Ischial Tuberosity Research Articles

Tissue Oxygenation in Individuals with Spinal Cord Injury: A Pilot Study.

Pressure injuries (PI) are debilitating tissue lesions characterised by slow healing and a high risk of severe infection. These injuries result from continued tissue hypoxia, or low tissue oxygen saturation (StO2), which is a consequence of impaired blood circulation caused by continued pressure against tissue. PI result in significant suffering and a substantial financial burden. Therefore, we aim to develop an effective preventive measure. Persons with spinal cord injury (SCI) are at a high risk for PI due to their impaired mobility and lack of sensation to alert them to danger. The aim was to test the feasibility of an alert system based on StO2 monitoring in persons with SCI using a novel textile-based near-infrared spectroscopy (NIRS) sensor.Sensors consisted of two emission and two detection points, each point comprising eight fibres each with three light-coupling bends. Textile integration of fibres was achieved by stitching on a mass-production stitching machine. Emission fibres were connected to LEDs of 740 nm and 810 nm. Detection fibres were connected to avalanche photodiodes. Sensors were attached to the skin in the high-PI-risk buttocks area covering the bony prominences of the ischial tuberosity. StO2 was measured in three healthy subjects and two subjects with SCI during repeated sitting and pressure recovery phases.Our experiments showed decreases in StO2 in both groups during sitting phases: during low-pressure sitting phases, StO2 decreased on average -0.32%/min in the healthy subjects and at -1.24%/min in the SCI subjects. During high-pressure sitting, these rates increased to -1.16%/min for the healthy subjects and -2.16%/min for the SCI subjects. During recovery phases, StO2 returned towards normal values, but did not always reach the initial baseline. No discomfort or skin irritation was observed.These first measurements show physiologically reasonable StO2 values and demonstrate sufficient comfort while sitting on a sensor with no skin irritation or other adverse effects of sitting on the sensor for over 30 min. The nurses involved were satisfied with the easy-of-use, materials used, and patient safety demonstrated during the study. These results show that it is feasible to develop an alert system for PI prevention using a safe, wearable, textile-based NIRS sensor.

In vivo strain measurements in the human buttock during sitting using MR-based digital volume correlation

Advancements in systems for prevention and management of pressure ulcers require a more detailed understanding of the complex response of soft tissues to compressive loads. This study aimed at quantifying the progressive deformation of the buttock based on 3D measurements of soft tissue displacements from MR scans of 10 healthy subjects in a semi-recumbent position. Measurements were obtained using digital volume correlation (DVC) and released as a public dataset. A first parametric optimisation of the global registration step aimed at aligning skeletal elements showed acceptable values of Dice coefficient (around 80%). A second parametric optimisation on the deformable registration method showed errors of 0.99mm and 1.78mm against two simulated fields with magnitude 7.30±3.15mm and 19.37±9.58mm, respectively, generated with a finite element model of the buttock under sitting loads. Measurements allowed the quantification of the slide of the gluteus maximus away from the ischial tuberosity (IT, average 13.74 mm) that was only qualitatively identified in the literature, highlighting the importance of the ischial bursa in allowing sliding. Spatial evolution of the maximus shear strain on a path from the IT to the seating interface showed a peak of compression in the fat, close to the interface with the muscle. Obtained peak values were above the proposed damage threshold in the literature. Results in the study showed the complexity of the deformation of the soft tissues in the buttock and the need for further investigations aimed at isolating factors such as tissue geometry, duration and extent of load, sitting posture and tissue properties.

