The neuropathic component in persistent postsurgical pain: A systematic literature review

Persistent postsurgical pain (PPSP) is a frequent and often disabling complication of many surgical procedures. Nerve injury–induced neuropathic pain (NeuP) has repeatedly been proposed as a major cause of PPSP. However, there is a lack of uniformity in NeuP assessment across studies, and the prevalence of NeuP may differ after various surgeries. We performed a systematic search of the PubMed, CENTRAL, and Embase databases and assessed 281 studies that investigated PPSP after 11 types of surgery. The prevalence of PPSP in each surgical group was examined. The prevalence of NeuP was determined by applying the recently published NeuP probability grading system. The prevalence of probable or definite NeuP was high in patients with persistent pain after thoracic and breast surgeries—66% and 68%, respectively. In patients with PPSP after groin hernia repair, the prevalence of NeuP was 31%, and after total hip or knee arthroplasty it was 6%. The results suggest that the prevalence of NeuP among PPSP cases differs in various types of surgery, probably depending on the likelihood of surgical iatrogenic nerve injury. Because of large methodological variability across studies, a more uniform approach is desirable in future studies for evaluating persistent postsurgical NeuP.     

Prevalence and aetiology of neuropathic pain in cancer patients: a systematic review

Pain in cancer patients remains common and is often associated with insufficient prescribing of targeted analgesia. An explanation for undertreatment could be the failure to identify neuropathic pain mechanisms, which require additional prescribing strategies. We wanted to identify the prevalence of neuropathic mechanisms in patients with cancer pain to highlight the need for detailed assessment and to support the development of an international classification system for cancer pain. We searched for studies that included adult and teenage patients (age above 12 years), with active cancer and who reported pain, and in which a clinical assessment of their pain had been made. We found 22 eligible studies that reported on 13,683 patients. Clinical assessment methods varied, and only 14 studies reported confirmatory testing for either sensory abnormality or diagnostic lesion to corroborate a diagnosis of neuropathic pain. We calculated that the prevalence of patients with neuropathic pain (95% confidence interval) varied from a conservative estimate of 19% (9.4% to 28.4%) to a liberal estimate of 39.1% (28.9% to 49.5%) when patients with mixed pain were included. The prevalence of pain with a neuropathic mechanism (95% confidence interval) ranged from a conservative estimate of 18.7% (15.3% to 22.1%) to a liberal estimate of 21.4% (15.2% to 27.6%) of all recorded cancer pains. The proportion of pain caused by cancer treatment was higher in neuropathic pain compared with all types of cancer pain. A standardised approach or taxonomy used for assessing neuropathic pain in patients with cancer is needed to improve treatment outcomes.     

Evidence for working memory deficits in chronic pain: A systematic review and meta-analysis

People with chronic pain commonly report impaired cognitive function. However, to date, there has been no systematic evaluation of the body of literature concerning cognitive impairment and pain. Nor have modern meta-analytical methods been used to verify and clarify the extent to which cognition may be impaired. The objective of this study was to systematically evaluate and critically appraise the literature concerning working memory function in people with chronic pain. The study was conducted along Cochrane collaboration and Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement guidelines. A sensitive search strategy was designed and conducted with the help of an expert librarian using 6 databases. Twenty-four observational studies evaluating behavioural and/or physiological outcomes in a chronic pain group and a control group met the inclusion criteria. All studies had a high risk of bias, owing primarily to lack of assessor blinding to outcome. High heterogeneity within the field was found with the inclusion of 24 papers using 21 different working memory tests encompassing 9 different working memory constructs and 9 different chronic pain populations. Notwithstanding high heterogeneity, pooled results from behavioural outcomes reflected a consistent, significant moderate effect in favour of better performance by healthy controls and, with the exception of one study, pooled results from physiological outcomes reflected no evidence for an effect. Future research would benefit from the use of clearly defined constructs of working memory, as well as standardised methods of testing.     

