Orthotic Treatment for Pathological Fractures to the Osteoporotic Spine.

ORTHOTIC TREATMENT FOR TRAUMATIC SPINAL FRACTURES

Thomas M. Gavin, C.O.

ORTHOTICS

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(630) 986-0007

- INTRODUCTION

- TREATMENT ALTERNATIVES

- ORTHOTIC STABILIZATION

- BIOMECHANICS

- CLINICAL STUDIES

- MECHANISM OF TREATMENT

- SUGGESTED REFERENCES
 

Traumatic injuries to the thoracic and lumbar spine are a result of motor vehicle accidents, falls, acts of violence, recreational sports activities, and other causes. Injury statistics show the thoracolumbar region to be the most susceptible to injury (Kazarian, 1975). Clinical data from other investigators also support this observation (Denis, 1983; McEvoy and Bradford, 1985; Weinstein, et al. 1988). 

Many traumatic spinal injuries do not cause paralysis yet leave a marginally stable or an unstable spinal segment as a result of disruption of bony elements and soft tissues. The residual instability causes a deformity called a gibbus and if left untreated may progress, thus causing late paralysis.

The various anatomical components of a spinal segment provide inherent stability to the spinal segment. Traditionally, these elements have been grouped into two load-bearing columns, anterior (front) and posterior (back). The anterior column consisted of elements anterior to and including the posterior longitudinal ligament, while the posterior column consisted of the posterior ligamentous complex. The stability of a segment defined by its load-displacement behavior is affected by an injury and the extent of such effect is a function of the type of injury, i.e., the anatomical components disrupted by the injury and the severity of the damage. 

To classify acute thoracolumbar fractures, Denis (1983) proposed that the spine has three load-bearing columns on the sagittal plane (side view). The anterior (front) column is formed by the anterior longitudinal ligament, anterior annulus fibrosis (disc), and anterior part of the vertebral body. The middle column is formed by the posterior longitudinal ligament, posterior annulus fibrosis (disc) and posterior wall of the vertebral body. The posterior (back) column is formed by the posterior vertebral arch, supraspinous ligament, interspinous ligament, capsule, and ligamentum flavum. 

Compression fractures involve failure (bony disruption) of the anterior column with the middle column being totally intact. Burst fractures involve failure (bony and some soft tissue disruption) of both the anterior and middle columns. The seat-belt-type injuries represent failure (bony and/or soft tissue disruption) of the middle and posterior columns. Finally, the fracture dislocation injury represents failure (bony and soft tissue) of all three columns. 

TREATMENT ALTERNATIVES

Failure of the column/columns leads to a translational and angular deformity known as a gibbus which may or may not have a tendency to progress. Progression refers to the increasing of the angle of the affected spinal segment and relative increasing the posterior translation of the injured segment caused from the injured segment's inability to bear the weight of the body above the injury. This tendency to progress is known as instability. Since the nature of injury and any related instability is mechanical, treatment generally requires mechanical stabilization or an augmentation of the injured sites ability to bear weight without progressing the deformity at the injured site. Mild injuries such as some single column compression fracture usually don't require any stability augmentation and is frequently treated with 48 hours bedrest and a lumbosacral corset for pain control. Moderate injuries such as more severe compression fractures, multi level compression fractures as well as moderate burst and Chance fractures (two column bony injuries) require stability augmentation by either a brace or sometimes requires surgical reduction with fixation by an implant and spinal fusion. Severe injuries such as the three column fracture dislocation, severe and multi level burst fractures are usually so unstable that a brace will not provide enough stability. These injuries usually require surgery to stabilize the unstable segment or segments. Slice fractures (posterior and middle column disruptions through soft tissue) require surgical stabilization. Whereas a brace may stabilize a slice fracture, the soft tissue will not heal so the instability will still be apparent once the brace is removed. 

