Bilateral pedicle stress fracture in the lumbar spine of a sedentary office worker.

A case of bilateral pedicle fracture in the lumbar spine of a sedentary office worker is being presented. No such case has been reported in the literature previously. Bilateral pedicle fracture is a rare entity. Few cases have been reported in literature. All the reported cases had some underlying causative factors like degenerative spine disease, previous spinal surgery or stress-related activities, e.g. athletes. Our case is a 36-year-old sedentary office worker with none of the factors mentioned. We present a case of a 36-year-old sedentary worker with long-standing low backache. There were no root tension signs. Plain radiographs were inconclusive. The patient had a CT scan. The CT scan revealed long-standing defects in the pedicles of L2 vertebra with pseudoarthrosis. Infiltration with anaesthetic relieved the symptoms. Our patient was managed conservatively with spine rehabilitation physiotherapy program. Pedicle fracture can develop due to abnormal stresses in the pedicle either because of previous spinal surgery or spondylitic changes in the spine. Bilateral pedicle fracture in the absence of these conditions is extremely rare.

Introduction

Isolated pedicle fracture in the spine is uncommon. It has been reported in association with previous spine surgery, or in highly active athletic individuals. We report a case of bilateral pedicle fracture in a patient with chronic backache without the history of trauma or any of the above-mentioned conditions. The patient was a sedentary worker with minimal physical demands.

Case report

We present a case of a 36-year-old female with a history of chronic backache. Her symptoms were of mild to moderate in intensity. Discomfort was mainly related to activity but she was performing her normal duties as an office manager without significant problems. On examination there were no neurological deficit or root tension signs. Plain radiographs were inconclusive. Clinical examination revealed localized deep tenderness at L2; therefore, a CT scan was performed. The CT scan showed bilateral long-standing defects through the pedicles of 2nd lumbar vertebra with pseudoarthrosis and sclerosis (Fig. 1a, b). Infiltration with local anaesthetic, under the X-ray guidance, in the involved area relieved the symptoms. Surgical management was discussed with the patient, which was declined. The patient underwent spine rehabilitation physiotherapy program, which resulted in the improvement of the symptoms.

Fig. 1

a CT scan of the vertebra showing bilateral pedicle fracture. b CT scan showing bilateral pedicle fracture with pseudoarthrosis

Discussion

Bilateral pedicle stress fracture in the spine is a rare finding. Traughber and Havlina [10] reported the first case of a bilateral pedicle stress fracture. Cyron et al. [2] demonstrated that the parsintereticularis is thought to be the weakest site in the neural arch, followed by the pedicle. In cases with established unilateral stress fracture, there is a redistribution of forces in the neural arch, which leads to compensatory sclerosis of contralateral bony structures. A compensatory hypertrophy of the contralateral pedicle has been documented [1, 8]. This entity was first described by Wilkinson and Hall [11] in 1974. These authors reported on seven patients whose radiographs were suspicious for a neoplastic process occurring in a pedicle (e.g. osteoid osteoma or osteoblastoma). Further investigation revealed unilateral spondylolysis with sclerosis of the contralateral posterior elements. The incidence of bilateral pedicle stress fracture is unknown in an otherwise normal spine. Gunzburg and Fraser [3] introduced the term pediculolysis in 1991 in a patient with multilevel facet joint osteoarthritis and minimal spondylolisthesis at L4–L5. Pedicle fracture has been reported in cases following posterolateral instrumented spinal fusion [4, 5, 7]. Bilateral pedicle stress fractures or pediculolysis have been documented in an athlete of high physical demand [6]. Stanley and Smith [9] reported a case of pedicle fracture following laminectomy. In our patient the fractures appear to be old with evidence of sclerosis at the fracture margins along with pseudoarthrosis. This type of bilateral pedicle stress fracture has not been documented in a normal spine of a sedentary office worker without a history of major trauma or surgery.

Conclusion

Pedicle fracture is uncommon but has been reported in association with degenerative spondylolisthesis, unilateral spondylolysis, following spinal surgery but not in an otherwise normal spine. Pedicle stress fracture may show either as a recent fracture or may have signs of established pseudoarthrosis. So far there is no case of bilateral pedicle stress fracture in an otherwise normal spine.