Assessment in location of sciatic nerve between the ischial tuberosity and the greater trochanter of the femur: A cadaveric study

BackgroundThe location description of the sciatic nerve (SN) of adult between the ischial tuberosity (IT) and the greater trochanter of the femur (GT) is inconsistent in publications, this impels us to investigate and measure the distance relationship with SN between IT and GT. MethodsThirty-one adult cadavers were dissected to investigate the distance relationship of SN with the posterior prominent position of the ischial tuberosity (ppIT), the medial edge of IT (mIT) and the lateral prominent position of GT (lGT). ResultsSN passed through the point of the junction of medial one-third and middle one-third of a length from ppIT to lGT, and the midpoint of a length from mIT to lGT from the average data of the total studied cadavers. From average data of female and male, the left SN passed through the point of the junction of the medial two-fifths and the lateral three-fifths of the length between mIT and lGT. Between ppIT and lGT, SN located in a range of proportions from 0.1 to 0.6 from medial to lateral. Between mIT and lGT, SN located in a range of proportions from 0.2 to 0.7 from medial to lateral and all SN passed through the middle third of the length. ConclusionsDifferent bony landmarks draw different location descriptions of anatomic structure. In anatomic study and clinical practice, the utilized bony landmark should be clearly and accurately identified the reference point, inaccurate bony landmark can result in erroneous localization of the interested anatomic structure and lead to operation failure or iatrogenic injury.

Unveiling the common loci for six body measurement traits in Chinese Wenshan cattle

Introduction: Body measurement traits are integral in cattle production, serving as pivotal criteria for breeding selection. Wenshan cattle, a local breed in China’s Yunnan province, exhibit remarkable genetic diversity. However, the molecular mechanisms regulating body measurement traits in Wenshan cattle remain unexplored.Methods: In this study, we performed a genome-wide association method to identify genetic architecture for body height body length hip height back height (BAH), waist height and ischial tuberosity height using the Bovine 50 K single nucleotide polymorphism Array in 1060 Wenshan cattles.Results: This analysis reveals 8 significant SNPs identified through the mixed linear model (MLM), with 6 SNPs are associated with multiple traits and 4 SNPs are associated with all 6 traits. Furthermore, we pinpoint 21 candidate genes located in proximity to or within these significant SNPs. Among them, Scarb1, acetoacetyl-CoA synthetase and HIVEP3 were implicated in bone formation and rarely encountered in livestock body measurement traits, emerge as potential candidate genes regulating body measurement traits in Wenshan cattle.Discussion: This investigation provides valuable insights into the genetic mechanisms underpinning body measurement traits in this unique cattle breed, paving the way for further research in this domain.

Repair of Retracted Hamstring Tears with Hamstring Pulley Technique and Inferomedial Portal

Endoscopic repair of hamstring tears is well described in the literature, but endoscopic management for significantly retracted hamstring tears is not well described. Currently, repairing a hamstring tendon that has retracted 8 cm or more from the footprint on the ischial tuberosity is performed as an open procedure. The technique described here details endoscopic repair of retracted hamstring tears using a suture pulley mechanism and an inferomedial portal.

QUANTITATIVE ULTRASOUND AND MRI IMAGING OF THE BUTTOCKS AND THIGHS IN A SEATED POSITION

Pressure ulcers are a common occurrence in individuals with spinal cord injuries, and are attributed to prolonged sitting and limited mobility. This therefore creates the need to better understand soft tissue composition, in the attempt to prevent and treat pressure ulcers. In this study, novel approaches to imaging the soft tissue of the buttocks were investigated in the loaded and unloaded position using ultrasound (US) and magnetic resonance imaging (MRI).Twenty-six able-bodied participants (n=26, 13 males and 13 females) were recruited for this study and 1 male with a spinal cord injury. Two visits using US were required, as well as one MRI visit to evaluate soft tissue thickness and composition. US Imaging for the loaded conditions was performed using an innovative chair which allowed image acquisition in the seated upright position and MRI was done in the lateral decubitus position and loading was applied to the buttocks using a newly developed MRI compatible loader. The unloaded condition was a lateral decubitus position. Soft tissue was measured between the peak of the ischial tuberosity (IT) and the proximal femur and skin.Tissue thickness reliability for US was excellent, ICC=0.934–0.981 with no significant differences between the scan days. US and MRI measures of tissue thickness were significantly correlated (r=0.68–0.91). US underestimated unloaded tissue thicknesses with a mean bias of 0.39 – 0.56 for total tissue and muscle + tendon thickness. When the buttocks were loaded, total tissue thickness was reduced by 64.2±9.1%.US assessment of soft tissue thicknesses was reliable in both positions. The unloaded measurements using US were validated with MRI with acceptable limits of agreement, albeit tended to underestimate tissue thickness. Tissue thickness, but not fatty infiltration of muscle played a role in how the soft tissue of the buttocks responded to loading.

