Research Review By Dr. Shawn Thistle©

Date Posted:

September 2009

Study Title:

Posterior pelvic pain provocation test is negative in patients with lumbar herniated discs

Authors:

Gutke A, Hansson ER, Zetherström G, Östgaard HC

Author's Affiliations:

Physical Therapy Departments – Linköping University, Frölunda Specialist Hospital, Sahlgrenska University Hospital (Sweden)

Publication Information:

European Spine Journal 2009; 18: 1008-1012.

Background Information:

Previous studies suggest that roughly 45% of women experience some form of lumbopelvic pain during pregnancy, while 25% continue to experience symptoms after delivery (1). Sometimes these pain syndromes can be resistant to intervention and develop into long-lasting issues.

One of the most common classifications of back pain experienced during pregnancy is termed Pelvic Girdle Pain (or PGP, sometimes referred to as Posterior Pelvic Pain of Pregnancy or PPPP – for this review these terms will be considered equivalent). PGP is considered as a specific form of LBP that can occur separately or in conjunction with LBP (2). Normally, PGP is reported between the posterior iliac crest and gluteal crease, most predominantly near the sacroiliac joint and its associated ligaments. Exclusive or associated pubic symphysis pain may be present, as well as referred pain in the posterior thigh.

Various clinical tests have been proposed to assess PGP such as the Posterior Pelvic Pain Provocation Test (P4 – the subject of this study), the Active Straight Leg Raise (ASLR) and pain provocation test of the long dorsal SI joint ligament. (SIDE NOTE: in another study from 2009, the ASLR and belief in improvement potential were identified as the most important prognostic factors for PGP recovery, while interestingly previous LBP and high psychological distress were not as important [2]).

Some have suggested that the P4 test may also have an effect on lumbar structures, and thus be positive in those with pain originating from the lumbar spine. This would, of course, reduce its utility in assessing PGP. This is in spite of some existing literature that indicates that most lumbar spine pain syndromes are not directly affected by pregnancy (3). A prudent clinician will always attempt to rule out lumbar pain generators before arriving at a diagnosis of PGP, so it would be useful to know which tests are helpful in differentiating these conditions.

The purpose of this study was to examine the results of the P4 test in two patient groups: those with a well-defined lumbar diagnosis and those with pelvic girdle pain during pregnancy and persistent PGP after delivery.

Pertinent Results:

How to perform the Posterior Pelvic Pain Provocation Test (P4):
The subject is lying supine with the hip flexed to 90° (with knee bent) – the examiner then stabilizes the opposite side of the pelvis via the ASIS with a palm contact while applying light downward manual pressure along the longitudinal axis of the femur. The test is considered positive when a familiar, sharp, localized pain is reported deep in the gluteal area on the provoked side.

Results when the P4 test was performed on the two patient groups (those with PGP during or after pregnancy, and those with lumbar disc herniations pre/post surgery):
  • the sensitivity of the P4 test for PGP was 0.88 and specificity was 0.89
  • the positive predictive value of the P4 test was 0.89 and the negative predictive value was 0.87
  • the P4 test was negative in all but 3 of 23 patients with well-defined lumbar disc herniations prior to surgery, and 3 of 30 similar patients 6-weeks after surgery
  • when analyzing just female subjects, the results were similar

Clinical Application & Conclusions:

This study was small and simple, but its results suggest that the Posterior Pelvic Pain Provocation test can be used with confidence in assessing Pelvic Girdle Pain. It appears sensitive and specific for PGP, which supports other studies that have examined this test. Further, it does not appear to aggravate patients with confirmed lumbar disc pathology.

Study Methods:

The P4 test was performed on two patient groups and two control groups – for the analysis, the two control groups were combined, as were the two patient groups (the statistics for all groups were presented separately). The groups were:
  1. Control 1: patients with one or more CT-verified lumbar disc herniations who were on a waiting list for surgery
  2. Control 2: patients who had undergone surgery 6 weeks prior for lumbar disc herniations that were verified by CT scan
  3. Patient 1: pregnant women who were experiencing PGP
  4. Patient 2: post-partum women classified as having persistent PGP
Those with PGP had to report pain in the gluteal region with or without radiation down the leg – a typical PGP presentation. Patients were excluded from all study groups if they had mixed PGP/LBP presentations, obstetric complications (for the pregnant subjects), hip disorders, symphysiolysis, systemic disease or history of neoplasm, severe spinal illness, history of mental illness, or if they were unable to assume the P4 test position due to pain severity.

Study Strengths / Weaknesses:

This study could have been strengthened by a larger sample size. However, its design and intent were simple, and the results provide consistent evidence that the P4 test is unlikely to be positive in those with confirmed lumbar spine disc pathology, both before and after surgery – this was the primary goal if this investigation.

The authors appropriately note one potential limitation of this study – the assessing physiotherapist was not blinded to those patients with disc herniations. Although unlikely, this may have influenced the results. Future studies should blind the assessing clinicians.

It is worth noting that there is no gold standard test to identify PGP, so the authors used the combination of history and clinical presentation with pain drawing results to identify the patient groups in this study. This approach is supported by current practice guidelines (4).

Additional References:

  1. Wu WH et al. Pregnancy-related pelvic girdle pain (PPP). I: Terminology, clinical presentation, and prevalence. Eur Spine J 2004; 13: 575-589.
  2. Vollestad NK, Stuge B. Prognostic factors for recovery from postpartum pelvic girdle pain. Eur Spine J 2009; 18: 718-726.
  3. Ostgaard HC et al. Regression of back and posterior pelvic pain after pregnancy. Spine 1996; 21: 2777-2780.
  4. Vleeming A et al. European guidelines for the diagnosis and treatment of pelvic girdle pain. Eur Spine J 2008; 17: 794-819.