Posterior Stabilization Without Neural Decompression in Osteoporotic Thoracolumbar Fractures With Dynamic Cord Compression Causing Incomplete Neurological Deficits

Abstract

Study design: Prospective cohort study.

Objectives: Management of osteoporotic vertebral compression fracture (OVCF) remains an unsolved problem for a spine surgeon. We hypothesize that instability at the fracture site rather than neural compression is the main factor leading to a neurological deficit in patients with OVCF.

Methods: In this study, the prospective data of patients with osteoporotic fractures with incomplete neurological deficits from January 2015 to December 2017 was analyzed in those who underwent posterior instrumented fusion without neural decompression.

Results: A total of 61 patients received posterior indirect decompression via ligamentotaxis and stabilization only. Of these 17 patients had polymethylmethacrylate (PMMA) augmented screws and in 44 patients no PMMA augmentation was done. The mean preoperative kyphosis was 27.12° ± 9.63°, there was an improvement of 13.5° ± 6.87° in the immediate postoperative period and at the final follow-up, kyphosis was 13.7° ± 7.29° with a loss of correction by 2.85° ± 3.7°. The height restoration at the final follow-up was 45.4% ± 18.29%. In all patients, back pain was relieved, and neurological improvement was obtained by at least 1 American Spinal Injury Association Impairment Scale in all except 3 patients.

Conclusion: We propose that neural decompression of the spinal cord is not always necessary for the treatment of neurological impairment in patients with osteoporotic vertebral collapse with dynamic mobility. Dynamic magnetic resonance imaging is a valuable tool to make an accurate diagnosis and determine precise surgical plan and improving the surgical strategy of OVCF.

Keywords: neurological deficit; osteoporosis; thoracolumbar; vertebral compression fracture.

Figure 1.

Flowchart: selection and inclusion of patient data set.

Figure 2.

Representative image showing flexion (A) and extension (B) protocol of dynamic magnetic resonance imaging (MRI) of thoracolumbar spine. (C) Wedge-shaped bolster used for positioning in dynamic MRI.

Figure 3.

Dynamic lateral radiographs (flexion—A; extension—B) showing osteoporotic fracture of T12 vertebra with dynamic spinal cord compression seen on dynamic magnetic resonance imaging (flexion MRI—C; extension MRI—D). Spinal compression due to bony protrusion into the canal on flexion and restoration of cerebrospinal fluid column in extension can be appreciated.

Figure 4.

(A) Method of Leiberman: % height improvement = postkyphoplasty % (2/1 × 100) – prekyphoplasty % value (2/1 × 100) ÷ 100% − prekyphoplasty % value. (B) Cobbs method for measuring focal kyphosis angle, angle between superior end plate of upper normal vertebra and inferior end plate of lower normal vertebra.

Figure 5.

Radiographs (A, B) and computed tomography (CT) scans (sagittal—C; axial—D) of a 61-year-old woman with fracture T12 with incomplete neurology with canal compromise evident on CT and neutral magnetic resonance imaging (MRI) (E). The dynamic nature of compression on spinal cord can be appreciated on flexion MRI (F) and canal clearance on extension MRI (G). Immediate postoperative images (H, I) and 2-year follow-up images (J, K) showing cement augmented long segment fixation.

Figure 6.

An 80-year-old man with flexion magnetic resonance imaging (MRI) (A) and X-ray lateral (B) image showing osteoporotic vertebral compression fracture (OVCF) T11 vertebra with retropulsion of bone fragment and dynamic cord compression with American Spinal Injury Association (ASIA) grade C neurology. Immediate postoperative X-rays (C, D) showing cement augmented long-segment fixation of D9-L1 and vertebroplasty of fracture D11 vertebra with postoperative MRI image (E) showing adequate cord decompression. Failure of instrumentation at distal end at 1-year follow-up (F, G) and extension of construct up to L2 using dominoes (H, I).

Figure 7.

A 65-year-old man with American Spinal Injury Association (ASIA) grade C neurology with D11 vertebral fracture with intravertebral cleft seen on X-ray (A, B) and magnetic resonance imaging (MRI), sagittal (C) and axial (D) section with cord compression due to repulsion of bone fragments and old healed osteoporotic fracture L1 and L4. Immediate postoperative images showing long-segment fixation from D9 to L1. At latest follow-up at 2 years, the patient had rod breakage with recollapse of D11 vertebral segment with loss of correction. Patient improved neurologically to ASIA grade E.