Subcutaneous Fat Thickness Remarkably Influences Contact Pressure and Load Distribution of Buttock in Seated Posture

Spinal cord injury patients are prone to develop deep tissue injury (DTI) as they may spend half their time per day in sitting postures, which produce excessive load in their buttocks. However, the impact of fat thickness on the biomechanical response of buttock in sitting posture remained unclear. This study aimed to investigate the influence of subcutaneous fat thickness on the interface pressure and load distribution of buttock of seated humans. To achieve this goal, a 3-dimensional finite element model of male buttock was constructed and the contact pressure on a rigid cushion was evaluated against experimental results. The modified models, which had various fat thicknesses under ischial tuberosity, were built and used to simulate the sitting conditions with different cushion stiffnesses. In the models simulating sitting on the rigid cushion, the peak contact pressure ranges from 0.052 MPa to 0.149 MPa. In the simulation of sitting on the soft cushion, the peak stress of muscle underneath ischial tuberosity in the model with the thickest fat tissue was slightly higher than that of the other models. The results demonstrate that the fat tissue in the buttock could reduce the contact pressure when sitting on the rigid seat. However, contact pressure solely could not be used to estimate the internal tissue stress of seated buttock, especially in subjects with thicker fat tissue.

Analysis of Body-Slip and Buttock Pressure Characteristics during Operation of a Double-Sliding Reclining Wheelchair in Patients with Spinal Cord Injury

To minimize body collapse due to repetitive reclining and repositioning when using a reclining wheelchair, reclining wheelchairs with a sliding backrest function have been developed. This study compared the differences in body-slip and buttock pressure according to the presence or absence of the sliding function of the backrest during reclining and repositioning motions in 10 patients with spinal cord injury. When reclining from 100° to 130°, backrest sliding and total body-slip in the double-sliding wheelchair were significantly decreased by 21.4 mm and 16.4 mm, respectively, compared to a non-sliding wheelchair, and the peak pressure on the ischial tuberosity was significantly decreased by 8.7 kPa. Upon comparison of the buttock pressure between the initial upright position before reclining and the return upright position after repositioning, the force and mean pressure with the double-sliding wheelchair were significantly reduced compared with those with the non-sliding wheelchair. It was confirmed that the double-sliding system improved body-slip and buttock pressure more effectively than the non-sliding system. This study’s results are expected to provide the basic data necessary for the prescription and selection of wheelchairs in clinical practice and to be utilized in the development of related devices.

Inferior gluteal pain with sitting, unrelated to ischial bursitis

A 64-year-old woman presented to an academic medical centre with postoperative left ischial pain following a left total hip replacement. Her pain was exacerbated by sitting down and with forward flexion of the spine, and the pain radiated from the left ischial tuberosity to the left perineum, groin and medial thigh. An ischial bursa injection was performed, but only resulted in 1 day of excellent pain relief. A diagnosis of inferior cluneal neuralgia was then made. Subsequent inferior cluneal nerve radiofrequency ablation was performed, and provided sustained 50% relief in pain. The patient had a concomitant sensation of ‘ball like’ pressure at her rectum which was determined to be due to levator ani syndrome. She was prescribed pelvic floor physical therapy and botulinum toxin injection, which resulted in further notable improvement of her symptoms.

The Course and Anatomical Characteristics of Sciatic and Femoral Nerves in Unilateral Crowe Type IV Hip Dysplasia

Background This study aims to investigate the course and anatomical characteristics of sciatic and femoral nerves in unilateral Crowe type IV developmental dysplasia of the hip (DDH) patients. Methods We conducted a retrospective own-control study of patients with unilateral Crowe type IV DDH. Bilateral hips’ CTs of 21 female patients were reviewed in our institute from February 2018 to February 2020. The distances between nerves and bony landmarks were measured in different CT sections (anterior superior iliac spine, acetabular inner wall, teardrop, and ischial tuberosity) to analyze the anatomical position and course of sciatic and femoral nerves between bilateral hips. Results In the section of acetabular inner wall, the distance between femoral nerve and acetabular anterior wall in affected hip (13.20±3.59 mm) was significantly smaller than that in healthy hip (16.58±5.12mm) (p=0.000). In other sections, the distances between nerves and bony landmarks in affected hips were significantly larger than or equal to those in healthy hips. Conclusion In female patients with unilateral Crowe type IV DDH, the femoral nerve in affected hip runs closer to anterior acetabular wall than that in healthy hip.

