Spinal-fusion surgery - the case for restraint

Transforaminal lumbar interbody fusion: clinical and radiographic results and complications in 100 consecutive patients

OBJECTIVE

We retrospectively reviewed the results of 100 consecutive transforaminal lumbar interbody fusions (TLIFs) performed at one institution. The preoperative diagnoses included degenerative disk disease (55), spondylolisthesis (41; 22 isthmic, 19 degenerative), and degenerative adult scoliosis (4). There were 64 single-level, 33 two-level, 2 three-level, and 1 four-level TLIF (140 levels).

METHODS

The fusion mass was assessed by an independent observer using biplanar radiography, whereas clinical outcomes were assessed by means of several established outcome measures.

RESULTS

By level, the posterolateral fusion was judged to be probably or definitely solid in 78% of levels, whereas the interbody fusion was radiographically solid in 88% of levels, for an overall 93% fusion success/patient (94%/level). All patients had >24 months of postoperative clinical follow-up, and 82 patients (82%) were available for outcome measure assessment at an average follow-up of 34 months (range 24-61 months) postoperatively. Eighty-one percent of these patients reported a >50% decrease in their symptoms, and 76% of patients were satisfied with their results to the degree that they would have the procedure again. However, a large percentage of patients experienced incomplete relief of their symptoms. Twenty patients sustained minor complications, and there were no major complications.

CONCLUSIONS

We conclude that TLIF is a safe and effective method of achieving lumbar fusion with a 93% radiographic fusion success and a nearly 80% rate of overall patient satisfaction but frequently results in incomplete relief of symptoms. Complications resulting from the procedure are uncommon and generally minor and transient.

The rationale for a spine registry

In the discussion about the rationale for spine registries, two basic questions have to be answered. The first one deals with the value of orthopaedic registries per se, considering them as observational studies and comparing the evidence they generate with that of randomised controlled trials. The second question asks if the need for registries in spine surgery is similar to that in the arthroplasty sector. The widely held view that randomised controlled trials are the 'gold standard' for evaluation and that observational methods have little or no value ignores the limitations of randomised trials. They may prove unnecessary, inappropriate, impossible, or inadequate. In addition, the external validity and hence the ability to make generalisations about the results of randomised trials is often low. Therefore, the false conflict between those who advocate randomised trials in all situations and those who believe observational data provide sufficient evidence needs to be replaced with mutual recognition of their complementary roles. The fact that many surgical techniques or technologies were introduced into the field of spine surgery without randomised trials or prospective cohort comparisons makes obvious an even increased need for spine registries compared to joint arthroplasty. An essential methodological prerequisite for a registry is a common terminology for reporting results and a sophisticated technology that networks all participants so that one central data pool is created and accessed. Recognising this need, the Spine Society of Europe has researched and developed Spine Tango, the first European spine registry, which can be accessed under www.eurospine.org.

Bioresorbable polymers: heading for a new generation of spinal cages

The use of polymer-based bioresorbable materials is now expanding to the realm of spinal interbody fusion. Bioresorbable polymers have important advantages over metals, because they are temporary, much less stiff, and radiolucent. Most promising is a group of alpha-polyesters, in particular polylactide acids (PLAs). Their biocompatibility is excellent, and they have sufficient stiffness and strength to provide initial and intermediate-term stability required for bone healing. However, polylactides have characteristics that make them vulnerable to complications if not properly controlled. Degradation rate strongly depends on polymer type, impurities, manufacturing process, sterilization, device size, and the local environment. The fact that larger implants degrade faster is contra-intuitive, and should be considered in the design process. Also optimal surgical techniques, such as careful bone bed preparation, are required for a successful application of these materials. The purpose of this paper is to highlight the specific properties of these bioresorbable polymers and to discuss their potential and limitations. This is illustrated with early preclinical and clinical data.Bioresorbable cage technology is just emerging: their time-engineered degradation characteristics allow controlled dynamization in interbody applications, facilitating spinal fusion. Their radiolucency improves image assessment of fusion healing. Acceptance and use of bioresorbable implants may increase as further research and clinical studies report on their safety, efficacy, and proper usage.

