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Complications of Spinal Cord Stimulation: Identification, Treatment, and Prevention

Timothy R. Deer MD, C. Douglas Stewart PA/C, MBA
DOI: http://dx.doi.org/10.1111/j.1526-4637.2008.00444.x S93-S101 First published online: 1 May 2008


Spinal cord stimulation is a therapy used for the relief of neuropathic pain of the trunk and limbs. The therapy was first reported four decades ago, and has improved in many areas including technical equipment, patient selection, and physician training. Despite these advances, complications are still seen with both the implantation and long-term use of these devices. This article gives an overview of the identification, treatment, and follow-up care of patients suffering complications. A close analysis is also made of clinical assessment and actions that are important in reducing or preventing these sometimes devastating events.

  • Spinal Cord Stimulation
  • Complications
  • Prevention
  • Risks


Electrical current has been used to treat disease for thousands of years. The evolution of these therapies can be traced from Ancient Greeks using torpedo fish to treat arthritis and other disease states [1]. In the 1700s, several great minds worked on the concept of capturing electricity to be used to help the suffering. During that time period, energy was harnessed in crude capacitors called Leyden jars. Further work revealed that electricity is involved in muscle movement, neurological function, and pain perception. In regard to pain relief and neurological diseases, early reports were optimistic for the use of this treatment for headaches, joint pain, hysteria, and depression. The first recorded skeptic of these therapies was the American statesman, Benjamin Franklin. He reported that in his experience, the relief provided was often overridden by complications including skin burns and pain with increasing current and voltage. It is the goal of this paper to expand on Franklin's previous report and give a comprehensive look at current complications of spinal cord stimulation [2–4].

Much like the history of electrical therapies for the treatment of disease, spinal cord stimulation (SCS) has seen a major evolution since it was first reported in the literature four decades ago. Since the initial use of SCS by Shealy, the devices have changed from bipolar leads with an external power source to multi-contact leads with rechargeable generators. The technique involved with the placement of these implants requires the placement of a programmable lead into the epidural space by either a percutaneous needle approach or an open surgical approach [5]. Once the lead is in proper position, as determined by patient response or X-ray confirmation, a subcutaneous pocket is made and tunneling tool is used to place wires from the leads to a generator.

This technique is indicated in patients with moderate to severe pain of the limbs or trunk that has failed more conservative approaches. The most common disease states that are treated with SCS include failed back surgery syndrome, lumbar or cervical radiculitis, peripheral neuropathy, complex regional pain syndrome, post-herpetic neuralgia, spinal stenosis, pelvic pain, angina, ischemic pain, peripheral nerve injuries, and nerve plexus injuries [6]. Prior to moving forward with a permanent implant, the patient should have a trial that provides significant relief. They also must be psychologically stable, and if they suffer from comorbid depression, anxiety disorder, drug addiction, systemic infections, or bleeding disorders, these conditions must be successfully managed before proceeding [7].


Due to the inherent difficulty of identifying complications by peer review and closed claim analysis, the incidence of complications with SCS is unknown.

An overview of complications is provided in Table 1 based on information published by Turner and Cameron (see Table 1). Turner analyzed the available evidence-based studies over the past decade and found an overall complication rate of 34%, a complication rate leading to surgical revision in 23%, and a serious complication rate at less than 1% [8]. The accuracy of these stated rates are difficult to interpret because of the variability of the populations involved in the different studies. In some instances, the investigator may be more experienced than the typical implanter resulting in better overall outcomes, or the outcomes may be significantly worse because of the severity of the patient disease states and the demands of a teaching environment. In another analysis, Kumar found lead complication rates to be 5.3%, a low infection rate of 2.7%, and an epidural fibrosis rate of 19% [9]. The severity of complications varies from minor problems such as simple skin irritations or the need for computer programming to more dangerous complications such as epidural bleeding and paraplegia.