Changes in external ischial tuberosity width at varying trunk–thigh angles between sexes using two measurement methods

This study examined the influence of two methods and various trunk–thigh (TT) angles on external ischial tuberosity width (EITW) for 45 men and 45 women. In the experiment, the impress and seat pressure methods were applied at TT angles of 60°, 75°, 90°, and 105°. When the impress method was used, EITW remained highly consistent across the four measured TT angles with differences of 2.8 and 2.1 mm for men and women, respectively. Conversely, in the seated pressure method, EITW increased with TT angle such that differences in EITW across a full TT angle range were 11.5 and 11.7 mm for men and women, respectively. Irrespective of method, differences in EITW between genders measured approximately 12.6–13.7 mm across all TT angles. Correlation analyses revealed that hip circumference was positively related to EITW in all cases, whereas the relationship of hip width and depth with EITW varied by method and gender. Because of inherent differences in EITW between genders, these findings suggest that gender variability should be considered in seat cushion design.

My Hips Hurt: An Unusual Presentation of Bilateral Groin Pain in an Adolescent Boy

Van Neck-Odelberg disease (VND) is a rare benign pediatric skeletal abnormality characterized by hyperostosis of the ischiopubic synchondrosis (IPS) and clinical symptoms.1,2,3 IPS is a strip of cartilaginous tissue between the superomedial pubic and posterolateral ischial ossification centers, which develops into the inferior pubic rami and ischial tuberosity, respectively.

Key Components Related to Pressure Injury Formation: An Initial Investigation Into Pressure Distribution and Blood Perfusion Responses in Wheelchair Users

Soft tissue around bony prominences in the buttocks and back are high risk areas prone to the development of pressure injuries. From a clinical perspective, prevention of pressure injuries all together is the ideal situation. Unfortunately, prevalence rates still reach 47% with recurrence rates even higher. The goals of this study were to evaluate the effects of a series of wheelchair movements, some that currently exist in commercial wheelchairs and some new, on interface pressures and perfusion under the buttocks. 27 chair positions were obtained by varying back recline, seat pan tilt, and articulation of two supports along the back. Although back recline is commonly taught by therapists to be used as a pressure relieving posture, results indicated an increase in pressures under the ischial tuberosities and sacral areas in reclined positions. Articulation of the back supports produced changes in posture moving from an "erect" to "slouched" position. These movements successfully shifted pressures across back regions. Seat pan tilt was effective in shifting pressures off the ischial tuberosity regions. Additionally, in a portion of the participants, seat pan tilt consistently increased perfusion under the ischial tuberosity region. The findings of this research suggest that movements other than back recline should be considered to more effectively alter interface pressures, particularly in high-risk regions like the sacrum and ischial tuberosities.

THE HYBRID SUBISCHIAL SOCKET FOR PERSONS WITH TRANSFEMORAL AMPUTATION: GAIT PARAMETERS AND CLINICAL ASSESSMENT OF A CASE SERIES

