Long-Term Analgesic Efficacy of Neurolytic Splanchnic Nerve Block via the Transintervertebral Disc Approach to Retrocrural Space: A Multicenter Retrospective Study.

INTRODUCTION: The celiac plexus block is effective for treating intractable cancer pain and has been the focus of many studies. At our affiliated institution, fluoroscopy-guided splanchnic nerve block with a single needle via the transintervertebral disc approach was the first choice of treatment. The short-term efficacy of this technique has been reported, but the long-term efficacy is not clear. In the present study, we investigated the long-term analgesic efficacy of this technique. METHODS: This multicenter, retrospective, observational study reviewed the medical records of patients who underwent neurolytic splanchnic nerve block (NSNB) via the transintervertebral disc approach for intractable cancer pain at five tertiary hospitals in Japan from April 2005 to October 2020. The primary outcome was the long-term analgesic efficacy of a one-time NSNB via the transintervertebral disc approach. RESULTS: In total, 76 patients were included in the analysis. The median lowest numerical rating scale (NRS) score was 1 within 14 days. At 1, 2, 3, and 6 months after the nerve block, the median NRS score was also ≤ 2, while the median equivalent oral morphine dose did not show any clinically noticeable increase at those times. CONCLUSION: The long-term analgesic efficacy of NSNB via the transintervertebral disc approach in patients with intractable cancer pain has been demonstrated.

The celiac plexus block is effective for treating intractable cancer pain and has been the focus of many studies. The celiac plexus nerve block relieves intractable cancer pain arising from the pancreas or other organs in close proximity, and the splanchnic nerve block is considered clinically equivalent to the celiac plexus block for analgesia. At our affiliated institution, fluoroscopy-guided neurolytic splanchnic nerve block with a single needle via the transintervertebral disc approach is the first choice of treatment because it is technically simpler and less invasive than other approaches. While the short-term efficacy of this technique is known, its long-term efficacy remains unclear. Thus, this multicenter, retrospective, observational study aimed to investigate the long-term analgesic efficacy of a neurolytic splanchnic nerve block via the transintervertebral disc approach. The medical records of patients in whom intractable cancer pain was managed using this technique at five tertiary hospitals in Japan were analyzed. The primary outcome was the long-term analgesic efficacy of a one-time neurolytic splanchnic nerve block via the transintervertebral disc approach. The median lowest numerical rating scale score was 1 within 14 days. At 1, 2, 3, and 6 months after the nerve block, the median numerical rating scale score was also ≤ 2, while the median equivalent oral morphine dose did not show any clinically noticeable increase at those times. This technique may reduce opioid dose and associated side effects compared with long-term conventional pharmacotherapy alone.

Efficacy and Safety of Neurolytic Splanchnic Nerve Block via Transintervertebral Disc Approach to Retrocrural Space: A Multicenter Retrospective Study.

INTRODUCTION: Celiac plexus block is effective for treating intractable cancer pain and has been the focus of many studies. Several guiding techniques such as fluoroscopy, computed tomography, and endoscopy have been devised, and the target of the block has varied in previous studies as both the celiac plexus and splanchnic nerve, which is the main origin of the celiac plexus, have been targeted. At our affiliated institution, fluoroscopy-guided splanchnic nerve block with a single needle via transintervertebral disc approach is the first choice. However, there have been few reports on the use of this technique. This study investigated the efficacy and safety of this technique. METHODS: This multicenter retrospective observational study reviewed the medical records of patients who underwent neurolytic splanchnic nerve block (NSNB) via transintervertebral disc approach for intractable cancer pain at five tertiary hospitals in Japan from April 2005 to October 2020. The primary outcome was the clinical success ratio of NSNB, and the secondary outcome was the incidence ratio of NSNB-related adverse events. RESULTS: In total, 103 patients were included in the analysis. Of these, 77 patients met the definition of clinical success, with a ratio of 74.8%. The incidence ratio of NSNB-related adverse events was 40.8% (hypotension, 21.4%; alcohol intoxication, 13.6%; diarrhea, 11.7%; and vascular puncture, 3.9%; duplicates were present). All adverse events improved with observation and symptomatic treatment only. No patient had infection or serious adverse events such as organ or nerve damage. CONCLUSIONS: The clinical success ratio of this technique was 74.8%. Although the incidence of adverse events was 40.8%, all events were mild and no serious adverse events were observed. The findings demonstrate the efficacy and safety of our NSNB in patients with intractable cancer pain.

