INTRODUCTION

Nearly any medical condition that can occur in the nonpregnant state can occur during pregnancy. In fact, because of the pregnant state, women can potentially be at higher risk of misdiagnosis due to the overall general concept that all back pain in pregnancy is somewhat ‘normal’.¹ Back pain in pregnancy is common, but when it becomes disabling it demands further diagnostic evaluation. Estimates of incidence are 50–70%.² One prospective study of back pain in pregnancy showed a prevalence rate of 60%, with 30% of those patients reporting severe limitations in their daily activities.³

Special consideration of postpartum back pain should also be made in the context of the continuum of pregnancy-related pain.

The physiologic changes of pregnancy may predispose women to back pain. The increased lumbar lordosis combined with the effects of the hormone relaxin on the joints of the lumbar spine and pelvis with the added weight of the gravid uterus result in a shift of the center of gravity anteriorly and an increased mechanical burden on the low back.^2,4 The abdominal wall musculature of the abdominal cavity stretches as the gravid uterus grows. The force–tension curve of the lengthened abdominal muscles restrict their contractile strength while the muscles of the low back work harder to maintain upright posture. The muscles of the pelvic floor will bear the weight of the growing uterus and will eventually allow passage of the fetus. Relaxin is a polypeptide hormone secreted by the corpus lutea and has been identified as the major contributor to joint laxity during pregnancy.⁴ It is dramatically elevated during the first trimester, declines early in the second trimester to a level that remains stable throughout the pregnancy,⁴ and then declines sharply after delivery. Widening of the symphysis pubis and increased mobility of the sacroiliac synchondroses begins in the tenth to twelfth week of pregnancy as a result of relaxin.⁵ The strong sacroiliac ligament which normally resists forward flexion of the ala will become lax with the effects of relaxin.⁵ Weight gain, maternal obesity, and fetal weight at term have not been found to be related to pregnancy-related back pain.⁶ Other studies have shown that low back pain prior to or during a previous pregnancy, nulliparity with increased body mass index (BMI), lower socioeconomic status, and placenta with a posterior fundal location were found to be risk factors for back pain in pregnancy.³⁵ A spectrum of clinical symptoms may be produced by the physiologic changes of pregnancy. However, the differential diagnosis of back pain in pregnancy should not be limited to pregnancy-related changes in the musculoskeletal system.

Clinical entities implicated as causes of back pain in pregnancy in one review article include: pelvic insufficiency (pain), sacroiliac joint (SIJ) subluxation, sciatica, lumbosacral disc pathology, spondylolisthesis, postural back pain and lumbar lordosis, thoracic back pain and coccydynia.⁶ Other studies have also included hip pathology, such as osteonecrosis of the femoral head and transient osteoporosis of pregnancy, as a potential cause of referred back pain.⁵ Other known causes of back pain include neurologic etiologies such as radiculopathy or plexopathy, vertebral segmental dysfunction, tumor, or fracture of the sacrum or pelvis. There is also growing evidence that the pelvic floor musculature is a pain generator, especially in relation to coccydynia and dyspareunia (Table 123.1).

Table 123.1 Visceral Causes of Low Back Pain in Pregnancy⁶

PELVIC OBLIQUITY

The pelvis is a ring comprised of two innominate bones that are connected anteriorly by the pubic symphysis and posteriorly to either side of the sacrum by the SIJ. The pelvis is dynamic or more mobile in the pregnant state as a result of the influence of relaxin on the ligamentous structures. Laxity itself is widespread and does not necessarily result in pain. Asymmetry of any part of the ring will cause dysfunction on the opposite side, i.e. dysfunction of the posterior pelvis will result in asymmetry and dysfunction of the anterior pelvis. They do not occur in isolation. However, there is a clear relation between asymmetric laxity of the SI joints and pregnancy-related pelvic pain (PRPP).⁸

There is an array of nomenclature to describe a given obliquity. By convention, dysfunction of pelvic ring is named on the hypomobile side. However, anecdotally, in the pregnant state the hypermobile side on physical examination can correlate with the side of pain. Damen et al. studied the prognostic value of laxity in assessing pain postpartum. Asymmetric laxity of the SI joints in pregnancy was believed to increase the presence of pelvic pain postpartum by as much as threefold.^9,10 This speaks to treatment of asymmetry of the SI joint and its associated pain during pregnancy to prevent future back pain.

