our study, all measurements were repeated 1month after the first measurements to evaluate the intra-observer agreement, and the agreement between the obtained measurements and the first measurements was evaluated by calculating the intraclass correlation coefficient and 95% confidence intervals. Men's measurements were found to be significantly higher than women's measurements. When the coefficients of concordance in all measurements were examined, it was observed that there was a perfect concordance. When the results of the study are evaluated, it is seen that the values ​​obtained are generally close to the studies related to CT. Considering this, an idea can be gained as to whether CBCT, which has a lower dose and less cost, can be used as an alternative to CT in studies to be conducted with more comprehensive and different methods in skull base surgical planning.

Augmentation of a Nonanatomical Repair of a Medial Meniscus Posterior Root Tear With Centralization Using Three Knotless Anchors May Be Associated With Less Meniscal Extrusion and Better Compressive Load Distribution in Mid-Flexion Compared With Non-Anatomical Root Repair Alone in a Porcine Knee Model

To investigate the biomechanics of the centralization augmentation using knotless soft anchors to a nonanatomicaltranstibial pull-out root repair in a porcine medial meniscus posterior root tear (MMPRT) model. Porcine knee joints (N= 10) were used to perform one of the following procedures: (1) intact; (2) MMPRT; (3) nonanatomical root repair; (4) nonanatomical root repair with centralization using 2 anchors: anchors were inserted at the posterior medial collateral ligament (MCL) border and 10 mm anterior to the posterior MCL border; and (5) nonanatomical root repair with centralization using 3 anchors: another anchor was placed 10 mm posterior to the posterior MCL border. Contact area on the medial meniscus (MM), contact pressure in the MM and tibial cartilage, and MM extrusion were evaluated at 30°, 45°, 60°, and 90° knee flexions under 200 N compressive force. MM extrusion at the posterior MCL border was significantly reduced after root repair with centralization using 3 anchors than after root repair alone at 30° (-0.063 mm vs 1.5 mm, P= .017), 45° (0.21 mm vs 1.7 mm, P= .018), and 60° (0.78 mm vs 2.3 mm, P= .019). There were no significant differences in MM extrusion between the root repair alone and root repair with centralization using 2 anchors at all flexion angles. The contact area in the middle and posterior MM was significantly greater after centralization with 3 anchors than after root repair alone at all flexion angles (except the posterior MM at 90°). The mean contact pressure in the tibial cartilage was significantly lower after centralization with 3 anchors than after root repair at all angles. Augmentation of a nonanatomical repair of a medial meniscus posterior root tear with centralization using three knotless anchors may be associated with less meniscal extrusion and better compressive load distribution between 30° and 60° flexion compared with nonanatomical root repair alone in a porcine model. This biomechanical study at time zero suggests that the addition of centralization using 3 knotless anchors may reduce MM extrusion and restore the load-distributing function of the MM.

Resection of cervical extra-intraspinal neuromas through the enlarged intervertebral foramen: Results in 34 case series patients.

The purpose of this study was to analyze the techniques used to resection cervical extra-intraspinal neuromas (also known as cervical dumbbell neuromas) through the enlarged intervertebral foramen. A total of 34 consecutive patients (19 male, 15 female) with cervical dumbbell neuromas reviewed retrospectively between April 2008 and May 2020. Sixteen tumors were found in the intervertebral foramen of C1-C3, four in C3-C4, and 14 in C4-T1. The approach in all cases was to expose the tumors by intermuscular dissection and to remove them through the enlarged intervertebral foramen without excision of any bony structures. However, to expose tumors at different locations, the incisions shall be made accordingly. In this case series, the incisions were made along the posterior border of the sternocleidomastoid muscle for the C1-C3 tumors and along the anterior border of the muscle for the C3-C4 tumors. Transverse incisions were required for the C4-T1 tumors. Following the mentioned incising approach, all 34 tumors were completely exposed. 31 were completely removed in one stage, and 3 tumors underwent subtotal resection because of brachial plexus nerve adhesion. The vertebral artery and spinal cord were undamaged for all cases. The patients who had total tumor resection showed no sign of recurrence on enhanced magnetic resonance imaging during follow-ups. The status of patients who underwent subtotal resection was stable after radiation therapy. None of the patients developed spinal instability. Cervical dumbbell neuromas can be exposed and removed through the enlarged intervertebral foramen without causing spinal instability or injury to the spinal cord or vertebral artery. This operative approach can retain the integrity of the structures of spine and should be considered the ideal approach for cervical dumbbell neuromas.

