Effect of Peroneus Longus Muscle Release on Abductor Hallucis Muscle Activity and Medial Longitudinal Arch before Toe-Tap Exercise in Participants with Flexible Pes Planus

Pes planus is a medical condition of the foot wherein there is a flattening or lowering of the medial longitudinal arch. The abductor hallucis muscle starts at the heel bone and attaches to the medial side of the first toe. Whenever it contracts, it plays a key role in elevating the medial longitudinal arch. Hence, the abductor hallucis muscle should be strong enough to control the depression on the medial longitudinal arch. The peroneus longus muscle plantarflexes the ankle and everts the ankle and subtalar joint. If this muscle contracts more than the abductor hallucis muscle does, the medial longitudinal arch of the foot is depressed. This study aimed to investigate the effect of myofascial release of the peroneus longus before performing the toe-tap exercise for strengthening the abductor hallucis muscle in participants with flexible pes planus. This cross-over study included 16 volunteers with flexible pes planus. The participants performed a toe-tap exercise before and after the myofascial release of the peroneus longus. During the toe-tap exercise, the muscle activity of the abductor hallucis and peroneus longus were measured using a Delsys Trigno Wireless Electromyography System. The angle of the medial longitudinal arch was measured using Image J software. Photos in the sagittal plane were used. The peroneus longus activity and medial longitudinal arch angles were significantly decreased. On the other hand, the activity of the abductor hallucis significantly increased after the myofascial release of the peroneus longus before performing the toe-tap exercise (p < 0.05). Individuals with flexible pes planus should be encouraged to perform myofascial release of the peroneus longus before the toe-tap exercise to improve the abductor hallucis activity and to elevate the medial longitudinal arch.

Minimum size and positioning of imaging field for CBCT-scans of impacted lower third molars: a retrospective study

Background Cone-beam Computed Tomography (CBCT) is widely used for preoperative 3D imaging of lower third molars. Hence, for this imaging indication, the present study aimed to define the minimum field-of-view (FOV) size and its optimum placement, to decrease radiation exposure, and highlight the need of computer-assisted FOV centering technique for dental CBCT devices. To facilitate proper placement of image field, lower second molar was chosen as reference. Methods The retrospective study included 50 CBCT-scans of 46 patients with mean age of 34 years. Based on the lower second molar, a three-dimensional coordinate was formed and the location of mandibular canal (MC) and the dimensions and locations of the lower third molars, and possible associated pathological findings were assessed. Accordingly, the FOV size and position for third-molar imaging were optimized, while ensuring encompassment of all relevant structures. Results The minimum cylindrical volume, covering lower third molars and MC, was 32.1 (diameter) × 31.6 (height) mm, placed in relation to the second molar crown, top 2.2 mm above cusp tips, anterior edge 6.7 mm in the front of the most distal point of the crown, and lingual edge 7.9 mm on the medial side of the lingual wall. Conclusions The optimized FOV for lower third molars was smaller than common standard small FOVs. We recommend using FOV volume 3.5∅ × 3.5 cm for third molars without associated pathology. Accurate FOV protocols are essential for development of new CBCT-devices with computer-assisted and indication-specific FOV placement.

Establishing the Role of Elbow Muscles by Evaluating Muscle Activation and Co-contraction Levels at Maximal External Rotation in Fastball Pitching

