Methods:  In a prospective study, we treated 74 CRPS-1 patients with a mean disease duration of 17 weeks with standard therapy consisting of physical therapy, topical dimethyl sulfoxide, analgesics, transcutaneous stimulation, and sympathetic blockade. Patients who did not respond to standard therapy were offered a treatment with SCS. In these patients, we investigated the impact on pain, quality of life, and function.

Results:  Out of these 74 patients treated with standard therapy, six patients were included for early SCS treatment. The overall mean pain relief after one year was 35%. The mental component of the Short Form 36 improved; however, there was no effect on the physical component. None of the SCS treated patients showed a clear improvement in functional outcome.

Discussion:  We conclude that the feasibility of performing a randomized controlled trial on early SCS therapy in CRPS-1 is low because of the good disease improvement with standard therapy in the first year after onset. This study raises questions about the need to use SCS early in the course of CRPS-1 because of the probable lack of additional benefit compared with SCS in chronic CRPS-1.

Materials and Methods:  A 57-year-old man had intractable pain because of multiple intradural spinal explorations for tethered cord release. His pain was effectively treated with intrathecal morphine via an IDDS. Five months after the implantation, the patient developed return of the original pain more than two weeks after intrapleural migration of the intrathecal catheter.

Results:  The migration was documented by computed tomography, and repositioning of the catheter rendered the patient comfortable. The gradual onset of pain may have been due to decreasing delivery of drug to the cerebrospinal fluid as the catheter tip migrated further away from the dura. To our knowledge, this complication has not been reported in the literature.

Conclusion:  Physicians and nursing staff that place and manage an IDDS should be aware of this complication.

Materials and Methods:  Forty patients with chronic, intractable pain implanted with both SCS and PSFS leads were enrolled in a retrospective data collection study. Pre-implant data (demographics, pain levels, pain location, and medication use) and post-implant data (pain levels, medication use, and device programming reports) were compared to measure short- and long-term improvements in pain for a period of approximately six months. Device system use and parameter data were collected.

Results:  The majority of patients experienced immediate and short-term pain relief and reduction in oral pain medications as a result of combination SCS/PSFS therapy. The improvements were maintained for some, but not all patients by six months. Patients cycled through multiple programs over follow-up; the use of triangular stimulation was consistent over time, and by six months, patients preferred this program over others. Limitations of the retrospective chart review included missing data and variable follow-up times, and may have made determinations of long-term efficacy difficult.

Conclusions:  This study demonstrates that combination SCS and PSFS therapy is potentially a beneficial treatment option for reducing pain levels and oral pain medication compared with baseline in previously resistive chronic pain patients. There is a need for further study of this therapy in a greater number of subjects and in a prospective, controlled setting. In the author's general experience, triangular stimulation is very effective for treating isolated low back pain, because it covers larger topographic areas of the lower back than flow or field stimulation. An investigational device exemption study will be necessary for subcutaneous field stimulation indicated for focal isolated pain to be adequately investigated and utilized by physicians in the future.

Materials and Methods:  25 patients who underwent bilateral, infraclavicular subcutaneous IPG placement for DBS and 15 patients who had bilateral, transaxillary subpectoral IPG placement were investigated.

Results:  The differences in cosmetic satisfaction and discomfort between the two groups were significant. The cosmetic satisfaction was higher and discomfort was less in the subpectoral IPG implantation group (p = 0.002 and p = 0.000). However, more time was needed for IPG implantation, and the postoperative pain was more severe after subpectoral IPG implantation (p = 0.002 and p = 0.000). There was no difference in cosmetic satisfaction according to sex (p = 0.907). There was one transient intercostobrachial nerve injury in the subpectoral IPG implantation group and two infections which needed removal of one side of the DBS hardware in the infraclavicular IPG implantation group.

Conclusions:  These results demonstrated that subpectoral transaxillary IPG implantation can provide better cosmetic satisfaction in patients undergoing DBS, with less discomfort and morbidity related to erosion and infection.

Material and Methods:  A 30-year-old man with a four-year history of chronic testicular pain following scrotal hydrocele surgery had two percutaneous leads implanted in his groin and low-frequency stimulation of the cutaneous branch of the ilioinguinal and genital branch of the genitofemoral nerves.

Result:  At seven-month follow-up, the pain intensity had declined from 9/10 to 2/10 on the numeric rating scale.

