Specialist SCI respiratory care · UK
Diaphragm pacing for high-cervical spinal cord injury, an alternative to the ventilator.
A small implanted system that stimulates the diaphragm to breathe - for the right patient, it means fluent speech, a restored sense of smell, fewer chest infections and life away from a ventilator.
The pathway
What the assessment, surgery and conditioning cost - and how long each part takes.
A specialist SCI pathway is priced on the case.
In short
Workup, implant, then 3 to 6 months of conditioning - the ventilator stays as backup throughout.
| Step | Cost | Typical duration | Setting |
|---|---|---|---|
| Phrenic nerve conduction study | On request | 60 min | Same visit |
| Diaphragm fluoroscopy assessment | On request | 30 min | Same visit |
| Pulmonary function testing | On request | 45 min | Same visit |
| Avery Mark IV phrenic nerve pacemaker | On request | Half-day GA | Inpatient stay |
| Synapse NeuRx DPS diaphragm system | On request | 2–3 hr GA | Inpatient stay |
| Pacing conditioning programme (3–6 months) | On request | Outpatient | Weekly review |
Diaphragm pacing is a specialist commission. Costs vary by centre, by choice of Avery or NeuRx hardware, and by the length of the inpatient stay.
The problem
A ventilator keeps you alive. Diaphragm pacing lets you live with it.
For high-cervical SCI patients with intact phrenic nerves, long-term positive-pressure ventilation is not the only option - and often not the best one for speech, smell and community life.
-
Which system is right?
Avery Mark IV (phrenic nerve cuff) or NeuRx DPS (diaphragm electrodes) - the surgeon and respiratory physician decide together.
-
What happens next?
Surgery is only the start. A 3 to 6 month conditioning programme rebuilds the diaphragm before the ventilator hours come down.
The journey
From workup to community life - what happens, in order.
One SCI centre, one respiratory physician, one plan - through workup, surgery, conditioning and discharge.
Phase 1 · Workup
Assessment and system choice
Phase 2 · Surgery
Implantation and short stay
Phase 3 · Conditioning
3 to 6 months, then community
- 02
Workup
Phrenic nerve workup
Phrenic nerve conduction studies, fluoroscopy of diaphragm movement, and pulmonary function testing decide whether pacing is even possible.
- 03
Workup
System and route chosen
Avery Mark IV (phrenic nerve cuff, thoracoscopic) or Synapse NeuRx DPS (intramuscular diaphragm electrodes, laparoscopic) - agreed with the surgeon.
- 04
Surgery
Implantation surgery
Under general anaesthetic, in a thoracic or laparoscopic theatre. Electrodes placed, tunneled leads, external stimulator connected.
- 05
Surgery
Recovery from surgery
A short stay for wound and respiratory monitoring. The ventilator stays in place until conditioning begins.
- 06
Conditioning
Pacing conditioning, 3 to 6 months
Short pacing sessions lengthen week by week as the diaphragm rebuilds strength. Ventilator time drops on a planned schedule.
- 07
Conditioning
Full or part-time pacing, community
For many patients the ventilator comes off in daytime, then overnight. Tracheostomy weaning and community integration follow.
Typical workup to surgery: 6–12 weeks. Conditioning to full or part-time pacing: 3–6 months.
When it helps
When diaphragm pacing is the right step.
The classic indications, the quality-of-life drivers, and the one red flag that rules pacing out completely.
-
High cervical SCI (C3–C5)
A ventilator-dependent injury above C5 with intact phrenic nerve lower motor neurones is the classic indication.
-
Congenital central hypoventilation
CCHS (Ondine’s curse) - children and adults who stop breathing in sleep despite an intact chest wall.
-
ALS with preserved phrenic function
Selected motor neurone disease patients with early diaphragm weakness and preserved phrenic conduction, in specialist centres.
-
Long-term ventilator dependency
Where the tracheostomy and ventilator are the barrier to speech, smell, community life and infection-free lungs.
-
Recurrent chest infections on vent
Pacing restores negative-pressure breathing, which clears secretions better than positive-pressure ventilation.
-
Speech and sense of smell lost
Ventilated patients often lose fluent speech and olfaction - pacing can restore both by re-establishing normal airflow.
-
Community and travel
A backpack-sized external stimulator is far more portable than a ventilator - a driver of the referral for many patients.
-
Red flag: absent phrenic conduction
If phrenic nerve conduction studies show no response, pacing will not work - the lower motor neurone must be intact.
System options
Avery Mark IV or NeuRx DPS - and everything in between.
Two implantable systems dominate diaphragm pacing today. This is what each one actually involves.
-
Avery Mark IV (phrenic nerve cuff)
FDA-approved for decades. A cuff electrode is placed on the phrenic nerve in the chest via video-assisted thoracoscopic surgery.
-
Synapse NeuRx DPS (diaphragm)
Four intramuscular electrodes are mapped onto the diaphragmatic surface laparoscopically. Less invasive; faster conditioning.
