New Trigeminal Stimulation Technique with Dorsal Root Ganglion Stimulation Electrode and Maxillary Fixation: Technique Description

BACKGROUND

Trigeminal neuralgia is considered the worst pain a human being can experience. Initial treatment uses anticonvulsant sodium channel blockers, which relieve pain in approximately 70% of patients. In refractory cases, it is possible to perform ablative treatments, decompressive surgeries, and neuromodulatory techniques.

METHODS

This report describes the treatment of a patient with refractory trigeminal neuralgia who continued to have a painful clinical presentation after four surgical procedures and three ablative procedures. The patient presented with severe pain (verbal numerical scale between 9 and 10), manifesting an evident suicidal ideation. A dorsal root ganglion (DRG) stimulation electrode was implanted in the trigeminal ganglion through intraoral puncture with maxillary fixation of the electrode, in order to minimize the chances of displacement. The test phase consisted of implanting a quadripolar electrode for DRG stimulation through puncture lateral to the buccal rim in a fluoroscopic coaxial view. The electrode was fixed to the skin and maintained for 5 days, during which the patient remained completely pain free. After the 5-day test period, the definitive stimulation electrode was implanted, this time with intraoral puncture and maxillary electrode fixation.

RESULTS

The patient remains pain free in the 3-month follow-up, with no displacement of the electrode.

CONCLUSIONS

The DRG electrode may be considered a therapeutic option in patients with severe trigeminal neuralgia. Controlled studies must be performed to determine the efficacy and safety of the method.

Percutaneous Radiofrequency Ablation for Trigeminal Neuralgia Management: A Randomized, Double-Blinded, Sham-Controlled Clinical Trial

Trigeminal neuralgia, considered by many the worst pain that humankind can experience, has been called "the suicide disease." Neuroablative procedures are good options when conservative treatment fails to promote pain relief or in those whose side effects are unbearable. The objective was to compare the effectiveness and safety of trigeminal percutaneous radiofrequency ablation in classical refractory trigeminal neuralgia in a prospective, randomized, double-blind, sham-controlled clinical trial. We included 30 consecutive patients with classical trigeminal neuralgia who had failed to respond to drug treatment. The patients were randomly assigned into two groups: a thermal radiofrequency and a sham group. The thermal radiofrequency group were submitted to a 75°C lesion for 60 seconds after proper sensory and motor stimulation. All steps were carried out in the sham group except the thermal lesion. Patients were evaluated using the Numerical Rating Scale (NRS), the 36-Item Short-Form Health Survey questionnaire, and anticonvulsant dose. After 1 month, the mean NRS score decreased from 9.2 to 0.7 in the radiofrequency group and from 8.9 to 5.8 in the sham group. This significant reduction was measurable starting at day one after the procedure and remained significant throughout the first month. Changing groups was allowed after one month, after which the pain reduction was similar between the two groups. Percutaneous trigeminal radiofrequency ablation results in statistically and clinically significant greater pain relief than the sham procedure after 1 month of follow-up. These results support using radiofrequency nerve ablation as a treatment for refractory trigeminal neuralgia.

Bedside tests to predict laryngoscopic difficulty in pediatric patients

BACKGROUND AND OBJECTIVES

Pediatric airway management is a priority during anesthesia, critical care and emergency medicine. The purpose of this study is to validate bedside tests that predict airway management difficulty in anesthetized children.

METHODS

Children under 12 years of age were recruited in a cross-sectional study to assess the value of some anthropometric measures as predictors of laryngoscopic difficulty. The patients were divided into three groups by age. Weight, height, neck circumference, BMI (body mass index), inter incisors distance thyromental distance, sternomental distance, frontal plane to chin distance (FPCD) and the Mallampati index were determined and were correlated with the CML (Cormack & Lehane classification).

RESULTS

The incidence of difficult laryngoscopy (CML 3 or 4) was 3.58%. Factors that were significantly associated with laryngoscopic difficulty included short inter incisors distance, high FPCD, thyromental distance, sternomental distance and the Mallampati index. The FPCD/weight index exhibited a higher area under the ROC curve than any other variable considered.

CONCLUSIONS

This study confirms that the FPCD and the FPCD/weight ratio are the most consistent predictors of laryngoscopic difficulty in pediatric patients. For patients over 6 months of age, the IID also correlated with laryngoscopic difficulty. For children who were capable of obeying simple orders, the Mallampati test correlated better with laryngoscopic difficulty than did the Mallampati test with phonation. Our results strongly suggest that skilled professionals should perform airway management in children, especially in patients with a high FPCD or a high FPCD/weight ratio.

Prevention of renal ischemia/reperfusion injury in rats using acetylcysteine after anesthesia with isoflurane

PURPOSE: To evaluate the effect of N-acetylcysteine, as a renoprotective agent, when administered early after anesthesia induction, against ischemia/reperfusion injury in rats anesthetized with isoflurane. METHODS: Eighteen male Wistar rats weighing > 300g were anesthetized with isoflurane. The internal jugular vein and the left carotid artery were dissected and cannulated. The animals were randomly divided into GAcetyl, receiving intravenous N-acetylcysteine, 300mg/kg, and GIsot, isotonic saline. After 30 minutes, right nephrectomy was performed and the left renal artery was clamped during 45 minutes. The animals were sacrificed after 48 hours and blood samples were taken after anesthetic induction and upon sacrificing of the animals to evaluate blood creatinine. The kidneys were sent for histological analysis. RESULTS: The variation in serum creatinine was 2.33mg/dL ± 2.21 in GAcetyl and 4.38mg/dL ± 2.13 in GIsot (p=0.074). Two animals presented intense tubular necrosis in GAcetyl, compared to 5 in GIsot. Only GAcetyl presented animals free of tubular necrosis (two) and tubular degeneration (one). CONCLUSION: After renal ischemia/reperfusion, the rats which were given N-acetylcysteine presented less variation in serum creatinine and milder kidney injuries than the control group.