Clinical results of lumbar sympathetic blocks in lower limb complex regional pain syndrome using infrared thermography as a support tool.

AIM: To describe the clinical outcomes for a group of complex regional pain syndrome patients using infrared thermography as an intraprocedural support tool when undertaking fluoroscopy-guided lumbar sympathetic blocks. SUBJECTS: 27 patients with lower limb complex regional pain syndrome accompanied by severe pain and persistent functional impairment. METHODS: A series of three fluoroscopic-guided lumbar sympathetic blocks with local anesthetic and corticoids using infrared thermography as an intraprocedural support tool were performed. Clinical variables were collected at baseline, prior to each block, and one, three, and six months after blocks in a standardized checklist assessing each of the clinical categories of complex regional pain syndrome stipulated in the Budapest criteria. RESULTS: 23.75% of the blocks required more than one chance to achieve the desired thermal pattern and therefore to be considered as successful. A decrease in pain measured on a visual analogic scale was observed at all time points compared to pre-blockade data, but only 37% of the cases were categorized as responders, representing a ≥ 30% decrease in VAS, with the disappearance of pain at rest. An improvement of most of the clinical variables recorded was observed, such as tingling, edema, perception of thermal asymmetry, difference in coloring and sweating. There was a significant decrease of neuropathic pain and improvement of functional limitation. Logistic regression analysis showed the main variable to explain the probability of being a responder was immobilization time (odds ratio of 0.89). CONCLUSION: A series of fluoroscopy-guided lumbar sympathetic blocks controlled by infrared thermography in the treatment of lower limb CRPS showed a responder rate of 37%.

Application of machine learning algorithms in thermal images for an automatic classification of lumbar sympathetic blocks.

PURPOSE: There are no previous studies developing machine learning algorithms in the classification of lumbar sympathetic blocks (LSBs) performance using infrared thermography data. The objective was to assess the performance of different machine learning algorithms to classify LSBs carried out in patients diagnosed with lower limbs Complex Regional Pain Syndrome as successful or failed based on the evaluation of thermal predictors. METHODS: 66 LSBs previously performed and classified by the medical team were evaluated in 24 patients. 11 regions of interest on each plantar foot were selected within the thermal images acquired in the clinical setting. From every region of interest, different thermal predictors were extracted and analysed in three different moments (minutes 4, 5, and 6) along with the baseline time (just after the injection of a local anaesthetic around the sympathetic ganglia). Among them, the thermal variation of the ipsilateral foot and the thermal asymmetry variation between feet at each minute assessed and the starting time for each region of interest, were fed into 4 different machine learning classifiers: an Artificial Neuronal Network, K-Nearest Neighbours, Random Forest, and a Support Vector Machine. RESULTS: All classifiers presented an accuracy and specificity higher than 70%, sensitivity higher than 67%, and AUC higher than 0.73, and the Artificial Neuronal Network classifier performed the best with a maximum accuracy of 88%, sensitivity of 100%, specificity of 84% and AUC of 0.92, using 3 predictors. CONCLUSION: These results suggest thermal data retrieved from plantar feet combined with a machine learning-based methodology can be an effective tool to automatically classify LSBs performance.

Human lumbar sympathetic blockade: An anatomical study to address potential block failure.

The lumbar sympathetic block is often used to treat complex regional pain syndrome, but it seems to have a high failure rate. This study seeks anatomical explanations for this apparent failure in order to refine our block procedure. Two simulated sympathetic trunk blocks were carried out on four fresh, cryopreserved unembalmed human cadavers under fluoroscopic control at the L2 vertebral body level, followed by two further simulated blocks at the L4 vertebral body level on the other side. Dye was injected, and the areas were dissected following a specific protocol. We then describe the anatomy and the spread of the dye compared to the spread of the contrast medium on fluoroscopy. The ganglia were differently located at different vertebral levels, and differed among the cadavers. Following this anatomical clarification, we now prefer to perform lumbar sympathetic blocks at the fourth lumbar vertebra level, using an extraforaminal approach at the caudal end of ​​the vertebra, avoiding the anterolateral margin of the vertebral body at the midpoint.

