Christian Scherer

Spinal cord stimulation for refractory angina in patients implanted with cardioverter defibrillators: five case reports.

Patients implanted with a cardioverter defibrillator (ICD) who are suffering from refractory angina pectoris could benefit from spinal cord stimulation (SCS) due to the well-documented pain relieving effect. However, the combined treatment remains controversial. The aim of the study is to report successful long-term treatment with SCS in five patients implanted with cardioverter defibrillators. The combined treatments with ICD and thoracic epidural electrical stimulation were used in five patients with refractory angina pectoris. During the procedure of the implantation, testing with the maximal tolerable level of stimulation was carried out to exclude inference with the ICD. The following treatment with SCS has in all cases been successful, with significant pain relief and improved quality of life. There were no incidences of inappropriate defibrillator shocks. Spinal cord stimulation for refractory angina pectoris can be performed in patients implanted with cardioverter defibrillators without interference. However, individual testing during implantation or re-programming the devices is mandatory in order to assess optimal safety in each patient.

Management of Spinal Cord Stimulators in Patients with Implantable Cardioverter‐Defibrillators

We report a case of spinal cord stimulation (neurostimulation) as treatment of angina pectoris pain in a patient with an implantable cardioverter‐defibrillator. The precautions taken to avoid inhibition of the demand pace function and avoid activation of the shock function by the neurostimulation are discussed.

Spinal cord stimulation has proven benefit on pain and quality of life in patients with angina pectoris when less invasive therapies have failed.

Background.  Since 1988, spinal cord stimulation (SCS) has been used at Odense University Hospital for patients with refractory angina pectoris. The aim of our prospective study was to evaluate the long‐term effects of SCS on pain, activities of daily living (ADLs), quality of life (QOL), sleep hygiene, and physical functioning for patients with angina pectoris.

412 DYSAESTHESIC PAIN AND BURNING SKIN SENSATIONS AS ADVERSE EFFECTS TO SPINAL CORD STIMULATOR IMPLANTATION FOR TREATMENT OF ANGINA PECTORIS

Background and aim. Spinal cord stimulation (SCS) has become an established pain treatment for patients with angina pectoris or neuropathic pain. However, several reports indicate that the implantation of SCS devices itself may cause chronic pain conditions. Five male patients with known refractory angina pectoris developed painful dysaesthesia or burning skin sensations after implantation or reimplantation of SCS devices. The pain symptoms were constant and not related to the electrical stimulation. Two patients had painful dysaesthesia and burning skin sensations located to their faces, arms and genitals. Two patients reported pain located to the extension leads. One patient slowly developed painful dysaesthesia in both hands and feet. Four of the patients had their SCS devices removed. Further examinations showed negative patch tests to all product ingredient samples and no signs of infection. Methods. Interviews with all five patients were made. Results. Two patients reported that after the spinal cord stimulator was removed, their symptoms slowly decreased in intensity and disappeared. Two patients had still pain and burning skin sensations three years after the SCS devices had been removed. In one case, the symptoms were concluded to be due to diabetic neuropathy and not SCS. The patient that refused to have his spinal cord stimulator removed has still painful dysaesthesia more than three years after the implantation of the SCS devices. Conclusion. It seems likely that in four of the five case reports, the pain and burning skin sensations reported by the patients were due to implantation of SCS devices.

597 PARAESTHESIA AND BURNING SKIN SENSATION LIKELY DUE TO IMPLANTATION OF SPINAL CORD STIMULATION DEVICES FOR TREATMENT OF ANGINA PECTORIS

Spinal cord stimulation (SCS) has become an established pain treatment for patients with angina pectoris not suitable candidates for coronary bypass grafting or intraarterial invasive technique. The implants are well tolerated, and side effects are mostly lead migration, discomfort due to the pulse generator or pain located to the fixation of the lead. The abstract describes five case reports with unusual neurological complications likely due to spinal cord stimulation devices. The patients (age 49–74 years) developed widespread constant paraesthesia or burning sensations weeks after implantation of SCS devices. The symptoms were constant and not related to activation of the pulse generator. Four of the patients had the devices explanted and their symptoms decreased in intensity during the nest months. None of the patients had a history of previous skin disease, known contact allergy or dermatitis related to the stimulation device. Four of the patients agreed to an allergological investigation to clarify if an allergic mechanism could be rendered probable. The four patients were patch tested according tested according to standard procedure with the European Standard Series supplemented with a series of epoxy and isocyanate chemicals known to be potential contact allergens, and samples of all stimulation device components supplied by the product manufacturer. None of the four patients had any current dermatitis and they all had negative patch tests to all test chemicals and product ingredient samples. In the four patients examined, discomfort due to SCS could not be related to an allergic reaction mechanism.