In pregnancy, the innominate obliquity is commonly named for the side which gives the patient pain in order to best direct the physical therapy prescription. A number of anatomic landmarks are used to determine pelvic obliquity: the iliac crest, the posterior superior iliac spine (PSIS), the anterior superior iliac spine (ASIS), and the pubic tubercles. The inferior lateral angle of the sacrum (ILA) can also be assessed to further delineate asymmetric sacral positioning in relation to ilial positioning. By measuring the side-to-side difference between these landmarks, the type of obliquity can be determined. A problematic hemipelvis can be rotated anteriorly or posteriorly, sheared superiorly (upslip) or inferiorly (downslip), inflared or outflared. Sacral positioning can be described similarly.¹¹

SACROILIAC JOINT DYSFUNCTION

The sacroiliac joint is a true joint consisting of a synovial component inferiorly. It is auricular-shaped with the thinner sacral side lined with hyaline cartilage and the thicker ilial side with fibrocartilage. Primary innervation to this joint is thought to be from S1. Sturesson, in 1989, described true movement of the SIJ measuring approximately 1–3° of rotation.¹² The sacroiliac joint has also been shown to be a potential generator of low back pain.¹³ In the pregnant patient, the potential for dysfunction is increased secondary to pregnancy-related hormone-induced ligamentous laxity and resultant asymmetry. It is thought that the laxity prepares for and facilitates delivery of the baby at term.¹⁴ Ostgaard, in a prospective study of back pain in 855 pregnant women, found an incidence of 19% with sacroiliac pain in week 30 of gestation.¹⁵ Additionally, Damen showed that in pregnant patients who were evaluated by Doppler imaging of vibrations there was found to be a definite relationship between asymmetric laxity of the sacroiliac joints and pregnancy-related pelvic pain.⁸ Patients typically report pain over the sacrum or the sacral sulcus. Transitional motions, particularly while turning in bed and arising from the seated to the standing position frequently triggers or exacerbates the presenting symptoms. Physical examination maneuvers will be discussed later, but posterior pelvic pain provocation test and active straight leg raise testing are well-documented, reliable diagnostic tests to assess pregnancy-related sacroiliac joint pain.

The relationship between pelvic obliquity and sacroiliac joint dysfunction is somewhat intuitive. Typically, when a persistent pelvic obliquity exists there is associated SIJ pain and dysfunction due to the anatomic relationship between these structures. The pelvic obliquity, which is secondary to ligamentous laxity, is thought to create the SIJ dysfunction and change in joint mechanics.

PELVIC FLOOR MYOFASCIAL PAIN

The pelvic floor is made up of two layers of muscles. The superficial layer of muscles including the ischiocavernosus, bulbocavernosus, and transverse perinei muscles make up the urogenital diaphragm. These superficial muscles provide uretheral support and may be superficial pelvic pain generators. The deep pelvic floor musculature is made up of two large muscles, the levator ani and the coccygeus. The levator ani is actually made up of a combination of three muscles, specifically the pubococcygeus, the puborectalis, and the iliococcygeus. A firm understanding of the anatomy of this region is paramount to fully appreciating the functional significance of these muscles. They are appropriately named for their attachments at the level of the coccyx and hence should be considered as potential sources of coccygeal pain, especially when the muscles are in a shortened state.

