10 Growth as a Corrective Force

10.1055/b-0035-124595

10 Growth as a Corrective Force

Min Mehta (transcribed by Colin Nnadi)

10.1 Introduction

One of the world’s leading proponents of the treatment of early onset scoliosis, Min H. Mehta, FRCS, made a rare public appearance on September 8, 2011, in Christ Church, Oxford, United Kingdom. Miss Mehta had not given a public talk in the United Kingdom for more than a decade, so it was an honor to have her in our company. She is best known for establishing the importance of the rib–vertebra angle difference as a prognostic index in the evaluation of early onset scoliosis, and she also popularized the casting technique as a treatment option for patients with early onset scoliosis.

What follows is the lecture she presented on that day, edited for print and ease of reading. A summary of the casting technique popularized by Miss Mehta for the treatment of early onset scoliosis is also provided toward the end of this chapter. – Colin Nnadi

I have not progressed very far since my 2005 paper in The Bone & Joint Journal was published because there are many things I still do not know. However, I am quite sure that we must pay attention to the smaller curves when they are small because that is the time when the health care professional can be optimally effective in correction. This is not true for all cases, but it does hold true for many patients.

Scoliosis is a spectrum disorder resulting in varying degrees of deformity (Fig. 10.1). At one end of the scale, curves spontaneously resolve; for a long time, this is where treatment was focused. It is important to understand why the curves resolve. Some progress in a benign, gentlemanly manner, whereas other curves are malignant, rapidly destroying scoliosis. They are a mystery. At the other end of the scale is the dysmorphic group with various associated anomalies. This is the spectrum of curves that we must look at and appropriately treat—that is how I saw it at the time. There are also two distinct phenotypes of scoliosis—namely, the sturdy phenotype (patients will get better) and the slim / slender phenotype (patients will not get better).

**Fig. 10.1** **Fig. 10.1** Scoliosis is a spectrum disorder that results in varying degrees of deformity. R, Resolving; LR, Late Resolving; BP, Benign Progressive; MP, Malignant Progressive.

Examining the child is the first step in the treatment plan. With a very young child, the diaper must be removed. This is absolutely fundamental. As seen in Fig. 10.2a, although the child is being supported, a convex curve is present to the right; the diaper is just about slipping off and is obscuring half of the child’s body. Let the parents handle the child because children trust their parents. A health care professional is a stranger to them. In Fig. 10.2b, the head is rotated away from the side of curve convexity; also note contralateral pelvic tilt.

**Fig. 10.2** (**a, b**) Examination of the child.

Early on, it is important to adopt these very basic patterns in an examination of early scoliosis. The child’s head should be examined because oftentimes asymmetry of the skull is associated with scoliosis (Fig. 10.3). Anteriorly, a slight prominence on the left side and a slight flattening on the right side can be seen and may develop into a severe deformity.

Scoliosis can also affect a child’s face (Fig. 10.4). Although facial asymmetry is commonly seen among the general population, if a child presents to you with a curvature of the spine, pay great attention to the facial asymmetry because this feature indicates that scoliosis is likely to progress, sometimes very rapidly. A short period between appointments is the rule for babies in such a scenario, but not for adolescent patients with scoliosis.

**Fig. 10.4** **Fig. 10.4** Facial asymmetry.

Take note of the femur during the examination. As suggested previously, allow the parent to handle the child. By touching the child only occasionally and talking to the parents, it is likely that the child will become inquisitive and gradually trust you to examine him or her, thus enabling the health care professional to make an early diagnosis.

Fig. 10.5 a shows the image of a broad-backed youngster who is slender; he is already beginning to show a curve on his left side, indicating early scoliosis. Fig. 10.5 b is the image of a child without scoliosis, but the child is slightly lordotic; therefore, it would be prudent to follow-up with him to ensure that a curvature does not develop.

Assess the flexibility and rigidity of the curve. Floppiness and hypotonia are well-known features. When you are observing and palpating these features, let the parent do the work for you—an approach that is simple and offers a greater picture of what is happening with the child’s spine.

There are many different features of scoliosis. There are hypotonic floppy children, and there are some children with spasticity—a gibbus or joint laxity is quite often seen in these children. Resisting head rotation to the curve convexity (i.e., the child does not like going to the right side because the entire spine is being moved) is a relatively regular feature. Furthermore, and perhaps most importantly, there are other idiopathic anomalies—at least in the sense that nothing is obvious.