View this table:
Table 1

Complications associated with spinal cord stimulation and their diagnosis and treatment

Complications involving the neuraxis
Nerve injury  CT or MRI, emg/ncs/physical examSteroid protocol, anticonvulsants, neurosurgery consult
Epidural fibrosis  Increased stimulation amplitudeLead reprogramming, lead revision
Epidural hematoma  Physical exam, CT or MRISurgical evacuation, steroid protocol
Epidural abscess  Physical exam, CT or MRI, CBC, blood workSurgical evacuation, IV antibiotics, ID consult
Postdural puncture headache  Positional headache, blurred vision, nauseaIV fluids, rest, blood patch
Complications outside the neuraxis
Seroma  Serosanguinous fluid in pocketAspiration, if no response surgical drainage
Hematoma  Blood in pocketPressure and aspiration, surgical revision
Pain at generator  Pain on palpationLidoderm patches, injection, revision
Wound infection  Fever, rubor, drainageAntibiotics, incision and drainage, removal
Device-related complications
Unacceptable programming  Lack of stimulation in area of painReprogramming of device, revision of leads
Lead migration  Inability to program, X-raysReprogramming, surgical revision
Current leak  High impedance, pain at leak siteRevision of connectors, generator, or leads
Generator failure  Inability to read deviceReplacement of generator
  • CT = computed tomography; MRI = magnetic resonance imaging; IV = intravenous; CBC = complete blood count; emg = electromyograph; ncs = nerve conduction studies; ID = infectious disease specialist.

Preoperative Risk Reduction

Prior to surgery, the patient should be interviewed regarding preexisting deficits and complaints, which should be documented. Expectations should be discussed and the risk of complications should be outlined. Coexisting diseases and conditions should receive the focus of the clinician. Disease states that may benefit from preoperative intercession include psychiatric disorders, diabetes mellitus, immunological diseases, disorders of the coagulation system, recent infectious diseases, and other hormonal disorders. The goal of medical care prior to surgery is to have the primary care specialist maximize the care of the diseases or conditions present, thereby reducing the risk of postoperative complications. In some cases, a consultation by infectious disease specialists, endocrinologist, psychiatrists, or hematologists may be warranted. All components of the patients' health should be optimized prior to moving forward with implantation as risk reduction is an easier method of achieving a good outcome than having to manage complications. When possible, the patient should be removed from any drug that effects clotting for a time interval sufficient to normalize the effect on bleeding.

Patient education should occur during this period including the expectations of the therapy, expected outcomes, and common risks. This discussion should be documented and witnessed. The indications for the procedure should also be documented for help in insurance approval and reimbursement.

Trialing vs Permanent Implantation of the Device

Prior to moving forward with the scheduling and performance of the system, the physician should discuss the risks related to the needle and lead in the immediate procedural period, as distinct from the separate risks involved with making incisions, anchoring, and tunneling. The patient should understand that the risk of the trial revolves around the lead, needle, and anesthesia. The risks of the permanent device have the same acute worries, but there are additional risks associated with the surgical implantation and the long term use of the system. When considering these possible complications, the patient and the physician should have a frank discussion on the relatively low risk of the trial and comparatively increased risks of placing the device permanently. The patient and implanting doctor should also discuss the different methods of placing a permanent system through a percutaneous approach similar to the trial or the surgical lead approach which involves a more extensive surgical technique.

Intra-operative Risk Reduction

At the time of the procedure, the patient should be assessed for skin disorders or infection at the site of the needle entry or incision. The use of preoperative antibiotics is sometimes debated in regard to their utility or benefit. The most common organism to cause postoperative infections is gram positive bacteria such as Staphylococcus. The use of a third generation cephalosporin is recommended. In patients who are allergic to cephalosporins or penicillin, the use of vancomycin is recommended. In some facilities with a history of patients infected with resistant organisms such as methicillin-resistant Staphylococcus aureus, vancomycin is recommended as a first line agent. If the patient has had a previous history of staphylococcal infection, a consultation with infectious disease may be warranted in the preoperative period.

The patient should be prepped on each occasion over an area greater than 6 cm from the proposed surgical site with a solution found to be beneficial in the facility in which the procedure is being performed. Options include alcohol, Betadine and chlorhexidine. Draping should also be wide to the planned surgical field. The use of occlusive drapes can be helpful and they can be impregnated with prepping solutions.

