The Risk of Bias and Sample Size of Trials of Spinal Manipulative Therapy for Low Back and Neck Pain: Analysis and Recommendations

Objective

The purpose of this study was to evaluate changes in methodological quality and sample size in randomized controlled trials (RCTs) of spinal manipulative therapy (SMT) for neck and low back pain over a specified period. A secondary purpose was to make recommendations for improvement for future SMT trials based upon our findings.

Methods

Randomized controlled trials that examined the effect of SMT in adults with neck and/or low back pain and reported at least 1 patient-reported outcome measure were included. Studies were identified from recent Cochrane reviews of SMT, and an update of the literature was conducted (March 2013). Risk of bias was assessed using the 12-item criteria recommended by the Cochrane Back Review Group. In addition, sample size was examined. The relationship between the overall risk of bias and sample size over time was evaluated using regression analyses, and RCTs were grouped into periods (epochs) of approximately 5 years.

Results

In total, 105 RCTs were included, of which 41 (39%) were considered to have a low risk of bias. There is significant improvement in the mean risk of bias over time (P < .05), which is the most profound for items related to selection bias and, to a lesser extent, attrition and selective outcome reporting bias. Furthermore, although there is no significant increase in sample size over time (overall P = .8), the proportion of studies that performed an a priori sample size calculation is increasing statistically (odds ratio, 2.1; confidence interval, 1.5-3.0). Sensitivity analyses suggest no appreciable difference between studies for neck or low back pain for risk of bias or sample size.

Conclusion

Methodological quality of RCTs of SMT for neck and low back pain is improving, whereas overall sample size has shown only small and nonsignificant increases. There is an increasing trend among studies to conduct sample size calculations, which relate to statistical power. Based upon these findings, 7 areas of improvement for future SMT trials are suggested.     

Barriers to healthcare as reported by rural and urban interprofessional providers

Summary

The research literature is replete with reports of barriers to care perceived by rural patients seeking healthcare. Less often reported are barriers perceived by the rural healthcare providers themselves. The current study is an extensive survey of over 1,500 healthcare providers randomly selected from two US states with large rural populations, Alaska and New Mexico. Barriers consistently identified across rural and urban regions by all healthcare professionals were Patient Complexity, Resource Limitations, Service Access, Training Constraints, and Patient Avoidance of Care. Findings confirmed that rural areas, however, struggle more with healthcare barriers than urban and small urban areas, especially as related to Resource Limitations, Confidentiality Limitations, Overlapping Roles, Provider Travel, Service Access, and Training Constraints. Almost consistently, the smaller a provider's practice community, the greater the reports of barriers, with the most severe barriers reported in small rural communities.     

Symptoms, airway physiology and histology of workers exposed to medium-density fiber board.

Medium-density fiber (MDF) board was recently introduced in the furniture industry. In this pilot study health complaints, physiology, and histology of the upper airways were evaluated for two groups of workers, one handling MDF board for at least one-third of their work week (MDF group) and another handling traditional fiber board. Civil servants served as a reference group. The frequency of health complaints concerning the airways was higher, the sense of smell was poorer, and the frequency of nasal obstruction measured with rhinomanometry was higher for the MDF group, while mucociliary activity was lower in the group handling traditional board. In both groups forced vital capacity was low when compared with expected values. Histological specimens from the middle turbinate of the nose showed, in a few cases, nasal epithelial dysplasia in the traditional board group, but histological changes in terms of scoring did not differ significantly between the groups.     

Rapid identification of pathogenic yeast isolates by real-time PCR and two-dimensional melting-point analysis

There is a need in the clinical microbiological laboratory for rapid and reliable methods for the universal identification of fungal pathogens. Two different regions of the rDNA gene complex, the highly polymorphic ITS1 and ITS2, were amplified using primers targeting conserved regions of the 18S, 5.8S and 28S genes. After melting-point analysis of the amplified products, the T_m of the two PCR-products were plotted into a spot diagram where all the 14 tested, clinically relevant yeasts separated with good resolution. Real-time amplification of two separate genes, melting-point analysis and two-dimensional plotting of T_m data can be used as a broad-range method for the identification of clinical isolates of pathogenic yeast such as Candida and Cryptococcus spp.     

Vaginal construction with skin grafts and vacuum-assisted closure.

Probably the most common method of constructing a vagina in patients with the Mayer-Rokitansky-Küster syndrome is the technique popularised by McIndoe and Banister in 1938. A cavity is created between the rectum and urethra-bladder complex and is lined with split-thickness skin grafts. One of the disadvantages of using split-thickness skin grafts is the incidence of late contraction of the neovagina. To avoid this problem full-thickness skin grafts have been used, but their take is less reliable. A new technique to improve the take of skin grafts is the VAC-system (vacuum assisted closure, KCI) which has proved to be particularly valuable in grafting difficult anatomical sites. We have used the VAC-system in the construction of a vagina in one case with split-thickness skin grafts and in two cases with full-thickness skin grafts. In all three cases the take was excellent with little discomfort for the patients. It was not necessary to stent the neovagina in the postoperative period and coitus was possible within a month of operation.     