Clinical and radiological relationship between posterior lumbar interbody fusion and posterolateral lumbar fusion

BACKGROUND

Posterolateral lumbar fusion (PLF) is the most popular technique for stabilizing the lumbar spine. Biomechanically, PLF decreases segmental motion in the posterior column, which presumably reduces facet joint pain. Posterior lumbar interbody fusion (PLIF) may decompress nerve roots by distracting the collapsed disc space, and achieving optimal fusion in relation to load-bearing capacity. The purpose of the study was to examine the role of interbody fixation vs pedicle fixation in transverse lumbar fusion and to assess treated and adjacent disc space height changes over time.

METHODS

One hundred patients who underwent PLIF and noninstrumented transverse process fusion (n = 55) or instrumented PLF (n = 45) between 1996 and 1998 were evaluated retrospectively. Outpatient charts and follow-up films were reviewed. Bone fusion was determined using Brantigan and Steffee's classification and clinical outcome by the Prolo scale. Disc space heights at the fusion and adjacent levels were measured. Analysis of variance and chi(2) statistical techniques were used for data analysis.

RESULTS

Disc space height was increased and better maintained in PLIF patients. PLIF resulted in a nonsignificant tendency toward higher fusion rates. No differences in clinical and functional outcomes were found between the groups. There was no correlation between preservation of disc space height and clinical outcome.

CONCLUSIONS

Disc space height does not seem to impact clinical outcome in lumbar fusion, and efforts to maintain it may be unwarranted.

Current treatment strategies for the painful lumbar motion segment: posterolateral fusion versus interbody fusion

STUDY DESIGN

Review of the literature.

OBJECTIVES

We discuss the indications and contraindications for posterolateral lumbar fusion and posterior approaches to lumbar interbody fusion. We also review the advances in minimal access surgical techniques, graft materials, and osteobiologics.

SUMMARY OF BACKGROUND DATA

Previously published data and our own surgical experience form the basis of this report.

METHODS

A Pub Med online internet search for the keywords was performed. The pertinent articles were then cited.

RESULTS

Posterior interbody fusion techniques have theoretical and demonstrable advantages over posterolateral fusion, but the former is also associated with greater morbidity. There are several approaches one may use to perform posterior interbody fusion, as well as multiple minimally invasive techniques and interbody spacer graft options. Bone morphogenetic protein offers an attractive alternative for achieving fusion.

CONCLUSION

Fusion of painful motion segments is widely used to treat patients with degenerative low back pain. Successful arthrodesis may be achieved using either posterolateral fusion with pedicle screw fixation or posterior interbody fusion, depending on the patient's situation. These techniques may be accomplished with a variety of minimal access strategies and various graft and spacer technologies. The modern spine surgeon should be proficient in using all these options to treat the painful lumbar motion segment.

Lumbale Bandscheibenprothesen

Lumbar interbody fusion used to be the most common surgical treatment for painful lumbar disc degeneration. With the technical development of total disc prostheses, replacement of the degenerated disc by a motion preserving implant has become a widely discussed alternative. The advantages of such replacement appear to include the prevention of adjacent segment disease as well as less perioperative morbidity. Three types of total disc prostheses are currently in common use. Although numerous studies have been made, a review of the literature reveals only two multicenter randomized studies comparing the outcome of disc prostheses with a control group of fusion patients. After 2 years, the available results show similar improvement after both types of surgery without significant differences. However, there is a trend towards faster recovery and improvement in disc arthroplasty patients. The long-term results of current and future randomized studies, including studies comparing results after disc arthroplasty, with results of standardized conservative therapies will determine the fate of lumbar disc prostheses.

United States trends in lumbar fusion surgery for degenerative conditions

STUDY DESIGN

Retrospective cohort study using national sample administrative data.

OBJECTIVES

To determine if lumbar fusion rates increased in the 1990s and to compare lumbar fusion rates with those of other major musculoskeletal procedures.

SUMMARY OF BACKGROUND DATA

Previous studies found that lumbar fusion rates rose more rapidly during the 1980s than did other types of lumbar surgery.

METHODS

We used the Healthcare Cost and Utilization Project Nationwide Inpatient Sample from 1988 through 2001 to examine trends. U.S. Census data were used for calculating age and sex-adjusted population-based rates. We excluded patients with vertebral fractures, cancer, or infection.

