Summary and Perspective of Recent Literature
David Ham, PT, Cert. MDT
The aim of this study was to determine the effects of a McKenzie-based exercise and postural program compared to usual care (advice, patient education, analgesics) for the management of back pain in pregnant women.
Back pain is a well-known problem that can occur during pregnancy, with etiological consideration given to hormonal and biomechanical factors. A multitude of treatment approaches have surfaced to manage this problem conservatively such as educational programs, exercise regimens, sacroiliac belts for pelvic girdle pain and manipulative therapy. MDT is frequently used to assess and manage back pain in the general population, but its effects in the pregnant population are not well known. One case series of 72 pregnant women with low back pain found that Derangement was present in 80%, with 76% of this group achieving an excellent or good outcome (Rath 1997).
This study investigated pain (Numeric Rating Scale) and disability (Modified Roland-Morris Disability Questionnaire) outcomes for pregnant women over a seven-week period. 466 pregnant women were purposively recruited from five Nigerian antenatal centres and assessed by one investigator holding the MDT Diploma. Participants were initially screened and subgrouped according to pain location: High Back Pain (HBP) in the thoracic region, Low Back Pain (LBP) in the lumbar area, and Pelvic Girdle Pain (PGP) in the pelvis. Participants were excluded if they could not understand English or Yoruba, had a complicated pregnancy, showed indicators of serious spinal pathology, demonstrated at least two signs of nerve root compression or had an expected date of delivery less than eight weeks. Participants with HBP or LBP were also excluded if they did not fit into one of the three McKenzie syndromes (author correspondence). Patients were then randomized into a Usual Care Group (UCG) or a McKenzie Protocol Group (MPG) including usual care.
Treatment protocols lasted six weeks with a final assessment one week following completion. Participants in the UCG received treatment as deemed appropriate by the patient’s physician which could include any or all of analgesics, counselling, postural education, and modification of activities of daily living. Participants in the MPG were given directional preference exercises (if indicated) and education on posture, avoidance of aggravating activities, prevention of recurrence, and self-management. One therapist assessed and treated all MPG patients. Repeated movement testing was limited to two to three movements in a given direction due to an ethical concern raised regarding repetitive movement in the presence of structural laxity; sustained positioning was also used. In the PGP group, if there was no response to movement or positioning then lumbopelvic manual techniques were used as a force progression; if again no response was seen then a sacroiliac belt was prescribed.
466 pregnant women were enrolled in the study, with 28 dropouts from the MPG and 16 from the UCG due to delivery dates earlier than expected. Only the participants who completed the study had their data analyzed.
Overall prevalence of the MDT syndromes as determined by initial screening is presented below (author correspondence).
Prior to treatment, there were no significant differences between the two treatment groups for age, parity, pain scores or disability scores. Participants within the MPG showed statistically significant and clinically important reductions in pain and disability for all pain location subgroups post-treatment; participants within the UCG showed statistically significant but not clinically important reductions in pain and disability only in the LBP and PGP subgroups. A between-group comparison revealed participants in the MPG achieved significantly greater reductions in pain and disability than those in the UCG across all pain locations:
The mean number of treatment visits for the MPG varied by pain location subgroup: LBP needed 2.41 (range 1-4), PGP 2.63 (range 2-4), and HBP 2.08 (range 1-3).
This study is an informative addition to the MDT literature as it provides evidence of the effectiveness of the approach in the pregnant population. The prevalence of Derangement and Directional Preference for the LBP and HBP groups is consistent with the previous case series (Rath, 1997), but interestingly for those in the PGP subgroup with directional preference, a slight majority responded to flexion. Importantly, robust results were shown in favour of MDT management; none of the participants in the usual care group achieved a clinically meaningful reduction in pain or disability, while all the McKenzie group participants did.
Strengths of this study included the large sample size with over 200 participants in each group and consistency in management of the MPG with one highly-trained therapist assessing and treating all participants. Additionally, MDT intervention was reflective of true clinical practice with an emphasis on self-management, postural education, temporary avoidance of aggravating factors and regular performance of reductive exercise.
Several limitations were noted. Firstly, the intervention in the usual care group was not standardized and was delivered by numerous care providers. Also, it is possible that some of the response seen in the MPG was due to a general exercise effect, since the usual care group did not receive any exercise interventions; an additional group performing non-specific exercises would have been enlightening to elucidate the specific impact of MDT. Furthermore, only two to three repetitions were performed in the repeated movement exam due to ethical concerns of structural laxity. This is an overly cautious approach; if the symptomatic response is followed then safety in the examination can ultimately be assured.
Despite these limitations, compelling and clinically important results were achieved in the MDT group. Thus, back pain in the pregnant population appears similar to the general population in that a high prevalence of Derangement is present and thus many will respond rapidly. Some procedures need to be modified but the system can be followed as for any other patient. Additionally, a notable finding from this study is that 52% of patients with pelvic girdle pain had a Directional Preference; therefore, just under half needed a sacroiliac belt as part of their care, less than what might be expected for this group.