596 THE SIGNIFICANCE OF CONTINUES STIMULATION WHEN TREATING INTRACTABLE ANGINA PECTORIS WITH SCS

Introduction: Botulinum toxin acts at the neuromuscular junction inhibiting the release of acetylcholine by acting on proteins involved in neurotransmitter release. Blocks of the cholinergic autonomic stellate ganglion using local anaesthetic are frequently used for the treatment of neuropathic pain involving the face and upper limbs but duration of effect is limited to 1−4 months. Can Botulinum A produce prolonged analgesia through action at cholinergic autonomic ganglia? Methods and Results: Case History: Here we present a case study where a patient obtained dramatic and prolonged improvement in longstanding facial pain and importantly allodynia following a stellate ganglion block using BTA alone, having previously undergone a series of diagnostic stellate ganglion blocks using local anaesthetic with benefit of limited duration. The patient’s complex pain problem followed a radical neck dissection. The patient reported a 90% reduction in pain and importantly had complete resolution of allodynia for twelve months. He had barely been able to touch his face and could not shave prior to the injection. Conclusion: Our convincing case study is difficult to ascribe to an effect at the neuromuscular junction. We believe that this case report demonstrates that botulinum toxin A acts as an analgesic agent when injected at the stellate ganglion and that it appears to do so independently of its effects at the neuromuscular junction. Reports of safe, effective use of a product are an important precursor to formal clinical trials.

843 CAN RECHARGEABLE NEUROSTIMULATORS PLAY A ROLE IN SPINAL CORD STIMULATION THERAPY IN PATIENTS WITH REFRACTORY ANGINA PECTORIS

Background and Aims: Laser Doppler flowmetry (LDF) and venous occlusion plethysmography are techniques frequently used in TENS studies to measure blood flow changes in skin and volume changes in a limb segment, respectively. However, the effect of TENS on blood flow locally in human muscle has not previously been investigated. The primary aim of the present study was to investigate effects of TENS on blood flow in the trapezius muscle by using a new application of photoplethysmography (PPG), i.e. a non-invasive technique. Methods: Skin and muscle blood flow were monitored non-invasively for 30 min during and following 15 min of low (2Hz) and high (80Hz) frequency TENS of high intensity and sub-liminal (0.5mA) TENS (used as control) in 30 healthy females. Results: The blood flow in the trapezius muscle increased significantly with low frequency TENS, whereas no increase existed with high frequency or sub-liminal TENS. Blood flow increase with Lo TENS was significantly more increased than Sub TENS until 3 min post-stimulation. Skin blood flow did not increase significantly during any of the TENS interventions. Conclusions: Low frequency TENS of high intensity resulting in visible muscle contractions induced an instant and significant blood flow increase in the trapezius muscle. However, the stimulation might have been too strong to cause an increase in skin blood flow. The new application of PPG is a simple and pain-free technique for non-invasive and simultaneous measurements of muscle and skin blood flow changes.

Possible Stabilization of Spinal Cord Stimulation Treatment in Refractory Angina Pectoris by Implantation of a Second Electrode: Case Reports

Patients with refractory angina pectoris usually exhaust conventional treatment of ischemic heart disease. They frequently need opioids and still have angina pectoris despite earlier coronary artery bypass grafting (CABG) or percutaneous coronary intervention (PCI). In those cases, treatment strategies including neuromodulation techniques such as transcutaneous electrical neurostimulation (TENS) or spinal cord stimulation (SCS) often are successful. Covering the pain area with electrically induced paraesthesia leads to a reduction in angina incidence, reduced opioid and nitrate consumption, better results under stress test, and better quality of life. A rare complication in treatment of refractory angina pectoris with SCS is repeated electrode displacement. We report three cases where the problem was solved with the implantation of a dual electrode system. After a period with TENS, patients suffering from refractory angina pectoris are normally treated with implantation of a single electrode SCS‐system. Presently over 130 devices have been implanted for this indication at our hospital. In three patients, repeated electrode displacement occurred, and despite the attempt to replace the electrode, it was impossible to provoke sufficient paraesthesia in the pain area. These patients were offered the implantation of a dual electrode system where two electrodes are placed in the epidural space. With the dual electrode system, good and stable stimulation was achieved, provoking appropriate paraesthesia. This suggests that two electrodes implanted in the epidural space may stabilize each other mechanically. On the other hand the variety of program adjustments is enlarged, due to the additional poles on the second electrode. On the basis of these case reports, we suggest that implantation of a dual electrode SCS‐device might be the solution in case of repeated displacement of a single SCS‐electrode.