The Quarterly Consult is a quarterly supplement to the Bulletin highlighting pediatric clinical expertise. If you have an item of interest to include in the Quarterly Consult, contact Dr. Steve Dassel at 206-625-7373, mailbox 8588.
By Steve Dassel, MD
Wally Krengel, MD, associate clinical professor at University of Washington and director of Spine Services at Seattle Children's Hospital
I discussed scoliosis and spondylolysis with Wally Krengel, MD, associate clinical professor at University of Washington and director of Spine Services at Seattle Children's Hospital.
Q: How common is scoliosis?
A: Between 0.5% and 3% of school age children have a curve of greater than 10 degrees, but only one-tenth of that number have a curve on X-ray that is greater than 30 degrees.
Q: What is the best way to pick it up?
A: The best way is by examining the symmetry of the back and using a scoliometer. The angle of trunk rotation (ATR) degrees are not to be confused with Cobb degrees taken from radiographs.
Q: How many ATR degrees suggest the need for a referral to you?
A: Any number between 3 degrees and 7 degrees will include some false positive and some false negative screening results. The most current recommendation is using 7 degrees on the scoliometer. However, the important thing to remember is that children with smaller ATR measurements may be in the early stages of developing scoliosis, and should probably be followed up with clinical exams in six and 12 months, even if the scoliometer reading is less than 7 degrees. At 7 degrees or more you need to get X-rays.
Q: Do you recommend that all primary care providers use a scoliometer?
Q: What spine films would you like to have us provide?
A: If you are confident that your radiology department will obtain full-length standing films on a single cassette, or digitally spliced, with appropriate shielding and beam collimation, then obtaining standing PA and lateral scoliosis films at the first exam is appropriate. Otherwise it's easier for us to get them at the time of the consultation.
Q: Leg length discrepancy is a common source of back asymmetry leading to a false positive. How do we correct for this?
A: With the patient in a standing position, look carefully for a pelvic tilt by feeling the top of the iliac crests on both sides; a difference of more than one centimeter can be leveled during X-ray and forward bend test to correct for the leg length inequality. However, since most people spend very little time standing at attention with weight evenly distributed on both legs, it is not thought that small degrees of leg length inequality really affect scoliosis.
Q: Other than back asymmetry, what else should we look for on examination with respect to scoliosis?
A: T he vast majority of scoliosis will be "idiopathic." However, secondary scoliosis may occur. Reactive scoliosis occurs when a child has back or abdominal pain, and resolves with this pain. This is most common with spondylolisthesis. The four most common causes of scoliosis other than idiopathic would be Marfan syndrome, Chiari malformation, Charcot-Marie-Tooth disease and neurofibromatosis.
A good physical would include looking for arachnodactyly, flat feet, high arched palate (Marfan), café-au-lait spots (neurofibromatosis), cavus foot, high arch palate and claw toes (Charcot-Marie-Tooth). Assymetric abdominal reflexes suggest spinal cord problems at the thoracic level such as syrinx. Midline spinal dermatologic lesions such as nevi, or dense hairy patches may also overlie a spinal problem. Finally, spine stiffness manifested by awkwardness in forward bending, for example, may be a manifestation of a spinal lesion.
Q: Let's turn to treatment and start with bracing.
A: Let me start by saying that of all the treatments out there, electrostimulation, physical therapy, chiropractic, etc., only bracing and surgery have some reasonable evidence that they affect the natural history of scoliosis positively. Having said that, bracing remains somewhat controversial. The perfect randomized, prospective, double- blinded study of bracing scoliosis, as you can imagine, is nearly impossible to do. There are fairly strong observational cohort studies of bracing that strongly suggest it is effective at stopping curve progression. However, there are substantial downsides to bracing, such as discomfort, inconvenience, social awkwardness for teenagers, and effects on rib cage development and general body image. I would say that most orthopedic spine surgeons will prescribe a brace for patients with a Cobb angle of 25 to 40 degrees because there is nothing else to offer that has very strong data behind it, and families have trouble "doing nothing."
At Seattle Children's we are one of the centers trying to answer the question of the effectiveness and effect of bracing, in a multicenter study called B.R.A.I.S.T. In this study, patients are given extensive information on the pros and cons of brace treatment and then may elect, if they wish, to be randomized to receive brace treatment or observation only. They can also decide that they definitely want or don't want the brace.
Q: When will we have information?
A: The study is in the enrollment stage now. This may take another couple of years, but then answers should come up in a year or so. Obviously, parents are concerned when they bring their children to us and are reluctant to be randomized into a no-treatment group.