Relaxation for the relief of chronic pain: a systematic review

The effectiveness of relaxation techniques in the management of chronic pain was determined in this systematic review of published randomized controlled trials. Reports were sought by searching MEDLINE, psycLIT, CINAHL, EMBASE and the Oxford Pain Relief Database. Studies were included in this review if they were randomized controlled trials of relaxation techniques in chronic pain. Studies which investigated the effects of relaxation in combination with other interventions were not considered. Nine studies involving 414 patients met the predefined inclusion criteria and are critically appraised in this review. Meta-analysis was not possible, due to lack of quantitative data in the primary studies. Studies involved patients with a range of chronic pain conditions. The McGill Pain Questionnaire was the most common pain outcome used. Whilst four studies were able to show a significant difference for the pain outcomes in favour of relaxation for the pre- and post-treatment assessments, few statistically significant differences were reported in favour of relaxation when between treatment comparisons were used. Only three studies reported statistically significant differences in favour of relaxation (judged as a significant difference for at least 1 of the pain outcomes) compared to the other treatment groups. In rheumatoid arthritis the McGill Pain Questionnaire scores were significantly lower for patients receiving relaxation compared to those who were in the routine treatment control group. In ulcerative colitis significant differences were reported for six of seven different pain outcome measures in favour of progressive muscle relaxation compared to patients in the waiting list control group. In one of the two cancer pain studies, relaxation taught by nurses produced significantly lower pain sensation scores compared to the control group. Two studies reported significant differences in favour of the experimental control groups rather than for relaxation. There is insufficient evidence to confirm that relaxation can reduce chronic pain. Many of the studies both positive and negative suffer methodological inadequacies. Recommendations for future research into the effectiveness of relaxation techniques for chronic pain are made.     

Neuropathic pain in the general population: A systematic review of epidemiological studies

Most patients with neuropathic pain symptoms present and are managed in primary care, with only a minority being referred for specialist clinical assessment and diagnoses. Previous reviews have focused mainly on specific neuropathic pain conditions based in specialist settings. This is the first systematic review of epidemiological studies of neuropathic pain in the general population. Electronic databases were searched from January 1966 to December 2012, and studies were included where the main focus was on neuropathic pain prevalence and/or incidence, either as part of a specific neuropathic pain-related condition or as a global entity in the general population. We excluded studies in which data were extracted from pain or other specialist clinics or focusing on specific population subgroups. Twenty-one articles were identified and underwent quality assessment and data extraction. Included studies differed in 3 main ways: method of data retrieval, case ascertainment tool used, and presentation of prevalence/incidence rates. This heterogeneity precluded any meta-analysis. We categorised comparable incidence and prevalence rates into 2 main subgroups: (1) chronic pain with neuropathic characteristics (range 3–17%), and (2) neuropathic pain associated with a specific condition, including postherpetic neuralgia (3.9–42.0/100,000 person–years [PY]), trigeminal neuralgia (12.6–28.9/100,000 PY), painful diabetic peripheral neuropathy (15.3–72.3/100,000 PY), glossopharyngeal neuralgia (0.2–0.4/100,000 PY). These differences highlight the importance of a standardised approach for identifying neuropathic pain in future epidemiological studies. A best estimate of population prevalence of pain with neuropathic characteristics is likely to lie between 6.9% and 10%.     

Factors impacting on doctors’ management of acute low back pain: A systematic review

The aim of this review was to determine the factors that impact on doctors’ management of patients with acute low back pain. A methodological assessment of databases (Medline, EMBASE, Psychinfo, BIOSIS, CINAHL, and the Cochrane Central Register of Controlled Trials) identified papers which were screened for inclusion criteria by two independent reviewers. Data were extracted from accepted papers, and the internal validity and strength of the evidence were determined using valid and reliable scales.The search generated a total of 28 papers [quantitative (n = 27), qualitative (n = 1) methodologies]. Themes were identified from the accepted papers: education (n = 18), knowledge of clinical guidelines and impact on management (n = 7), and doctors’ demographics (n = 4). There was consistent evidence that doctors did not adhere to clinical guidelines when performing a spinal assessment. There was inconsistent evidence that education increased adherence with acute LBP guideline recommendations in terms of referral rates to physiotherapy, for investigations, to secondary care and for maintaining patients at work. Strategies to address the factors impacting on doctors’ management of acute LBP are required; these would lead to improvement in patient outcomes and reduce healthcare costs.     

Factors associated with physical activity participation in adults with chronic cervical spine pain: a systematic review

Objective

To determine the factors associated with physical activity participation in adults with chronic cervical spine pain.

