Paul Slosar

General principles of diagnostic testing as related to painful lumbar spine disorders

Study Design. The literature on diagnostic tests available to the spine clinician for the evaluation of chronic low back pain was reviewed. Objectives. To review critically the available information and data on invasive diagnostic tests used for evaluation of chronic low back pain. Summary of Background Information. Numerous published studies have described the technique and clinical results of diagnostic blocks for chronic low back pain. There are various methodologies, but most lack of an adequate “gold standard” with which to compare the results of the diagnostic test. Methods. The available published studies of diagnostic tests commonly used in the evaluation of chronic low back pain were reviewed, with a focus on invasive techniques. The techniques were evaluated on the basis of the data available to support the conclusions that could be drawn for each of these techniques. The principles of diagnostic testing, including specificity and sensitivity, were reviewed and applied in the context of the data available for each of these invasive tests. Results. The essential features the clinician seeks in a diagnostic test are accuracy, safety, and reproducibility. It is essential to have a gold standard with which to compare the accuracy of a given diagnostic test. There is no completely reliable gold standard with which to compare a diagnostic test (or injection) when the absence of pain is the end point. The clinical setting in which the test is used directly affects the test results. The prevalence of the disease therefore affects the meaningfulness of the test results. Imaging studies have their greatest value in the exclusion of other conditions. These studies alone were not adequate for predicting the patients who would respond to controlled diagnostic blocks of the facet joint. Facet joint diagnostic blockade probably is most accurately performed by median nerve branch block. The greatest specificity for a positive response to a facet denervation procedure is achieved when the diagnosis is established via highly controlled anesthetic blocks. Over the past few decades, the sacroiliac joint has received varying degrees of interest as an important pain generator of low back pain. Despite testimonials to the contrary, no diagnostic physical examination has correlated with sufficient specificity to diagnose this condition reliably from a clinical standpoint. Lumbar discography has been one of the single most controversial subjects in the management of degenerative, painful lumbar spine conditions. The specificity and sensitivity are high for the diagnosis of disc degeneration. The question that revolves around discography concerns the accuracy of this test for the diagnosis of discogenic pain. An integral part of the problem is the lack of an adequate gold standard. In a comparison of nerve root blockade, sciatic nerve block, posterior ramus block, and subcutaneous injection in a cohort of patients with sciatica, the sensitivity of nerve root block was very high, with only a moderate level of specificity. In the case of diagnostic selective nerve blocks used for evaluation of complex or protean nerve compression, surgical confirmation and clinical results should be a reliable gold standard. Conflicting results have been presented depending on the target lesion and method of study. Conclusions. There are inherent limitations in the accuracy of all diagnostic tests. The tests used to diagnose the source of a patient’s chronic low back pain require accurate determination of the abolition or reproduction of the patient’s painful symptoms.

Lumbar spine fusion for chronic low back pain due to degenerative disc disease: a systematic review.

Study Design. Systematic literature review. Objective. To categorize published evidence systematically for lumbar fusion for chronic low back pain (LBP) in order to provide an updated and comprehensive analysis of the clinical outcomes. Summary of Background Data. Despite a large number of publications of outcomes of spinal fusion surgery for chronic LBP, there is little consensus on efficacy. Methods. A MEDLINE and Cochrane database search was performed to identify published articles reporting on validated patient-reported clinical outcomes measures (2 or more of visual analogue scale, Oswestry Disability Index, Short Form [36] Health Survey [SF-36] PCS, and patient satisfaction) with minimum 12 months of follow-up after lumbar fusion surgery in adult patients with LBP due to degenerative disc disease. Twenty-six total articles were identified and stratified by level of evidence: 18 level 1 (6 studies of surgery vs. nonoperative treatment, 12 studies of alternative surgical procedures), 2 level 2, 2 level 3, and 4 level 4 (2 prospective, 2 retrospective). Weighted averages of each outcomes measure were computed and compared with established minimal clinically important difference values. Results. Fusion cohorts included a total of 3060 patients. The weighted average improvement in visual analogue scale back pain was 36.8/100 (standard deviation [SD], 14.8); in Oswestry Disability Index 22.2 (SD, 14.1); in SF-36 Physical Component Scale 12.5 (SD, 4.3). Patient satisfaction averaged 71.1% (SD, 5.2%) across studies. Radiographical fusion rates averaged 89.1% (SD, 13.5%), and reoperation rates 12.5% (SD, 12.4%) overall, 9.2% (SD, 7.5%) at the index level. The results of the collective studies did not differ statistically in any of the outcome measures based on level of evidence (analysis of variance, P > 0.05). Conclusion. The body of literature supports fusion surgery as a viable treatment option for reducing pain and improving function in patients with chronic LBP refractory to nonsurgical care when a diagnosis of disc degeneration can be made.