Overview of the Cardiac Conduction System: A Narrative Literature Review

The conduction system of the cardiac initiates and coordinates the electrical signals that cause rhythmic and synchronous contraction of the atria and ventricles. This literature review aims to describe the electrophysiology of the cardiac conduction system. Electrical impulses usually arise in the sinoatrial (SA) node. The SA node is innervated by sympathetic and parasympathetic nerves. Each action potential moves rapidly from cell to cell and through the myocardium of the atria, onto the atrioventricular node (AV node), and causes both atria to contract and begin systole. The AV node, located on the right atrial wall superior to the tricuspid valve and anterior to the coronary sinus ostium, conducts action potentials into the ventricles. From the AV node, the conducting fibers converge to form the bundle of His (atrioventricular bundle) within the posterior border of the interventricular septum.

Histologic evidence of brachial plexus compression sites at the thoracic inlet and variations in formation of the lower trunk in cadavers.

In thoracic "outlet" syndrome (TOS), pathologic evidence is well documented for vascular but not neurologic compression. We hypothesized that histologic evidence of compression would be identified at sites where the upper trunk was impacted by the anterior scalene muscle and the lower trunk by anatomic anomalies or the first rib. The purpose of this study was to investigate this hypothesis in human cadavers. Twenty-five cadavers' brachial plexuses were dissected and excised. Histologic and descriptive analysis was directed at juncture 1, the upper trunk and anterior scalene muscle, and juncture 2, C8 and T1 nerve roots (lower trunk) with the posterior border of the first rib. Measurements were obtained at the juncture of the T1 nerve root with the C8 nerve root in relationship to the first rib. Histologic analysis demonstrated epineurial and perineurial fibrosis, myelin thinning, and Renaut bodies at junctures 1 and 2. Lower trunk formation occurred on or lateral to the first rib in 66% of specimens, with asymmetry in 32% of cadavers. A muscle of Albinus was present in 18% of cadavers. A large dorsal scapular artery coursed through 36% of plexuses with a high, arched subclavian artery. We report histologic changes consistent with chronic compression of the upper and lower plexus in the thoracic inlet at hypothesized sites of brachial plexus compression that may correlate with clinical neck/shoulder (upper trunk) and "ulnar nervelike" (C8-T1/lower trunk) symptoms. Anatomic anomalies identified should alert the surgeon to variations of lower trunk formation at compression sites.

Topographic analysis of mandibular ramus zone and anesthetic technique optimizing device

This is a study on the topographic relationship between the final extremity of the lingula of the mandible and the anterior and posterior borders of the ramus of the mandible. This work proposes the creation of a device which directs the positioning of the syringe cartridge + needle assembly, optimizing the execution of the anesthetic technique for blocking the inferior alveolar nerve. Thirty macerated adult mandibles were used, in which two measurements were obtained with the aid of a digital caliper: 1- distance between the anterior border of the mandibular ramus and the final extremity of the lingula; 2- distance between the final extremity of the lingula and the posterior border of the mandibular ramus. Photographs of the mandibles were analyzed on a computer, calculating the angle formed between three points: (1) the anterior border of the mandibular ramus – A point; (2) the anterior point between the inferior premolars of the opposite antimere – P point and (3) the final extremity of the lingula – L point. For the right antimere, 33.33% of the angles found were within the range of 6°-7°, and 23.33% between 9°-10°. As for the left, 30.00% were in the range between 5°-6°, and 23.33% between 7°-8°. It can be concluded that in more than 50% of the analyses, the formed angle varies predominantly between 5° and 10°, therefore, the proposed device will be able to minimize the chances of technical errors and optimize the success for the inferior alveolar nerve block.

