Scoliosis is a lateral curve of the spine.  Scoliosis is monitored by measuring the angle on the X-rays.   This is called the Cobb angle, which measures a two dimensional angle. Scoliosis is a three dimensional pathology as there is a twist of the spine. The Cobb angle therefore is a poor measure of how scoliosis affects the spine.

Scoliosis can be classified by its causes and the age of onset.

Idiopathic Curves are curves that occur without any other pathology and therefore the cause is said to be unknown. There is usually a genetic predisposition. Idiopathic can be split into early onset (infantile and juvenile) and adolescent.

Early Onset Curves can affect long term respiratory function, by preventing the lungs from developing. Normal Adolescent Idiopathic Curves do not depress respiratory function significantly and operating on older children with scoliosis does not improve lung function.

If a child has a neuromuscular disorder such as spinal muscular atrophy, spina bifida, muscular dystrophy etc. then then these conditions can affect the spine, all for different reasons.  The outcome in scoliosis surgery here may be to provide a good sitting balance in a wheelchair in the long term and prevent poor sitting balance which leads to pelvic obliquity and can lead to dislocated hips which is painful.  Each of the neuromuscular disorders have their own problems, for example, muscular dystrophy (MD) patients have significant cardiac abnormalities. Recent advances have been the increased longevity of life in MD patients, due to treatment with steroids as soon as the child starts to have difficulty walking.

Spinal muscular atrophy (SMA) patients tend to require growing rods, some of them at an early age. Recently developments in the medical management of SMA include injections into the spinal column.   Nusinersen could be a big breakthrough in the treatment of these patients.    The injections are given into the thecal sac (the spinal column) and results show that this treatment can delay the progression of weakness which occurs in MSA.  A fusion of the spine may prevent the delivery of such treatment, therefore compromising the child’s future – an area of non-fused spine therefore needs to be retained in order to allow this drug to be delivered into the spinal canal.

Most cases of cerebral palsy are due to anoxia of the brain.   Along with spasticity, a progressive scoliosis occurs.   Not all cerebral palsy children with large curves require treatment, decision making in this group of patients is often difficult, usually the child has little or no understanding.

Curves progress either because of the deterioration in the child’s pathology. In idiopathic curves, once the child has stopped growing, the curve is almost static for many years. There is usually a late deterioration which occurs most often in the fifties or sixties.   Surgery in patients in their sixties and seventies can be as a result of a missed adolescent curve or can be as a result of de novo degenerative scoliosis that occurs later in life.

of the disc. It causes deformity and severe pain.  Unfortunately, surgery for this group of patients is complex and has a high complication rate.  This is partly as a result of the fact that the spinal deformity is harder to correct but also because of the co-morbidities of the patients.   These patients are not syndromic (in that they do not have neuromuscular conditions) but they have heart and lung restrictions.   There is a much higher risk of complications compared with children’s scoliosis surgery.

Bracing is useful in infantile and juvenile curves but seems less helpful in adolescent curves.  Bracing, to be effective, needs to worn eighteen plus hours a day.

Compliance is always a problem in bracing studies have demonstrated that the time wearing a brace differs dramatically from the time it is reported that the brace is worn.  Children do not like wearing braces at school, as they are teased.

An indication for surgery may be failure of the brace to hold the curve, a progressive curve or a curve that is causing significant functional or “cosmetic” problems.

There are a number of surgical options when treating patients with scoliosis.  Most of these options depend on the cause of the scoliosis.  The most common operation would be a posterior spinal correction with rods and screws. If the child is young and is still growing these would be growing rods, which are rods that can extend. For the last decade MAGEC rods were a popular option as after the surgery to insert the rods and screws the patient is then lengthened using magnets in out-patients.  The MAGEC system has just lost its CE mark due to issues which include there being problems with the lengthening driving motor, and issues related to long-term safety of the device.  There is no sign of a replacement for this device.

