July 2017

Scoliosis bracing: Potential effects on gait and balance

By Barbara Boughton

Idiopathic scoliosis, most common in adolescent girls, is marked by a single or double spinal curve, hip and shoulder asymmetry, and pelvic obliquity (or limb-length discrepancy). These structural issues can be associated with biomechanical issues that include postural instability, decreased proprioception, altered lumbopelvic muscle activation patterns, and gait asymmetry.1-4

These gait, posture, and balance problems often arise from muscle imbalances, spinal rigidity, and tightness in the body’s bony structure, as well as compensation mechanisms for these deficits, according to Sun Hae Jang, MSc, CO, FAAOP, an assistant professor in the orthotics and prosthetics master’s degree program at Eastern Michigan University in Ypsilanti.

Pelvic obliquity plays a role in the postural imbalance seen in scoliosis patients too. It is a significant contributor to gait deviations, according to Keith Smith, CO, of O&P Orthotic and Prosthetic Lab in St. Louis, MO.

Studies have clearly shown bracing has a significant benefit for adolescents with idiopathic scoliosis. The largest prospective trial of bracing in idiopathic scoliosis5 found 75% of patients who wore braces at least 18 hours a day did not progress to high-risk curves of 50° or more—the threshold for surgical treatment. The study of 242 patients, which was published in 2013 by the New England Journal of Medicine (NEJM), demonstrated such a clear benefit for bracing in high-risk patients that it was discontinued early so patients in the control group could receive brace treatment.

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Mixed messages

Some studies support clinicians’ observations that bracing can be helpful for gait, posture, and balance issues in scoliosis patients. Other studies, however, have found bracing had no effect, or a negative effect, on these symptoms.

“Certainly, corrective orthoses should bring the imbalanced spine to the neutral position. And a balanced spine will eventually provide postural stability during gait,” Jang said.

Bracing can also positively affect gait by improving walking speed and cadence, added Mokhtar Arazpour, PhD, a researcher in the department of orthotics and prosthetics at the University of Social Welfare and Rehabilitation Sciences in Tehran, Iran.

“Bracing also decreases gait load asymmetry, improves hip and pelvic movement symmetry, and decreases pelvic and hip frontal plane motion,” Arazpour said.

Brace-related improvements in gait and balance have the potential to improve compliance with bracing as well as overall physical activity, which research suggests is significantly lower in patients with scoliosis than in their unaffected peers.6,7 Although the reasons for limited physical activity in scoliosis patients are unclear, researchers have suggested that altered gait—and subsequent effects on energy cost—may play a role.6

Recent gait analysis studies have begun to shed more light on the causes of gait and balance problems in scoliosis patients, and the ways in which bracing can help alleviate or exacerbate these issues.

Scoliosis and gait

In one such study, researchers found untreated scoliosis patients showed slight but significant modifications in gait, even in cases of mild scoliosis.8 Although these slight modifications in gait are often not apparent to the naked eye, gait analysis technology revealed less pelvic frontal plane motion (mediolateral tilting) than in unaffected individuals, as well as less hip and shoulder motion.8

Another study on gait initiation9 found lateral steps in scoliosis patients were accompanied by increases in ground reaction forces and impulses compared with age-matched healthy controls. Scoliosis patients also had slower dynamic behavior and were less symmetrical than controls.9

A team of researchers from Belgium and Canada also quantified the internal joint efforts or forces during gait in scoliosis patients to better understand the pathophysiology and progression of the disease. In the study, published in 2015 in Scoliosis,10 the researchers studied 12 healthy individuals and 12 patients with idiopathic scoliosis while they walked on a treadmill. Mediolateral forces at the right hip were significantly lower in the scoliosis patients than in healthy individuals, which the researchers concluded could gradually cause postural adjustments in the scoliosis patients during gait.

“Even with a small disequilibrium, there are often huge efforts by the human body to compensate, and internal postural adjustments,” said Maxime Raison, PhD, one of the study’s authors, who is a professor at the Polytechnique Montreal and researcher at Sainte-Justine University Hospital Center in Montreal, Canada. “This can create gait difficulties.”

