In recent years, 3D printed custom-made body parts have become reality, and, similarly, there’s been development in bespoke spinal implants
There are many different ways to use these models. One method is a life-size replica of the spine to depict the disease. This can be held and rotated by the surgeon to plan the surgery. The second is to create bespoke implants unique to the anatomy to help guide instruments with precision. The surgeons can also create custom-made bony replacements such as the vertebral body in cancer surgery.
AS is a 40-year-old man who had been suffering with low back pain for many years. He’d undergone many different physiotherapy regimes. An MRI of his back didn’t show any obvious degeneration of the discs. A plain XR revealed an overgrown segment of bone known articulating abnormally with the pelvis. A CT then further helps delineate this and is used to help create a 3D model for surgical planning.
Image 1 shows a 3D model where an overgrown L5 vertebra transverse process has created a painful false joint with the pelvis. Often referred to as a Bertolotti
segment, it can be a common anatomical variant but sometimes can become degenerative and painful. The surgeons involved, Mr Lui and Mr Bishop, utilised the 3D Printed custom model to plan the surgery and use an ultransonic bone scalpel to carefully excise it with minimal blood loss and muscle dissection.
Image 3 shows the X-ray of AHM who was a 12-year-old girl when she was discovered with a double scoliosis — two curvatures of the spine that in some cases can continue to grow in size, causing a progressive deformity such as a rib hump, shoulder height imbalance and a waistline shift. It’s common in young people going through puberty. One of the easiest ways to check if a child has a scoliosis is to perform an Adam’s Forward Bend Test. This is as simple as asking the child to keep the legs straight and touch their toes. We look from behind to see if there’s a hump on the back formed by high-riding ribs and feel for a curved spine.
Surgery for scoliosis can be a complex decision for the child, the family and the surgeon to make. There’s a spectrum of recognised care pathways ranging from observation to braces and scoliosis specific physiotherapy exercises (SSPE — often called Schroth exercises) all the way to various forms of surgery. The age and growth velocity of the child dictates the treatment options (for example, bracing
is only effective in the growing child). Mr Bernard and St George’s Hospital recently published five-year data on a non fusion technique called vertebral body tethering (VBT), with a 95% success at avoiding fusion. However, fusion surgery remains the gold standard.
AHM was growing rapidly and their family decided that they’d prefer to stop the progression early rather than wait for it to get inevitably worse. Image 4 shows a 3D model that was created from the low radiation dose CT Scan. From the life-size model of the spine, specialised jigs were created that would guide the accurate placement of the titanium screws into the spine and help avoid the important structures such as the spinal cord and nerves. Fusion of the spine stops progression of the scoliosis and helps correct the deformity. Image 5 shows the spine after surgery.
Mr Lui recently presented the data on 50 such cases showing that the insertion time and blood loss per screw was significantly lower than free hand techniques allowing more time and concentration on the other important aspects of the surgery. Other methods the team have employed similar to this are the use of navigation or robotic surgery.
Mr Darren F Lui is a fellowship trained complex spinal surgeon and looks after children and adults of all spinal pathology. He works in a highly specialised group practice with Mr Jason Bernard and Mr Timothy Bishop at St George’s Hospital NHS London and privately at Wimbledon Clinics. They cover the HCA Women and Children’s Portland Hospital, HCA London Bridge Hospital, HCA Harley Street Clinic, The London Clinic, Nuffield Wimbledon Parkside Hospital and Spire St Anthony’s Hospital.
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