1. Fundamentals of Spinal Cord
Stimulation (SCS)
Patient Selection: SCS
SCS may prove beneficial after failure of conservative therapy in
selected patients. At least 3-6 months of conservative therapy
should be attempted before SCS. Substance abuse issues must be
under control and further definitive surgery for treatment or cure
should have been exhausted before SCS is implanted.
It is strongly suggested that all patients who are to undergo a SCS
trial implantation or permanent implant have pre-operative
psychological screening. A face to face interview is always more
valuable than psychometric testing, however an MMPI or
Behavioral Health Index (BHI) may be obtained as a prelude to the
psychological interview. Such face to face encounters may reveal
personality disorders, homicidal tendency elucidation, etc. that
may not be apparent on psychometric testing. In addition, it is
suggested that a functional evaluation such as an Oswestry test be
incorporated along with physical capacity examination prior to
implantation or trial.
Good Candidates: 1. Peripheral Neuropathic Pain 2. CRPS
Marginal Candidates: Spinal Cord Etiology Pain
Poor Candidates: Mechanical Pain or Pain that is Not
Constant, eg. Can Find a Position In Which Pain
Is Completely Eradicated. Those with cerebral or cranial
etiology pain do not respond to SCS. Other poor
candidates are Those with untreated psychological
disorders esp. depression and anxiety disorders. Do not
implant SCS in schizophrenics or those with major
personality disorders or homocidal tendencies. Patients
who have 3/5 positive Waddells signs are not candidates.

2. NONORGANIC PHYSICAL SIGNS IN LOW BACK PAIN (Waddell Signs)
I.A Set of Five Types of Physical Signs
II.Can Be Used to Screen Individuals Who Require Detailed Psychological Assessment
III.Scoring
A.Any individual sign counts as positive for that type
B.Three or more types positive = clinically significant
IV.The Signs
A.Tenderness
1.superficial - skin is tender to light pinch over a wide area of lumbar skin
2.nonanatomic - deep tenderness over a wide area, not localized to one structure, often
extends to thoracic spine, sacrum, or pelvis
B.Simulation Tests - give the impression that an examination is being done, when in fact it is not
1.axial loading - vertical loading over the standing patient’s skull by the examiner’s hands -
may cause neck pain, but shouldn’t cause low back pain
2.rotation - turn standing patient to one side by rotating lower extremities (not spine)
C.Distraction Tests - reevaluating a positive finding while the patient’s attention is not focused
on the test - distraction must be nonpainful, nonemotional, and nonsurprising
1.indirect observation - can patient move the body part without pain when not being directly
examined?
2.straight leg raise - if positive when examined supine, do "flip test" (sitting SLR) - can be
done while testing for Babinski sign while sitting - if no pain in sitting then distraction sign is positive
D.Regional Disturbances - widespread divergence from accepted neuroanatomy
1.weakness - "cogwheeling" or many muscle groups that cannot be explained
neuroanatomically
2.sensory - "stocking" distribution of sensory changes
E.Overreaction
1.disproportionate verbalization, facial expression, muscle tension and tremor, collapsing,
sweating
2.most difficult type of sign to assess because:
a.cultural variation
b.examiner bias
Waddell G, McCulloch JA, Kummel E, Venner RM: Nonorganic physical signs in low-back pain.
Spine, 5(2) 117-125, March/April 1980.
Special Situation Candidates: Peripheral vascular disease
without diabetes may respond to the vasodilatory effect of SCS.
Intractable angina patients who are at maximum medical
management and are not surgical or angioplasty candidates
may benefit from SCS. Interstitial cystitis and pelvic pain may
be treated with sacral nerve stimulation via the caudal canal
approach, retrocaudal approach, or transforaminal approach.

3. The effect of the psychological and behavioral involvement
with pain perception cannot be overemphasized and care
should be taken to sufficiently screen patients. Patients who
have significant deficits in the above require intensive
treatment followed by re-testing before any further discussion
of SCS transpires. Remember, once you implant a stimulator
in these patients, you are marrying them. Dance with them for
awhile before you jump into marriage.
Neuropathic Pain Diagnoses
Neuropathic pain diagnoses: peripheral
Sensory neuropathies
Diabetes
Proximal motor (mononeuritis multiplex)
Distal sensory (polyneuropathy)
Toxic
Vitamin deficiency (beri beri)
Collagen vascular diseases (PN)
Lead poisoning
Guillian-Barre
Leprosy
Ischemic
Hereditary
Etc
Peripheral nerve tumor
Neurofibroma
Cancer
Entrapment neuropathies
Carpal tunnel syndrome (median)
Cubital tunnel syndrome (ulnar)

4. Tarsal tunnel syndrome (tibial)
Etc
Nerve injury
Partial v. complete
Neuroma, neuroma-in-continuity
Plexopathy/plexus injury
Intercostal neuralgia
Post-rhizotomy, post-ganglionectomy pain
Post-herpetic neuralgia
Failed back surgery syndrome (radicular pain)
Neuropathic pain diagnoses: spinal cord
Spinal cord injury pain (SCIP) syndrome
Syringomyelia
Brachial plexus avulsion pain
Phantom pain (post amputation)
Multiple sclerosis
Post-herpetic neuralgia (?)
Post-cordotomy pain
Neuropathic pain diagnoses: cranial neuralgias and brainstem
Cranial neuralgias
Trigeminal neuralgia
Glossopharyngeal neuralgia
Geniculate neuralgia
Sphenopalatine neuralgia (cluster HA?)
etc
CVA (i.e., Wallenberg)
MS (trigeminal neuralgia)
Syringobulbia
Neuropathic pain diagnoses: cerebral
Post-stroke (Dejerine-Roussy syndrome or “thalamic pain”)
Neuropathic pain diagnoses: controversies
Reflex Sympathetic Dystrophy
Complex Regional Pain Syndrome (CRPS) I
“Sympathetically-Maintained Pain”
Or “Sympathetically Independent Pain”
Causalgia
CRPS II
Neuropathic pain diagnoses: controversies
What is known
Injured axons develop alpha-adrenergic receptor-like activity
This may permit a chemical “coupling” between sympathetic efferents and A/C fibers
A-beta fibers mediate most hyperalgesia
This may explain “sympathetically” dependant pain
Injured axons are mechanosensitive
This explains “Tinel’s” sign at neuroma
Injured axons become hyperactive with hypoxia
Entrapment? Poorly vascularized scar?
Dorsal root ganglia also become spontaneously active after nerve injury.
Ventral root afferents
Role in phantom pain?
WDR RFs increase in size
WDR thresholds change
WDRs become “sensitized” and respond to non-noxious stimulation (A-beta) with high frequency
discharge
? Signals pain

5. Some WDRs may degenerate
Excitotoxicity?
Spinal Cord Stimulation
Indications
Failed back surgery syndrome (leg>back pain)
Painful peripheral nerve injury
Reflex sympathetic dystrophy (RSD)
Amputation stump pains
Painful distal sensory neuropathies
Postherpetic neuralgia
“End-zone” pains of paraplegia
Intercostal neuralgia
Post-thoracotomy pain syndrome
Spinal Cord Stimulation
Technique
Golden rule of SCS
“ Stimulation-induced paresthesias must cover the painful area for effective pain relief. ”

