The Accident Compensation Corporation in New Zealand funds treatment including surgery and rehabilitation for persons injured in NZ including visitors to New Zealand.

It has been operating since 1974 and has been refined in a number of ways since inception.

Its current focus is on early and appropriate treatment, attempting to reduce long-term disability and dependence.


Also discography, a diagnostic test in which radiographic contrast (X-ray dye) is injected into the disc to determine the morphology or state of degeneration.

If done with the patient conscious can be used as a test of pain reproduction. It may be convincing when the doctor injects the dye and the patient says, Yes, that’s the pain.

Not absolutely reliable and a rather unpleasant and painful test. Most patients don’t want to have it again. These days largely superceded by MRI scan although this scan lacks pain reproduction.


A pathological process, as distinct from a degenerative or ageing process.
This is not always distinct!


Diffuse Idiopathic Skeletal Hyperostosis, or Forrestier’s Disease, a stiffening condition affecting the spine, especially in middle aged and older men.

The radiological appearance is like candle wax dripping down the bones due to the ossification of ligaments. (See SPONDYLOSIS)


The parts of the vertebrae adjacent to the discs. Changes within the end plates can affect the nutrition of the disc.



The reverse of flexion. Movement in the sagittal plane, bending backwards, or arching of the back.


Or Patrick’s test, Flexion - abduction - external rotation - extension, a test in which the lower limb is flexed at the hip and knee, then allowed to rotate outwards, stressing the sacro-iliac joint. 


Or ZYGAPOPHYSEAL JOINT, with the intervertebral discs allows movement between the vertebrae.

The orientation of the lumbar facets allows for more movement in the sagittal plane, that is flexion and extension, rather than rotation as between the thoracic vertebrae.

There may be asymmetry of the facet joints (tropism). There may be congenital patterns of facet alignment, which allow excessive movement and subsequent degeneration, e.g., DEGENERATIVE SPONDYLOLISTHESIS.

Facet joints are innervated and may be a source of pain. With facet joint degeneration extension (backward movement) is often painful. Cysts can develop on these joints causing nerve compression.


Bone may be placed on the facet joints to assist in fusion. Screws may be placed across these joints, e.g. fixation as described by Fritz Nagerl in which the screws pass through the base of the spinous process, through the lamina (translaminar) and then across the facet joints.

In my experience this is an excellent method of fixation especially in association with PLIF (Posterior Lumbar Interbody Fusion) over one level. Biomechanically, the addition of such fixation considerably enhances the stability of interbody fusion.

It is generally not rigid enough for two level fusions. There is a very low risk of nerve injury. It is not a method to be used with ISTHMIC SPONDYLOLISTHESIS.

I use Titanium screws 4.5 mm in diameter, with lengths between 20 and 45mm. It is not necessary to place both screws through the spinous processes and in cases with previous laminectomy this may not be possible at all.

It is rare for these screws to require removal. MRI imaging is still possible with these screws in place.


Or as Professor Nachemson puts it, failed back surgeon.

The most common cause of failure of back surgery is failure of indication/s, i.e.; the surgery was not appropriate.

Alternative causes include a failure of patient expectation, technical failures of surgery, e.g., nerve injury, failure to follow postoperative instruction, scarring or recurrence of the problem, e.g., recurrent disc protrusion.


Or foraminal disc prolapse, a disc protrusion within the nerve foramen. 

As there is not much free space within this bony canal the emerging nerve may be severely compressed resulting in much pain. 


A less common variety of disc prolapse where the disc protrudes lateral to the spinal canal and pedicle.

Requires a different surgical approach (the parasagittal approach of Wiltse).


Performed with the patient lying prone (on their front) or on their side. The thigh is extended (straightened) and the knee flexed (bent).

If this causes pain down the front of the thigh the test is positive. Both sides should be tested.


A condition affecting the femoral nerve/s, usually presenting as pain in the front of the thigh, especially in older patients. The pain is often severe and thought to be due to a hip problem.

The skin over the thigh may be hypersensitive or numb, the quadriceps (anterior thigh muscles) are weak, the knee reflex depressed, and the pain is reduced by flexing the hip. The pain is worse if the hip is extended and the knee flexed (FEMORAL STRETCH TEST).