Body measures, growth curves and body weight prevision of alpacas (Vicugna pacos) reared in Italy

Alpacas represent an exotic species for Italy, introduced no more than 20–30 years ago. Nevertheless, they are currently the most widespread camelid species reared in this country, highlighting the growing interest in breeding this species. So, it is useful to assess parameters on their growth in relation to the new environment. Thus, body weight and body measures were recorded on 49 healthy alpacas of Huacaya type (27 females, 22 males), along a period of 27 months. Overall, 111 individual observations were made. Data were analysed by ANOVA, as growth curves were estimated by applying the Gompertz’s model. Multiple regression was finally used to estimate body weight from body measures. Body weight and linear measures, except for the distance between iliac crest and the length of the rump, were influenced by the category (calves, yearlings, adults) and by the age class within category (p < 0.05), while gender and interaction between gender and category were never significant (p > 0.05). Asymptotic weigh of males was 8.25% higher than females (p < 0.05). Moreover, males at maturity had higher withers (+0.96%), longer body (+2.70%) and chest measurements (+3.18%) than females. Asymptotic rump width (both at the ilium and at the ischium) was higher in females (respectively + 6.19%; +12.90%). According to our work, the best equation for the estimate of body weight from body measures was the following: 5.691 + 0.00005624 * chest circumference3 + 0.00002298 * trunk length3 − 1.155 * rump width between ischial tuberosities + 0.00001545 * height at rump3 (R2=0.957; SE of estimate = 4.36 kg), that is important for a better management of the species.

The Anatomical Course of the Superior Gluteal Vessel Bundle with Regard to Different Approaches in Total Hip Arthroplasty

BackgroundIatrogenic vascular injury during total hip arthroplasty (THA) is rare, reported at rates of 0.05 to 0.3%, but a potentially limb-threatening and life-threatening complication. We aimed to describe safe and danger zones for the superior gluteal vessel bundle (SGV bundle) with reference to different THA approaches. MethodsThere were 27 formalin-fixed cadavers with 49 hemipelves dissected. The course and distribution of the SGV bundle were investigated with the help of anatomical landmarks like the greater trochanter, the iliac tubercle (IT), and the ischial tuberosity. ResultsWe found and exposed the SGV bundle in all 49 specimens with no sex-specific differences. No SGV bundle was encountered up to 28 mm from the greater trochanter and up to 16 mm below the IT. The zone with the highest probability of finding the vessels was 25 to 65 mm below the IT in 39 (80%) cases – defining a danger zone (in relation to the skin incision) in the proximal fourth for the direct anterior approach, in the proximal half for the antero-lateral approach, in the proximal fifth for the direct lateral approach, and almost no danger zone for the posterior approach. ConclusionsSpecial care in proximal instrument placement should be taken during THA. When extending one of the surgical approaches, manipulations in the proximal, cranial surgical window should be performed with the utmost care to avoid SGV bundle injury.

Transperineal Repair of Secondary Perineal Hernia Using a Mesh with a Memory-recoil Ring.

The aim of this study was to evaluate the effectiveness of transperineal repair of secondary perineal hernia (SPH) using a mesh with a memory-recoil ring. Seven patients with SPH who underwent transperineal repair (TPR) between July 2010 and May 2022 were retrospectively analyzed. TPR was performed using a mesh with a memory-recoil ring. All SPHs developed after abdominoperineal resections in patients with anorectal malignancies. The median longitudinal and transverse diameters of the hernia orifice were 8 (7-10) cm and 6 (5-7) cm, respectively. In all cases, the mesh was fixed to the ischial tuberosity, residual levator muscle, coccygeus muscle, and coccyx after thorough dissection of the sac. The median operation time was 154 (142-280) min. Perioperative complications occurred in 2 cases (29%). One was enterotomy, which caused postoperative mesh infection requiring extraction of the mesh. The other was vaginal injury, which resulted in vaginal fistula but closed spontaneously. The median postoperative length of stay was 9 (5-14) days. No recurrence was observed during a median follow-up of 35 (9-151) months. TPR using a mesh with a memory-recoil ring is safe, feasible and promising technique for SPH repairs.

