Sphenopalatine ganglion: block, radiofrequency ablation and neurostimulation - a systematic review

Comparison of Greater Occipital Nerve Blockade and Sphenopalatine Ganglion Blockade in Patients with Episodic Migraine

Objectives: Compare the effects of greater occipital nerve (GON) and sphenopalatine ganglion (SPG) blocks on headache intensity and duration, number of headache days, and disability in patients with episodic migraine. Methods: In this prospective single-blind randomized study, patients with episodic migraine were randomly divided into two groups: GON and SPG block groups. Patients received blocks once a week for 4 weeks, and once a month for 2 months. The number of headache days, the headache duration, numeric rating scale (NRS) scores, and number of acute medical treatments were assessed before the procedures and 1 month, 2 months, and 3 months after the procedures. Disability was evaluated using the migraine disability assessment (MIDAS) questionnaire at baseline and 3 months after treatment. This study protocol is registered at ClinicalTrials.gov (NCT06243874.). Results: 19 patients in the GON block group and 18 patients in the SPG block group were evaluated. Significant improvements in pain severity, headache duration, number of headache days, and the need for acute medical treatment were observed in the 1st, 2nd, and 3rd months compared to baseline in the two groups (p < 0.001). There were significant improvements in the MIDAS scores in the third month (p < 0.001). The GON block group showed a greater reduction in headache intensity, duration, number of headache days, and MIDAS scores compared to the SPG block group in the 3rd month (p < 0.001). Conclusions: GON block reduces headache duration, intensity, the number of headache days, and the need for acute medical treatment much more than SPG block in patients with episodic migraine.

Review of craniofacial pain syndromes involving the greater occipital nerve: relevant anatomy, clinical findings, and interventional management

Craniofacial pain syndromes exhibit a high prevalence in the general population, with a subset of patients developing chronic pain that significantly impacts their quality of life and results in substantial disabilities. Anatomical and functional assessments of the greater occipital nerve (GON) have unveiled its implication in numerous craniofacial pain syndromes, notably through the trigeminal-cervical convergence complex. The pathophysiological involvement of the greater occipital nerve in craniofacial pain syndromes, coupled with its accessibility, designates it as the primary target for various interventional procedures in managing craniofacial pain syndromes. This educational review aims to describe multiple craniofacial pain syndromes, elucidate the role of GON in their pathophysiology, detail the relevant anatomy of the greater occipital nerve (including specific intervention sites), highlight the role of imaging in diagnosing craniofacial pain syndromes, and discuss various interventional procedures such as nerve infiltration, ablation, neuromodulation techniques, and surgeries. Imaging is essential in managing these patients, whether for diagnostic or therapeutic purposes. The utilization of image guidance has demonstrated an enhancement in reproducibility, as well as technical and clinical outcomes of interventional procedures. Studies have shown that interventional management of craniofacial pain is effective in treating occipital neuralgia, cervicogenic headaches, cluster headaches, trigeminal neuralgia, and chronic migraines, with a reported efficacy of 60-90% over a duration of 1-9 months. Repeated infiltrations, neuromodulation, or ablation may prove effective in selected cases. Therefore, reassessment of treatment response and efficacy during follow-up is imperative to guide further management and explore alternative treatment options. Optimal utilization of imaging, interventional techniques, and a multidisciplinary team, including radiologists, will ensure maximum benefit for these patients.

Is transoral sphenopalatine ganglion blockade more effective on postoperative pain than endoscopic sphenopalatine ganglion blockade?

PURPOSE

In this study, we aimed to examine and compare the effects of endoscopic SPGB and transoral SPGB on postoperative pain control and patient satisfaction in patients undergoing septoplasty.

METHODS

Participants were randomly divided into three groups, no blockade (n:20), endoscopic SPGB (n:20), and transoral SPGB (n:20). Those who had no blockage were included in the control group. Demographic data of patients, such as age and sex, VAS (visual analogue scale) and postoperative pain scores (PPS) [determined at arrival in the post-anesthesia care unit (PACU) and after 2, 6, 12, and 24 h], general analgesic use (24 and 168 h after surgery) and postoperative Quality of Recovery (QoR-15) values were recorded and compare them.

