Predictive Value of the Active Straight Leg Raise on the Efficacy of a SJB in Posterior PGP During Pregnancy

During pregnancy, women often experience musculoskeletal pain, specifically in their low back
and/or pelvic girdle. Pelvic girdle pain (PGP) is defined as pain between the posterior iliac
crest and gluteal fold, particularly in the region of the sacroiliac joint (SIJ)1. Although
it is often referred to as "sciatica". PGP in pregnancy is common with prevalence estimates
of 45%2. Previous studies have found that one third of patients will rate their PGP intensity
as severe, leading to functional impairments. Functional disabilities include sitting,
walking, and standing; thus, significantly impacting the ability of patients to perform
routine daily activities. This pain has been reported to develop as early as 17-19 weeks'
gestation, lasting up to 3 months postpartum; with a peak incidence of 24-36 weeks.

The etiology of PGP in pregnant women is still not fully understood, largely due to the
complex interactions between bone, ligaments, fascia, and muscles in the pelvic joints3. Some
studies suggest the increased mobility of the joints in the pelvic girdle during pregnancy
due to relaxing cause a lack of stabilization in the sacroiliac region, which results in
pain4. Thus, it is hypothesized that providing stabilization of the joints with an external
force, such as a maternity or SIJ belt, will improve pain.

Clinically, pelvic belts are often used as a part of a multimodal approach to reduce PGP
alongside other conservative treatments such as analgesics and physical therapy, or more
alternative treatments such as acupuncture5. This makes it difficult to determine their
individual effect on pain reduction. Further confounding this issue are variations in
physician counseling, physical therapy regimens, and analgesic usage. Moreover, several
support belts have been designed that vary in padding size, flexibility, and site of
application5-7. Among these belts, it has not yet been identified which belt is most
beneficial regarding pain reduction and patient tolerance5. Previous studies have found
benefit in short term use (3-6 weeks) of maternity belts, providing women with improved pain
and function compared to exercise or no intervention7. Pelvic belts are a cost-effective
option to treating PGP, and more specifically SIJ pain, yet studies are limited regarding the
effect they have on SIJ mobility and pain reduction8 and more specifically determining what
clinically predicts those who will benefit most from an SIJ belt.

The active straight leg raise test originally described by Mens is an examination maneuver
that measures functional mobility and has been correlated with pregnancy related PGP (cite).
Anecdotally, our clinical team has observed that women who benefit from compression during
the second part of the test, seem to benefit most from the use of an SIJ belt. Having a
simple test for obstetric providers to perform in pregnant women with pain would be
informative in determining who might benefit most from an SIJ belt. Hence our study seeks to
investigate the following aims:

Inclusion Criteria:

- English speaking pregnant women presenting in their second or third trimester with
posterior PGP. Trimester will be determined from date of last menses or ultrasound
date.

- Pain must be between the upper level of the iliac crests and the gluteal folds in
conjunction with or separately from pain in the pubic symphysis and influenced by
position and locomotion

- ASLR score between 2-10

Exclusion Criteria:

- Non-English speaking pregnant women <18 or >50 years old

- Women presenting with PGP in the first trimester (<13 weeks gestation)

- Women with pubic symphysis (anterior) pain alone

- Pain above the upper level of the iliac crest

- ASLR total score of <2

- History of lumbar or pelvic fracture, neoplasm, inflammatory disease, active
urogenital infection or active gastrointestinal illness, previous surgery of the
lumbar spine, pelvic girdle, hip joint or femur

- History or signs of radiculopathy or other systemic neurologic disease