Ischiofemoral Impingement Due to an Undiagnosed Pelvic Avulsion Fracture.

Ischial tuberosity (IT) avulsion fractures are an uncommon cause of injuries in athletes. In this case, a 26-year-old female suffering from posterior right hip pain for over a decade presented with debility and a decrease in athletic function. Notable history included a hamstring strain while sprinting in elementary school. Clinical examination suggested hamstring tendinopathy and ischiofemoral impingement (IFI). Magnetic resonance imaging (MRI) revealed a chronic, fragmented, IT apophyseal avulsion fracture with ischial bursitis and edema within the fragmented bone, suggesting the development of heterotopic ossification (HO). Diagnostic ultrasound revealed signs of IFI, not evident on MRI. Ultrasound-guided corticosteroid injection in her ischial bursa and ischiofemoral space provided complete relief. The patient was able to resume her activities of daily living and sports-related activities without pain. Although interventional treatments may provide temporary pain relief, a multimodal approach is required for the treatment of HO.

A Good Tip-Apex Distance Does Not Make Up For a Poor Reduction in Intertrochanteric Hip Fractures Treated with an Cephalomedullary Nail: The Utility of the Neck-Shaft Angle in Preventing Fixation Failure.

Determine if any fracture characteristics or radiographic parameters were predictive of fixation failure [FF] within 1 year following cephalomedullary nailing for intertrochanteric fractures. A consecutive series of intertrochanteric hip fracture patients (AO/OTA 31A) treated with a cephalomedullary nail were reviewed. Pre-fixation (neck-shaft angle [NSA], distance from ischial tuberosities to greater and lesser trochanters, integrity of lesser trochanter, and fracture angulation) and post-fixation (post-fixation NSA, posteromedial cortex continuity, lag screw position, tip to apex distance [TAD], and post-fixation angulation and translation) radiographic parameters were measured by blinded independent reviewers. The FF and non-FF groups were statistically compared. Logistic regression was performed to determine radiographic parameter correlates of FF. Of 1249 patients, 23 (1.8%) developed FF within 1 year. The FF patients were younger than their non-FF counterparts (77.2 years vs 81.0 years, p=0.048), however there were no other demographic differences. The FF cohort did not differ in frequency of TAD over 25 mm (4.3% vs 9.6%, p=0.624) and had decreased mean TAD (13.6mm vs 16.3mm, p=0.021) relative to the non-FF cohort. The FF cohort had a higher rate of a post-fixation coronal plane NSA more than 10° different from the contralateral side (delta NSA>10°, 34.8% vs 13.7%, p=0.011) with the majority fixed in relative varus. For every 1° increase in varus compared to the contralateral side the odds of FF increased 7% (OR=1.065, 95%CI[1.005-1.130], p=0.034) on univariate analysis. On univariate logistic regression, patients with an absolute post-fixation NSA of 10° or more of varus compared to contralateral were significantly more likely to have a FF (OR=3.139, 95%CI[1.067-8.332], p=0.026). Despite an acceptable TAD, post-fixation NSA in relative varus as compared to the contralateral side was significantly associated with failure in intertrochanteric hip fractures fixed with a cephalomedullary nail. Prognostic Level III.

