Improvement of sleep and pain with lemborexant administration in patients with chronic pain: a retrospective observational study.

OBJECTIVE: Patients with chronic pain often have sleep disturbances, and many patients receive sleep medications in addition to analgesics. Although there have been scattered reports of negative pain-sleep interactions, only a few reports have investigated the efficacy of sleep medication interventions in patients with chronic pain for improving sleep disturbances and reducing pain. We retrospectively examined whether lemborexant, an orexin receptor antagonist, is effective in improving sleep disturbances and reducing pain in patients with chronic pain. This study was approved by the Ethics Committee of our hospital. METHODS: The subjects were 26 patients with chronic pain undergoing treatment at our pain clinic between July 2021 and March 2022, who had been diagnosed with insomnia, with an Athens Insomnia Scale (AIS) score of ≥6 and had been started on lemborexant. The AIS score and pain score (Numeric Rating Scale [NRS]) before and after 2 and 4 weeks of starting lemborexant were investigated. RESULTS: Patients who were already taking other sleep medications, such as benzodiazepines were switched to 5 mg of lemborexant after all the other sleep medications were discontinued. Those who had not yet used sleeping pills were started on 5 mg of lemborexant. During the study course, the dose of lemborexant was adjusted at the discretion of the attending physician, based on improvement of insomnia symptoms and secondary symptoms, such as daytime sleepiness and lightheadedness. The study finally included 21 patients, excluding 5 who could not continue taking lemborexant due to side effects, such as lightheadedness. The AIS scores significantly improved, decreasing from baseline (mean ± standard deviation: 12.5 ± 4.9) to 2 weeks (7.8 ± 3.1) and 4 weeks (5.3 ± 2.9) after the start of lemborexant. No significant difference was observed in the degree of improvement in sleep disturbance between patients with or without previous sleep medications, and there was also no statistically significant improvement in the NRS score before (6.1 ± 2.7) and after 2 weeks (5.5 ± 2.3) and 4 weeks (5.9 ± 2.2) from treatment initiation.

Perioperative serum syndecan-1 concentrations in patients who underwent cardiovascular surgery with cardiopulmonary bypass and its association with the occurrence of postoperative acute kidney injury: a retrospective observational study.

BACKGROUND: Various factors can cause vascular endothelial damage during cardiovascular surgery (CVS) with cardiopulmonary bypass (CPB), which has been suggested to be associated with postoperative complications. However, few studies have specifically investigated the relationship between the degree of vascular endothelial damage and postoperative acute kidney injury (pAKI). The objectives of this study were to measure perioperative serum syndecan-1 concentrations in patients who underwent CVS with CPB, evaluate their trends, and determine their association with pAKI. METHODS: This was a descriptive and case‒control study conducted at the National University Hospital. Adult patients who underwent CVS with CPB at a national university hospital between March 15, 2016, and August 31, 2020, were included. Patients who were undergoing preoperative dialysis, had preoperative serum creatinine concentrations greater than 2.0 mg dl-1, who were undergoing surgery involving the descending aorta were excluded. The perioperative serum syndecan-1 concentration was measured, and its association with pAKI was investigated. RESULTS: Fifty-two patients were included. pAKI occurred in 18 (34.6%) of those patients. The serum syndecan-1 concentration increased after CPB initiation and exhibited bimodal peak values. The serum syndecan-1 concentration at all time points was significantly elevated compared to that after the induction of anesthesia. The serum syndecan-1 concentration at 30 min after weaning from CPB and on postoperative day 1 was associated with the occurrence of pAKI (OR = 1.10 [1.01 to 1.21], P = 0.03]; OR = 1.16 [1.01 to 1.34], P = 0.04]; and the cutoff values of the serum syndecan-1 concentration that resulted in pAKI were 101.0 ng ml-1 (sensitivity = 0.71, specificity = 0.62, area under the curve (AUC) = 0.67 (0.51 to 0.83)) and 57.1 ng ml-1 (sensitivity = 0.82, specificity = 0.56, AUC = 0.71 (0.57 to 0.86)). Multivariate logistic regression analysis revealed that the serum syndecan-1 concentration on postoperative day 1 was associated with the occurrence of pAKI (OR = 1.02 [1.00 to 1.03]; P = 0.03). CONCLUSION: The serum syndecan-1 concentration at all time points was significantly greater than that after the induction of anesthesia. The serum syndecan-1 concentration on postoperative day 1 was significantly associated with the occurrence of pAKI. TRIAL REGISTRATION: This study is not a clinical trial and is not registered with the registry.

