Effect of Dexmedetomidine Preconditioning on Hepatic Ischemia-Reperfusion Injury in Acute Hyperglycemic Rats.

BACKGROUND: Acute hyperglycemia frequently occurs in stressful situations, including liver transplantation or hepatic surgery, which may affect the protective effects of dexmedetomidine preconditioning and increase postoperative mortality. Therefore, this study aimed to investigate the effects of dexmedetomidine on hepatic ischemia-reperfusion injury in acute hyperglycemia. METHODS: Thirty-six Sprague-Dawley rats were randomly assigned to 6 groups, including a combination between 2 glycemic (normo- and hyperglycemia) and 3 ischemia-reperfusion conditions (sham, ischemia-reperfusion only, and dexmedetomidine plus ischemia-reperfusion). Dexmedetomidine 70 µg/kg was preconditioned 30 minutes before ischemic injury. After 6 hours of reperfusion, serum aminotransferase levels were measured to confirm the hepatic tissue injury. Furthermore, inflammatory (nuclear factor-κb, tumor necrosis factor-α, and interleukin-6) and oxidative stress markers (malondialdehyde and superoxide dismutase) were detected. RESULTS: Ischemia-reperfusion injury significantly increased the serum levels of aminotransferase and inflammatory and oxidative stress markers. These ischemia-reperfusion-induced changes were further exacerbated in hyperglycemia and were significantly attenuated by dexmedetomidine preconditioning. However, the effects of dexmedetomidine in hyperglycemia were lesser than those in normoglycemia (P < .05 for aminotransferases, inflammatory markers, malondialdehyde, and superoxide dismutase). CONCLUSIONS: These findings suggest that the protective effects of dexmedetomidine preconditioning may be intact against hepatic ischemia-reperfusion injury in acute hyperglycemia. Although its effects appeared to be relatively reduced, this may be because of the increase in oxidative stress and inflammatory response caused by acute hyperglycemia. To determine whether the effects of dexmedetomidine itself would be impaired in hyperglycemia, further study is needed.

Superior laryngeal nerve block for treatment of throat pain and cough following laryngeal herpes zoster: A case report.

BACKGROUND: Herpes zoster is caused by reactivation of latent varicella-zoster virus infection within the sensory nerve ganglion of the spinal or cranial nerves. Laryngeal herpes zoster is rare and involves superior laryngeal nerve, which leads to several complications such as throat pain, and cough. CASE SUMMARY: Patient concerns: A 52-year old woman presented with a 70 d history of throat pain and a 67 d history of non-productive cough. Three days after onset of pain, she was diagnosed with laryngeal herpes zoster. Flexible nasolaryngoscopy revealed multiple white ulcerated lesions on the left hemi epiglottis and the left supraglottic area. She was prescribed with 750 mg famciclovir a day for 7 d, and 150 mg pregabalin, 100 mg tramadol and 10 mg nortriptyline a day for 67 d. However, despite of these medications, she complained of pain and persistent cough. Therefore, superior laryngeal nerve block under ultrasound guidance was performed. Three days after the intervention, the throat pain and cough disappeared. The patient remained symptom-free at 3 mo follow-up. CONCLUSION: A superior laryngeal nerve block can be an effective option for treatment of pain and cough following laryngeal herpes zoster.

Effect of Minimum Bronchial Cuff Volume of Left-Sided Double-Lumen Tube for One-Lung Ventilation on the Change in Bronchial Cuff Pressure during Lateral Positioning in Thoracic Surgery: A Prospective Observational Study.