A novel approach for quantitative imaging of the seated anatomy of the buttocks using ultrasound and MRI

Background: Pressure injuries are commonly noted in individuals who use wheelchairs for mobility and sit for prolonged periods. Understanding soft tissue composition is an essential part of treating and preventing pressure injuries. This study proposes novel approaches for imaging the soft tissue of the buttocks in unloaded and loaded conditions using ultrasound (US) and magnetic resonance imaging (MRI).Methods: The soft tissue of the buttocks was measured in able-bodied participants (n = 26, 50% female) and one male with a spinal cord injury using an innovative chair that allowed seated US acquisition of the buttocks and a newly developed MRI compatible loader. The US test–retest reliability (reproducibility) of buttocks soft tissue was assessed, and US was validated with MRI. Soft tissue was measured between the peak of the ischial tuberosity (IT) and proximal femur and the skin. MRI was used to quantify the fat fraction of the gluteus maximus muscle, with the goal of determining the influence of intramuscular fat on loaded soft tissue responses and was used to assess tissue thickness during buttocks loading.Results: US reproducibility was excellent, ICC = 0.934–0.981, with no statistical differences between scan days. Coefficients of variation (CVs) between visits ranged from 2.5% to 7.4% for loaded and unloaded tissue. US and MRI measures of tissue thickness were significantly correlated (r = 0.68–0.91, p ≤ 0.001). US underestimated the unloaded tissue thicknesses, with a mean bias of 0.39–0.56 cm. When the buttocks were loaded, US- and MRI-measured total tissue thickness was reduced by up to 64.2% ± 9.1% (p &amp;lt; 0.001). The US- and MRI-unloaded total soft tissue of the IT was correlated with loaded tissue thickness (r = 0.54–0.67, p ≤ 0.027). Intramuscular fat of the gluteus maximus was not correlated to changes in muscle thickness with loading (r = 0.05, p &amp;gt; 0.05).Conclusion: We have developed and validated a novel US methodology using MRI as a comparison measure to investigate soft tissue anatomy and deformation during sitting and loading. The ability to obtain such data in the loaded condition is unique and fills an unmet need in understanding loading and pressure injury formation.

Modeling the behavior of the acetabular axis and the axis of the ischial tuberosities during the transition from a standing to a sitting position

Introduction The success of the treatment of patients with degenerative diseases of the spine and concomitant damage to the hip joint depends on the understanding of the biomechanics of movements in the spinal-pelvic segment. After a thorough analysis of the biomechanical processes occurring in the spine-pelvis system during the transition from a standing to a sitting position, it becomes clear that the acetabular axis of rotation of the pelvis in space is not the only one.The purpose of the study was to develop and test a virtual model of the pelvis to study the kinematics of the movement of the spinal-pelvic complex with a description of the emergence of the iscial axis of rotation by changing the position from standing to sitting.Materials and methods The problem was solved using the finite element method. The bones were modeled as absolutely rigid bodies. The main ligaments and muscles were modeled using finite element springs: elastic fragments with specified rheological characteristics. The study of contact interaction was carried out for pairs: "femoral head – acetabulum" and "ischial tuberosities - chair surface".Results A new axis of rotation was revealed, the ischial axis, which corresponded to the points of initial contact of the ischial tuberosities with the surface of the chair. The axis of the acetabulum rotated by 7.1° relative to the ischial axis and at the final moment shifted in the horizontal direction relative to the acetabular axis by 8.83 mm. The gap between the surfaces of the femoral head and the acetabulum was about 8 mm.Discussion The study shows that the pelvis rotates depending on the position around two axes: acetabular and ischial ones, hence it follows that the acetabular axis oscillates back and forth during ante- and retroversion, that is, it is non-static. Shortcomings of the model: 1) muscles and ligaments were modeled using FE springs, the end and beginning of which were set by two points, and the muscles and ligaments in the real body are attached along the entire surface of the bones; 2) soft tissues were not modeled in real volume. The merit of the study is the contact interaction of the pelvis with the chair and its rotation relative to the ischial axis, while other studies consider the rotation of the pelvis only relative to the acetabular axis.Conclusion A new axis of rotation arises due to the contact interaction of the pelvic bone with the surface of the chair when the skeleton moves from a standing position to a sitting position, the ischial axis. The gap between the surfaces of the femoral head and the acetabulum was about 8 mm. It is advisable to conduct a clinical study.

