Comparisons between ipsilateral side and contralateral side were analyzed, but no temperature changes were showed except one area (between before and 30 minutes after TN-SPGB in left V1).
The comparison between pain relief group and pain maintenance group was analyzed in 15 TN-SPGBs (Table 4). There was no one in pain aggravation group. Herpes zoster in the nonface area, headaches, and anosmia are excluded. Pain mostly decreased after TN-SPGB in patients with head and neck pain, including those with herpes zoster, and the comparison between pain relief group and pain maintenance group was not statistically significant (P = .3636).
Millions of people around the world suffer headaches and facial pain which have been progressed chronically. Medications are the primary treatment for many types of headache. Although invasive therapy for head and neck lesions is effective, it is not applied in most cases because of the high risk of complications in some cases. TN-SPGB is known to be safe and effective and has thus been applied in clinical practice since 2000. TN-SPGB has been reported to be effective in treating cluster headache, nicotine addiction, and postdural puncture headache. Indications for TN-SPGB are gradually expanding.
Regarding studies on TN-SPGB, the first randomized controlled trial was conducted by Scudds et al with 61 myofascial pain syndrome and fibromyalgia patients in 1995. Krasuski et al reported on patients with severe headache caused by head trauma, dental work, fibromyalgia, and pharyngitis, who were treated with SPGB with sterile cotton sticks soaked in 4% lidocaine. Pain relief was reported for 12 of 15 patients.
Because of the effectiveness and low risk of complications of TN-SPGB, relevant instruments have been developed. However, a method was lacking for validating the success of TN-SPGB, with pain relief being the only measure of its effectiveness; in cases where TN-SPGB has no effect, it is unclear whether the block failed or was ineffective. In sympathetic block, thermography after SGB was first reported to confirm its success in the 1980s; temperature increases after the procedure are used to determine the effectiveness of the block.
In this study, we attempted to determine the success of TN-SPGB by measuring facial temperature changes before and 30 minutes after TN-SPGB, using DITI. After TN-SPGB, the temperatures decreased significantly on both sides of V1 area.
Numerous hypotheses can be drawn from interpretations of the aforementioned results. First, the SPG can be hypothesized to have sympathetic, parasympathetic, and sensory nerve components, but not all 3 nerves would be blocked in TN-SPGB because transnasal approach of the SPG is blocked by diffusion. Second, even if all 3 nerves are blocked, the parasympathetic nerve blocks would become dominant in the SPG when the transnasal approach is used. TN-SPGB has been found to be effective in treating migraines, and migraine medications are known vasoconstrictors, which supports the aforementioned hypotheses. Hence, TN-SPGB might theoretically exert a vasoconstrictive effect of parasympathetic blocks as a compensatory effect of sympathetic nerve blocks. However, no studies have been conducted on the cranial autonomic system and temperature changes in the head and neck. Therefore, additional controlled studies are needed.
We also noted that the temperature changes at V2 and V3 areas are not clear. The reasons for this phenomenon could be that whereas the blood supply is sufficient in the front of the brain at V1, it is insufficient at V2 and V3 because of structures such as nasal cavities, oral cavities, and sinuses.
At V2 area, the temperature tended to increase slightly, which may have been due to sympathetic dual innervation of the SPG. The decrease in temperature at V1 area may have been related to compensatory activity of the sympathetic nerves.
Although the lesion location was identified as being on the left or right side and SPGB was performed in only one nostril accordingly, the temperature decreased on both sides of V1 area regardless of the direction of the block. This result suggests that only one-sided TN-SPGB is necessary, even in patients with bilateral symptoms. This result could be related to the structural properties of the mucous membrane and the lack of bony structures in the SPG.
Regardless of the pain site, pain relief and temperature changes at V1 area have shown a significant correlation, suggesting that they can be a good indicator for verifying the effects of TN-SPGB.
Wasserman et al reported temperature increases of approximately 1.4°C in both zygomatic areas after TN-SPGB, contrary to our results. They reported that the SPG received an additional sympathetic innervation of the maxillary artery plexus and increased in temperature after TN-SPGB because of sympathetic nerve blockade. In addition, the methods differed between the aforementioned study and the present study, such as drug volume and concentration as well as the instruments used.
We concluded that TN-SPGB reduced facial temperature in the V1 area, and was effective on both sides. The limitations of this study are as follows. First, this was a retrospective study. Second, the number of patients was relatively small. Third, the participants were patients rather than healthy individuals. Fourth, we did not employ a control group. Fifth, we did not use standardized instruments for TN-SPGB because such devices (e.g., Sphenocath; Dolor Technologies, Scottsdale, AZ) are unavailable in South Korea.
Conceptualization: Na Eun Kim, Sook Young Lee, Ji Eun Kim, Jong Bum Choi.
Data curation: Na Eun Kim, Bumhee Park, Yeo Rae Moon, Sunok Kim, Seryeon Lee, Hyuk Soo Chang, Hae Won Jeong, Hyungbae Park, A Ram Lee, Soohwan Ahn, Tae Kwang Kim, Jong Bum Choi.
Formal analysis: Na Eun Kim, Bumhee Park, Yeo Rae Moon, Ho Young Gil, Ji Eun Kim, Jong Bum Choi.
Investigation: Na Eun Kim, Ho Young Gil, Sunok Kim, Seryeon Lee, Hyuk Soo Chang, Hae Won Jeong, Hyungbae Park, A Ram Lee, Soohwan Ahn, Tae Kwang Kim, Ji Eun Kim, Jong Bum Choi.
Methodology: Na Eun Kim, Bumhee Park, Yeo Rae Moon, Sook Young Lee, Ho Young Gil, Ji Eun Kim, Jong Bum Choi.
Project administration: Na Eun Kim.
Resources: Sunok Kim, Seryeon Lee, Hyuk Soo Chang, Hae Won Jeong, Hyungbae Park, A Ram Lee, Soohwan Ahn, Tae Kwang Kim.
Supervision: Sook Young Lee, Ho Young Gil, Ji Eun Kim, Jong Bum Choi.
Writing – Original Draft: Na Eun Kim.
Writing – Review and Editing: Ji Eun Kim, Jong Bum Choi.
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Keywords:Copyright © 2019 The Authors. Published by Wolters Kluwer Health, Inc. All rights reserved.
face; pain management; sphenopalatine ganglion block; temperature