Is posterior knee arthroscopy using posterior portals necessary for orthopedic surgeons? The latest evidence on applications and techniques.

Various uses of posterior knee arthroscopy have been shown, including all-inside repair of posterior meniscal lesions, posterior cruciate ligament (PCL) reconstruction or PCL avulsion fixation, extensile posterior knee synovectomy for pigmented villonodular synovitis or synovial chondromatosis, posterior capsular release in the setting of knee flexion contractures, and loose bodies removal. Posterior arthroscopy provides direct access to the posterior meniscal borders for adequate abrasion and fibrous tissue removal. This direct view of the knee posterior structures enables the surgeon to create a stronger biomechanical repair using vertical mattress sutures. During PCL reconstruction, posterior arthroscopy gives the surgeon proper double access to the tibial insertion site, which can result in less acute curve angles and the creation of a more anatomic tibial tunnel. Moreover, it gives the best opportunity to preserve the PCL remnant. Arthroscopic PCL avulsion fixation is more time-consuming with a larger cost burden compared to open approaches, but in the case of other concomitant intra-articular injuries, it may lead to a better chance of a return to pre-injury activities. The high learning curve and overcaution of neuromuscular injury have discouraged surgeons from practicing posterior knee arthroscopy using posterior portals. Evidence for using posterior portals by experienced surgeons suggests fewer complications. The evidence suggests toward learning posterior knee arthroscopy, and this technique must be part of the education about arthroscopy. In today's professional sports world, where the quick and complete return of athletes to their professional activities is irreplaceable, the use of posterior knee arthroscopy is necessary.

Microneurosurgical Anatomic Study of the Horizontal Fissure of the Cerebellum.

The horizontal fissure of the cerebellum, which is the largest and most prominent fissure, has received less interest from anatomists and neurosurgeons. Hence, the current study aims to provide comprehensive detail about the horizontal fissure and its anatomic and surgical relationship with deeper structures such as the dentate nucleus and middle cerebellar peduncle for the benefit of the neurosurgeon. Ten whole formalin-fixed human cadaveric cerebellar hemispheres were obtained from human cadavers donated to the institution. Different parameters of the horizontal fissure were studied, such as length, depth (medial end, lateral end, and middle), sulcal and gyral variations (superficial and deep), and its close relationship, especially at depth, with the dentate nucleus and middle cerebellar peduncle. The total length of the horizontal fissure on the right and the left side was 64.3 ± 7.9 mm (range, 53-77 mm) and 65.6 ± 8.01 mm (range, 53-79 mm), respectively. The medial third of the horizontal fissure, with the fewest vessels, was the most suitable place to puncture or start the dissection of the horizontal fissure. The surface projection of the center of the posterior border of the dentate nucleus lies within 20-21 mm on either side of the posterior midline along the horizontal fissure and is only approximately 4 mm deep from the horizontal fissure. The anatomic measurements and relationships provided in this description of the horizontal fissure will serve as a tool for surgery selection and planning, as well as an aid to improve microneurosurgical techniques, with the final goal being better patient outcomes.

Corrigendum

Corrigendum

A new posterosuperior screw placement strategy to avoid in-out-in screws in femoral neck fractures.

