Bilateral Sphenopalatine Ganglion Block With or Without Bilateral Greater Occipital Nerve Block for Treatment of Obstetric Post-Dural Puncture Headache

Overview

Post-dural puncture headache is a common complication, following neuraxial techniques. The obstetric population is particularly prone to PDPH. Therefore, treatment of PDPH is a key issue in obstetric anesthesia. Conservative treatment for PDPH includes adequate hydration, systemic analgesia with paracetamol and non-steroidal anti-inflammatory drugs and increased caffeine intake, as well as bed rest. If these measures are unsuccessful, the gold standard for the treatment of PDPH is the epidural blood patch which is an invasive technique. The use of nerve blocks for treating headache symptoms are well known techniques that have been previously used for managing some specific types of chronic headache such as cervicogenic headache, cluster headache, migraine, and occipital neuralgia and there are some recently published studies reporting that these blocks may be beneficial in treating PDPH and the available evidence although showing improvements in the visual analogue (VAS) scores and a reduced number of patients requiring an epidural blood patch, but it is still poor. Less invasive techniques such as SPG block and GONB are attractive therapeutic options which may eliminate the need for EBP in obstetric patients suffering from PDPH. Up to the best of our knowledge this is the first randomized trial to investigate the analgesic efficacy of adding SPG block either alone or in combination with GONB to PDPH treatment.

Post-dural puncture headache (PDPH) is a relatively common complication following dural puncture which is more frequently noted in parturients undergoing cesarean section (CS) under neuraxial anesthesia. The mechanism of nociception in PDPH is still indistinct. However, it is thought to be related to the decrease in intracranial pressure caused by the cerebrospinal fluid (CSF) leak through the dural defect leading to a downward pull of intracranial nociceptive structures which is further exacerbated by compensatory cerebral vasodilation. Managing Post-dural Puncture Headache is a challenge for most anesthesiologists as the gold standard and definitive treatment; epidural blood patch (EBP) itself can lead to inadvertent dural puncture that caused the complication in the first place. Medical and conservative management of PDPH may not provide symptomatic relief and anesthesiologists are on a constant lookout for techniques that can provide immediate and sustained relief from this debilitating complication. The use of regional techniques and nerve blocks for the treatment of headache symptoms are well known techniques. The transnasal sphenopalatine ganglion (SPG) block which is an easy block that requires minimal training was shown to be helpful in the PDPH treatment with promising results. The SPG surrounded by mucous membrane within the posterior nasal turbinate, is a parasympathetic ganglion of cranial nerve (CN) VII which mediates intracranial vasodilation. The role of this block in PDPH management may be due to the vasoconstriction resulting from the parasympathetic block. Additionally, its relationship to the fifth cranial nerve (trigeminal nerve) may simultaneously relieve the frontal headache. Another regional technique that can be used is the Greater Occipital Nerve Block (GONB) that has been previously used for managing some specific types of chronic headache such as cervicogenic headache, cluster headache, migraine, and occipital neuralgia and there are some recently published studies reporting that GONB may have a beneficial role in PDPH management. In addition, it is a superficial block which can be done at the patient's bedside under ultrasound guidance. The greater occipital nerve is the main sensory nerve of the occipital region that arises from the dorsal ramus of cervical spinal nerve II. The neuromodulation effect together with decreased central sensitivity resulting from meningial and paraspinal muscles irritation as well as blocking the spinal cord dorsal horn afferent fibers may explain the role of GONB in relieving PDPH symptoms. Moreover, the sensitive neurons of the upper cervical cord are close to the trigeminal caudal nucleus. Therefore, its afferences may also be blocked with this technique. The available evidence of these blocks for treating PDPH although showing improvements in the visual analogue (VAS) scores and a reduced number of patients requiring an epidural blood patch, but it is still poor. Moreover, there are some clinical scenarios in which the patient may refuse treatment with the epidural blood patch, or there may be a contraindication for its use. Hence, we hypothesized those obstetric patients who are particularly prone to PDPH may get benefit from these less invasive techniques and that these blocks may be added to the treatment of patients suffering from PDPH in order to avoid the invasive EBP.