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Background: Dexmedetomidine is a highly selective a2 adrenergic agonist that has been shown to decrease the intensity of opioid-induced hyperalgesia (OIH). We aimed to investigate the antihyperalgesic effects of dexmedetomidine on high-dose remifentanil-induced hyperalgesia. Methods: Ninety American Society of Anesthesiologists physical status I-II patients undergoing laparoscopically assisted vaginal hysterectomy (LAVH) were randomly assigned to one of the following three groups, each of which received either dexmedetomidine (an initial dose of 1.0 µg/kg for 10 min, followed by a continuous infusion of 0.7 µg/kg/hr) or placebo saline 15 min before the induction of anesthesia and intraoperative remifentanil infusion: group C received a placebo and 0.05 µg/kg/min remifentanil; group RH received a placebo and 0.3 µg/kg/min remifentanil; and group DRH received dexmedetomidine and 0.3 µg/kg/min remifentanil. Results: The mechanical hyperalgesia threshold 24 hr after surgery was significantly lower in group RH than in the other two groups. Postoperative pain intensity using visual analog scale (VAS) and cumulative volume of a patient-controlled analgesia (PCA) containing morphine over 24 hr were significantly greater in group RH than in group DRH. The time to the first postoperative analgesic requirement was significantly shorter in group RH than in the other two groups. The desflurane requirement was significantly greater in group C than in the other groups. The frequency of hypotension and bradycardia was significantly higher, but shivering and postoperative nausea and vomiting were significantly lower in group DRH than in the other two groups. Conclusions: High-doses of remifentanil induced hyperalgesia, which presented a decreased mechanical hyperalgesia threshold, enhanced pain intensity, a shorter time to first postoperative analgesic requirement, and greater morphine consumption, but dexmedetomidine efficiently alleviated those symptoms. Dexmedetomidine may be a novel and effective treatment option for preventing or attenuating OIH. [ABSTRACT FROM AUTHOR]

Background: Dexmedetomidine is a highly selective α2 adrenergic agonist that has been shown to decrease the intensity of opioid-induced hyperalgesia (OIH). We aimed to investigate the antihyperalgesic effects of dexmedetomidine on high-dose remifentanil-induced hyperalgesia. Methods: Ninety American Society of Anesthesiologists physical status I-II patients undergoing laparoscopically assisted vaginal hysterectomy (LAVH) were randomly assigned to one of the following three groups, each of which received either dexmedetomidine (an initial dose of 1.0 μg/kg for 10 min, followed by a continuous infusion of 0.7 μg/kg/hr) or placebo saline 15 min before the induction of anesthesia and intraoperative remifentanil infusion: group C received a placebo and 0.05 μg/kg/min remifentanil; group RH received a placebo and 0.3 μg/kg/min remifentanil; and group DRH received dexmedetomidine and 0.3 μg/kg/min remifentanil. Results: The mechanical hyperalgesia threshold 24 hr after surgery was significantly lower in group RH than in the other two groups. Postoperative pain intensity using visual analog scale (VAS) and cumulative volume of a patient-controlled analgesia (PCA) containing morphine over 24 hr were significantly greater in group RH than in group DRH. The time to the first postoperative analgesic requirement was significantly shorter in group RH than in the other two groups. The desflurane requirement was significantly greater in group C than in the other groups. The frequency of hypotension and bradycardia was significantly higher, but shivering and postoperative nausea and vomiting were significantly lower in group DRH than in the other two groups. Conclusions: High-doses of remifentanil induced hyperalgesia, which presented a decreased mechanical hyperalgesia threshold, enhanced pain intensity, a shorter time to first postoperative analgesic requirement, and greater morphine consumption, but dexmedetomidine efficiently alleviated those symptoms. Dexmedetomidine may be a novel and effective treatment option for preventing or attenuating OIH. [ABSTRACT FROM AUTHOR]

Lumbar facet joints have been implicated in chronic low back pain in up to 45% of patients with low back pain (LBP). Facet joint pain diagnosis and management are always challenging for pain physicians. Facet joint pain is not diagnosed by specific demographic features, pain characteristics, or physical findings, even though electrodiagnostic studies and imaging modalities are available. Although comparative local anesthetics or placebo saline injections can be used, diagnostic blocks are the only reliable diagnostic measures according to the current literature. Treatment of chronic LBP arising due to facet joint includes intraarticular injections, medial branch blocks, and radiofrequency neurotomy. However, the evidence of their clinical efficacy is continuously under scrutiny. Pain physicians must have a detailed understanding of the spinal anatomy in order to perform safe and effective interventional procedures. This review outlines the important aspects of spinal anatomy as they relate to interventional pain management related to facet joint injections. Additionally, we provide a comprehensive review of the procedure and clinical evidence., Competing Interests: CONFLICTS OF INTEREST No potential conflict of interest relevant to this article was reported., (Copyright © the Korean Society of Anesthesiologists, 2019.)

