High-frequency (10 kHz) spinal cord stimulation for the treatment of focal, chronic postsurgical neuropathic pain: results from a prospective study in Belgium

Aim: Chronic postsurgical pain (CPSP) is a common complication of surgery. This study was conducted to evaluate the efficacy and safety of paresthesia-free, 10-kHz spinal cord stimulation (SCS) as a treatment for CPSP. Patients & methods: Subjects in this prospective, single-arm study had an average pain intensity of ≥5 cm on a 10-cm visual analog scale. The subjects who had pain relief of ≥50% (response) with temporary trial stimulation were permanently implanted with 10-kHz SCS and assessed for 1 year. Results: At 12 months, 94% of subjects were responders to 10-kHz SCS, and 88% had pain remission (visual analog scale ≤2.5 cm). Conclusion: The pain relief was durable in CPSP subjects and the safety profile of 10-kHz SCS was as expected. Clinical trial registration: VT005076953 (Privacy Commission of Belgium).

10 kHz Spinal Cord Stimulation for the Treatment of Failed Back Surgery Syndrome with Predominant Leg Pain: Results from a Prospective Study in Patients from the Dutch Healthcare System

INTRODUCTION

Persistent back/and or leg pain is a common outcome after spinal surgery (otherwise known as failed back surgery syndrome [FBSS]). Studies have shown that spinal cord stimulation (SCS) at 10 kHz provides effective analgesia in FBSS patients with both back and leg pain symptoms and in those with predominant back pain. This study is the first to evaluate the therapy in FBSS patients with predominant leg pain.

METHODS

The safety and efficacy of 10 kHz SCS was evaluated in an uncontrolled, open-label, prospective study of FBSS patients with predominant leg pain in the Netherlands. Follow-ups were performed at 1, 3, 6, and 12 months post implantation.

RESULTS

Sixty out of 68 patients (88%) experienced sufficient pain relief during a stimulation trial. Of these, 58 proceeded to permanent implantation of a 10 kHz SCS system. After 12 months of treatment, 80% of patients experienced ≥ 50% reduction in baseline leg pain, and a similar proportion (76%) experienced ≥ 50% reduction in baseline back pain. At least two-thirds of patients were also leg pain and back pain remitters (visual analog scale [VAS] ≤ 2.5 cm). The therapy was also associated with a general improvement in patients' quality of life, as measured by secondary outcomes including disability, perception of health improvement, mental well-being, and satisfaction. A positive impact on opioid consumption was also observed.

CONCLUSIONS

Consistent with previous findings, 10 kHz SCS for the treatment of FBSS patients with predominant radicular symptoms is safe and effective and is associated with improved quality of life.

A chlorophyll a fluorescence-based Lemna minor bioassay to monitor microbial degradation of nanomolar to micromolar concentrations of linuron

A plant-microbial bioassay, based on the aquatic macrophyte Lemna minor L. (duckweed), was used to monitor biodegradation of nano- and micromolar concentrations of the phenylurea herbicide linuron. After 7 days of exposure to linuron, log-logistic-based dose-response analysis revealed significant growth inhibition on the total frond area of L. minor when linuron concentrations > or = 80 nM were added to the bioassay. A plant-protective effect was obtained for all concentrations > 80 nM by inoculation with either a bacterial consortium or Variovorax paradoxus WDL1, which is probably the main actor in this consortium. The outcome of the plant-microbe-toxicant interaction was also assessed using pulse amplitude-modulated chlorophyll a fluorescence and chlorophyll a fluorescence imaging. Linuron toxicity to L. minor became apparent as a significant decrease in the effective quantum yield (Delta F/Fm') within 90 min after exposure of the plants to linuron concentrations > or = 160 nM. Inoculation of the bioassay with the linuron-degrading bacteria neutralized the effect on the effective quantum yield at concentrations > or = 160 nM, indicating microbial degradation of these concentrations. The chlorophyll a fluorescence-based Lemna bioassay described here offers a sensitive, fast and cost-effective approach to study the potential of biodegrading microorganisms to break down minute concentrations of photosynthesis-inhibiting xenobiotics.