Conclusion:  We report the successful implantation of an ilioinguinal and genitofemoral nerve stimulator for sustained suppression of intractable neuropathic testicular pain.

Materials and Methods:  We describe two minimally invasive revision techniques. One uses a 14-gauge Tuohy needle converted to a slotted needle. The other uses a standard Tuohy needle inserted subcutaneously into the anchor site along the desired course of the lead.

Results:  Both techniques allow replacement of a migrated occipital nerve stimulator lead while eliminating the need to access connector or battery sites with multiple incisions.

Conclusions:  When migration occurs, the techniques described can simplify lead revision while minimizing the invasiveness of the procedure.

Methods:  Keywords applicable to spinal cord stimulation therapy, including paresthesia perception, spinal cord position, lead impedance, and sensor technologies, were searched in the PubMed, EMBASE, and Cochrane Library databases. Literature analysis, combined with extensive clinical experience with spinal cord stimulation therapy, forms the basis of this review.

Results:  Fluctuations in paresthesia perception are largely caused by variation in the distance between the fixed electrodes and the spinal cord consequent to patient movement. Patients employ multiple strategies with varying success to manage position-related fluctuations in stimulation perception, which may result in suboptimum therapy delivery.

Conclusions:  A new type of spinal cord stimulation system that incorporates accelerometer technology to automatically adjust stimulation amplitude based on patient position may better meet patient analgesic needs and is in early clinical application.

Methods:  This is an observational study on nine patients with rINS. All patients had initially received non-rechargeable INS with established efficacy of their deep brain stimulation system for either dystonia or pain. Patient satisfaction and efficacy with their rINS were established by completion of a questionnaire, a quality of life assessment (SF-36), and calculation of the total electrical energy delivered (TEED) by the rINS.

Results:  A reduction in efficacy of their rINS was noticed in 22% of patients. In 78% of patients, there was a problem with recharging their rINS because of poor contact. Two patients (22%) felt that recharging the rINS interfered with their lives and it was a daily reminder that they had a deep brain stimulator system in situ. Eight out of nine patients (89%), however, would recommend to other patients to have an rINS.

Conclusion:  Most patients were happy with their rechargeable internal neural stimulator. A reduction in efficacy was noticed in 22% of patients, which is similar to the proportion of patients noticing a reduction in efficacy when replacing with a non-rechargeable system. Thus, all patients require close monitoring post-replacement of rINS, in case possible adjustment of parameters is required.

Materials and Methods:  Patients with FBSS being eligible for SCS were enrolled in the study, and a hybrid lead was placed surgically. Outcome measures included pain scores for low back and leg pain assessed by visual analog scale (VAS), pain medication, and patient satisfaction. These scores were assessed before and at regular intervals after implantation.

Results:  It was shown that a single hybrid lead, generally positioned over the physiological midline of the spinal cord, is capable of alleviating both low back and leg pain in patients with FBSS. Forty-five subjects were eligible for SCS and received trial stimulation. Forty-two of them had a successful trial period and were converted to a permanent system. Their average VAS score at baseline was 8.0 for lower limb pain and 7.5 for low back pain. After six months of SCS, these average VAS scores were reduced to 3.2 and 3.5, respectively, and also pain medication was reduced significantly.

Conclusion:  SCS with a hybrid lead in subjects with FBSS is safe, and causes significant pain relief in both the low back and the lower limbs.

Methods:  Six patients with intractable low back and leg pain following extensive lumbar and thoracic surgeries, up to at least the T10 level, underwent a stimulation trial with one caudal lead and one subcutaneous lead in order to achieve SPN.

Results:  In five cases, the trial was successful with coverage of the pain area and at least satisfactory pain relief. All six patients were implanted with a paddle lead(s) and a subcutaneous lead using SPN with good pain control.

Conclusion:  SPN with a caudal lead appears to be a viable option for SCS trial in patients with no possibilities for conventional trial lead placement.

Materials and Methods:  A repeated measures parallel group study on healthy human volunteers randomized to receive strong non-painful TENS or non-invasive interactive neurostimulation for 21 min on the forearm (N= 10/group). Pressure algometry was used to determine blunt pressure pain threshold at baseline, 10, and 20 min during stimulation, and 5 min post stimulation.

Results:  Low impedance sites were found in half of the participants receiving non-invasive interactive neurostimulation. ANOVA found no effects for intervention (p= 0.923), time × intervention interaction (p= 0.21), or time (p= 0.094).

