Not Another Back Pain in Pregnancy!

Abstract

The patient is a 35-year-old G2P1001 who presented at 24-4/7 weeks by first-trimester ultrasound with 1 week of worsening left lower back and gluteal pain. Initially the pain was minimally improved with conservative treatment of muscle relaxants, acetaminophen, heat, ice, and rest, but over the 24 hours before admission, the pain had increased such that the patient could no longer ambulate, and she had not urinated the day of presentation. She described the pain as a constant spasm, with nothing relieving it, and moving making it worse. The patient states that she had had tightness in the area for several weeks but awoke with the pain 1 week before admission. She also had developed a second-degree burn over the area of pain secondary to local diathermy application. She denied radiation of the pain, motor or sensory changes, or incontinence. Her medical history was significant only for an uncomplicated spontaneous vaginal delivery approximately 1 year ago. Antepartum course to date had been uncomplicated, with normal labs at the first obstetric visit. Her examination on admission was significant for a temperature of 98.6°F, blood pressure 110/63 mm Hg, pulse 82 beats/min, respirations 16 breaths/min, fetal heart tones of 160, and no contractions on tocometer. Her fundal height was 23 cm, and the cervix was long and closed. She had localized tenderness to palpation over the left posterior superior iliac spine (PSIS), piriformis and gluteus minimus, and a 6 ϫ 8-cm second-degree burn with skin breakdown in the left lower quadrant of the burn. She had normal sensation, proprioception and deep tendon reflexes of her lower extremities bilaterally, and a negative straight leg raise.Initial laboratory values included white blood count of 7.4 ϫ 10 3 (74% segs), hemaglobin 11 g/dL, hematocrit 32%, platelets 234 ϫ 10 3 , and a urinalysis that was negative.The patient was initially diagnosed with spasm of the piriformis muscle and treated with antiinflammatories, muscle relaxants, and narcotics. A Foley catheter was placed and she had 1000 mL of retained urine. Manipulative therapy was also used; all treatments had provided minimal relief. The next day, the patient was seen by the pain service. A trigger point on the left piriformis was injected with 9 mL of 2% lidocaine with bicarbonate without relief. On further examination, a bony or joint pain syndrome was suspected as a result of the severe pain caused by internal and external rotation of the femur and loading of the femur and iliac crest. The patient remained unable to move without severe pain, and she received no relief with scheduled or patient-controlled analgesic narcotics.The evening of hospital day 2, the patient had a magnetic resonance image, which was significant for increased bone marrow signal intensity in the left posterior superior iliac spine (PSIS) on the T2weighted images, and decreased signal intensity on the T1-weighted images. She was seen by the orthopedics service, who recommended a biopsy of the left PSIS. This was performed in the operating room t...