Effectiveness of remimazolam in preventing postoperative delirium in elderly patients with proximal femoral fractures.

PURPOSE: Elderly patients with proximal femoral fractures are known to be a high-risk group for postoperative delirium (POD). The aim of this study was to determine the association of the benzodiazepine drug remimazolam with POD in elderly patients with proximal femoral fractures. METHODS: In this single-center retrospective observational study, we included patients aged 65 years or older who underwent general anesthesia for proximal femoral fractures. We collected data for the incidence of POD within 3 days after surgery. We also obtained data for complications, preoperative blood examinations, maintenance anesthetic and intraoperative vital data. The occurrence of POD in patients who received remimazolam for general anesthesia (remimazolam group) was compared to that in patients who received general anesthesia with other anesthetic agents (other group). We finally conducted a multivariate analysis to assess the independent association of remimazolam with the risk of POD. RESULTS: A total of 230 patients, including 54 patients who received remimazolam for maintenance anesthesia, were included in this study. The incidence of POD in the patients was 26.1%. The incidence of delirium within 3 days after surgery was significantly lower in the remimazolam group than in the other group (14.8% vs. 29.5%, p = 0.03). The multivariate analysis showed that the use of remimazolam independently reduced the occurrence of POD (adjusted odds ratio = 0.42, p = 0.04). CONCLUSION: This retrospective observational study showed that the use of remimazolam is independently associated with a reduced incidence of POD. Remimazolam may be considered as an option to reduce POD in elderly patients with proximal femoral fractures.

Rocuronium action can be affected by hyperventilation: a case report and computational simulation.

The neuromuscular blocking potency of rocuronium varies with respiratory pH changes, increasing at lower pH and decreasing at higher pH; thus, hyperventilation-induced respiratory alkalosis is expected to decrease the potency of rocuronium. We report a case of anesthetic management of modified electroconvulsive therapy (m-ECT) for a patient monitored with electromyography-based neuromuscular monitoring during two patterns of ventilation to elucidate their relationship and propose the possible mechanisms underlying the effects by computational simulations. Case presentation: The patient was a 25-year-old man with schizophrenia. In m-ECT, hyperventilation may be used to produce longer seizures. We compared the neuromuscular monitoring data recorded during hyperventilation and during normal ventilation while receiving the same dose of rocuronium. Despite receiving the same dose of rocuronium, the time required for the first twitch to decrease to 80% of the control value was delayed in hyperventilation compared to normal ventilation. Conclusions: This case report and computational simulation suggest that respiratory alkalosis might delay the action of rocuronium. It is necessary to consider the delayed action of rocuronium when hyperventilation is performed.

Effect of cerebrospinal fluid drainage pressure in descending and thoracoabdominal aortic repair: a prospective multicenter observational study.