In patients with intractable pain from abdominal cancer, fluoroscopy-guided neurolytic splanchnic nerve block via transintervertebral disc approach is an effective and safe procedure. It can be completed with a single needle puncture, and is anatomically less likely to cause organ or nerve damage compared with other approaches. The analgesia produced by this technique, along with conventional pharmacotherapy for cancer pain, may reduce opioid dose and its side effects and improve patients' quality of life.

Prevalence of neuropathic pain in terminally ill patients with cancer admitted to a general ward: a prospective observational study.

OBJECTIVES: To determine the prevalence of neuropathic pain among terminally ill patients with cancer admitted to a general ward, using the International Association for the Study of Pain algorithm. METHODS: This prospective observational study was conducted at a tertiary care center. We enrolled terminally ill patients with cancer admitted to the general ward between September 2018 and September 2019. On the day of consultation with our palliative care team, pain management clinicians examined and diagnosed neuropathic pain using the International Association for the Study of Pain diagnostic criteria. RESULTS: A total of 108 patients were enrolled during the study period. The median age was 69 years (interquartile range [IQR] 58.3-76.8 years), 72 patients (66.7%) were men, and the median survival time was 33 days (IQR 14.3-62 days). Of the 108 patients, 33 (30.6%) had neuropathic pain. Patients with neuropathic pain had more severe pain than those without neuropathic pain. CONCLUSIONS: The prevalence of neuropathic pain in terminally ill patients with cancer admitted to a Japanese general ward was 30.6%. Further studies are warranted to elucidate whether the accurate diagnosis of neuropathic pain can improve pain control and/or patient conditions.

Spinal cord stimulation modulates supraspinal centers of the descending antinociceptive system in rats with unilateral spinal nerve injury.

BACKGROUND: The descending antinociceptive system (DAS) is thought to play crucial roles in the antinociceptive effect of spinal cord stimulation (SCS), especially through its serotonergic pathway. The nucleus raphe magnus (NRM) in the rostral ventromedial medulla is a major source of serotonin [5-hydroxytryptamine (5-HT)] to the DAS, but the role of the dorsal raphe nucleus (DRN) in the ventral periaqueductal gray matter is still unclear. Moreover, the influence of the noradrenergic pathway is largely unknown. In this study, we evaluated the involvement of these serotonergic and noradrenergic pathways in SCS-induced antinociception by behavioral analysis of spinal nerve-ligated (SNL) rats. We also investigated immunohistochemical changes in the DRN and locus coeruleus (LC), regarded as the adrenergic center of the DAS, and expression changes of synthetic enzymes of 5-HT [tryptophan hydroxylase (TPH)] and norepinephrine [dopamine ß-hydroxylase (DßH)] in the spinal dorsal horn. RESULTS: Intrathecally administered methysergide, a 5-HT1- and 5-HT2-receptor antagonist, and idazoxan, an α2-adrenergic receptor antagonist, equally abolished the antinociceptive effect of SCS. The numbers of TPH-positive serotonergic and phosphorylated cyclic AMP response element binding protein (pCREB)-positive neurons and percentage of pCREB-positive serotonergic neurons in the DRN significantly increased after 3-h SCS. Further, the ipsilateral-to-contralateral immunoreactivity ratio of DßH increased in the LC of SNL rats and reached the level seen in naïve rats, even though the number of pCREB-positive neurons in the LC was unchanged by SNL and SCS. Moreover, 3-h SCS did not increase the expression levels of TPH and DßH in the spinal dorsal horn. CONCLUSIONS: The serotonergic and noradrenergic pathways of the DAS are involved in the antinociceptive effect of SCS, but activation of the DRN might primarily be responsible for this effect, and the LC may have a smaller contribution. SCS does not potentiate the synthetic enzymes of 5HT and norepinephrine in the neuropathic spinal cord.

Relationship between ventral lumbar disc protrusion and contrast medium leakage during sympathetic nerve block.