The minimum bronchial cuff volume (BCVmin) of a double-lumen tube (DLT) without air leaks during lung isolation may vary among individuals, and lateral positioning could increase the bronchial cuff pressure (BCP). We investigated the effect of initially established BCVmin (BCVi) on the change in BCP by lateral positioning. Seventy patients who underwent elective lung surgery were recruited and divided into two groups according to the BCVi obtained during anesthetic induction in each patient. Outcome analysis was conducted using data from 39 patients with a BCVi greater than 0 (BCVi > 0 group) and 27 with a BCVi of 0 (BCVi = 0 group). The primary outcome was a change in the value measured in the supine and lateral positions of the initially established BCP (BCPi; BCP at the time of BCVi injection), which was significantly larger in the BCVi > 0 group than in the BCVi = 0 group (1.5 (0.5-6.0) cmH2O vs. 0.0 (0.0-1.0) cmH2O; p < 0.001). BCVi was related to the left main bronchus (LMB) diameter (Spearman's rho = 0.676, p < 0.001) and the gap between the LMB diameter and the outer diameter of the bronchial cuff (Spearman's rho = 0.553, p < 0.001). Therefore, selecting a DLT size with a bronchial cuff that fits each patient's LMB may be useful in minimizing the change in BCP when performing lateral positioning during thoracic surgery. If the bronchial cuff requires unavoidable initial inflation, it is necessary to be aware that BCP may increase during lateral positioning and to monitor the BCP regularly if possible.

Pressure changes in tapered and cylindrical shaped cuff after extension of head and neck: A randomized controlled trial.

BACKGROUND: The proper cuff pressure of endotracheal tube (ET) plays an important role in sealing the airway and preventing airway complications during mechanical ventilation. The ET cuff shape affects the cuff pressure after positional change. AIM: To investigate cuff pressure between tapered and cylindrical cuff after extension of head and neck during nasal endotracheal intubation. METHODS: In a randomized clinical trial, 52 patients were randomized to one of two groups: cylindrical cuff or Tapered cuff. Cuff pressure with 22 cmH2O was applied to patients in the neutral position. After extension of head and neck, the cuff pressure was evaluated again and readjusted to 22 cmH2O. In addition, the extent of cephalad migration of ET tip was assessed and postoperative airway complications such as sore throat, and hoarseness were measured. RESULTS: The cuff pressure was higher in the tapered cuff (28.7 ± 1.0 cmH2O) than in the cylindrical cuff (25.5 ± 0.8 cmH2O) after head and neck extension (P < 0.001). The extent of cephalad migration of tube tip was greater in TaperGuard ET (18.4 ± 2.2 mm) than in conventional ET (15.1 ± 1.2 mm) (P < 0.001). The incidence of postoperative airway complications was comparable between two groups. CONCLUSION: After head and neck extension, the cuff pressure and the extent of cephalad migration of ET was greater in tapered cuff than in cylindrical cuff during nasal intubation, respectively.

Monitored anesthesia care for craniotomy in a patient with Eisenmenger syndrome: A case report.

BACKGROUND: Eisenmenger syndrome (ES) is an uncorrected congenital cardiac defect with a left-to-right shunt, leading to pulmonary arterial hypertension. Patients with ES are susceptible to hemodynamic alterations during noncardiac surgery with general anesthesia, which increases perioperative morbidity and mortality. Monitored anesthesia care (MAC) is often used during minor procedures in patients with cardiac disease. However, few reports on MAC in patients with ES exist. CASE SUMMARY: A 49-year-old man was admitted for a severe headache lasting 30 d. He had been diagnosed with a large perimembranous ventricular septal defect (VSD) with bidirectional shunt flow and pulmonary arterial hypertension 10 years ago. A round mass in the right frontal lobe was revealed by Magnetic resonance imaging. Stereotactic aspiration using a neuronavigation system was performed under MAC. The patient was stayed in the hospital for 5 d, and discharged without complications. CONCLUSION: MAC may be effective for craniotomy in patients with ES.

Transcutaneous electrical nerve stimulation for pain during propofol injection: a randomized clinical trial.

