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At least 397 records · Page 22Linked to original sources

Computer aided tumor resection in the pelvis.

Surgical treatment of malignant tumors within the pelvis is a complex problem due to the anatomy and biomechanics. There are standardized preoperative diagnostic tools like computed tomography (CT) or magnetic resonance imaging (MRI) that provide multidimensional information. However, this information cannot be transferred intraoperatively. Computer aided orthopedic surgery (CAOS) may be a solution for precise intraoperative accuracy for these indications. We report on two patients with tumors within the pelvis. In one patient, an infiltrating recurrent chordoma within the sacrum was resected with CAOS. The other patient presented with a periacetabular chondrosarcoma. Resection was done with navigation so precise that a custom-made hemipelvis prosthesis with a special coating fit. In both patients, a complete resection was achieved with tumor-free resection margins. Navigation may be helpful in tumor surgery within the pelvis.

Bone Neoplasms↗

Sexual dimorphism in the human pelvis: testing a new hypothesis.

Sexual dimorphism in the human pelvis is inferentially related to parturition. Investigators disagree about the identification and obstetric significance of pelvic dimorphism. Benefiting from a large sample of complete skeletons from the Coimbra Identified Skeletal Collection, we show that the dimensions of the true pelvis (birth canal) that are most sexually dimorphic (that is, the dimensions of females are greater than males) are those which are related to biparietal deformation, which often leads to the death of the human neonate. These dimensions are: the anteroposterior diameter of the inlet (index of dimorphism = 108.41), the transverse diameter of the bispinous midplane (index of dimorphism = 117.13) and the transverse diameter of the outlet (index of dimorphism = 112.3). Therefore, sexual dimorphism in the human pelvis is a reflection of differential selection on the two sexes. These results may stimulate further studies with a fresh approach regarding the fossil and comparative evidence for when and how the modern pattern of birth has evolved.

Female↗

Squamous cell carcinoma of the renal pelvis: nuclear deoxyribonucleic acid ploidy studied by flow cytometry.

From 1944 to 1987, 28 patients with squamous cell carcinoma of the upper urinary tract were treated and also had tumor specimens that were fully evaluable by flow cytometric nuclear deoxyribonucleic acid ploidy analysis: 22 had squamous cell carcinoma of the intrarenal collecting system, 4 had tumors of the ureter, and 2 had tumors of the renal pelvis and ureter. Eight patients (29%) had deoxyribonucleic acid diploid, 11 (39%) tetraploid and 9 (32%) aneuploid ploidy patterns. Ploidy pattern significantly correlated with histological grade and tumor stage. Almost all tumors were histologically of high grade; among the patients with high grade tumors ploidy analysis separated fair and poor prognosis groups. Pathological stage was the dominant clinical variable. A total of 14 patients (50%) had advanced stage disease and all died within 12 months of diagnosis. Nearly all of these patients showed abnormal ploidy patterns and ploidy analysis was not useful prognostically for this group. In contrast, all 3 patients with squamous cell carcinoma of the renal pelvis who were long-term survivors had deoxyribonucleic acid diploid tumors. However, there is no clear statistical evidence from this study that ploidy analysis provides important prognostic information independent of stage and grade for patients with squamous cell carcinoma of the renal pelvis.

Adult↗

Computer assisted screw insertion into real 3D rapid prototyping pelvis models.

OBJECTIVE: Show the use of computer navigation in exact screw positioning in the different pelvic bones. BACKGROUND: Computer assisted pedicle screw insertion in the spine is an established procedure. Screw fixation is also used in highly difficult pelvic and hip surgery (arthroplasty revision surgery and tumor surgery). DESIGN: Insert as long screws as possible with computer navigation into the different bones of the pelvis and compare these results with a non-computer controlled method. METHODS: The computer navigation was done with the system of Medivision (Oberdorf, Switzerland), the software was SurgiGATE 2.1. Optically controlled spine instruments and a special calibrated drill were used. The screw insertion with and without computer navigation took place in seven real rapid prototyping pelvis models matched by pairs. Three screws were inserted into the Os ileum, one into the Os pubis and one into the Os ischium. The length of the inserted screws were measured and compared using routine statistic methods. RESULTS: The mean screw length with vs. without computer navigation was 8.9 vs. 5.7 cm in the Os ileum (P=0.0001), 6.0 vs. 4.2 cm in the Os pubis (P=0.01) and 4.3 vs. 3.9 cm in the Os ischium (not significant). CONCLUSIONS: The use of computer navigation allows for the insertion of longer screws into the bones of the pelvis (more exact positioning), which requires a more precise original point of entry and direction of the drill (vector). RELEVANCE: The insertion of fixation screws in highly difficult pelvic and hip surgery (revision arthroplasty, tumor surgery) are another field for the use of computer navigation.

