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The purpose of this study was to investigate the clinical and radiological features of osteoporotic burst fractures affecting levels below the second lumbar (middle-low lumbar) vertebrae, and to clarify the appropriate surgical procedure to avoid postoperative complications. Thirty-eight consecutive patients (nine male, 29 female; mean age: 74.8 years; range: 60-86 years) with burst fractures affecting the middle-low lumbar vertebrae who underwent posterior-instrumented fusion were included. Using the Magerl classification system, these fractures were classified into three types: 16 patients with superior incomplete burst fracture (superior-type), 11 patients with inferior incomplete burst fracture (inferior-type) and 11 patients with complete burst fracture (complete-type). The clinical features were investigated for each type, and postoperative complications such as postoperative vertebral collapse (PVC) and instrumentation failure were assessed after a mean follow-up period of 3.1 years (range: 1-8.1 years). All patients suffered from severe leg pain by radiculopathy, except one with superior-type fracture who exhibited cauda equina syndrome. Nineteen of 27 patients with superior- or inferior-type fracture were found to have spondylolisthesis due to segmental instability. Although postoperative neurological status improved significantly, lumbar lordosis and segmental lordosis at the fused level deteriorated from the postoperative period to the final follow-up due to postoperative complications caused mainly by PVC (29%) and instrument failure (37%). Posterior-instrumented fusion led to a good clinical outcome; however, a higher incidence of postoperative complications due to bone fragility was inevitable. Therefore, short-segment instrument and fusion with some augumentation techniqus, together with strong osteoporotic medications may be required to avoid such complications.

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OBJECTIVE: Low lumbar osteoporotic vertebral collapse (OVC) has not been well documented compared with OVC of the thoracolumbar spine. The differences between low lumbar and thoracolumbar lesions should be studied to provide better treatment. The aim of this study was to clarify the clinical and imaging features as well as outcomes of low lumbar OVC and to discuss the appropriate surgical treatment. METHODS: Thirty patients (10 men; 20 women; mean age 79.3 ± 4.7 years [range 70-88 years]) with low lumbar OVC affecting levels below L-3 underwent surgical treatment. The clinical symptoms, morphological features of affected vertebra, sagittal spinopelvic alignment, neurological status before and after surgery, and surgical procedures were reviewed at a mean follow-up period of 2.4 years. RESULTS: The main clinical symptom was radicular leg pain. Most patients had old compression fractures at the thoracolumbar level. The affected vertebra was flat-type and concave or H-shaped type, not wedge type as often found in thoracolumbar OVC. There were mismatches between pelvic incidence and lumbar lordosis on plain radiographs. On CT and MR images, foraminal stenosis was seen in 18 patients (60%) and canal stenosis in 24 patients (80%). Decompression with short fusion using a posterior approach was performed. Augmentations of vertebroplasty, posterolateral fusion, and posterior lumbar interbody fusion were performed based on the presence/absence of local kyphosis of lumbar spine, cleft formation, and/or intervertebral instability. Although the neurological and visual analog scale scores improved postoperatively, 8 patients (26.7%) developed postoperative complications mainly related to instrumentation failure. In patients with postoperative complications, lumbar spine bone mineral density was significantly low, but the spinopelvic alignment showed no correlation when compared with those without complications. CONCLUSIONS: The main types of low lumbar OVC were flat-type and concave type, which resulted in neurological symptoms by retropulsed bony fragments generating foraminal stenosis and/or canal stenosis. For patients with low lumbar OVC, decompression of the foraminal and canal stenosis with short fusion surgery via posterior approach can improve neurological symptoms. Since these patients are elderly with poor bone quality and other complications, treatments for both OVC and osteoporosis should be provided to achieve good clinical outcome.

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The low lumbar spine is deeply located in flexible segments, and has a physiologic lordosis. Therefore, burst fractures of the low lumbar spine are uncommon injuries. The treatment for such injuries may either be conservative or surgical management according to canal compromise and the neurological status. However, there are no general guidelines or consensus for the treatment of low lumbar burst fractures especially in neurologically intact cases with severe canal compromise. We report a patient with a burst fracture of the fourth lumbar vertebra, who was treated surgically but without fusion because of the neurologically intact status in spite of severe canal compromise of more than 85%. It was possible to preserve motion segments by removal of screws at one year later. We also discuss why bone fusion was not necessary with review of the relevant literature.

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The low lumbar spine is deeply located in flexible segments, and has a physiologic lordosis. Therefore, burst fractures of the low lumbar spine are uncommon injuries. The treatment for such injuries may either be conservative or surgical management according to canal compromise and the neurological status. However, there are no general guidelines or consensus for the treatment of low lumbar burst fractures especially in neurologically intact cases with severe canal compromise. We report a patient with a burst fracture of the fourth lumbar vertebra, who was treated surgically but without fusion because of the neurologically intact status in spite of severe canal compromise of more than 85%. It was possible to preserve motion segments by removal of screws at one year later. We also discuss why bone fusion was not necessary with review of the relevant literature.

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A retrospective review of 14 patients treated non-operatively or operatively for burst fractures of the low lumbar spine(L4-L5) between January 1992 and December 1997 was performed. Burst fractures of the low lumbar spine are rare and have not been well delineated in the literature. Average follow-up period for fourteen patients was 10.6 months. Ten patients were men and four were women. The average age at injury was 36.8 years(range 17-70 years). Seventy-one percent of the injuries were the result of fall from height and 29% were the result of motor vehicle accidents. Non-operatively treated six patients were presented with minimal canal compromise and minimal or no initial neurological deficit. They were treated 4-6weeks of bed rest before they were allowed to mobilize with orthosis. None of these patients had any significant complications. If patients showed neurological impairment associated with significant canal compromise or vertebral height loss, they were treated operatively to restore spinal stability and spinal height and also to decompress neural elements. Various types of combined surgical approaches were used for eight patients who met these criteria. Among these, two were treated in a staged fashion with the anterior transperitoneal approach done initially. Vertebrectomy and complete neural decompression in direct vision was possible and interbody fusion was performed using Mesh cage, which was filled with bone collected from sites of vertebrectomy. This combined approach seems to be the choice of procedure for complete decompression and interbody fusion of the low lumbar burst fracture(L4-L5) with severe canal compromise and vertebral height loss. Transperitoneal approach for the low lumbar vertebrectomy has advantage of less muscular damage compared to retroperitoneal approach. There were no major complications from surgery in the present series.

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