Spontaneous regression of curve in immature idiopathic scoliosis - does spinal column play a role to balance? An observation with literature review

Abstract

BackgroundChild with mild scoliosis is always a subject of interest for most orthopaedic surgeons regarding progression. Literature described Hueter-Volkmann theory regarding disc and vertebral wedging, and muscular imbalance for the progression of adolescent idiopathic scoliosis. However, many authors reported spontaneous resolution of curves also without any reason for that and the rate of resolution reported is almost 25%. Purpose of this study was to question the role of paraspinal muscle tuning/balancing mechanism, especially in patients with idiopathic scoliosis with early mild curve, for spontaneous regression or progression as well as changing pattern of curves.MethodsAn observational study of serial radiograms in 169 idiopathic scoliosis children (with minimum follow-up one year) was carried. All children with Cobb angle < 25° and who were diagnosed for the first time were selected. As a sign of immaturity at the time of diagnosis, all children had Risser sign 0. No treatment was given to entire study group. Children were divided in three groups at final follow-up: Group A, B and C as children with regression, no change and progression of their curves, respectively. Additionally changes in the pattern of curve were also noted.ResultsAverage age was 9.2 years at first visit and 10.11 years at final follow-up with an average follow-up of 21 months. 32.5% (55/169), 41.4% (70/169) and 26% (44/169) children exhibited regression, no change and progression in their curves, respectively. 46.1% of children (78/169) showed changing pattern of their curves during the follow-up visits before it settled down to final curve. Comparing final fate of curve with side of curve and number of curves it did not show any relationship (p > 0.05) in our study population.ConclusionPossible reason for changing patterns could be better explained by the tuning/balancing mechanism of spinal column that makes an effort to balance the spine and result into spontaneous regression or prevent further progression of curve. If this which we called as "tuning/balancing mechanism" fails, curve will ultimately progress.

Evolution of the curve patterns during brace treatment for adolescent idiopathic scoliosis

“…In addition, the aggravation of the secondary curve may also contribute to the curve pattern changes, such as from single thoracic to double major curve. Many authors assume that as scoliosis is developing, the vertebral column tries to rebuild a new balance [12,[32][33][34]. Thus, in thoracic AIS, a lumbar curve develops to compensate for the deviation of the thoracic vertebrae to reconstruct the balance of the trunk.…”

The role of the paravertebral muscles in adolescent idiopathic scoliosis evaluated by temporary paralysis

“…Today, the etiology of AIS is still considered multifactorial, even though over time many researchers have tried to explain the pathology by one single etiology, ranging from a broad variety of causes of either biomechanical or genetic nature [ 2 – 6 ]. One relative recent observation by Modi et al is that the spinal deformity in mild AIS tries to return to the neutral midline position, thereby displaying a “wavy” curve pattern with fluctuations in a lateral curve shape when followed closely [ 4 ]. They suggested that the paravertebral muscles would have a “tuning/balancing mechanism” that tries to correct the spinal deformity of mild scoliosis into apparent spontaneous regression or to prevent further progression of curve, and if failing, this would result in further progression [ 4 ].…”

“…One relative recent observation by Modi et al is that the spinal deformity in mild AIS tries to return to the neutral midline position, thereby displaying a “wavy” curve pattern with fluctuations in a lateral curve shape when followed closely [ 4 ]. They suggested that the paravertebral muscles would have a “tuning/balancing mechanism” that tries to correct the spinal deformity of mild scoliosis into apparent spontaneous regression or to prevent further progression of curve, and if failing, this would result in further progression [ 4 ]. The natural history of AIS, where the majority spontaneously remains stable while the rest either regresses or progresses, may be seen as suggestive for this hypothesis [ 7 ], and the paravertebral muscles or rather a misbalance of the paravertebral muscles has been suggested as causative for progression or regression of AIS [ 3 , 4 , 6 , 8 , 9 ].…”

TIMP2 Polymorphisms Association With Curve Initiation and Progression of Thoracic Idiopathic Scoliosis in the Caucasian Females

“…AIS is a tridimensional spine deformity with a lateral curvature greater than 10 degrees with vertebrae rotation and sagittal plane imbalance . Progression of the deformity occurs in 10–15% of cases and is most common in females during pubertal growth …”

“…[3][4][5] Progression of the deformity occurs in 10-15% of cases and is most common in females during pubertal growth. 1,[6][7][8][9][10][11] Although wide research is conducted in the field, etiopathogenesis of IS remains poorly understood. 9,12 Genetic factors have been reported to contribute significantly to idiopathic scoliosis etiology.…”