Back pain post partum : clinical and experimental studies

Abstract

Background: Half or more of pregnant women experience back pain at some time during pregnancy. Even though back pain exists post partum, it is not well documented and detailed studies concerning different back pain localisations, experiences of pain and activity abilities are scarce. Thus, the prevalence of back pain post partum varies highly, between 2% - 65%, due to different follow-up times, methods and definitions of persisting back pain.

Aim: The aim of this thesis was to 1) identify and classify back pain in women post partum and its relation to experience of pain and ability to perform daily activities; 2) quantify differences in kinematics above all with respect to joint co-ordination, temporal parameters and pelvic motion in a lifting task; 3) evaluate how different treatments performed during pregnancy affected pain and activities during pregnancy and in the post partum period.

Methods: On average 7 months post partum 119 women were examined and interviewed. The spinal sagittal configuration and mobility were measured in the thoracic and lumbar spine, respectively, with a kyphometer. Eight pain provocation tests were performed for the lumbar spine, sacroiliac joints and symphysis and in addition hip movement and radiating pain were examined. Pain intensity was rated on a visual analogue scale (VAS 0-100 mm) and described with regard to localisation of pain and type of sensation on a pain drawing. Activity ability was scored using the Disability Rating Index (DRI) covering 12 items each rated on a VAS 0-100 mm. Based on clinical examination, 118 women with pelvic girdle pain diagnosed during pregnancy were randomised into three different treatment groups. They were followed throughout pregnancy and until 12 months post partum with respect to perceived pain and self-estimated activity limitations. All three groups received information about the condition and were provided with a non-elastic sacroiliac belt (Rehband®, Sweden). Group 2 received in addition a home training programme consisting of three exercises aiming to activate the muscles around the pelvic girdle and stretching exercises. Group 3 participated in addition in an individual training programme consisting of strengthening exercises. Seven women with low-back pain and nine women without low-back pain participated in a laboratory study on average 6 months post partum. The lifting task consisted of lifting an 8.3 kg box with both hands. A two-camera opto-electronic system (ELITE, BTS, Milan, Italy) recorded the positions of 14 passive light- reflecting markers for calculations of joint and segment angles.

Results: In 27% of the women, pain could be provoked in the area of the posterior pelvic/sacroiliac joints, in 18% in the lumbar spine, in 39% in both areas and in 16% no pain could be provoked in the defined areas. The spinal sagittal configuration or mobility and perceived pain intensity did not differ between the groups. In the three groups where pain was provoked in the lower back area, the ability to carry out above all movement related daily activities, was more limited than in the group where no pain could be provoked in that area. There was no significant difference between the three intervention groups during pregnancy or at the three follow-ups regarding pain and activity. In all groups, pain decreased and the activity ability increased between gestation week 38 and at three months follow-up. The performance of the lifting task differed between the women with and without low-back pain concerning the hip-pelvic-lumbar spine motions. The pain group had less hip joint flexion and more lumbar spine flexion at box lift-off. A large percentage in the pain group also showed a non-stop flexion-extension motion of the lumbar spine and an unsteady pelvis motion in space around lift-off.

Conclusions: Pain could be provoked from different locations in the back and can thus not be seen as a unitary concept. The measuring of the spinal sagittal configuration and mobility did not further identify or classify post partum back pain. Pain is a symptom, but activity limitations seem to be important, since the findings showed limitations in movement related activities. Performing exercises had no additional value when compared to giving a non-elastic sacroiliac belt and information. During performance of a lifting task, dissimilar kinematics were shown in the motion of the hip-pelvis-lumbar movement. It seems important to pay attention to women with back pain post partum, in order to prevent prolonged pain.