All of these muscles together form the pelvic floor which provides support for the intra-abdominal organs and prevents prolapse. Their combined optimal function as a neuromuscular unit is integral to maintaining urinary, flatal, and fecal continence. They also contract during orgasm to provide sexual appreciation. The pelvic floor muscles have a heightened role during pregnancy in maintaining functional support of the changing body habitus. They can be damaged at the time of labor and delivery and remain a persistent cause of pain.

When a pelvic obliquity is present, the resulting asymmetry affects the pelvic floor muscles that originate from and that are attached to the pelvic bones. With a pelvic obliquity, the attaching muscles will be either abnormally shortened or lengthened. A force–tension curve of these muscles will be shifted, thereby demonstrating their disadvantageous biomechanical state. As well, it is known that muscle injury and soreness are more selectively associated with eccentric contraction.15a-c An inherently lengthened muscle must also work harder to function properly, and if the external force on the muscular floor is greater than the force the muscles can generate, weakness may eventually develop in addition to or in conjunction with pain.

COCCYDYNIA

Coccydynia (synonymous with coccygodynia and coccyodynia) is defined as pain in and around the coccyx without significant symptom referral. Sitting or arising from the seated to standing position are common exacerbating influences. A prepartum history of coccyx pain or complaints of very low back pain or tailbone pain warrant consideration of this diagnosis in pregnancy. The coccyx is heavily supported by ligamentous structures and serves as the attachment point for pelvic floor musculature. The combination of laxity and asymmetry can create abnormal motion at the level of the coccyx similar to that of the SIJ. It is important to note that coccygeal pain may be secondary to pelvic floor muscle myofascial pain and dysfunction.

There is a blatant absence of literature guiding the evaluation of the coccyx in pregnancy; however, it can be easily done via rectal examination. A study by Maigne¹⁶ found that body mass index determines the manner by which a subject sits down and that pathologies were different in obese, normal weight, and thin patients. For a detailed description of the analyses in the nonpregnant patient the reader is referred to Chapter 120 by Yves Maigne. Hypermobility of the coccyx defined as coccygeal flexion exceeding 25° when the patient is in the sitting position as evaluated on plain radiograph was also a cause of coccydynia. The pregnant state lends itself to the potential of coccygeal dysfunction and pain with the acute increase of BMI over 9 months as well as ligamentous laxity that accompanies pregnancy as a result of relaxin and estrogen.

STRESS FRACTURE

Stress fracture is defined as fracture due to repetitive cyclic loading on normal bone, whereas insufficiency fracture occurs when normal forces are applied to abnormal bone. Stress insufficiency fracture occurs when repetitive cyclic loading occurs in the setting of abnormal bone. Any of these fractures at the level of the sacrum, pelvis, or hip may be the cause of back pain in the pregnant patient, similar to the nonpregnant patient. Fractures should be considered in a patient diagnosed with sacroiliac dysfunction which is not improving with medical rehabilitation and interventional spine techniques; in the case of known trauma; or in a patient with a prepartum history of amenorrhea, eating disorder, or known osteopenia (female athletic triad).¹⁷

Risk factors specific to pregnancy that predispose for sacral fatigue fractures include rapid or excessive weight gain in the third trimester, increased lumbar lordosis, pelvic instability due to relaxin effect, rapid vaginal delivery, and prolactin-induced transient osteopenia. These injuries should also be considered immediately postpartum in the breastfeeding patient. Polatti showed evidence of a progressive decline in bone mineral density (BMD) in lactating women over the first 6 months with increase in BMD following a 1-month weaning period.^17a Calcium supplementation during lactation had only a transient effect in minimizing bone loss.