6. Contraindications to SCS:
1. Cannot implant an IPG SCS in patients with demand
pacemakers
2. Since patients with SCS as of 2006 can never have another
MRI, those who will need MRIs in the future are not
candidates
3. Significant bony canal abnormalities which will divert the
leads during placement (eg. Severe spinal stenosis)
4. Cervical spinal stenosis (causes potential lead indentation of
the cord)
5. Uncorrected coagulopathy
6. Concurrent infection during time of implantation
7. Patient inability to understand or use controller devices
8. Failure to attain at least 60% relief or 60% increase in
function during the trial of SCS
9. Post operative diathermy, ultrasound, or microwave therapies
Theory of Spinal Cord Stimulation
SCS is thought to be effective secondary to stimulation of the dorsal horns which
subsequently interrupts neuronal signal flow through the spinothalamic tracts.
However, there may be multiple mechanisms of action as is illustrated in the review
below:
Spine 2002 Nov 15;27(22):2574-83
Spinal cord stimulation: mechanisms of action.
Oakley JC, Prager JP.
Northern Rockies Pain and Palliative Treatment Center, Billings, Montana 59101,
USA. joshir@aol.com
STUDY DESIGN: A literature review and synthesis were performed. OBJECTIVE: To
present the current understanding of the mechanisms of spinal cord stimulation
in relation to the physiology of pain. SUMMARY OF BACKGROUND DATA: Spinal
cord
stimulation has been used for more than 30 years in the armamentarium of the
interventional pain specialist to treat a variety of pain syndromes.
Traditionally used for persisting leg pain after lumbar spinal surgery, it has
been applied successfully in the treatment of angina pectoris, ischemic pain in
the extremity, complex regional pain syndrome Types 1 and 2, and a variety of
other pain states. This review presents the current status of what is known
concerning how electrical stimulation of the spinal cord may achieve pain
relief. METHODS: A literature review was conducted. RESULTS: The literature
supports the theory that the mechanism of spinal cord stimulation cannot be
completely explained by one model. It is likely that multiple mechanisms operate

7. sequentially or simultaneously. CONCLUSION: Some clinical or experimental
support can be found in the literature for 10 specific mechanisms or proposed
mechanisms of spinal cord stimulation.
Implant System Types
Currently there are three manufacturers of SCS implantable devices: ANS,
Advanced Bionics and Medtronic. ANS has implantable programmable
generator (IPG) systems, rechargeable generator, and radiofrequency
(RF) systems. AB
sells only rechargeable systems while Medtronic currently sells
rechargeable and IPG systems. IPG systems incorporate a battery and
stimulator generator in a sealed single unit which must be replaced when the
battery life has expired. Typically current IPG systems last 3-7 years, but
high current usage will cause a shorter life span, sometimes less than one
year. High amperage and high frequency stimulation are the strongest
determinants of early battery failure.
The rechargeable IPG units are smaller than the corresponding IPG units
and have solved some of the issues of limited battery life. Rechargeable
units are believed to last 5-10 years, although one must be wary of claims of
overzealous salesmen that state battery life may be up to 50 years. Most of
the units implanted today are rechargeable units.
Genesis (ANS) IPG

8. RECHARGEABLE IPG SYSTEMS
While there are advantages and disadvantages to each company’s system, it
is in general a good idea to implant devices only from companies that have a
long track record of spinal cord stimulation devices that thereby shows the
long term commitment to patients and physicians necessary for these
potentially lifetime devices. The long term service required is a non-
negotiable item and upstart companies may not have the finances or
commitment to assure they will be available 10 years later when system
revision is needed. The lead systems and generators are not necessarily
interchangeable between different companies.
The RF stimulation unit manufactured by ANS uses an external battery
pack/controller which transmits RF energy transcutaneously to a
subcutaneous radio receiver which is connected to the stimulator leads.
Advantages of such a unit include lack of expensive IPG surgical
replacement (rechargeable batteries are used in the control pack), expanded
programmability characteristics which is useful in complex or positionally
related pain, and the capability of a very high stimulation frequency which is
far higher than available in IPGs (this characteristic is useful in sacral nerve
stimulation). RF units are better suited to patients with normal to high
current demands during the SCS trial.
Disadvantages of RF systems include
convenience since there is an external antenna
ring which must be applied directly over the
receiver, minimum of one amp current (less is
often needed for nerve root stimulation such as
sacral nerve), inability to use the system in
water, and the need to change the rechargeable
batteries every day in the external battery pack.
This lack of convenience may be a great
deterrent in the use of RF units.
Since both rechargeable and non rechargeable IPG units are totally
implanted, there are no external components visible. ANS, AB, and
Medtronic provide an external control unit for their IPGs. Both IPG and RF
units may be connected to the leads with or without extension wires,
however Medtronic always uses extensions while with ANS this is optional.

9. Lead Types
Fundamentally there are
two types of lead:
percutaneous (round)
leads and neurosurgical
(flat) leads. The
percutaneous leads are
almost always used
during spinal cord
stimulator trials and by
pain medicine surgeons
during permanent
implants. The round
leads may be placed
through a 14ga Tuohy
needle into the epidural
space while the
neurosurgical lead arrays require a partial laminectomy performed by a neurosurgeon
(NS) or orthopedic spine surgeon (OSS). Round leads have a tendency to migrate more
often than neurosurgical leads, have less favorable spinal
stimulation characteristics (inadvertent and sometimes
painful stimulation of the fibers of the ligamentum
flavum), and may have slightly less transverse stimulation
profiles when dual leads are used. Flat lead placement
requires a NS or OSS, laminectomy, overnight hospital
stay, and may be difficult to guide to the proper level.
Whereas round leads are usually guideable in the spinal
canal from levels far distal to the final placement, flat leads
must be placed immediately under the final resting
position of the lead. In some practice situations, the pain
medicine interventionalist will place the trial leads while
the NS or OSS will perform the permanent implant with
the neurosurgical leads. In other practice situations, the
pain medicine interventionalist will perform both the trial
and the implantation of the permanent lead systems, but
using a round lead for permanent placement. While this is a political issue and
reimbursement issue (NS and OSS collect an additional fee for the laminectomy), the
issue of patient safety is a real consideration. Those without surgical skills or any
surgical training may wish to utilize the NS or OSS for permanent lead implantation.
Because the Medtronic and ANS lead systems are currently incompatible with AB
systems. In general, the generator and company must be chosen to match the leads,
however ANS has implantable conversion kits available to permit use of their generator
with the Medtronic leads. The chart below compares the differences in the percutaneous
leads:
Laminectomy

10. Electrodes Contact Size
(mm)
Electrode
Spacing (mm)
Vertebral
bodies covered
Pices Quad
(Medtronics)
4 3 6 1
Pices Quad
Compact
(Medtronics)
4 3 4 1
Pices Quad
Plus
(Medtronics)
4 6 12 2
Octrode (ANS) 8 3 4 2
Quatrode
(ANS)
4 3 4 1
Advantages of the octrode lead include less chance of having to replace the lead since it
spans a larger segment of spine. Reprogramming is possible. Disadvantages are the need
for having the lead completely parallel to the spine if migration concerns are a
consideration. Generally these are theoretical concerns with the trial leads since the trial
period is so short, but can be of significance with permanent lead implant. The
Medtronic Quad plus spans two vertebral spaces just as the octrode (ANS), but the
spacing between the electrodes is very large. Cross stimulation and adjacent electrode
coverage may be incomplete. The pices quad compact uses a compact lead design for
maximum programming flexibility, but spans only one vertebral body.
Since I have used both systems, it is my opinion that familiarity with the representative
and the system is the most important feature.
Trial Lead Placement
Typically, the spinal cord stimulator trials are 3-14 days, although the Belgian trials were
conducted for a period of 3 months with no evidence of an increased infection rate.
Types of SCS trials are:
1. Percutaneous temporary lead trials…use disposable leads which are less expensive
than the permanent leads. Later, the patient is brought back into the office and the
leads are simply pulled out at the end of the trial. If the trial is successful and the
patient meets all other criteria, a permanent lead system plus stimulator generator is
implanted approximately 1-4 weeks later. There should be at least one week of time
between the removal of the temporary leads and the permanent system implant in
order to permit the epidural tract to close. It is suggested this method of performance
of SCS trials be used when initially beginning to implant SCS or when there is a
question in the physician’s mind regarding appropriate patient selection.
2. Permanent lead placement with anchoring to the interspinous ligament with
concomitant extension wire use to connect the permanent lead to the trial box.
During generator (or RF receiver) implantation, the extension is removed through the