BACKGROUND: The subischial socket interface design is a promising new shape of socket for persons with transfemoral amputation. Typically, the proximal trim line is located distal to the ischial tuberosity, improving comfort in prosthetic users without interfering with gait parameters compared to Ischial Containment Socket (ICS). No studies have investigated the performances of a subischial sockets with suction suspension system. A new subischial socket (Hybrid Subischial Socket - HySS) combined with a hypobaric passive suspension system has been recently developed. OBJECTIVE: To assess the effects of HySS in terms of comfort, hip range-of-motion and gait parameters. METHODOLOGY: Three persons with transfemoral amputation were tested first using their usual ICS and then after one month of continuous use of HySS. FINDINGS: The following parameters improved in all participants using HySS: 1) hip range-of-motion, 2) walking speed and distance, 3) Timed-Up-and-Go-Test time, 4) stride length, 5) double support duration, 6) peak value of hip extension during stance, 7) satisfaction with the prosthesis. CONCLUSION: These findings suggest that the use of HySS could allow improvements for prosthetic use. Layman’s Abstract This case series describes the effects of a subischial socket combined with a hypobaric suction suspension system for persons with transfemoral amputation. This socket has the proximal trim line located distally to the ischial tuberosity and it does not interact with the pelvis. The results have shown that this socket may improve the overall prosthetic comfort, hip range of motion and some gait parameters compared to the conventional ischial containment socket. Article PDF Link: https://jps.library.utoronto.ca/index.php/cpoj/article/view/36252/28095 How To Cite: Pellegrini R, Denza G, Brunelli S, Zenardi D, Imperio M, Vannozzi G, Traballesi M. The hybrid subischial socket for persons with transfemoral amputation: gait parameters and clinical assessment of a case series. Canadian Prosthetics & Orthotics Journal. 2021;Volume 4, Issue 1, No.9. https://doi.org/10.33137/cpoj.v4i1.36252 Corresponding Author: Stefano Brunelli, MDFondazione Santa Lucia, Scientific Institute for Research, Hospitalization and Health Care, Rome, Italy.E-Mail: [email protected] ID: https://orcid.org/0000-0002-5986-1564

CLASSIFYING ISCHIAL TUBEROSITY AVULSION FRACTURES BY OSSIFICATION STAGE AND TENDON ATTACHMENT

Background: Currently, there is no classification system for ischial tuberosity avulsion fractures. Hypothesis/Purpose: To provide a new classification system for ischial tuberosity fractures based on the ossification pattern of the apophysis. Methods: We performed a retrospective records review of patients diagnosed with ischial tuberosity avulsion fractures at our institution from 2008 to 2018. Skeletal maturity (Modified Oxford score [MOS], Risser score), fracture type, size, and displacement were recorded based on initial injury radiographs. We reviewed a large series of pelvic CT and MRI scans from patients aged 10-19 years old to assess the ossification pattern and tendinous attachments of the ischial tuberosity. Pelvic CT review demonstrated a reproducible 5-stage pattern of ossification spanning the age of 13-19 years for males and 12-17 years for females (Figure 1). Review of available CTs and MRIs indicated that the semimembranosus attaches at the most lateral ossification center, followed by the conjoint tendon and adductor magnus as one moves medially (Figures 1). We created a classification system based on location of the ischial tuberosity avulsion fracture: Type 1 (lateral – semimembranosus and conjoint tendons) or Type 2 (complete – semimembranosus, conjoint, and adductor magnus tendons). An A or B descriptor was then added to distinguish minimally displaced (<1 cm) and displaced (≥1 cm) fractures, respectively (Figure 2). Results: We identified 45 ischial tuberosity fractures. Mean age was 14.4 years (range, 10.3–18). Males accounted for 82% of the cohort. Type 1 fractures accounted for 47% of cases and 53% were classified as Type 2. Type 1 fractures were associated with younger age chronological age (p=0.001), lower MOS (p=0.002), lower Risser score (p=0.002), less displacement (p=0.001), and smaller size (p<0.001), when compared with Type 2 fractures (Table 1). Of the 45 patients, 18 had >6 month follow-up with 56% going on to non-union. Non-union was associated with greater displacement (p=0.016) and size (p=0.027). When comparing union rates by fracture location, 33% of Type 1 fractures progressed to non-union, while 78% percent of Type 2 suffered a non-union; however, this difference did not reach statistical significance (p=0.153) (Table 2). Conclusion: In younger patients (ages 13-15 years), the lateral ossification centers of the ischial tuberosity, at which the hamstrings attach, are at risk for isolated avulsion injury. However, in older patients (16-18 years), coalescence of the hamstring and adductor magnus ossification centers predispose patients to a combined avulsion injury consisting of a larger fragment and with greater displacement. [Figure: see text][Figure: see text][Table: see text][Table: see text]