Spinal Cord Stimulator Service

The New Look

Introduction

• New MDT• Nature and History• Components• Mechanisms• Indications• Procedure• Evidence• Outcomes• The Future and what I’ve learnt

Introducing The Team

The new kids on the block

History

• 1965 Melzack and Wall

• 1967 Shealy

• 1970’s indiscriminate use poor follow up

• Neuropathic pain response

• EBM/cost effectiveness

Nature

• Electrical stimulation

• Direct nerve/field

• Nerve root

• Dorsal column

• Deep brain

• Motor cortex

Components

• Electrode• Connections• Battery (IPG) external/internal• Handset

Mechanisms

• Neuropathic

• Sympathetic

Mechanisms

• Gate theory• Spinal segmental inhibition (second order and

interneurones)• Supraspinal (via posterior columns)• Suppressed hyperexcitability in dorsal horns• Biochemical increased GABA decreased

excitatory glutamate and aspartate• Not blocked by naloxone• Adenosine dependent systems• Increased b-endorphins in CSF

Indications

• Neuropathic Pain not responding to conventional treatment

• Non nociceptive

• Intact dorsal column

Indications

• Peripheral neuropathic pain• FBSS/FNSS (70:30)• CRPS

• Refractory Angina• Critical limb ischaemia

• Other

Procedure

Evidence FBSS• North et al: Spinal cord Stimulation vs repeated Lumbosacral Spine surgery

for chronic pain: A Randomised Controlled Trial. Neurosurgery 56:98-107, 2005

• 50 patients randomised to SCS or reoperation 6month and 2 year f/u

• 45 followed up. SCS (9/19) more successful than reop (3/26) p<0.01

• Outcome measure: >50% VAS improvement and patient satisfaction

• Intention to treat

• More opioid use in post reoperation patients.

• No difference in ADLs or return to work.

Evidence FBSS

• Kumar et al: Spinal cord stimulation vs conventional medical management for neuropathic pain: A multicentre randomised controlled trial in patients with failed back surgery syndrome, Pain 132 (2007) 179–188

• 100 patients randomised to SCS plus CMM or CMM alone

• Intention to treat at 6 months 24/50 SCS and 4/44 CMM met primary outcome

• Primary outcome: >50% VAS improvement in leg pain, multiple secondary outcomes.

• Crossover allowed at 6 months

• SCS also improved QoL, functional capacity, Rx satisfaction.

Evidence: FBSS

• Two class 2 RCT’s

• Pooled case series 3307 patients 62% response

Cost effectiveness: FBSS

• Manca et al 6 month mean total cost 5x higher SCS vs CMT, but hrQoL much improved. Mean EQ-5D diff 0.21 at 6 months

• Kumar et al SCS US$24799 mean cost over 5 years vs US$33722 for CMM

• Qol 27% improvement (SCS), 12% improvement (CMM)

Cost effectiveness: FBSS

• North et al.

• SCS more effective, less expensive than reoperation.

• Systematic review concluded II-1 or II-2 with1B or 1C/strong recommendation for clinical use on a long term basis.

NICE-FBSS

• £10480 per QALY gained SCS/CMM vs CMM alone

• £9219 per QALY gained SCS vs reoperation

Complication rate: FBSS

• 43% overall one or more Cx

• Lead problems 27%

• Infections 6%

• Extension cable 10%

• Generator problems 6%

• Other eg CSF leak 7%

• No neurological complications

Evidence: CRPS I• Kemler et al: Spinal Cord Stimulation in Patients with Chronic Reflex Sympathetic

Dystrophy The New England Journal of Medicine Issue: Volume 343(9), 31 August 2000, pp 618-624

• 54 patients 36 SCS plus PT, 18 PT alone in Type I CRPS>6 months

• Assessed 6months/ 2 years/ 5 years

• VAS 6 months (-2.4cm, 0.2cm), 2 years (-2.1cm, 0cm), 5 years (-1.7cm, -1.0cm)

• HRQoL change 6 months (6% vs 3%), 2 years (7% vs 12%)

• Subgroup analysis at 5 years VAS (-2.5 vs -1.0) if received treatment allocated with SCS

• Pooled case series data (n=561) 67% responders. (CRPS I and II)

NICE - CRPS 1

• £16596 per QALY gained for SCS vs CMM

Refractory Angina

• Studies

• Reviews

• NICE guidance

Studies

• 8 medium to high quality studies• Variable numbers (n=12- n=104) overall 331 pts.• Decrease in anginal attacks• Improved functional status• Improved QoL• No effect on mortality, but less mortality than

CABG.• Complication rate 12%

Review

• Generally positive improvement in many outcomes.

