Conservative treatment for chronic coccydynia: a 36-month prospective observational study of 115 patients

Abstract

Purpose

To describe long-term outcomes of conservative treatment for chronic coccydynia.

Methods

We conducted a 36-month prospective observational study. Adults with chronic coccydynia (> 2 months) were included. The first-line treatment was coccygeal corticosteroid injection. The second-line treatment was either manual therapy or coccygectomy. The primary endpoint was the mean variation from baseline of coccydynia intensity at 6 and 36 months, using a numeric rating scale (0, no pain; 10, maximal pain). Evolution was considered unfavorable when coccydynia intensity was > 3 of 10 points at 36 months or coccygectomy had been performed. We carried out bivariate and multivariate analyses to identify variables associated with an unfavorable evolution.

Results

We included 115 participants. Mean (SD) age was 43.5 (12.3) years, duration of coccydynia 18.4 (21.6) months and coccydynia intensity 6.5 (2.0) of 10 points. Mean variations for coccydynia intensity were − 1.5 (3.0) at 6 months and − 2.8 (3.2) at 36 months. At 36 months, 59/115 (51%) participants had an unfavorable evolution. In bivariate analysis, posterior coccyx dislocations were numerically more frequent in participants with an unfavorable evolution compared to others (29/59 (48%) versus 17/56 (30%), p = 0.057). In multivariate analysis, longer duration of coccydynia was associated with an unfavorable evolution (OR = 1.04, 95% CI from 1.01 to 1.07, p = 0.023).

Conclusion

In adults with chronic coccydynia receiving conservative treatment, symptoms decrease overtime, but significantly persist at 36 months in more than half of them. For patients with posterior coccyx dislocation, coccygectomy may be considered rapidly.

Appendices

Appendix 1 Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) Statement

	Item No	Recommendation	Page No
Title and abstract	1	(a) Indicate the study’s design with a commonly used term in the title or the abstract	1
		(b) Provide in the abstract an informative and balanced summary of what was done and what was found	3
Introduction
Background/rationale	2	Explain the scientific background and rationale for the investigation being reported	4
Objectives	3	State specific objectives, including any prespecified hypotheses	4
Methods
Study design	4	Present key elements of study design early in the paper	4
Setting	5	Describe the setting, locations, and relevant dates, including periods of recruitment, exposure, follow-up, and data collection	4
Participants	6	(a) Cohort study—Give the eligibility criteria, and the sources and methods of selection of participants. Describe methods of follow-up Case–control study—Give the eligibility criteria, and the sources and methods of case ascertainment and control selection. Give the rationale for the choice of cases and controls Cross-sectional study—Give the eligibility criteria, and the sources and methods of selection of participants	4, 5
		(b) Cohort study—For matched studies, give matching criteria and number of exposed and unexposed Case–control study—For matched studies, give matching criteria and the number of controls per case	NA
Variables	7	Clearly define all outcomes, exposures, predictors, potential confounders, and effect modifiers. Give diagnostic criteria, if applicable	5, 6
Data sources/measurement	8*	For each variable of interest, give sources of data and details of methods of assessment (measurement). Describe comparability of assessment methods if there is more than one group	5–6
Bias	9	Describe any efforts to address potential sources of bias	NA
Study size	10	Explain how the study size was arrived at	NA
Quantitative variables	11	Explain how quantitative variables were handled in the analyses. If applicable, describe which groupings were chosen and why	6
Statistical methods	12	(a) Describe all statistical methods, including those used to control for confounding	6
		(b) Describe any methods used to examine subgroups and interactions	NA
		(c) Explain how missing data were addressed	NA
		(d) Cohort study—If applicable, explain how loss to follow-up was addressed Case–control study—If applicable, explain how matching of cases and controls was addressed Cross-sectional study—If applicable, describe analytical methods taking account of sampling strategy	NA
		(e) Describe any sensitivity analyses	NA
Participants	13*	(a) Report numbers of individuals at each stage of study—eg numbers potentially eligible, examined for eligibility, confirmed eligible, included in the study, completing follow-up, and analysed	6, Appendix 4
		(b) Give reasons for non-participation at each stage	6, Appendix 4
		(c) Consider use of a flow diagram	6, Appendix 4
Descriptive data	14*	(a) Give characteristics of study participants (eg demographic, clinical, social) and information on exposures and potential confounders	6, Table 1
		(b) Indicate number of participants with missing data for each variable of interest	Tables 1, 2 and 3
		(c) Cohort study—Summarise follow-up time (eg, average and total amount)	NA
Outcome data	15*	Cohort study—Report numbers of outcome events or summary measures over time	Table 2
		Case–control study—Report numbers in each exposure category, or summary measures of exposure	NA
		Cross-sectional study—Report numbers of outcome events or summary measures	NA
Main results	16	(a) Give unadjusted estimates and, if applicable, confounder-adjusted estimates and their precision (eg, 95% confidence interval). Make clear which confounders were adjusted for and why they were included	Table 2
		(b) Report category boundaries when continuous variables were categorized	NA
		(c) If relevant, consider translating estimates of relative risk into absolute risk for a meaningful time period	NA
Other analyses	17	Report other analyses done—e.g. analyses of subgroups and interactions, and sensitivity analyses	NA
Key results	18	Summarise key results with reference to study objectives	8
Limitations	19	Discuss limitations of the study, taking into account sources of potential bias or imprecision. Discuss both direction and magnitude of any potential bias	8, 9
Interpretation	20	Give a cautious overall interpretation of results considering objectives, limitations, multiplicity of analyses, results from similar studies, and other relevant evidence	8, 9, 10
Generalisability	21	Discuss the generalisability (external validity) of the study results	8, 9
Other information
Funding	22	Give the source of funding and the role of the funders for the present study and, if applicable, for the original study on which the present article is based	13

