Prosthetic principles in the management of fractures.
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Adult↗
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Results for “Ischium”
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Separation of brachio-thoraco-omphalo-ischiopagus bipus conjoined twins.
Separation of 3-year-old brachio-thoraco-omphalo-ishiopagus bipus conjoined twin girls is reported. Detailed preoperative assessment and a multidisciplinary approach were essential prerequistes to surgery. The difficulties of managing the extensive body wall defect resulting from separation are discussed. Despite the use of subcutaneous and intraperitoneal tissue expanders, a large area of prosthetic material was required to reconstruct the abdominal wall. Skin cover was achieved using a combination of meshed allogeneic skin, homograft split skin, and autologous cultured keratinocytes. One twin died in the early postoperative period, but the other has recovered well and is awaiting further rehabilitative treatment.
Abdominal Muscles↗
Separation of ischiopagus tripus conjoined twins.
The authors report on their second experience of a successful separation of ischiopagus tripus conjoined twins. Particular emphasis is placed on the painful decision of sacrificing the only available leg to cover the infected wound after an unexpected complication in twin A. The twins' preoperative evaluation, separation surgery, and subsequent 16-month course are described.
Humans↗
Imaging of the ischiorectal fossa.
A retrospective evaluation of 500 routine abdominal computed tomography scans revealed 21 cases of ischiorectal fossa disease in 16 patients. Pathologic processes included involvement by primary and secondary neoplasms, usually of gynecologic origin; rectal prolapse; and abscess. These abnormalities can be missed if the ischiorectal fossae are not included in routine abdominal scans. The anatomy of the ischiorectal fossae and their relationship to other pelvic organs are well demonstrated with high-resolution computed tomography scans as well as by magnetic resonance imaging.
Abdomen↗
Prostate motion during standard radiotherapy as assessed by fiducial markers.
From November 1993 to August 1994, 55 patients with localized prostate carcinoma had three gold seeds placed in the prostate under transrectal ultrasound guidance prior to the start of radiotherapy in order to track prostate motion. Patients had a planning CT scan before initial simulation and again at about 40 Gy, just prior to simulation of a field reduction. Seed position relative to fixed bony landmarks (pubic symphysis and both ischial tuberosities) was digitized from each pair of orthogonal films from the initial and boost simulation using the Nucletron brachytherapy planning system. Vector analysis was performed to rule out the possibility of independent seed migration within the prostate between the time of initial and boost simulation. Prostate motion was seen in the posterior (mean: 0.56 cm; SD: 0.41 cm) and inferior directions (mean: 0.59 cm; SD: 0.45 cm). The base of the prostate was displaced more than 1 cm posteriorly in 30% of patients and in 11% in the inferior direction. Prostate position is related to rectal and bladder filling. Distension of these organs displaces the prostate in an anterosuperior direction, with lesser degrees of filling allowing the prostate to move posteriorly and inferiorly. Conformal therapy planning must take this motion into consideration. Changes in prostate position of this magnitude preclude the use of standard margins.
Algorithms↗
Urethrography and ischial intertuberosity line in radiation therapy planning for prostate carcinoma.
We analyzed our urethrography procedure regarding the validity of using the ischial tuberosity line (ITL) as the caudal margin of treatment portals for prostate carcinoma. The distances of the external urethral sphincter and the lowest margin of the opacified urinary bladder were analyzed in one hundred fifteen consecutive urethrograms. None showed the urethral sphincter to be caudal to the ITL. Ten percent of the sphincters were located less than 1.0 cm cephalad to the ITL, yielding inadequate treatment coverage if the ITL was relied on. Arbitrarily considering 2.0 cm or more of the urethral irradiation to be excessive, the use of the ITL would then have resulted in unnecessary normal tissue irradiation of 42.5%. The ITL should not be used as the caudal margin for prostate treatment portals. Variation in sphincter position, as also seen on lateral projections, reveal a need for urethrography as a necessary supplement to computed tomography to plan radiation portals for prostate cancer.