Traditional growing rods are rods that are inserted and then lengthened surgically every six or so.  This requires multiple general anaesthetics and is unpopular with families.  A child who has to undergo recurrent lengthenings misses a considerable amount of time off school over the years, as often they will have ten or more lengthenings, requiring a week or two off school each time.

In adolescence, the traditional Gold Standard in this country is for posterior fusion of the spine.  This allows correction of the deformity with rods and screws, which hold the spine in a satisfactory position while the bone fuses up to become one long bone.  Recently, Vertebral Body Tethering (VBT) has been championed, as a way of correcting the spinal deformity at the same time as maintaining spinal range of movement.  This has the potential advantage of reducing stiffness, increasing agility, and reducing the potential risk of degenerative disc disease in the lower lumbar spine if a curve has to be corrected down to L3 or L4.  Unfortunately, NICE which controls the funding for surgery has not allowed funding for VBT, although they have said that once appropriate trials have been reported in the literature with peer group publications demonstrating that it is safe and effective, they will fund its use in the NHS.

Because VBT is publicised essentially by the media, it is a source of great frustration to both clinicians and parents.  The clinicians in the UK are unable to provide treatment, whereas the families look upon VBT as being the Holy Grail.  A number of surgeons in the UK have been trained abroad to do VBT surgery.  It is practised in the USA, Turkey, and parts of Germany.  Families have used crowd funding in order to obtain finances.  A number of patients have gone abroad for VBT.  Not all surgery has been successful, there have been some post-operative problems.  There is a significant learning curve related to vertebral body tethering surgery because the surgery involves accessing the anterior spine which most spinal surgeons are less familiar with.   Vascular injuries have occurred.

The risks related to spinal surgical correction differ with each cause.  For example, in surgical treatment of muscular dystrophy there is a small anaesthetic risk of Cardiac Arrest during surgery.  This requires cardiac optimisation prior to the surgery.

Congenital Scoliotic Deformities carry a higher risk of paralysis.  This may be partly because they may have an abnormal spinal cord to start with.

The risk that all spinal surgeons fear most is the risk of paralysis which if the MRI scan is normal is about 1 in 700.  Paralysis can occur as a result of a misplaced screw damaging the spinal cord.  It is accepted that there is a small risk of misplaced screws. Therefore, in clinical negligence cases it is important to ask the question – why was this particular screw misplaced? and what precautions did the surgeon perform in order to try and prevent a misplaced screw being so misplaced that it damaged the spinal cord?

In the early post-operative phase, paralysis can occur due to a Spinal Cord Infarct.  Once a Spinal Cord Infarct has occurred the neurological deterioration cannot be reversed, however in the early stages of a spinal cord infarct or where there is spinal cord compression if this is detected early, then it can be reversed in some cases.  It is therefore extremely important to perform Neurological Observations regularly in the first forty eight hours post op.  Most theatre protocols require the neurological function of the child to be checked before the child leaves theatre.

Occasionally a wake up test is required.  During surgery the child is woken from surgery and asked to move their legs.  This sounds gruesome but the child usually does not remember it. Cases have been won where a wake up test was not performed.

Blindness is particularly feared. This can occur in any patient having a general anaesthetic but is more common in spinal surgery.   It is said to occur in about 1/3000 cases.  It occurs when too much pressure occurs on the face during the surgery. The patient is prone (lying on their tummy during the surgery) and the face is protected and monitored by the anaesthetist. Special pads are available to reduce any pressure near the orbits.

Consent is always controversial in scoliosis surgery as often we are dealing with a child. Most children however can participate in their decision making, especially if they are twelve years or over.  A child who is adequately prepared prior to the surgery has an easier post-operative recovery than those who do not understand the surgery or the reasons for the surgery.  It is usually a family decision. It would be very unusual to force a family who did not want scoliosis surgery – the Courts are very rarely if ever used to gain consent.

Consent in scoliosis surgery is an ongoing process, often over a number of visits to the clinic while the curve is being monitored. It is unusual for a patient to be seen in clinic,  immediately listed for surgery and operated on quickly.