Skin Temperature Assessment During Lumbar Sympathetic Blocks by Infrared Thermography.

Complex Regional Pain Syndrome (CRPS) is a pain disorder that can be triggered by injuries or surgery affecting most often limbs. Its multifaceted pathophysiology makes its diagnosis and treatment a challenging work. To reduce pain, patients diagnosed with CRPS commonly undergo sympathetic blocks which involves the injection of a local anesthetic drug around the nerves. Currently, this procedure is guided by fluoroscopy which occasionally is considered as little accurate. For this reason, the use of infrared thermography as a technique of support has been considered.In this work, thermal images of feet soles in patients with lower limbs CRPS undergoing lumbar sympathetic blocks were recorded and evaluated. The images were analyzed by means of a computer-aided intuitive software tool developed using MATLAB. This tool provides the possibility of editing regions of interest, extracting the most important information of these regions and exporting the results data to an Excel file.Clinical Relevance- The final purpose of this work is to value the potential of infrared thermography and the analysis of its images as an intraoperatory technique of support in lumbar sympathetic blocks in patients with lower limbs CRPS.

Effect of the relative position of electrode and stellate ganglion during thermal radiofrequency ablation: a simulation study.

PURPOSE: Stellate ganglion (SG) block by thermal radiofrequency ablation (RFA) is frequently conducted as a therapeutic intervention for sympathetic-maintained and neuropathic pain syndromes. RFA's partial lack of effectiveness could be partly due to the ablation zone (AZ) not completely covering the SG section and therefore preventing the 'cutting' of the afferent pathways. Our objective was to build a theoretical model to conduct computer simulations to assess the effect of the electrode position relative to the SG. METHODS: A three-dimensional model was built including the SG and adjacent tissues (vertebrae C7-T1-T2, trachea, carotid artery and vertebral artery). RFA (90-s, 80 °C) was simulated considering a 22 G-5 mm electrode. The AZ was computed using the 50 °C isotherm. RESULTS: An electrode displacement of 2 mm in any direction from the optimal position (centered on the SG) meant that the AZ did not fully cover the SG section. Likewise, SG size considerably affected the RFA effectiveness since the AZ fully covered the section of small but not large SGs. CONCLUSIONS: The findings suggest that the currently used SG RFA settings (i.e., 22 G-5 mm electrode, 90-s, 80 °C) may not be appropriate due to their inability to achieve an AZ that fully covers the SG cross section under certain circumstances, such as a large SG and non-optimal positioning of the RF electrode with respect to the SG center.

Quantitative Analysis of Real-Time Infrared Thermography for the Assessment of Lumbar Sympathetic Blocks: A Preliminary Study.

Lumbar sympathetic blocks (LSBs) are commonly performed to treat pain ailments in the lower limbs. LSBs involve injecting local anesthetic around the nerves. The injection is guided by fluoroscopy which is sometimes considered to be insufficiently accurate. The main aim was to analyze the plantar foot skin temperature data acquired while performing LSBs in patients with complex regional pain syndrome (CRPS) affecting the lower limbs. Forty-four LSBs for treating lower limb CRPS in 13 patients were assessed. Pain medicine physicians visualized the infrared thermography (IRT) video in real time and classified the performance depending on the observed thermal changes within the first 4 min. Thirty-two percent of the cases did not register temperature variations after lidocaine was injected, requiring the needle to be relocated. Differences between moments are indicated using the 95% confidence intervals of the differences (CI 95%), the Cohen effect size (ES) and the significance (p value). In successful cases, after injecting lidocaine, increases at minute 7 for the mean (CI 95% (1.4, 2.1 °C), p < 0.001 and ES = 0.5), at minute 5 for maximum temperature (CI 95% (2.3, 3.3 °C), p < 0.001 and ES = 0.6) and at minute 6 for SD (CI 95% (0.2, 0.3 °C), p < 0.001 and ES = 0.5) were observed. The results of our preliminary study showed that the measurement of skin temperature in real time by infrared thermography is valuable for assessing the success of lumbar sympathetic blocks.

Preoperative Anxiety and Its Influence on Patient and Surgeon Satisfaction in Patients Receiving Dental Implant Surgeries Performed Under Intravenous Conscious Sedation.