PURPOSE: Cerebrospinal fluid drainage (CSFD) is recommended during open or endovascular thoracic aortic repair. However, the incidence of CSFD complications is still high. Recently, CSF pressure has been kept high to avoid complications, but the efficacy of CSFD at higher pressures has not been confirmed. We hypothesize that CSFD at higher pressures is effective for preventing motor deficits. METHODS: This prospective observational study included 14 hospitals that are members of the Japanese Society of Cardiovascular Anesthesiologists. Patients who underwent thoracic and thoracoabdominal aortic repair were divided into four groups: Group 1, CSF pressure around 10 mmHg; Group 2, CSF pressure around 15 mmHg; Group 3, CSFD initiated when motor evoked potential amplitudes decreased; and Group 4, no CSFD. We assessed the association between the CSFD group and motor deficits using mixed-effects logistic regression with a random intercept for the institution. RESULTS: Of 1072 patients in the study, 84 patients (open surgery, 51; thoracic endovascular aortic repair, 33) had motor deficits at discharge. Groups 1 and 2 were not associated with motor deficits (Group 1, odds ratio (OR): 1.53, 95% confidence interval (95% CI): 0.71-3.29, p = 0.276; Group 2, OR: 1.73, 95% CI: 0.62-4.82) when compared with Group 4. Group 3 was significantly more prone to motor deficits than Group 4 (OR: 2.56, 95% CI: 1.27-5.17, p = 0.009). CONCLUSION: CSFD is not associated with motor deficits in thoracic and thoracoabdominal aortic repair with CSF pressure around 10 or 15 mmHg.

Timing, Threshold, and Duration of Intraoperative Hypotension in Cardiac Surgery: Their Associations With Postoperative Delirium.

OBJECTIVES: To study the timing, threshold, and duration of intraoperative hypotension (IOH) associated with the risk of postoperative delirium (POD). DESIGN: A single-center retrospective observational study. SETTING: University teaching hospital. PARTICIPANTS: A total of 503 adult patients who underwent cardiac valvular surgery that required cardiopulmonary bypass (CPB). MEASUREMENTS AND MAIN RESULTS: The authors predefined the following 4 periods: (1) during surgery, (2) pre-CPB, (3) during CPB, and (4) post-CPB, and 8 thresholds of mean arterial pressure for IOH according to every 5 mmHg between 50 mmHg and 85 mmHg. The authors calculated the cumulative duration below the 8 thresholds in each period. The primary outcome was delirium defined as a score of ≥4 for at least one Intensive Care Delirium Screening Checklist assessment during 48 h after the surgery. Among 503 patients, POD occurred in 95 patients (18.9%). There was no significant association of POD with all of the thresholds of IOH in the periods of pre-CPB, during CPB, and during surgery. However, in the post-CPB period, the patients with POD had a significantly longer cumulative duration of IOH according to all of the thresholds of mean arterial pressure. In multivariate analyses, 4 IOH thresholds in the post-CPB period were associated independently with POD: <60 mmHg (odds ratio [OR] =1.84 [95% CI 1.10-3.10]), <65 mmHg (OR = 1.72 [1.01-2.92]), <70 mmHg (OR = 1.83 [1.03-3.26]), and <75 mmHg (OR = 1.94 [1.02-3.69]). CONCLUSIONS: A longer cumulative duration of IOH with the threshold between <60 and <75 mmHg that occurred after CPB was independently associated with the risk of POD.

Suppression of behavioral activity and hippocampal noradrenaline caused by surgical stress in type 2 diabetes model mice.