Contrast Media↗
Pathologic fracture after radiation therapy for primary non-Hodgkin's malignant lymphoma of bone.
Between 1963 and 1981, 32 patients with biopsy proven non-Hodgkin's lymphoma involving bone were treated at the Mallinckrodt Institute of Radiology either with radiation alone or in conjunction with chemotherapy. An unexpectedly high rate of fracture at the site of the tumor was observed. Six patients were excluded because they survived less than six months after the completion of radiotherapy or were lost to follow-up within six months. There were 15 appendicular and 17 axial sites treated. Local control was achieved in 30 of 32. There were 10 patients with appendicular lesions of which seven suffered a fracture. Of the seven patients with lesions in a weight bearing bone, six suffered fractures. Twenty-six sites of involvement received less than 5000 rad. Five sites of involvement with diffuse histiocytic lymphoma (DHL) involving the appendicular skeleton received 5000 to 6000 rad. One site with DHL involving the axial skeleton received 5000 rad. Of the six patients receiving high dose, two presented with pathologic fractures of the femur requiring surgical stabilization and the remaining four patients suffered subsequent fractures 7 to 30 months after completion of therapy. Two of these six had local recurrence of disease. It appears that involvement of the appendicular skeleton by lymphoma frequently results in fracture. Doses of 5000 rad or greater do not increase the probability of local control but may contribute to the risk of fracture following radiotherapy.
Adult↗
Large epidermal cyst involving the ischiorectal fossa: MR demonstration.
A large subcutaneous mass was noted in the buttock of a 79-year-old man. Computed tomography (CT) and magnetic resonance imaging (MRI) showed a thin-walled cystic mass that involved the ischiorectal fossa. The content appeared hyperintense on T1-weighted images. T2-weighted images demonstrated a considerable amount of debris. At surgery an epidermal cyst with markedly keratinized squamous epithelium was found. It contained much keratin and cholesterin.
Aged↗
An atrophic, fat-infiltrated gracilis muscle for ischial reconstruction?
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Adult↗
Center of pressure excursion capability in performance of seated lateral-reaching tasks.
BACKGROUND: Seated center of pressure excursion capability can be used for patient evaluation in a clinical setting and in universal design. A quantification of excursion capability across age and anthropometry has not been previously reported, although some research suggests that the ischial tuberosities are the support structure limiting the excursion. METHODS: Thirty-eight neurologically healthy adults ranging in age from 21 to 74 years and including 12 obese persons performed a series of 6 lateral-reaching tasks. Participants sat on a platform such that their feet did not touch the ground, leaving their legs free to provide counterbalancing support. Data recorded from a force plate under the platform allowed calculation of the center of pressure throughout the trial and the maximum excursion for each condition was recorded. FINDINGS: The average excursion capability for the healthy, experimental population was 148 mm or 37% of seated hip breadth. Taller participants had larger maximum excursions, on average, than shorter participants, and older participants had smaller excursions than younger participants. INTERPRETATION: The greater trochanter of the femur-rather than the ischial tuberosities-appears to be the primary support structure limiting center of pressure excursion in lateral, balance-limited reaches without contralateral support. These measures and concepts can be used for design, accommodation, and clinically for patient assessment.
Adult↗
Estimating differences in volumetric flat bone growth in pediatric patients by radiation treatment method.