Anesthesia options for SCS vary from local anesthesia to general anesthetics. The advantage of local anesthesia is that the patient may provide a more complete response to the stimulation pattern. Unfortunately, many patients cannot tolerate the procedure without some form of anesthesia. The use of conscious sedation with monitoring is helpful to enable the patient to tolerate the procedure while also remaining conversant and alert to reduce the risk of neurological damage. Some clinicians prefer to use deep sedation to improve patient satisfaction and to reduce motion during the procedure. However, the sedated patient does not identify nerve root pain to warn of impending difficulties, increasing the risk of complications due to injury to neural tissues. General anesthesia should be reserved for implanting surgical leads when direct visualization can be performed by the surgeon.

An alternate method of anesthesia in those undergoing a permanent implant is the use of epidural injection with local anesthetic. This can produce a surgical level of anesthesia for pocketing and tunneling. This technique should be avoided as it may lead to a delay in diagnosing an epidural bleed or nerve trauma.

Wound closure is a very important part of reducing the risk of infection. The wound should be closed in the usual fashion using either interrupted or running absorbable sutures and multiple layers to assure that all dead space is obliterated and there is no tension on the skin. The skin may be approximated with a subcuticular stitch, nylon, or staples.

A sterile nonocclusive dressing is applied over the wound and should remain undisturbed for 48–72 hours if the dressings are not grossly soiled; at this point, if the wounds are dry and there is no seepage, the patient may shower without disturbing the wounds. The surgical areas should be patted dry and then redressed with a sterile nonocclusive dressing.

Over the next few days the dressing may be changed daily. If the patient has staples or stitches, antibiotic ointment may be applied as according to the preferences of the operating surgeon. If the patient has been closed with a tape closure or surgical bonding agent, care should be used in the application of anything that might weaken the closure. In the immediate postoperative phase, the application of ice packs to the wound may be of benefit in helping to control swelling and pain.

If the patient has had staples or sutures, removal could occur anywhere from 7 to 10 days depending on the general health of the patient, body habitus, and condition of the wound. When the staples or sutures are removed, the wound should remain dry for approximately 24 hours to allow the holes and tracts left by the closure to seal.

Postoperative Risk Reduction

The patient should be monitored after surgery for any changes in neurological exam. The highest risk for bleeding is in the first 24 hours. In the days that follow implant, attention should be given to wound care and abnormalities. Stimulation patterns should be monitored and reprogrammed as needed in the first 6 weeks after surgery. When dual octapolar leads are used, in most cases the normal shifting of a percutaneous lead can be addressed with changing the pulse width or the position of the cathode.

Identification and Treatment of Complications

Neuroaxial Complications

The most disastrous complications that can arise during implantation of these devices involve the neuraxis. When invading the epidural space with a needle or rigid lead, the chance exists to puncture a blood vessel. In most cases, bleeding of these epidural vessels does not lead to a space occupying lesion. In some cases, an epidural hematoma can develop due to intrinsic clotting disorders, medications that effect clotting, or severe tears in the vessels. In most cases, these problems are limited, and the patient and physician remain unaware of the issue. When the lesion compresses the spinal cord or nerves, serious deficits can occur which may progress to paraplegia. Warning signs of epidural hematoma include postoperative numbness that may be accompanied by severe back or leg pain. If weakness develops, a vigilant search should occur for the cause of this problem. Risk factors for epidural hematoma include drugs that effect clotting, coexisting liver disease, blood disorders, difficult lead placement with multiple passes, surgical lead placement, and extensive bony insult in placing the lead. Diagnosis is made by a computed tomography (CT) scan of the area of needle insertion, lead insertion, and final lead placement. Magnetic resonance imaging (MRI) is contraindicated with an indwelling lead. In cases where the CT is inconclusive, the leads should be urgently removed and an MRI should be obtained [10–13]. When epidural hematoma is confirmed, treatment is by surgical evacuation within 24 hours of the injury [14]. Time is valuable to improving the chances of a full recovery. When an epidural hematoma is suspected, the radiologists, spine surgeon, and implanting doctor should work together to expedite the diagnosis and treatment of the problem.

