Management of cardiac pacemaker in a patient with spinal cord stimulator implant.

Spinal cord stimulation reduces pain of critical ischaemia in patients with severe inoperable coronary artery and peripheral vascular disease by increasing microvascular flow. Patients with cardiac pacemaker may be denied a spinal cord stimulator (SCS) implant because of the risk of compromising pacemaker function by inhibition or reversion to asynchronous noise-pacing mode. We describe the management of a patient with an SCS implant for lower limb ischaemia who required a pacemaker. We suggest that with modern pacemakers it is safe to implant a spinal cord stimulator simultaneously with a pacemaker provided adequate precautions are taken to prevent interdevice interference.

Long-term experience with implanted intrathecal drug administration systems for failed back syndrome and chronic mechanical low back pain.

BACKGROUND: Continuous intrathecal drug delivery has been shown in open studies to improve pain and quality of life in those with intractable back pain who have had spinal surgery. There is limited data on long term effects and and even less for patients with mechanical back pain without prior spinal surgery. METHODS: We have investigated spinal drug administration systems for patients with failed back syndrome and chronic mechanical low back pain by patient questionnaire study of the efficacy of this therapy and a case notes review. RESULTS: 36 patients (97% of 37 approached) completed questionnaires, 24 with failed back syndrome and 12 with chronic mechanical low back pain. Recalled pre-treatment levels with current post-treatment levels of pain and a range of quality of life measures (recorded on 11-point numerical rating scales) were compared. Pain improved significantly in both groups (Wilcoxan signed ranks test, p < 0.005). The majority of quality of life measures improved significantly in the failed back syndrome group (Wilcoxan signed ranks test, p < 0.005) although work interruption and the effect of pain on sex life did not change. There was a trend towards improvement in the majority of quality of life measures in the mechanical back pain group but this did not reach statistical significance due to the smaller numbers in this cohort (p > 0.005, Wilcoxan signed ranks test with Bonferroni correction).Diamorphine was used in all 37 patients, bupivacaine in 32, clonidine in 27 and baclofen in 3. The mean dose of diamorphine increased for the first 2 years but did not change 2-6 years post implant, averaging 4.5 mg/day. Revision surgery was required in 24% of cases, but reduced to 12% in the later years of our experience. CONCLUSIONS: We conclude that spinal drug administration systems appear to be of benefit in alleviating pain in the failed back syndrome and chronic mechanical low back pain but need to be examined prospectively.

Lysosomal enzyme release from the lungs after cardiopulmonary bypass.

The activity of some lysosomal enzymes has been investigated in venous and arterial blood collected from patients undergoing cardiopulmonary bypass. Before bypass, there is no arterio-venous difference in the activity of n-acetyl-beta glucosaminidase, beta-glucuronidase or lysozyme. After operation, the activity of n-acetyl-beta-glucosaminidase is greater in arterial than in superior caval blood within the first 24 h after bypass, and a small arterio-venous increment in the activity of beta-glucuronidase can also be detected towards the end of the first day. The site of enzyme release has not been identified with certainty but may lie within the pulmonary circulation.

Lysosomal enzyme release during cardiopulmonary bypass.

Lysosomal enzyme release occurs during cardiopulmonary bypass in man but the tissues from which these enzymes originate have not been identified. The activity of N-acetyl beta-glucosaminidase in plasma increases to a degree which is proportional to the duration of bypass and this enzyme may therefore be a better marker than beta-glucuronidase of tissue damage caused by cardiopulmonary bypass, as distinct from tissue damage solely to the operative procedure.