RESULTS

The PPS PACU of 2 h, 6 h, 12 h, and 24-h values of the transoral group were lower than the endoscopic and control groups (p < 0.001).The values of 24 h and 168 h of analgesic use in the transoral group were lower than in the control and endoscopic groups (p < 0.001).The average recovery QoR-15 scores at 12 h and 24 h differed according to the groups (p < 0.001) and the highest values were in the transoral group (p < 0.001).

CONCLUSION

Transoral SPGB is more effective in postoperative pain control than endoscopic SPGB, it decreases the use of postoperative analgesics and improves postoperative recovery scores.

Neuromodulation for Craniofacial Pain and Headaches

Headaches and facial pain are highly prevalent diseases but are often difficult to treat. Though there have been significant advances in medical management, many continue to suffer from refractory pain. Neuromodulation has been gaining interest for its therapeutic purposes in many chronic pain conditions, including headaches and facial pain. There are many potential targets of neuromodulation for headache and facial pain, and some have more robust evidence in favor of their use than others. Despite the need for more high-quality research, the available evidence for the use of neuromodulation in treating headaches and facial pain is promising. Considering the suffering that afflicts patients with intractable headache, neuromodulation may be an appropriate tool to improve not only pain but also disability and quality of life.

Trans-nasal sphenopalatine ganglion block for post-dural puncture headache management: a meta-analysis of randomized trials

OBJECTIVE

To evaluate the efficacy and safety of trans-nasal Sphenopalatine Ganglion (SPG) block over other treatments for Post-Dural Puncture Headache (PDPH) management.

METHODS

A systematic literature search was conducted on databases for Randomized Controlled Trials (RCTs) comparing trans-nasal SPG blockade for the management of PDPH over other treatment modalities. All outcomes were pooled using the Mantel-Haenszel method and random effect model. Analyses of all outcomes were performed as a subgroup based on the type of control interventions (conservative, intranasal lignocaine puffs, sham, and Greater Occipital Nerve [GON] block). The quality of evidence was assessed using the GRADE approach.

RESULTS

After screening 1748 relevant articles, 9 RCTs comparing SPG block with other interventions (6 conservative treatments, 1 sham, 1 GON and 1 intranasal lidocaine puff) were included in this meta-analysis. SPG block demonstrated superiority over conservative treatment in pain reduction at 30 min, 1 h, 2 h, 4 h after interventions and treatment failures with "very low" to "moderate" quality of evidence. The SPG block failed to demonstrate superiority over conservative treatment in pain reduction beyond 6 h, need for rescue treatment, and adverse events. SPG block demonstrated superiority over intranasal lignocaine puff in pain reduction at 30 min, 1 h, 6 h, and 24 h after interventions. SPG block did not show superiority or equivalence in all efficacy and safety outcomes as compared to sham and GON block.

CONCLUSION

Very Low to moderate quality evidence suggests the superiority of SPG block over conservative treatment and lignocaine puff for short-term pain relief from PDPH.

PROSPERO REGISTRATION

CRD42021291707.

Neuromodulation for the Sphenopalatine Ganglion-a Narrative Review

PURPOSE OF REVIEW

To provide an integrated overview of the current state of knowledge of neuromodulation for the sphenopalatine ganglion (SPG) by reviewing relevant and significant literature.

RECENT FINDINGS

There are several case reports and clinical trials evaluating neuromodulation for the SPG. We identified two blinded, randomized clinical trials for patients with chronic cluster headache. The randomized trials and additional studies demonstrated the long-term safety, efficacy, and cost-effectiveness of neuromodulation for the SPG. Recent studies in Europe and the USA suggest that SPG neuromodulation is a novel modality with clinical importance for treating acute cluster headaches and reducing the frequency of attacks.

Reactivation of Herpes Simplex Virus Following Sphenopalatine Ganglion Nerve Block: Case Report and Review of the Literature

A 36-year-old woman with no significant past medical history underwent a sphenopalatine ganglion block for treatment of a month-long migraine headache refractory to conservative treatment protocols. The headache resolved initially, but 1 day following the procedure, the headache recurred. The patient also developed an erythematous and edematous rash which cultures confirmed to be herpes simplex virus (HSV). Following several unsuccessful treatment modalities, the patient received valacyclovir, which resulted in resolution of her headache. Underlying HSV-1 infection may cause intractable migraine headache and nerve blocks may potentiate reactivation of latent HSV infection that caused the skin lesion in this case.