BACKGROUND: There has been much discussion recently about the occurrence of neuropsychological complications during the perioperative period. Diabetes is known to be one of the metabolic risk factors. Although the number of patients with diabetes mellitus (DM) has been increasing, the pathophysiology of postoperative neuropsychological dysfunction in DM patients is still unclear. Recently, a deficiency of neurotransmitters, such as monoamines, was reported to be associated with mental disorders. Therefore, we investigated the effects of surgical stress on behavioral activity and hippocampal noradrenaline (NA) level in type 2 diabetes mellitus model (T2DM) mice. METHODS: Eighty-four 6-week-old male C57BL/6J mice were divided into four groups (non-diabetes, non-diabetes with surgery, T2DM, and T2DM with surgery groups). T2DM mice were established by feeding a high-fat diet (HFD) for 8 weeks. At 14 weeks of age, fifteen mice in each group underwent a series of behavioral tests including an open field (OF) test, a novel object recognition (NOR) test and a light-dark (LD) test. In the surgery groups, open abdominal surgery with manipulation of the intestine was performed 24 h before the behavioral tests as a surgical stress. Hippocampal noradrenaline (NA) concentration was examined in six mice in each group by high-performance liquid chromatography. The data were analyzed by the Mann-Whitney U test, and p values less than 0.05 were considered significant. RESULTS: The T2DM group showed significantly increased explorative activity in the NOR test (P = 0.0016) and significantly increased frequency of transition in the LD test (P = 0.043) compared with those in the non-diabetic group before surgery. In T2DM mice, surgical stress resulted in decreased total distance in the OF test, decreased explorative activity in the NOR test, and decreased frequency of transition in the LD test (OF: P = 0.015, NOR: P = 0.009, LD: P = 0.007) and decreased hippocampal NA (P = 0.015), but such differences were not observed in the non-diabetic mice. CONCLUSIONS: Mice with T2DM induced by feeding an HFD showed increased behavioral activities, and surgical stress in T2DM mice caused postoperative hypoactivity and reduction of the hippocampal NA level.

Long-term preoperative glycemic control restored the perioperative neutrophilic phagocytosis activity in diabetic mice.

BACKGROUND: The risk of surgical site infection has been reported to be higher in patients with poorly controlled diabetes. Since chronic hyperglycemia impairs neutrophil functions, preoperative glycemic control may restore neutrophil function. However, long-term insulin therapy may lead to a delay in surgery, which may be a problem, especially in cancer surgery. It is therefore unfortunate that there have been few studies in which the optimal duration of perioperative glycemic control for diabetes with chronic hyperglycemia was investigated. Therefore, we investigated the effects of preoperative long-term insulin therapy and short-term insulin therapy on perioperative neutrophil functions in diabetic mice with chronic hyperglycemia. METHODS: Five-week-old male C57BL/6 J mice were divided into four groups (No insulin (Diabetes Mellitus: DM), Short-term insulin (DM), Long-term insulin (DM), and Non-diabetic groups). Diabetes was established by administrating repeated low-dose streptozotocin. The Short-term insulin (DM) group received insulin therapy for 6 h before the operation and the Long-term insulin (DM) group received insulin therapy for 5 days before the operation. The No insulin (DM) group and the Non-diabetic group did not receive insulin therapy. At 14 weeks of age, abdominal surgery with intestinal manipulation was performed in all four groups. We carried out a phagocytosis assay with fluorescent microspheres and a reactive oxygen species (ROS) production assay with DCFH-DA (2',7'-dichlorodihydrofluorescein diacetate) before and 24 h after the operation using FACSVerse™ with BD FACSuite™ software. RESULTS: Blood glucose was lowered by insulin therapy in the Short-term insulin (DM) and Long-term insulin (DM) groups before the operation. Neutrophilic phagocytosis activities before and after the operation were significantly restored in the Long-term insulin (DM) group compared with those in the No insulin (DM) group (before: p = 0.0008, after: p = 0.0005). However, they were not significantly restored in the Short-term insulin (DM) group. Neutrophilic ROS production activities before and after the operation were not restored in either the Short-term insulin (DM) group or Long-term insulin (DM) group. CONCLUSIONS: Preoperative and postoperative phagocytosis activities are restored by insulin therapy for 5 days before the operation but not by insulin therapy for 6 h before the operation.

Impact of Milrinone Administration in Adult Cardiac Surgery Patients: Updated Meta-Analysis.

