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Nonoperative Treatment of Thoracolumbar Burst Fractures PDF Print E-mail

Joel A. Finkelstein, M.D., FRCSC
Assistant Professor, Department of Surgery, University of Toronto
Division of Orthopaedics, Sunnybrook and Women's College HSC
Sunnybrook Spine Programme

In the management of spinal trauma, there isn't an entity that has been a greater source of debate than the thoracolumbar "burst fracture". Before embarking on the virtues of non-operative management for thoracolumbar burst fractures, it would be best to define what the subject of the debate is; are we debating management of the stable fracture pattern, or the unstable fracture pattern? Furthermore, what is a stable as opposed to an unstable fracture? This, in my opinion, is the bigger controversy that needs to be resolved.  

For purposes of this forum, we are discussing the neurologically intact patient. Issues surrounding incomplete and complete spinal cord or cauda equina injury present a separate set of considerations. In the intact patient, treatment is directed at management of mechanical instability of the spine.

What is a Burst Fracture?
To answer this, there needs to be an understanding of the three-column theory of the spine. Holdsworth initially described the two-column concept of the spine. The anterior column compri-ses the anterior half of the vertebral body. This column resists compressive loads. The posterior column comprises the facet joints and the interspinous ligaments. This column acts as the tension band and resists distractive loads. It is the posterior column that is most important in providing stability to the spine.

The third column is the middle column. Denis developed the concept of the middle column of the spine, the posterior half of the vertebral body, for the sole purpose of defining the burst fracture1. The middle column has no significant value for biomechanical stability (Figure 1).

Figure 1

By definition, the burst fracture is a fracture that involves the middle column. The middle column must fail in compression. Radiographically there is loss of height of the posterior vertebral body wall, there is variable (and most commonly) retropulsion of bone and widening of the interpedicular distance. In the intact patient, regardless of middle column involvement, treatment is determined by the stability of the fracture.

Stability
The concept of stability needs to be defined. White and Panjabi define stability as the ability of the supporting elements of the spine to resist physiological loads so as to prevent neurological injury, deformity and pain11. I like to qualify 'unstable' as being either absolute or relative. An absolutely unstable spine is one where if the patient is not protected by way of spine precautions, an injury to the neural elements is likely. Additionally, an acute kyphosis and/or a painful deformity is certain. The role of operative management in this situation is clear. Surgery would be required to reduce the current deformity, and stabilize and fuse the spine in a position that would not be expected to lead to late pain. An anatomical alignment is desirable.

A relatively unstable fracture is an injury pattern, which may not lead to an acute catastrophic event to the patient if he is mo-bilized (preferably with a brace), but can be expected to lead to a poor functional outcome due to pain and late deformity. Various parameters have been used to suggest this type of instability:

1) A kyphosis of 20-25°
2) Greater than 40% loss of vertebral body height
3) Posterior column involvement (this may also indicate absolute instability).

Post–traumatic kyphosis leads to back pain and a poor functional outcome. Pain can arise at the specific site of the deformity or at the lower lumbar spine. The lower lumbar levels will hyperlordose in an effort to maintain overall sagittal balance. This can cause overloading of the facet joints and muscular pain. The role of surgery again is clear in this relatively unstable fracture. The goal of surgery is again to reduce the deformity, stabilize and fuse the spine in a near anatomical alignment.

The Stable Burst
A stable injury is one where fracture pattern is not sufficient to disrupt the overall ability of the spinal elements to resist further deformity. The spine is at no risk of injuring the neural elements. The alignment, when healed, would not in itself lead to pain. There is ample evidence that conservative treatment provides good outcomes in this situation1,2,3,4,8. Furthermore, a number of studies have repeatedly found that operative treatment of patients with a stable thoracolumbar burst fractures provided no major long-term advantage compared with nonoperative treatment.7,9,10.

Treatment of the Stable Burst Fracture
The method and length of bracing may be disputed as well as the belief by some surgeons that an initial period of bed rest should be imposed. It is my practise to treat these injuries with a TLSO for a total of 12 weeks with early ambulation. Serial upright radiographs are taken immediately after the brace is in place, at two weeks, six weeks and 12 weeks. Walking is encouraged and instruction is given to exercise the antigravity muscles of the upper back and shoulders. If an unacceptable collapse is noted (usually by two weeks), then re-evaluation of the injury is made, as a relatively unstable fracture may be present. It is also not uncommon for these progressive deformities to be a misdiagnosed flexion-distraction injury with posterior column disruption. Hence, an accurate diagnosis is critical from the outset. Surgery is now indicated if the degree of deformity suggests that there will be an unacceptable post-traumatic kyphosis. Surgical treatment can be delayed until two to three weeks without losing ability to effect a good correction of the deformity.

The Last Word
What degree of deformity portends to a poor outcome is now the crucial question. It has been my practise to operate on fewer and fewer burst fractures. Results from the Scoliosis Research Society's multicentre spine fracture study showed that only when patients had a greater than 30° of final kyphosis was there an increased incidence of back pain at two years.6 I have similarly found that if final kyphosis at the end of conservative treatment is less than 30°, the outcome of nonoperative management is excellent.

References

  1. Aligizakis A., Katonis P., Stergiopoulos K., Galanakis I., Karabekios S., Hadjipavlou A. Functional outcome of burst fractures of the thoracolumbar spine managed non-operatively, with early ambulation, evaluated using the load sharing classification. Acta Orthop Belg. 2002;68:279-87.

  2. Cantor J.B., Lebwohl N.H., Garvey T., Eismont F.J. Nonoperative management of stable thoracolumbar burst fractures with early ambulation and bracing. Spine 1993; 18: 971-6.

  3. Chan D.P., Seng N.K., Kaan K.T. Nonoperative treatment in burst fractures of the lumbar spine (L2-L5) without neurologic deficits. Spine. 1993;18:320-5.

  4. Chow G.H., Nelson B.J., Gebhard J.S., Brugman J.L., Brown C.W., Donaldson D.H. Functional outcome of thoracolumbar burst fractures managed with hyperextension casting or bracing and early mobilization. Spine. 1996; 21:2170-5.

  5. Denis F. Spinal instability as defined by the three-column spine concept in acute spinal trauma. Clin Orthop. 1984; 189: 65-76.

  6. Gertzbein S.D. Scoliosis research society multicenter spine fracture study. Spine 1992; 17:528-40.

  7. Kraemer W.J., Schemitsch E.H., Lever J., McBroom R.J., McKee M.D., Waddell J.P. Functional outcome of thoracolumbar burst fractures without neurological deficit. J Orthop Trauma. 1996;541-4.

  8. Mumford J., Weinstein J.N., Spratt K.F., Goel V.K. Thoracolumbar burst fractures. The clinical efficacy and outcome of nonoperative management. Spine 1993; 18: 955-70.

  9. Shen W.J., Liu T.J., Shen Y.S. Nonoperative treatment versus posterior fixation for thoracolumbar junction burst fractures without neurologic deficit. Spine. 2001;26:1038-45.

  10. Wood K., Butterman G., Mehbod A., Garvey T., Jhanjee R., Sechriest V. Operative compared with nonoperative treatment of a thoracolumbar burst fracture without neurological deficit. A prospective, randomized study. J Bone Joint Surg 2003; 85-A:773-81.

  11. White A.A., Panjabi M.M. Clinical Biomechanics of the Spine. 2nd ed. Philadelphia: JB Lippincott, 1990.

 

 
 
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