Usually due to a disc prolapse in the mid-lumbar levels, often a FAR LATERAL DISC PROLAPSE or FORAMINAL DISC PROLAPSE. Although the pain can be severe it usually settles within eight weeks.

The Patient may be left with permanent alteration in sensation (MERALGIA PARESTHETICA).


A condition of widespread pain and tenderness, especially around the shoulders, associated with TRIGGER POINTS.

See also PMR (polymyalgia rheumatica).


Metal devices used to hold the spine with fusions, e.g. PEDICLE FIXATION.


Loss of lumbar lordosis, especially after long fusions for scoliosis or occasionally after lumbar fusions done without INTERBODY FUSION or without sufficient lordosis in the FIXATION.

May develope a long time after fusion due to late degeneration of disc/s.


Weakness of the muscles which lift the foot and toes, may be due to a disc prolapse causing compression of the fifth lumbar nerve or due to pressure on the peroneal nerve at the proximal end of the fibula, e.g., strawberry pickers palsy with excessive kneeling.

May also occur in patients in bed due to rotation of the leg. If due to a disc prolapse it may be treated with early surgery. If left untreated recovery may not occur or be incomplete. Surgery on the tendons may help to restore function in selected cases where the disability is prolonged.


A test to detect scoliosis (rotation of the spine). 

Useful as a screening test in adolescents. 

If there is more than five degrees of rotation further investigation should be considered - see SCOLIOSIS. 


The process of joining two vertebrae together. A biological process analogous to fracture healing. May occur congenitally (as failure to separate).

First used in 1911 as treatment of infection. Usually done with addition of bone or bone stimulating substances, e.g., bone commonly is removed from the iliac crests (back or front of the pelvis).

Bone may be placed over the laminae or spines (posterior fusion - not commonly used now except in the cervical spine), between the transverse processes and lateral to the facet joints (posterolateral fusion popularised by MacNab 1955), within the facet joints (especially in fusions for scoliosis) or within the discs (INTERBODY FUSION).


Developed by Dr Henri Graf of Lyon, France, which uses non-elastic bands made of DacronÒ placed over special pedicle screws to stabilize one or more spinal segments - see NEW TREATMENTS. 


Pain in the inguinal region, between the anterior pelvis and front of the thigh, the area in front of the hip joint.

Can be due to inguinal or femoral or other herniae, hip joint disease or referred from the lumbosacral disc or pelvis.

May be due to abdominal inflammation, e.g., appendicitis.

Infections within the abdomen can present as swelling here, e.g., Tuberculosis of the spine. Can be due to disc prolapse in the upper lumbar spine.


History is the most important part of the diagnostic process. What the patient tells us about their problem and their answers to our questions. If the diagnosis is in doubt get more history.

As Sherlock Holmes said to Dr Watson, I must have more data.

Important questions are:

Where is the pain?
Where is the pain worst?
When is the pain worst?
What relieves it?
What makes it worse?
Is it worse at night?
Is it constant? - beware of constant pain that never goes away - it may be due to infection, inflammation or cancer -see RED FLAGS.


A process of uncertain cause, e.g., idiopathic scoliosis.


A method of taking radiographs, often in multiple planes, with the images being shown on a television screen.

Often used in the operating room, e.g. when placing PEDICLE SCREWS or performing BIOPSY or DISCOGRAPHY.


Loss of control of bladder or rectum, may be due to compression of the CAUDA EQUINA.


Fusion within the disc space, between the vertebral bodies - see CAGES.

Bone may be placed in the disc from behind,
PLIF (Posterior Lumbar Interbody Fusion),
from the side or from in front - ALIF (Anterior Lumbar Interbody Fusion)


The ligaments between the spinous processes.

Professor Nikolai Bogduk, anatomist at University of Newcastle, NSW, has written on these.


The plane across the top of the iliac crests.

This usually crosses the L4/5 disc.
In some patients the sacrum is congenitally higher than usual, with the L5S1 disc closer to the intercristal line, and is a predisposition to back pain especially in women in whom the pelvis is wider than in men.