Guidelines on the management of fibromyalgia syndrome – A systematic review

We compared the methodology and the recommendations of evidence‐based guidelines for the management of fibromyalgia syndrome (FMS) to give an orientation within the continuously growing number of reviews on the therapy of FMS. Systematic searches up to April 2008 of the US‐American National Guideline Clearing House, the Scottish Intercollegiate Guidelines Network, the Association of the Scientific Medical Societies in Germany (AWMF) and Medline were conducted. Three evidence‐based guidelines for the management of FMS published by professional organizations were identified: The American Pain Society (APS) (2005), the European League Against Rheumatism (EULAR) (2007), and the AWMF (2008). The steering committees and panels of APS and AWMF were comprised of multiple disciplines engaged in the management of FMS and included patients, whereas the task force of EULAR only consisted of physicians, predominantly rheumatologists. APS and AWMF ascribed the highest level of evidence to systematic reviews and meta‐analyses, whereas EULAR credited the highest level of evidence to randomised controlled studies. Both APS and AWMF assigned the highest level of recommendation to aerobic exercise, cognitive‐behavioral therapy, amitriptyline, and multicomponent treatment. In contrast, EULAR assigned the highest level of recommendation to a set of to pharmacological treatment. Although there was some consistency in the recommendations regarding pharmacological treatments among the three guidelines, the APS and AWMF guidelines assigned higher ratings to CBT and multicomponent treatments. The inconsistencies across guidelines are likely attributable to the criteria used for study inclusion, weighting systems, and composition of the panels.     

Comparison of psychological and physical function in neuropathic pain and nociceptive pain: Implications for cognitive behavioral pain management programs

Research has increased our understanding of the psychological and physical functioning associated with persistent pain and has facilitated the development of cognitive behavioral pain management programs to help improve people’s physical function and decrease their distress in the presence of persistent pain. The majority of this research has focused on nociceptive pain or pain of mixed etiology. There has been less focus on these aspects of neuropathic pain. It is possible that differences exist in the function and difficulties associated with nociceptive and neuropathic pain. These differences may be associated with our clinical observation that some people with neuropathic pain have difficulty applying some aspects of the theory and practice of cognitive behavioral pain management. The purpose of this study was to compare a single neuropathic pain condition (post-herpetic neuralgia) with a persistent pain of nociceptive origin (low back pain) and determine whether differences exist in: (1) physical and psychological function; (2) factors that increase difficulties; (3) responses to pain; (4) beliefs about pain and (5) problems experienced. The results suggest that the differences between the two groups were not on the major variables of pain, mood, cognition and physical function. The main differences were in factors that increase pain, people’s responses to pain, their beliefs about diagnosis and the cause of pain and the problems they reported as a result of experiencing pain. The implications of our findings for the development of cognitive behavioral pain management programs for people with neuropathic pain are discussed.     

Pain neurophysiology education for the management of individuals with chronic low back pain: systematic review and meta-analysis

Pain neurophysiology education (PNE) is a form of education for patients with chronic low back pain (CLBP). The purpose of this systematic review was to investigate the evidence for PNE in the management of pateints with CLBP. A literature search of MEDLINE, CINAHL and AMED was performed from 1996(01)–2010(09). RCT appraisal and synthesis was assessed using the Cochrane Back Review Group (CBRG) guidelines. The main outcome measures were pain, physical-function, psychological-function, and social-function. Two moderate quality RCTs (n = 122) were included in the final review. According to the CBRG criteria there was very low quality evidence that PNE is beneficial for pain, physical-function, psychological-function, and social-function. Meta-analysis found PNE produced statistically significant but clinically small improvements in short-term pain of 5 mm (0, 10.0 mm) [mean difference (95%CI)] on the 100 mm VAS. This review was limited by the small number of studies (n = 2) that met the inclusion criteria and by the fact that both studies were produced by the same group that published the PNE manual. These factors contributed to the relatively low grading of the evidence. There is a need for more studies investigating PNE by different research groups to support early promising findings. Until then firm clinical recommendations cannot be made.     