11. skin and discarded. This method saves a step of lead replacement. Many
experienced implanters are now using this method.
3. Neurosurgical lead initial placement with extension wire to the external trial box. As
above, with a successful trial, the extension wire is discarded and the generator
stimulator unit is implanted during the second step.he most important technical factor
in determining lead placement is knowing the corresponding anatomical level of
anticipated spinal stimulation with respect to the target pathology. The diagram
below demonstrates this.
Percutaneous Lead Placement for SCS
Trial
One or two leads are used for a SCS trial,
depending on the location of pathology and the
Dual
Octrode
Leads

12. need for cross stimulation between leads. For lower extremity pain and low back pain
coverage, the entry point into the ligamentum flavum is chosen to be L1-2 or L2-3 (it is
suggested for those inexperienced with epidural needle placement that L3-4 be the point
of entry in order to avoid the spinal cord). Needle placement is slightly paramedian,
usually on the side to be covered, at a rather acute angle to the skin when possible. Often
the entry point in the skin is at 1 to 1 ½ vertebral levels lower than that of the ligamentum
flavum penetration point. The glass syringe-saline loss of resistance
technique is
used with
occasional use
of iodinated
contrast
injection when
necessary.
Obviously,
fluoroscopy
must be used for
placement. Use
of cones and
filters is
suggested to
reduce radiation
exposure. Advancement is made under AP fluoroscopy true to the spine, ie. spinous
processes aligned in the middle of the spine. Typically, during lead advancement is made
on the same side as needle entry unless midline final placement is desired. Occasionally,
final lead placement on the contralateral side is used when advancement unilaterally is
not feasible due to anatomical considerations. During lead advancement, care must be
taken to avoid the lead’s tendency to “dive” anterior-laterally into the lateral gutter,
which often occurs when the lead tip moves lateral to a point halfway between the
spinous process and the medial pedicular line.. Use of the guidance angle on the lead tip
can help prevent this. As a first approximation, the
lead tip is placed in the T9-11 region dependent on
the pathology. Obstructions encountered during
advancement of leads include ligamentum flavum
or zygapophyseal hypertrophy, peridural fibrosis,
dorsal fat pad, Batson’s epidural venous plexus,
and dura. Care should be taken not to be too
vigorous in attempts to pass a lead when excessive
force is required lest spinal cord
damage or dural penetration
ensue. If the lead continues to
Tuohy Needle Placed with Temporary Lead
Dual
Quad
Leads

13. veer off the midline during lead placement, removal of the stylette from the lead followed
by introduction of a 20 degree bend on the stylette then replacement of the stylette in the
lead is helpful. Never externally intentionally bend the leads themselves as this may
cause lead fracture. Reserve any bending manipulations to the stylette. If placement is
not possible due to scar tissue, hypertrophied ligamentum flavum, or a small canal, care
must be taken on any further lead advancement due to potential injury. However, the use
of an Introde over the lead to stent the part of the lead in the epidural space between the
tip and the entry point into the epidural space may permit further lead advancement and
manipulation. Finally, use of a lead blank or a stiffer stylette may be necessary to create
lead passage.
After the patient is awake from anesthesia (we prefer to avoid midazolam be
used since this drug slows the patient response: propofol is the preferred sedative if any
sedation is used during lead placement), then stimulation is performed using a moderate
frequency 100-150 hz, and various cathodes are activated during advancement of the
amperage. Optimal placement is when the middle electrodes are active. If a low
stimulation current (<1 mA) is possible with good stimulation (feeling of a tingly
sensation covering the painful area), then the electrodes are closest to the ideal location.
When two leads are used, a staggered array is preferable as demonstrated above for final
placement. Increasing the frequency is sometimes needed for spreading the coverage
area, or alternatively, one may change the cathode/anode array. Cross stimulation from
one lead to that on the contra-lateral side is possible and is useful for primary low back
pain syndromes. High frequency stimulation (>300 hz) is sometimes necessary to
provide pain relief. (Bennet, Alo, Oakley, Feler 1999 "Higher frequencies of
stimulation were found to be essential in re-establishing pain control in 15.5% of the
patients using dual-octapolar systems. Of the 71 patients in this group, 11 lost pain
control in the presence of paresthesia coverage over the area of described pain. With
use of frequencies greater than 250 Hz (with no change or an increase in pulse
width), all had return of pain control”
Repositioning of the leads with the epidural needle still in place is sometimes necessary
when coverage dictates a placement alternative to the initial placement. Some physicians
utilize an Epimed RK needle which does not have the sheering quality as a Tuohy if they
are frequently advancing and retracting leads. Once final placement is assured, the lead
is either secured to the skin using benzoin or mastosol which is then covered with a clear
plastic dressing. Alternatively, the lead can be stitched into place. The programmer is
attached in the recovery area and the patient is sent home for a 3-14 day trial. During the
trial period, oral antibiotic coverage may be desirable. A positive trial is one in which
Crossover Lead Array for Bilateral Coverage with One Lead

14. 60% pain relief or 60% increase in function is possible, no painful stimulation, the
stimulation pattern covers the painful area, the patient is able to tolerate the sensation of
continuous stimulation of the back or extremities, etc. For many implanters, a higher
standard of 75% reduction in the constant burning pain is used (independent of
mechanical pain). After the completion of the trial period, the leads placed
percutaneously are removed in the office, and if successful, permanent implantation may
be scheduled anytime after one week has elapsed since lead removal.
The permanent implant system used is partially dependent on the amperage used during
the trial, patient convenience, and on whether the patient would ever be a candidate for a
replacement generator in the future (Medicaid does not pay facilities sufficiently to
implant spinal cord stimulation systems). Those utilizing high currents or voltage during
the trial may benefit from a RF system or rechargeable IPG since the battery life will be
depleted with that high of a current drain. Also, one may consider implantation of
neurosurgical leads in such an instance in order to reduce the current used (reduces power
consumption by 25-50%).
Cervical spinal cord trial lead placement should always be performed with a interlaminar
entry site at C7T1 or below. In up to 25% of patients, there is anatomically no posterior
epidural space above the level of C6, therefore just as with interlaminar epidural steroid
placement, advancement of a catheter or lead from below this level is desirable. It is
strongly suggested at least 10 lumbar epidural SCS be placed before advancing to
cervical levels.
Complications of Trial SCS Lead Placement
1. Superficial infection
2. Subdural puncture with resultant post-dural puncture headache (depends on the
experience of the physician)
3. Deep epidural infection (rare)
4. Meningitis (rare)
5. Local irritation without infection (common)
6. Lead migration (common)
7. Lead fracture (rare)
8. Spinal cord or nerve root injury
9. Patient intolerance of stimulation pattern
10. Shock due to patient inability to properly use programmer
11. Bleeding from around lead entry site
It is suggested that a log book be maintained with check off areas to assure proper follow
through and billing is achieved. The patients names are logged into the book followed by
spaces to write in clinical diagnosis, and checkoff spaces for conservative therapy failed,
not a candidate for definitive surgery, psych eval completed, physical therapy eval
completed, patient history and physical complete, trial date, success of trial, implant date,
follow up date for post operative visit. In addition, the type and number of leads should
be noted along with the specific system chosen. This log book will serve as a ready

