Article
Figure 4 . Two sagittal MRI views showing rupture of posterior elements at T9-T10 with high signal intensity and abnormal intracanal tissue compressing the spinal cord.
Figure 5 . Post-revision surgery p-a (a) and lateral (b) x-ray. The fusion was extended to T2 with decompression at T9-T10, using bi- lateral pedicular screws augmented with ce- ment at T2, T3, T4, T5 and T6. Satisfactory profile in both frontal and sagittal planes were obtained.
bar fusion. We are aware of only two studies1,5
as-
sessing the value of vertebral augmenta- tion as a prophylactic tool in the elderly or osteoporotic patients undergoing extended lumbar spine fusion; Hart et al.1
hypoth-
esised that routine prophylactic vertebral augmentation is cost-effective in patients older than 60 years undergoing extended lumbar fusions ending craneally within the thoracolumbar junction in comparison to the costs of revision surgery for patients suffering from proximal junctional acute collapse cranial to a multi-level lumbar fu- sion. Watanabe et al.6
describe two groups of
adult patients with proximal vertebral frac- tures following spinal deformity surgery using segmental pedicle screw instrumen- tation without cement augmentation: upper instrumented vertebral collapse + adjacent vertebral subluxation and those with su- pra-adjacent vertebral fracture alone. The first group presented a shorter interval be- tween the initial surgery and the fracture, hypokyphosis in the thoracic area before primary surgery and 40% had a severe neurologic deficit. Those authors proposed several risk factors for proximal junctional fracture: old age, osteopenia, severe global imbalance and marked correction of sagit- tal malalignment6
. In this paper, we report a case of ver-
tebral collapse at the upper instrumented level with adjacent vertebral subluxation after thoracolumbar fusion with augmen- tation at both levels, hypothesise about the possibility of an increased risk of this complication due to the effects of the ver- tebral augmentation and alert the orthope- dic community about this phenomenon.
Case presentation A 70-year-old woman with degenerative lumbar scoliosis suffering severe low back pain and neurogenic claudication, aggra- vated during ambulation, underwent de- compressive laminectomy at L4-L5 and posterolateral fusion with a reasonably good result. Four years later, her condition had worsened including neurogenic clau- dication and low back pain. Her primary care doctor referred her to our service as a new patient. At this point, the x-ray (Fig- ure 1) and MRI showed a left lumbar curve with a 34ª Cobb angle between T11 and L4, anterolateral lysthesis at L2-L3-L4-L5 and central and subarticular lateral recess stenosis. We used titanium 5.5 mm fenes- trated pedicular screws (Expedium, DePuy Spine, Raynham, MA, USA) on both sides at each level from T10 to S1 and an iliac screw in the right side (Figure 2), aug- mented with cement at T10, T11, L1, L5 and S1 (Confidence Spinal Cement Sys- tem, DePuy Spine, Raynham, MA, USA)
and prophylactic vertebroplasty at T9 to avoid the “topping-off syndrome”. There were no intraoperative pedicular fractures and special care was taken to preserve the structures of the tension band (posterior ligaments, facet joints, multifidi muscles) in the segment above the instrumentation. The patient had a torpid postoperative
recovery, complaining of pain in the tho- racolumbar area, but her ability to perform different physical activities increased dai- ly. The x-ray on day 3 post-surgery showed no abnormal finding. She was discharged walking 8 days after surgery. One month after discharge, without recognisable inciting trauma, the patient complained of increasing spontaneous pain in the lower thoracic area and neu- rological impairment in the lower limbs. Physical examination revealed tenderness in the lower thoracic spine without a pal- pable defect between the posterior spinous processes. Neurological examination was abnormal without associated injuries. The motor exam revealed an overall decrease in lower limbs muscle strength (2/5 on the left leg, and 3/5 on the right leg) with in- ability to walk, and response in the patel- lar and Achilles reflexes was increased,
32 | SpinalSurgeryNews | Autumn 2012
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