The imaging study of choice in pregnancy after the first trimester when there is a high suspicion of stress fracture is magnetic resonance imaging. A comprehensive literature review revealed several reported sacral fractures associated with pregnancy.^18,19,19a

PUBIC SYMPHYSIS

LUMBAR DISC HERNIATION

Although early studies by LaBan et al. in 1983²⁴ suggested that pregnancy was an independent risk factor for the development of a herniated disc, it has been proven in subsequent studies that the actual incidence of lumbar herniated disc is no greater for pregnant women than for the general population.^2,4 It is an uncommon etiology of low back pain in pregnancy with an incidence of 1:10 000.²⁴ Risk factors include prior history of low back pain, increased body mass index, and lower socioeconomic status. Advanced maternal age, birth weight, and primiparity are controversial risk factors. In the last 20 years, the incidence of women aged 30 years and older at delivery has increased from 17.7% to 30.2%.^24a Since the inexorable alterations that occur as the degenerative disc cascade proceeds²⁵ will be more prominent as a female ages, it is expected that the probability of pain emanating from degenerative disc disease will be higher in this group. Pain from lumbar degenerative disc disease should be considered in the pregnant and nonpregnant patient alike who complains of back pain, numbness and tingling, or with neurologic findings on examination. A thorough examination is critical to differentiate the symptoms of degenerative disc disease from the radicular pain of a herniated disc from SIJ dysfunction. It is important to note that patients can have SIJ dysfunction concurrently with an S1 radiculopathy. If there is progressive weakness or bowel or bladder incontinence in pregnancy associated with back pain, cauda equina syndrome must be ruled out. Immediate imaging with MRI and surgical referral, even in pregnancy, is warranted.

NEUROLOGIC CAUSES OF BACK PAIN IN PREGNANCY

Neurologic sequelae in pregnancy may or may not be related to lumbar pathology. Nerve disorders that occur in the nonpregnant state can occur in pregnancy though they are not well described in the literature. Patients may experience direct nerve trauma or peripheral neuropathy from other disease states such as diabetes. Lateral femoral cutaneous neuropathy, or meralgia parasthetica, is a sensory abnormality of the anterolateral thigh and is the most common nerve injury seen in pregnancy.²⁶ This lesion can be seen in association with a pelvic obliquity (often a left innominate posterior rotation) and consequently in those with concomitant SIJ pain. Hence, early treatment of the pelvic obliquity may influence outcome and improve numbness. Although Wong et al. also described this as the most common immediate postpartum nerve injury, they found low incidences of nerve injuries in general (0.92%) after labor and delivery.²⁷

True sciatic nerve pathology is only seen in 1% of the pregnant population, despite its overuse as a catchall diagnosis for back pain or radiating pain in pregnancy.³ More comprehensive neurologic studies, such as needle electromyography and nerve conduction studies, may need to be done to diagnose a true sciatic nerve lesion versus an S1 radiculopathy or sacroiliac joint pain referred in a neurologic distribution.

CONCOMITANT CONDITIONS

EXAMINATION TECHNIQUES

Core stability examination

Testing of core strength is instrumental to overall proper body mechanics. In Akuthota and Nadler’s review of core strengthening in 2004,³³ the core is comprised of the diaphragm serving as the roof of the core, the pelvic floor and hip girdle musculature as the floor, the anterior and lateral abdominal musculature including the transversus abdominus and oblique muscles, and the posterior spine stabilizers including the erector spinae and multifidus and gluteals forming the posterior core. The relationship of these muscles is intimate; there is known co-activation of the pelvic floor muscles with transversus abdominus contraction.³⁴ These muscles serve to provide stability to the lumbar spine. In the pregnant state, the growing uterus dictates lengthening of the abdominal musculature, and consequent relative muscle contraction inefficiency. There is an increased demand of the lumbar erector spinae muscles to continually concentrically contract to maintain an erect posture. If the core is weak, this leads to muscle imbalances with compensatory mechanisms which may be contributing to the patient’s pain complaints. Core strength is frequently compromised in the pregnant and postpartum state. Childbirth is directly injurious to the pelvic floor muscles and can create significant transient weakness. Normal pelvic floor muscle strength generally returns within 2 month postpartum.³⁵ Simple tests to evaluation core strength in the pregnant patient include:

SUPINE BRIDGING: With the patient laying supine, her hips and knees are flexed and feet are placed flat on the table. Then, the patient lifts her buttocks off the table. Higher-level strength can be assessed by lifting the contralateral leg in a single-leg bridge position.