Conclusions:  Given the limited power of this study, we show that there were no significant differences in hypoalgesia between non-invasive interactive neurostimulation and TENS. Unlike our previous studies we also failed to detect a change pain threshold during TENS. Nevertheless, our findings can be used to inform the design of an appropriately powered study on pain patients.

Study Design:  Case series.

Materials and Methods:  FBSS patients with chronic limb and/or low back pain whose conventional therapies had failed received a combination of SCS (8-contact Octad lead) and/or SubQ (4-contact Quad Plus lead(s)). Initially leads were placed in the epidural space for SCS for a trial stimulation to assess response to suppression of limb and low back pain. Where SCS alone was insufficient in treating lower back pain, leads were placed superficially in the subcutaneous tissue of the lower back, directly in the middle of the pain area. A pulse generator was implanted if patients reported more than 50% pain relief during the trial period. Pain intensity for limb and lower back pain was scored separately, using visual analog scale (VAS). Pain and Quebec Back Pain Disability Scale (QBPDS) after 12-month treatment were compared with pain and QBPDS at baseline.

Results:  Eleven FBSS patients, five male and six female (age: 51 ± 8 years; mean ± SD), in whom SCS alone was insufficient in treating lower back pain, were included. In nine cases, SubQ was used in combination with SCS to treat chronic lower back and lower extremity pain. In two cases only SubQ was used to treat lower back pain. SCS significantly reduced limb pain after 12 months (VAS_bl: 62 ± 14 vs. VAS_12m: 20 ± 11; p= 0.001, N= 8). SubQ stimulation significantly reduced low back pain after 12 months (VAS_bl: 62 ± 13.0 vs. VAS_12m: 32 ± 16; p= 0.0002, N= 10). Overall pain medication was reduced by more than 70%. QBPDS improved from 61 ± 15 to 49 ± 12 (p= 0.046, N= 10). Furthermore, we observed that two patients returned to work.

Conclusion:  SubQ may be an effective additional treatment for chronic low back pain in patients with FBSS for whom SCS alone is insufficient in alleviating their pain symptoms.

Methods:  A retrospective review was conducted of consecutive patients evaluated from August 2009 to December 2010 who had undergone trial of SQ PNS with inter-lead stimulation for axial spine pain. Patients proceeding to implant were followed postoperatively with routine clinical visits and a survey form at last follow-up. Ultrasound was used intraoperatively to ensure placement of electrodes at the appropriate depth in patients with larger body mass index. Primary outcome was patient-reported pain relief at last follow-up. Literature review was conducted by searching MEDLINE (1948–present) and through an unstructured review by the authors.

Results:  Ten patients underwent trial of SQ PNS and six proceeded to permanent implantation. Fifty percent (3/6) of implanted patients preferred neurostimulation programming that included inter-lead stimulation (“cross-talk”). Average duration of postoperative follow-up was 4.5 months (range 2–9 months). Average patient-reported pain relief at last follow-up was 45% (range 20–80%). One patient required re-operation for migration. Patients not proceeding to implant had paresthesia coverage but no analgesia.

Conclusion:  SQ PNS is a promising therapy for axial neck and back pain based on a small cohort of patients. Ultrasound was useful to assist with electrode placement at the most appropriate depth beneath the skin. While inter-lead stimulation has been preferred by patients in published reports, we did not find it clearly influenced pain relief. Future investigations should include a randomized, controlled study design, as well as defined implantation technique and neurostimulator programming algorithms.

Materials and Methods:  This multicenter, prospective, open-label study included medical centers experienced in SCS therapy, carried out in 13 physicians in seven centers. We recruited 55 patients with complex regional pain syndrome, failed back surgery syndrome, or peripheral vascular disease. Neurostimulators were implanted in 34 patients found to respond to SCS in a preliminary test, who were then followed for six months. Thirty-four patients scored their pain on a visual analog scale (VAS) and completed the EuroQol-5D questionnaire before and after test stimulation and after one and six months.

Results:  During test stimulation, the mean VAS and quality of life (QOL) scores improved from 74.0 to 23.4 and from 0.430 to 0.664, respectively, in the 34 patients. At six months, the mean VAS score was 29.7 in 29 patients and the mean QOL score was 0.661 in 31 patients.

Conclusion:  SCS may improve pain management and QOL.