Background: Propofol is a short-acting intravenous sedative widely used for procedural sedation and general anesthesia. However, pain during propofol injection is a distressing adverse effect. This study was designed to investigate whether transcutaneous electrical nerve stimulation (TENS) could reduce pain during propofol injection compared to sham TENS. Methods: In a randomized controlled trial, 80 patients were allocated to two groups: the active TENS group received electrical stimulation via two electrodes on the venous cannulation site, whereas the sham TENS group received no stimulus. After 20 min following TENS, propofol 0.5 mg/kg pain was injected intravenously and pain was evaluated using a four-point score (0 = none, 1 = mild, 2 = moderate, 3 = severe). Adverse effects associated with TENS were also recorded. Results: The overall incidence of pain during propofol injection was 47.5% in the TENS group and 87.5% in the sham group (P < 0.001). The incidence of moderate pain was significantly lower in the TENS group (7.5%) than in the sham TENS group (42.5%) (P < 0.001). There were no complications associated with TENS. Conclusion: Pre-treatment with TENS significantly reduced the incidence and intensity of pain during propofol injection.

Anesthetic experience: congenital methemoglobinemia due to hemoglobin M.

Methemoglobinemia is rare. It is classified into two types: congenital methemoglobinemia and acquired methemoglobinemia. Methemoglobin is incapable of binding oxygen, leading to complications such as cyanosis, dyspnea, headache, and heart failure. In the present case, a 35-year-old man with congenital methemoglobinemia underwent general anesthesia for thyroidectomy. The patient was diagnosed with hemoglobin M at 7 years of age. Ventilation was performed with FiO2 1.0. Arterial blood gas analysis showed that the pH was 7.4, PaO2 439 mmHg, PaCO2 40.5 mmHg, oxyhemoglobin level of 83.2%, and methemoglobin level of 15.5%. The patient had a stable course, although cyanosis was observed during surgery.

The Role of Dexmedetomidine in Hepatic Ischemia-Reperfusion Injury Via a Nitric Oxide-Dependent Mechanism in Rats.

BACKGROUND: Dexmedetomidine is known to protect against ischemia-reperfusion (IR) in various organs; however, the mechanisms of dexmedetomidine in the liver remain unclear. We investigated whether dexmedetomidine preconditioning leads to hepatic protection and whether nitric oxide was associated with this protective mechanism by employing N-nitro-l-arginine methyl ester (l-NAME), a nitrous oxide synthase inhibitor. METHODS: Experiment 1 included 24 rats in 4 groups: sham, IR, 30 µg/kg of dexmedetomidine, and 50 µg/kg of dexmedetomidine. Experiment 2 included 36 rats in 6 groups: IR, 50 µg/kg of dexmedetomidine, 10 mg/kg of l-NAME, 10 mg/kg of l-NAME + 50 µg/kg of dexmedetomidine, 30 of mg/kg l-NAME, and 30 mg/kg of l-NAME + 50 µg/kg of dexmedetomidine. All drugs were administered intraperitoneally. The levels of serum transaminases, malondialdehyde, superoxide dismutase, tumor necrosis factor-α, nuclear factor-κB, and c-Jun N-terminal kinase were measured 6 hours after hepatic surgery. RESULTS: Dexmedetomidine demonstrated a dose-dependent decrease in serum transaminase levels. The 50-µg/kg dexmedetomidine group showed a significant decrease in malondialdehyde levels (P = .002), increase in superoxide dismutase levels (P = .002), and a significantly lower level of phosphorylated tumor necrosis factor-α, nuclear factor-κB, and c-Jun N-terminal kinase (P = .002, respectively) compared with the IR injury group. These protective effects of dexmedetomidine were partially reversed by pretreatment with l-NAME (P < .01 for 20 and 30 mg/kg of l-NAME). CONCLUSION: In hepatic IR injury, dexmedetomidine might protect the liver via antioxidative and anti-inflammatory responses, and nitric oxide production could play a role in these protective mechanisms.

Comparison of Whitacre needle and Chiba needle on the incidence of intravascular injection during caudal epidural injections: A single-blind, randomized clinical consort study.