At the same time, he added, it’s not clear if spinal orthoses satisfactorily address the gait problems associated with scoliosis, or if they have an overall positive effect on gait.

In a 2014 study,3 for instance, French and Canadian researchers assessed the long-term effects of brace wear, worn for 22 hours a day over six months, by 13 adolescents with idiopathic scoliosis. After six months, the main structural thoracolumbar/lumbar curve was partly corrected in the scoliosis patients, and frontal and hip motion increased, helping to improve muscular mechanical work. Yet the electromyographic (EMG) activity duration of the lumbo­pelvic muscles did not change relative to baseline, except in the erector spinae, where EMG activity decreased.

Although brace treatment was not associated with negative effects on gait in the scoliosis patients, it also did not appear to help reduce the excessive energy cost of walking, which remained 30% above that of healthy age-matched controls.

Photo courtesy of scoliosisjourney.wordpress.com

Scoliosis and balance

Some experts have hypothesized that, because braces constrain movement, they could negatively affect balance control.4 But studies on scoliosis bracing and postural control have also had mixed results.

In a 2015 study, researchers assessed postural control in 13 pediatric patients with idiopathic scoliosis in braced and unbraced conditions.4 Compared with the no-device condition, brace wear was associated with lower equilibrium scores while standing with eyes closed and higher equilibrium scores when holding on to a swaying support with eyes closed. The patients also had higher composite equilibrium scores on sensory organization tests, slower reaction time on limits of stability tests, and higher movement velocity with a brace than without. Despite some limitations in balance while patients were braced, the researchers concluded the spinal brace improved postural stability in terms of increased proprioception, equilibrium performance, and rhythmic movement ability.

However, another study by Iranian researchers published in 2014 found that eight girls with scoliosis, who wore a brace for four months, had less sway with the orthosis than without, with the eyes both open and closed while standing on a solid surface.11 Bracing was also associated with less sway when standing on the dominant leg on a solid surface with eyes both open and closed, but their sway did not improve when standing on the dominant leg on a foam surface with eyes closed.11

In a follow-up study published in 2016, the same researchers discovered that eight girls with idiopathic scoliosis had weaker balance than eight healthy girls after one and four months of brace wear.12 The center of pressure and center of gravity sway in the scoliosis patients was increased compared with baseline for the majority of the tests at one and four months, but there were no significant differences in any of the test conditions when the scoliosis subjects were braced or unbraced.12

Arazpour, a coauthor of both studies, noted that while bracing did not improve balance in scoliosis patients compared with controls in the follow-up study, the earlier research had found that wearing a brace can improve quiet standing balance in scoliosis patients over time. Due to the different conclusions of these and other studies, the question of whether braces help scoliosis patients achieve better balance needs to be further investigated in longer-term investigations, he said. He also noted his studies used only laboratory tests of balance, and clinical tests may create different results.

“We also suggest that patients should be followed more closely and prescribed therapeutic exercises to improve balance,” Arazpour said.

Anecdotal optimism

Despite the mixed results of these studies, clinicians interviewed by LER said they have found that braces improve posture and have no negative effects on gait. Jang noted that braces balance the spine, which eventually provides postural stability. However, she added, poorly made orthoses—those that don’t provide adequate sagittal-plane correction—can exacerbate the balance problems associated with scoliosis.

Thomas Gavin, LCO, AFSRS, an orthotic consultant in Palos Park, IL, noted patients can often experience increased imbalance and gait-related issues in the first few weeks of brace wear. However, these problems tend to even out and resolve on their own within six weeks, Gavin said.

“The braces retrain the sensory integration patients in scoliosis patients,” he said.

Gavin also noted the bracing outcomes can depend on how often patients are followed and come in for adjustments. He has worked with different research and medical groups that had different rates of surgery—in cases of incomplete brace correction—among patients with scoliosis who initially were managed orthotically.