OBJECTIVE: To determine the effects of milrinone on short-term mortality in cardiac surgery patients with focus on the presence or absence of heterogeneity of the effect. DESIGN: A systematic review and meta-analysis. SETTING AND PARTICIPANTS: Five hundred thirty-seven adult cardiac surgery patients from 12 RCTs. INTERVENTIONS: Milrinone administration. MEASUREMENTS AND MAIN RESULTS: The authors conducted a systematic Medline and Pubmed search to assess the effect of milrinone on short-term mortality in adult cardiac surgery patients. Subanalysis was performed according to the timing for commencement of milrinone administration and the type of comparators. The primary outcome was any short-term mortality. Overall analysis showed no difference in mortality rates in patients who received milrinone and patients who received comparators (odds ratio = 1.25, 95% CI 0.45-3.51, p = 0.67). In subanalysis for the timing to commence milrinone administration and the type of comparators, odds ratio for mortality varied from 0.19 (placebo as control drug, start of administration after cardiopulmonary bypass) to 2.58 (levosimendan as control drug, start of administration after cardiopulmonary bypass). CONCLUSIONS: Among RCTs to assess the effect of milrinone administration in adult cardiac surgery patients, there are wide variations of the odds ratios of administration of milrinone for short-term mortality according to the comparators and the timing of administration. This fact may suggest that a simple pooling meta-analysis is not applicable for assessing the risk and benefit of milrinone administration in an adult cardiac surgery cohort.

[Vital Sign Changes and the Requirement of Analgesics after Discontinuation of Dexmedetomidine in Patients after Esophageal Cancer Surgery.]

BACKGROUND: There is few study to examine the vital sign changes and the requirement of analgesics after discontinuation of dexmedetomidine in postopera- tive patients. METHODS: This is a retrospective observational study conducted in 74 patients after esophageal cancer sur- gery. We recorded vital signs including blood pressure, heart rate and respiratory rate one hour before discon- tinuation of dexmedetomidine, and at 1, 2, 4, 6 hours after its discontinuation. We also recorded the use of opioid and analgesic within 6 hours after discontinua- tion. RESULTS: Mean blood pressure, pulse rate, and respi- ratory rate significantly increased after DEX discon- tinuation. Compared with the data before discontinua- tion, the mean blood pressure increased by 13.3 mmHg, heart rate increased by 7.5 beats - min- and respira- tory rate increased by 3.0 times - min-' in average at 6 hours after discontinuation. There were 28 patients (38%) who required the additional analgesics within 6 hours after discontinuation. CONCLUSIONS: After discontinuation of dexmedetomi- dine, significant changes of vital signs, especially in mean blood pressure, were observed in post-esopha- gectomy patients. About 38% of them required addi- tional analgesics within 6 hours after dexmedetomidine discontinuation.

Perioperative Management of a Needle-Phobic Parturient for a Cesarean Section: A Case Report.

We describe the perioperative management of a pregnant woman with severe needle phobia who underwent a cesarean section. General anesthesia with slow induction using an inhalant anesthetic for cesarean section is a rare and unique situation. Furthermore, the management of this case was more complicated because the patient not only refused the puncture procedure but also refused the presence of an indwelling object when she woke up from the anesthesia. After the operation, the patient was admitted to the intensive care unit (ICU) and received mechanical ventilation under deep sedation. The patient was managed under sedation until the day after surgery, and both mother and child progressed without perioperative complications.

Severe hypotension and postoperative cardiac arrest caused by 5-aminolevulinic acid: a case report.

BACKGROUND: Although 5-aminolevulinic acid is useful for the photodynamic diagnosis of bladder tumors, it often causes severe intraoperative hypotension. We report a case of postoperative cardiac arrest in addition to severe intraoperative hypotension, probably owing to the use of 5-aminolevulinic acid. CASE PRESENTATION: An 81-year-old Japanese man was scheduled to undergo transurethral resection of bladder tumor. The patient took 5-aminolevulinic acid orally 2 hours before entering the operating room. After the induction of anesthesia, his blood pressure decreased to 47/33 mmHg. The patient's hypotension did not improve even after noradrenaline was administered. After awakening from anesthesia, the patient's systolic blood pressure increased to approximately 100 mmHg, but approximately 5 hours after returning to the ward, cardiac arrest occurred for approximately 12 seconds. CONCLUSION: We experienced a case of postoperative cardiac arrest in a patient, probably owing to the use of 5-aminolevulinic acid. Although the cause of cardiac arrest is unknown, perioperative hemodynamic management must be carefully performed in patients taking 5-aminolevulinic acid.