ABSTRACT: Caudal epidural injection (CEI) is effective for lumbar spinal pain. However, accidental intravascular injection reduces therapeutic efficacy of CEI and leads to fatal complications such as hematoma, and neurologic deficit. Whitacre needle has been reported to be effective for reducing intravascular injection during transforaminal epidural injection, compared with Quincke needle. The bevel of Chiba needle is shorter than that of Quincke needle. In this study we compared Whitacre needle and Chiba needle on incidence of intravascular injection during CEI.This was a single-blind, randomized clinical consort study. After institutional Review Board approval, a total of 164 patients underwent CEI were randomly allocated to one of 2 group (Whitacre needle or Chiba needle group). Intravascular injection was assessed with real-time fluoroscopy. In addition, total procedure time was measured. Data were compared between groups, and P < .05 was consideredstatistically significant.There were no differences between groups in terms of patient demographic and clinical characteristics. There was no significant difference on incidence of intravascular injection between Whitacre and Chiba needle group (11% vs 19.5%, P = .192). However, the procedure time is significantly longer in the Whitacre than Chiba needle group (172.8 ±â€Š53.8 sec vs 147.1 ±â€Š61.1 sec, P = .005).Based on current study, our results indicated that Whitacre needle was not effective to decrease the incidence of intravascular injection during CEI, compared to Chiba needle.

Efficacy and Safety of the Controlled-release Pregabalin Tablet (GLA5PR GLARS-NF1) and Immediate-release Pregabalin Capsule for Peripheral Neuropathic Pain: A Multicenter, Randomized, Double-blind, Parallel-group, Active-controlled, Phase III Clinical Trial.

PURPOSE: This study compared the efficacy and safety of controlled-release pregabalin (GLA5PR GLARS-NF1 tablets) with those of an immediate-release pregabalin capsule after 12 weeks' administration to patients with peripheral neuropathic pain. METHODS: In this multicenter, randomized, double-blind, active-controlled, parallel-group, Phase III study, the primary outcome was to confirm that a single treatment with the study drug (after the evening meal) is clinically noninferior to the control drug (BID regimen) at improving the mean Daily Pain Rating Scale score for treating peripheral neuropathic pain. Secondary outcomes were the Daily Sleep Interference Scale, Medical Outcomes Study Sleep Scale, Hospital Anxiety and Depression scale, and frequency of rescue medication use. The safety and tolerability of GLA5PR GLARS-NF1 tablets were also evaluated. The total daily dose of pregabalin is 150-600 mg. FINDINGS: Of the 352 randomized subjects, 261 (n = 130, study group; n = 131, control group) were analyzed. The difference in adjusted mean Daily Pain Rating Scale scores between the groups was -0.11 (95% confidence interval, -0.05 to 0.30), indicating that the study group is noninferior to the control group. There was no statistically significant difference in Daily Sleep Interference Scale, Medical Outcomes Study Sleep Scale, and Hospital Anxiety and Depression scale scores between the groups at treatment termination. Logistic regression analysis revealed no significant difference in the use of rescue medication between the groups (P = 0.217). The overall adverse event profile of the groups was similar, and no serious adverse drug reactions were observed. IMPLICATIONS: GLA5PR GLARS-NF1 tablets can be effectively and safely administered to patients with peripheral neuropathic pain. Furthermore, we found that sleep, anxiety, and depression were improved with pain control. Owing to the once-daily administration, treatment effects can be maximized by improved treatment compliance. ClinicalTrials.gov identifier: NCT03221907.

Fibromyalgia: practical considerations for oral health care providers.

Fibromyalgia is a syndrome characterized by chronic pain in the skeletal system accompanied by stiffness, sleep disturbance, fatigue, and psychiatric problems, such as anxiety and depression. Fibromyalgia commonly affects orofacial health, presenting with a variety of oral manifestations, including temporomandibular disorder, xerostomia, glossodynia, and dysgeusia. Therefore, oral healthcare providers need to be aware of this clinical entity to effectively manage oral symptoms and provide proper oral self-care modification and education on the nature of fibromyalgia. This review focuses on the epidemiology, pathophysiology, clinical manifestation, diagnosis, orofacial concerns, and treatment of fibromyalgia.

Transient facial paralysis after myringotomy and ventilation tube insertion under sedation with sevoflurane inhalation and four-quadrant blocks with lidocaine: a case report.