Background: Baseball pitching is associated with a high prevalence of ulnar collateral ligament injuries, potentially due to the high external valgus load on the medial side of the elbow at the instant of maximal shoulder external rotation (MER). In-vitro studies show that external valgus torque is resisted by the ulnar collateral ligament but could also be compensated by elbow muscles. As the potential active contribution of these muscles in counteracting external valgus load during baseball pitching is unknown, the aim of this study is to determine whether and to what extent the elbow muscles are active at and around MER during a fastball pitch in baseball.Methods: Eleven uninjured pitchers threw 15 fastball pitches. Surface electromyography of six muscles crossing the elbow were measured at 2000 Hz. Electromyography signals were normalized to maximal activity values. Co-contraction index (CCI) was calculated between two pairs of the flexor and extensor elbow muscles. Confidence intervals were calculated at the instant of MER. Four ranges of muscle activity were considered; 0–20% was considered low; 21–40% moderate; 41–60% high and over 60% as very high. To determine MER, the pitching motion was captured with a highspeed camera at 240 Hz.Results: The flexor pronator mass, pronator teres, triceps brachii, biceps brachii, extensor supinator mass and anconeus show moderate activity at MER. Considerable variation between participants was found in all muscles. The CCI revealed co-contraction of the two flexor-extensor muscle pairs at MER.Interpretation: The muscle activation of the flexor and pronator muscles at MER indicates a direct contribution of forearm muscles crossing the medial side of the elbow in counteracting the external valgus load during fastball pitching. The activation of both flexor and extensor muscles indicates an in-direct contributory effect as the combined activity of these muscles counteract opening of the humeroulnar joint space. We believe that active muscular contributions counteracting the elbow valgus torque can be presumed to relieve the ulnar collateral ligament from maximal stress and are thus of importance in injury risk assessment in fastball pitching in baseball.

Comment to: The utility of ultrasound examination in cubital tunnel syndrome caused by heterotopic ossification

Ultrasound (US) could visualize the pathological anatomy of HO and the enlargement site and compression location of the nerve in the cubital tunnel [1]. We read with great interest the article of Jačisko et al[2]. In addition, we report rare US images of HO in direct contact with the swollen ulnar nerve in the cubital tunnel that was not detected by plain radiography. A 60-year-old female presented with a six-month history of elbow pain. Her pain was located at the medial side of the right elbow joint and accompanied by numbness of the fifth finger. She had a history of excessive manual labor due to her occupation as a gardener over the past few decades. The numbness began with the fifth finger initially and gradually extended toward the medial side of the elbow joint. US images showed hyperechoic masses causing acoustic shadowing, in direct contact with the ulnar nerve in the cubital tunnel. The HO seems to be related to compression of the ulnar nerve. The ulnar nerve was swollen (Figure 1-a, b). The maximal cross-sectional-area was 0.10 cm2. Plain elbow radiographs demonstrated osteophyte formation in the coronoid process of the ulna, the coronoid fossa of the humerus, and in the radial head (Figure 1-c). Radiographic imaging showed no heterotopic bone formation in the soft tissues surrounding the medial side of the right elbow. We performed US-guided perineural injection with a mixture of 1 cc of 10 mg triamcinolone and 3 cc of 0.2 % ropivacaine. Her pain and numbness gradually diminished with no adverse effects. Her pain reduced by 70% after two weeks, with pain improvement sustained for 6 months after the injection. Jačisko et al[2]have presented some diagnostic US imaging on neuropathy caused by HO located close to the ulnar nerve in the cubital tunnel. Especially, this case showed definite heterotopic bone formation in the soft tissue surrounding the medial side of the elbow on plain radiography. The classic sonographic patterns of HO were defined by the presence of central hypoechoic area surrounded by foci of calcification [3, 4]. The distortion of normal soft tissue and the formation of hypoechoic areas, with or without foci of calcification can also be shown as early signs[3, 4]. The use of US for HO is highly sensitive and provides an earlier diagnosis compared with other radiologic modalities [3-5]. It can be an effective treatment strategy and may improve the prognosis of neuropathy. We highlight that US evaluation can provide early diagnostic information about ulnar nerve morphology and various HO formations even if plane radiographs did not show heterotopic bone formation in the soft tissues surrounding the medial side of the elbow.