15. reference for insurance and referral purposes, and will also permit ready access to
information which is needed in case of a problem or complication.
Comparison of Various Non Rechargeable SCS Generators
Genesis XP
(ANS)
Synergy
(Medtronics)
Renew (ANS)
Type IPG IPG RF
Amplitude 0-25 mA
(12.5V)
0-10.5V 0-12V
Pulse Width 52-507
microsecs
60-450
microsecs
10-500
microsecs
Current
Regulated
Yes No No
Size mm 70x58x14 76x61x15 50x35x15
Vol cm3 46 51 26
Weight g 81 83 30
Battery Capac
Amp-hrs
8.2 6.4 Rechargeable
External
No. electrodes 8 8 16
Lead
extensions
Optional Mandatory Optional
# programs 24 1 24
# stimulation
sets
2 2 8
Permanent System Implantation

16. Perhaps the most important feature in permanent system implantation is the
patient response to the trial lead. Other factors which are of paramount
importance are patient understanding of complications of permanent system
implantation. These include:
Lead complications: lead migration (25% of round leads), lead
fracture, lead disconnection from the generator or extension, cord
compression, epidural hematoma, epidural abscess, dural leak, spinal cord
injury during or after placement
Generator complications: migration with weight gain or too large of a
pocket, generator flip resulting in inability to program or access generator,
pain from generator over iliac crest or ribs, seroma, infection resulting in
removal of generator and leads, patient weight gain resulting in erosion of
stimulator or leads through the skin, shock, generator battery failure or early
depletion, potential for spinal cord injury due to diathermy or MRI, potential
for SCS failure due to airport magnetic screening.
System complications: gradual loss of pain relief (20%)
The ANS product warning is listed as follows:
Warnings/Precautions/Adverse Events
Safety has not been established for pregnancy or pediatric use.
Patients should not drive or use dangerous equipment during
stimulation. Systems may be affected by or adversely affect
cardioverter/defibrillators, external defibrillators, MRIs, diathermy,
ultrasonic equipment, electrosurgical equipment, radiation therapy,
theft detectors, security systems, and aircraft communications
systems. Adverse events may include: undesirable changes in
stimulation described by some patients as uncomfortable, jolting, or
shocking; epidural hemorrhage, hematoma, infection, spinal cord
compression, paralysis, chest wall stimulation, CSF leakage, pain at
implant site, seroma, allergic response, hardware malfunction or
migration, loss of pain relief, and surgical risks. Patient selection
criteria includes psychological origin for the pain, appropriate surgical
candidate, detoxification from narcotics, and availability of long-term,
post-surgical management.
Diathermy Therapy — Do not use short-wave diathermy, microwave
diathermy, or therapeutic ultrasound diathermy (all now referred to as
diathermy) on patients implanted with a neurostimulation system.
Energy from diathermy can be transferred through the implanted
system and cause tissue damage at the location of the implanted
electrodes, resulting in severe injury or death.
Diathermy is further prohibited because it may also damage the
neurostimulation system components resulting in loss of therapy,
requiring additional surgery for system implantation and replacement.
Injury or damage can occur during diathermy treatment whether the
neurostimulation system is turned "on" or "off." All patients are advised
to inform their health care professional that they should not be
exposed to diathermy treatment.

17. Potential complications should be discussed in detail with the patient prior
to permanent implantation, and should be included on the consent form.
Generally, neurosurgical lead placement requires an overnight hospital stay
whereas the flat lead placement, without a laminectomy, may be performed
as an outpatient implant. General anesthesia, MAC, or local anesthesia can
be used for permanent implantation. However, if during the permanent
implantation of the generator lead implantation is also performed, it is
suggested that MAC anesthesia be used. Local anesthesia is reserved for
patients in which the permanent leads have already been placed, and the
extension has also been placed. It is very painful to the patient to have the
tunneling of the lead from the spine to the pocket under strict local
anesthesia, therefore if the leads plus generator need implantation, MAC is
useful. General is not the preferred anesthetic during lead plus generator
placement surgeries since the patient does need to respond to questions
during lead placement. General anesthesia may be used if the permanent
leads were placed, anchored, and tunneled subcutaneously for the trial.
There is a report of spinal anesthesia being used during lead placement, but
this is fraught with potential problems both technically and medico-legally.

18. Permanent lead plus generator implantation uses scrupulous surgical skin
prep, IV antibiotics, and appropriate
anesthesia to provide a quiet field. One
such technique involves placement of
the leads percutaneously followed by
advancement of the leads through the
needles. A piggyback paramedian
approach may be used or a bilateral
paramedian approach
for dual lead
placement. Once the
leads have been tested
to cover the
appropriate area with
the patient awake and
responsive, an incision
is made around the
lead and carried down
to the intraspinous
ligament. A lead anchor is placed over the lead
which is subsequently secured to the
interspinous ligaments with non-absorbable
suture. This is the most critical part of
permanent implantation, and Medtronics has
adopted the tact of using 4 separate anchoring
sutures into the interspinous ligaments. Deep
retractors may be needed for such procedure
and hemostasis is attained through
electrocautery. Once the lead is anchored
securely, the generator pocket is developed by a
separate incision in the subcutaneous tissues
above the gluteus musculature. Some
implanters prefer to use a lateral or anterolateral abdominal pocket, but this
is technically more difficult. The pocket is developed rather superficially
since the generator must communicate through the skin with the RF powered
programmer. A tunneling device is used to pass the leads from the spinous
incision to the generator pocket. In the case of Medtronics products, a lead
extension is used due to the short length of the leads, whereas with the ANS
products, the extension is optional. Silastic boots are used over the lead
connection points and are secured with silk ties. The generator itself does

19. developed by a
separate incision in
the subcutaneous
tissues above the
gluteus musculature.
Some implanters
prefer to use a lateral
or anterolateral
abdominal pocket,
but this is technically
more difficult. The
pocket is developed
rather superficially
since the generator
must communicate
through the skin with
the RF powered
programmer. A tunneling device is used to pass the leads from the spinous
incision to the generator pocket. In the case of Medtronics products, a lead
extension is used due to the short length of the leads, whereas with the ANS
products, the extension is optional. Silastic boots are used over the lead
connection points and are secured with silk ties. The generator itself does
not require suturing to underlying tissues. This necessitates the development
of a pocket that is just very slightly larger than the generator itself in order to
maintain generator orientation with the receiver side of the generator
directed towards the skin. SCS leads are secured to the generator with set
screws. ANS uses a torque screwdriver which prevents overtightening.
Final skin closure is in layers with a subcutaneous absorbable suture, and
skin staples or subcuticular stitch for superficial closure. In the case of the
Renew RF system, it is
not activated for about 10
days after implantation to
allow skin healing. The
IPG systems may be
activated immediately.
Post operative
instructions include
avoidance of trunk
flexion, no lifting or
elevation of hands above