Ocular involvement in sphenopalatin ganglion pulsed radiofrequency

Pulsed radiofrequency (PRF) treatment of the sphenopalatine ganglion is an important interventional treatment in refractory cases of trigeminal neuralgia (TN) or atypical facial pain, given the easy access to its location. Despite the fact that complications from this technique are rare and it is a fairly safe procedure, ophthalmologists should know about it due to the anatomical relations of this ganglion.

Non-Surgical Treatments of Trigeminal Neuralgia from the Perspective of a Pain Physician: A Narrative Review

Trigeminal neuralgia (TN) is a unilateral disorder characterized by electric shock-like pain, abrupt onset and termination, and limited to one or more branches of the trigeminal nerve. Various therapeutic modalities for TN have been introduced. We searched for literature indexed in PubMed, Medline, and the National Library of Medicine and reviewed all relevant articles on non-surgical treatments for TN. Published studies were reviewed with no restrictions on date; reviews, clinical trials, animal studies, retrospective studies, and cases were included. Carbamazepine and oxcarbazepine are the recommended first-line pharmacotherapies. Interventional treatments should be considered when pharmacotherapy is insufficient or withdrawn because of adverse effects.

Missed pituitary microadenoma during endoscopic transsphenoidal surgery for short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing with symptom relief: illustrative case

BACKGROUND

Short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT) is a rare headache disorder that has been associated with pituitary adenomas. Resection has been posited to be curative.

OBSERVATIONS

A 60-year-old female presented with a 10-year history of SUNCT, which had been medically refractory. Sellar magnetic resonance imaging (MRI) showed a 2 × 2 mm nodule in the right anterolateral aspect of the pituitary. Endoscopic endonasal transsphenoidal resection of the pituitary microadenoma with neuronavigation was performed. The patient felt immediate relief from the headaches. Postoperative MRI showed persistence of the pituitary microadenoma and the resection tract to be inferomedial to the lesion. The right middle and partial superior turbinectomy site was close to the sphenopalatine foramen (SPF). The patient was discharged on postoperative day 1 and remained headache-free without any medications at the 4-month follow-up.

LESSONS

Resection of pituitary lesions associated with SUNCT may not necessarily be the cause of SUNCT resolution. Manipulation of the middle and superior turbinate close to the SPF may lead to a pterygopalatine ganglion block. This may be the mechanism of cure for SUNCT in patients with related pituitary lesions who undergo endonasal resection.

Symptoms and pathophysiology of cluster headache. Approach to combined occipital and supraorbital neurostimulation

Cluster headache (CH) is included under section 3 - Trigeminal autonomic cephalalgias (TAC) of the International Headache Society (IHS) classification. It is one of the most frequent, painful and disabling primary headaches. Acute and preventive pharmacological treatments are often poorly tolerated and of limited effectiveness. Due to improved understanding of the pathophysiology of CH, neuromodulation devices are now considered safe and effective options for preventive and acute treatment of CH. In this paper, we review the information available to date, and present the case of a patient with disabling cluster headache highly resistant to medical treatment who underwent implantation of a peripheral nerve neurostimulation system to stimulate the supraorbital nerves (SON) and greater occipital nerve (GON) in our Pain Unit. We also review the diagnostic criteria for CH, the state of the knowledge on the pathophysiology of CH, and the role played by neuromodulation in treating this condition.

Evaluation of the efficacy of therapeutic ultrasound in the treatment of migraine

Objectives

This study aims to evaluate the efficacy of therapeutic pulsed ultrasound (US) applied to the occipital nerve distribution area in chronic migraine patients.

