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Orthopaedic Proceedings
Vol. 92-B, Issue SUPP_I | Pages 219 - 219
1 Mar 2010
Ardern D Cain C Hall D
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Anterior lumbar interbody fusion (ALIF) is an accepted surgical treatment for disabling discogenic pain. Additional posterior fixation has been advocated. This is a prospective clinic al study evaluating a stand-alone anterior fusion cage with an integrated titanium plate and four divergent locking screws.

Patients who had failed conservative management for lumbar discogenic pain were recruited into the study. All underwent diagnostic discography. Surgery was performed through an anterior retro-peritoneal approach. The fusion cage was packed with autogenous bone graft. Outcome measures included: Visual Analogue Scores (VAS), Oswestry Disability Index (ODI) and SF-36 data. Fine-cut CT was performed at one and two years post-operatively. Fusion was defined as continuous bony trabeculae joining the vertebral bodies.

Fifty levels were operated on in 39 patients with a mean age of 40.8 years (22–55). The mean operative time was less than 120 minutes, and mean blood loss less than 100 mls. Radiographic fusion at one year was 78% and 100% at two years. Two year mean VAS sc ores for back pain improved from 7.0 to 3.7 (p< 0.01) and for leg pain from 6.1 to 3.1 (p< 0.01). The mean ODI scores decreased from 50.7 to 31.7 (p< 0.01), and SF-36 (PCS) scores increased from 28.4 to 37.5 (p< 0.01). There were no major complications and no patients have required supplementary posterior fixation.

This technique is safe and is as effective as 360° fusion in achieving fusion in the management of discogenic back pain over one and two levels. This technique has the advantage of avoiding the morbidity associated with additional posterior fixation.


Orthopaedic Proceedings
Vol. 91-B, Issue SUPP_III | Pages 438 - 438
1 Sep 2009
Ardern D Callary S Wilby M Christensen B Vernon-Roberts B Fraser R Moore R
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Introduction: Spondylolysis in skeletally immature individuals is common but only a small proportion of cases develop pain and spondylolisthesis. The pattern of instability and pathologic consequences of surgically created spondylolytic defects have not previously been described. An animal model of lumbar spondylolysis was created using skeletally immature sheep with the aim of observing the intervertebral mobility and pathologic consequences of creating a spondylolytic segment.

Methods: Bilateral spondylolytic defects were created in the fifth lumbar vertebrae of fourteen sheep aged approximately 16 weeks using a posterior surgical approach. Using tantalum markers that were placed in the lumbar spine segments in the vicinity of the lesion, three dimensional translations and rotations in flexion and extension were recorded under general anaesthetic using Radiostereometric Analysis (RSA) at the time of surgery. A novel method of ovine spine manipulation was developed. Briefly, with the animal in a lateral decubitus position spinal extension was achieved by fixing the shoulders and hips in full extension. Similarly, the limbs were brought into apposition to achieve spinal flexion. A control group of seven sheep had tantalum markers only in the same lumbar spine segments. The animals were re-tested under general anaesthetic at six weeks and six months following surgery. After six months the animals were sacrificed and their spines examined using CT and microscopic analysis.

Results: Bilateral spondylolytic defects did not result in significant transverse (x-axis) translation. RSA showed significant differences between the spondylolytic group (mean 1.22°, range 0.30–3.74) and controls (mean 0.28°, range 0.03–0.77)) for rotation in the axial plane (y-axis, p< 0.0025) immediately after surgery. The spines radiologically stabilised over six months.

Discussion: Surgically induced bilateral spondylolytic defects in this immature ovine model result in increased rotation in the axial plane but do not create transverse translation (spondylolisthesis).


In 2002, one hundred and thirty nine patients had their names removed from the orthopaedic surgical waiting list at Taranaki Base Hospital for financial reasons. They fell below the “financially sustainable threshold” for access to publicly funded services. We wished to determine the status of these patients and the effects of this management decision.

All patients were invited to attend clinic for assessment. They completed the SF-36 Health Survey and were interviewed regarding effects of not having surgery. In addition, hips were assessed using Harris Hip Scores and knees were assessed using Knee Society Scores.

These standardised methods of assessment allowed comparisons to be made with overseas data. Our group of patients are experiencing significant impairment as a result of not being able to have surgery. A number of resulting medical and social problems were identified in the course of assessment. Patients also expressed a high level of discontent with the process.

Removing patients who have been assessed and placed on an orthopaedic surgical waiting list is an inefficient means of utilising health resources. It has also been met with a high level of patient dissatisfaction.


Orthopaedic Proceedings
Vol. 87-B, Issue SUPP_I | Pages 32 - 32
1 Mar 2005
Ardern D Mills S
Full Access

Rising health costs have seen increased emphasis on cost containment. Outpatient follow-up after total joint arthroplasty is one such accumulating cost. Enthusiastic recent media interest in failing implants and unacceptable waiting lists adds further interest to the area.

We wished to determine the current post-operative follow-up practices and views of New Zealand Orthopaedic Surgeons. A postal survey was sent to all New Zealand Orthopaedic Surgeons.

The response rate was 83% (131/158). There was wide variation in routine practice and beliefs. For cemented THJRs, 13% of surgeons routinely saw their patients for less than one year, 38% followed their patients for less than five years and 53% continued to see patients indefinitely. Follow-up for uncemented/hybrid prostheses was higher: 8% for < one year, 29% for < 5 years and 59% indefinitely. A system of periodically re-calling patients for x-rays without necessarily seeing them is used by 20% of surgeons.

The most frequent reasons given for follow-up were the detection of osteolysis, wear, loosening and patient symptoms.

Similar figures for total and uni-compartmental knee replacements were reported.

Almost a third of surgeons reported that they were unable to follow-up their patients as they would like to because of resource limitations within the public health sector. 44% believed that future changes in medico-legal expectations will necessitate longer follow-up of patients.

This survey demonstrates wide variation in practice. Higher follow-up rates for un-cemented/hybrid prostheses may reflect uncertainty about the long-term results. There is concern amongst surgeons that their ability to follow-up patients within the public health-care sector is constrained by cost. Periodic questionnaire and x-ray assessment was suggested by many as a possible alternative for long-term follow-up of selected patients. Few surgeons are however presently using such a system. We propose a standard of care.