• ESBY study (104 pts) SCS vs CABG showed similar analgesia, mortality, QoL after 5 years.

• CABG had better exercise capacity.

NICE on RA

• No study had demonstrated significant differences in pain outcomes.

• SCS seen to be comparable to CABG and PCI for functional outcomes.

• Benefits less certain than FBSS and CRPS

• May be useful for subgroups, but only to be used in the context of clinical studies.

Chronic Limb Ischaemia

• Non reconstructable limb ischaemia

• Cochrane review

• NICE guidance

Cochrane CLI

• Generally looking at limb salvage.• 6 studies with 450 patients• Pooled data limb salvage significantly

higher in SCS at 1 year vs CMM.• Analgesia equal in both groups, higher use

of opioids in CMM.• Risk of complications 17% (NNH=6)• Average 2 year cost: EUR 36500 SCS,

EUR 28600 CMM.

NICE on CLI

• Concluded no studies had shown statistically significant differences in outcomes SCS vs CMM

• May be subgroups with low peripheral O2 tension that benefit from SCS

• Insufficient evidence on survival, HRQoL and cost effectiveness.

• More trials needed.

Case series evidence

• Diabetic peripheral neuropathy

• CRPS II

• Peripheral nerve injury

• PHN

• Brachial plexus injury (partial)

• Amputation

• Partial spinal cord injury

Pooled Complication rate

• Overall 33% in CRPS studies, 43% in FBSS

• Dysfunction of stimulating apparatus mainly

• Medical complications mainly minor and treatable.

• Rarely major neurological complication

• Lead migration 13.2%

• Lead breakage 9.1%

• Infection rate 3.4%

• Hardware malfunction 2.9%

• Battery failure 1.6%

• Unwanted stimulation 2.4%

Early Audit

• 10 year audit

• 55% patients > 50% relief

Audit 2007

• Nov 2006-Dec 2007

• 12 implants (7 trials – 5 completed)

• 6 FBSS, 1 Cauda equina, 3 RA, 1 CRPS, 1 periph. Neuropathy.

• 36% > 50% relief

• Patient satisfaction 8/12 would undergo procedure again, 10/12 would recommend procedure.

Complications

• Infection 4

• Seroma 3

• Haematoma 1

• Dural puncture 2

• Lead movement 2

• Lead fracture 1

• Programmer failure 1

Audit 2008

• January 2008 – December 2008• 14 patients (15 implants) (5 trials, 2

completed)• FBSS 6, Radiculopathy 4, Cauda equina

1, RA 2, peripheral neuropathy 1.• 6/13 (46%) >50% pain relief• 6/13 reduced analgesic usage• Activity: 5/13 increase, 3/13 no diff. 5/13

reduced

• Patient satisfaction 10/13 would undergo again, 2/13 would not, 11 would recommend to others 1 would not.

Complications

• Reaction to implant antibiotic 1

• Significant movement artefact 1

• Lead movement 1

• System damage 1

Revisions

• Explantation 1

• Exploration 1

• Lead repostioned 1

• Failed revision 1

MDT

• Data on 37 new patients assessed jointly by psychol/physio.

• 6 straight to trial

• 9 not suitable

• 4 referred back for individ. Physio/psychol.

• 18 individ physio/psychol Rx (14 went on to trial SCS)

MDT assessment

• Assessment 1.5 hrs HAD TSK ODI

• Individual work up

• Trials

• Post implant physio review 6 weeks

• Long term F/U

• Resources: 3 physio sessions, 2 psychology.

Guidelines

• BPS

• NICE

• EFNS

Glasgow set up

• Referral (GG&C and outside)• Triage• Assessment• MDT discussion• Funding approval• Trial• Completion• Follow up

The what I’ve learnt bit!

• MDT and patient complexity• How enjoyable it is to work in a fully integrated

MDT setting.• Facing your fears, how hard surgery is!• Some interventions do work.• A good result is not always a good result…the

orthopaedic paradigm.• How to say no in the face of political pressure• How much we owe to Pete, Gavin, Anne and

Alison.

Questions?