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Abstract
The sphenopalatine ganglion (SPG) block is a simple and valuable technique that was discovered over a century ago, but, unfortunately, very few anesthesiology providers are familiar with this block. After some of our recent publications, physicians from different countries have reached out to us requesting more specifics on how we perform our version of the block. In this report, we provide a brief history of the block and demonstrate our three effective, simple, readily available, and inexpensive methodologies with images. We are proud to share that our three SPG block techniques have so far effectively relieved patients of chronic migraines, acute migraines, tension headaches, moderate-to-severe back pain, and post-dural puncture headaches.
- obstetrics
- acute pain
- post-dural puncture headache
- back pain
- anesthesia, local
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Introduction
The sphenopalatine ganglion (SPG) block is a simple and valuable technique that was discovered over a century ago,1 but, unfortunately, to this day, very few anesthesiology providers are familiar with this block. Since the publication of our experiences with this block in Regional Anesthesia and Pain Medicine,2 3 physicians from different countries have reached out to us requesting more specifics on how we perform our version of the block. After we shared additional images and details with those who requested, many physicians wrote back to us with excitement that they have tried the block for the first time on their patients, and the block effectively relieved their patients’ pain as well! To help even more anesthesiologists safely perform this block, we would like to provide a brief history of the block and further demonstrate our three effective and simple methodologies with images.
The SPG is known to be the largest collection of parasympathetic neurons located bilaterally, just outside the brain.4 The axons of this ganglion supply nerve signals to the nasal mucosa and lacrimal gland and affect local blood flow.4 5 When the SPG is activated, cerebral vasodilation occurs via the release of acetylcholine, nitric oxide, and vasoactive intestinal peptide. Increased flow of these chemicals may increase plasma protein extravasation and cause neurogenic inflammation. This is thought to cause the activation of the trigeminal nociceptors and contribute to the sensation of headache.6 Since the SPG is covered by only 1–2 mm of connective tissue, it is accessible for topical administration of medication.5
Back in 1908,1 Dr Sluder was the first physician to block the SPG via a transnasal approach. He administered a 20% cocaine solution into the SPG region. Then, in the 1970s, Dr Ruskin studied the SPG block and reported that it could be effective in the treatment of not only headaches but also facial neuralgias, temporomandibular joint dysfunction, low back pain, and hiccups.7 In 1985, Dr Kittrelle demonstrated that a 4% lidocaine solution had an equivalent potency to the utilization of cocaine in the performance of this block.8 Today, companies, such as Allevio, SphenoCath, and Tx360, have created intranasal devices for the administration of the SPG block through the transnasal approach.4 However, these devices can be expensive and are not readily available at all institutions.
Other approaches of anesthetizing the SPG outside the transnasal approach have also been explored. For instance, some medical providers use the transoral approach, where a curved dental needle is inserted through the posterior palatine canal into the sphenopalatine foramen.9 The lateral approach is occasionally used as well, where a straight needle is inserted into the pterygopalatine fossa through the infratemporal fossa. The lateral technique entails locating the ganglion through the cheek with the help of ultrasound,10 X-ray technology, fluoroscopy, and/or CT.11 All of these SPG block applications have been reported to be effective, but they often require a significant amount of setup, are expensive, and may need multiple personnel to administer. Furthermore, these techniques may expose patients and healthcare providers to additional radiation.
The original transnasal SPG block approach continues to be the simplest and most tolerable approach for patients.9 Since 1994, Dr Shaul Cohen has been effectively performing the SPG block via the transnasal approach with supplies that are readily available in every medical facility. Through the years, he has taught many medical students and anesthesiology residents how to perform this block, and, together, we have perfected three simple SPG block administration methodologies.
Methods
We have so far applied our three treatment methods to patients experiencing various head, neck, and back pain etiologies. For all of our treatment methods, the patients are positioned in the Trendelenburg position with cervical spine extension (‘chin-up’). If a patient becomes light-headed, gets neck pain during the procedure, or had a history of neck surgery, then the patient is kept in the Trendelenburg position with neutral head position (no cervical spine extension).