Doctors' attitudes and beliefs regarding acute low back pain management: A systematic review

The aim of this systematic review was to determine the attitudes and beliefs of doctors to acute low back pain, and the factors that influence these. The review comprised three phases: a methodological assessment of databases (Medline, EMBASE, Psychinfo, BIOSIS, CINAHL, and the Cochrane Central Register of Controlled Trials) identified potential papers; these were screened for inclusion criteria by two independent reviewers, the extraction of data and the rating of internal validity and strength of the evidence, using valid and reliable scales from accepted papers. Themes were then identified from the accepted literature. The search generated a total of 15 papers of both qualitative (n=3) and quantitative (n=12) methodologies. Themes that emerged included doctors' attitudes and beliefs, and four factors that influenced attitudes and beliefs: doctors' specialty, demographic factors, personal beliefs and education. There was consistent evidence that doctors' specialty impacted their attitudes and beliefs: lack of consensus regarding the natural history of LBP, around treatment options, and issues regarding work. There was inconsistent evidence that demographic factors (age) and level of education impacted doctors' attitudes and beliefs. Strategies to address/ modify these attitudes and beliefs are required, as in some cases they are at odds with guideline recommendations. Long term, these changes in these areas have the potential to maximise patient-care, and reduce costs to health services.     

Relaxation techniques for acute pain management: a systematic review

This review aims to document the effectiveness of relaxation techniques, when used alone for the management of acute pain, after surgery and during procedures. A systematic review of randomized controlled trials (RCTs) was undertaken. Seven studies involving 362 patients were eligible for this review. One hundred and fifty patients received active relaxation as the sole intervention. Reports were sought by searching MEDLINE, psycLIT, CINAHL, and the Oxford Pain Relief Database. The outcome measures used were pain and psychological factors. A meta-analysis was not possible, due to lack of primary data. Three of the seven studies demonstrated significantly less pain sensation and or pain distress in those who had relaxation. Four studies did not detect any difference. There was some weak evidence to support the use of relaxation in acute pain. However, this was not conclusive and many of both the positive and the negative studies suffered from methodological inadequacies. Well designed and executed randomized controlled trials are needed before the clinical use of relaxation in acute pain management can be firmly underpinned by good quality research evidence. Until this evidence is available we recommend that the clinical use of relaxation in acute pain settings is carefully evaluated and not used as the main treatment for the management of acute pain.     

Adverse event reporting in randomised controlled trials of neuropathic pain: Considerations for future practice

High-quality information on the potential benefit and harm of a drug is required for patients and clinicians to make informed treatment decisions and to enable cost-effectiveness modeling to be undertaken. This systematic review describes the collection and reporting of adverse event data as presented in published clinical trials of neuropathic pain for the evaluation of antidepressant or antiepileptic drugs. A total of 74 studies in 16,323 patients published between 1965 and 2012 were identified, of which 43 were published from 2004 onwards. The review found that methods used to collect adverse event data, the frequency of collection, and the selection criteria used by authors for reporting adverse events vary substantially, and these events are often inadequately reported. Consequently, a potential synthesis of valuable harm information across trials is hampered. We make recommendations regarding the reporting of methods used to collect, assess, select, and present adverse event data in publications. Through the Core Outcome Measures in Effectiveness Trials (COMET) initiative, core outcome sets (which include effectiveness and harm) are developed by disease condition. To facilitate data synthesis for adverse events of drug therapies, we suggest that core outcome sets for harms could be developed by therapeutic class (ie, individualized for each class of drug). To improve comparability of information across trials collection methods need to be standardized for patient reports (spontaneous or prompted) and active surveillance (clinical examinations and laboratory tests). Uniform methods for presenting summary information regarding recurrent events, duration and timing of events requires further research.     

Prevalence of chronic pain with neuropathic characteristics in the general population

We conducted a large nationwide postal survey to estimate the prevalence of chronic pain with or without neuropathic characteristics in the French general population. A questionnaire aimed at identifying chronic pain (defined as daily pain for at least 3 months), evaluating its intensity, duration and body locations, was sent to a representative sample of 30,155 subjects. The DN4 questionnaire was used to identify neuropathic characteristics. Of the questionnaires, 24,497 (81.2%) were returned and 23,712 (96.8%) could be assessed. Seven thousand five hundred and twenty-two respondents reported chronic pain (prevalence=31.7%; [95%CI: 31.1-32.3]) and 4709 said the pain intensity was moderate to severe (prevalence=19.9%; [95%CI: 19.5-20.4]). Neuropathic characteristics were reported by 1631 respondents with chronic pain (prevalence=6.9%; [95%CI: 6.6-7.2]), which was moderate to severe in 1209 (prevalence=5.1% [95%CI: 4.8-5.4]). A higher prevalence of chronic pain with neuropathic characteristics was associated with middle age (50-64 years), manual professions and those living in rural areas. It was more frequently located in the lower limbs and its intensity and duration were higher in comparison with chronic pain without neuropathic characteristics. This large national population-based study indicates that a significant proportion of chronic pain patients report neuropathic characteristics. We identified distinctive socio-demographic profile and clinical features indicating that chronic pain with neuropathic characteristics is a specific health problem.     

