An Atraumatic Sacral Fracture with Lumbosacral Radiculopathy Complicating the Early Postpartum Period: A Case Report

Pregnancy-Related Sacral Stress Fractures: A Single Center Experience of 23 Cases

Purpose

This study aims to find out the incidence, etiology, and risk factors, define clinical features, show the magnetic resonance imaging (MRI) and laboratory findings, and share the experience of treatment and clinical outcome of pregnancy-related sacral stress fractures (SSFs).

Methods

In total, 29,291 (15,008 of them vaginal and 14,283 of them cesarean section delivery) women gave birth in our hospital between January 2016 and December 2021. Twenty-three of them (0.078%) who had low back and pelvic pain were diagnosed with SSFs using pelvic MRI. Dual-energy X-ray absorptiometry (DEXA) was used to rule out underlying osteopenia and osteoporosis and determine the type of SSFs.

Results

The incidence of pregnancy-related SSFs was 0.078% (23/29,291patients). Six patients (26%) experienced pain during the last trimester of pregnancy, remaining seventeen (74%) patients had pain during the postpartum period. 73.91% of the patients were primigravida. Thirteen patients (56.52%) were classified as fatigue SSFs, eight (34.78%) were insufficiency SSFs, and only two (8.7%) were defined as a mixed type of SSFs. MRI imaging showed that nine patients (39.13%) had a left-sided fracture, seven patients (30.43%) had a right-sided fracture, and seven patients (30.43%) had bilateral fractures. Vitamin D deficiency (less than 20 ng/mL) was detected in seven patients (30.44%). One case had hypothyroidism in which thyroid stimulating hormone (TSH) was 5.41 μIU/mL.

Conclusion

Pregnancy-related SSFs are uncommon but should be considered by clinicians in the differential diagnosis of low back and pelvic pain during pregnancy and the postpartum period. We determined that first pregnancy is a risk factor for SSFs. The current study also revealed that laboratory investigation of vitamin D deficiency and DEXA investigation, which may lead to osteoporosis or osteopenia, were crucial in the diagnosis. Furthermore, some SSFs should be reclassified as mixed fractures, fatigue, and insufficiency fractures.

Postpartum bilateral sacral stress fracture without osteoporosis-a case report and literature review

PURPOSE

Sacral stress fractures are rare complications which can arise during pregnancy or in the early postpartum period. We report a case and discuss the findings of a confirmed postpartum sacral stress fracture in a 39-year-old multiparous woman and review previous case reports in the literature of sacral stress fracture related to pregnancy.

METHODS

A review of the literature was conducted to examine the main characteristics of sacral stress fractures related to pregnancy. The Ovid/Medline, Embase and Google Scholar databases were searched with the inclusion criteria: human studies, English language, intrapartum, postpartum (within 6 months of parturition), sacrum and stress fracture. Our exclusion criteria included pubic fractures, vertebral fractures and non-English articles. The search terms included "stress fracture", "postpartum", "pregnancy", "atraumatic" and the wildcard "sacr*". Thirty-four cases were found and summarised in Table 2.

RESULTS

A total of 65% of patients had onset of symptoms postpartum. Most patients did not have risk factors for sacral stress fractures including macrosomia, excessive pregnancy weight gain, heparin exposure, rapid vaginal delivery or predisposition to accelerated osteoporosis. Lumbar radiculopathy can be a feature of sacral stress fracture and it is more common (17.6%) than reported in the literature (2%). MRI is the preferred imaging modality for its safety profile in pregnancy and high sensitivity. A total of 70% reported normal bone mineral density (BMD). The mainstay treatment for sacral stress fractures includes relative bed rest, analgesia and modified weight-bearing exercises. Most patients have favourable outcome with complete symptom resolution.

CONCLUSION

Sacral stress fractures in the absence of osteoporosis are rare complications of pregnancy that can present with lumbar radiculopathy. Conservative management often produces good clinical outcomes.

High prevalence of spondyloarthritis-like MRI lesions in postpartum women: a prospective analysis in relation to maternal, child and birth characteristics

OBJECTIVES

Bone marrow oedema (BMO) on MRI of sacroiliac joints (SIJs) represents a hallmark of axial spondyloarthritis (SpA), yet such lesions may also occur under augmented mechanical stress in healthy subjects. We therefore sought to delineate the relationship between pregnancy/delivery and pelvic stress through a prospective study with repeated MRI. Results were matched with maternal, child and birth characteristics.

METHODS

Thirty-five women underwent a baseline MRI-SIJ within the first 10 days after giving birth. MRI was repeated after 6 months and, if positive for sacroiliitis according to the Assessment of SpondyloArthritis International Society (ASAS) definition, after 12 months. BMO and structural lesions were scored by three trained readers using the Spondyloarthritis Research Consortium of Canada (SPARCC) method.

RESULTS

Seventy-seven per cent of the subjects (27/35) displayed sacroiliac BMO immediately postpartum, 60% fulfilled the ASAS definition of a positive MRI. After 6 months, 46% of the subjects (15/33) still showed BMO, representing 15% (5/33) with a positive MRI. After 12 months, MRI was still positive in 12% of the subjects (4/33). Few structural lesions were detected. Intriguingly, in this study, the presence of BMO was related to a shorter duration of labour and lack of epidural anaesthesia.

CONCLUSION

A surprisingly high prevalence of sacroiliac BMO occurs in women immediately postpartum. Our data reveal a need for a waiting period of at least 6 months to perform an MRI-SIJ in postpartum women with back pain. This study also underscores the importance of interpreting MRI-SIJ findings in the appropriate clinical context.