The inverted triangle configuration of the three cannulated screws is the classic fixation method most commonly performed for undisplaced femoral neck fractures in young and geriatric patients. However, the posterosuperior screw has a high incidence of cortical breach, known as an in-out-in (IOI) screw. In this study, we present a novel posterosuperior screw placement strategy to prevent the screw from becoming IOI. Using computed tomography data and image-processing software, 91 undisplaced femoral neck fractures were reconstructed. The anteroposterior (AP), lateral, and axial radiographs were simulated. To simulate the intraoperative screw placement process, participants used three screw insertion angles (0°, 10°, and 20°) to place the screw on the AP and lateral views of the radiograph according to the three established strategies. On the AP radiograph, a screw was placed abutting (strategy 1), 3.25 mm away from (strategy 2), or 6.5 mm away from (strategy 3) the superior border of the femoral neck. On the lateral radiograph, all the screws were placed abutting the posterior border of the femoral neck. Axial radiographs were used to evaluate the screw position. In strategy 1, all the placed screws were IOI regardless of the screw insertion angle. In strategy 2, 48.3% (44/91) of IOI screws occurred at a 0° screw insertion angle, 41.7% (38/91) of IOI screws occurred at a 10° screw insertion angle, and 42.9% (39/91) of IOI screws occurred at a 20° screw insertion angle situation. In strategy 3, no IOI screw occurred, and the screw insertion angles did not affect the safety and accuracy of screw placement. Screws placed according to strategy 3 are safe. The reliability of this screw placement strategy is unaffected by a screw insertion angle of less than 20 degrees.

Computed tomography‐based morphological analysis for intraoral vertical ramus osteotomy in patients with mandibular prognathism

AbstractAimIntraoral vertical ramus osteotomy (IVRO) is an orthognathic surgery for patients with jaw deformity. To avoid complications associated with IVRO, understanding the position of the mandibular foramen and shape of the mandibular ramus in patients with mandibular prognathism is important, which only few studies have reported. Most studies have been performed with dry skulls of older people without jaw deformity. This study aimed to examine the position and shape of the mandibular foramen and ramus, respectively, using computed tomography in patients with mandibular prognathism.MethodsThe study was performed on 50 Japanese patients who underwent IVRO. We examined the position of the mandibular foramen against the occlusal plane, distance between the posterior border of the mandible and mandibular foramen, and thickness of the mandibular ramus.ResultsThe mandibular foramen was vertically located above the occlusal plane at a distance of 2.6 ± 5.1 and 1.2 ± 5.1 mm in men and women, respectively. The distances between the mandibular ramus and foramen, measured with the posterior border line of the mandibular ramus as a criterion, were 15.9 ± 2.2 and 14.4 ± 2.1 mm in men and women, respectively. The thickest parts of the mandibular ramus were 6.8 ± 1.6 and 6.9 ± 0.9 mm in men and women, respectively.ConclusionKnowledge of the accurate position of the mandibular foramen is important for a safe IVRO. Mandibular ramus osteotomy line should be within 10 mm from the posterior border of the mandibular ramus, to avoid inferior alveolar nerve damage.

Identifying safety zone of invasive procedures in the sternocleidomastoid muscle using ultrasonography.

Dysfunctions of the sternocleidomastoid (SCM) muscle, such as myofascial syndrome, torticollis, and cervical dystonia, have been treated using several invasive procedures. In such situations, it is possible to injure the adjacent nerves. This study aimed to demonstrate the course of these nerves in healthy volunteers using ultrasound. The great auricular nerve (GAN), spinal accessory nerve (SAN), transverse cervical nerve (TCN), and supraclavicular nerve (SCN) were scanned by ultrasonography in 26 healthy volunteers. The neck was scanned in the supine position with the head turned 45° to the contralateral side. The cervical plexus was detected in half of the SCM muscle. Each nerve was then traced to the level of contact with the anterior border of the SCM muscle. The following features of the nerves were recorded bilaterally: vertical and horizontal positions of each nerve at the posterior border of the SCM and the cross-sectional area and depth of each nerve at the reference line and anterior border of the SCM. The mean proportions of GAN, SAN, TCN, and SCN were 26%, 26%, 48%, and 80%, respectively near the posterior border, whereas they were 18%, 23%, and 51% for GAN, SAN, and TCN, respectively, at the level of the reference line. Notably, SCN was not visible at the level of the reference line. The mean TCN proportion was 47% at the anterior border of the SCM. The precise location of the nerves and their relationship with the SCM muscle should be considered during invasive procedures. It is recommended that the procedure be performed in the lower half of the SCM muscle, which refers to 50 to 80% of the proportions in our study.