Spinal cord stimulator implantation: Improving theatre efficiency

NICE MTG41 states that HF10 SCS implantation time is shorter and more predictable compared to paraesthesia mapped SCS.

Being a large tertiary centre that implants both types of SCS, we decided to assess if incision to closure time for implantation of anatomically placed (AP) HF10 SCS were shorter and more predicable than paraesthesia mapped (PM) SCS, with a view of optimising theatre efficiency.

Aim:

• To assess if HF10 SCS implantation was shorter and more predictable than PM SCS as suggested in MTG41.

Objective:

• Optimise theatre efficiency
• Minimise late finishes for theatre team
• Avoid on-the-day cancellation of patients

Leeds Teaching Hospitals NHS Trust is a large tertiary centre for the treatment of chronic neuropathic pain. Conventional SCS electrodes are placed posteriorly at the desired spinal level within the epidural space that corresponds with the dermatome pertaining to the patients’ neuropathic pain.

To confirm the lead is at the correct level, paraesthesia mapping is required to ensure full coverage of the painful area with stimulation. This interrupts surgery as it requires patients who have been sedated to be awake and able to articulate where they are experiencing the stimulation.

It requires programming configurations on the electrode and if necessary moving it until the desired area is obtained. In some cases, paraesthesia mapping took more time than expected resulting in over running lists and patient cancellations.

Over running lists caused obvious discontent among theatre staff, affecting morale. Cancellations and delays not only burden the team by adding to the long waitlist but also affects patient satisfaction and cost efficiency. Nevro Senza SCS delivering HF10 therapy for the treatment of chronic neuropathic back or leg pain after failed back surgery is recommended by NICE under medical technology guidance 41 (MTG41).

These SCS avoid the need for paraesthesia mapping (PM) and are anatomically placed (AP). HF10 SCS are thought to be as effective as low frequency SCS in reducing functional disability and pain without the need for paraesthesia.

In September 2017 we conducted a pilot study at the Trust where 10 full AP HF10 SCS were implanted on the same day by consultants in two separate theatres. The time taken to implant the HF10 SCS were compared to the time taken to implant the last 10 full PM SCS by the same consultants.

We found that the average time taken from incision to closure was less for both consultants when they implanted HF10 SCS. Besides, on statistical analysis, the variance was less for HF10 SCS compared to PM SCS - thus making them more time reliable. So when MTG41 was published in January 2019 stating the findings in our pilot study were reliable, we decided to see whether this can be assumed for all consultants at our tertiary centre.

The conditions in the pilot study were ideal, with all members of the team aware of the aim of the study to complete 10 cases in a planned day; whereas the PM SCS data was retrospective from regular lists. We wanted to see whether the pilot study findings are emulated in the 'real world'.

We included all SCS implanted (both trial and full) at Leeds Teaching Hospitals between January 2018 and January 2020 in the review.

The Trust’s theatre management system was used to collate this data. During the study period there were four consultants that had implanted at least 10 SCS at the Trust.

Implants completed by operators that had done less than 10 cases in the study period were excluded. We then analysed the time taken for each operator to implant a trial or full SCS using PM and AP, i.e. HF10.

We received no funding for this review and there were no costs incurred.

Key findings:

• A total of 440 SCS were implanted. 246 AP HF10 SCS and 194 PM SCS.
• Operators performed AP HF10 implants (trial and full) quicker than PM SCS (p=0.041)
• There was no statistically significant difference in time predictability (p=0.08) with similar standard deviations about the mean.
• Theatre lists can be planned per consultant irrespective of whether AP HF10 or PM SCS are implanted to minimise on-the-day cancellation.
• Assuming a standard five-hour theatre session, with 30 minutes for anaesthetic time and theatre turnover, more trials can be done per session when consultant 2 and 3 are present.
• Assuming a standard five-hour theatre session, with 30 minutes for anaesthetic time and theatre turnover, three full implants can be done with consultant 2 and two full implants with consultants 1,3 and 4.

• HF10 SCS are quicker to implant than paraesthesia mapped SCS.
• Implantation times for HF10 SCS are as predictable as paraesthesia mapped SCS.
• Theatre lists can be planned efficiently for both HF10 SCS and paraesthesia mapped SCS.
• Theatre lists must be tailored to consultant to avoid late finishes and cancellations.