Q: At what Cobb angle does function begin to be a problem?
A: Certainly at 70 to 90 degrees. About half of patients with Cobb angles of 80 degrees will have some clinically significant activity limitations related to pulmonary function. Most patients with Cobb angles of 40 degrees or less do not have significant functional problems, or much greater troubles with back pain than the general population without scoliosis.
Q: What are the indications for surgery?
A: Indication for surgery is generally a Cobb angle of greater than 50 degrees. There are some exceptions.
Q: Maturity is based on what?
A: Maturity is based on age, menarche, family growth history and the Risser sign. Bone age films are sometimes obtained in difficult cases.
Q: Do you substitute growth change in the male for menarche?
A: Predicting how much growth remains in a teenage boy is very difficult, as I'm sure you know. The Risser sign is not as reliable, and skeletal maturity can sometimes not be achieved until 18 or 19. Using Tanner signs and establishing whether the peak growth velocity is yet to come or is behind us can be helpful.
Q: Is the Risser sign calcification of the iliac crest?
A: Correct. Full calcification of the iliac apophysis (Risser 4 to 5) is an indication that skeletal maturation has been achieved. If there is no calcification along the iliac apophysis (Risser 0), there is likely a lot of growth remaining.
Q: Is surgery usually successful?
A: Yes, surgery is usually very successful in terms of stopping the progression of curvature and correcting the curve. However, usually the spine cannot be made perfectly straight, and some of the changes in the rib cage shape will remain.
Q: What are the complications of surgery?
A: There is stiffness to the back, but by six months or so, it is reported to feel normal. The patient is out of contact sports for six to nine months. Major complications such as paralysis are very rare, on the order of one in 500 to 1,000 patients.
Q: Let's briefly discuss low back pain and spondylolysis. What is it?
A: It is a stress fracture of the pars interarticularis, usually at L4 and especially L5.
Q: What is this caused by?
A: Repetitive stress on the back, usually hyperextension stress, seen quite commonly in childhood and adolescent athletes - particularly football players, gymnasts, basketball players, and soccer players. This is more likely to occur in patients who have a Scheuermann's kyphosis also.
Q: And what is the treatment?
A: Rest until the patient is pain free, often six weeks to three months. The orthopedist may enforce rest with a brace.
Q: How should the primary provider approach low back pain in children?
A: I'm a bit jaded on this issue because it seems that a very high percentage of patients I see with back pain in adolescence or childhood have a spondylolysis. It almost seems to me like they have a spondylolysis until proven otherwise if their back pain lasts more than a week and interferes with activity. We know that rest and brace is pretty effective in healing of the stress fractures if caught early. I'd prefer that spondylolysis is ruled out with a bone scan or CT scan before prescribing physical therapy. More exercises are not what a stress fracture needs to heal. If there is no radicular pain (nerve-type leg pain, numbness or weakness more typical of disk herniation) and the tests for spondylolysis are negative, then physical therapy and activity as tolerated are appropriate. Scheuermann's of the lumbar or thoracolumbar spine can also cause a lot of chronic back pain and can usually be identified on a simple X-ray. We also see a fair number of kids with disk herniations, but their symptoms are much different, with a predominance of sciatica as opposed to back pain only, and usually radicular leg pain recreated with straight leg raising tests.
The typical non-mechanical, chronic, aching, upper back pain in a teenager that doesn't interfere with activity other than chores, is usually muscular. These kids look and act entirely different than the child with a spondylolysis or disk herniation.
Q: What about MRI, CT and bone scan?
A: While MRI and bone scan are sensitive, they do not tell you the age of the injury, and areas may light up even if several years old. A CT is best to determine if there is an acute stress fracture or stress reaction that will usually heal with brace and rest, as opposed to an older pars defect, which is unlikely to heal with brace and rest.
Q: Finally, the wrap-up question. What mistakes do you see primary care providers making in terms of pediatric spine problems?
A: Failing to follow the very small (2 to 3 degree) ATR curves, which may become problematic several years later. Even small ATR curves should be followed every six to nine months for a while, with just a simple forward bend test, in case they are a real scoliosis that is just being seen at a very early stage. It's very distressing to the parents to have had a child checked and told there was nothing to worry about and then finding a 65 degree curve in their 13-year-old girl a few years later.
Another problem is the use of extensive physical therapy and exercises to treat low back pain before one is certain that it is not spondylolysis, in which case rest and/or a brace would be more appropriate.
Q: Thank you for taking the time, Wally.