Appendix 2 Paris self-administered questionnaire. Score ranging from 0 (no symptoms) to 10 (maximal symptoms)

Circle the number which best describes your response. To ensure that your questionnaire will count, please answer all 6 questions.

Appendix 3 Modified Dallas self-administered questionnaire. Score ranging from 0 (no symptoms) to 30 (maximal symptoms)

For each question, tick the answer that best suits you.

1) Social activity. How much does your pain interfere with your social life (dancing, games and entertainment, meals or parties with friends, going out, etc.)?

• Not at all (0)

• A little (1)

• Moderately (2)

• A lot (3)

2) Professional activities. How much does your pain interfere with your work?

• Not at all (0)

• A little (1)

• Moderately (2)

• A lot (3)

3) Self-control. How well are you in control of your emotional reactions?

• Totally (0)

• Often (1)

• I'm having trouble (2)

• I can't do it (3)

4) Anxiety/morale. How well do you feel you are dealing with what is required of you?

• Totally (0)

• Often (1)

• I'm having trouble (2)

• I can't do it (3)

5) Worry. How worried are you about your tailbone pain?

• Not at all (0)

• A little (1)

• Moderately (2)

• A lot (3)

6) Stress. How stressed do you feel you are about your tailbone pain?

• Not at all (0)

• A little (1)

• Moderately (2)

• A lot (3)

7) Depression. How depressed have you been since the pain?

• Not at all (0)

• A little (1)

• Moderately (2)

• A lot (3)

8) Relationships with others. How much do you think your pain has changed your relationship with others?

• Not at all (0)

• A little (1)

• Moderately (2)

• A lot (3)

9) Support from others. How much support do you need from others since your pain (housekeeping, meal preparation, etc.)?

• Not at all (0)

• A little (1)

• Moderately (2)

• A lot (3)

10) Adverse reactions of relatives. How do you feel that your pain causes irritation, annoyance, anger towards you in those around you?

• Not at all (0)

• A little (1)

• Moderately (2)

• A lot (3)

Appendix 4 Flow diagram