ORTHOTIC STABILIZATION

Spinal orthoses have a long and vast tradition of usage for treating spinal conditions. The first evidence of spinal orthoses may be traced to Galen (131 A.D. to 201 A.D.). Orthoses were originally constructed of materials such as whale bone and tree bark. Crude lumbar supports fashioned from tree bark were recovered by Archaeologists from the cliff dwellings of the pre-Columbian Indians and were not unlike many of the thermoplastic spinal braces used today. During the Eighteenth and Nineteenth centuries the Europeans used several orthoses designed in a variety of different fashions and fabricated from combinations of leather, steel and plaster of Paris. The most recent developments occurred in the 1960s and 1970s and replaced the former steel and leather designs with aluminum and various thermoplastics. Regardless of the materials used to construct spinal orthoses, the indications for and usage of spinal orthoses is unchanged. Orthoses for spinal injury are designed to protect the spinal column from loads and stresses that cause progression of the angular and translational deformity from the injury. 

Current usage of spinal orthoses for thoracolumbar injuries depend on the amount of support or stabilization required and vary with injury. Mild injuries are at low risk of progression of injury and require minimally immobilizing orthoses only while the more severe injuries that have marginal stability yet do not require surgery, need orthoses that offer maximum stabilization and resistance to further progression of the deformity. 

BIOMECHANICS

Orthoses primarily function to augment biomechanical stability of a disrupted vertebral segment or segments. The most minimal of these functions is that of a limiter of gross trunk motion. Gross trunk motion is the movement and sway of the vertebral column during activities of normal daily living. Orthoses that primarily restrict gross trunk motion do not necessarily limit segmental motion but will minimally augment stability to the vertebral column by reducing overall bending moments on the lower spine by restricting bending and slouching. The next mechanism of orthotic stabilization is the reduction of inter-segmental motion. Inter-segmental motion is the motion that one vertebra exhibits that is relative to the vertebra that is just above and the vertebra just below. Orthoses that reduce segmental motion may be assumed to also reduce overall gross spinal motion. The third mechanism is that of `three-point' sagittal (side view) hyperextension. Biomechanical studies have defined the ability of various orthoses to limit overall gross and segmental motion of the spine. 

Stable thoracolumbar fractures without signs of neurologic compromise are usually treated nonoperatively with an orthosis that provides maximum sagittal hyperextension, while surgery is indicated in those fractures that are considered highly unstable. However, there appears to be considerable controversy in deciding which fractures have enough stability to be treated in an orthosis only and which need surgical stabilization. 

CLINICAL STUDIES

Weinstein (1988) reported 42 cases of traumatic burst fractures of the thoracolumbar spine treated nonoperatively in a body cast, brace or bed rest. Burst fractures of the thoracolumbar spine without neurologic deficit treated conservatively had acceptable long-term results in most cases. Chance (1948) reported on lap belt fractures through osseous tissue, and found good results after treatment in hyperextension. Gertzbein (1987) recommended that patients with flexion distraction injuries (Chance fractures) of the thoracolumbar spine involving only bony injuries be treated nonoperatively in a hyperextension brace. McEvoy and Bradford (1985) reported on nonoperative treatment of burst fractures of the thoracic and lumbar spine and showed good results. Patients wore a cast or polypropelene brace for an average of 4.5 months (range, 2-6 months). These were removed at the discretion of the treating physician, and radiographs were obtained to assess stability and healing. Willen et al (1985) in one study and Davies et al (1980) in another, also reported on the usage of a hyperextension brace in the nonoperative treatment of fractures in the thoracolumbar region and found the non surgical approach to be as effective as surgery. White and Panjabi (1988) suggest reduction in a hyperextension cast for treatment of moderate to severe wedge compression fractures. These clinical studies of nonoperative treatment of thoracolumbar injuries are supported by the analytical work of Patwardhan et al (1990). The majority of single and two column Thoracolumbar spinal fractures without neurolgic deficit can be treated in a brace with good result. The brace must be fabricated and fitted properly thus providing measurable hyperextension and immobilize the spine three-dimensionally.