In addition to epidural bleeding, vigilance is required to diagnose infections of the spinal structures. Infections can include meningitis, epidural abscess, and discitis. The incidence of these events is less than 1 in 1,000, and most infectious problems do not involve the neuraxis [15]. Epidural abscess should be suspected when there is severe pain at the lead implant site. In most cases, a high fever is present and in many other cases it is in excess of 38.3°C. In some patients, particularly those with significant coexisting diseases, fever may not be present and no symptoms of infection may occur. Risks factors for abscess or other infections include immunocompromised state, uncontrolled diabetes mellitus, history of chronic skin infections, history of methicillin-resistant Staphylococcus aureus infection or colonization, and wound breakdown at the surgery site. The diagnosis of abscess or disc infection requires a CT scan or surgical tissue sampling. The diagnosis of meningitis requires cerebral spinal fluid analysis [15].

Direct trauma to the spinal cord or nerve roots is a risk of needle and electrode placement. The use of general anesthesia or deep sedation appears to increase the risk of this type of complication [16]. Diagnosis of this complication can be made by a CT scan if the lead remains in place or by MRI if the lead has been removed. CT may miss nerve injury or subtle spinal cord insult. Electromyograms and nerve conduction studies may be helpful but may be normal for several weeks following injury [17]. In severe injuries, a steroid protocol for spinal injury should be initiated in the first few hours and a neurologist or neurosurgeon should be consulted.

The most common neurological insult from SCS is inadvertent dural puncture. In a landmark study, Kemler reported an 11% incidence of postdural puncture headache [18]. Risk factors for this complication include previous surgery at the site of the needle placement, obesity, spinal stenosis, scoliosis, calcified ligaments, and patient movement. Techniques that increase the risk of dural puncture include midline approach, angle of entry greater than 60°, and use of the retrograde approach. Dural puncture is more likely to occur in patients with previous surgery in the area of the spine that is being accessed, in patients with significant spinal disease, and in morbidly obese patients. Diagnosis includes direct vision of cerebral spinal fluid, positional headache, nausea, nystagmus, and tinnitus. Treatment includes hydration, caffeine, and rest. If the aforementioned treatments are unsuccessful, the use of a blood patch has been reported to be helpful [19]. The author cautions against the use of blood patch because of the risk of placing a potential culture medium around a foreign body. This technique should only be used in intractable cases of postdural puncture headache. In cases where a wet tap occurs, the physician may choose to abort the procedure or to continue and change the level and orientation of the needle. There does not appear to be any support in the literature for the best approach in these situations. The author continues the procedure at a level above the insult. In cases where a postdural puncture occurs, there appears to be no long-term sequelae and it does not appear to affect long-term outcomes.

Epidural fibrosis can occur with an indwelling lead in place. This problem may have a significant effect on the ability to program the system. In patients with surgical leads, the problem is usually self-limited because of the leads' unidirectional current delivery. In patients with percutaneous leads, the presence of fibrosis has varying effects. If the patient has one lead, or closely spaced leads that cover a finite area of the spinal cord or nerve, the leads may require surgical revision. In widely spaced dual lead octapolar systems, the leads may be reprogrammed to capture other fibers and to salvage a good outcome. In some settings, the amount of fibrosis does not appear to cause any change in the patient's condition and does not require treatment [20]. With specific nerve stimulation such as that with the retrograde or transforaminal approach, the presence of fibrosis may lead to the inability to program the system or even to perceive stimulation. Painful stimulation may also occur with fibrosis causing current transfer to the lateral nerve roots and spinal structures. In these settings, the author recommends a surgical lead revision. The issue of fibrosis may be less critical in the future as systems allow for more extensive coverage of the spine and nerve fibers.

The lead volume itself may create further narrowing if the patient's spine becomes stenotic at the level of implant [21]. In rare cases, this may require explanting of the device. Diagnosis is made by CT myelogram. A recent panel of experts discussed this issue in depth when considering the need for standard MRI prior to implanting a lead. The consensus was that an MRI is not required of the thoracic spine prior to a lumbar thoracic implant. An MRI was recommended in the cervical spine if the patient had a history of cervical spine disease (Levy R., personal communications, November 10, 2006).