The first treatment methodology is considered the most comfortable for the patient. Lidocaine 4% solution is drawn up into a 5 mL syringe and slowly dripped, drip by drip, from the syringe into each nostril until the patient feels the medication in the back of his/her throat. This typically requires the administration of somewhere between 0.5 and 1.5 mL of the medication. The patient is kept in the position described above for 15 min. Then, the patient is asked if the headache feeling has improved. If the original headache etiology was secondary to a post-dural puncture headache, then the patient is asked to briefly sit up. If the headache is not sufficiently relieved, then this procedure is repeated in a row, up to two more times. The total length of this procedure lasts between 16 and 48 min.
More than 70% of the patients respond to the first treatment methodology. If a patient does not respond to the first treatment methodology, we assume that the local anesthetic drops did not reach the SPG. We then perform our second treatment methodology, which is a more direct approach. In this approach, we create our SPG block applicator from the readily available supplies in every medical facility. Figure 1 depicts the components of our SPG block applicator: (1) a hollow cotton swab, (2) intravenous extension tubing with a stopcock, (3) 5 mL syringe, (4) any medical tape (optional), (5) lidocaine 2% water-soluble ointment, and (6) lidocaine 4% solution. We begin by cutting the intravenous extension tubing and making it 10 inches long. We then open a new hollow cotton swab and dip it into lidocaine 2% water-soluble ointment. This hollow cotton swab is then attached to the 10-inch intravenous extension tubing that has the stopcock. If needed, any medical tape can be used to secure the hollow cotton swab to the intravenous extension tubing. A 5 mL syringe is connected to the intravenous extension tubing. The cotton swab part of this device is gently inserted perpendicularly into the patient’s nostril until it is in contact and bounces against the posterior wall of the pharynx. Lidocaine 4% solution is then administered via the syringe until the patient feels the mediation in the back of his/her throat. This requires somewhere between 0.5 and 1.5 mL of the solution. Figure 2 depicts how the SPG block applicator looks when it is assembled.
The components of the sphenopalatine ganglion block applicator: a hollow cotton swab dipped into 4% lidocaine water-soluble ointment; 10-inch intravenous extension tubing with a stopcock; and the intravenous extension tubing attached to a 5 mL syringe.
Assembled version of the sphenopalatine ganglion block applicator.
A second hollow cotton swab device is created the same way and the medication is administered in a similar manner into the second nostril. The syringes are disconnected temporarily, and the applicators remain in the patient’s nostrils for 15 min while the patient remains in the described position. Similar to the first treatment methodology, after 15 min, the patient is asked how his/her head feels. If the patient originally had a post-dural puncture headache, then he/she is asked to briefly sit up. If the headache is not sufficiently relieved, then this procedure is repeated in a row, up to two more times. If the procedure is being repeated, the syringes should be temporarily reattached each time for the administration of the medication.
There have also been several occasions when hollow cotton swabs were not available at our hospital, and from that we established our third treatment methodology. When hollow cotton swabs are not available, the 6-inch, solid, medical wooden, all-purpose cotton-tipped applicators can be used. New cotton-tipped applicators are opened and dipped into lidocaine 2% water-soluble ointment. One cotton-tipped applicator is gently inserted perpendicularly into the patient’s nostril until it is in contact and bounces against the posterior wall of the pharynx. A second cotton-tipped applicator is inserted in the same manner into the second nostril. When the anesthesiology provider gently taps with a finger on one of the cotton-tipped applicators, the untouched cotton-tipped applicator in the other nostril bounces as well. Then, lidocaine 4% solution is drawn up into a 5 mL syringe and slowly dripped, drip by drip, from the syringe into each nostril until the patient feels the medication in the back of his/her throat. The way that the lidocaine 4% solution is dripped in this method is the same way that it is dripped in our first treatment methodology; however, this time, the cotton-tipped applicators help the medication reach the SPG. Like in the other two treatment methodologies, once the patient feels the medication in the back of the throat, the patient remains in the described position for 15 min. After 15 min, the patient is asked how his/her head feels. If the patient is being treated for a post-dural puncture headache, then he/she is asked to briefly sit up. If the headache is not sufficiently relieved, then this procedure is repeated in a row, up to two more times. If the procedure is being repeated, the cotton-tipped applicators remain in the patient’s nostril throughout the entire procedure.