Myringotomy and ventilation tube insertion are widely performed in pediatric patients with chronic otitis media. This procedure is performed under general anesthesia or sedation with local anesthesia infiltration in pediatric patients. In this case report, we report a case of transient facial paralysis in a pediatric patient who underwent myringotomy and ventilation tube insertion using sevoflurane inhalation and four-quadrant blocks with lidocaine.

Caudal block with steroid in the treatment of acute voiding dysfunction and pain caused by sacral herpes zoster: A case report.

RATIONALE: Herpes zoster (HZ) involving sacral dermatome is very rare, which can sometimes cause voiding dysfunction. PATIENT CONCERNS: A 52-year-old man presented with acute pain and voiding dysfunction, following HZ in his right sacral dermatomes. DIAGNOSES: Twenty two days before presentation HZ occurred and 9 days after the onset of the HZ, he had trouble with starting urination and weak urine stream which was managed with tamsulosin 0.4 mg orally once a day and intermittent urinary catheterization. He was treated with 150 mg of pregabalin 2 times a day, tramadol 50 mg 2 times, and acetaminophen 600 mg 2 times a day. However, his pain intensity was 5 on the numerical analogue scale (NRS) from 0 (no pain) to 10 (worst pain imaginable). INTERVENTIONS: Fluoroscopy guided caudal block was performed with a mixture of 0.5% lidocaine 10 mL and triamcinolone 40 mg. OUTCOMES: One day after the procedure, the pain decreased to 1 on the NRS score. In addition, voiding difficulty greatly improved. Three days after the intervention, the patient reported complete resolution of pain and voiding dysfunction. He currently remains symptom free at a 3-month follow-up. LESSONS: A caudal block with steroid can be an effective option for treatment of acute voiding dysfunction and pain following sacral HZ.

Junctional rhythm with severe hypotension following infiltration of lidocaine containing epinephrine during dental surgery.

We experienced an unusual case of accelerated junctional rhythm with severe hypotension after infiltration of lidocaine containing epinephrine during dental surgery under general anesthesia. The patient's electrocardiogram exhibited retrograde P-waves following the QRS complex, which could be misinterpreted as ST-segment depression. As a temporary measure, administration of ephedrine restored the patient's blood pressure to normal levels. The importance of this case lies in its demonstration of an unexpected and serious side effect of commonly used epinephrine infiltration. This case also highlights the need for accurate interpretation of the electrocardiogram and comprehensive understanding of best practices for patient management.

Bilateral stellate ganglion block for migraine: A case report.

RATIONALE: Migraine is a recurrent, disabling neurovascular headache disorder. The patient's quality of life can be severely impaired by migraine attacks. Stellate ganglion block (SGB) can be used to relieve pain in the head, neck, and upper extremities. In the present cases, we performed SGB in 2 patients with migraine that responds poorly to drugs. PATIENT CONCERNS: Patients 1 and 2 suffered from chronic, bilateral pulsating headache, accompanied by nausea and vomiting. Patient 1 presented with headache of 8 on the visual analog scale (VAS), and 37 on the migraine disability assessment (MIDAS). Patient 2 reported headache of 7 on the VAS, and 32 on the MIDAS. DIAGNOSIS: The patients were diagnosed with migraine without aura based on the International Classification of Headache Disorders version 3. INTERVENTIONS: Patient 1 was treated with bilateral SGB every week for a month and then every month for 3 months. Patient 2 received bilateral SGB every 2 weeks for a month and then every month for 3 months. OUTCOMES: Four months after SGB, patient 1 reported pain intensity of 4 on VAS and 6 on MIDAS and patient 2 rated pain intensity of 3 on VAS, and 6 on MIDAS, respectively. LESSONS: The SGB can be an effective option to improve headache-related disability and relieve pain intensity in the patients with refractory migraine.

Comparison of Intravascular Injection Rate Between Blunt and Sharp Needles During Cervical Transforaminal Epidural Block.