RESULTS

In 2001, over 122,000 lumbar fusions were performed nationwide for degenerative conditions. This represented a 220% increase from 1990 in fusions per 100,000. The increase accelerated after 1996, when fusion cages were approved. From 1996 to 2001, the number of lumbar fusions increased 113%, compared with 13 to 15% for hip replacement and knee arthroplasty. Rates of lumbar fusion rose most rapidly among patients aged 60 and above. The proportion of lumbar operations involving a fusion increased for all diagnoses.

CONCLUSIONS

Lumbar fusion rates rose even more rapidly in the 90s than in the 80s. The most rapid increases followed the approval of new surgical implants and were much greater than increases in other major orthopedic procedures. The most rapid increases in fusion rates were among adults aged 60 and above. These increases were not associated with reports of clarified indications or improved efficacy, suggesting a need for better data on the efficacy of various fusion techniques for various indications.

A prospective cohort study of surgical treatment for back pain with degenerated discs; study protocol

Background

The diagnosis of discogenic back pain often leads to spinal fusion surgery and may partly explain the recent rapid increase in lumbar fusion operations in the United States. Little is known about how patients undergoing lumbar fusion compare in preoperative physical and psychological function to patients who have degenerative discs, but receive only non-surgical care.

Methods

Our group is implementing a multi-center prospective cohort study to compare patients with presumed discogenic pain who undergo lumbar fusion with those who have non-surgical care. We identify patients with predominant low back pain lasting at least six months, one or two-level disc degeneration confirmed by imaging, and a normal neurological exam. Patients are classified as surgical or non-surgical based on the treatment they receive during the six months following study enrollment.

Results

Three hundred patients discogenic low back pain will be followed in a prospective cohort study for two years. The primary outcome measure is the Modified Roland-Morris Disability Questionnaire at 24-months. We also evaluate several other dimensions of outcome, including pain, functional status, psychological distress, general well-being, and role disability.

Conclusion

The primary aim of this prospective cohort study is to better define the outcomes of lumbar fusion for discogenic back pain as it is practiced in the United States. We additionally aim to identify characteristics that result in better patient selection for surgery. Potential predictors include demographics, work and disability compensation status, initial symptom severity and duration, imaging results, functional status, and psychological distress.

Surgery for degenerative lumbar spondylosis

BACKGROUND

Surgical investigations and interventions account for large health care utilisation and costs, but the scientific evidence for most procedures is still limited.

OBJECTIVES

Degenerative conditions affecting the lumbar spine are variously described as lumbar spondylosis or degenerative disc disease (which we regarded as one entity) and may be associated with back pain and associated leg symptoms, instability, spinal stenosis and/or degenerative spondylolisthesis. The objective of this review was to assess current scientific evidence on the effectiveness of surgical interventions for degenerative lumbar spondylosis.

SEARCH STRATEGY

We searched CENTRAL, MEDLINE, PubMed, Spine and ISSLS abstracts, with citation tracking from the retrieved articles. We also corresponded with experts. All data found up to 31 March 2004 are included.

SELECTION CRITERIA

Randomised (RCTs) or quasi-randomised trials of surgical treatment of lumbar spondylosis.

DATA COLLECTION AND ANALYSIS

Two authors assessed trial quality and extracted data from published papers. Additional information was sought from the authors if necessary.

MAIN RESULTS

Thirty-one published RCTs of all forms of surgical treatment for degenerative lumbar spondylosis were identified. The trials varied in quality: only the more recent trials used appropriate methods of randomization, blinding and independent assessment of outcome. Most of the earlier published results were of technical surgical outcomes with some crude ratings of clinical outcome. More of the recent trials also reported patient-centered outcomes of pain or disability, but there is still very little information on occupational outcomes. There was a particular lack of long term outcomes beyond two to three years. Seven heterogeneous trials on spondylolisthesis, spinal stenosis and nerve compression permitted limited conclusions. Two new trials on the effectiveness of fusion showed conflicting results. One showed that fusion gave better clinical outcomes than conventional physiotherapy, while the other showed that fusion was no better than a modern exercise and rehabilitation programme. Eight trials showed that instrumented fusion produced a higher fusion rate (though that needs to be qualified by the difficulty of assessing fusion in the presence of metal-work), but did not improve clinical outcomes, while there is other evidence that it may be associated with higher complication rates. Three trials with conflicting results did not permit any conclusions about the relative effectiveness of anterior, posterior or circumferential fusion. Preliminary results of two small trials of intra-discal electrotherapy showed conflicting results. Preliminary data from three trials of disc arthroplasty did not permit any firm conclusions.