SINGLE-LEG STANCE WITH TRIPLANAR MOTION: Single-leg stance with triplanar reach tests may be an unfair assessment in the pregnant patient due to changes in the center of gravity which naturally compromise balance. Other static core strength tests are more feasible in the pregnant patient as described above.

ABDOMINAL MUSCULATURE: Assessment of the integrity of the rectus abdominus is important in the pregnant patient. Diastasis is a common physical finding in pregnancy with increasing growth of the gravid uterus. Although this is typically not a pain generator, a defect anteriorly, especially in conjunction with weakness of pelvic floor muscles, can theoretically lead to muscle imbalance and predispose the pregnant patient to lumbar injury (Fig. 123.1).

Fig. 123.1 Evaluation of rectus diastasis: place two fingers in the periumbilical region to palpate separation of the rectus abdominus. You may accentuate the separation with an abdominal crunch. Separation is described in centimeters; one centimeter is roughly equivalent to one finger breadth.

Pelvis and sacroiliac joint examination

Physical examination focused on detecting aberrant motion of the SIJ is notoriously unreliable. A study by Dreyfuss et al.³⁶ in 1996 evaluated 12 common testing maneuvers for SIJ pain and found that none of the 12 tests was able to reliably detect SIJ dysfunction in 85 patients. However, this study did not include the pregnant population. Another study by Albert et al.³⁷ in 2000 specifically looked at pregnant patients and found that in patients with sacroiliac joint pain three tests had superior sensitivity: the posterior pelvic pain provocation test, Menell’s test, and FABER test, despite reasonable reliability of several other physical examination maneuvers. In 1994, Laslett concluded that five of seven tests were reliable in predicting the sacroiliac joint as a pain source, and that the remaining two tests were potentially reliable.³⁸ In 2003, Young et al. again validated the significant correlation between clinical examination findings with 3 or more pain provocation tests and SIJ pain.³⁹ In 2003, Laslett et al. further showed that the diagnostic accuracy of the physical examination was superior to sacroiliac joint pain provocation test alone for diagnosing symptomatic SIJ.⁴⁰ Uniform in all of these studies, inter-tester reliability is critical. Practice with these tests and performing them consistently each time will help proper diagnosis of sacroiliac joint dysfunction.

Palpation and mobility testing of the sacroiliac joint

ALIGNMENT: Iliac crest, PSIS, ASIS: With the patient standing, the examiner notes the heights of both iliac crests and each PSIS. The ASIS may be assessed in standing or supine. If the anterior and posterior iliac spines are at the same level, the pelvis is considered to be in proper alignment. If not, the pelvis is misaligned – either anteriorly rotated, posteriorly rotated or sheered superiorly or inferiorly.³⁷

PALPATION OVER THE SIJ: Positive test is if there is sacral sulcus tenderness immediately medial to the posterior superior iliac spine.³⁶ Palpation in this area approximates the sacroiliac joint line.

GILLET’S TEST: The examiner has the patient stand with his or her feet 12 inches apart, while the examiner sits behind the patient and palpates the bilateral posterior superior iliac spines. The patient then flexes the knee and hip on the side to be tested (Fig. 123.2). ‘Stand on one leg and bring the other leg to your chest,’ is often the direction given. The test should show movement of the PSIS inferiorly or a ‘drop’ of the PSIS is seen on the ipsilateral side of the lifted leg. If there is no drop, the test is positive for hypomobility on that side, but is not correlated to the side of pain.³⁶

Fig. 123.2 Gillet’s test to assess left SIJ motion.