20. the head or sleeping prone for at least 3 weeks, no immersion bathing or
showering until the post operative checkup at 7-10 days, no massages for at
least 2 months, no vigorous exercise for at least 2-3 months.
SCS Success Rates for Various Conditions (Kim Burchiel, MD)
Overall 50% of patients who received a SCS trial lead had a successful permanent
implant, but 78% of those with a successful trial had a successful permanent implant.
The relatively low overall success rate above demonstrates poor patient selection. This
underscores the need for SCS trials to effectively screen patients before a permanent
spinal cord stimulator implantation system. Obviously, patient selection plays a great
part in determining success. Patients without significant psychological aberrations and
who are competent without histrionic behavior and have peridural fibrosis with radicular
pain are far more likely to have a successful trial and implant than those patients with
multiple psychiatric diseases and generalized pain disorders. The better we become at
patient selection before trial SCS lead placement, the better will be our rate of successful
trials and ultimately successful permanent implants.
Selected Additional SCS Outcome Studies:

21. Neurology 2002 Oct 22;59(8):1203-9
Economic evaluation of spinal cord stimulation for chronic reflex sympathetic
dystrophy.
Kemler MA, Furnee CA.
Department of Surgery, Maastricht University Hospital, Maastricht, The
Netherlands. kemlerm@mzh.nl
OBJECTIVE: To evaluate the economic aspects of treatment of chronic reflex
sympathetic dystrophy (RSD) with spinal cord stimulation (SCS), using outcomes
and costs of care before and after the start of treatment. METHODS: Fifty-four
patients with chronic RSD were randomized to receive either SCS together with
physical therapy (SCS+PT; n = 36) or physical therapy alone (PT; n = 18).
Twenty-four SCS+PT patients responded positively to trial stimulation and
underwent SCS implantation. During 12 months of follow-up, costs (routine RSD
costs, SCS costs, out-of-pocket costs) and effects (pain relief by visual
analogue scale, health-related quality of life [HRQL] improvement by EQ-5D) were
assessed in both groups. Analyses were carried out up to 1 year and up to the
expected time of death. RESULTS: SCS was both more effective and less costly
than the standard treatment protocol. As a result of high initial costs of SCS,
in the first year, the treatment per patient is $4,000 more than control
therapy. However, in the lifetime analysis, SCS per patient is $60,000 cheaper
than control therapy. In addition, at 12 months, SCS resulted in pain relief
(SCS+PT [-2.7] vs PT [0.4] [p < 0.001]) and improved HRQL (SCS+PT [0.22] vs PT
[0.03] [p = 0.004]). CONCLUSIONS: The authors found SCS to be both more
effective and less expensive as compared with the standard treatment protocol
for chronic RSD.
Neurosurgery 2002 Aug;51(2):381-9; discussion 389-90
Spinal cord stimulation electrode design: prospective, randomized, controlled
trial comparing percutaneous and laminectomy electrodes-part I: technical
outcomes.
North RB, Kidd DH, Olin JC, Sieracki JM.
Department of Neurosurgery, School of Medicine, Johns Hopkins University,
Baltimore, Maryland 21287-7713, USA. rnorth@jhmi.edu
OBJECTIVE: The clinical use of spinal cord stimulation for treatment of chronic
intractable pain has been increasingly successful because of recent technical
improvements, particularly the development of multiple-contact electrodes
supported by programmable implanted pulse generators. Contemporary electrodes
can be placed percutaneously in some cases and require a limited laminectomy in
other cases. METHODS: We performed a prospective, randomized, controlled trial
comparing two prototypical electrode designs, using a computerized system that
allows direct patient interaction and quantitative measurements. A series of 24
patients with chronic lumbosacral pain syndromes first underwent testing with
percutaneous four-contact electrodes and then underwent implantation, at the
same spinal level, of one of two different electrode configurations; 12 patients
received a new percutaneous four-contact electrode of the same design and 12
received an insulated four-contact array, which was implanted via laminectomy.

22. RESULTS: The insulated array performed significantly (P = 0.0005-0.0047) better
than the temporary percutaneous electrode for the same patients, according to
all three measures tested (ratings of paresthesia coverage of pain, coverage
calculated from patient drawings, and amplitudes), at the "usage" amplitude for
the three standard bipoles examined. The insulated array also performed
significantly (P = 0.0000-0.026) better than the permanent percutaneous
electrode in terms of coverage ratings and amplitude requirements. Low back
coverage ratings were significantly better for the insulated array than for the
temporary percutaneous electrode, and scaled amplitudes necessary for low back
coverage were significantly better for the permanent percutaneous electrode than
for the temporary electrode. In comparison with the percutaneous temporary
electrode, at subjectively identical stimulation intensities, the permanent
insulated array required significantly lower amplitude. CONCLUSION: We can
immediately infer from these technical data that the use of an insulated array,
in comparison with a percutaneous electrode, would double battery life. Extended
follow-up monitoring will be required to assess the extent to which the
technical advantages we observed for the insulated array might be associated
with improved clinical outcomes.
Neurosurgery 1995 Jun;36(6):1101-10; discussion 1110-1
Prognostic factors of spinal cord stimulation for chronic back and leg pain.
Burchiel KJ, Anderson VC, Wilson BJ, Denison DB, Olson KA, Shatin D.
Division of Neurosurgery, Oregon Health Sciences University, Portland, USA.
Spinal cord stimulation (SCS) has been used for more than 20 years in the
treatment of diverse pain conditions. Although recent studies have identified
more clearly those conditions for which SCSoffers a favorable prognosis, the
identification of a patient population in whom reasonably long-term success can
be expected has been difficult. In an effort to improve patient selection and
increase the overall success rate of treatment, we have examined various
physical, demographic, and psychosocial variables as predictors of SCS outcome.
The study population consisted of 40 patients with chronic low back and/or leg
pain, 85% of whom were diagnosed with failed back surgery syndrome. Medical
history and demographic data were collected as part of an initial assessment
along with patient responses to the Minnesota Multiphasic Personality Inventory,
the visual analogue pain rating scale (VAS), the McGill Pain Questionnaire, the
Oswestry Disability Questionnaire, the Beck Depression Inventory, and the
Sickness Impact Profile. Treatment outcomes were examined and found to improve
significantly after 3 months of stimulation. Subsequent regression analysis
revealed that patient age, the Minnesota Multiphasic Personality Inventory
depression subscale D, and the evaluative subscale of the McGill Pain
Questionnaire (MPQe) were important predictors of posttreatment pain status.
Increased patient age and D subscale scores correlated negatively with pain
status, as measured by the percentage of changes in pretreatment and
posttreatment VAS scores, % delta VAS. In contrast, higher MPQe correlated with
improved pain status. By the use of the following equation and the definition
commonly associated with SCS success (at least 50% decrease in the VAS pain

