Many pathological disease processes are manifested by abnormalities in cellular signalling caused by altered protein expression. Our aims, therefore, were to determine whether ‘’degenerative disc disease’’ results in 1) altered proteome expression and 2) such changes might be used as a marker for the disease process.

Using gel electrophoresis, we analysed the proteome expression of nucleus pulposus (NP) derived from patients with scoliosis (‘normal’) compared to degenerate samples from patients with 1) back pain undergoing spinal fusion (DDD) and 2) sciatica undergoing discectomy (herniated nucleus pulposus or HNP). Normal NP tissue was also obtained from organ donor patients with no previous history of back pain. All samples were investigated in duplicate. Protein concentrations were measured qualitatively by visual analysis in a blinded manner and categorised into high, medium, low or absent. The Kruskal-Wallis analysis of variance was sued to analyse the data. Subsequent proteins of interest were determined on N-terminal protein sequencing.

15 samples each were collected each from scoliosis, DDD, and HNP, but only 4 samples from the organ donor groups. One major protein band difference was observed whose molecular weight was 15 kDa and N-terminal sequence homologous with lysozyme C (lysozyme-C-like-protein - LCLP). DDD and HNP samples exhibited significantly reduced levels of LCLP compared to scoliosis (P< 0.0001). All NP from donor patients exhibited high levels of LCLP, but numbers were too small for statistical analysis. No statistical correlation existed between age and LCLP levels.

The true physiological roles of Lysozyme C remains unclear, but it is a known ubiquitous secretory and hydrolytic protein found in saliva, milk, cerebrospinal fluid and synovial liquid, and thought to function in primary immunity. LCLP loss in degenerate disc tissue might be due to 1) lack of production, 2) increased breakdown through a specific ubiquitin-linked pathway, or 3) polymerisation with tissue-specific amyloid deposition. The inflammatory effects within the NP related to localised LCLP-amyloid deposition offers a plausible hypothesis for patho-physiology of disc degeneration and discogenic pain. Until we determine the true nature and function of LCLP, we are no further in understanding the patho-mechanisms of disc degeneration. Moreover, LCLP loss in the NP of degenerate discs may provide a potential diagnostic marker for degenerative disc disease.

Routine use of Computed Tomography (CT) to evaluate discogram morphology is time consuming, costly and incurs additional radiation hazards. In our spinal unit, discography is routinely performed without the aid of CT. Discogram morphology for different stages of disc degeneration is evaluated using the modified Adam’s grading system on images obtained on fluoroscopy. Our aims were to assess the validity of the modified Adam’s grading system of discogram morphology, by assessing its inter- and intra-observer agreement.

We reviewed the discographic images (133 intervertebral levels) of 71 patients with chronic low back pain undergoing discography as part of a preoperative assessment between 1995 and 1997. Using the modified Adam’s grading system, three independent surgeon observers of three levels of experience (Senior Fellow, Senior and Junior residents) retrospectively evaluated the morphological appearance of each disc level in a randomized and blinded manner. Each observer was supplied with descriptions and illustrations of the 5 grades1, and each level was classified accordingly. The exercise was repeated three weeks later. The respective inter- and intra-observer agreements were calculated using the kappa statistic (Fleiss 1971) and generalized kappa statistic (Landis and Koch 1977).

The inter-observer agreement was excellent (kappa = 0.77; standard error = 0.054). The intra-observer agreement for each of the three observers was also excellent (kappa = 0.8, 0.8, and 0.85 with respective standard errors = 0.046, 0.049 and 0.042).

Significance and conclusions: The inter- and intra-observer agreement and therefore the reliability of the modified Adam’s grading system is excellent. This classification is easy to apply and has a high degree of reproducibility amongst observers with different levels of spinal experience. In view of the high reproducibility, we recommend the Adam’s classification for the grading of discogram morphology. The routine use of computed tomography with the concomitant radiation exposure and additional cost would seem not to be justified.

Objective: This study investigates whether the sequence of anterior and posterior procedure has any effect on the lordosis, disc height and stability in combined A-P fusion of the lumbar spine.

Design: A biomechanical study on cadaver lumbar spine.

Materials and Methods: Twelve motion segments (between L2–L5) from four cadaver lumbar spines were studied. Anterior and posterior stabilization were performed using a Syncage (Synthes, Switzerland) of appropriate sizes, and translaminar screws respectively. Load-deformation characteristics in flexion-extension, lateral bending, and torsion were tested in a material-testing machine (Dartec, Stourbridge, UK) with 7.5Nm cyclical load. Angular deformation of each motion segment was determined simultaneously, by 2-D optical reflex camera system (Pro-reflex, Qualysis, Sweden). Disc height, and angle of lordosis between the adjacent endplates were determined from lateral radiographs. These parameters were measured in the intact spine, after A-P fixation with front first, and after back procedure first.

Results: Compared to the intact spine, the disc height was significantly increased (p< 0.05) when Syncages were introduced before posterior fixation, but not when posterior fixation was done first (p = 0.12). The angle of lordosis was increased significantly with posterior stabilization first, but only marginally, with anterior stabilization first. The stability of the motion segments increased significantly with combined A-P fusion, compared to either anterior or posterior fixation alone. With posterior stabilization first, the stability in all directions were greater but not statistically significant, compared to anterior stabilization first (p> 0.05).

