Biomedical subjects
Publications and source records attributed to G G Walheim.
A specially designed compression plate has been used in symphysiodesis for chronic symphysiolysis with pelvic pain and discomfort suspected to be due to pelvic instability. Eight patients have been operated with this technique, and stable symphysiodesis was achieved in all. No signs of plate loosening were observed in any case.
Pelvic instability is a controversial concept. The symptoms and signs are believed to be due to pelvic joint hypermobility. Differentiation from low back pain can often be difficult. As an aid in diagnosis, temporary external fixation of the pelvis with a trapezoid compression frame was used in 12 patients. The effect on clinical signs and limping, tested on an electronic walkway, and symphyseal mobility has been analysed: in 11 of the 12 patients the frame had a positive clinical effect. In five of six patients limping diminished significantly. Stabilizing of symphyseal mobility could not be demonstrated.
Pelvic instability is a term widely used to describe a clinical entity characterized by pain localized to the pubic symphysis and/or sacroiliac joints. The pain often radiates down the leg. Hypermobility of the pelvic joints has been suggested as the cause of pain. Apart from several clinical stress tests, attempts at establishing objective evidence of such mobility have mainly consisted in radiologic measurement of motion of the pubic symphysis by a method which allowed only vertical movement to be recorded (5). In the present study symphyseal mobility was measured by an electromechanical method by which direct interosseous movement could be recorded in three directions and two different planes. Measurements were performed in a series of 15 patients with a tentative diagnosis of pelvic instability and the results compared to the results of radiologic measurement and to the normal values obtained in an earlier study of healthy volunteers (31). The results of this study would seem to refute the theory of symphyseal hypermobility being pathognomonic of so-called pelvic instability. It has moreover shown that radiologic measurement may be used for rough screening purposes, but is not sufficiently reliable for more exact measurements.
Mobility of the pubic symphysis can be measured in vivo by two new methods. One is electromechanic (EM), with steel pins inserted into the bone. The other is roentgen stereophotogrammetric analysis (RSA), with tantalum bone markers implanted into the hip bones. With the first method, movements are directly registered with resistive transducers mounted on the pins. With the second method, movements are deduced with kinematic analysis from roentgen stereophotogrammetric measurements of the positions of the bone markers. Both methods have high precision, about 0.1 mm for translations and 0.1 degrees for rotations. The methods were used in two young volunteers, a man and a woman. In provocative tests with identical loading (alternating, active straight-leg raising in the supine position and standing on alternating left or right leg) there was a good correlation between the two methods. The measured values, i.e., translations of up to 2 mm and rotations of up to 3 degrees, form a basis for more comprehensive studies of normal and pathologic mobility of the pubic symphysis.