Percutaneous retrocrural versus ultrasound-guided coeliac plexus neurolysis for refractory pancreatic cancer pain.

We report a successful case of fluoroscopic percutaneous retrocrural coeliac plexus neurolysis (PRCPN) for pancreatic cancer pain refractory to endoscopic ultrasound-guided coeliac plexus neurolysis (EUS-CPN). A 55-year-old man with upper abdominal pain due to end-stage pancreatic cancer underwent EUS-CPN. Although CT revealed distribution of the contrast medium with neurolytic agent around the left and cephalic sides of the coeliac artery, the pain did not improve and became even more severe. PRCPN was performed, resulting in the drastic improvement of pain immediately. PRCPN should be considered when EUS-CPN is not effective.

A Case of a Highly Obese Covid-19 Patient with Severe Hypoxemia and Subcutaneous Mediastinal Emphysema Who Was Rescued by Early Introduction of ECMO.

We conducted the treatment of a highly obese patient with severe Covid-19 pneumonia who had a history of asthma. When she arrived at the hospital, she was already intubated and had mediastinal emphysema and severe hypoxemia. Because the patient's condition did not improve with mechanical ventilation, we introduced extracorporeal membrane oxygenation (ECMO) immediately after admission. The patient improved with early induction of ECMO and prone positioning. In the management of patients with severe Covid-19 pneumonia, early introduction of ECMO should be considered if oxygenation does not improve with mechanical ventilation, and prone positioning can also be effective.

Anesthetic management of Stanford type B acute aortic dissection that occurred during transcatheter aortic valve implantation under monitored anesthesia care: A case report.

We report a case involving anesthetic management of Stanford type B acute aortic dissection occurred during transcatheter aortic valve implantation (TAVI) under monitored anesthesia care (MAC) in a patient with aortic stenosis (AS). An 87-year-old woman was undergoing TAVI under MAC for severe AS. During the surgery, the patient suddenly moved possibly because of pain. This was followed by hemodynamic collapse. She was then transitioned to general anesthesia, and extracorporeal membrane oxygenation (ECMO) was initiated. Transesophageal echocardiography revealed a Stanford type B acute aortic dissection, which was safely managed perioperatively with appropriate interventions.

Antinociceptive effects of intrathecal landiolol injection in a rat formalin pain model.

Perioperative beta-blocker administration has recently been recommended for patients undergoing cardiac or other surgery due to the beneficial cardiovascular effects of these agents. In addition, some studies have reported that perioperatively administered beta-blockers also have analgesic effects. In this study, to investigate the antinociceptive effects and the analgesic profile of landiolol, we examined the effects of intrathecal landiolol administration on nociceptive pain behavior and c-fos mRNA expression (a neural marker of pain) in the spinal cord using a rat formalin model. We found that pain-related behavior was inhibited by intrathecal landiolol administration. Moreover, the increase in c-fos mRNA expression on the formalin-injected side was less pronounced in rats administered landiolol than in saline administered controls. Thus, intrathecal administration of landiolol exhibited antinociceptive effects. Further investigation of the antinociceptive mechanism of landiolol is required.

Decoy strategy targeting the brain-derived neurotrophic factor exon I to attenuate tactile allodynia in the neuropathic pain model of rats.