Patients and methods

This prospective, randomized, double-blind, placebo-controlled, study was conducted on 58 patients diagnosed with migraine at the University of Health Sciences Bursa Yüksek Ihtisas Training and Research Hospital, Department of Physical Medicine and Rehabilitation between January 2018 and October 2018. The patients were randomly divided into two groups as sham and pulsed US group. Pulsed US was applied in Group 1 (n=29), and sham US was used in Group 2 (n=29) for 5 min for a total of 10 sessions in each group. The evaluation was made at pre-treatment, post-treatment first month (week six) and third month (week 14) using the numeric rating scale, and the Migraine Disability Assessment Scale (MIDAS). The final analysis was conducted with 52 patients (7 males, 45 females; mean age: 38.3±7.9 years; range, 20 to 65 years) due to drop-outs, with 27 patients in Group 1 and 25 patients in Group 2.

Results

A statistically significant improvement was found in all parameters at week six and week 14 compared to pre-treatment values in Group 1. A statistically significant worsening was detected in MIDAS 1, 4, 5, total questions, and a significant improvement was found in MIDAS A and B at week six compared to pre-treatment values in Group 2. A statistically significant worsening was found only in MIDAS total score at week 14 compared to pre-treatment values. In the comparison of the difference scores of the two groups, all parameters in Group 1 showed significant improvement at week six and week 14.

Conclusion

The findings obtained in this study show that pulsed US applied to the occipital nerve distribution region in migraine patients can be effective on headache frequency, severity, and disability.

Role of Computed Tomography and Magnetic Resonance Imaging in the Evaluation of Headache Due to Paranasal Sinus and Teeth Disorder

When brain imaging is performed as a first-line investigation for headaches and no intracranial abnormality is found, attention should always be paid to potential non-CNS causes of headache including paranasal sinus inflammatory, infectious, and occasionally malignant disease, and also to odontogenic sinusitis. Non-enhanced CT (NECT) head offers an initial evaluation of these areas which may be an unexpected source of symptomatology. Further imaging may then be required with either dedicated sinus NECT [particularly if surgical intervention is necessary for paranasal sinus disease], a contrast-enhanced (CECT) head and sinus CT, or an MRI if intracranial complications of sinonasal disease or acute invasive fungal sinusitis is suspected.

Agents Used for Nerve Blocks and Neurolysis

The recognition of pain and the treatments used for it are vital for all practitioners. Many types of pain can be treated in a locoregional fashion, which has significant implications not just for any individual patient but for society as a whole. These treatments are most effective when performed in a minimally invasive, image-guided fashion. Interventional radiologists should play a central role in providing these lifestyle-limiting treatments. This article describes the medications most typically used for spinal and extra-axial treatments in the management of patients in pain.

Postdural Puncture Headache-Risks and Current Treatment

PURPOSE OF REVIEW

This manuscript aims to review the risks and the current treatments for postdural puncture headache (PDPH).

RECENT FINDINGS

PDPH is a relatively frequent complication after neuraxial blocks. It is typically orthostatic in nature, presenting as a positional and dull aching or throbbing headache, with added dysregulation of auditory and/or visual signals. Certain characteristics, such as female sex and young age, may predispose patients to the development of PDPH, as may factors such as previous PDPH, bearing down during the second stage of labor, and the neuraxial technique itself. Long-term complications including chronic headache for years following dural puncture have brought into question of the historical classification of PDPH as a self-limiting headache. So far, the underlying mechanism governing PDPH remains under investigation, while a wide variety of prophylactic and therapeutic measures have been explored with various degree of success. In case of mild PDPH, conservative management involving bed rest and pharmacological management should be used as first-line treatment. Nerve blocks are highly efficient alternatives for PDPH patients who do not respond well to conservative treatment. In case of moderate-to-severe PDPH, epidural blood patch remains the therapy of choice. An interdisciplinary approach to care for patients with PDPH is recommended to achieve optimal outcomes.

Multimodal transcutaneous auricular vagus nerve stimulation: An option in the treatment of sleep bruxism in a "polyvagal" context

OBJECTIVE

To consider the possible role of the vagus nerve (VN) in the pathophysiology of sleep bruxism (SB) and introduce a multimodal protocol of transcutaneous auricular stimulation of the VN in the treatment of SB patients.