PURPOSE: The aims of this study were to evaluate the relationship of age, sex, and type and duration of the surgery with preoperative anxiety in patients undergoing dental implant surgeries under intravenous conscious sedation, and to assess preoperative anxiety association with the postoperative satisfaction of both the patient and surgeon. MATERIALS AND METHODS: This prospective study included 180 patients receiving dental implant surgeries under intravenous conscious sedation by means of midazolam, fentanyl, and propofol. Preoperative anxiety (Corah Dental Anxiety Scale), number of implants, duration of surgery, surgeon satisfaction (evaluated as three categories: patient too awake and nervous, adequate sedation, or patient too asleep), and patient satisfaction (classified as five levels: agreeable, neither agreeable nor disagreeable, slightly uncomfortable, unpleasant, traumatic) were recorded. RESULTS: All 180 patients completed the study, and 72.2% of them experienced moderate or high levels of anxiety. The mean Corah scale score was 9.2 ± 3.5. Anxiety was significantly higher among men but showed no relation to age. A significant relationship was found between patient anxiety and the number of implants: those patients who received eight or more implants, with a duration of surgery longer than 60 minutes, had lower anxiety. Surgeon satisfaction was adequate in 90% of the cases. Patients evaluated the procedure as agreeable in 34.4% of cases, neither agreeable nor disagreeable in 26.7%, slightly uncomfortable in 29.4%, unpleasant in 7.8%, and traumatic in 1.7%. High anxiety levels were related with poor patient satisfaction but not with surgeon satisfaction. CONCLUSION: Preoperative anxiety was moderate or high in two-thirds of patients undergoing dental implant surgeries, having a negative influence on patient satisfaction, but not affecting surgeon satisfaction. Additionally, the intravenous conscious sedation technique was considered a satisfactory technique by the surgeon to control anxiety.

Conventional radiofrequency treatment in five patients with trigeminal neuralgia.

INTRODUCTION: In trigeminal neuralgia, when drug treatment proves ineffective, other management options must be considered. In this context, conventional radiofrequency of Gasser's ganglion is a safe and effective alternative. MATERIAL AND METHODS: We describe 5 patients with long-evolving trigeminal neuralgia subjected to conventional radiofrequency according to the Sweet technique, with a follow-up of two years. RESULTS: Pain relief was complete after two months in all cases. One patient suffered an unexpected episode of nausea, vomiting and foul odor sensation that subsided after three days of rest and drug treatment. Three patients described non-painful hypoesthesia in the region of the treated nerve branch that subsided within three months. The patients remained free of symptoms over long-term follow-up. In one case the same radiofrequency technique had to be repeated after 21 months because of the reappearance of symptoms in the same zone, followed by immediate pain relief. CONCLUSIONS: In our series of patients trigeminal neuralgia was not controlled by drug treatment, and conventional radiofrequency targeted to Gasser's ganglion proved very effective, with no major complications.

Radiofrequency treatment of cervicogenic headache.

OBJECTIVES: In the clinical management of facial pain, a possible cervical origin must be considered. A clinical exploration is therefore essential. The disorder originates in the intimate connections between the cranial portion of the spinal cord and the trigeminal system. Although solid evidence supporting the use of radiofrequency (RF) treatment is lacking, it remains one of the management options to be taken into account. The present study evaluates the efficacy of RF in application to cervicogenic headache. STUDY DESIGN: We present three cases of severe facial pain arising from different cervical structures. RESULTS: In two cases the pain originated in cervical roots C2 and C3, while in the third patient the trigger point was located at the level of the atlantoaxial joint. Pulsed RF was applied for 4 minutes at the dorsal ganglion of C2 and C3 in the first two cases, and for 8 minutes at intraarticular level in the third patient. The pain gradually subsided during the first month in all cases. The first two patients reported 70% improvement after one month, 60% improvement after 6 months, and 30-50% after one year, versus baseline. The third patient reported complete pain resolution lasting approximately 5 months, after which the pain reappeared with the same intensity as before. CONCLUSIONS: Radiofrequency is a satisfactory treatment option, affording adequate analgesia, though the effects are sometimes temporary.