Materials and Methods:  Data from 61 patients (of 71 eligible patients) were collected by means of a telephone interview. These data included the pattern of stimulation (intermittent or continuous), the intensity of stimulation with regard to threshold, the mean, maximal, and minimal pain strength on a numerical rating scale with and without stimulation, the average duration and number of daily stimulation intervals, the average duration of the pain-relieving effect after switching off the impulse generator, the pain medication intake, the extent of paresthesia coverage, unpleasant side effects, and patient satisfaction.

Results:  The average improvement in pain score following SCS was 3.10 (50.61%). Twenty-four patients (39.3%) performed continuous stimulation, and 37 patients (60.7%) performed intermittent stimulation. Patients who performed continuous stimulation had significantly shorter pain-free intervals following the cessation of stimulation. These patients also showed a tendency toward higher pain scores with and without stimulation, which was not statistically significant. There were no significant differences in pain scores, duration of pain relief, and usage of the stimulation system between patients with different diagnoses and lead locations.

Conclusion:  Our data showed an equal effectiveness of SCS in the intermittent and in the continuous stimulation mode. The duration of the post-SCS pain-free interval may be predictive for the choice of the most effective individual stimulation pattern and deserves further investigation.

Materials and Methods:  After Investigational Review Board clearance, patients consented to data collection in a prospective fashion regarding the use of a new percutaneous epidural introducer (Epiducer, St. Jude Neurological, Minneapolis, MN, USA) to place paddle leads and complex lead arrays. The patients underwent education regarding expectations and risks of the procedure consistent with our normal preoperative period. Patients underwent preoperative anesthesia screening and proper testing as outlined by the Joint Commission on Hospital Accreditation, and were given the opportunity to ask questions concerning the procedure. Once the patient wished to move forward, they were consented using the approved case reporting form and followed during the course of their care.

The initial cases were performed in West Virginia with subsequent cases following at the other centers involved in this analysis.

The outcomes of this analysis focused on three areas:

• 1
  The technical success in placing the percutaneous sheath. This included the ability to successfully complete:

  • • 
    epidural access with a 14-gauge Tuohy needle
  • • 
    ability to place a styleted guidewire
  • • 
    ability to introduce the introduction system over the wire into the epidural space
  • • 
    ability to remove the guidewire and introduction tip leaving the 10-gauge sheath intact
• 2
  The ability to place the desired lead or leads into the epidural space via the percutaneous introduction sheath.
• 3
  The presence of any major adverse event which were defined as:

  • • 
    nerve injury
  • • 
    paraplegia
  • • 
    worsening of baseline pain
  • • 
    epidural hematoma
  • • 
    epidural infection
  • • 
    dural tear
  • • 
    dural rent
  • • 
    retained device that could not be removed

This information was carefully recorded for each implant, and summarized in this communication.

Results:  During the initial 30 days of the evaluation period, 43 epidural introduction systems were attempted in 38 patients. In patients in whom more than one paddle lead was placed, the system required the reinsertion of the guidewire through the Epiducer, removal of the Epiducer, and rewiring over the guidewire. This is necessary because the diameter of a paddle lead does not allow two or three leads to be placed without rewiring the system. The success of placement was 42/43, with inability to access the epidural space in one patient in whom ligamentum flavum hypertrophy was present on the preoperative imaging study. In all patients, the system was placed at the L1–L2 level, or lower, based on the Food and Drug Administration labeling.

The total numbers of leads placed were 75, with both paddle and percutaneous arrays implanted successfully.

There were no adverse events during this prospective surveillance evaluation.

Ten patients complained of soreness at the entry site and post-procedure stiffness. These complaints were treated with ice, rest, and analgesics and resolved without incident.

Conclusion:  This paper describes the initial US cases of the placement of a paddle lead via a minimally invasive percutaneous method, as well as complex cylindrical arrays with a single needle entry to the epidural space. The device functioned successfully and presented a safe option for placing paddle leads and complex arrays.

Case Reports:  Three patients treated chronically with intrathecal clonidine presented with clonidine overdose due to inadvertent extravasation during the refilling procedure. All patients experienced loss of consciousness and severe systemic hypertension that required aggressive parenteral treatment.

Discussion:  Clonidine is an alpha-2 agonist with a nearly 100% bioavailability after oral or rectal administration. With high plasma concentration secondary to massive systemic overdose, the specificity for the alpha-2 receptor is lost and an alpha-1 agonist activity predominates and causes marked hypertension. Management of clonidine overdose consists of supportive therapy guided by signs and symptoms.