In the NEJM study on scoliosis and bracing, for instance, patients were followed carefully at six-month intervals, and braces were kept accurately adjusted.5 As a result, the percent of patients who progressed to the point of needing corrective surgery was just 25%. Previous studies, however, have reported rates of post-bracing curve progression warranting surgery that ranged from 0% to 79%,13-15 and the NEJM study authors wrote that they had expected the rate in their braced cohort to be closer to 15%.5

Although the triplanar shift in center of gravity associated with bracing can affect balance and gait, Smith said in his experience that hasn’t been a major clinical challenge.

“I have never come across a patient for whom the difference was problematic, and one-hundred percent have adapted within two weeks to the orthosis with regard to balance and gait,” Smith said. “Most patients say that they eventually recognize that they feel out of balance when the brace is taken off [for short periods during the course of treatment] compared to being worn.”

Barbara Boughton is a freelance writer based in the San Francisco Bay Area.

REFERENCES
  1. Kramers-de Quervain IA, Müller R, Stacoff A, et al. Gait analysis in patients with idiopathic scoliosis. Eur Spine J 2004;13(5):449-456.
  2. Yang JH, Suh SW, Sung PS, Park WH. Asymmetrical gait in adolescents with idiopathic scoliosis. Eur Spine J 2013;22(11):2407-2413.
  3. Mahaudens P, Raison M, Banse X, et al. Effect of long-term orthotic treatment on gait biomechanics in adolescent idiopathic scoliosis. Spine J 2014;14(8):1510-1519.
  4. Gur G, Dilek B, Ayhan C, et al. Effect of a spinal brace on postural control in different sensory conditions in adolescent idiopathic scoliosis: A preliminary analysis. Gait Posture 2015;41(1):93-99.
  5. Weinstein SL, Dolan LA, Wright JG, Dobbs MB. Effects of bracing in adolescents with idiopathic scoliosis. N Engl J Med 2013;369(16):1512-1521.
  6. Muller C, Fuchs K, Winter C, et al. Prospective evaluation of physical activity in patients with idiopathic scoliosis or kyphosis receiving brace treatment. Eur Spine J 2011;20(7):1127-1136.
  7. Uhlenbrock K, Thorwesten L, Sandhaus M, et al. Physical education and daily life activity of nine and eleven year old pupils. Dtsch Z Sportmed 2008;59:228-233.
  8. Mahaudens, Banse X, Mousny M, et al. Gait in adolescent idiopathic scoliosis: Kinematics and electromyographic analysis. Eur Spine J 2009;18(4):512-521.
  9. Bruyneel AV, Chavet P, Bollini G, et al. Lateral steps reveal adaptive biomechanical strategies in adolescent idiopathic scoliosis. Ann Readapt Med Phys 2008;51(8):630-641.
  10. Yazji M, Raison M, Aubin CE, et al. Are the mediolateral joint forces in the lower limbs different between scoliotic and healthy subjects during gait? Scoliosis 2015;10(Suppl 2):S3.
  11. Khanal M, Arazpour M, Hutchins SW, et al. The influence of thoracolumbosacral orthoses on standing balance in patients with adolescent idiopathic scoliosis: a pilot study. Disabil Rehabil Assist Technol 2014 Apr 9. [Epub ahead of print]
  12. Khanal M, Arazpour M, Bahramizadeh M, et al. The influence of thermoplastic thoraco lumbo sacral orthoses on standing balance in subjects with idiopathic scoliosis. Prosthet Orthot Int 2016;40(4):460-466.
  13. Dolan LA, Weinstein SL. Surgical rates after observation and bracing for adolescent idiopathic scoliosis: an evidence-based review. Spine 2007;32(Suppl 1):S91-S100.
  14. Danielsson AJ, Hasserius R, Ohlin A, Nachemson AL. A prospective study of brace treatment versus observation alone in adolescent idiopathic scoliosis: a follow-up mean of 16 years after maturity. Spine 2007;32(20):2198-2207.
  15. Janicki JA, Poe-Kochert C, Armstrong DG, Thompson GH. A comparison of the thoracolumbosacral orthoses and Providence orthosis in the treatment of adolescent idiopathic scoliosis: results using the new SRS inclusion and assessment criteria for bracing studies. J Pediatr Orthop 2007;27(4):369-374.
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