MECHANISM OF ORTHOTIC TREATMENT
 

Figure 1A: The Lumbosacral corset. Due to the short height and the use of canvas in the construction, this orthosis will do little more than reduce gross trunk motion.

White and Panjabi (1990) reported that single column compression fractures with loss of one-third or less anterior height can be treated with active exercise and mobilization after a period of bed rest to allow acute symptoms to subside and to permit any slow elastic recoil. These fractures are usually stable and do not require an orthosis to improve stability, however a lumbosacral corset (Figure 1A) may be worn to reduce gross trunk motion for pain management. For nonoperative management of the more severe compression fracture, an orthosis must not only reduce gross trunk motion but also must reduce segmental motion at the injured segment and provide sagittal plane hyperextension. The Jewett hyperextension orthosis (Figure 1B) has long been the standard orthosis for this treatment although in recent years the Cash orthosis (Figure 1C) has been an acceptable alternative. Whereas the Jewett and Cash orthosis function well on the sagittal plane, they both lack the ability to decrease motion on the coronal and transverse planes. To treat the severe compression fracture that is at the uppermost limit of nonoperative treatment, the orthosis must provide sagittal three point hyperextension, as well as reduce gross trunk and segmental motion on all three planes. This is best accomplished with a custom molded TLSO, fitted in hyperextension (Figure 1D). For nonoperative stabilization of compression fractures the optimal orthosis will provide measurable extension at the injured segment on the lateral radiograph as shown in Figures 2A&B. Patient restriction is suggested to be orthosis wear during waking hours, minimal lifting, no running and no sports while the injury restores itself to normal strength.
 

Figure 1B: The Jewett hyperextension orthosis. This orthosis proves excellent three point loads on the sagittal plane but does very little in motion reduction in the coronal and transverse planes.	Figure 1C: The Cash hyperextension orthosis. This orthosis is similar to the Jewett in that it provides excellent sagittal hyperextension and does not immobilize the coronal and transverse planes. Unlike the Jewett, the Cash is light weight and more cosmetic.	Figure 1D: The custom molded TLSO. Note that the sagittal appearance of the TLSO shown here suggests that this TLSO is in hyperextension. This orthosis is also excellent in sagittal plane hyperextension but will also reduce coronal and transverse plane motion. This orthosis for an average adult usually weighs between three and four pounds.

Two column injuries such as the burst fracture has been shown to have acceptable results in most cases when treated in orthoses. Once again the ideal orthosis for the burst fracture must provide measurable segmental extension on the lateral radiograph (Figure 2C&D). For the mild burst fracture a lumbosacral corset will not provide enough stability. The Jewett or Cash orthosis may be adequate but patient restrictions must be increased. Lifting must be eliminated since the two column injury is more susceptible to progression under normal physiologic loads and stability of the spinal column in the orthosis is greatly decreased during large flexion moments that occur during lifting. For the moderate burst fracture the custom molded TLSO must be used as it will provide multiplanar stabilization as well as hyperextension. Since the TLSO is individually designed to patient anatomic and injury specifications, fabrication and donning methods may be utilized to enhance stability and patient restriction. First and foremost the burst fracture usually presents with a greater gibbus deformity. For ease of extension of the gibbus the TLSO should be donned and tightened while the patient is supine. This will eliminate the axial load of the head and torso (weight bearing on the injured segment) on the gibbus during donning and enable a snug fit. This is an important basic concept in providing resistance to the deformity because if the orthosis is donned loosely the effect will be a loss of stability and an increase in the gibbus. Also the superior trimline on the anterior shell may be lengthened in height to the delto-pectoral (shoulder front) groove which will lessen the distance of the upperlimb reach away from the torso thus lessening the flexion moments applied to the spine cephalad to the injury. Running, sports and prolonged sitting is some of the patient restrictions besides lifting that will insure minimal stresses on the injury. 
 

Figure 2A&B: Pre orthosis and in orthosis radiographs of the single anterior column compression fracture, depicting segmental extension yielded by a TLSO.

