Hypothesis / aims of study
Background: Non-cyclical chronic pelvic pain (CPP) does not present exclusively with symptoms of dyspareunia, dyschezia or dysuria but can present with additional symptoms such as suprapubic and lower abdominal pain, and painful pelvic musculatures (1). The pain can worsen after pelvic floor related activities such as coitus or voiding . Myofascial pelvic pain (MFPP) is caused by the presence of myofascial trigger points (MTrPs) in the pelvic muscles and the pelvic floor muscles (PFM) and it can be the primary mediator for non-cyclical CPP (1).
This study analysed trans-perineal trigger point dry needling (TrDN) combined with manual therapy for the PFM and compared it with manual therapy for non-cyclical chronic pelvic pain.
Primary objective- Number of treatments required within the allocated ten treatments to effect improvement. The session where the participant ceased treatment due to resolution was noted as the end point. To evaluate the decrease in pain, the 0-10 Numeric Pain Rating Scale (NPRS) was analysed at baseline, the tenth treatment or earlier as per resolution.
Secondary objective- Dyspareunia, bladder and musculoskeletal pain variables which were evaluated with the Female Sexual Function Index questionnaire (FSFI) and an abbreviated version of the International Pelvic Pain Questionnaire (IPPQ) pre-treatment and after the final treatment.
Study design, materials and methods
Since this is the first study to analyse TrDN treatment of the PFM, the power in these studies (2,3) were compared and it was estimated that in order to determine a p< 0.05, with 80% power, α=0.05, β=0.2, SD=1 for the outcome in the population and a mean change of 0.634, a total of 81 participants were required. Since a similar study analysing manual interventions for pelvic floor pain was not statistically significant (3), a minimal clinically important difference (MCID) was considered to be of practical significance. In chronic pain management, a 50% decrease in pain from baseline is rated as significant improvement, while a 30% decrease is rated as a meaningful improvement.
The gynaecologists from two clinics referred 142 patients and 102 participants confirmed interest. Their names were allocated into opaque envelopes marked as group A (manual therapy) and group B (TrDN with manual therapy) by administrative staff unrelated to the trial. Group A participants (n=39) were allocated among three Senior Physiotherapists in Women's Health including the researcher and group B (n=40) were allocated only to the researcher.
Standardisation of treatment was only required for group A as three clinicians provided the treatment. All the questionnaires were filled by the individuals prior to their treatment and stored at a secured locked storage at the hospital. On trial completion, the data was analysed for correct input by three clinicians unrelated to the trial. Statistical analysis was carried out using the SPSS software version 24.
Of the 102 consented participants, 23 dropped-out after allocation and 79 participants completed the trial.
Dyspareunia was reported by 92% of the participants with a higher mean standard deviation (SD) of 7.15(2.84) followed by muscle pain in 98% of the participants with mean (SD) of 4.15(3.7). The mean (SD) pain score for mixed cyclical menstruation-related symptoms was a low 4.68(3.85) and bladder pain was 3.6(3.5).
Kaplan-Meier survival curve analysis was used to determine the statistically significant difference between the endpoint. The median [95% CI] for the number of treatments required by group A was 8[6.951, 9.049] and for group B was 5[4.393, 5.607]. Group B required a median of five treatments with statistically significant (p< 0.001) endpoint.
NPRS: Within-group analysis showed a statistically significant decrease.
Group A: t(38)=12.8, p< 0.001 with a 95% CI [4.12,5.7]
Group B: t(39)=29.3, p< 0.001 with a 95% CI [6.98,8.01]
Group A: Pre-treatment median (IQR) 8(9.0-7.0), post-treatment median (IQR) 2(4.0-1.0)
Group B: Pre-treatment median (IQR) 8(9.0-7.0), post-treatment median (IQR) 1(1.0-0.00)
Between-group analysis was statistically significant for group B with t(77)=5.14, p< 0.001 and a 95% CI [1.3, 2.9].
Group A: Pre-treatment below normal FSFI score reported by 84% (32/38), normal FSFI score reported by 16% (6/38). Post-treatment normal FSFI score reported by 44% (16/36)
Group B: Pre-treatment below normal FSFI score reported by 100% (37/37). Post-treatment normal FSFI score reported by 58% (21/36). A univariate analysis showed statistical significance for group B (F[1,71]=4.5, p=0.036).
Seventeen 0-10 Likert scale variables were grouped as : dyspareunia, musculoskeletal pain, menstrual-cycle related pain and bladder pain. All dyspareunia variables, some mixed-cyclical menstrual pain variables and all the musculoskeletal pain variables were statistically significant for group B. No between-group significance were seen for bladder pain variables.
Interpretation of results
Group B required a median of five treatments. Three participants in group A with higher post-treatment scores than their pre-treatment score after ten treatments were considered as outliers and they were transferred into group B to review variance at the endpoint. The difference was reduced but still significant with p<0.004. Group A endpoint median [95% CI] reduced to 7[6.62, 8.0] and group B endpoint was 5[4.7, 5.8].
The cumulative final NPRS median (IQR) was 1(3.0-0.00), showing clinical efficacy for the individual treatments in the reduction in pain. The Independent Samples T-test was used for between-group analysis which showed group B to have a statistically significant final NPRS reduction of p<0.001 with a 95% CI [1.3, 2.9] and a median (IQR) of 1(1.0-0.00) compared to group A median (IQR) of 2(4.0-1.0). Due to the three influential outliers in group A, an univariate General Linear Model (GLM) analysis was used to determine if the mean pain level at the endpoint (final NPRS) differed between the groups. After the adjustment, the final NPRS median (IQR) for group A was 2(3.75-1.00) while group B was 1(1.00-0.00) with statistical significance for the TrDN group of p<0.001, [95% CI] [1.01, 2.14].
As removing the outliers did not influence change, the remaining analysis was done without adjustment.
Seventy nine participants completed the pre-treatment FSFI questionnaire with only six scoring a normal score of =/>26.6 in group A. In group A, 32 scored <26.6 and one reported as not sexually active (NSA) and in group B 37 scored <26.6 and three were NSA. In addition to the six participants with a normal pre-treatment total score in group A, a further 10 (28%, 10/36) recorded =/>26.6 post-treatment score. Post-treatment, the six participants of group A with the normal pre-treatment FSFI scores did not deteriorate below their baseline score. A total number to 44% (16/36) in group A and 58% (21/36) in group B achieved a normal FSFI score, showing a 17% improvement for group B.
The IPPQ dyspareunia outcomes were similar to the FSFI outcomes as given in figure 1.
Although the demographic distribution between both groups are similar, statistically significant outcomes were demarcated for group B for pain, dyspareunia and musculoskeletal variables, achieved with fewer treatments. Post-treatment, the with-in group significance for all variables were over the 50% minimal clinically important difference, indicating the relevance of Physiotherapy for non-cyclical CPP.