An interview with Professor Arantxa Muñoz Duyos, Colorectal Surgeon, Clinical Head of Surgery at Hospital Universitari Mútuterrassa in Barcelona.

Professor Arantxa Muñoz Duyos (Prof AMD) is an expert in proctology and pelvic floor disorders at a referral centre for complex cases, as well as leading national educational courses in faecal incontinence and Sacral Neuromodulation since 2004.

MC: Firstly, let me thank you for agreeing to participate in this interview! It is a pleasure to interview you and learn more about your view on Sacral Neuromodulation. Your centre is a reference on Sacral Neuromodulation, not only in Spain but also all over Europe. Please tell us the story of SNS at your centre. When did you start with Sacral Neuromodulation? How many patients have been treated at your centre so far?

Prof AMD: We were the first centre to introduce Sacral Neuromodulation in Spain in 1996, when we participated in the first European study which was published in the Lancet in 2004. Dr Josep Rius, one of my teachers, did a fellowship at the Cleveland Clinic Florida and he assisted to a meeting where Medtronic presented this therapy for the first time. He asked the company to contact us if they carried out a study in Europe and this was the beginning of a successful history in our centre. At that time, I was a surgical resident and was in charge of collecting data on patients’ outcomes and quality of life after Sacral Neuromodulation. I was really surprised to find out about young ladies suffering from faecal incontinence who improved after the treatment. Later on, I did my Ph.D. on sacral neuromodulation and together with Dr Albert Navarro, my other teacher, we started doing courses about this therapy, initially locally and then all over Spain. Nowadays, we are a referral centre for complex proctology and pelvic floor disorders. We have done more than 350 sacral neuromodulation procedures and have implanted 236 patients.

MC: ESCP Guidelines point us to the best patients to select for this therapy. However, as you mentioned in a recent paper, we have guidelines from different societies, and there seems to be no global agreement. How do you select the ideal patient for sacral neuromodulation in your clinical practice? In fact, what are the clinical indications for Sacral Neuromodulation?

Prof AMD: Even though there is no consensus about what to do in different clinical scenarios of faecal incontinence, but there is quite an agreement that sacral neuromodulation is very helpful in different types of faecal incontinence. In many cases it is in the second step of the algorithm after conservative treatment and rehabilitation. In our courses, we always advise our students to start with cases of multifactorial faecal incontinence. They are usually women in their sixties who experience severe incontinence due to the sum of many factors that damage the pelvic floor over the years. In our experience, this is the group of patients with the best response to this treatment. However, patients with neurological faecal incontinence, LARS patients, patients after radiotherapy, and those with congenital faecal incontinence with some anal canal structure left, can also be good responders to Sacral Neuromodulation. Patients with a long-term external anal sphincter injury can also be good candidates for this treatment, before sphincteroplasty. Finally, patients who do not improve after sphincteroplasty can also benefit from it. There is not much consensus about the predictive factors of this therapy, but the test phase is an efficient predictor of success.

MC: Concerning the surgical technique. Can you briefly explain to us how you do it? (Is it an ambulatory procedure? What kind of anaesthesia is used? How do you identify and choose the nerve root?)

Prof AMD: We perform the technique under local anaesthesia and sedation, as an outpatient procedure. We do it in the operating room because it is more comfortable for patients when sedation is used, and because we always use fluoroscopy to check the correct location of the lead. Antibiotic prophylaxis is very important not to administer postoperative antibiotics that could alter the defecatory function (i.e. causing diarrhoea) and interfere with the test phase results. We test two to four roots, sometimes the two S3 and the two S4, and we choose the root with the best motor response at lower amplitude stimulation, in a minimum of three poles of the four poles of the tined lead. We use some landmarks to achieve a good location of the lead, and we check it with fluoroscopic imaging. It is an easy and reproducible procedure. We are part of the European Expert Group in Sacral Neuromodulation that standardize the technique which was published on Neuromodulation in 20171.

I would like to explain that there is a new monopolar electrode for the test phase which can be inserted in a quite easy reproducible technique in the outpatient clinic. On the other hand, results about one stage implant procedure will be published soon. This means that we will be able to implant the lead and the impulse generator in selected patients with a good intraoperative response in one surgical procedure (without a phase test) with a high probability of success.

MC: Let’s discuss surgical complications, success rates, and follow-up. What are the most common short and long-term complications you face? Can you give us an overview of the success rate of this technique? How do you usually follow up on these patients?

Prof AMD: We follow our patients twice or three times during the phase test to optimize this important phase and avoid false positive or false negative cases. The success rate of this technique once patients are implanted is around 70-80%, depending on the type of faecal incontinence and these results are maintained over time. However, patients have many mild issues and need to be followed closely. Once implanted, we follow them up two weeks after surgery to rule out surgical complications, and afterwards visits are scheduled at one and six months after surgery, and then yearly. Intraoperative surgical complications are very uncommon. The most severe case published in the literature is presacral bleeding in patients treated with anticoagulant treatment. During the follow up, the most severe complication is the device infection that can be reduced with the right antibiotic prophylaxis and being very strict with the intraoperative measures. We also advice our students to cut the percutaneous extension used in the test phase, in the outpatient clinic, once we have decided if the patient is a candidate to be implanted, in order to allow the external opening in the skin to be closed before going to the impulse generator implant. Common issues are pain related to the therapy and the loss of efficacy requiring electrical reprogramming. The main reasons to explant patients during the follow-up are Infection and a maintained loss of efficacy. Specialized nurses are very important in a unit doing sacral neuromodulation, as they will work managing these issues considering the increasing volume of patients in clinics.

MC: Support groups of patients with faecal incontinence do exist in Spain. Do you think this is, indeed in such a particular disease? How do these groups contribute to the surgeon vs patient relationship? Are these groups usually involved in research?

Prof AMD: In our centre, we identified the need of involving patients to give voice to the so-called silent syndrome. Consequently, we created a Patient’s Association for Faecal Incontinence in 2012. After many meetings developing the definitive idea, ASIA (Asociación en Incontinencia Anal) was created in 2013 and nowadays, they have spread all over Spain. They help patients improving the opportunity to reach all kind of treatments. They are well known by Scientific Societies and are doing a very good work.

MC: That brings us to the end of this interview! Thank you for sharing your insight and expertise with us. As for a final question, what advice would you give young Colorectal Surgeons interested in starting this technique in their centre? How can they start to implement this technique?

Prof AMD: I would advise to learn the surgical technique but also the correct way to evaluate patients with faecal incontinence in depth. This disorder is complex and the success of treatments will be closely related to a good patient evaluation. Moreover, as there is no consensus on the different clinical guidelines, it is important to have experts with high volume experience in order to consult them in complex or difficult cases. I would also advise organizing a unit structured to achieve an accurate diagnosis and appropriate follow-up including specialized nurses, and finally connecting patients with other patients or patient associations.

1 Matzel et al. Sacral Neuromodulation: Standardized Electrode Placement Technique. Neuromodulation. 2017

ESCP Affiliates