Cadaveric Study and Micro-Computed Tomography of the Anatomy of Palatine Aponeurosis and its Link to the Soft Palate Muscles and Pharyngeal Muscles

Objective There have been few studies on the anatomy of palatine aponeurosis (PA). Herein, we elucidated the relationship between the PA and soft palate muscles and pharyngeal muscles. Design Two cadaveric specimens were dissected to observe the gross anatomy of the PA. Six cadaveric specimens were processed and scanned by micro-computed tomography to determine the elaborate anatomy. Images were exported to Mimics software to reconstruct a three-dimensional model. Results The PA covered the anterior (32.1%-38.8%) of the soft palate, extending from the tensor veli palatini (TVP) and connecting to 3 muscles: palatopharyngeus (PP), uvula muscle, and superior pharyngeal constrictor (SC). The SC and PP are attached to the PA on the medial side of the pterygoid hamulus. SC muscle fibers were attached to the hamulus, forming a distinct gap between the hamulus. Some muscle fibers of the PP and uvula originated from the PA. The PA extended from the TVP to the midline and the posterior edge of the hard palate. The PA was not uniformly distributed, which was complementary to the attached muscles in thickness. Conclusions PA, as a flexible fibrous membrane, maintains the shape of the soft palate. It extends from the TVP and covers anteriorly about one-third of the soft palate. The PA provides a platform for the soft palate muscles and pharyngeal muscles, connecting to the PP, uvula muscle, and SC. These muscles are important for palatopharyngeal closure and middle-ear function. It is necessary to minimize the damage to the PA during surgical interventions.

Bacterial Colonization of the Condyle in Patients with Advanced Mandibular Osteoradionecrosis: Analysis of Hemimandibulectomy Specimens

Advanced mandibular osteoradionecrosis (ORN) sometimes requires extended resection (e.g., hemimandibulectomy). Bacterial infection contributes to ORN pathogenesis. To control infection and determine the extent of debridement required, an understanding of bacterial spread within sites of mandibular ORN is important. The current study used a histopathological approach to assess bacterial colonization in the mandibular condyle and elucidate possible paths of bacterial spread towards the mandibular condyle. Four hemimandibulectomy specimens were selected. Areas of bone destruction were macroscopically assessed and confirmed using hematoxylin and eosin staining. Bacterial presence within mandibular condyle was confirmed with Gram staining. Bone exposure was observed in the molar area in all specimens. Macroscopic bone destruction was apparent especially near the medial side of the cortical wall. Gram staining revealed bacterial colonization of the mandibular condyle in three of the four specimens. In conclusion, bacteria tended to spread posteriorly and through the medial side of the mandibular cortical wall. In patients with advanced ORN, the potential for bacterial colonization of the mandibular condyle should be considered during treatment.

Late Developed Unusual Nasal Involvement of Postoperative Maxillary Cyst Following Maxillary Sinus Augmentation: A Case Report

Postoperative maxillary cyst (POMC) is a benign expansive cystic lesion of the maxilla generally related to invasive maxillary surgeries or trauma. POMC can also develop after maxillary sinus augmentation (MSA), but many dentists are not well-aware of such complication of MSA. A 56-year-old male patient had undergone bilateral MSA. After 18 years, the patient reported painless swelling on the left palate. On the panoramic radiographs, no specific findings were found, but a large unilocular lesion was detected at the medial side of the previous augmentation of the left maxillary sinus on cone-beam computed tomographic examination. The lesion expanded medially and downward to destruct the medial wall of the maxillary sinus and palatal bone. Medial expansion of the lesion also reached the nasal septum and inferior meatus. Due to the extent and the location, the lesion was hard to manage using an intraoral surgical approach. The patient was then referred to an otolaryngologist in a university hospital. Endoscopic marsupialization was performed under general anesthesia. Previous augmentation and dental implants could be maintained during the marsupialization. The removed tissue sample revealed respiratory epithelium with inflammatory cell infiltration, confirming that the lesion was a postoperative maxillary cyst (POMC). There has been no recurrence of POMC to date. POMC is a rare postoperative complication of maxillary sinus augmentation, but clinicians should be aware of the possibility of POMC and the necessity of regular radiological monitoring.