BACKGROUND: Cervical transforaminal epidural block (CTEB) is a useful option in the diagnosis and treatment of cervical radicular pain. However, inadvertent intravascular injection can lead to severe neurologic complications. Blunt needles are considered to displace instead of penetrate vessels because of their dull needle tip. OBJECTIVES: To investigate whether there is a difference between blunt and sharp needles in intravascular injection rates during CTEB. STUDY DESIGN: Prospective, randomized, clinical trial. SETTING: A tertiary hospital in South Korea. METHODS: After institutional review board approval, 108 patients undergoing CTEB for treatment of radicular pain resulting from spinal stenosis and herniated nucleus pulposus were randomly assigned to one of 2 needle groups (blunt needle or sharp needle). The needle position was confirmed using biplanar fluoroscopy, and 2 mL of nonionic contrast medium was injected to detect intravascular injection. Intravascular injection was defined as the contrast medium spreading out through the vascular channel during injection under real-time fluoroscopy. This study was registered in ClinicalTrials.gov. RESULTS: The intravascular injection rate was not significantly different between the blunt needle and sharp needle groups (35.2% vs. 33.3%, P > 0.05). The procedure time was longer in the blunt needle group than in the sharp needle group (101.00 ± 12.4 seconds vs. 56.67 ± 8.3 seconds, P < 0.001). LIMITATIONS: This was a single-center study. Additionally, the physicians could not be blinded to the type of needle used. CONCLUSIONS: In the present study, use of a blunt needle did not reduce the rate of intravascular injection during CTEB compared to use of a sharp needle. In addition, procedure time significantly increased with blunt needle use compared to sharp needle use. KEY WORDS: Analgesia, bleeding, blunt needle, cervical spine, clinical trials, complications, intravascular injection, radiculopathy, sharp needle, transforaminal epidural block.

The Effect of Nitric Oxide on Remote Ischemic Preconditioning in Renal Ischemia Reperfusion Injury in Rats.

Although remote ischemic preconditioning (RIPC) is an organ-protective maneuver from subsequent ischemia reperfusion injury (IRI) by application of brief ischemia and reperfusion to other organs, its mechanism remains unclear. However, it is known that RIPC reduces the heart, brain, and liver IRI, and that nitric oxide (NO) is involved in the mechanism of this effect. To identify the role of NO in the protective effect of RIPC in renal IRI, this study examined renal function, oxidative status, and histopathological changes using N-nitro-L-arginine methyl ester (L-NAME), an NO synthase inhibitor. Remote ischemic preconditioning was produced by 3 cycles of 5 minutes ischemia and 5 minutes reperfusion. Blood urea nitrogen, creatinine (Cr), and renal tissue malondialdehyde levels were lower, histopathological damage was less severe, and superoxide dismutase level was higher in the RIPC + IRI group than in the IRI group. The renoprotective effect was reversed by L-NAME. Obtained results suggest that RIPC before renal IRI contributes to improvement of renal function, increases antioxidative marker levels, and decreases oxidative stress marker levels and histopathological damage. Moreover, NO is likely to play an important role in this protective effect of RIPC on renal IRI.

Dexamethasone treatment for bilateral lingual nerve injury following orotracheal intubation.

Lingual nerve injury is a rare complication of general anesthesia. The causes of lingual nerve injury following general anesthesia are multifactorial; possible mechanisms may include difficult laryngoscopy, prolonged anterior mandibular displacement, improper placement of the oropharyngeal airway, macroglossia and tongue compression. In this report, we have described a case of bilateral lingual nerve injury that was associated with orotracheal intubation for open reduction and internal fixation of the left distal radius fracture in a 61-year-old woman. In this case, early treatment with dexamethasone effectively aided the recovery of the injured lingual nerve.

Detection of Intravascular Injection During Cervical Transforaminal Epidural Injection: A Comparison of Digital Subtraction Angiography and Real Time Fluoroscopy.

