RCT of SPG Blocks for Post-dural Headache

The postdural puncture headache (PDPH) is a well-documented complication of dural puncture.
Depending on a number of factors, the overall incidence of PDPH following unintended dural
puncture with an epidural placement needle is typically around 50%, but can be as high as 70%
for certain populations.(1, 2, 3)

The headache is characterized by being frontal or occipital in nature, with a typical onset
of 6-72 hours after dural puncture. It is normally exacerbated by the upright position and
improved by the supine position. Associated symptoms may include photophobia, nausea,
vomiting, dizziness, tinnitus, neck stiffness, decreased hearing and visual changes. (2)
These symptoms tend to be extremely debilitating in affected patients, severely limiting
their functional capacity until the resolution of the headache.(2) The compromise is even
greater when considering these women also need to care for a newborn, as the time after birth
is important for forming attachment and encompasses many new obligations for the new mother.

The treatment of the PDPH often begins with conservative treatment including supportive
therapies such as hydration, bed rest, acetaminophen, NSAIDs, and oral opioids. In addition,
some evidence exists for the use of caffeine (1,2). While these do not hasten recovery, they
may improve symptoms. For PDPH of all etiologies, 72% will resolve spontaneously in 7 days
and 89% by 14 days. (1)

For patients with moderate to severe symptoms or long lasting headaches, the gold standard
for treatment of headaches that do not resolve is the epidural blood patch (EBP) (1,2,4).
This treatment has been shown to be effective in 70-98% of patients (1,2,4). However, it has
numerous contraindications including: fever, infection, coagulopathy, active neurological
disease, patient refusal. In addition, a potential complication is yet another dural
puncture. Also, while the EBP is generally very safe, it is an invasive procedure with its
own complications; it has been associated with very rare but serious complications including:
moderate long-lasting backache, meningitis, epidural abscess formation, epidural hematoma
formation, and neurologic deficit development. (5-8)

The sphenopalatine ganglion (SPG) is a parasympathetic ganglion with fibers that innervate
the cerebral and meningeal blood vessels cause vasodilation and activation of nociceptive
fibers in the meninges, which is perceived as referred pain from the head by the sensory
cortex. (9) So blockade of these fibers can theoretically relieve headache symptoms from
other causes. The SPG block has been safely used for many years to treat chronic facial or
head pain from cluster headaches, trigeminal neuralgia, postherpetic neuralgia, atypical
facial pain from cancer, and CRPS I and II. (9)

The SPG block is safe and easy to perform. The only contraindications include patient
refusal, a true allergy to local anesthetic, and Hereditary Hemorrhagic Telangiectasia (HHT).
(9,10) Documented potential complications include transient nausea and epistasis. (9,10) The
SPG is located in the pterygopalatine fossa, which is just posterior to the middle turbinate,
and anterior to the pterygoid canal. It is about 5 mm in size and there is a 1 to 1.5
mm-thick layer of connective tissue and mucous membrane surrounding the ganglion, so drug
enters easily by a topical application. (9-11) There are multiple approaches to the blockade
of this ganglion, but the easiest and least invasive is the transnasal approach involving
entering the nare with the application of lidocaine jelly on a cotton swab directed
posteriorly in the nasal passage to the SPG. (9) The cotton swab should remain in place for
10 minutes. (9,10)

Recently, the SPG block has also been shown to be effective in relieving the symptoms of the
PDPH in case series and case reports. One case series performed SPG blocks in 3 parturients
with confirmed PDPH in the emergency room using 2% viscous lidocaine. All 3 patients had good
relief after the intervention and did not require EPB. The authors suggested that the
procedure can be safely and accurately performed in the emergency room, which will reduce
visit time, provide good pain relief, and the EBP can be deferred. (10) Another case series
of 32 patients with confirmed PDPH of multiple etiologies showed that the SPG block prevented
the need for EBP in 69% of the cases. (12)

In addition, a recent randomized placebo controlled trial of SPG block vs. saline for acute
headache in the ER showed that for patients with acute anterior headache, SPG block with
bupivacaine resulted in a reduction of HA symptoms. However, reduction of headache symptoms
was also seen in the SPG block with saline group, indicating a possible placebo effect of the
performance of the block. (13)

The purpose of the study is to assess the effectiveness of the SPG block with lidocaine vs.
SPG block with placebo on preventing the need for EBP in women who develop PDPH after
accidental dural puncture during placement of LEA for labor.

Inclusion Criteria:

- Females

- age 18-50

- Post Dural Puncture Headache after documented accidental dural puncture during
placement of LEA for labor and no better explanation for headache

- onset of HA within 72 hours of delivery.

Exclusion Criteria:

- true allergy to local anesthesia

- Hereditary Hemorrhagic Telangiectasia

- inability to understand pain scores and other questionnaires

- inability to speak English

- contraindication to acetaminophen or NSAIDs

- temperature >38.5 C

- prior Epidural Blood Patch done for this headache