Sphenopalatine Ganglion (SPG) Block

The sphenopalatine ganglion (SPG) block is not a new intervention, but it has experienced renewed interest within the anesthesia and pain management communities. First described by Dr. Greenfield Sluder in 1908, the SPG block has demonstrated utility for more than a century in the treatment of various facial pain syndromes, complex regional pain syndromes (CRPS), trauma-related facial pain, and more recently, post-dural puncture headache (PDPH). Although high-level evidence supporting its use for PDPH remains limited, early case reports and small cohort studies are promising. Compared to the more invasive and resource-intensive epidural blood patch (EBP), the SPG block offers a simple, cost-effective, and low-risk alternative.

Anatomy

The sphenopalatine ganglion is a small, triangular parasympathetic ganglion approximately 5 mm in diameter, located superficially in the pterygopalatine fossa—posterior to the middle nasal turbinate and anterior to the pterygoid canal. Also referred to as the nasal ganglion, pterygopalatine ganglion, or Meckel's ganglion, it lies just beneath a 1–2 mm layer of connective tissue and mucosa. This superficial positioning allows for non-invasive access using transnasal techniques without mucosal penetration.

The SPG serves as a convergence point for parasympathetic, sympathetic, and sensory fibers. It receives:

  • Preganglionic parasympathetic input via the greater petrosal nerve

  • Sympathetic fibers from the deep petrosal nerve

  • Somatic sensory afferents from the maxillary division of the trigeminal nerve

Innervation areas include the upper pharynx, nasal cavity, palate, paranasal sinuses, and lacrimal glands. Owing to this complex innervation pattern and superficial location, the SPG is a favorable target for local anesthetic application in various pain conditions.

Current Literature

There is a robust body of literature on SPG blockade for head and facial pain syndromes; however, evidence supporting its efficacy in PDPH is more limited and primarily based on case reports and small observational studies.

  • The first reference to SPG blockade for PDPH appeared in 2001 by Cohen et al.

  • In 2009, Cohen and colleagues published a series involving 13 obstetric patients with PDPH following inadvertent dural puncture. Of these, 11 experienced satisfactory pain relief with SPG blockade alone, avoiding the need for EBP. Two patients ultimately required an EBP.

  • Patel et al. conducted a retrospective study involving 72 patients, comparing SPG block to EBP. Pain scores at 1 and 24 hours post-procedure showed no significant difference between the groups. Notably, the EBP group experienced a higher incidence of complications.

  • In 2015, Kent and Mehaffey reported a series of three emergency department patients with PDPH who responded favorably to SPG block using 2% viscous lidocaine.

  • A follow-up study by the same authors was published in the Journal of Clinical Anesthesia, further supporting the block’s effectiveness in parturients.

  • A 2017 review by Nair and Rayani, published in the Korean Journal of Pain, examined SPG block techniques and their relevance in managing PDPH, reinforcing the growing interest in this approach.

Figure showing proper placement of hollow swabs, suitable for eased placement into posterior nasopharynx

SPG Block Placement Technique

The sphenopalatine ganglion (SPG) block is one of the simplest and least invasive techniques available to pain management providers. After thorough explanation and obtaining informed consent, the patient is positioned supine with the head gently extended to create an optimal gravitational pocket that facilitates local anesthetic pooling and absorption over the SPG. This position should be maintained comfortably for 10–30 minutes to ensure adequate exposure.

Caution should be exercised in patients with a history of epistaxis, nasal polyps, or other intranasal pathologies, as these may increase the risk of complications.

A soft, padded applicator—ideally with a hollow shaft—is selected for medication delivery. Culture swabs are often used for this purpose due to their compatibility, availability, and absorbent properties. The applicator tip is saturated with a high-concentration, fast-acting local anesthetic, typically 2–4% lidocaine. Viscous lidocaine may also be used as an alternative.

Each swab is inserted into the nostril, swab-end first, and advanced along the nasal floor until resistance is encountered—indicating placement near the posterior nasopharyngeal wall, adjacent to the SPG. The applicators are left in place for 10–30 minutes. If desired, 1–3 mL of additional local anesthetic may be administered via the hollow shaft to enhance efficacy. This method is cleaner and more efficient than dripping or wicking medication along a solid applicator.

Patients often report relief of symptoms within 5–10 minutes. After the dwell time, the applicators are removed and pain is reassessed. Although no major complications have been reported, transient lightheadedness and minor epistaxis are occasionally noted in the literature.

Clinical Pearls

  • Consider a mild Trendelenburg position to enhance gravitational pooling of anesthetic.

  • Pretreatment of the nares with a topical vasoconstrictor such as oxymetazoline (Afrin) may reduce bleeding and improve tolerability.

Conclusion

The SPG block is a promising intervention for patients suffering from various pain syndromes, with growing relevance in the management of post-dural puncture headache (PDPH). Its non-invasive nature, minimal resource requirement, and favorable safety profile make it an appealing alternative to more invasive procedures such as the epidural blood patch (EBP).

Unlike EBP, which carries risks of further dural puncture, nerve injury, and infection, the SPG block offers a safer option for patients unwilling or unsuitable for repeat neuraxial procedures. As such, the technique has increasing utility for anesthesia, emergency medicine, and neurology providers. The resurgence of interest in this time-tested intervention highlights a long-overdue expansion of options for managing PDPH and other craniofacial pain syndromes.

SOURCES

  • Pain Physician 2013; 16:E769-E778 • ISSN 2150-1149

  • A Novel Revision to the Classical Transnasal Topical Sphenopalatine Ganglion Block for the Treatment of Headache and Facial Pain

  • Kenneth D. Candido, MD1,2, Scott T. Massey, MD1, Ruben Sauer, MD1, Raheleh Rahimi Darabad, MD1, and Nebojsa Nick Knezevic, MD, PhD1,2

  • 5. Cohen S, Sakr A, Katyal S, Chopra D. Sphenopalatine ganglion block for postdural puncture headache. Anaesthesia. 2009;64:574–575. [PubMed]

  • 6. Patel P, Zhao R, Cohen S, Mellender S, Shah S, Grubb W. Sphenopalatine ganglion block (SPGB) versus epidural blood patch (EBP) for accidental postdural puncture headache (PDPH) in obstetric patients: a retrospective observation; 32nd Annual Meeting of the American Academy of Pain Medicine; 2016 Feb 18-21;

  • 7. Kent S, Mehaffey G. Transnasal sphenopalatine ganglion block for the treatment of postdural puncture headache in the ED. Am J Emerg Med. 2015;33:1714.e1–1714.e2. [PubMed]

  • 8. Kent S, Mehaffey G. Transnasal sphenopalatine ganglion block for the treatment of postdural puncture headache in obstetric patients. J Clin Anesth. 2016;34:194–196. [PubMed]

  • 9. Nair A, Kumar Rayani B. Sphenopalatine ganglion block for relieving postdural puncture headache: technique and mechanism of action of block with a narrative review of efficacy

  • Korean J Pain. 2017 Apr; 30(2): 93–97. Published online 2017 Mar 31. doi: 10.3344/kjp.2017.30.2.93