Background: Various developments in imaging techniques, interventional procedures, and medications for pain management have beneficial consequences. However, the nature of pain management often results in physicians becoming involved in medico-legal disputes with patients who purposely or accidentally bring litigation., Methods: Data on medical disputes cases related to pain management were collected and analyzed through the Korea Medical Dispute Mediation and Arbitration Agency from 2012 to 2016., Results: In total, we identified 210 public-disclosed cases; of these, we identified 36 cases related to pain management. The department of orthopedics (n = 9, 25%) was the most related to these pain management cases. Pain management was most commonly offered for pain in the lumbar region (n = 13, 37%), lower extremities (n = 12, 34%), and for infection (n = 7, 19%). The time spent resolving disputes ranged from 8.0 to 17.5 months and the final settlement amount ranged from 1,800,000 to 15,000,000 Korean won. Causal relationships and medical malpractice were the most common controversial subjects of legal debate., Conclusions: Various characteristics of medical disputes related to pain management in Korea were identified. Information regarding medical disputes in pain management should be available to help prevent further disputes and litigation, which is also useful to both patients and pain physicians. Guidelines and recommendations for pain management are needed, especially those focused on medico-legal cases., Competing Interests: CONFLICTS OF INTEREST No potential conflict of interest relevant to this article was reported., (Copyright © the Korean Society of Anesthesiologists, 2020.)

Background: Although one lung ventilation (OLV) is frequently used for facilitating thoracic surgical procedures, arterial hypoxemia can occur while using one lung anesthesia. Continuous positive airway pressure (CPAP) in 5 or 10 cmH(2)O to the non-ventilating lung is commonly recommended to prevent hypoxemia. We evaluated the effects of incremental CPAP to the non-ventilating lung on arterial oxygenation and pulmonary shunt without obstruction of the surgical field during OLV., Methods: Twenty patients that were scheduled for one lung anesthesia were included in this study. Systemic and pulmonary hemodynamic data and blood gas analysis was recorded every fifteen minutes according to the patient's positions and CPAP levels. CPAP was applied from 0 cmH(2)O by 3 cmH(2)O increments until a surgeon notifies that the surgical field was obstructed by the expanded lung. Following that, pulmonary shunt fraction (Q(S)/Q(T)) was calculated., Results: There were no significant differences of Q(S)/Q(T) between supine and lateral positions with two lung ventilation (TLV). OLV significantly decreased arterial oxygen partial pressure (PaO(2)) and increased Q(S)/Q(T) compared to TLV. PaO(2) and Q(S)/Q(T) significantly improved at 6 and 9 cmH(2)O of CPAP compared to 0 cmH(2)O. However, there were no significant differences of PaO(2) and Q(S)/Q(T) between 6 and 9 cmH(2)O CPAP. In 18 patients (90%), surgical fields were obstructed at 9 cmH(2)O CPAP., Conclusions: This study suggests that 6 cmH(2)O CPAP effectively improved arterial oxygenation without interference of the surgical field during OLV when CPAP was applied from 0 cmH(2)O in 3 cmH(2)O increments.

Breast surgery is a common procedure performed in women. Many women who undergo breast surgery suffer from ill-defined pain syndromes. A nerve block is used in the treatment of the acute and chronic pain, but the effectiveness of the treatment has been limited because of its short duration. Recently, the advent of pulsed radiofrequency lesioning (PRF) has proved a successful treatment for chronic refractory pain involving the peripheral nerves. We experienced a case of a 52-year-old female patient complaining of chronic breast neuropathic pain after breast reduction, which was relieved after PRF lesioning of the 4th thoracic spinal nerve and its root.

Background: When applying pulsed radiofrequency on dorsal root ganglia for treating chronic lower back pain, maximum efficiency can be expected when a needle is placed 1-2 cm peripheral to the dorsal root ganglion. The object of this study is to analyze images taken after adding contrast to transforaminal epidural injection, categorize root ganglia according to anatomical position, and provide a reference for efficient needle positioning in applying pulsed radiofrequency on dorsal root ganglia., Methods: From January 2008 to January 2009, 457 patients who visited our hospital for root pain or radiculopathy were treated with transforaminal epidural injection on the nerve roots based on the dermatome of the painful area. Anteroposterior views were taken after injection of contrast. A virtual line was made by connecting the internal and external parts of the spinal pedicle from the contrast images. Then the dorsal root ganglia were categorized as intraspinal (IS), intraforaminal (IF), or extraforaminal (EF)., Results: In the fourth lumbar spine, dorsal root ganglia positions were 48% IF, 41% IS, and 6% EF. In the fifth lumbar spine, dorsal root ganglia positions were 75% IF, 10% IS, and 6% EF. In the first sacral spine, dorsal root ganglia locations were 8% IF and 83% IS., Conclusions: Positional categorization of dorsal root ganglia according to contrast images was proven to be good anatomical references for effective radiofrequency or blocking of dorsal root ganglia.