23. level), the success or failure of 3 months of SCS was correctly predicted in 88%
of the study population. Our results suggest that patient age, Minnesota
Multiphasic Personality Inventory depression, and MPQe may be clinically useful
in the prediction of pain status after 3 months of SCS in patients with chronic
low back and/or leg pain. % delta VAS = 112.57 - 1.98 (D)-1.68 (Age) + 35.54
(MPQe).
Z Orthop Ihre Grenzgeb 2002 Nov-Dec;140(6):626-31
[Spinal Cord Stimulation (SCS) using an 8-pole Electrode and Double-Electrode
System as Minimally Invasive Therapy of the Post-Discotomy and Post-Fusion
Syndrome - Prospective Study Results in 34 Patients]
[Article in German] Rutten S, Komp M, Godolias G.
Klinik fur Orthopadie am Lehrstuhl fur Radiologie und Mikrotherapie, Universitat
Witten/Herdecke, Ressort Wirbelsaulenchirurgie und Schmerztherapie,
St.-Anna-Hospital Herne, Deutschland (Direktor: Prof. Dr. med. Georgios
Godolias).
AIM: Therapy of a pronounced post-discotomy (PDS) and post-fusion syndrome (PFS)
is often unsatisfactory because of the complexity and multifactorial pain
genesis. If surgical interventions cannot promise relief and if the entire
interdisciplinary spectrum of conservative treatment measures is inadequate, the
area of neuromodulative procedures offers spinal cord stimulation (SCS). The
objective of this study was to examine the therapeutic possibilities of SCS
using an 8-pole electrode and double electrode system in PDS and PFS with
extensive back-leg pain areas. METHOD: An appropriate SCS system was implanted
in 34 patients with PDS and PFS. Follow-up examinations were made prospectively
over a period of 24 months using general criteria and psychometric test
measuring instruments validated for German-language use. RESULTS: An 8-pole
double electrode system was implanted 23 times, a single electrode sufficed in
11 cases. The area of pain was covered in all patients. This required special
technical capabilities of the SCS system. The results remained constant over 24
months. The morphine dose could be reduced by at least 50 %. All measuring
instruments confirmed a clear reduction in pain and improvement in quality of
life as a result of SCS implantation. CONCLUSION: The SCS is an minimally
invasive surgical procedure which can enlarge the therapeutical possibilities of
pronounced PDS and PFS resistant to other modes of treatment. Special technical
possibilities of parameter setting are required to cover the pain areas.
Spine 2002 Nov 15;27(22):2584-91; discussion 2592
Spinal cord stimulation for chronic pain of spinal origin: a valuable long-term
solution. North RB, Wetzel FT.
Department of Neurosurgery, Johns Hopkins University School of Medicine,
Baltimore, Maryland 21287, USA. rnorth@jhmi.edu
STUDY DESIGN: A literature review was conducted. OBJECTIVE: To review the
indications and efficacy of spinal cord stimulation, particularly in reference

24. to chronic pain of spinal origin. SUMMARY OF BACKGROUND DATA: The first
spinal
cord stimulation was implanted by Shealy in 1967 via a subarachnoid route. Early
systems were plagued with a high rate of complications and technical problems.
With the evolving technology, especially the advent of multichannel programmable
systems and more precise epidural placement, the ability of spinal cord
stimulation to treat various pain syndromes improved. This article reviews the
literature on spinal cord stimulation from 1967 to the present. METHODS: The
literature is reviewed, with a particular focus on recent studies investigating
the efficacy of spinal cord stimulation for low back pain. RESULTS: Most studies
are limited by the same flaws, namely, retrospective study design. At this
writing, the few published randomized prospective studies have suggested that
spinal cord stimulation may be superior to repeat surgery. Complication rates
have declined to approximately 8%, and reoperation is necessary in approximately
4% of patients. When current percutaneous techniques are used, a lead migration
rate lower than 3% may be achieved. For certain topographies, laminotomy leads
may be superior, particularly with regard to low back pain. CONCLUSIONS: The
ultimate efficacy of spinal cord stimulation remains to be determined, primarily
because of limitations associated with the published literature. However, on the
basis of the current evidence, it may represent a valuable treatment option,
particularly for patients with chronic pain of predominantly neuropathic origin
and topographical distribution involving the extremities. The potential
treatment of other pain topographies and etiologies by spinal cord stimulation
continues to be studied.
Cardiology 2003;99(1):20-4
Cost-Effectiveness of Spinal Cord Stimulation versus Coronary Artery Bypass
Grafting in Patients with Severe Angina Pectoris - Long-Term Results from the
ESBY Study.
Andrell P, Ekre O, Eliasson T, Blomstrand C, Borjesson M, Nilsson M, Mannheimer
C.
Multidisciplinary Pain Centre, Sahlgrenska University Hospital/Ostra, Goteborg,
Sweden.
The present study is a 2-year follow-up of the 104 patients participating in the
ESBY study (Electrical Stimulation versus Coronary Artery Bypass Surgery in
Severe Angina Pectoris), a randomised prospective study including patients with
increased surgical risk and no prognostic benefit from revascularisation.
Hospital care costs, morbidity and causes of death after spinal cord stimulation
(SCS) and coronary artery bypass grafting (CABG) were assessed, as well as the
complication rate of SCS treatment. SCS proved to be a less expensive
symptomatic treatment modality of angina pectoris than CABG (p < 0.01). The SCS
group had fewer hospitalisation days related to the primary intervention (p <
0.0001) and fewer hospitalisation days due to cardiac events (p < 0.05). The
groups did not differ with regard to causes of death. There were no serious
complications related to the SCS treatment. Copyright 2003 S. Karger AG, Basel

25. Anesth Analg 2002 Mar;94(3):694-700; table of contents
Spinal cord stimulation in postherpetic neuralgia and in acute herpes zoster
pain.
Harke H, Gretenkort P, Ladleif HU, Koester P, Rahman S.
Department of Anesthesia and Pain Therapy, Klinikum Krefeld, Krefeld, Germany.
We studied the effects of spinal cord stimulation (SCS) on postherpetic
neuralgia (PHN). Data of 28 patients were prospectively investigated over a
median period of 29 (quartiles 9--39) mo. In addition, four patients with acute
herpes zoster (HZ) pain were studied simultaneously. After intractable pain for
more than 2 yr, long-term pain relief was achieved in 23 (82%) PHN patients
(median, 70 yr) during SCS treatment confirmed by a median decrease from 9 to 1
on the visual analog scale (P < 0.001). In five cases with serious comorbidity,
the initial pain alleviation could not be stabilized. Spontaneous improvement
was always confirmed or excluded by SCS inactivation tests at quarterly
intervals. Eight patients discontinued SCS permanently because of complete pain
relief after stimulation periods of 3--66 mo, whereas 2 reestablished SCS
because of recrudescence after 2 and 6 mo. Considerable impairments in everyday
life, objectified by the pain disability index, were also significantly improved
(P < 0.001). In 4 patients with acute HZ pain, SCS was promptly effective and
after periods of 2.5 (quartiles 2--3) months the pain had subsided. SCS seems to
offer a therapeutic option for pharmacological nonresponders. IMPLICATIONS: In
many patients with postherpetic neuralgia and acute herpes zoster pain is not
satisfactorily alleviated with pharmacological approaches. We report on 23 of 28
patients with postherpetic neuralgia and 4 of 4 with acute herpes zoster whose
chronic pain was improved by electrical spinal cord stimulation.
Am Surg 2001 Nov;67(11):1096-7
Clinical and objective data on spinal cord stimulation for the treatment of
severe Raynaud's phenomenon.
Neuhauser B, Perkmann R, Klingler PJ, Giacomuzzi S, Kofler A, Fraedrich G.
Department of Vascular Surgery, University Hospital Innsbruck, Austria.
Ischemic vascular disease of the upper extremity represents a difficult
therapeutic problem wherein medical treatment often fails. Epidural spinal cord
stimulation has been shown to be an effective alternative in severe peripheral
arterial disease. Although this method has been used for nearly two decades only
limited experience exists in Raynaud's phenomenon of the upper limbs. In
addition objective parameters to prove therapeutic success are not well defined.
Herein we describe a patient with severe primary Raynaud's phenomenon over
several years who had significant pain relief and complete healing of ischemic
digital ulcerations after spinal cord stimulation. Pain level was evaluated
using a visual rating scale before and after surgery. Microcirculatory
parameters were assessed before and after spinal cord stimulation by capillary
microscopy and laser Doppler anemometry. Significant improvement of red blood