Conclusion:  Inadvertent injection into the subcutaneous pocket rather than the reservoir is rare but very dangerous as the drug cannot be retrieved and massive doses are involved. Signs and symptoms of systemic overdose with drugs commonly used in implanted drugs delivery system should be well known to ensure early diagnosis and treatment.

Methods:  The clinical course of a 56-year-old woman was reviewed, including past imaging studies.

Results:  The patient presented with acute lower extremity paresis secondary to air trapped within an arachnoid cyst thought to be due to long-term use of IT morphine and an undiagnosed CSF loculation. She rapidly recovered after surgical decompression.

Discussion:  Symptomatic pneumorachis is rare. In this case, because of radiographically impressive compression and severe deficit, we felt that the trapped air was equivalent to a mass lesion and treated it aggressively. The arachnoid cyst was near the level of the catheter tip prior to revision, and we have retrospectively inferred a causal relationship.

Materials and Methods:  We report a 78-year-old man with severe spasticity and pain in the lumbar region and both lower extremities because of ossification of the posterior longitudinal ligament, spinal canal stenosis, and cerebral infarction. He was severely disabled and bedridden. Earlier surgical interventions (spinal cord stimulation and deep brain stimulation) had failed.

Results:  He underwent a screening test for intrathecal baclofen (ITB) therapy. The intrathecal injection of 50 µg baclofen severely aggravated his spasticity and pain and concomitantly elicited myoclonic-like involuntary movements in both lower extremities. Although 25 µg baclofen produced similar results, overt improvements were obtained with 12.5 µg, and he underwent implantation of an ITB pump. His spasticity and pain responded to initial daily doses of 12.5 µg. To obtain further improvements, we gradually increased the daily dose to 40 µg; however, this severely increased his spasticity and pain in both lower extremities and concomitantly elicited myoclonic-like involuntary movements. He is being maintained on a daily dose of 20 µg/day.

Conclusions:  We suggest that in patients who experience symptom aggravation at increased ITB doses, potential causative factors and ITB system malfunction should first be ruled out, and consideration should then be given to decreasing the ITB dose.

Materials and Methods:  We used a modified version of the rubber hand illusion presented to 30 able-bodied participants (16 women, 14 men) to convey TENS paresthesia to an artificial hand. TENS electrodes were located over superficial radial nerve on the lateral aspect of the right forearm (1 cm proximal to the wrist), which was hidden from view. TENS intensity was increased to a strong non-painful TENS sensation (electrical paresthesia) was felt beneath the electrodes and projecting into the fingers of the hand. The electrical characteristics of TENS were asymmetric biphasic electrical pulsed waves, continuous pulse pattern, 120 Hz pulse frequency (rate), and 80 µs pulse duration (width).

Results:  Participants reported significantly higher intensities of the rubber hand illusion during the two TENS conditions (mean = 5.8, standard deviation = 1.9) compared with the two non-TENS conditions (mean = 4.9, standard deviation = 1.7), p < 0.0005.

Conclusions:  Our findings provide initial evidence that TENS paresthesia can be projected into an artificial limb, and this can enhance the sense of perceptual embodiment of an artificial hand. Further exploratory studies involving an amputee population are warranted.

Materials and Methods:  Visual and auditory feedback cues were generated by a wearable device, driven by inertial sensors. Ten randomly selected patients with gait disorders due to cerebral palsy and seven age-matched healthy individuals trained with visual feedback cues, while ten patients and eight age-matched healthy individuals trained with auditory feedback cues. Baseline performance (walking speed and stride length along a 10-m straight track) was measured before device use. Following 20-min training with the device and a 20-min break, performance without the device was measured again and compared with the baseline performance.

Results:  For the patients who trained with visual feedback, the average improvement was 21.70% ± 36.06% in the walking speed and 8.72% ± 9.47% in the stride length. For the patients who trained with auditory feedback, the average improvement was 25.43% ± 28.65% in the walking speed and 13.58% ± 13.10% in the stride length. For the healthy individuals who trained with visual feedback, the average improvement was −2.41% ± 9.54% in the walking speed and −2.84% ± 10.11% in the stride length. For the healthy individuals who trained with auditory feedback, the average improvement was 0.01% ± 7.73% in the walking speed and −2.03% ± 6.15% in the stride length.

Conclusions:  Training with visual and auditory feedback cues can improve gait parameters in patients with gait disorders due to cerebral palsy. This was contrasted by no improvement in age-matched healthy individuals.