Figure 2C&D: Pre orthosis and in orthosis radiographs of the anterior and middle, two column burst fracture, also depicting segmental extension yielded by a TLSO.

Posterior and middle column injury through osseous tissue has also been cited to have excellent results when treated nonoperatively in hyperextension. Three point sagittal hyperextension is also the primary role of an orthosis for these injuries. Since these injuries also effect two columns, the custom molded TLSO is the optimum orthosis for treatment. These lap belt type injuries should also demonstrate measurable extension of the injured segments on the lateral radiograph. Figures 3A- D Depict a lap belt injury in a 9 year female who was gradually extended in a TLSO in hyperextension during the first few weeks post injury and a follow-up radiograph four months later showing maintenance of the segmental extension. This patient also demonstrated a significant cosmetic improvement of the deformity. Since these injuries are through osseous tissue, the segmental extension closes the fracture in the posterior column thus allowing ossification. This method of treatment will only yield an excellent result if the orthosis is capable of segmental extension. The same restrictions apply to these patients as discussed for the moderate burst fracture. 

Figure 3A: PreTLSO and in TLSO radiographs of the posterior and middle, two column Chance fracture.	Figure 3B: shows only minimal extension at the injured segment and a second TLSO in greater hyperextension was prepared because of this.	Figure 3C: depicts a much better result.	Figure 3D: After nearly five months in a TLSO this Chance fracture has maintained good extension.

The posterior and middle column injury through soft tissue commonly known as the slice fracture should not be treated nonoperatively. Whereas an orthosis is capable of increasing the stability and extending the injured segments, this injury will not heal. Slice fractures require surgical reduction and fusion. Likewise, severe two column injuries as well as three column injuries such as the fracture-dislocation cannot be treated nonoperatively with good result. The resultant instability of the injury is so great that an orthosis cannot provide enough stability to prevent progression of the deformity. Figure 4A shows a lateral radiograph of an adult male with a fracture dislocation who is neurologically intact and unfortunately was treated with an orthosis only. Figure 4B shows a progression of the deformity in the orthosis several weeks later and this resulted in complete paraplegia. These radiographs support the work of Patwardhan et al (1990) that utilized a finite element model showing that the deformity of a three column injury will progress in a three point hyperextension orthosis. 

Figure 4A&B. These radiographs depict out of orthosis and in orthosis three column fracture dislocation. This fracture was beyond the threshold of nonoperative treatment and the orthosis was unable to stabilize it. The result was complete paraplegia while in the orthosis.

When using an orthosis for nonoperative treatment of spinal injury the criteria for orthosis selection should be based on biomechanical deficit and the vulnerability of deformity progression. If at anytime during the nonoperative treatment the deformity shows progression, the decision to proceed with this modality should be reevaluated so the patient is not put at risk of neurologic deficit. The most ideal orthosis will not function well if it is not worn properly or at all. Patient compliance is essential for the success of this treatment. 

Proper decision making for the selection of a spinal orthosis for thoracolumbar injury treatment is a combination of sound biomechanical mechanism of action, clinical intuition and patient subjectivity. Over treating or under treating an injury with an orthosis can lead to detrimental results. Following established criteria for selection of an orthosis and informing the patient as to the consequences of non compliance will more frequently than not yield the best result. If there is any question of spinal injury, consult your physician immediately. 