A common type of spondylisthesis where there is a defect in the pars interarticularis, the part between the joints.



Removal of all or part of the lamina, posterior part of the spine, the part behind the nerves and cord -

see DECOMPRESSION - separate entry.


Or Leg Length Discrepancy, a difference in leg lengths. Best assessed clinically by examining the patient standing and feeling the anterior superior iliac spines or the tops of the iliac crests. 

If these are not level objects such as books of different heights are placed beneath the feet until the differences are corrected. Alternatively, for very accurate measurement a CT scan of the lower limbs can be done or special radiographs (Scanograms). 

Where the patient acquires a significant leg length difference, greater than say one centimetre, e.g., after fracture of the tibia or femur, it is important to balance the spine with a shoe raise. Where there is a minor developmental difference correction is often not required. 


Howie is a member of the American Board of Independent Medical Examiners. 

He was the President of the Auckland Medico-Legal Society in 2001. 

He does not prepare medico-legal reports, ACC reports or reviews or Insurance reports. 


Etastasis, plural metastases, secondary spread of cancer beyond its primary site, e.g., to the spine, liver, lungs or brain. Spinal metastases are common in certain cancers, e.g., breast, prostate, renal (kidney), thyroid, lung, and colon.

With some of these aggressive surgical management may be indicated, to reverse paralysis and maintain comfort, especially in the first three, as survival after diagnosis may be long but with lung and colon spinal metastases survival is short.


A noxious sensation, due to an irritation of a nerve.
Spinal pain may have its origin within the spine or it may be referred. Sources of pain within the spine include the outer annulus of the disc, an inflamed or compressed nerve and the capsule of the facet joint.

Muscles and ligaments are not major pain sources by themselves, except as muscle spasm, which is usually a secondary phenomenon.


A collection of experts in different fields,

e.g. anaesthetist, physiotherapist, psychologist, offering a multidisciplinary approach to pain management.


Pedicle, that part of the vertebra joining the posterior elements (facet joints, laminae and spinous processes) to the anterior elements (discs and bodies). In essence a tube of bone with a strong outside (cortex) which is useful for FIXATION - see PEDICLE FIXATION. Lying close to the pedicles are the emerging nerve roots.


Pedicle fixation, a useful method of fixing the spine, by placing screws via the pedicle into the vertebral body, usually done on both left and right sides, connecting two screws in one vertebra via rods or plates onto two screws in another vertebra.

Multiple vertebrae can be fixed in this way or in combination with other fixation e.g. hooks.

Particularly useful where there has been loss of bone from previous surgery or disease. A potential and occasionally real problem with pedicle fixation is the proximity of the emerging nerve roots, which may be damaged by even slight misplacement of such screws.

Careful imaging and experience is required to place these screws safely.


Pelvic pain, pain in the pelvis, e.g., due to conditions such as endometriosis.

Unusual pelvic pains do not usually have a spinal cause.


Poliomyelitis, "polio”, a paralysing infection of the spinal cord. See SUPPORT GROUPS.


Psychosocial factors, factors external to the spine which can affect spinal pain and response to treatment. Beware what I call the eight "Ds”

Dependentlessness, the person who does not have a significant other in their life

Depression, untreated depression is associated with poor outcome from surgery
Disability, where the person requires help in everyday tasks, e.g. dressing, washing
Disemployed (loss of job)
Disputing, where there is dispute with ACC or their boss or their spouse, e.g., divorce proceedings or with the previous surgeon
Distress, where the mental distress is high
Drugs, especially tobacco and morphine
Obesity (yes, I know there’s no D in this), this puts a lot of strain on the spine and makes fusion difficult.


These results are the results of my own surgery. Early results from over ten years ago do not necessarily reflect current expectations.


If you are in doubt or unhappy about the advice given to you seek a second opinion. Of course, a second opinion may be the same, which is reassuring, or it may be conflicting, causing further dilemma. 
Any opinion is just that, an opinion, and no surgeon is infallible. 
There are few "black and white” decisions in spinal surgery and most opinions are a balance of probabilities, expectations and risks.