Ventral disc protrusions have been neglected because they are asymptomatic. Lumbar sympathetic nerve block (LSNB) is one of the clinical choices for refractory low back pain treatment. Leakage of the contrast medium may occur and lead to complications, especially when using a neurolytic agent. In this study, we retrospectively reviewed the magnetic resonance images (MRIs) of 52 consecutive patients with refractory low back pain due to lumbar spinal canal stenosis who underwent LSNB, and graded ventral disc protrusion at the L1/2 to L5/S1 vertebral discs on a three-point scale (grade 0 = no protrusion, grade 1 = protrusion without migration, grade 2 = protrusion with migration). We also determined if there was leakage of contrast medium in LSNB. Ventral disc protrusion was observed in all patients, and 75 % (39/52) had grade 2 protrusion in the L1/2-L3/4 vertebral discs. Moreover, the incidence of contrast medium leakage was significantly higher at the vertebrae that had grade 2 protrusion than at those with less protrusion. We revealed a higher incidence of ventral disc protrusion of the lumbar vertebrae than previously reported, and that the incidence of leakage in LSNB increased when ventral disc protrusion was present. To avoid complications, attention should be paid to ventral disc protrusions before performing LSNB.

Efficacy of a metered-dose 8% lidocaine pump spray for patients with post-herpetic neuralgia.

OBJECTIVE: Topical lidocaine patch is effective in the treatment of post-herpetic neuralgia (PHN), but not suited for paroxysmal pain because of the long latency of analgesia. Here, we examined the efficacy of 8% lidocaine pump spray (Xylocaine pump spray, XPS) for PHN. DESIGN: Twenty-four patients with PHN were recruited into a randomized, double-blind, placebo-controlled, crossover study (study 1), and 100 patients with PHN were recruited into an open-labeled study (study 2). In study 1, patients were randomized to receive either XPS or saline placebo pump spray (PPS) applied to the painful skin areas. Following a 7-day period, patients were crossed over to receive the alternative treatment. In study 2, XPS was prescribed for patients who were advised to use the spray anytime, with a 2-hour gap between applications, for 2 weeks. The pain was assessed with a visual analogue scale (VAS). Details of use were noted in the diary. RESULTS: In study 1, greater decreases in VAS of persistent pain followed application of XPS (baseline: 6.1 +/- 1.7 cm, 15-minute post-spray: 2.3 +/- 2.5 cm, mean +/- SD) than with PPS (6.1 +/- 1.7 cm, 5.7 +/- 1.6 cm, [P < 0.01]). The effect persisted for a median of 4.5 hours (range, 2 to 24 hours) after application. In study 2, 13 of 100 patients discontinued the treatment because of mild local side effects or insufficient effect. In the remaining 87 patients, XPS maintained significant pain relief relative to baseline throughout the 2-week period. Satisfaction with the therapy was reported by 79% of patients. CONCLUSIONS: In both studies, XPS provided a significant improvement in PHN due to its prompt analgesia, lack of systemic side effects, and convenience of use.

[The effects of inhaled carbon monoxide on lung injury in rats caused by lipopolysaccharide].

BACKGROUND: Carbon monoxide (CO) has long been considered a toxic substance. Recent studies have revealed that CO may play an important role in intercellular signaling. We hypothesized that CO modulates the inflammatory mechanisms. METHODS: SD rats (each study group consisting of 7 animals) inhaled 250 ppm of CO one hour prior to LPS challenges. These animals were incubated for a particular period of time (four different length of time; 1, 2, 4, and 8 hours). The control group (each study group consisting of 6 animals) had been left in the room air. Both groups were instilled with LPS (1 mg) into the lungs. At the end of each period, animals were exsanguinated, broncho-alveolar lavage (BAL) and blood sampling were performed, and a part of the small intestine was harvested. PMN numbers, protein, TNF, and IL-10 concentrations in BAL fluid were measured. Plasma TNF and IL-10 were also measured. The Wet/Dry ratio of a small intestine was calculated. RESULTS: In the CO-inhalation group, the anti-inflammatory cytokine IL-10 concentration in the BAL fluid was higher at 8 hours after LPS challenge than the counterpart of room air group (37.6 +/- 11.4 pg.ml-1 vs. 92.8 +/- 31.5 pg.ml-1, P < 0.05). W/D ratio decreased (3.29 +/- 0.2 vs. 2.94 +/- 0.06, P < 0.05). CONCLUSION: These findings indicated that CO inhalation might modulate the inflammatory response to LPS. Further study is needed to prove the therapeutic role of CO inhalation without serious adverse effects.