BACKGROUND: Transforaminal epidural injection (TFEI) with local anesthetics and steroids are effective in treating spinal radicular pain. However, inadvertent intravascular injection can lead to severe neurologic complications. To reduce complications of intravascular injection, use of imaging modality, such as real-time fluoroscopy (RTF) or digital subtraction angiography (DSA), has been recommended. DSA is an imaging technique that can clearly visualize the blood vessels from surrounding bones or dense soft tissues by subtracting the pre-contrast image from the image after injecting contrast medium. OBJECTIVE: In this study, we investigated whether there is a difference between RTF and DSA in the detection of intravascular injection during cervical TFEI. STUDY DESIGN: Clinical study. SETTING: Pain clinic in South Korea. METHODS: We prospectively examined 137 cervical TFEIs on 128 patients who have a radiating pain from spinal stenosis and herniated nucleus pulposus. The needle position was confirmed using biplanar fluoroscopy and 2 mL of nonionic contrast medium was injected at the rate of 0.5 mL/sec under RTF. Thirty seconds later, 2 mL of nonionic contrast medium was injected at the rate of 0.5 mL/sec under DSA. Intravascular injection was defined as contrast medium spreading throughout the vascular channel during injection of contrast medium under RTF and DSA. This study is registered in the ClinicalTrials.gov (NCT03040648). RESULTS: The detection rate of intravascular injection in RTF was not statistically different compared to that in DSA (30.7 % vs. 34.3%, P > 0.05). LIMITATIONS: We injected 2 mL of contrast medium at the rate of 0.5 mL/sec. Further studies about the ideal injection speed and volume of contrast medium for improvement of detection of intravascular injection during TFEI are needed. This study was a single center study. Therefore, multi-center studies are needed to obtain the high level of evidence. Additionally, the procedural pain physician was not blinded to the type of imaging modality, such as RTF and DSA, to detect intravascular injection. To minimize this confirmation bias and provide homogenous procedural conditions for TFEI, the same procedural physician performed all 137 injections. CONCLUSIONS: In this study, there is no significant difference in detection rate of intravascular injection between RTF and DSA during cervical TFEI. KEY WORDS: Analgesia, bleeding, clinical trials, complications, diagnostic equipment, epidural, radiculopathy, spine.

Cold Allodynia after C2 Root Resection in Sprague-Dawley Rats.

OBJECTIVE: The purpose of this study was to evaluate pain-related behaviors after bilateral C2 root resection and change in pain patterns in the suboccipital region in rats. METHODS: Male Sprague-Dawley rats were randomly assigned to three groups (n=25/group); näive, sham, and C2 resection. Three, 7, 10, and 14 days after surgery, cold allodynia was assessed using 20 µL of 99.7% acetone. c-Fos and c-Jun were immunohistochemically stained to evaluate activation of dorsal horn gray matter in C2 segments of the spinal cord 2 hours, 1 day, 7 days, and 14 days after surgery. RESULTS: Three days after surgery, the response to acetone in the sham group was significantly greater than in the näive group, and this significant difference between the näive and sham groups was maintained throughout the experimental period (p<0.05 at 3, 7, 10, and 14 days). Seven, 10, and 14 days after surgery, the C2 root resection group exhibited a significantly greater response to acetone than the näive group (p<0.05), and both the sham and C2 resection groups exhibited significantly greater responses to acetone compared with 3 days after surgery. No significant difference in cold allodynia was observed between the sham and C2 root resection groups throughout the experimental period. Two hours after surgery, both the sham and C2 root resection groups exhibited significant increases in c-Fos- and c-Jun-positive neurons compared with the naive group (p=0.0021 and p=0.0358 for the sham group, and p=0.0135 and p=0.014 for the C2 root resection group, respectively). One day after surgery, both the sham and C2 root resection groups exhibited significant decreases in c-Fos -positive neurons compared with two hours after surgery (p=0.0169 and p=0.0123, respectively), and these significant decreases in c-Fos immunoreactivity were maintained in both the sham and C2 root resection groups 7 and 14 days after surgery. The sham and C2 root resection groups presented a tendency toward a decrease in c-Jun-positive neurons 1, 7, and 14 days after surgery, but the decrease did not reach statistical significance. CONCLUSION: We found no significant difference in cold allodynia and the early expression of c-Fos and c-Jun between the sham and C2 resection groups. Our results may support the routine resection of the C2 nerve root for posterior C1-2 fusion, but, further studies are needed.