Modulation of sensitized C‐fibers by adrenergic stimulation in human neuropathic pain

The chronic constriction injury model is widely used in studying mechanisms of neuropathic pain. In this model neuropathic pain can be influenced by sympathetic interventions. It is assumed that similar mechanisms as in animals are responsible for pain arising from nerve entrapment syndromes in humans. The aim of the present study was to investigate if in patients with nerve entrapment nociceptive afferents can be modulated by adrenergic stimulation. Methods: Twenty patients with pain due to a unilateral entrapment of the median nerve and 10 controls were included in the study. Spontaneous pain, mechanical and thermal evoked pain were assessed within the innervation territory of the lesioned nerve and the corresponding contralateral segment in patients and on the right hand side in healthy volunteers. The examinations were performed at baseline, during whole body cooling (sympathetic activation) and whole body warming (sympathetic inhibition), and after norepinephrine iontophoresis. Results: All patients reported spontaneous pain. Mechanical allodynia, punctate hyperalgesia and cold allodynia was not found. According to side‐to‐side differences in heat pain thresholds, patients were separated in patients with (n=10) and without (n=10) heat hyperalgesia. Adrenergic stimulation did not induce or enhance spontaneous or mechanical evoked pain in any patient or control subject. However in patients with pre‐existing heat hyperalgesia sympathetic stimulation aggravated heat hyperalgesia significantly. Further in these patients the decrease in heat pain thresholds observed after norepinephrine iontophoresis was significantly higher compared to patients without pre‐existing heat hyperalgesia. Conclusion: Sympathetic–afferent interaction does not play a major role in pain generation due to nerve entrapment. Nevertheless in a subgroup of patients nociceptive afferents show sensitivity to physiological and pharmacological sympathetic stimulation. This finding is important because it emphasises that despite there is no clinical detectable effect on pain sympathetic afferent interaction can be found.     

The burden of neuropathic pain: A systematic review and meta-analysis of health utilities

Patients with neuropathic pain (NeuP) experience substantially lower health-related quality of life (HRQoL) than the general population. The aim of this systematic review and meta-analysis is to test the hypothesis that NeuP is associated with low levels of health utility. A structured search of electronic databases (MEDLINE, EMBASE, Cochrane Library and CINAHL) was undertaken. Reference lists of retrieved reports were also reviewed. Studies reporting utility single-index measures (preference based) in NeuP were included. Random effects meta-analysis was used to pool EQ-5D index utility estimates across NeuP conditions. The association of utilities and pre-defined factors (NeuP condition, patient age, sex, duration and severity of pain and method of utility scoring) was examined using meta-regression. Twenty-four studies reporting health utility values in patients with NeuP were included in the review. Weighted pooled utility score across the studies varied from a mean of 0.15 for failed back surgery syndrome to 0.61 for post-herpetic neuralgia and diabetic neuropathy. Although there was substantial heterogeneity (P < 0.0001) across studies, we found little variation in utility as a function of patient and study characteristics. The single exception was a significant relationship (P < 0.0001) between increasing neuropathic pain severity and a reduction in utility. This study confirms the hypothesis that patients with NeuP experience low utilities and therefore low HRQoL. However, the contribution of non-NeuP co-morbidity remains unclear. Neuropathic pain severity emerged as a primary predictor of the negative health impact of NeuP.     