SUGGESTED REFERENCES

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2. Bunch WH, Keagy R: Principles of Orthotic Treatment, C.V. Mosby co. St. Louis, Missouri, pps. 1-5, 1975 

3. Chance GQ : Note on a type of flexion fracture of the spine. Br. J. Radiol., 21: 452, 1948 

4. Davies WE, Morris JH, and Hill V,: An analysis of conservative (nonsurgical) management of thoracolumbar fractures and fracture dislocations with neural damage. J. Bone Jt. Surg., 62A: 324, 1980 

5. Dorsky S, Buchalter D, Kahanovitz N, Nordin M: A three dimensional analysis of lumbar brace immobilization utilizing a noninvasive technique. Proceedings of the 33rd Annual Meeting, Orthopaedic Research Society, San Francisco, California, 1987 

6. Fidler MW, Plasmans CMT: The effect of four types of support on the segmental mobility of the lumbosacral Spine. J Bone Jt Surg 65A:943-947, 1983 

7. Gertzbein SD, Court-Brown CM: The rationale for management of flexion/distraction injuries of the thoracolumbar spine based on a new classification. Proceedings of the 22nd Annual Meeting of the Scoliosis Research Society, Vancouver, B.C., Canada, September 1987. 

8. Gilbertson LG, Goel VK, Patwardhan AG, Havey R, Morris T, Gavin TM: The biomechanical function of `three point' hyperextension orthoses. Proceedings of the American Society of Mechanical Engineers 112th winter annual meeting, Atlanta, Georgia, December 1991 

9. Krag MH, Byrne KB, Pope MH, Bayliss D: The effect of back braces on the relationship between intra-abdominal pressure and spinal loads. Advances in Bioengineering pp. 22-23, 1986 

10. Lantz SA, Schultz AB: Lumbar spine orthosis wearing- I. Restriction of gross body motions. Spine 11(8): 834-837, 1986a 

11. Lantz SA, Schultz AB: Lumbar spine orthosis wearing- II. Effect on trunk muscle myoelectric activity. Spine 11(8):838-842, 1986b 

12. Lonstein JE: History of spinal bracing. Orthotics 703, course for physicians and surgeons, Northwestern University Medical School, Prosthetic-Orthotic Center. 1989-1992 

13. Lorenz MA, Patwardhan AG, Zindrick MR: Instability and mechanics of implants and braces for thoracic and lumbar fractures. in Spinal Trauma, T Errico, Ed., J.B. Lippincott and Co., pp. 271-280, 1990 

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15. McEvoy RD, Bradford DS: The management of burst fractures of the thoracic and lumbar spine- Experience in 53 patients. Spine 10(7): 631-637, 1985 

16. Morris JM, Lucas DB: Physiological considerations in bracing of the spine. Orthop Prosth Appl 37: 44, 1963 

17. Nachemson A, Elfstrom G: Intravital wireless telemetry of axial forces in Harrington distraction rods in patients with idiopathic scoliosis. J Bone Jt Surg 53A:445-465, 1971 

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19. Nachemson A, Schultz A.B, Andersson GBJ: Mechanical effectiveness studies of lumbar spine orthoses. Scand J Rehab Med Suppl 9, 1983 

20. Nagel DA, Koogle TA, Piziali RL, Perkash I: Stability of the upper lumbar spine following progressive disruptions and the application of individual internal and external fixation devices. J Bone Jt Surg 63A: 62-70, 1981

21. Norton PL, Brown T: The immobilizing efficiency of the back braces; their effect on the posture and motion of the lumbosacral spine. J Bone Jt Surg 39A:111-139, 1957 

22. Patwardhan AG, Li S, Gavin TM et al: Orthotic stabilization of thoracolumbar injuries- A biomechanical analysis of the Jewett hyperextension orthosis. Spine 15(7): 654- 661, 1990 

23. Waters RL, Morris JM: Effects of spinal supports on the electrical activity of muscles of the trunk. J Bone Jt Surg 52A: 51-60, 1970 

24. Weinstein JN, Collalto P, Lehmann TR: Thoracolumbar "burst" fractures treated conservatively: A long-term follow-up. Spine 13(1):33-38, 1988 

25. White A, Panjabi M: Clinical Biomechanics of the Spine. second edition, J. B. Lippincott and co., pps. 235-255, 1990 

26. Willen J, Lindahl S, Nordwall A: Unstable thoracolumbar fractures- A comparative clinical study of conservative treatment and Harrington instrumentation. Spine 10(2):111-122, 1985

Updated  01-2001