Repair of ischial tuberosity pressure ulcer with a perigluteal muscle flap

Background: Pressure ulcers are caused by long-term pressure on tissues. Hip pressure ulcers are the most common type. Pressure ulcers in the buttocks are classified into three types: sacrococcygeal, ischial tuberosity, and femoral tuberosity. Methods: We used perigluteal muscle tissue flaps to treat nine cases of grade IV pressure ulcers from January 2016 to August 2018. A retrospective study was conducted on all patients who had an ischial tuberosity pressure ulcer repaired with a perigluteal muscle flap. The gluteus maximus myocutaneous flap was combined with the gluteal fasciocutaneous flap, the biceps femoris myocutaneous flap was combined with the gluteal fasciocutaneous flap, the gracilis myocutaneous flap, the biceps femoris myocutaneous flap, and the semitendinosus and semimembranosus myocutaneous flap. Wounds of different sizes and depths were encountered, the details of which are discussed in treatment methods. Data from patients, including age, gender, cause of injury, wound dimensions, the timing of flap coverage, and complications, were analyzed. Results: The appearance of the skin flap was complete after muscular tissue flap repair, with no visible scar hyperplasia. However, after six to 12 months of follow-up, the flap was soft and left a small linear scar. Conclusions: In the repair of an ischial tuberosity pressure ulcer, a peri gluteal muscle flap provides both aesthetic and functional results. Before using muscle tissue flap transplantation, it is recommended to perform multiple debridement + VSD to improve the wound foundation.

Predicting mid-pelvic interspinous distance in women using height and pubic arch angle.

To predict the interspinous distance (ISD) using the relationship between female height and pelvimetric measures on magnetic resonance (MR) images. We obtained measurements of the pubic arch angle (PAA), inlet-anteroposterior (AP) distance, mid-pelvis AP distance, outlet-AP distance, ISD, and ischial tuberosity distance using 710 pelvic MR images from nonpregnant reproductive-aged (21-50 years) women from January 2014 to June 2020. Patient height was also assessed from medical records. We determined the formula for predicting ISD using multiple regression analysis. The mean ± standard deviation of the height, PAA, inlet-AP distance, mid-pelvis AP distance, outlet-AP distance, ISD, and ischial tuberosity distance were 160.0 ± 5.5 cm, 87.31 ± 6.6°, 129.7 ± 9.0 mm, 119.7 ± 8.5 mm, 111.71 ± 8.90 mm, 108.88 ± 8.0 mm, and 121.97 ± 11.8 mm, respectively. Two significant regression formulas for predicting ISD were identified as follows: ISD = 0.24973 × height - 0.06724 × inlet-AP distance + 0.12166 × outlet-AP distance + 0.29233 × ischial tuberosity distance + 0.32524 × PAA (P < 0.001, R2 = 0.9973 [adjusted R2 = 0.9973]) and ISD = 0.40935 × height + 0.49761 × PAA (P < 0.001, R2 = 0.9965 [adjusted R2 = 0.9965]). ISD is the best predictor of obstructed labor. This study predicted ISD with 99% explanatory power using only the height and PAA. The PAA can be measured by transperineal ultrasound. This formula may successfully predict vaginal delivery or cephalopelvic disproportion.

A Dosimetric Correlation Between Radiation Dose to Bone and Reduction of Hemoglobin Levels After Radiation Therapy for Prostate Cancer