The mechanism underlying neuropathic pain is still largely unclear. Recently, much attention has been focused on the role of brain-derived neurotrophic factor (BDNF) as a neuromodulator in the spinal cord. We previously reported that the expression of Bdnf exon I mRNA was remarkably up-regulated in the dorsal root ganglion (DRG) neurons with the rat L5 spinal nerve ligation (SNL) model. In the present study, we investigated whether neuropathic pain response would be reduced by the inhibition of the Bdnf exon I in the rat SNL model. We identified the promoter region of exon I and synthesized the decoy ODNs targeting the region. Reverse transcription-polymerase chain reaction analysis confirmed that the decoy ODN treatment reduced SNL-induced Bdnf exon I mRNA up-regulation in ipsilateral L4 and L5 DRGs. Furthermore, post-treatment with the decoy ODNs significantly attenuated SNL-induced tactile allodynia. This study suggested that decoy ODNs targeting the Bdnf exon I might provide a novel analgesic strategy for the treatment of neuropathic pain.

Mean amplitude of glycemic excursions in septic patients and its association with outcomes: A prospective observational study using continuous glucose monitoring.

PURPOSE: To apply continuous glucose monitoring (CGM) and determine the mean amplitude of glycemic excursions (MAGE) in septic patients and to assess the associations of MAGE with outcomes and oxidative stress. MATERIALS AND METHODS: This study was conducted in adult septic patients expected to require intensive care for >48 h. We continuously measured blood glucose level for the first 48 h in the ICU using FreeStyle Libre®. MAGE was calculated using glycemic information obtained by CGM during the study period of 48 h. The primary outcome was 90-day all-cause mortality. The secondary outcomes were 90-day ICU-free days and the concentration of urinary 8-isoprostaglandinF2α measured 48 h after commencement of the study as a surrogate of oxidative stress. RESULTS: Forty patients were included in this study. Median of MAGE was higher in non-survivors than in survivors: 68.8 (IQR;39.7-97.2) vs. 39.3 (IQR;19.9-53.3), p = 0.02. In multivariate analysis, MAGE was independently associated with 90-day all-cause mortality rate (p = 0.02), urinary 8-isoprostaglandinF2α level (p = 0.03) and 90-day ICU-free survival days (p = 0.03). CONCLUSIONS: In the current study, MAGE for the first 48 h of treatment that was obtained by using CGM was associated with 90-day all-cause mortality, 90-day ICU-free days and urinary 8-isoprostaglandinF2α level in septic patients.

Pain induces stable, active microcircuits in the somatosensory cortex that provide a therapeutic target.

Sustained neuropathic pain from injury or inflammation remains a major burden for society. Rodent pain models have informed some cellular mechanisms increasing neuronal excitability within the spinal cord and primary somatosensory cortex (S1), but how activity patterns within these circuits change during pain remains unclear. We have applied multiphoton in vivo imaging and holographic stimulation to examine single S1 neuron activity patterns and connectivity during sustained pain. Following pain induction, there is an increase in synchronized neuronal activity and connectivity within S1, indicating the formation of pain circuits. Artificially increasing neuronal activity and synchrony using DREADDs reduced pain thresholds. The expression of N-type voltage-dependent Ca2+ channel subunits in S1 was increased after pain induction, and locally blocking these channels reduced both the synchrony and allodynia associated with inflammatory pain. Targeting these S1 pain circuits, via inhibiting N-type Ca2+ channels or other approaches, may provide ways to reduce inflammatory pain.

Continuous Mandibular Nerve Block for Intractable Mandibular Pain Due to Antiresorptive Agent-Related Osteonecrosis of the Jaw: A Case Report.

Antiresorptive agent-related osteonecrosis of the jaw (ARONJ) causes severe pain that cannot be controlled well by common analgesic drugs. This is a first case report of intractable mandibular pain due to ARONJ that was eliminated by a continuous mandibular nerve block. A 72-year-old woman with osteoporosis had been administered bisphosphonate. One year after extraction of her tooth, she was diagnosed as having ARONJ. Jaw pain was so severe that she was unable to open her mouth and eat. We performed a continuous mandibular nerve block through an indwelling catheter with levobupivacaine for pain management. After the procedure, her rest pain was markedly improved, and the pain induced by opening her mouth disappeared. We conclude that a continuous mandibular nerve block may be helpful in the management of ARONJ.