Arthroplasty, Replacement, Hip↗

Acceleration patterns of the head and pelvis when walking on level and irregular surfaces.

The aim of this study was to evaluate acceleration patterns at the head and pelvis while subjects walked on a level and an irregular walking surface, to develop an understanding of how the postural control system responds to challenging walking conditions. Thirty young, healthy subjects walked on a level corridor and on artificial grass underlain with foam and wooden blocks placed in an arbitrary manner. Temporo-spatial gait parameters and acceleration patterns at the head and pelvis were measured. The results revealed that when walking on the irregular surface, subjects were able to maintain their velocity, but adopted a slower and more variable cadence and a significantly longer stride length. The magnitude of pelvis accelerations increased, however head accelerations were not affected by the walking surface. When considered as an overall pattern of movement, these findings suggest that one of the primary objectives of the postural control system when walking on irregular surfaces is head control, and that subjects adapt their stepping pattern on irregular surfaces to ensure that the head remains stable.

Acceleration↗

Kinematics of the human pelvis following open book injury.

The objective of this study is to determine the three dimensional kinematics of the human pelvis including both sacroiliac joints following a simulated open book injury induced on cadavers by applying anterior-posterior compressive loads to the pelvis. An electromagnetic digitizing and motion tracking system was utilized to measure the morphology of the pelvis and the relative movements of its bones during this simulated open book fracture. The screw displacement axis method was used to describe the relative motion between the sacrum and each hipbone. Morphologically, it was found that the articular surfaces forming the sacroiliac joints could be approximated with planar surfaces directed from proximal and lateral to distal and medial and from posteromedial to anterolateral. The kinematic data obtained from this study indicate that there is a direct correlation between the opening of the symphysis pubis and the opening of the sacroiliac joint (SIJ) during open book injury. This suggests that the extent of injury of the SIJ maybe estimated from the degree of opening of the symphysis pubis as demonstrated on anteroposterior (A-P) x-rays. The results obtained from this study also indicate that the motion of the hipbone with respect to the sacrum on the side of the sacroiliac joint opening is almost a pure rotation, which translates clinically on the A-P x-rays as pure opening of the SIJ without vertical displacement. The average axis of rotation was found to be almost parallel to the SIJ planar articular surface. Furthermore, the pubic bone on the side of SIJ opening was found to displace inferiorly and posteriorly. One can thus conclude that in open book pelvic injuries, the pubic bone on the side of injury displaces inferiorly on the outlet projection x-rays with no vertical displacement of the SIJ. This is important since the initial assessment of the open book injury in the emergency room includes outlet projection x-rays. From this study, the relative vertical positions of the pubic bones on these x-rays can help the surgeon in differentiating open book fracture injury from other pelvic injuries.

Cadaver↗

Management of soft tissue sarcomas of the abdomen and pelvis.

OBJECTIVE: Soft tissue sarcomas of the abdomen or pelvis are rare tumours that usually arise in the retroperitoneum but may also arise from the gastrointestinal tract or other abdominal organs. The aim of this study was to assess patient outcome following treatment of these tumours at a tertiary referral centre. PATIENTS AND METHODS: Data on all patients with soft tissue tumours treated under the care of one surgeon between January 1990 and December 2000 was reviewed. RESULTS: Over the 11-year period 61 patients underwent 79 operations for a soft tissue sarcoma of the abdomen or pelvis. Macroscopic clearance of tumour at operation was achieved in 45 (74%) of the 61 patients, for primary tumours this was 97%, recurrent tumours 50% and metastases 33%. The median survival for those undergoing complete resection was 50 months (range 3-238 months, median follow-up 33 months). This compared with a median survival of only 6 months range (1-127 months) for those that had incomplete resection (P = 0.001). The 5-year survival for patients that had complete resection was 61.5%, however, over one-third of the 5-year survivors have since recurred. CONCLUSION: This study confirms that most primary soft tissue sarcomas of the abdomen or pelvis are resectable and the majority of patients will experience a long disease free interval following resection.

