Spinal cord stimulation in peripheral vascular disease

Spinal cord stimulation in the treatment of acute and chronic vasculitis: clinical discussion and synopsis of the literature

OBJECTIVES

  Spinal cord stimulation (SCS) has been widely noted as a treatment for ischemic pain secondary to peripheral vascular disease, but evidence in the vasculitis disease state is lacking. In this paper we present two cases that exemplify the potential of SCS in this unique population.

MATERIAL AND METHODS

  Two case studies involving patients with the conditions noted including initial findings, treatment protocol, and results documented throughout the treatment regimen. A comprehensive review of the critical literature also was performed.

RESULTS

  Both patients showed marked improvement with SCS. Pain scores improved dramatically, with a major improvement in disease symptom and quality of life.

CONCLUSIONS

  Based on literature and our results, SCS is an effective and safe therapy for patients with therapeutically refractory vasculitis.

Spinal cord stimulation for ischemic heart disease and peripheral vascular disease

Ischemic disease (ID) is now an important indication for electrical neuromodulation (NM), particularly in chronic pain conditions. NM is defined as a therapeutic modality that aims to restore functions of the nervous system or modulate neural structures involved in the dysfunction of organ systems. One of the NM methods used is chronic electrical stimulation of the spinal cord (spinal cord stimulation: SCS). SCS in ID, as applied to ischemic heart disease (IHD) and peripheral vascular disease (PVD), started in Europe in the 1970s and 1980s, respectively. Patients with ID are eligible for SCS when they experience disabling pain, resulting from ischaemia. This pain should be considered therapeutically refractory to standard treatment intended to decrease metabolic demand or following revascularization procedures. Several studies have demonstrated the beneficial effect of SCS on IHD and PVD by improving the quality of life of this group of severely disabled patients, without adversely influencing mortality and morbidity. SCS used as additional treatment for IHD reduces angina pectoris (AP) in its frequency and intensity, increases exercise capacity, and does not seem to mask the warning signs of a myocardial infarction. Besides the analgesic effect, different studies have demonstrated an anti-ischemic effect, as expressed by different cardiac indices such as exercise duration, ambulatory ECG recording, coronary flow measurements, and PET scans. SCS can be considered as an alternative to open heart bypass grafting (CABG) for patients at high risk from surgical procedures. Moreover, SCS appears to be more efficacious than transcutaneous electrical nerve stimulation (TENS). The SCS implantation technique is relatively simple: implanting an epidural electrode under local anesthesia (supervised by the anesthesist) with the tip at T1, covering the painful area with paraesthesia by external stimulation (pulse width 210, rate 85 Hz), and connecting this electrode to a subcutaneously implanted pulse generator. In PVD the pain may manifest itself at rest or during walking (claudication), disabling the patient severely. Most of the patients suffer from atherosclerotic critical limb ischemia. All patients should be therapeutically refractory (medication and revascularization) to become eligible for SCS. Ulcers on the extremities should be minimal. In PVD the same implantation technique is used as in IHD except that the tip of the electrode is positioned at T10-11. In PVD the majority of the patients show significant reduction in pain and more than half of the patients show improvement of circulatory indices, as shown by Doppler, thermography, and oximetry studies. Limb salvage studies show variable results depending on the stage of the trophic changes. The underlying mechanisms of action of SCS in PVD require further elucidation.

Discriminative microcirculatory screening of patients with refractory limb ischaemia for dorsal column stimulation

OBJECTIVES

(1) To determine the proportion of patients with critical limb ischaemia refractory to invasive treatment that can be successfully treated by dorsal column stimulation (DCS), and (2) to identify potential responders to DCS by a simple test that is sufficiently predictive to limit the need for a prolonged trial stimulation period.

PATIENTS AND METHODS

Twenty patients with chronic limb-threatening ischaemia were assessed by a battery of macro- and microcirculatory tests and a DCS trial of 1 week. Favourable response during the trial determined selection for long-term stimulation.

RESULTS

During a mean observation period of 14 months, limb salvage rate (LSR) was 63% overall and 83% among patients selected after a favourable trial. Of the tests performed preoperatively, digital subtraction angiography, Doppler assessment, oscillometry, capillaroscopy, foot temperature, and transcutaneous partial pressure of oxygen (tcpO2) in the supine or sitting position did not adequately predict DCS response. The supine-sitting tcpO2 gradient (delta tcpO2) was a good predictor of DCS outcome, with an 88% LSR when delta tcpO2 > 15 Torr, dropping to 12% when delta tcpO2 < or = 15 Torr.

CONCLUSIONS

DCS is a rewarding therapeutic option in selected patients with critical limb ischaemia. delta tcpO2 appears to reliably predict response to DCS and may obviate trial stimulation in most cases.

Spinal cord stimulation for unreconstructible chronic limb ischaemia

There is still a lack of prospective randomised studies; at the present we know of only one by Jivegard et al. on a relatively small number of 51 patients. Their results are encouraging, tissue loss being reduced significantly and a trend towards increased limb salvage. The results of ongoing Dutch and American studies are awaited. It has however been shown in convincing microcirculatory studies by Jacobs et al. and others that SCS has a positive effect. Wide clinical experience has also substantiated this; were this not the case it would be hard to understand why elaborate studies by Augustinsson, Meyerson and the prolific work of Linderoth should ever have been designed. Recent communications by Lo Gerfo and others have shown that it is important to visualise the arterial tree all the way down to the foot by selective angiography before pronouncing a leg as non-reconstructible. The 3- and 5-year patency results of femoro- and popliteo-pedal bypass surgery presented by Lo Gerfo are so extraordinary--albeit probably unreproducible by all vascular surgeons--that SCS must be restricted to the truly unoperable or unreconstructable cases of CLI. SCS therefore is definitely not meant to be an alternative to reconstructive techniques!(ABSTRACT TRUNCATED AT 250 WORDS)