Scoliosis and spinal deformity — formative SAQs

SAQ 1 (10 marks) — The 12-year-old girl with a 32-degree curve and a red flag

Stem: A 12-year-old girl is referred by her school nurse for a spinal curve. She has a LEFT thoracic prominence and complains of intermittent mid-back pain. On examination the Adams forward bend test shows a rib hump, and the abdominal reflexes are asymmetric. The standing radiograph shows a 32-degree left thoracic curve, Risser 0. Outline your assessment, the red-flag screen, the investigation strategy, and the management. [2]

Model answer

Assessment and the red-flag screen (3 marks). This is a 12-year-old with a spinal curve, but the features break the pattern of the typical idiopathic curve. The idiopathic curve is painless, right thoracic, and carries a normal neurological examination. This girl has three red flags: a LEFT thoracic curve (idiopathic thoracic curves are overwhelmingly right-sided), back pain (the idiopathic curve is painless), and an asymmetric abdominal reflex (a recognised sign of a syringomyelia). The red-flag screen — onset under 10, a left thoracic curve, pain, a neurological deficit, skin stigmata, and rapid progression — is positive, and the curve is non-idiopathic until proven otherwise. [2]

Investigation strategy (3 marks). Because the red-flag screen is positive, the investigation adds a magnetic resonance imaging of the neural axis before any bracing, to exclude a syringomyelia, a Chiari malformation, a tethered cord, and a spinal cord tumour. The standing posteroanterior radiograph has measured the Cobb angle at 32 degrees and staged the maturity at Risser 0 (substantial growth remaining). The asymmetric abdominal reflex and the left thoracic pattern make the magnetic resonance imaging mandatory, and the finding on the imaging redirects the management from the brace to the neurosurgical and the spinal intervention. A renal ultrasound and an echocardiogram are added if the imaging suggests a congenital or a syndromic cause. [2]

Management (4 marks). The management follows the imaging. If the magnetic resonance imaging reveals a syringomyelia or a Chiari malformation, the child is referred to the neurosurgical team for the management of the neural-axis lesion, and the bracing and the elective fusion wait until the cord is secured. If the imaging is normal, the curve is re-classified as idiopathic and placed on the ladder by the two numbers — the 32-degree magnitude and the Risser 0 maturity — which would indicate bracing (25 to 40 degrees while growing). The family is counselled on the diagnosis, the natural history, the treatment options, and the safety-net, and the follow-up is arranged. The key teaching point is that the red flag is examined and the imaging obtained before the brace is fitted. [2] [9]

SAQ 2 (10 marks) — The five-year-old with a progressive early-onset curve

Stem: A five-year-old boy is referred with a thoracic curve that has progressed from 25 to 45 degrees over 18 months despite observation. He is neurologically normal. Discuss why his management differs from that of an adolescent with the same curve size, the principle of the growth-friendly strategy, and the goal of the treatment. [7]

Model answer

Why the management differs (3 marks). This child has an early-onset scoliosis (onset before 10 years), which is fundamentally different from the adolescent curve. First, it is non-idiopathic by default until the red-flag screen and the imaging prove otherwise, and a magnetic resonance imaging of the neural axis is obtained to exclude a congenital, a neuromuscular, or a neural-axis cause. Second, and most importantly, the early fusion of the thoracic spine in a young child would prevent the thorax and the lungs from growing, producing the thoracic insufficiency syndrome — the small chest and the restrictive lung that no later operation fully reverses. The Karol study showed that children fused early in life are left with a reduced vital capacity, greatest in those fused youngest. The adolescent curve, by contrast, largely spares the lung because the thorax is nearly grown. [7] [11]

The principle of the growth-friendly strategy (4 marks). The goal is to allow the thorax and the lung to grow while controlling the curve, rather than to fuse the spine early. The growth-friendly implants are the traditional growing rods, lengthened at planned operations; the magnetically controlled growing rods, lengthened non-invasively in the clinic; the vertebral body tether, a compressive implant on the convex side that modulates the growth and corrects the curve; and the vertical expandable prosthetic titanium rib (VEPTR), which expands the thorax for the chest-wall and the rib-anomaly curve. The C-EOS classification frames the early-onset curve by the etiology, the major curve angle, the kyphosis, and the progression, and it guides the choice of the strategy. The definitive fusion is delayed until the thorax and the lung are mature. [7] [11]

The goal of the treatment (3 marks). The central goal is the prevention of the thoracic insufficiency syndrome and the preservation of the lung growth, alongside the control of the curve and the cosmetic deformity. The child managed well through the early years reaches the adolescence with a larger chest and a better lung than the child fused early, and the repeated lengthenings through the growth are the price of the preserved function. The family is counselled on the diagnosis, the long surveillance, the repeated procedures, and the safety-net, and the multidisciplinary team — the spinal surgeon, the respiratory physician, the physiotherapist, and the anaesthetist — coordinates the care. [7] [11]