The aim of this work was to investigate the correlation between dose to pelvic bone marrow and anemia when treating prostate cancer (PC) with definitive radiation. Patients were selected from a prospective institutional database of patients with PC treated between 2008 and 2021. Pelvic bone (L3/L4 interface through ischial tuberosities) was contoured, and the dose to this structure was calculated. Doses were converted to 2-Gy equivalent doses using an α/β of 10. Exploratory analysis suggested dichotomizing into low-volume exposures of ≤1000 cc (LVE) and high-volume exposures of >1000 cc (HVE). Nonparametric kernel regressions were performed evaluating the effects of time, dose, and androgen deprivation therapy use on hemoglobin (Hgb) values. Reoptimization of plans was performed to evaluate the feasibility of adjusting significant dose levels. A total of 203 patients were included in the final analysis. Median baseline Hgb was 14.9 g/dL (interquartile range, 14.1-15.6). Patients with bone marrow HVE ≥15 Gy were found to have significantly lower predicted Hgb levels compared with those with LVE at day 90: 12.8 g/dL (95% CI, 12.4-13.3) versus 14.5 g/dL (95% CI, 14.0-14.9), respectively (P < .05). When normalizing starting Hgb levels, HVE patients still had significantly lower predicted Hgb levels than LVE at day 90: 86.1% (95% CI, 83.2%-89.7%) versus 96.2% (95% CI, 92.4%-100%), respectively. Reoptimizing 20 plans with high volume of bone marrow receiving 15 Gy resulted in a mean reduction from 1422 cc to 997 cc without compromise of other organs at risk or target coverage. Patients with >1000 cc of bone marrow receiving ≥15 Gy had significantly lower predicted Hgb levels than those with ≤1000 cc. Reoptimization of plans demonstrated that this dose constraint is achievable without impairing plan quality. This dose constraint can be considered to limit acute marrow toxicity in patients with PC.

Research on dynamic comfort maintenance by measuring lower limb edema and seat pressure during simulated seated sleep in flight

Objectives. Seated sleep during flight can bring significant discomfort to passengers. The objective of this research was to study passengers’ dynamic comfort maintenance strategies in lower limb postural shifting during seated sleep in flight. Methods. Studies on seated sleep postures and sitting comfort were conducted. First, 40 participants were recruited to the observational research for collecting typical leg postures during seated sleep. Then, an experiment was conducted with the participants simulating seated sleep in the aircraft seat. The changes in lower limb edema and seat pressure in different postures were measured with a bioelectrical impedance device, near-infrared spectroscopy device and pressure mapping device. Results. Six postures were selected through the observational research. The experiment showed that tissues of the thighs and buttocks suffer alternate higher compression by shifting between the six postures. Lower limb edema is higher when the shanks are forward, while the tissue under the ischial tuberosity suffers higher compression when the shanks are neutral. Conclusion. Six motivations for passengers to shift each sitting posture to achieve dynamic comfort were summarized, which helps obtain alternating rest in different body parts. The suggestion of a leg position adjustment system was also proposed.

Superior Gluteal Nerve Anatomy and Its Injuries: Aiming for a More Secure Surgical Approach of the Pelvic Region.

Because most of the recognized causes of superior gluteal nerve (SGN) injury are iatrogenic, detailed knowledge of the anatomy of the SGN is crucial to prevent its injury associated with surgical procedures. This study aims to describe the precise location of SGN or its branches at the greater sciatic foramen, measure the distances of these neural structures to palpable bony landmarks, and evaluate the possible correlation between these parameters and pelvis size. Twenty human cadaveric hemipelvises were studied. After dissection to expose the SGN or its branches at the greater sciatic foramen, the distances from these neural structures to the greater trochanter (GT), to the anterior superior iliac spine (ASIS), to the posterior superior iliac spine (PSIS), to the ischial tuberosity (IT), and to the greater sciatic notch apex were measured. We found that at the greater sciatic foramen, the SGN emerges as a common trunk in 75% of hemipelvises, and already divided in its superior and inferior branches in 25% of hemipelvises. When the SGN exits the pelvis as a common trunk, it does so, in most cases, in contact with the bone at the apex of the greater sciatic notch or superior to the level of the apex. The median distance from the SGN at the greater sciatic notch to the PSIS, ASIS, GT and IT is 7.6 cm, 10.9 cm, 7.5 cm and 10.8 cm, respectively. We found a positive correlation between some of the analyzed parameters and the size of the pelvis. The anatomical data of this study may serve as pivotal guides during orthopedic pelvic surgery, contributing to minimize SNG iatrogenic lesions with significant implications in the patient's quality of life.