PALPATION OF PUBIC SYMPHYSIS: With the patient lying supine, the pubic symphysis is palpated gently. If palpation causes pain, that is a positive sign for pubic symphysis tenderness.³⁷

Provocative testing of the sacroiliac joint

FABERS TEST: With the patient lying supine, the patient’s hip is Flexed, ABducted and Externally Rotated so that the heel rests on the opposite kneecap. Pain may be experienced in the inguinal region, which suggests hip joint pathology. Pain may also be experienced in the back or SIJ, suggesting SIJ dysfunction.³⁷ This test is also known as the figure-4 test and Patrick’s maneuver.

FORCED FABER’S TEST: This is another maneuver more specific for SIJ pathology. With the patient in the same position as above, anterior to posterior force is placed on both the externally rotated leg at the knee and on the opposite ASIS (Fig. 123.3). This test is positive with production of pain in the SIJ.³²

Fig. 123.3 Faber’s maneuver to test right-sided SIJ dysfunction.

GAENSLEN’S TEST: With the patient lying supine and on the edge of the examination table, one hip and knee are flexed and held by the patient, while the other hip is extended off the side of the table. Overpressure exerted on the extended knee is applied to force the sacroiliac joint to its end range.³⁸ This test can be performed in the side-lying position with the patient holding the lower leg flexed against the chest while the uppermost leg is extended.³²

MENELL’S TEST: With the patient lying supine, one hip is moved into 30° abduction and 10° flexion. It is then first pushed into, then pulled out from the pelvis causing sagittal movement. Pain is considered positive for this test.³⁷

POSTERIOR PELVIC PAIN PROVOCATION TEST (OR AP GLIDE): With the patient lying supine, the hip is flexed to be perpendicular with the table at 90° and the knee is flexed at 90°. A gentle force is applied to the femur in the direction of the examination table, from anterior to posterior (Fig. 123.4). The test is positive when the patient experiences pain in the gluteal region of the tested leg.^37,41

Fig. 123.4 Posterior pelvic provocation test (AP glide) to test right-sided SI joint dysfunction.

ACTIVE STRAIGHT LEG RAISE (ASLR) TEST: This test is performed with the patient supine with both legs extended on the table. The patient raises one leg at a time to 30° of hip flexion without flexing the knee. The test is considered positive when the patient has pain in the back with the leg raised, or describes a heaviness or difficulty in performing the task.^42,43 In the second part of the maneuver, posterior compression is applied and the patient is then asked to actively perform a straight leg raise (Fig. 123.5). If there is less pain upon compression or greater ease in motion this is considered a positive provocative test.

Fig. 123.5 Active straight leg raise with compression to test right-sided SIJ dysfunction.

COMPRESSION TEST: With the patient supine, pressure is placed on both sides of the pelvis at the ASIS with force applied inward by the palms of the examiner’s hands.³⁸

Although there is no literature describing its use as an aid in examination, the use of an SIJ belt may be helpful. Similar to the compression test described above, the SIJ belt can be applied to provide a compressive force about the pelvis. The ASLR is then repeated to see if the patient’s pain is reduced. If these tests are positive, it suggests the SIJ may be the putative pain generator. This will then help guide prescription and application of an SIJ belt in treatment of SIJ pain.

DIAGNOSTIC WORK-UP

In 1997, the National Council on Radiation Protection and Measurements (NCRP) evaluated the effects of all types of radiation on reproduction. Many articles were presented which discussed the effects of irradiation on the developing fetus, including congenital malformation, growth retardation, pregnancy loss, and mental retardation.^48,49 Although there is argument over the amount of irradiation that would produce such effects, it is generally thought that avoidance of such exposures for the pregnant patient is the rule. However, the failure to correctly diagnose maternal medical problems may pose a much greater risk to the fetus. One paper proposed guidelines for single radiographic image of the abdomen or pelvis with the fetus in field of view as well as estimated fetal dose for CT of the abdomen or pelvis with the fetus in field of view.⁵⁰ Despite these guidelines, practitioners generally associate exposure to roentgenograms or abdominal CT with high risks to the developing fetus.⁵¹