-
Bilateral versus unilateral
Most adults are paced bilaterally for full tidal volumes. Unilateral pacing is used only in selected cases.
-
Full-time pacing
Once conditioning is complete, some patients pace 24 hours a day and come off the ventilator entirely, keeping the trache only for airway protection.
-
Part-time pacing
Others pace by day for speech, smell and mobility, and return to the ventilator overnight to rest the diaphragm.
-
Tracheostomy weaning
With stable pacing and safe swallow, some patients progress to decannulation. It is a staged, cautious process.
-
Paediatric CCHS pacing
Children with congenital central hypoventilation are paced overnight to free them from a nocturnal ventilator.
-
Reversal to ventilator
Pacing is not permanent by contract. If tolerance drops or hardware fails, the ventilator remains a safe fallback.
Safety and complications
What can go wrong - honestly.
Diaphragm pacing is safe when properly selected and conditioned. The ventilator remains the safety net throughout, and these are the risks worth planning for.
-
Electrode site infection
Any implanted hardware carries an infection risk. Prompt review of redness, discharge or fever at the electrode or receiver site is essential.
-
Hardware failure
Leads can fracture and receivers can fail. A pacing failure is not a breathing emergency because the ventilator remains available as backup.
-
Poor phrenic nerve response
A minority of implanted patients do not achieve useful tidal volumes. Conduction studies before surgery reduce, but do not eliminate, this risk.
-
Pacing-induced fatigue
Overdriving the diaphragm early causes fatigue and setbacks. The conditioning schedule is deliberately gradual for that reason.
-
Secretion clearance without cough
Pacing restores breathing but not a strong cough. Assisted-cough devices and suction remain part of daily care.
-
Aspiration risk
Swallow safety is assessed separately before any tracheostomy wean. Pacing on its own does not protect the airway.
-
Autonomic dysreflexia during pacing
High-cervical patients are prone to autonomic dysreflexia. The pacing programme is titrated to avoid triggering it.
-
Return to ventilator is a safe option
If pacing is not tolerated, going back to the ventilator is not a failure - it is the safety net the system was designed around.
-
Psychological impact of dependency shift
Moving from ventilator to pacing changes daily life, carer routines and identity. Psychological support is part of the pathway.
Reading your operation note
Your operation note in four parts. Read the last one first.
Whichever system was implanted, the note the surgeon and respiratory physician send you keeps to the same shape.
A quiet reminder
Surgical language is precise and can read coldly - we translate it for you.
If you would like us to talk you through the note before your review, just ask.
- 01 Header
Injury level and phrenic status
The neurological level, ASIA grade, and the phrenic nerve conduction findings that decided candidacy.
- 02 Technique
System, route and electrode placement
Whether an Avery Mark IV or NeuRx DPS was used, the surgical route, and the position and thresholds of each electrode.
- 03 Findings
Tidal volumes and pacing tolerance
The tidal volumes achieved on the table, initial pacing tolerance, and any per-operative issues with capture or fatigue.
- 04 Impression
Conditioning plan and ventilator wean
Read this first: the week-by-week pacing schedule, target hours off the ventilator, and criteria for tracheostomy decannulation.
Recognised by major UK insurers
Diaphragm pacing is a specialist commission; funding is usually arranged through the SCI centre and insurer together.
Frequently asked
Everything we get asked about diaphragm pacing.
Candidacy, systems, surgery, conditioning, life off the ventilator, and what can go wrong.
-
Who is a candidate for diaphragm pacing?
Adults and children with ventilator dependency and an intact phrenic nerve lower motor neurone. That covers most high-cervical SCI at C3 to C5, congenital central hypoventilation syndrome, and selected ALS patients. A phrenic nerve conduction study confirms candidacy.
-
How is the surgery done?
Under general anaesthetic. Avery Mark IV places a cuff on the phrenic nerve in the chest via video-assisted thoracoscopic surgery. Synapse NeuRx DPS places intramuscular electrodes on the diaphragmatic surface laparoscopically. Both tunnel leads to an external stimulator.
-
How long is the conditioning period?
Three to six months. The diaphragm has been unused for months or years and cannot take over immediately. Pacing sessions start at a few minutes and lengthen weekly under a respiratory physician’s programme.
-
Will I be able to come off the ventilator completely?
Many high-cervical SCI patients achieve full-time pacing and come off the ventilator entirely, keeping the tracheostomy for airway protection. Others pace during the day for speech, smell and mobility, and return to the ventilator overnight.
-
What are the benefits over a ventilator?
Fluent speech, restored sense of smell, fewer chest infections through negative-pressure breathing, easier community integration, and a portable external stimulator rather than a ventilator on a wheelchair.
-
What can go wrong?
Electrode site infection, hardware failure, poor phrenic nerve response, pacing-induced fatigue if pushed too hard, ongoing need for cough assist and suction, and - in a minority - a need to return to the ventilator.
Related tests