Sacral Neuromodulation in pediatric gastrointestinal motility disorders: Prospective cohort trial

This prospective cohort trial demonstrates that both invasive sacral neuromodulation and noninvasive enteral neuromodulation are effective and safe treatments for refractory pediatric gastrointestinal motility disorders, showing comparable success rates despite differences in patient severity and invasiveness.

The Gist

Imagine your body's digestive system as a busy highway. Normally, traffic (food and waste) flows smoothly from the stomach to the exit. But for some children, this highway gets jammed, or the traffic lights at the exit (the pelvic floor) get stuck, causing painful backups, accidents (incontinence), and constant traffic jams (constipation).

This happens even when the road itself isn't broken (no blockages or diseases like Crohn's); the problem is just that the electrical signals telling the muscles when to move are out of sync. This is called a "Gastrointestinal Motility Disorder."

When standard treatments like diet changes and laxatives (the "road work" and "traffic police") fail, doctors usually have to consider major surgery, like cutting a section of the highway or building a detour (ostomy).

Diez et al. (2026) asked a big question: Is there a way to fix the traffic lights without cutting the road?

They tested two different ways to send new electrical signals to the nerves in the lower back (the sacrum) to reboot the system. Think of these nerves as the "remote control" for the bathroom muscles.

The Two "Remote Controls" Tested

The study compared two methods to send these signals:

1. The "Invasive" Remote (SNM - Sacral Neuromodulation)

• How it works: This is like installing a permanent, high-tech receiver under the skin. A surgeon places a tiny wire electrode directly onto the nerve root (S3 or S4) and connects it to a small battery pack implanted under the skin.
• The Analogy: Imagine wiring a new, dedicated fiber-optic cable directly into the main switchboard of the house. It's a one-time surgery, but it's permanent and requires a doctor to install it.
• Who got it: 18 children. These kids often had more complex medical histories or severe comorbidities.

2. The "Non-Invasive" Remote (ENM - Enteral Neuromodulation)

• How it works: This is like using a smart patch on the outside of the house. Doctors stick adhesive electrodes on the skin over the lower back and connect them to an external battery pack. The electricity travels through the skin to reach the nerves.
• The Analogy: Instead of wiring the house, you use a powerful remote control that sends signals through the walls. It's not permanent, you can take it off, and there's no surgery.
• Who got it: 30 children. This group generally had fewer severe complications.

What Did They Find?

The researchers followed these kids for a year and asked: "Did the traffic start moving again?"

• The Results were Surprisingly Equal: Both methods worked almost exactly the same!

  • 80% of the kids using the skin patches (ENM) got better.
  • 83% of the kids with the implanted device (SNM) got better.
  • There was no statistical difference in success rates. Both groups saw less pain, fewer accidents, and more regular bathroom trips.

• Safety: Both methods were safe.

  • The "skin patch" group had some minor skin rashes (like a sticker leaving a red mark), which were easily fixed by changing the sticker type.
  • The "implant" group had one infection at the surgery site, which was treated, and a few minor technical glitches (like a wire breaking before the battery was fully installed), but no major disasters.

• The "Real World" Factor:

  • SNM (Implant): Once it's in, it just works. You don't have to remember to put it on. However, it requires surgery and anesthesia.
  • ENM (Patch): It's great because it's not surgery, but it requires discipline. Kids have to wear the device for 8–12 hours a day. Some kids had trouble with the equipment breaking or forgetting to wear it.

The Big Takeaway (The "So What?")

Before this study, if a child had severe constipation that wouldn't go away, the only options were "keep trying laxatives" or "cut the colon."

This study shows there is a middle ground.

• If a child is very sick, has complex medical issues, or can't handle wearing a device all day: The Implant (SNM) might be the better choice because it's always on and works reliably.
• If a child wants to avoid surgery, has a simpler case, or is worried about the risks of an operation: The Skin Patch (ENM) is a fantastic, effective alternative that avoids the knife entirely.

In a Nutshell

Think of this study as proving that you don't always need to rebuild the house to fix a broken door. Sometimes, you can just install a new lock (Implant), and sometimes, you can just use a really good keycard on the outside (Patch). Both open the door, and both let the traffic flow again.

The authors conclude that doctors now have two powerful tools to help children avoid more drastic, irreversible surgeries, offering a "multimodal" (many-ways) approach to fixing the gut's traffic jams.

Technical Summary

Based on the preprint by Diez et al. (2026), here is a detailed technical summary of the study regarding Sacral Neuromodulation (SNM) in pediatric gastrointestinal motility disorders.

1. Problem Statement

Functional gastrointestinal motility disorders (GMD) in children, such as refractory constipation and fecal incontinence, represent complex dysregulations of the brain-gut axis. Current therapeutic approaches are largely symptomatic and often fail in up to one-third of patients, leading to severe complications like irreversible rectal dilatation, chronic pain, and psychosocial distress. When conservative management fails, patients often face irreversible surgical interventions (e.g., colectomies or ostomies).

While Sacral Neuromodulation (SNM) has been successfully repurposed from urology to treat adult fecal incontinence, its application in pediatrics remains limited and controversial due to the invasiveness of implanting electrodes in growing children. Conversely, a non-invasive alternative, Enteral Neuromodulation (ENM), using surface electrodes, has been proposed but lacks robust comparative data against invasive SNM in a prospective pediatric cohort.