Ultrasound, on the other hand, has been used clinically as an effective diagnostic tool in pregnancy for many years. To date, there is no documented evidence of fetal harm from ultrasound.⁵¹ Technological advances have significantly improved, intra-abdominal, intrapelvic and fetal assessments, but because sonography cannot penetrate bone, intra-osseous, epidural, intrathecal and discogenic disease cannot be adequately evaluated. It is limited in its ability to diagnose more sinister etiologies of back or pelvic pain in pregnancy.

Magnetic resonance imaging does not use any ionizing radiation and therefore is thought to be safe for use in the pregnant patient. Until recently, MRI in the pregnant patient was used in the evaluation of adnexal masses, pelvimetry, hydroureteronephrosis of pregnancy, and placenta accreta and to evaluate fetal anomalies such as arachnoid cysts and ventriculomegaly.⁵³ Fast MRI has essentially done away with the need for sedation of the mother and fetus to prevent fetal movement artifact.⁵⁴ Fast MRI taken during suspension of maternal breathing removes this artifact and results in excellent images with high resolution.⁵⁵ Gadolinium is not recommended during pregnancy because of its ability to cross the placental barrier and potentially cause harm to the fetus.⁵⁵ Although MRI appears safe in pregnancy, the International Radiation Protection Association takes the position that MRI should be postponed until after the first trimester and should be limited to cases where unique diagnostic information can be obtained.⁵⁵ Fast MRI has expanded its usefulness to evaluate and diagnose nonpregnancy-related conditions in the pregnant patient such as lumbar disc herniations and pelvic stress fractures. It can also be used in patients with both posterior and anterior pelvic pain postpartum. One study demonstrated increased T-weighted signal change consistent with edema of the pelvic joints in those with pain.⁵⁶

Ultrasound would seem to be an excellent tool to use diagnostically to evaluate the SIJ in the pregnant patient; however, there are no published studies to date.

SIJ injections have been used as a diagnostic tool for potential sacroiliac joint-mediated pain. There is literature suggesting a low success rate of blindly placing medications intra-articularly within the sacroiliac joints.⁵⁷ In contrast, there is evidence that medications can be successfully placed within the SIJ using CT guidance⁵⁸ or fluoroscopic guidance.⁵⁹ It has been shown that sacroiliac joint injections are clinically effective for the diagnosis and treatment of SIJ syndrome. Because the pregnant population should not undergo fluoroscopy or CT, Pekkafal, in 2003, studied SIJ injections performed under sonographic guidance.⁶⁰ Of the 60 sonographically guided SIJ injections they performed, 76% were successfully placed intra-articularly and 23% were missed. More importantly, the last 30 injections that were performed had a success rate of 94%, suggesting a significant training effect. Although these were not performed specifically in the pregnant population, the use of ultrasound during pregnancy is known to be safe and the obvious utility of this intervention is important. Future studies should be aimed at the use of ultrasound guided intra-articular SIJ injections for both the diagnosis and treatment of SIJ dysfunction in the pregnant women.

Needle electromyography and nerve conduction studies can be used in pregnancy for evaluation of a radiculopathy. There are no data that such testing is contraindicated in pregnancy.

CONCLUSIONS

Disabling back pain in the pregnant patient warrants meticulous and detailed physical examination and appropriate diagnostic work-up in light of limited radiographic options. Differential diagnoses include disorders commonly seen in the nonpregnant population with an emphasis on pelvic obliquity and associated SIJ dysfunction. Subsequent therapeutic options are based on comprehensive assessment (Fig. 123.6). Low back pain in pregnancy is manageable and treatable if a proper and timely diagnosis is reached.

Fig. 123.6 Algorithm for low back pain in pregnancy.