Abdominal Neoplasms↗

Current concepts in magnetic resonance imaging of the adult hip and pelvis.

MRI is the diagnostic imaging modality of choice for most disorders of the hip and pelvis in the setting of nondiagnostic plain radiographs. Quality images of the entire pelvis with high-resolution images of the affected hip are recommended. Intravenous gadolinium is administered in cases of suspected soft-tissue or bone infection. MR arthrography enables assessment of the joint space and the acetabular labrum. With MRI, the radiologist has the ability to stage pathological conditions of the hip and pelvis in such a way as to determine prognosis and influence therapeutic decisions.

Acetabulum↗

[MR Imaging of the pelvis in the diagnosis of the endometrium in breast cancer patients in tamoxifen therapy].

PURPOSE: The purpose of the study was to determine the value of MR imaging of the pelvis in the diagnostic work-up of the endometrium in breast cancer patients in tamoxifen therapy. MATERIALS AND METHODS: MR imaging of the pelvis was performed on 24 patients (mean: 62 years, range: 51 - 74 years) and 30 healthy women (mean: 65 years, range: 51 - 73 years). The volume of the uterus and cervix and the maximal thickness of the endometrium, junctional zone and myometrium of the uterus were determined and compared to the confidence interval of the parameters in healthy women. The Mann-Whitney U-test was used to identify differences in the volume of the uterus and cervix and in the thickness of the uterine wall layers in both groups. RESULTS: A comparison of the volume of the uterus and cervix and the thickness of the uterine wall layers in the two groups yielded no significant differences. The volume of the uterus and cervix showed no statistical differences between the two groups. The maximal height of the endometrium in the patient group showed a mean of 0.6 cm (range: 0.1 - 2.2 cm), and a mean of 0.4 cm (range: 0.1 - 1.2 cm) in the group of healthy women. The differences were not statistically significant. In all healthy women the endometrium showed homogeneous signal intensity in the sagittal T2-weighted images. In 12 of the 24 breast cancer patients, the endometrium showed inhomogeneous signal intensity. In 9 of 12 patients with an inhomogeneous endometrium with a thickness equal to or greater than 0.6 cm, histopathology confirmed polyps. In 3 patients endometrium hyperplasia was found. In one patient histopathology revealed a polyp and an endometrium carcinoma in stage T1 a N0. The endometrium carcinoma was not able to be seen via MR imaging. CONCLUSION: MR imaging might be helpful in the diagnosis of endometrium pathologies during tamoxifen therapy. Therefore, MR imaging of the pelvis could be used as a diagnostic tool in the follow-up diagnosis of the endometrium in breast cancer patients in tamoxifen therapy.

Adenocarcinoma↗

[Legal assessment of fractures and ruptures of the pelvis].

Since it is very difficult to arrive at a complete picture of the very varied effects of fractures and ruptures in the pelvic region, the few studies that have so far dealt with the assessment of injuries to the pelvic girdle have been unable to develop any uniform guidelines. An analysis of the clinical, radiological and in particular CT studies that have been published to date shows that there is a well-defined relationship between clinical and radiological symptomatology. This allows cases to be assessed expertly and objectively. Where there are unstable pelvic girdle fractures, follow-up examinations can use the extent of symphyseal diastasis and the dislocation of one or both halves of the pelvis in relation to the sacrum as a yardstick to assess the effects of injury on the posterior pelvic girdle and their consequences - effects which would otherwise be difficult to detect. Only where there are symphyseal diastases of more than 15 mm with degenerative alterations of the sacroiliac joint and permanent dislocation of one half of the pelvis does an impairment of earning capacity of 20% apply. Impairment-of-earning-capacity rates of 30-40% are appropriate in cases with completely unstable pelvic girdle fractures involving dislocation of both halves of the pelvis and posttraumatic arthritis in the sacroiliac joints. All other pelvic girdle or iliac wing fractures qualify for a maximum 10% reduction in earning capacity, even if the symphysis has become rigid.

Disability Evaluation↗

[Compensatory joints at the pelvis (author's transl)].