Conclusion: In combined A-P fusion of lumbar spine, the lordosis is better restored when posterior stabilization is done first, but disc height is better restored when the anterior stabilization is performed first. Stability of fixation is not significantly affected by altering the sequence.

Introduction: Despite a very high fusion rate (90%) achievable by present techniques, the clinical success rate for curing back pain is in the range of 50%. We hypothesise that disc degeneration gives rise to abnormal stress patterns in the bone. Although the cages integrate fully, load is taken by the cage producing abnormal stress patterns in the vertebrae. Unless a near normal stress pattern in the vertebrae is established, pain may continue.

Method: A simple finite element model of a disc and its adjacent vertebral bodies was developed using ANSYSS software. The dimensions of the model were based on the human lumbar disc. The normal disc was modelled as a fluid with a bulk modulus of 1720 MPa. The degenerate disc was modelled as having the same material properties for the nucleus and the annulus. Fusion of the disc was modelled by replacing the nucleus with commonly used cages. In all the models, the material properties of the cancellous bone (E=100 MPa; v=0.3) and the cortical bone (E=12000 MPa; v=0.3) remained the same. The model was loaded axially with 1.5 kN.

Results: The vertical and horizontal stress patterns around a loaded degenerate disc showed areas of increased loading in the endplate and the cancellous bone confirming the authors’ previous work using load transducers. The introduction of the cages in the model changed the stress distribution – they caused an increase in the compressive stresses in the cancellous bone, and a high concentration of tensile and compressive stresses at the point of contact with the cages.

Conclusion: This study has shown that fusion cages alter the pattern of stress distribution in the adjacent vertebral bodies similar to that of a degenerate disc. It supports the concept that abnormal weight transfer is a more significant cause of back pain as compared to abnormal mobility.

Three developments in the last 10 to 15 years have made it necessary to review how we ensure rapid access to treatment of patients with disabling low back pain.

Firstly, there would appear to be an increase in the numbers of patients seeking medical help for low back pain, whether due to increased patient expectation, or better reporting, or a true increase associated with the increasing sedentary nature of life, is uncertain. Secondly, there is the realisation that amongst the factors that encourage acute back pain to become chronic is being off work, and the sooner a diagnosis and treatment is started the more likely that chronicity will be prevented, so a long waiting time to be seen in a clinic is productive of disability. Thirdly, reorganisation of consultant services has created the spinal surgeon, who in return for being allowed to practice spinal surgery almost exclusively undertakes the load of patients referred with back pain, amongst whom lurk those with a surgically remediable problem. The effect has been that although waiting times for general orthopaedic patients have dropped, as general orthopaedic, or other specialist orthopaedic surgeons no longer see spinal cases, the specialist spinal surgeon is overwhelmed by a large group of patients with back pain for whom there is not a surgical solution. Unfortunately, there is a shortage of spinal surgeons, which is likely in the UK at any rate to get worse. Being overwhelmed with non-surgical back pain interferes with their ability to deal with surgical problems. It also does create a recruitment problem, as back pain is not seen as a rewarding or satisfying problem to treat.

Triage is a method of screening patients into groups at an early stage, identifying those who might benefit from surgery, and fast tracking them, identifying those who will benefit from other management and tracking them accordingly. Pioneered in general orthopaedics by Robin Ling in Exeter, it has been developed in the hospital setting somewhat randomly, by dedicated enthusiasts, many of whom will be speaking today. The purpose of this meeting today is to hear about the various systems, their funding and organisation and location, the triage staff used, the investigations used in primary triage and the effect on hospital specialist waiting times, the safety and patient satisfaction. Is a multiplicity of systems best, is one better than another, why have some units achieved no waiting times for MRI, and others six months etc?

In 1994, the Clinical Standards Advisory Group produced two books, An epidemiological Review, largely the work of Gordon Waddell, and a second book on Back Pain, chaired by Professor Michael Rosen with, I suspect, considerable input from Professor Waddell and others. Many of us met them when they toured the country collecting facts about the treatment and management of back pain. It discusses back pain triage, and suggests that it can be done within the average GP Consultation time of 9 minutes. It deals with simple back ache, “red flags”, (we now have “yellow flags” denoting the psycho-social factors) nerve root pain, cauda equina and inflammatory disorders. It is to be noted that chronic back pain, is not alluded to in the diagnostic triage, but it is stated that 90% of simple back ache recovers in six weeks. Their management guidelines emphasise the value of physical therapy (manipulation and active exercises), but it will be noted that they are addressed to a group of patients, 90% of whom will recover in six weeks. Sadly, therefore, the effect of this very sensible document, in ignoring in the triage system the chronic patient, has in many cases directed therapy in general practice towards open access for patients who in any event will improve spontaneously.

We must therefore address where triage should be, hospital, or GP level. Certainly a GP gatekeeper will remove the acute back pains that are going to get better soon anyway from attending hospital and in certain units, a separate fast track is provided for acute radicular problems (Acute Sciatic Clinics).

Any successful triage system involving chronic back pain must be associated with treatment possibilities, and I shall briefly discuss these, although the main thrust of the afternoon will be the triage organisation itself.

The session is designed to allow considerable audience participation, as it is hoped that information, comments and criticisms from the audience will allow us to subsequently produce a booklet, hopefully with support from our Professional Societies, describing what we feel is Best Practice in Back Pain Triage, which we hope, after appropriate circulation, will encourage Trusts and Community Health Groups to develop such units and ensure that back pain patients get a better deal.