Poster 224: Complications Associated with Proximal Hamstring Tendon Repair: A Systematic Review

Objectives: Proximal hamstring tendon ruptures typically occur as a result of simultaneous hip flexion and knee extension, leading to avulsion of the conjoint and/or semimembranosus tendons from their origin at the ischial tuberosity. Surgical repair of proximal hamstring tendon ruptures has been shown in multiple clinical outcome studies to be superior to nonoperative management, with improved functional scores and ability to return to sport postoperatively. Although several potential complications have been reported in the literature, few studies have comprehensively analyzed the complication profile of proximal hamstring tendon repair. The purpose of this systematic review was to identify the overall rate of complications following proximal hamstring tendon repair, to differentiate these complications into categories, and to compare the complication rates of open versus endoscopic repair. Methods: A systematic review of original research articles was performed using PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. To qualify for study inclusion, included articles were required to be published in English, Level 4 evidence or higher, and had to examine surgical repair of proximal hamstring tendon ruptures. No restrictions were made regarding publication date and methodological quality. Data regarding complications were extracted to calculate the overall complication rate as well as the rate of major and minor complications. A quantitative data synthesis was conducted using Chi-square tests to compare the proportion of patients who experienced complications with endoscopic and open approaches. Results: Forty-three articles including 2,823 proximal hamstring tendon repairs were identified. The overall postoperative complication rate was 15.4% (n = 436). The rate of major complications was 4.6%, including a 0.8% re-rupture rate, 0.8% re-operation rate, 1.7% rate of sciatic nerve injury, 0.9% rate of venous thromboembolism (VTE), and 0.4% rate of deep infection. Minor complications included posterior femoral cutaneous nerve injury (2.4%), persistent sitting pain (2.3%), persistent hamstring myopathy (2.3%), hematoma/seroma (0.8%), peri-incisional numbness (1.8%), and superficial infection (1.1%). Endoscopic proximal hamstring tendon repair was associated with a higher rate of overall complications (p = 0.012), major complications (p = 0.048), and minor complications (p &lt; 0.001) compared to open repair. Conclusions: Proximal hamstring tendon repair is associated with an overall complication rate of 15.4%, including a 4.6% rate of major complications. There was a statistically significant increase in complications for patients treated endoscopically compared to those who underwent an open surgical repair.

Assessing the feasibility of SUVindex (a metric derived from FDG PET/CT) for the diagnosis of polymyalgia rheumatica

To evaluate the feasibility of standard uptake value (SUV) index (ratio lesional maximum SUV [SUVmax] to liver mean SUV [SUVmean]) as a metabolic parameter for diagnosing polymyalgia rheumatica (PMR). A retrospective group of patients with PMR and controls with symptoms similar to PMR but diagnosed with other diseases. Semiquantitative and qualitative analysis of 2-[18F]-fluoro-2-deoxy-d-glucose (18F-FDG) uptake at 18 sites was undertaken for all patients. The diagnostic value of positron-emission tomography/computed tomography (PET/CT) for PMR was assessed by R software using logistic regression and a generalised additive model (GAM). All images were examined independently by two nuclear medicine physicians with extensive work experience. The characteristic sites of PMR were the ischial tuberosity, interspinous bursa, periarticular hip, and symphysis pubis enthesis. The area under the curve (AUC) of the characteristic site SUV index was 0.930, and the best cut-off value was 1.685 with a sensitivity of 84.6% and a specificity of 92.6%. After adjusting for potential confounders, the probability of PMR diagnosis increased as the characteristic site SUV index increased and there was a nonlinear correlation between the two. When the characteristic site SUV index was ≥2.56, the probability of PMR gradually reached the threshold effect, which was as high as 90% or more. The characteristic site SUV index is an independent factor for diagnosing PMR, and PMR should be highly suspected when it is≥1.685. Nonetheless, it is important to note that these findings are based on an initial retrospective single-centre study and require external validation and further prospective evaluation before being translated into clinical practice.