PURPOSE: To estimate potential differences in volumetric bone growth in children with sarcoma treated with intensity-modulated (IMRT) and conformal (CRT) radiation therapy using an empiric dose-effect model. METHODS AND MATERIALS: A random coefficient model was used to estimate potential volumetric bone growth of 36 pelvic bones (ischiopubis and ilium) from 11 patients 4 years after radiotherapy. The model incorporated patient age, pretreatment bone volume, integral dose >35 Gy, and time since completion of radiation therapy. Three dosimetry plans were entered into the model: the actual CRT/IMRT plan, a nontreated comparable IMRT/CRT plan, and an idealized plan in which dose was delivered only to the planning target volume. The results were compared with modeled normal bone growth. RESULTS: The model predicted that by using the idealized, IMRT, and CRT approaches, patients would maintain 93%, 87%, and 84%, respectively (p = 0.06), of their expected normal growth. Patients older than 10 years would maintain 98% of normal growth, regardless of treatment method. Those younger than 10 years would maintain 87% (idealized), 76% (IMRT), or 70% (CRT) of their expected growth (p = 0.015). Post hoc testing (Tukey) revealed that the CRT and IMRT approaches differed significantly from the idealized one but not from each other. CONCLUSIONS: Dose-effect models facilitate the comparison of treatment methods and potential interventions. Although treatment methods do not alter the growth of flat bones in older pediatric patients, they may significantly impact bone growth in children younger than age 10 years, especially as we move toward techniques with high conformity and sharper dose gradient.
Adolescent↗
Diagnosis and management of posttraumatic piriformis syndrome: a case study.
OBJECTIVE: The aim of this study is to describe the clinical management of a young male patient with sciatica symptoms that developed after an avulsion of the ischial tuberosity. This is a rare injury, but complications may occur. CLINICAL FEATURE: A 19-year-old patient developed sciatica 6 months after a football injury. The patient described his symptoms as a shooting pain from the buttock to the lateral part of the foot, along the back of his thigh and calf, sometimes accompanied by paresthesia. Physical examination showed restricted hip range of motion and a positive Bonnet's test. X-ray analysis revealed a bony overgrowth of the right ischial tuberosity. INTERVENTION AND OUTCOME: A treatment plan was designed to decrease the pain level, increase sacroiliac and lumbar joint mobility, and augment muscular extensibility. The patient received 20 treatments over a period of approximately 3 months. Complete recovery was observed 5 months later. CONCLUSION: Although many differential diagnoses were contemplated, it is most likely that changes in muscular tension and gait pattern, resulting from the ischial tuberosity avulsion, contributed to overuse of the piriformis muscle leading to a piriformis syndrome.
Adult↗
Early total ischiectomy with primary closure for decubitus ulcer.
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Cicatrix↗
Pelvic movement and interface pressure distribution during manual wheelchair propulsion.
OBJECTIVE: To investigate the movement of the ischial tuberosities and the redistribution of interface pressure during manual wheelchair propulsion. DESIGN: Measurement of ischial tuberosity positions and comparison with corresponding position of the zones of peak pressure by using independent samples t tests. Analysis of variance was used to compare peak and average pressures under static and dynamic conditions. SETTING: Human locomotion laboratory. PARTICIPANTS: Ten subjects with spinal cord injury (SCI) and 10 individuals with no disabilities. INTERVENTIONS: Manual wheelchair propulsion on a stationary wheelchair ergometer at the subject's maximum propulsion speed. MAIN OUTCOME MEASURES: Seat interface pressure and the 3-dimensional position of the pelvis were measured with a pressure mat and an optical motion analysis system. RESULTS: During wheelchair sprinting, the ischia were located at 19.2+/-11.7 mm behind the corresponding peak pressure locations. The anteroposterior rocking of the pelvis was 11.2 degrees and 5.2 degrees for the normal and SCI group, respectively. The average interface pressure over the ischial tuberosity area was lower under dynamic conditions. It was also observed in the SCI group that there was a concentration of high-pressure gradients around the peak pressure areas of the buttock during dynamic propulsion. CONCLUSION: Peak pressure locations did not concur exactly with the ischial tuberosities during propulsion. The movements of the ischial bone and the cyclic loading imposed on the tissue underneath the ischial tuberosities during dynamic conditions may have implications for the etiology of decubitus ulcers.
Adult↗
Skin vascular reaction to short durations of normal seating.