Ensure that the baby is lying down and being handled by the parent. Note the degree of asymmetry; the head will tilt to one side, while the pelvis will tilt to the other. There may also be a hint of scoliosis on the left side, with the head rotated in the contralateral direction. (These are features seen regularly but not always recorded.)

During a radiographic evaluation, there are rather obvious things that health care professionals must do. Do not stretch the patient’s arms when obtaining radiographs because doing so reduces the curve (Fig. 10.6). As mentioned previously, the best way to perform this task is to let the parents gently hold the child with his or her arms outstretched.

**Fig. 10.6** Optimal position for X-ray evaluation.

Fig. 10.7 presents radiographs of two children whom I met years ago in the maternity ward. There is a rotatory element. One child is 2 months of age, and the other is aged 6 months. In the 1970s, the medical community was not quite sure what to do with them. My training seemed to suggest that the 2-month-old child must have a very severe curve. The curve in the 6-month-old child was 14 degrees. After reviewing their records and assessing the patterns, I found that the 14-degree curve was likely to progress, while the other one was likely to resolve. I also performed a small series to understand what was happening to the growing spine, taking the series right through the stages so that some of the people were older (ranging from 12 to 51 years of age).

**Fig. 10.7** (**a, b**) Radiographs of a 2-month-old and 6-month-old.

And in those days, health care professionals paid no attention to the rotation of the curve; by contrast, it was the degree of the Cobb angle that was important. However, curves sometimes looked innocuous, but quite a lot of rotation was present. Two curves can be seen; the first one is the little curve, there is a small blob, which is the transverse process, and the second one above it is the body (see Fig. 10.7). Rotating them at 15-degree intervals changes the picture, and quite often, it is the rotation that leads to severe problems in the future.

As the picture moves from 30 to 45 degrees of rotation, a straight back can be seen at 60 degrees, and the curvature is then absent because of rotation. Therefore, it is crucial that health care professionals pay a great deal of attention to the rotatory element when they examine children with scoliosis.

The spine of the 2-month-old infant shows a 6-degree difference in the rib–vertebra angle compared with the spine of the 6-month-old child (see Fig. 10.7). Although the curve was larger, it was definitely hidden. The curve of the 6-month-old child is worse because it had a large rib–vertebra angle difference (RVAD). The age of 6 months is the point in time when treatment should begin.

The 14-degree curve following treatment is revealed in Fig. 10.8a, and the other child’s spine, which grew straight, is shown in Fig. 10.8b. Therefore, the Cobb angles are not the only indicators to look for.

**Fig. 10.8** (a) Fourteen degree curve in a 6-month-old. (b) Resolving curve in 2 month old (RVAD is less than 20). (c) Eighty-three degree curve in a 4-year-old.

Curves as severe as this can—and do—occur. Refer to the degree of rotation. The spine is badly rotated, and once rotation is present, no amount of surgery or novel techniques will normalize the alignment of the spine.

At what stage can health care professionals discern what is going to happen? The rib–vertebra angle is important in the early differentiation of resolving and progressive curves because this angle may help determine which curve will do what. Once the rib–vertebra angle is known, the health care professional can establish which curve may resolve and which may progress, and therefore which curve will require early treatment. For example, a curvature with a large difference between the rib and spine is not likely to resolve. The angle of the rib to the spine also gives the health care professional a rather clear prognosis of what will happen. If the rib–vertebra angle is less than 20 degrees, then the curve may be likely to resolve, provided that the child is treated early.

Radiography is also important and should be obtained at 3 months, then repeated no more than 2 months after the initial radiograph.

In progressive scoliosis, the RVAD is usually more than 20 degrees, and it may remain the same or increase within 2 months. Conversely, in resolving scoliosis, the RVAD is less than 20 degrees and gets better after 2 months; therefore, the RVAD is very important. Treatment is appropriate when it is apparent that the RVAD has been increasing after 2 months. Waiting any longer than this means that it is too late for treatment.

Case Study

In the case of one child who was 3 months of age, the rib–vertebra angle was measured, and there was symmetry of the rib cage. However, when the child was 5 months of age, a curve that looked relatively benign could be seen, but the parents were fearful because the rib–vertebra angles were asymmetric. At 7 months and 8 months, the curve looked worse, and by 1 year it was much worse. At this point, palliative treatment was likely to be the only option. This case serves as a warning—that is, the more appropriate action to take is to begin watching these children much earlier than the medical profession does now, and to do so more frequently, because children grow fast. At the first sign of deterioration, health care professionals should take action. After that point, it is often too late. Every clinician is different, and so is every child; children do not conform to a specific rule, so treatment must be individualized to prevent the development of scoliosis.

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