Chronic pain following donor nephrectomy – A study of the incidence,nature and impact of chronic post‐nephrectomy pain

Chronic pain is a consequence of some types of surgery, but its incidence following open donor nephrectomy has never been investigated. We surveyed 123 patients who underwent open donor nephrectomy at our institution over a 10‐year period, to determine the incidence, severity and nature of chronic pain and its effect on quality of life. Of the 81 (66%) responders, 27 (33%) had experienced prolonged pain, and 21 (26%) still had chronic pain related to their surgery. The overall incidence of severe, disabling pain (visual analogue score ≥7) was 12% and of neuropathic pain was 14%. The average loss in quality adjusted life years (QALYs) was 1.053 for chronic pain sufferers, but was 1.851 for those who suffered specifically from neuropathic pain. Only one third of patients with chronic pain were receiving any treatment, and none were receiving neuropathic adjuvants or specialist pain management interventions. We conclude that the incidence of chronic pain following donor nephrectomy is underestimated and therefore under managed. Given the voluntary and altruistic nature of this procedure, and the enormous personal and social benefits which result from successful donor transplantation, those involved with the preparation and post‐operative management should be more aware of, and actively question donors about chronic pain so that diagnosis and appropriate therapy can be commenced as early as possible.     

Psychosocial predictors and correlates for chronic post‐surgical pain (CPSP) – A systematic review

Chronic post‐surgical pain (CPSP) is a serious problem. Incidence as high as 50% has been reported, depending on type of surgery undergone. Because the etiology of chronic pain is grounded in the bio‐psychosocial model, physical, psychological, and social factors are implicated in the development of CPSP. Biomedical factors such as pre‐operative pain, severe acute post‐operative pain, modes of anesthesia, and surgical approaches have been extensively examined, therefore this systematic review focuses on psychosocial elements. A systematic search was performed using the PubMed, PsychINFO, Embase, and Cochrane Databases. Fifty relevant publications were selected from this search, in which psychosocial predictors for and correlates to CPSP were identified. The level of evidence was assessed for each study, and corresponding score points were awarded for ease of comparison. The grade of association with CPSP for each predictor/correlate was then determined. Depression, psychological vulnerability, stress, and late return to work showed likely correlation with CPSP (grade of association=1). Other factors were determined to have either unlikely (grade of association=3) or inconclusive (grade of association=2) correlations. In addition, results were examined in light of the type of surgery undergone. This review is intended as a first step to develop an instrument for identifying patients at high risk for CPSP, to optimize clinical pain management.     

The effectiveness of non-pharmacological interventions in older adults with depressive disorders: A systematic review

BackgroundIt is widely acknowledged that mental health disorders are common in older adults and that depression is one of the most serious threats to the mental health of older adults. Although best practice guidelines point out that moderate to severe depression should be approached with pharmacotherapy together with complementary therapies, the use of antidepressant drugs in older adults has various disadvantages, such as long response time, side effects, potential risk of dependency and tolerance, poor compliance rates and high probability of drug interactions. In addition, qualitative studies of depressed people with a chronic illness have indicated that both patients and healthcare professionals prefer a psychosocial treatment for depression over a pharmacological one.ObjectiveThis review aimed to identify and synthesize the best available evidence related to the effectiveness of non-pharmacological interventions for older adults with depressive disorders.DesignSystematic review of studies with any experimental design considering non-pharmacological interventions for older adults with depressive disorders.Data sourcesAn initial search of MEDLINE and CINAHL was undertaken, followed by a second search for published and unpublished studies, from January 2000 to March 2012, of major healthcare-related electronic databases. Studies in English, Spanish and Portuguese were included in the review.Review methodsThis review considered studies that included adult patients, aged over 65 years with any type of depressive disorder, regardless of comorbidities and any previous treatments, but excluded those with manic or psychotic episodes/symptoms. All studies that met the inclusion criteria were assessed for methodological quality by two independent reviewers using a standardized critical appraisal checklist for randomized and quasi-randomized controlled studies from the Joanna Briggs Institute. Data extraction was also conducted by two independent reviewers based on the Joanna Briggs Institute data extraction form for experimental studies.ResultsTwenty-three studies met the inclusion criteria. Of those, seventeen were excluded after critical appraisal of methodological quality and six were included in this review. These studies included 520 participants and described cognitive behavior therapy, competitive memory training, reminiscence group therapy, problem-adaptation therapy, and problem-solving therapy in home care. Evidence suggests that all these interventions reduce depressive symptoms.ConclusionsAccording to evidence, non-pharmacological interventions had positive effects on improving patients’ depression and may be useful in practice. However, due to the diversity of interventions and the low number of studies per intervention included in this systematic review, evidence is not strong enough to produce a best practice guideline.