Complications of Extraneuroaxial Tissues

Infection of the pocket or paraspinous electrodes can lead to the need for revision or removal of the system. The incidence of wound infection is generally quoted at 4.5%, but outliers do exist in some practices [15] (See Figure 1). The most common organisms for infection are Staphylococcus aureus, and other gram positive organisms. The implanting doctor should consider gram negative coverage in patients who have a colostomy or when implanting in the area of the sacral hiatus. The risk of infection can be reduced by careful prepping, draping, and gentle treatment of the tissues. The physician should limit the use of electrocautery near the superficial tissues, near the dermis, should consider bipolar heating when possible, and should close in two to three layers to better approximate the tissue edges. Wound closure can best be achieved with an absorbable suture in the deeper tissues and also in the subcuticular layers. When additional reinforcement of the wound is needed, a skin closure with stainless steel staples or nonabsorbable sutures such as nylon is recommended.

Figure 1

Superficial and deep pocket infections.

Diagnosis of infection includes erythema, rubor, and drainage of purulent material. Aspiration of the wound may reveal an abnormal gram stain and pathogens on cultures. Lab studies show an elevated white blood count, elevated sedimentation rates, and increased C-reactive protein. The differential diagnosis includes seroma or allergic reaction to the device.

Erosion of the skin by a lead or generator placed too superficially in the dermis can also lead to infection. In most cases, the generator should be at a depth of 2 cm or more. Telemetry and impedance testing can be done in the pocket prior to closure to assure the depth is not excessive. Weight loss may also lead to implanted leads, connectors or generators to become excessively superficial causing pain and possible tissue breakdown. In thin patients or in those with weight loss, the generator may require revision to a different location or to a tissue plane below the fascia (See Figure 2).

Figure 2

Erosion of lead anchor through skin.

Treatment of infections of the extraneural tissues can be with oral or intravenous antibiotics if the problem is superficial. Incision and drainage may be required if the generator or leads are involved, and removal of the device may be required. The device may be replaced in 12 weeks if the infection is eliminated. It is important to consult with an infectious disease practitioner prior to reimplant for advice on antibiotic coverage.

In a red, swollen wound with minimal fever or change in lab studies, a seroma should be considered (See Figure 3). A seroma is a noninfectious process that involves the seepage of serum from the tissues of the pocket into the area surrounding the generator. This may be caused by excessive tissue trauma, such as aggressive sharp dissection, excessive use of cautery, or forceful blunt retraction. Diagnosis can be confirmed by aspiration of a straw-colored fluid that is negative on microscopic exam for bacteria and subsequent culture. Diagnosis can also be confirmed by surgical exploration and drainage, with culture and fluid analysis. Treatment can be by pressure applied to the tissue, needle aspiration, or by surgical incision and drainage. If the physician chooses to aspirate the seroma, careful attention should be paid to sterile technique. Aspiration can lead to introduction of infection and the risk to benefit ration should be considered. Open incision and drainage is a treatment option if the seroma does not resolve. High pressure, high volume antibiotic irrigation should be considered at the time of surgical exploration, to dilute any possible contaminants in the tissue.

Figure 3

(A) Seroma; (B) aspiration of seroma.

A hematoma can occur at the generator site from an acute arterial bleed or a slow venous leak. It is critical to inspect the wound prior to closure for this problem. When using local anesthetics with epinephrine, the risk of acute bleeding is reduced because of vasoconstriction, but the risk of subacute bleeding is increased because the epinephrine may lose its effect after wound closure. This problem has led some to discontinue the use of epinephrine or to make the pocket prior to lead placement to allow for wound inspection prior to closure. Treatment is by compression and observation. If the problem does not resolve in a reasonable time, an incision and drainage must be performed [21] (See Figure 4). If a hematoma goes untreated, it can lead to wound dehiscence and wound infection with loss of the system.