2. Methodology

Study Design:

• Type: Prospective interventional cohort trial (single-center, tertiary referral).
• Location: University Hospital Erlangen, Germany.
• Period: January 2019 – December 2024.
• Registration: ClinicalTrials.gov (NCT04713085).
• Participants: 70 eligible patients aged 4–17 years with therapy-refractory GMD (meeting Rome IV and ESPGHAN criteria).
  • Exclusion: Mechanical causes of constipation or inflammatory bowel disease.
  • Allocation: Originally intended as 1:1 randomization. However, due to high parental rejection of invasive surgery, the final cohort was 18 patients in the SNM group and 30 in the ENM group (2:1 ratio).
• Interventions:
  • SNM (Invasive): Two-stage surgical implantation of a tined-lead electrode on sacral roots S3/S4, connected to an implanted pulse generator (Medtronic InterStim™). Stimulation was continuous.
  • ENM (Non-invasive): Application of adhesive surface electrodes over the upper sacrum connected to an external pulse generator. Stimulation was applied for a minimum of 8 hours/day.
• Stimulation Parameters:
  • Frequency: 14 Hz.
  • Pulse Width: 210 µs.
  • Intensity: Individualized based on perianal sensation below pain threshold (Median: 1.0 mA for SNM; 6.0 mA for ENM).
• Outcomes:
  • Primary: Abdominal pain, fecal incontinence, defecation frequency, and stool consistency.
  • Success Definition: Clinically significant improvement (>50%) in at least two of the four primary domains.
  • Secondary: Quality of life (KINDLR), proprioception, safety/adverse events, and patient satisfaction.
  • Follow-up: Assessments at 4, 8, 12 weeks, and 12 months.

3. Key Contributions

• First Prospective Comparison: This study provides the first prospective, head-to-head comparison of invasive SNM and non-invasive ENM specifically in a pediatric population with refractory GMD.
• Validation of Non-Invasive Approach: It demonstrates that ENM achieves clinical efficacy comparable to invasive SNM, offering a viable alternative that avoids anesthesia and surgical risks.
• Patient Stratification: The study identifies distinct patient profiles suitable for each modality, suggesting that while efficacy is similar, the choice of treatment should depend on comorbidity severity and family preference regarding invasiveness.
• Long-term Safety Data: It offers 12-month follow-up data on safety and durability for both modalities in children, a demographic where long-term data is scarce.

4. Results

Demographics & Baseline:

• Completion: 48 patients completed the study (18 SNM, 30 ENM); 31% dropout rate.
• Comorbidities: The SNM group had significantly higher rates of severe comorbidities (45% vs. 3% in ENM; P = .0018), indicating a selection bias where families of severely ill children opted for surgery.

Efficacy:

• Treatment Success: No significant difference in overall response rates.
  • ENM: 80% (24/30)
  • SNM: 83% (15/18)
  • P = 1.00.
• Symptom Improvement: Both groups showed significant improvements in defecation frequency and fecal incontinence. Abdominal pain decreased significantly in both.
• Urinary Incontinence: Only the SNM group showed a significant improvement in urinary incontinence, likely due to more precise stimulation of the S3/S4 roots.
• Proprioception: Multivariable logistic regression indicated that the neuromodulatory approach and comorbidity severity were independent variables for proprioception improvement. Higher comorbidity severity correlated with lower probability of proprioceptive improvement.

Long-term Follow-up (12 Months):

• Overall Response: 75% (36/48) maintained therapeutic response at one year.
• ENM Specifics: 50% of ENM patients were symptom-free at 12 months. However, 17% of initial ENM responders lost efficacy after stopping treatment (as many ENM patients only continued for 12 weeks).
• SNM Specifics: 50% of SNM patients were symptom-free. Three non-responders at 12 weeks remained non-responders at 12 months and were scheduled for device removal.

Safety & Adverse Events:

• Major Complications: None in ENM; one surgical site infection in SNM (requiring device removal and re-implantation).
• Minor Complications:
  • ENM: 27% experienced skin exanthema under electrodes (resolved by changing electrode type/placement).
  • SNM: Minor issues included subcutaneous tingling (resolved by battery management) and one electrode breakage prior to generator implantation.
• Satisfaction: High in both groups (Median 5/7 for ENM, 6/7 for SNM; P = 0.875).

5. Significance

This study establishes that both invasive SNM and non-invasive ENM are effective and safe treatments for children with refractory gastrointestinal motility disorders.

• Clinical Implication: ENM should be considered a first-line neuromodulatory option for functional constipation to avoid surgical risks, particularly in patients without severe comorbidities. SNM remains the preferred option for children with complex comorbidities or those requiring continuous, uninterrupted stimulation (e.g., for urinary incontinence).
• Paradigm Shift: The findings support a multimodal therapeutic approach where neuromodulation is utilized before resorting to irreversible surgical interventions like ostomies or colectomies.
• Future Directions: The study highlights the need for standardized stimulation parameters and further research into the mechanistic differences between surface and implanted stimulation to optimize pediatric outcomes.

Limitations: The study was single-center, non-randomized (due to recruitment bias), and lacked blinding. The small sample size and heterogeneity of underlying pathologies (e.g., Hirschsprung disease vs. functional constipation) limit generalizability, though it reflects real-world clinical populations.