A Prospective Randomized Comparison of 270° Fusions to 360° Fusions (Circumferential Fusions)

STUDY DESIGN Prospective randomized comparison of anterior lumbar interbody fusion (ALIF) plus transpedicular instrumentation plus posterolateral fusion (PLF) (360 degrees fusion) to ALIF plus transpedicular instrumentation without PLF (270 degrees fusion). OBJECTIVES To compare the clinical outcomes, costs, and utilization of health resources of 360 degrees versus 270 degrees fusions. BACKGROUND The 360 degrees fusion is effective, but its costs and utilization of health resources are high. The PLF often resorbs and may not be necessary. METHODS Before and after surgery pain was measured by the Numerical Rating Scale (NRS), and function was measured by the Oswestry Low Back Disability Index (OSI). Costs were calculated by billing records. Operating times, blood loss, and hospital stays were measured at the time of hospital discharge. RESULTS There were 48 patients: 21 women and 27 men. Mean age was 42 years. Follow-up averaged 35 months (range 24-45 months). In both 360 degrees and 270 degrees fusions, there were significant improvements in NRS and OSI, and the percentage of solid ALIF was high. Only 14% of PLF appeared solid bilaterally and 18% appeared solid on one side only. There were no significant differences in changes in NRS, changes in OSI, or percentage solid ALIF between the 360 degrees and 270 degrees fusions. However, the 270 degrees fusion group had significantly less blood loss, shorter operative times, shorter hospital stays, and lower professional fees, and although hospital charges were lower, this difference was not significant. CONCLUSION Both the 360 degrees and 270 degrees fusions significantly reduce pain and improve function, and there are no significant clinical differences between them. However, there were shorter operating times, less blood loss, lower costs, and less utilization of health care resources associated with the 270 degrees fusions.

Rough titanium alloys regulate osteoblast production of angiogenic factors

BACKGROUND CONTEXT Polyether-ether-ketone (PEEK) and titanium-aluminum-vanadium (titanium alloy) are used frequently in lumbar spine interbody fusion. Osteoblasts cultured on microstructured titanium generate an environment characterized by increased angiogenic factors and factors that inhibit osteoclast activity mediated by integrin α2β1 signaling. It is not known if this is also true of osteoblasts on titanium alloy or PEEK. PURPOSE The purpose of this study was to determine if osteoblasts generate an environment that supports angiogenesis and reduces osteoclastic activity when grown on smooth titanium alloy, rough titanium alloy, or PEEK. STUDY DESIGN This in vitro study compared angiogenic factor production and integrin gene expression of human osteoblast-like MG63 cells cultured on PEEK or titanium-aluminum-vanadium (titanium alloy). METHODS MG63 cells were grown on PEEK, smooth titanium alloy, or rough titanium alloy. Osteogenic microenvironment was characterized by secretion of osteoprotegerin and transforming growth factor beta-1 (TGF-β1), which inhibit osteoclast activity and angiogenic factors including vascular endothelial growth factor A (VEGF-A), fibroblast growth factor 2 (FGF-2), and angiopoietin-1 (ANG-1). Expression of integrins, transmembrane extracellular matrix recognition proteins, was measured by real-time polymerase chain reaction. RESULTS Culture on titanium alloy stimulated osteoprotegerin, TGF-β1, VEGF-A, FGF-2, and angiopoietin-1 production, and levels were greater on rough titanium alloy than on smooth titanium alloy. All factors measured were significantly lower on PEEK than on smooth or rough titanium alloy. Culture on titanium alloy stimulated expression of messenger RNA for integrins that recognize Type I collagen in comparison with PEEK. CONCLUSIONS Rough titanium alloy stimulated cells to create an osteogenic-angiogenic microenvironment. The osteogenic-angiogenic responses to titanium alloy were greater than PEEK and greater on rough titanium alloy than on smooth titanium alloy. Surface features regulated expression of integrins important in collagen recognition. These factors may increase bone formation, enhance integration, and improve implant stability in interbody spinal fusions.

