Discussion:
Main findings:
The Cumberledge enquiry has highlighted a lack of long-term outcomes for the mid-urethral tape procedures (MUS)1. As recommended in this inquiry, as well as the ICI guidelines10, patient perception of outcomes using patient reported outcome measures (PROM’s) were used to evaluate long terms outcomes 12 years after TVT and TOT procedures. PROMS’s used in this follow-up as well as the original study, reduces the bias of health care personnel’s impression of outcome. The 12year results show that TVT is superior to TOT for cure of stress urinary incontinence in the long-term and that the two procedures are comparable in terms of complications. However, there was a decline in success and satisfaction with time, as seen with other surgeries for SUI such as colposuspension.
For the assessment of success, the primary study defined ‘cure’ as ‘never’ on the ICIQ FLUTS questionnaire Q8a: “does urine leak when you are physically active, exert yourself, cough or sneeze?”7. The same was used in this long-term follow-up study. This might be regarded as a strict definition. For example, there was a large proportion of women in this study who reported SUI ‘occasionally’ only i.e. 35% TVT and 36% TOT. This level of incontinence was not regarded as bothersome. Despite the lower subjective success rate, both the TVT and TOT produced significant improvement in symptoms according to the PGI-I for the majority of participants.
Objective and subjective cure rates for the MUS differ depending on the length of follow up, criteria used for definition of cure and the instruments used for assessing cure e.g. questionnaires, pad tests or urodynamic findings. The long term (>5 years) efficacy and safety of the MUS procedures are summarised in a systematic review by Maggiore and colleagues11. They report an objective cure rate for the TVT and TOT procedures of 57.2% and 68.8% respectively11. Nilsson and colleagues reported a 90% objective continence rate following retropubic tape procedure based on cough test, and 87% continence rate based on PGI-I at 17 years follow-up12. Since then further reports on long-term efficacy on all types of MUS have been published with cure of SUI ranging from 65% to 97%13,14,15,16.
Interpretation:
These differences in outcomes can also be attributed to the patient population, with studies with higher cure rates excluding patients with mixed incontinence. Our study includes patients with SUI-predominant mixed incontinence. It is therefore recommended that all studies use standardised outcome measures which will enable systematic reviews and meta-analyses to inform clinical practice and patient counselling e.g. as recommended by ICI10.
The mid-urethral sling procedure was placed under high vigilance restriction by the FDA in 2011 and the UK NHS Improvement (NHS England) in 2018. This was secondary to reports of pain and complications in some women following tape insertion and highlighted in the Cumberledge report1. This led to public campaigns and legal action to raise awareness along with subsequent media reports17. The true extent of the problem is unclear thus this study aimed to assess the proportion of women who reported pain and its severity long-term. The results showed that the majority of women were pain-free. For those who reported moderate pain, it did not have a significant impact on quality of life and surgical intervention was required for a minority. For the 6% of women with severe pain, their quality of life was diminished. It is therefore important to emphasise the need for appropriate pre-operative counselling about this risk. Early surgical intervention for complication management is recommended to achieve symptom resolution18.
An attempt to understand why women have a different response to the same treatment is important. Greater attention to patient selection, preoperative assessment and surgical technique might be critical to optimizing outcomes from the procedures19.
Our study respondents are 12 years older and it could be argued that the urinary urgency and UUI reported are a result of ageing rather than the long-term effects of surgery20. However, comparison of the baseline prevalence with the 12year follow-up data confirmed a decrease in the number of participants reporting these symptoms. The population recruited to the original trial was comprised of women with mixed incontinence: 93.5% TVT and 97% TOT group had reported any UUI prior to their surgery and 87% TVT and 89% TOT group reported any urinary urgency7. Consequently, though the prevalence of UUI and urinary urgency at 12 years is deemed high, comparison with the baseline prevalence of both symptoms confirms a reduction of these symptoms at 12 years for both the TVT and TOT groups. In addition, urinary urgency and UUI did not represent significant bother for the majority of patients.
Strengths:
A number of studies exist, which analyse the long-term outcomes of MUS. This study represents one of few studies which specifically compares the efficacy and complications between the TVT and TOT procedures in the long term. The study thus provides unique information on the superior efficacy of the TVT procedure in direct comparison to the TOT procedure in a randomised controlled trial setting.
Additionally, we specifically addressed the pain and complications issue presented by the adverse media reports, by using both a numeric rating scale for pain and a free text space for additional comments. This has the advantage of giving the patients a platform to report any issues they have experienced with the tapes. We are confident that the participants report of no complications was accurate, as it is possible that the adverse media reports could result in patient anxiety and self-referral for assessment. Thus, the inclusion of a free text box for added comments represents a strength of the study.
Limitations:
Statistical analysis could not be performed to compare pain scores between the TVT and TOT procedures because the majority of respondents (>80% in both groups) reported no pain. However, the trend for no difference between the groups is apparent.
Additionally, analysis of all returned questionnaires at 12 years was limited as there was incomplete information from 11 participants from the 1year study. Consequently, despite receiving 121 returned questionnaires, paired ICIQ-FLUTS analysis between long- and short-term outcomes could only be performed on 110 participants, reducing the data available for analysis from 70% to 64%.
Due to the UK research governance regulations, General Practitioner records could not be accessed to identify other issues which were managed in the community. Likewise, the hospital records of those patients who had not given consent for participation in this follow- up trial could not be accessed. This represents the main limitation of the study. The response rate of 70% could have been improved if further reminders had been sent, but only one was allowed by research ethics.