A critical analysis of evidence for using sham surgery in Parkinson's disease: implications for public health

Sham Surgery in Orthopedics: A Systematic Review of the Literature

Objective

To evaluate the evidence for the effectiveness of sham surgery in orthopedics by conducting a systematic review of literature.

Methods

Systematic searches were conducted on Biomed Central, BMJ.com, CINAHL, the Cochrane Library, NLM Central Gateway, OVID, ProQuest (Digital Dissertations), PsycInfo, PubMed/Medline, ScienceDirect and Web of Science. Secondary searching (PEARLing) was undertaken, whereby reference lists of the selected articles were reviewed for additional references not identified in the primary search. All randomized controlled trials comparing surgery versus sham surgery in orthopedics were included. Data were extracted and methodological quality was assessed by two reviewers using the Critical Review Form-Quantitative Studies. Levels of scientific evidence, based on the direction of outcomes of the trials, were established following the Australian National Health and Medical Research Council (NHMRC) Hierarchy of Evidence (Australian National Health and Medical Research Council, 1999).

Results

This review includes six randomized controlled trials (RCTs) involving 277 subjects. All six studies were rated as very good on methodological quality. Heterogeneity across the studies, with respect to participants, interventions evaluated, and outcome measures used, prevented meta-analyses. Narrative synthesis of results, based on effect size, demonstrated that sham surgery in orthopedics was as effective as actual surgery in reducing pain and improving disability.

Conclusions

This review suggests that sham surgery has shown to be just as effective as actual surgery in reducing pain and disability; however, care should be taken to generalize findings because of the limited number of studies.

Strengthening the ethical assessment of placebo-controlled surgical trials: three proposals

BACKGROUND

Placebo-controlled surgical trials can provide important information about the efficacy of surgical interventions. However, they are ethically contentious as placebo surgery entails the risk of harms to recipients, such as pain, scarring or anaesthetic misadventure. This has led to claims that placebo-controlled surgical trials are inherently unethical. On the other hand, without placebo-controlled surgical trials, it may be impossible to know whether an apparent benefit from surgery is due to the intervention itself or to the placebo effect.

DISCUSSION

In this paper we investigate justifications for placebo-controlled surgical trials and suggest three measures for strengthening their ethical acceptability. We argue that, given the extent, irreversibility and cost of surgical interventions, there is a need for the best possible evidence about their efficacy. In some cases, the strongest evidence will be from placebo-controlled surgical trials, especially where interventions are for outcomes (such as pain) that are likely to elicit a placebo response. In the second part of the paper, we propose three specific measures to increase the ethical acceptability of placebo-controlled surgical trials. The first is structured consultation with the relevant patient community about the risks and benefits of particular placebo-controlled surgical trials. The second seeks to address the therapeutic misconception through the use of educational materials, informed by patient consultation. Finally, we argue for ethical consideration of non-surgeon clinicians who are necessarily involved in the delivery of placebo-surgical interventions.

SUMMARY

If there is no appropriate surgical comparator and the risks can be reduced to the absolute minimum (given the type of placebo procedure required), and the research has the support of the relevant patient community, there may be grounds for judging that the potential benefits of specific placebo-controlled surgical trials outweigh the risks. If so justified, the ethical acceptability of placebo-controlled surgical trials can be enhanced through using educational measures to address participant vulnerability, and by recognizing clinicians who are necessary participants in the research.

Neural tissue transplantation, repair, and rehabilitation

Transplants of cells and tissues to the central nervous system of adult mammals can, under appropriate conditions, survive, integrate, and function. In particular, the grafted cells can sustain functional recovery in animal models of a range of neurodegenerative conditions including genetic and idiopathic neurodegenerative diseases of adulthood and aging, ischemic stroke, and brain and spinal cord trauma. In a restricted subset of such conditions, cell transplantation has progressed to application in humans in early-stage clinical trials. At the present stage of play, there is clear evidence of clinical efficacy of fetal cell transplants in Parkinson disease (notwithstanding a range of technical difficulties still to be fully resolved), and preliminary claims of promising outcomes in several other severe neurodegenerative conditions, including Huntington disease and stroke. Moreover, the experimental literature is increasingly suggesting that the experience and training of the graft recipient materially affects the functional outcome. For example, environmental enrichment, behavioral activity, and specific training can enhance the recovery process to maximize functional recovery. There are even circumstances where the grafted cells have been demonstrated to restore the neural substrate for new learning. Consequently, it is not sufficient to replace lost cells anatomically; rather, for the grafts to be effective, they need to be integrated functionally into the host circuitry, and the host animal requires training and rehabilitation to maximize function of the reconstructed graft-host circuitry. Such observations require reconsideration of the design of the next generation of clinical trials and subsequent service delivery, to include physiotherapists, cognitive therapists, and rehabilitation experts as core members of the transplant team, along with the neurologists and neurosurgeons that have conventionally led the field.

Is it too soon for mesenchymal stem cell trials in people with ALS?

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease affecting primarily the motor neurons. Stem cell therapy is under development as a possible treatment approach. A pilot study of intraspinal injections of mesenchymal stem cells (MSC) was conducted in 9 participants. We review this paper, the rationale, preclinical data and study design.

CD90 Expression on human primary cells and elimination of contaminating fibroblasts from cell cultures

Cluster Differentiation 90 (CD90) is a cell surface glycoprotein originally identified on mouse thymocytes. Although CD90 has been identified on a variety of stem cells and at varying levels in non-lymphoid tissues such as on fibroblasts, brain cells, and activated endothelial cells, the knowledge about the levels of CD90 expression on different cell types, including human primary cells, is limited. The goal of this study was to identify CD90 as a human primary cell biomarker and to develop an efficient and reliable method for eliminating unwanted or contaminating fibroblasts from human primary cell cultures suitable for research pursuant to cell based therapy technologies.

Potential cellular and regenerative approaches for the treatment of Parkinson's disease

Parkinson's disease is most commonly treated with a range of pharmacotherapeutics, with the more recent introduction of surgical techniques including deep-brain stimulation. These have limited capabilities to improve symptoms of the disease in more advanced stages, thus new therapeutic strategies including the use of viral vectors and stem cells are in development. Providing a continuous supply of dopamine to the striatum in an attempt to improve the treatment of motor symptoms using enzymes in the dopamine synthesis and machinery is one approach. Alternatively, there are tools which may serve to both protect and encourage outgrowth of surviving neurons using growth factors or to directly replace lost innervation by transplantation of primary tissue or stem cell-derived dopaminergic neurons. We summarize some of the potential therapeutic approaches and also consider the recent EU directives on practical aspects of handling viral vectors, cells and tissues, and in the running of clinical trials in Europe which impact on their development.