Background

Scoliosis is a major demographic health issue in the adult population with pain, imbalance and curve angular progression. The natural evolution of late onset scoliosis has been well described with annual progression of 1° for curves of more than 50° [1, 2]. Surgeons are often very conservative in the treatment of adult scoliosis because of the complication rates higher than for adolescent and the marginal bone quality endemic to this population. There is currently a lack of literature for adult scoliosis rigid bracing. Rare publications present the short term results on pain and some examples of rigid bracing [3–5].

A 5-year minimum follow up can help to quantify the effect of the brace on the angular progression and other clinical parameters of adult scoliosis like bib hump, frontal and sagittal balance.

Methods

The Lyon Conservative treatment requires:

  1. 1.

    A plaster cast made in a specific standing frame for 3 weeks.

  2. 2.

    A rigid polyethylene bivalve overlapped brace worn for at least 4 h per day.

  3. 3.

    A specific physiotherapy to prevent muscle atrophy.

The plaster cast or full time bracing is an indispensable prerequisite for this treatment. Besides the therapeutic role of muscular-ligamentous adjustment of paravertebral tension (creep), it can also be used as a test. The patient must be pain-free while pursuing normal activities [6].

The principle of bracing is completely different from that of adolescent scoliosis. Indeed, the aim is to:

  1. 1.

    Decompress the discs with the “hourglass effect” lifting the trunk under the fluctuating ribs and transfer the pressure on the iliac crest.

  2. 2.

    Rebalance the spine in both frontal plane and sagittal plane, mostly by recreating lumbar lordosis.

  3. 3.

    Relieve pain by the analgesic effect of rigid low back brace.

The protocol is full time 24 h a day during 3 weeks, and at least four hours per day for a minimum of 6 months (Fig. 1).

Fig. 1
figure 1

Some samples of polyethylene bivalve overlapping braces. The anterior thrust can be xyphoidal under the breast or sternoclavicular. It is performed after correcting plaster cast

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Results

Group definition

From 1998 to 2013, rigid bracing with plaster cast for adult scoliosis was proposed in 739 cases (group A). 661/739 = 83 % patients: have accepted the treatment. 158/739 = 21 % were reviewed at least 5 years after the start of treatment (group B) (Additional file 1 – Excel spreadsheet with results of 158 patients).

SPSS 20 pack with a Confidence interval of 95 % is used (Table 1).

Table 1 Comparison of 8-year follow-up group with all patients
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There is no statistical difference in age between the two groups, but the initial angulation is significantly 4 ° higher.

Female/Male ratio is 91 %. The average follow-up is 8.41 years ± 3.26 (from 5 to 17 years).

Descriptive statistics

Four parameters are studied: 1. Cobb angulation, 2. frontal balance with C7 plumb line, 3. sagittal balance with C7 plumb line, 4. Rib hump measured in mm (Table 2).

Table 2 Comparing means at the beginning and at the last control with T-Test
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The Cobb angle has been stabilized by bracing. The average is the same when it should be greater by 4° (0.5 ° × 8 years) if we take into account the spontaneous natural evolution of scoliosis in adulthood.

Taking into account the SRS criteria to express the results, we get the following results:

  1. 1.

    Stable: 88/158 = 56 %

  2. 2.

    Improvement of more than 5 °: 38/158 = 24 %

  3. 3.

    Worsening of more than 5 °: 32/158 = 20 % (Fig. 2)

    Fig. 2
    figure 2

    Cobb angle results with SRS criteria. 80 % of scoliosis are stable or improved more than 5°

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Clinical frontal balance is significantly improved (6mm).

Although non statistically significant, clinical sagittal balance is worsened 6mm.

There is no significant difference at the clinical rib hump, which is favourable because the spontaneous evolution would be in the direction of worsening (Fig. 3).

Fig. 3
figure 3

Clinical parameters results. Significant improvement of the frontal occipital axis, worsening of sagittal imbalance and stability of the rib hump

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The analysis shows that 18 scoliosis have increased by more than 10°, in 8 cases, the brace was no longer worn, but in 10 cases, it was worn at least 4 h a day. It is, therefore, true that there are failures. It’s not only a compliance problem as in 28 cases, the brace is not worn and the scoliosis remained stable.

There was also 1 suicide, but as a result of breast cancer.

Discussion

Bracing adult lumbar and thoracolumbar painful and instable scoliosis with polyethylene bivalve overlapping brace is effective. The aim of the treatment is a disk protection and a three-dimensional re-equilibration of the spine. We have shown in preliminary work that this treatment despite the plaster cast is well accepted with only 17 % of drop out (Fig. 4).

Fig. 4
figure 4

Distribution of 739 adult scoliosis with rigid bracing indication. Non-adherent patient’s rate is 17 %. 21 % of patients were monitored 5 years after the start of treatment

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As in all publications, pain is improved by wearing the brace, but bracing is not only palliative, it’s a real treatment of lumbar instability mainly by discharging the pressure in the disc and stabilizing the lumbar area in lordosis to restore the tensegrity of the spine.

The results show that 8.5 years after the beginning of treatment, the natural angular evolution of scoliosis is halted in 80 % of cases.

However, it appears that current braces fail to stop the kyphotic evolution of adult scoliosis and justifies the improvement of existing braces.

Despite the undeniable technical progress, all adult scoliosis do not have an indication for surgery and adult rigid bracing appears to be a reliable alternative.

Conclusions

Adult rigid bracing is not only a pain killer. When treatment is carried out rigorously, it can stabilize the evolution of scoliosis in 80 % of cases during 8 years. Frontal balance is significantly improved. Although not significant, sagittal balance worsened and justifies the use of new braces.