Uncovering associations between data-driven learned qMRI biomarkers and chronic pain

Knee pain is the most common and debilitating symptom of knee osteoarthritis (OA). While there is a perceived association between OA imaging biomarkers and pain, there are weak or conflicting findings for this relationship. This study uses Deep Learning (DL) models to elucidate associations between bone shape, cartilage thickness and T2 relaxation times extracted from Magnetic Resonance Images (MRI) and chronic knee pain. Class Activation Maps (Grad-CAM) applied on the trained chronic pain DL models are used to evaluate the locations of features associated with presence and absence of pain. For the cartilage thickness biomarker, the presence of features sensitive for pain presence were generally located in the medial side, while the features specific for pain absence were generally located in the anterior lateral side. This suggests that the association of cartilage thickness and pain varies, requiring a more personalized averaging strategy. We propose a novel DL-guided definition for cartilage thickness spatial averaging based on Grad-CAM weights. We showed a significant improvement modeling chronic knee pain with the inclusion of the novel biomarker definition: likelihood ratio test p-values of 7.01 × 10–33 and 1.93 × 10–14 for DL-guided cartilage thickness averaging for the femur and tibia, respectively, compared to the cartilage thickness compartment averaging.

P132 TRANSABDOMINAL PREPERITONEAL REPAIR (TAPP) FOR DE NOVO TYPE INGUINAL HERNIAS

Aim In Japan, the de novo type inguinal hernia is defined as a hernia that develops without being related to the vaginal process of peritoneum. The pathological condition of a de novo type hernia is considered similar to that of a sliding hernia. the aim of this study is to discuss about the operative procedure for de novo type inguinal hernia, with a particular focus on lipomas. Material and Methods We examined surgical procedures, rate of combined lipoma, postoperative complications, and recurrence rates of de novo cases among TAPP cases performed in our department from 2018 to 2020. Results We performed 230 TAPP repairs during the period, included 56 de novo type hernia. 19 cord lipomas were found in de novo type hernias but none in non de novo type hernias. The lipomas prolapsed from the lateral side of the internal inguinal ring in 6 cases, medial side in 9 cases, In 4 cases, lipoma or lipomatous tissue were embedded in the spermatic cord and they could not be extracted. There were no postoperative complications. The average postoperative hospital stay was 1.2 days. There were no chronic pain nor recurrence. Conclusions It is important to note that the de novo hernia is associated with a high incidence of lipoma. Since lipomas are often attached to the peritoneum, dissecting the peritoneum at the internal inguinal ring has the risk of missing the presence of lipomas, and in de novo hernias, the peritoneum must be pulled out.

Development of a Lower Limb Finite Element Musculoskeletal Gait Simulation Framework Driven Solely by Inertial Measurement Unit Sensors

Finite element musculoskeletal (FEMS) approaches using concurrent musculoskeletal and finite element models driven by motion data such as marker-based motion trajectory can provide insight into the interactions between the knee joint secondary kinematics, contact mechanics, and muscle forces in subject-specific biomechanical investigations. However, these data-driven FEMS systems have a major disadvantage that makes them challenging to apply in clinical environments, i.e., they require expensive and inconvenient equipment for data acquisition. In this study, we developed an FEMS model of the lower limb driven solely by inertial measurement unit sensors that include the tissue geometries of the entire knee joint, and that combine modeling of 16 muscles into a single framework. The model requires only the angular velocities and accelerations measured by the sensors as input. The target outputs (knee contact mechanics, secondary kinematics, and muscle forces) are predicted from the convergence results of iterative calculations of muscle force optimization and knee contact mechanics. To evaluate its accuracy, the model was compared with in vivo experimental data during gait. The maximum contact pressure (11.3 MPa) occurred on the medial side of the cartilage at the maximum loading response. The developed framework combines measurement convenience and accurate modeling, and shows promise for clinical applications aimed at understanding subject-specific biomechanics.