AUTHORS' CONCLUSIONS

Limited evidence is now available to support some aspects of surgical practice. Surgeons should be encouraged to perform further RCTs in this field.

Papel de la cirugía en la enfermedad degenerativa espinal. Análisis de revisiones sistemáticas sobre tratamientos quirúrgicos y conservadores desde el punto de vista de la medicina basada en la evidencia

INTRODUCTION

The lifetime prevalence of invalidating back pain in general population caused by Spinal Degenerative Disease (SDD) is about 70-80%. Global costs related to this disease are enormous (1-2% gross domestic product). From an Evidence-based point of view, there is a striking discrepancy between the use of many available surgical techniques (especially for spinal fusion) and the lack of scientific support.

METHODS

The authors carefully reviewed all published metaanalysis on SDD therapies up to December 2003. Treatment recommendations were classified according to levels of evidence (strong, moderate, mild or lack of evidence) for both surgical and conservative measures.

RESULTS

Forty-four metaanalysis were selected (nine on lumbar surgery, three on cervical surgery and thirty-two on other therapies). Relating surgery, there is strong evidence favouring early laminectomy in cauda equina syndrome secondary to lumbar disc herniation; discectomy or microdiscectomy are superior to chemo-nucleolysis in lumbar prolapse and spondylosis; and fusion surgery (probably noninstrumented) in adult isthmic spondylolysthesis or degenerative spondylolysthesis with spinal stenosis. In cervical spondylosis and radiculomyelopathy, discectomy seems as effective as discectomy plus fusion, which does not seem to be better than untreated SDD beyond 24 months. Preoperative antibiotics seem to prevent infection in spinal surgery. No benefit of surgery is demonstrated in discogenic pain. None of conservative therapies are supported by strong evidence. Antidepressants improve pain perception but do not influence the functional status.

DISCUSSION

Although lumbar instrumented surgery has nearly doubled over two decades and the annual growth is about 20%, clinical results do not seem to have improved, not even global fusion rates. The increasing use of fusion surgery for cases other than spinal deformities, spondylolysthesis or spinal stenosis plus lysthesis may be related to multiple technical and clinical-epidemiological factors where huge financial and commercial interests must be considered. It is crucial to differentiate subsets of patients prone to benefit from surgery. It is discussed whether randomized trials incorporating sham operations are ethically justifiable, because of the lack of sound evidence for many spinal procedures. The efficacy of most conservative treatments is mild or moderate (mainly transient) and they should be probably used in combination. CONCLUSIONS. There is no strong evidence favouring most of surgical procedures for SDD from an evidence-based approach. It seems necessary that scientific organizations studying SDD create clinical guidelines relating its multidisciplinary and integral management, recognizing that, up to now, few interventions positively modify in the long-term the natural history of the disease.

Intervertebral disc arthroplasty

STUDY DESIGN

Review article of current knowledge of disc arthroplasty.

OBJECTIVES

To review the rationale for disc replacement, the general principles of design, and early clinical results.

SUMMARY OF BACKGROUND DATA

Disc arthroplasty is an emerging treatment for patients with disc degeneration. Its theoretical advantages are to maintain motion, decrease the incidence of adjacent segment degeneration, avoid complications related to fusion, and allow early return to function.

METHODS

Literature review of currently implanted prostheses or those undergoing investigation.

RESULTS

At this time, the theoretical advantages are unproven clinically but have been confirmed in biomechanical and kinematic investigations. Multicenter studies of both cervical and lumbar prostheses have shown short-term results equivalent to fusion. Neurologic complications and failures have been rare. Prosthetic subsidence and long-term wear will most likely be potential failure mechanisms. Thus far, with the exception of nucleoplasty, these problems have not been observed.

CONCLUSIONS

The early results are satisfactory, but the basic premise that motion preservation will diminish adjacent segment degeneration is yet unproven. Long-term results are unavailable and failure modes are unknown. Before implantation, the surgeon and patient must understand the experimental nature of the devices.