Paradoxical sphincter reaction is influenced by rectal filling volume

PURPOSE: Paradoxical sphincter reaction is frequently found in constipated patients but sometimes also in incontinent patients and in asymptomatic subjects. Its significance in defecation disorders has, therefore, been debated. The aim of the present study was to investigate whether paradoxical sphincter reaction is influenced by rectal filling volume. PATIENTS AND METHODS: Eighteen patients with defecation disorders and paradoxical sphincter reaction shown by electromyography were reinvestigated with an extended electromyographic investigation while in the lying position and while in the sitting position, with 50-ml, 100-ml, and 150-ml water-filled rectal balloons. RESULTS: All 18 patients showing paradoxical sphincter reaction in the first investigation also showed the reaction at the second investigation in the lying position with a 0-ml volume of rectal contents. In the sitting position, with a volume of 150 ml of rectal contents, the increase in electromyographic activity disappeared in seven patients (39 percent) and no longer showed paradoxical sphincter reaction. Electromyography showed decreased activity in one patient and unchanged activity in six patients during straining. A closing reflex was seen after completed straining in all of these seven patients. CONCLUSIONS: The present study demonstrates that paradoxical sphincter reaction diagnosed by electromyography is influenced by the rectal filling volume and might diminish when the rectum is filled with contents. The conventional electrophysiologic technique in the diagnosis of paradoxical sphincter reaction might, therefore, overdiagnose this condition.     

Clodronate reduces plate osteopenia in the rabbit

An osteosynthesis with a four-hole AO/ASIF-DCP plate was performed on the right tibia of 40 rabbits. Clodronate (50 mg/kg s.c.) was given once a week, resulting in a mean bone concentration of 509 µg/g in 2 hours. Plate fixation caused a decrease in mean net cross-sectional area of compact cortical bone of 17 percent at 9 weeks and 46 percent at 18 weeks. This resulted from bone resorption in bone under the plate, from pronounced cavitation in the plated bone (about 5 percent of cortical bone area at 9 weeks and 15 percent at 18 weeks), and from the fact that the medullary space was increased by 15 percent at 18 weeks. The total cross-sectional area of the diaphysis was increased by 31 percent at 9 weeks and by 17 percent at 18 weeks.

Clodronate treatment reduced cortical porosity to about half of the mean values in the placebo group. Clodronate increased both the calcium content in the retained bone and the cross-sectional area of compact cortical bone, but induced only an insignificant increase in the area of periosteal new bone. Clodronate treatment seems not to be contraindicated in conjunction with rigid osteosynthesis, and may even slow down the osteopenic response occurring under the rigid plate.     

Results of rectocele repair

PURPOSE: This study was designed to evaluate the results of rectocele repair and parameters that might be useful in selecting patients for this operation. METHODS: Twentyfive patients with symptom-giving rectoceles were prospectively evaluated with a standardized questionnaire, physical examination, defecography, colon transit studies, anorectal manometry, and electrophysiology. Patients underwent posterior colporrhaphy and perineorrhaphy. They were followed postoperatively (mean, 1.0 year) with the same questionnaire, physical examination, defecography, anorectal manometry, and electrophysiology. RESULTS: Constipation had improved postoperatively in 21 of 24 constipated patients (88 percent). At postoperative follow-up 13 patients (52 percent) had no constipation symptoms, 8 (32 percent) had occasional symptoms, and 4 (16 percent) had symptoms more than once per week. Four patients with rectocele at preoperative defecography, but not at physical examination, had favorable outcomes following surgery. The majority of patients not using vaginal digitalization preoperatively had improved with respect to constipation. All patients with pathologic transit studies had various degrees of constipation postoperatively. Constipation was not improved in two of five patients with preoperative paradoxic sphincter reaction. CONCLUSIONS: Rectocele is one cause of constipation that can be treated with good results. Preoperative use of vaginal digitalization is not mandatory for a good postoperative result. Defecography is an important complement to physical examination. Patients with pathologic transit study might have a less favorable outcome of rectocele repair with respect to constipation. More studies about the significance of paradoxic sphincter reaction in these patients are indicated.Poster presentation at the XVth Biennial Congress of the International Society of University Colon and Rectal Surgeons, Singapore, July 2 to 6, 1994.     

Replacement of the Femoral Head by Ceramic Endoprosthesis: An Experimental Study on Rabbits

In 31 rabbits the femoral head was replaced by a ceramic endoprosthesis. For 11 of the experimental animals the endoprostheses were made by the Arabia China Factory in Helsinki, and for 20 by Staatliche Porzellan Manufaktur in Berlin. The operation was performed under fully sterile conditions and the follow-up time was between 6 and 34 weeks. The hip joint was examined clinically, roentgenologically, macroscopically and histologically.

The bending tolerance of the ceramic endoprosthesis was not adequate. Mechanical loosening of the proximal part of the prosthesis occurred in 68 per cent and was combined with fracture of the prosthetic stem. This created a pseudarthrosis-like reaction in the acetabular area and limited the movement of the hip joint. The distal fragment of the stem was always surrounded by a thin layer of dense bone. In the nonfractured cases (32 per cent), however, the reaction was only moderate and the movement of the hip joint was well preserved. The tissue reactions to the ceramic material were slight, but the great number of secondary reactions following stem fractures make the use of the ceramic endoprosthesis questionable in experiments with rabbits.