The effects of duration and compliance of seating surfaces on reactive hyperemia within the skin overlying the ischial tuberosities was determined in four normal, one paraplegic and one cerebral palsy subject. Reactive hyperemia was demonstrated thermographically after short durations (ie, 5, 10, and 15 minutes) of seating on a hard surface. The magnitude of hyperemic response increased significantly (p < .001 for 15 v 5 minutes; p = .019 for 15 v 10 minutes; p = .001 for 10 v 5 minutes) with increased duration of seating. In all six subjects studied, the maximum postseating blood flow continued to increase with up to 15-minute seating on a hard surface, and the mean maximum response was positively correlated with duration of seating (4 = 0.918, p < 0.001). Although there was good correlations between magnitudes of interface pressures measured and vascular responses within each individual, there was no such direct correlation between individuals.
Adult↗
Posture effect on seating interface biomechanics: comparison between two seating cushions.
OBJECTIVE: This study aimed at investigating the effects of sitting posture on ischial pressure and pelvic orientation for two types of cushions. DESIGN: Two types of seating devices, Roho and Polyurethane (PU) Foam cushions, six predefined postures, and two subject groups, Normal and Paraplegic, were tested. Ischial pressure and pelvic orientation were monitored. The sequence in which the cushions were tested were randomized, and the postures were tested according to a preplanned sequence. SETTING: The experiments were carried out in the laboratory of a rehabilitation engineering centre in Hong Kong. PARTICIPANTS: Six paraplegic subjects (referred sample) and 8 normal volunteers were tested. At the time of study, no subjects showed any signs of pressure sore or other health problems. MAIN OUTCOME MEASURES: It was hypothesized that sitting posture could significantly affect pelvic orientation as well as pressure distribution. It was also hypothesized that cushion selection was a critical factor in compensating the adverse effects of postures on pressure distribution. RESULTS: With the paraplegic group, the maximum ischial pressure recorded on Roho for various postures ranged from 88 mmHg for the Trunk-Bent-Forward (PF) posture to 146 mmHg for the Trunk-Bent-Right (PR) posture, whereas on PU foam cushions, the values ranged from 106 mmHg for the PF posture to 221 mmHg for the PR posture. With the paraplegic subjects sitting with their trunks bent laterally, it was found that the mean pressure difference between the left and right ischial tuberosities was more prominent on the PU foam cushion than on the Roho. CONCLUSION: Sitting posture can significantly affect pelvic orientation and ischial pressure. This study was also showed that the Roho cushion was significantly more efficient in compensating the adverse effects of sitting posture on pressure distribution.
Biomechanical Phenomena↗
Seating pressures with conventional and dynamic wheelchair cushions in tetraplegia.
OBJECTIVE: To compare pressure relief from a dynamic wheelchair cushion to a tilt-in-space wheelchair with conventional cushions. STUDY DESIGN: Repeated measures analysis. SETTING AND SUBJECTS: Spinal cord injury unit; 16 tilt-in-space wheelchair users with motor-complete tetraplegia. MAIN OUTCOME MEASURES: Interface pressure at ischial tuberosities. RESULTS: Mean ischial pressure with subjects seated upright on the dynamic cushion during the low ischial pressure phase was lower than tilted pressure on the gel cushion, but it was not significantly different from tilted pressure on the dry-flotation cushion (dynamic/upright, 71 mm Hg; gel/tilted, 86 mm Hg; dry-flotation/tilted, 74 mm Hg; p<.05 dynamic vs. gel). Mean ischial pressure with subjects upright on the dynamic cushion during the high ischial pressure phase was significantly greater than the gel/upright and dry-flotation/upright conditions (dynamic/upright, 157 mm Hg; gel/upright, 128 mm Hg; dry-flotation/upright, 111 mm Hg; p<.001). CONCLUSION: The dynamic cushion produces similar pressure relief over the ischial tuberosities during the low pressure phase to a tilt-in-space wheelchair and conventional cushions. The dynamic cushion may be an alternative to a tilt-in-space wheelchair for some individuals.
Adult↗
The scrotal flap in ischial decubitus.
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Humans↗