26. cell velocity, capillary density, and capillary permeability was demonstrated.
At follow-up 18 months after surgery the patient had no complaints and all
ulcerations of her fingertips had healed. Spinal cord stimulation appears to be
an effective treatment in severe cases of Raynaud's phenomenon and we recommend
its use in the case of failed medical therapy. Pain rating and capillary
microscopy enable one to assess and visualize the effects of spinal cord
stimulation.
Br J Neurosurg 2001 Aug;15(4):335-41
Spinal cord stimulation--a long-term evaluation in patients with chronic pain.
Kay AD, McIntyre MD, Macrae WA, Varma TR.
Ninewells Hospital Medical School, Dundee, UK. adk4z@clinmed.gla.ac.uk
Spinal cord stimulation (SCS) is an established treatment modality for chronic
pain, angina pectoris, and peripheral vascular disease. This study evaluates
experience with SCS over a 13-year period with emphasis on surgical
complications, revisions and pain relief. It took the form of a retrospective
study of medical/surgical records coupled with a postal/telephone questionnaire.
The subjects consisted of seventy patients, aged from 21 to 76 years (mean 47;
median 46), with severe, chronic pain refractory to conventional treatment, who
underwent SCS implantation between 1984 and 1997. It investigated surgical
revisions, complications and pain relief. There were 72 surgical revisions
comprising electrode replacement/repositioning (32), generator replacement (22),
cable failure (6) and implant removal (12). Half the devices were revised within
3 years (95% confidence interval: 2-5 years) of implantation. Six (8.6%)
implants became infected. Sixty per cent of patients reported substantial relief
of pain. This study shows that the majority of patients undergoing SCS derive
significant benefit in terms of pain relief, but commonly require surgical
revisions due to both technical and biological factors. These devices require
systematic evaluation to determine optimal usage, clinical effectiveness and
cost-benefit analysis.
Eur J Pain 2001;5(3):299-307
Efficacy of spinal cord stimulation: 10 years of experience in a pain centre in
Belgium. Van Buyten JP, Van Zundert J, Vueghs P, Vanduffel L.
Department of Anaesthesia, AZ Maria Middelares, Hospitalstraat 17, B-9100 St.
Niklaas, Belgium. vanbuyten@skynet.be
Spinal cord stimulation is a minimally invasive mode of treatment in the
management of certain forms of chronic pain that do not respond to conventional
pain therapy. Several authors have reported encouraging findings with this
technique. Over a 10-year period in a single centre, 254 patients were subjected
to a trial period of spinal cord stimulation with an externalized pulse
generator. Two hundred and seventeen of the patients showed satisfactory results
justifying permanent implantation of a spinal cord stimulation system. In 1998,
an independent physician invited 153 patients (155 pain cases), who still had

27. the system in place and who could be contacted, for an interview. The aim of
this study was to evaluate the efficacy of an implanted spinal cord stimulation
system in terms of pain relief and quality of life and to assess the accuracy of
the patient selection criteria. The results of this study demonstrate a high
success rate as evaluated by the patients' own assessments--68% of the patients
rated the result of the treatment as excellent to good after an average
follow-up of almost 4 years. The resumption of work by 31% of patients who had
been working before the onset of pain supports these positive findings.
Copyright 2001 European Federation of Chapters of the International Association
for the study of Pain.
N Z Med J 2001 Apr 27;114(1130):179-81
Comment in:
N Z Med J. 2001 Aug 10;114(1137):365-6.
N Z Med J. 2001 Aug 10;114(1137):366.
Cost-effectiveness of spinal cord stimulation in patients with intractable
angina.
Merry AF, Smith WM, Anderson DJ, Emmens DJ, Choong CK.
Department of Anaesthesia, Green Lane Hospital, Auckland. glanaest@ahsl.co.nz
AIM: To review the cost of healthcare utilisation by patients suffering from
intractable angina, unsuitable for coronary revascularisation, before and after
treatment with spinal cord stimulation. METHODS: Data were collected for eight
patients treated for intractable angina with spinal cord stimulation at Green
Lane Hospital before April 1999. Information on consumption of specified medica
resources for the twelve months preceding implantation, the implantation period,
and the twelve months following implantation was collected. Where available,
data were also collected for the eighteen months preceding and following
treatment. RESULTS: In six patients successful permanent stimulation was
established; in two it proved technically impossible to implant a stimulator.
The six patients with successful stimulation spent fewer days in hospital
(p=0.028) and consumed fewer resources (p=0.046) following implantation than in
the period before implantation. The two patients for whom spinal cord
stimulation was unsuccessful spent more days in hospital and consumed more
resources in the twelve months following, than in the twelve months preceding
attempted implantation. Extrapolation of data for all eight patients suggests
that, on average, the cost of implanting a spinal cord stimulator will be
recovered in approximately fifteen months. CONCLUSION: Spinal cord stimulation
is a cost-effective treatment for intractable angina pectoris.
Neurosurgery 2001 May;48(5):1056-64; discussion 1064-5
Spinal cord stimulation for nonspecific limb pain versus neuropathic pain and
spontaneous versus evoked pain.
Kim SH, Tasker RR, Oh MY.
Department of Neurosurgery, Yeungnam University, Taegu, Korea.

28. OBJECTIVE: To compare the outcome of spinal cord stimulation (SCS) in patients
with nonspecific limb pain versus patients with neuropathic pain syndromes and
in patients with spontaneous versus evoked pain. METHODS: A retrospective review
of 122 patients accepted for treatment with SCS between January 1990 and
December 1998 was conducted. All patients first underwent a trial of SCS with a
monopolar epidural electrode. Seventy-four patients had a successful trial and
underwent permanent implantation of the monopolar electrode used for the trial
(19 patients), or a quadripolar electrode (53 patients), or a Resume quadripolar
electrode via laminotomy (2 patients). RESULTS: Of the 74 patients, 60.7%
underwent implantation of a permanent device and were followed for an average of
3.9 years (range, 0.3-9 yr). Early failure (within 1 yr) occurred in 20.3% of
patients, and late failure (after 1 yr) occurred in 33.8% of patients. Overall,
45.9% of patients were still receiving SCS at latest follow-up. Successful SCS
(>50% reduction in pain for 1 yr) occurred in 83.3% of patients with nonspecific
leg pain, 89.5% of patients with limb pain associated with root injury, and
73.9% of patients with nerve neuropathic pain. SCS was less effective for the
control of allodynia or hyperpathia than for spontaneous pain associated with
neuropathic pain syndromes. Third-party involvement did not influence outcome.
There was a lesser incidence of surgical revisions when quadripolar leads were
used than with monopolar electrodes. CONCLUSION: SCS is as effective for
treating nonspecific limb pain as it is for treating neuropathic pain, including
limb pain associated with root damage.
N Engl J Med 2000 Aug 31;343(9):618-24
Spinal cord stimulation in patients with chronic reflex sympathetic dystrophy.
Kemler MA, Barendse GA, van Kleef M, de Vet HC, Rijks CP, Furnee CA, van den
Wildenberg FA.
Department of Surgery, Maastricht University Hospital, The Netherlands.
mkeml@shee.azm.nl
BACKGROUND: Chronic reflex sympathetic dystrophy (also called the complex
regional pain syndrome) is a painful, disabling disorder for which there is no
proven treatment. In observational studies, spinal cord stimulation has reduced
the pain associated with the disorder. METHODS: We performed a randomized trial
involving patients who had had reflex sympathetic dystrophy for at least six
months. Thirty-six patients were assigned to receive treatment with spinal cord
stimulation plus physical therapy, and 18 were assigned to receive physical
therapy alone. The spinal cord stimulator was implanted only if a test
stimulation was successful. We assessed the intensity of pain (on a
visual-analogue scale from 0 cm [no pain] to 10 cm [very severe pain]), the
global perceived effect (on a scale from 1 [worst ever] to 7 [best ever]),
functional status, and the health-related quality of life. RESULTS: The test
stimulation of the spinal cord was successful in 24 patients; the other 12
patients did not receive implanted stimulators. In an intention-to-treat
analysis, the group assigned to receive spinal cord stimulation plus physical