Figure 4

Hematoma of pocket with dehiscences of wound.

Pain at the generator site, lead site, or connectors, can lead to poor patient satisfaction. Postoperative pain can occur in patients with spinal cord stimulators and connectors. Pain can be treated by conservative measures such as lidoderm patches, injections of neuroma or cushioning of hardware sites. If the problem does not resolve, surgical revision may be required. In thin patients this may require moving the generator below the fascia or muscle belly.

Complications Involving the Device

Some authors have reported uncharacteristically high complication rates related to the device. Taylor had a device complication rate of 43%, which was elevated by the inclusion of minor issues such as pain at the pocket site [22]. Alo reported a much lower number of 6% [23]. Cameron reported the following complication rates based on reviewed studies: 1) lead migration 13.2%; 2) lead breakage 9.1%; 3) infection 3.4%; 4) hardware malfunction 2.9%; and 5) unwanted stimulation 2.4% [24]. Table 2 shows the occurrence of these problems.

View this table:
Table 2

Summary of top SCS-related complications

ComplicationNo. of EventsTotal No. of CasesIncidence %
Lead migration361275313.2
Lead breakage2502753 9.1
Infection1002972 3.4
Hardware malfunction 802753 2.9
Unwanted stimulation 652753 2.4
  • Adapted from Cameron 2004 [24].

  • SCS = spinal cord stimulation.

The most frequently seen issue is loss of stimulation to the desired area. Causes of this complication include epidural fibrosis as noted above, lead migration, or disease progression. Diagnosis is made by plain films, computer analysis of impedance, and physical exam. Initial treatment is by reprogramming of the device. Other options include surgical lead revision, or revision to a more complicated system [25–27].

Lead migration is another complication that should be considered with device failure. Diagnosis is made by plain film comparison to initial implant studies (See Figure 5). Lead migration can occur, secondary to poor anchoring technique, poor angle of entry, or excessive patient movement. Prevention of this problem may include the use of a 30° angle for needle entry, placement of the lead at a minimum of two vertebral bodies, anchoring of the system to the spinal ligaments, and the presence of a strain relief loop at the site of lead entry to the ligament, and at the generator site. Treatment is reprogramming, and if there is a lack of recapture of appropriate paresthesia, surgical revision by either surgical or percutaneous approach. If the migration creates pain of a nerve root or ligamentum flavum, revision is definitely indicated. The need for revision has decreased as the use of multi-channel leads has become more common [27].

Figure 5

(A) Pre-lead migration; (B) lead migration.

Painful stimulation can be a result of a current leak or lead fracture. Diagnosis is made by high impedance on computer analysis, or by plain films showing the problem. The majority of lead fractures occur in surgical leads placed the cervical spine or in the retrograde approach. In order to prevent fracture, strain relief loops are needed The leads should be placed in an orientation to relieve stress on the materials. In some instances, trauma causes the leads to fracture, which can in turn, cause system failure. Treatment is by surgical revision and by adding new technology to reduce the impact of future fractures.

In the past few years, a new complication has developed due to recharging of generators. In rare cases, a burn of the skin can occur due to overheating. Treatment includes immediate treatment of the burn, consultation of a plastic surgeon, and eventual revision of the device. Consideration should be given to changing the manufacturer of the device that is implanted in the deeper tissues or to a system that does not require recharging. Rechargeable batteries may also lead to the problem of elderly or mentally challenged patients being unable to understand how to recharge the system. The treatment of this problem is to simplify the programming or to consider revision to a conventional internally programmable generator.


The process of implanting and caring for a patient with a SCS system is complicated. The risks of the procedure are small compared with repeat back surgery, and outcomes may be more effective compared with other chronic pain therapies as measured by patient satisfaction and cost-effectiveness, [28–30]. The implanting doctor should be vigilant regarding complication prevention, identification, and treatment of adverse outcomes. The use of consulting doctors should be considered to reduce, treat, and rehabilitate patients who have had complications. By careful attention to detail, the implanting doctor can reduce the incidence of bad outcomes, enhance the effectiveness of the procedure, and improve patient outcomes.


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