An osteochondrosis ischio-pubica represents a "testing site" for the integrity of the pelvis not only during child age but in adults as well. If all naturally available compensatory mechanisms have been exhausted especially following a change of range of motion in the pelvis ring structure, fatigue fractures or zones in transformation in the area typical of osteochondrosis ischio-pubica may appear. These fractures or transformation zones respectively to our mind have joint character, because they are capable of temporarily replacing lost mobility of physiological joints. Healing is achieved through rest, muscular balance and a specific physiotherapy. The purpose of this muscular training is to cushion all unphysiological motions in the pelvis and to support and boost the function of those joints still well preserved.

Biomechanical Phenomena↗

Standard orientation of the pelvis: validation on a model and ten patients.

PURPOSE: To validate an image post-processing method for re-orienting the pelvis in CT volumes to a standardized orientation in a model and in 10 patients. MATERIAL AND METHODS: Twenty-four CT volumes of a pelvic model and 10 pairs of postoperative total hip arthroplasty (THA) patient CT scans were rotated to a defined pelvic standard orientation and the rotation was recorded. For precision, a test-retest procedure was used. For accuracy, three exactly represented coordinate points were used. For clinical application, the standard orientation was used for calculating the direction of acetabular cup migration from a previous model study. RESULTS: Precision of pelvic standard orientation, calculated as maximal directional error, was better than 1 degrees in the model study and better than 1.5 degrees in the patient study. Accuracy, expressed as angle between ideal and measured coordinate axes, was 0.1 degrees for x, y, z axes. No measurable systematic errors were found. When applied to acetabular cup migration in the model, standardization of pelvic orientation had no significant effect on the measurements. CONCLUSION: Reorienting the pelvis during image post-processing was shown to be accurate. It enables measurements relative to the pelvis and minimizes the dependency of patient positioning.

Adult↗

3D reconstruction of the pelvis from bi-planar radiography.

3D personalized models are more and more requested for clinical and biomechanical studies. Techniques based on bi-planar X-rays present the advantage of a low radiation dose for the patient. However, up to now, such techniques have shown limited accuracy in the case of pelvis reconstruction. This study proposes and validates a method providing accurate 3D personalized model of the pelvis from bi-planar X-rays. The algorithm is based on the fast computation of an initial solution followed by local deformations based on 2D anatomical points and contours that are digitized in both radiographs. Results were close to CT-scan reconstructions (mean difference 1.6 mm and differences under 4.3 mm for 95% of the points). Moreover, 3D morphometry of the pelvis could be obtained with an accuracy of 5%. This technique provides 3D patient specific model with a low radiation dose.

Aged↗

Diagnosis of peripheral nerve sheath tumors around the pelvis.

OBJECTIVE: To distinguish between benign and malignant peripheral nerve sheath tumors around the pelvis. METHODS: A retrospective study of 30 patients with benign and malignant peripheral nerve sheath tumors located around the pelvis was performed. Clinical, imaging and histological features of 19 benign and 11 malignant peripheral nerve sheath tumors around the pelvis were reviewed retrospectively. RESULTS: Nearly all patients exhibited pain at presentation in cases involving both benign and malignant tumors. Although tumor size, duration of symptoms and presence of sensory disturbance possessed little value in differential diagnosis, severe motor weakness was observed exclusively in patients presenting with malignant tumors. On CT or MRI, central enhancement was apparent in 11 of the 19 benign tumors; in contrast, central enhancement was evident in one of the 11 malignant tumors. Fine needle aspiration cytology was performed in 11 tumors; correct diagnosis was achieved in four tumors. Core needle biopsy was performed in five tumors, all of which were correctly diagnosed with no neurological deficits. Immunohistochemically, all benign tumors were diffusely positive for S-100 protein, whereas malignant tumors were negative or focally positive for S-100 protein. Ki-67 index was less than 4% in all benign tumors; additionally, this index was 7-36% in malignant tumors. CONCLUSION: Central enhancement pattern on imaging studies strongly suggests a benign tumor; in contrast, severe motor weakness suggests malignant lesions. Core needle biopsy was reliable with respect to preoperative diagnosis.

Adolescent↗

Radiologic evaluation of the pelvis.

Careful radiographic assessment is essential in the diagnosis of pelvic fractures. The standard radiographic assessment of the pelvis includes the anteroposterior, inlet, outlet, Judet views, and axial computed tomography images. The different radiographic projections of the pelvis and their corresponding anatomic landmarks and the anatomy of the pelvis and the different anterior and posterior pelvic lesions are discussed. Description of the proper views and their uses are included.