Screws are put in pedicles during the surgery. The pedicles are pieces of bone varying in diameter from about 3½ mm up to about 15 mm depending on the size of the patient. Screws vary in width from about 3½ mm up to 6½ mm.

When screws are inserted, it is usual to perform some form of imaging. This allows the surgeon to identify which levels the screws are being put in and the position of the screws. Misplaced screws can cause a neurological problem and very rarely a misplaced screw can risk a vascular problem.  During insertion of the screws the tract that the screw follows is felt to try and identify any potential misplacement.

There is always a small risk of infection, the risk in an adolescent idiopathic (low risk) is 1-2%.  The risk in neuromuscular cases can be much higher and in revision or growing rod lengthening cases can be higher still. Metalwork is normally left in situ once the spine has fused. Studies show that about 90% of patients do not need their metal removed in the longer term.

Traditionally, scoliosis surgeons are orthopaedic surgeons.    Most scoliosis surgeons do nothing but spinal surgery, though occasionally they also have trauma commitments.   One or two surgeons would call themselves paediatric orthopaedic surgeons rather than spinal surgeons, so they will do hips as well as spines in children.   One or two scoliosis surgeons are primary neurosurgeons but their main interest tends to be the degenerative scoliosis rather than the paediatric scoliosis.

Because patients develop co-morbidities as they get older, the risks to patients in treating degenerative scoliosis is much higher.  Firstly, there are general risks such as wound healing which is more of a problem in 70 year olds than in children.   Because the wounds do not heal as well, there is a higher risk of wound breakdown and wound infection.   There are then other co-morbidities such as problems related to heart and lungs, and a risk of stroke.

In children’s scoliosis surgery, the risk of DVT and pulmonary embolus is virtually unheard of, whereas the risks in degenerative scoliosis are high with a pulmonary embolus rate being significant, despite prophylactic treatment.

In general, in children’s scoliosis surgery, the risk of death only relates to the risks related to the other co-morbidities of the syndromes they have.   In adult degenerative scoliosis surgery, however, there is a risk of death due to stroke, pulmonary embolus, etc.   This all needs to be fully discussed.   Scoliosis surgery in later life never improves quantity of life, can improve quality of life but equally when things go wrong, they can significantly reduce quality of life.  The risks related to paralysis, blindness, etc are all similar to children’s scoliosis surgery.

Intra operative navigation to try and prevent screw misplacement is on its way.   This can be combined with robotic modules, which may reduce length of time and may increase the accuracy of the surgery.   Such devices, however, rely on the intra operative CT scanning or pre-operative CT scanning.

Genetic engineering may help prevent scoliosis or prevent the diseases associated with scoliosis.

Other growth guidance systems similar to vertebral body tethering will probably be developed.

Because intensive care units are becoming more skilled at preserving children’s lives, the number of patients with unusual scoliosis associated with syndromes has increased.   There are therefore increasing numbers of children coming through with curves, who would not have survived ten or twenty years ago, who are now presenting needing surgery.   This increases the demand on intensive care units.   These patients tend to have a higher complication rate because of their co-morbidities.

About the Author:

Mr Jonathan Spilsbury, FRCS FRCS(ORTH), is a Consultant Orthopaedic Spinal Surgeon. He continues to work in the NHS at the Royal Orthopaedic Hospital and Birmingham Children’s Hospital. He has taken part in the Birmingham Spinal On-call service for nearly 20 years, and still contributes to this by giving advice to colleagues.

Having practised all aspects of adult and paediatric spinal surgery, his specialist interest is spinal deformity surgery, including the treatment of children with scoliosis, kyphosis and congenital anomalies as well as covering spinal emergencies including trauma, infection and spinal tumours.

He started in medicolegal practice more than 30 years ago, and continues to be involved with all aspects of spinal injury, and advises on negligence cases. He has a busy medicolegal practice, and advises for both Claimants and Defendants.

Mr Spilsbury can be contacted at jonathanspilsbury@inneg.co.uk for all medico-legal enquiries