29. therapy had a mean reduction of 2.4 cm in the intensity of pain at six months,
as compared with an increase of 0.2 cm in the group assigned to receive physical
therapy alone (P<0.001 for the comparison between the two groups). In addition,
the proportion of patients with a score of 6 ("much improved") for the global
perceived effect was much higher in the spinal cord stimulation group than in
the control group (39 percent vs. 6 percent, P=0.01). There was no clinically
important improvement in functional status. The health-related quality of life
improved only in the 24 patients who actually underwent implantation of a spinal
cord stimulator. Six of the 24 patients had complications that required
additional procedures, including removal of the device in 1 patient.
CONCLUSIONS: In carefully selected patients with chronic reflex sympathetic
dystrophy, electrical stimulation of the spinal cord can reduce pain and improve
the health-related quality of life.
Advanced
Techniques
SCS may be used to treat
interstitial cystitis through a
retrocaudal approach to the
caudal canal, through a trans-
sacrococcygeal ligament
approach, or trans-sacral
foraminally. With the trans-
sacrococcygeal ligament
approach (the easier of the
three), the leads are advanced
to the level of S1 and with the tips more lateral than the base. This places
the electrodes across the sacral nerves which can be stimulated by activating
specific electrodes. Obviously, this works best with the ANS octrode since
it possesses
sufficient length
and narrow
enough electrode
spacing to permit
highly selective
programming
over a long
distance. The
Pices compact
Retrocaudal Approach
Sacrococcygeal Ligament Approach

30. quad lead works best transforaminally or retrocaudally.
Peripheral nerve stimulation may also be used.
Occipital nerve stimulation is possible with a lateral approach placing the
lead directly over the x-ray
projection of C1 and across
the greater occipital nerve
subcutaneously.
The permanent generator is
implanted in the anterior
chest wall. This technique

31. often works extremely well for occipital neuralgia which responds to occip.
N. blocks.
Other peripheral nerves can be stimulated via the use of special flat leads
with suture wings placed directly on peripheral nerves. Below is a picture of
a dorsal scapular nerve stimulator placement.
Dorsal root ganglion stimulation is possible
by utilizing a trans-sacrococcygeal ligament
placement, then curving the lead out the
lateral foramen to the DRG. Stimulation at
this location requires very low current and
may be used for radicular pain which will
not be amenable to definitive surgical
intervention. Alternatively, placement of
the lead in the lateral gutter of the spinal
canal affords an opportunity to utilize low
current stimulation of specific target nerves.
Finally, utilization of spinal cord
stimulation for non-traditional uses continues to grow. In Europe, the
greatest use of SCS is not for low back or lumbar neurogenic pain, but for
peripheral vascular disease. Use of SCS in PVD affords vasodilation of
constricted vessels and improves circulation, except in advanced diabetes
patients. Use of SCS as an alternative treatment for intractable angina is

32. increasing in the US. There are also uses reported for facial pain via specific
trigeminal terminal branch stimulation. Obviously all these advanced
techniques require training with experts and should not be attempted without
appropriate training.
Useful Links
Advanced Neuromodulation Systems
www.ans-medical.com
Medtronics
www.medtronics.com
American Academy of Pain Medicine
4700 W. Lake
Glenview, IL 60025
Phone (847) 375-4731
Fax (847) 375-6331
http://www.painmed.org./
American Academy of Physical Medicine
and Rehabilitation
One IBM Plaza, Suite 2500
Chicago, IL 60611-3604
Phone (312) 464-9700
Fax (312) 464-0227
http://www.aapmr.org/
American Chronic Pain Association
P.O. Box 850
Rocklin, CA 95677-0850
(916) 632-0922
www.theacpa.org
American Neuromodulation Society
6287 Cheshire Lane North,
Minneapolis, MN 55311-4245
Phone (763) 559-4108

33. Fax (763) 559-4161
http://www.neuromodulation.org/
American Pain Foundation
11 South Calvert St.
Suite 2700
Baltimore, MD 21202
Phone (914) 351-1010
http://www.painfoundation.org/
American Psychological Association
750 First Street NE
Washington, DC 20002-4242.
Phone (202) 336-5500
www.apa.org
The American Society of
Interventional Pain Physicians
2831 Lone Oak Road
Paducah, KY 42003270
Phone (270) 554-9412
www.asipp.org
American Society of Regional
Anesthesia and Pain Medicine
P.O. Box 11086
Richmond, VA 23230-1086
Phone (804) 282-0010
Fax (804) 282-0090
http://www.asra.com
Arthritis Foundation
1330 Peachtree Street NW
Atlanta, GA 30309
Phone (800) 283-7800
www.arthritis.org
Canadian Pain Society
50 Driveway

34. Ottawa, ON K2P 1E2
Canada
Phone (613) 234-0812
Fax (613) 234-9894
http://www.medicine.dal.ca/gorgs/cps/
International Association for the Study of Pain®
909 NE 43rd St., Suite 306
Seattle, WA 98105-6020 USA
Phone (206) 547-6409
Fax (206) 547-1703
www.halcyon.com/iasp
International Neuromodulation Society
Thomas Jefferson University
1015 Chestnut Street, Suite 1400
Philadelphia, PA 19107
Phone (215) 955-4049
Fax (215) 923-4939
International Spinal Injection Society
10 Edgehill Way
San Francisco, CA 94127
Phone (415) 661-6177 or (888) 255-0005
Fax (415) 661-6179
www.spinalinjection.com/ISIS1/
National Pain Foundation
3070 South Williams
Denver, CO 80210
Phone (303) 756-0889
Fax (303) 692-8414
www.painconnection.org
World Institute of Pain (WIP)
http://www.wipain.org/
Government Resources
National Institutes of Health (NIH)

35. www.nih.gov
Pain and Neurological Disorders Information
National Institute of Neurological Disorders
Government web site that collects and disseminates
research information related to neurological disorders.
Phone (800) 352-9424
www.ninds.nih.gov/health_and_medical/disorder_index.htm
U.S. House of Representatives
www.house.gov/writerep/
U.S. Senate
www.senate.gov
Insurance and Reimbursement Information
Centers for Medicare and Medicaid Services
National healthcare insurance information and disease
coverage, eligibility, enrollment, publications, and state
contacts for questions; interactive database compares health
plan options.
Phone (800) 638-6833
www.hcfa.gov
The American and International Neuromodulation Societies are the premier
sources of information and advances in techniques via journal publication
and annual meetings. SCS, intrathecal therapies, functional motor
stimulation, and other advanced techniques are discussed. If you plan to
perform either trials or permanent implants of SCS, it is strongly suggested
you join the American Neuromodulation Society.