Bone Screws↗

Combined posterior pelvis and lumbar spine resection for sarcoma.

The oncologic outcome in the treatment of pelvic sarcomas is not comparable with that in the extremity. Particular problems arise when the tumor involves the posterior pelvis and the sacrum or even the lower lumbar spine. Because of the difficulty in achieving local control and the major functional deficits after extensive surgery, some authors suggest conservative, nonsurgical treatment for these patients. The purpose of the current study was to analyze the oncologic outcome of patients who were treated for a pelvic sarcoma necessitating resection of the ilium, part of the sacrum and part of the lower spine, which is defined as extended hemipelvectomy. Between 1979 and 1999, 11 males and seven females with a mean age of 34.5 years (range, 14-67 years) had an extended hemipelvectomy for a sarcoma of the posterior pelvis. The tumors included seven osteogenic sarcomas, six chondrosarcomas, and five fibrosarcomas: 13 were classified as high-grade lesions. The mean size of the tumor was 11 x 9 x 6 cm. In 11 patients, a hemivertebrectomy of L5 and in seven patients of L4 combined with L5 was done to achieve an adequate margin. In four patients, the resection was followed by reconstruction with a vascularized fibula or autograft. At a mean followup of 56 months (range, 3-220 months), 12 of 18 patients were alive and without disease. Six patients died; four of these patients had metastasis to the lung at presentation. The two remaining patients died of complications of adjuvant treatment. The authors conclude from this small series of patients that an aggressive surgical resection for localized, nonmetastatic, high-grade sarcomas of the posterior pelvis may be justified to provide local control and improve survival.

Adolescent↗

In vivo estimation of radiation dose in renal pelvis and parenchyma during renography.

A method is presented for the determination of the spatio-temporal distribution of the radionuclide in the kidney and estimation of the dose in the renal pelvis wall and parenchyma, during renograms, on the basis of real data. A protocol was formulated by means of which the processing of the frames acquired in the various stages of the renogram enables the determination of the mass of the renal pelvis and the parenchyma as well as the time distribution of radioactivity in these compartments. The proposed methodology was applied to 30 normal subjects and 35 patients with obstructive nephropathy, acute and chronic obstructive uropathy and hydronephrosis. Our results, when compared with the MIRD dose estimations for the entire kidney showed slight deviations in normals, whereas very significant deviations were observed in the cases with pathology. This is due to the fact that the mass of the 'source' and 'target' organs as well as the biodistribution of the radiopharmaceuticals are essential in dose determination and were completely different in our calculations from those used in the MIRD estimations. Comparing the absorbed dose in renal parenchyma and pelvis wall with that estimated in vivo for the kidney considered as a system of one compartment, we found large differences only in abnormal cases. Differences were also noted between the absorbed dose in the aforementioned renal compartments depending on the considered abnormal renal states.

Adult↗

Immediate complications of Cotrel-Dubousset instrumentation to the sacro-pelvis. A clinical and biomechanical study.

The authors reviewed the early complications in all patients fused to the sacro-pelvis using Cotrel-Dubousset instrumentation at the Texas Scottish Rite Hospital. Sixteen patients were studied with an average follow-up of 13 months. Three methods of sacro-pelvis fixation were evaluated: iliosacral screws, sacral screws, and a technique whereby the caudle ends of the Cotrel-Dubousset rods were fashioned and inserted into the posterior iliac crest using the Galveston technique. Seven of the 16 sets of sacral screws (44%) failed during and after surgery. Two of the 7 sets of iliosacral screws failed postoperatively (28%). No failures occurred in the 8 sets of Cotrel-Dubousset rods placed with the Galveston technique. Seven of the nine medical complications observed (77%) occurred in the sacral screw group. Using calf spines, a biomechanical evaluation of each system was undertaken to determine strength of fixation. Each system was failed in flexion 3 times. The sacral screws were the weakest, pulling directly out of the sacrum at 40 N-M. Cotrel-Dubousset rods inserted with the Galveston technique were the strongest, experiencing rod deformities before flexion failure at 70 N-M. Iliosacral screws were of intermediate strength failing by rotation on the axis of the screws or pulling directly out of the ilium at 55 N-M. The authors conclude that using Cotrel-Dubousset rods inserted with the Galveston techniques was the strongest and safest method of sacro-pelvis fixation of the three tested.

Adolescent↗