Prior to discharge from the hospital, all patients are taught how to perform our first treatment methodology, and they are prescribed lidocaine 2% solution. Typically, the headache disappears completely at the hospital, but sometimes it returns at home. If the headache does return, the patients are instructed to perform the first technique themselves. This significantly reduces the chance that they will need to come back to the hospital for another treatment.
Results
As mentioned previously, the current speculation is that the SPG block is effective because the nociceptors in the SPG get blocked though our techniques. However, we truly do not know how a local anesthetic, which should, in theory, only have a temporary effect, often completely eradicates both acute and chronic headaches. For instance, we had a 32-year-old patient who was at 36 weeks gestation with a medical history significant for a surgically corrected type 1 Arnold Chiari malformation, who presented with a chronic, intractable headache. Neurologists treated this woman with intravenous methylprednisolone, ketorolac, and morphine, but she had no relief. We then performed our SPG block treatment, and she was discharged home the same day, without relapse of headaches during the 6 months of follow-up by our pain service.12
We have also had many other patients whose chronic migraines, tension headaches, and other types of primary headaches resolved after our SPG block. Similarly, post-dural puncture headaches, which can typically be symptomatic for up to a week if not treated, often resolve after the application of the SPG block.2 3 13 Even after the temporary effects of lidocaine wear off, the headache, typically, does not come back. This is an incredible phenomenon that would benefit from further investigation.
Discussion
A recent randomized controlled trial, conducted by Jespersen and colleagues, confirmed that SPG block is effective in relieving post-dural puncture headache and decreases the need of epidural blood patch, and, interestingly, the results of the study suggested that local anesthetic might not be the culprit behind why SPG block works.13 In this study, pain relief from the SPG block when performed with local anesthetic (lidocaine 4% in combination with ropivacaine 0.5%) was comparable with that of when the SPG block was performed with just saline.13 This suggests that the SPG block may work via a placebo effect, or the SPG might be blocked not by the local administration of anesthetic but just by the mechanical manipulation of the ganglion. We suspect that the mechanical pressures with a saline-dipped cotton-tipped applicator may have a similar effect on our SPG block.
We also know of anesthesiology providers who have effectively performed the block with lidocaine solutions with concentrations 1%–4% or bupivacaine 0.5%. We are not aware of any study that has determined which solution has a better success rate.
Conclusions
More research is certainly necessary to further explain the intricacies of how and why the SPG block works the way it does. We hope that in the future, physicians attempt to replicate the SPG block with saline administration, as well as perform the block with various types and concentrations of local anesthetics to determine whether the effectiveness of the SPG block could be further enhanced. In the meantime, for those who will be exploring the SPG block in research studies and/or for those who will be trying the block for the first time on their patients, we hope that our three simple SPG block administration methodologies are useful and beneficial for future patients. We are proud to share that our three SPG block methodologies that we described here have so far effectively relieved patients of chronic migraines, acute migraines, tension headaches, moderate-to-severe back pain, and post-dural puncture headaches.2 3 14–16 Our three SPG block techniques are simple to set up, readily available, inexpensive, effective, and safe. Readers, please do not hesitate to contact us with any additional comments or questions.
Acknowledgments
First of all, we would like to thank all the patients and their families who volunteered to have the sphenopalatine ganglion block administered to them. We also express our sincere gratitude to all the physicians who have read our previous publications with interest and have reached out to us requesting more details on how we perform our sphenopalatine ganglion blocks.
Footnotes
Twitter @daniellelevinmd
Contributors DL and SC contributed to the concept, design, data collection/processing, analysis/interpretation, literature search, writing manuscript, and critical review.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Patient consent for publication Not required.
Provenance and peer review Not commissioned; externally peer reviewed.