Comparative Study Of Intra-Operative Pelvimetry With Calipers And X-Ray Pelvimetry

Abstract

The pelvic measurement of patients who have had a caesarean section was done using Pelvic Calipers (intra-operative) and x-ray methods. In the former method, during Caesarean sections and after closure of the lower uterine segment incision, a pair of pelvic calipers was used to measure the true conjugate of the pelvis. In the other method and same subject, between the 5th and 7th post-operative days when the patient could stand up right, an erect lateral pelvimetry was done (if this was not done prior to delivery) and the true conjugate was measured independently by the radiologist. For those who had x-ray pelvimetry prior to delivery, the true conjugate was measured from the previous radiograph. The average age and height of the patients were 27.5yrs and 160cm respectively. Cephalo-pelvic disproportion was the indication for sixteen (42%) of the primary Caesarean sections. The mean true conjugate diameter of the pelvis (cm) obtained by intra-operative pelvimetry and x-ray pelvimetry were 10.80 (SD 1.28) and 10.90 (SD 1.27) respectively. The difference between the two values was not significant (t < 1.98). The values of true conjugate obtained by both methods showed the same variation with height, age and parity. Patients with cephalo-pelvic disproportion had statistically smaller true conjugate than others when assessed by both methods. There is a strong correlation between intra-operative use of calipers and x-ray method in the measurement of true conjugate. It is thus concluded that intra-operative pelvic measurements using a pair of pelvic calipers (which is a direct measurement) could replace x-ray measurements in assessing pelvic size.

Keywords: Pelvic measurement, caesarean section, X-ray pelvimetry.

Annals of Biomedical Science Vol. 4 (1) 2005: pp. 19-24