Application of spinal ablative techniques for the treatment of benign chronic painful conditions: history, methods, and outcomes.

Study Design. The literature on current neuroablative techniques for treating benign chronic painful conditions is comprehensively reviewed. Objective. To provide the reader with an understanding of the indications, techniques, and outcomes for the various ablative procedures used to treat chronic pain syndromes. Summary of Background Data. Neuromodulatory techniques are rapidly supplanting the traditional neuroablative procedures used to treat many types of pain. Methods. A MEDLINE search was conducted for each of the following procedures: radiofrequency facet denervation, cordotomy, myelotomy, sympathectomy, DREZotomy, rhizotomy, and ganglionectomy. In the review of each article, special attention given to the outcome, length of follow-up, complications, and number of patients. Summaries of this data were compiled to provided historical perspective, current techniques, indications, and outcomes for each of the aforementioned procedures. The outcomes cited for each procedure generally represent the data from the three or four largest series with adequate follow-up length. Results. The aforementioned procedures have 30% to 90% success rates, with success defined as at least a 50% reduction in perceived pain. These results tend to diminish with time. However, most are associated with a significant degree of morbidity and relatively high complication rates. In addition, many of the techniques lead to deafferentation pain syndromes. Conclusions. Ablative spinal techniques offer pain relief for many patients, but the use of these methods should be considered carefully in the light of available nondestructive procedures that may achieve similar goals with potentially lower morbidities.

Chronic pain of spinal origin

The cost of chronic benign spinal pain is large and growing. The costs of interventional treatment for spinal pain were at a minimum of

Indications and outcomes of reconstructive surgery in chronic pain of spinal origin.

13 billion (U.S. dollars) in 1990, and the costs are growing at least 7% per year. Medical treatment of chronic pain costs

Implant materials generate different peri-implant inflammatory factors: poly-ether-ether-ketone promotes fibrosis and microtextured titanium promotes osteogenic factors.

9000 to

Chronic whiplash and whiplash-associated disorders: an evidence-based approach.

19,000 per person per year. The costs of interventional therapy is calculated. Methods of evaluating differential treatments in terms of costs are described. Cost-minimization versus cost-effectiveness approaches are described. Spinal cord stimulation and intraspinal drug infusion systems are alternatives that can be justified on a cost basis. Cost minimization analysis suggests that epidural injections under fluoroscopy may not be justified by the current literature.

Neuraxial medication delivery

Study Design. Peer-reviewed literature was reviewed and summarized. Objective. To synthesize the indications and published outcomes of reconstructive lumbar spine surgery for the treatment of chronic pain of spinal origin. Methods. A literature review was conducted. Results. The most common indication for reconstructive lumbar surgery is pain that is refractory to nonsurgical treatment. Lumbar fusion has been shown to improve symptoms in carefully selected patients with incapacitating pain. Conclusions. A successful arthrodesis is the fundamental surgical goal for patients with chronic pain of spinal origin. However, a successful fusion does not always correlate with a successful clinical result.