METHODS

Ten patients with SB underwent four sessions of electric transcutaneous auricular vagus nerve stimulation (ta-VNS) in specific auricular areas. The patients were advised to manually stimulate the same areas between sessions. Masticatory muscle activity and sleep parameters were measured by a polysomnography (PSG) before and after the treatment. Heart rate variability (HRV) parameters were measured during each stimulation.

RESULTS

PSG analysis revealed a statistically significant reduction in tonic SB index and tonic contraction time. HRV parameters showed a statistically significant increase in mean values of the vagal tone after each session of stimulation. No side effect was reported.

CONCLUSION

The stimulation of the VN might have a role in the treatment of SB.

A Narrative Review of Therapeutic Peripheral Nerve Blocks for Chronic Orofacial Pain Conditions

AIMS

To provide an analysis of the different therapeutic peripheral nerve blocks (PNBs), as well as their limitations and the related evidence base for their use in chronic orofacial pain (OFP) conditions, excluding migraine and other headache conditions.

METHODS/RESULTS

The evidence base for therapeutic PNBs for chronic OFP is poor and highlights the need for improved research in this area. The diagnostic criteria and interventional PNB definitions and techniques varied between studies. In addition, the placebo effect of a peripheral injection and its resultant bias was rarely considered. Most of the PNB interventions for temporomandibular disorders were for arthrogenous disorders (arthritis and disc entrapment with pain). However, there is emerging evidence for the use of onabotulinum toxin (BTX-A) in trigeminal neuralgia, with four prospective randomized controlled trials (pRCTs), and for postherpetic neuralgia. However, despite high-level evidence for BTX-A in posttraumatic neuropathic pain outside the trigeminal system, there is no evidence for its use for PTNP within the trigeminal system.

CONCLUSION

There may be emerging evidence for treating trigeminal neuralgia with BTX-A injections; however, there is a need for future clinical studies of therapeutic PNBs in orofacial pain conditions.

Transnasal sphenopalatine ganglion block for postdural puncture headache in obstetric patients: A Malaysian experience report

Postdural puncture headache (PDPH) is a common complication among obstetric patients after neuraxial anaesthesia. Conservative management may be associated with compliance issues, whereas the gold standard treatment, the epidural blood patch, is invasive and can result in serious complications. Transnasal sphenopalatine ganglion (SPG) block has recently emerged as a non-invasive treatment modality for PDPH. We describe our experience in performing transnasal SPG block by using modified techniques and different drug regimens at our centre. Dexamethasone was used as an adjuvant in transnasal SPG block for PDPH and has not been reported in other studies. Our first patient showed complete resolution of PDPH, and our second patient had a partially resolved headache subsequently requiring an epidural blood patch.

Stimulating the Facial Nerve to Treat Ischemic Stroke: A Systematic Review

Acute ischemic stroke (AIS) is a common devastating disease that has increased yearly in absolute number of cases since 1990. While mechanical thrombectomy and tissue plasminogen activator (tPA) have proven to be effective treatments, their window-of-efficacy time is very short, leaving many patients with no viable treatment option. Over recent years there has been a growing interest in stimulating the facial nerves or ganglions to treat AIS. Pre-clinical studies have consistently demonstrated an increase in collateral blood flow (CBF) following ganglion stimulation, with positive indications in infarct size and neurological scores. Extensive human trials have focused on trans-oral electrical stimulation of the sphenopalatine ganglion, but have suffered from operational limitations and non-significant clinical findings. Regardless, the potential of ganglion stimulation to treat AIS or elongate the window-of-efficacy for current stroke treatments remains extremely promising. This review aims to summarize results from recent trial publications, highlight current innovations, and discuss future directions for the field. Importantly, this review comes after the release of four important clinical trials that were published in mid 2019.

Does TENS Reduce the Intensity of Acute and Chronic Pain? A Comprehensive Appraisal of the Characteristics and Outcomes of 169 Reviews and 49 Meta-Analyses

Background and Objectives: Uncertainty about the clinical efficacy of transcutaneous electric nerve stimulation (TENS) to alleviate pain spans half a century. There has been no attempt to synthesise the entire body of systematic review evidence. The aim of this comprehensive review was to critically appraise the characteristics and outcomes of systematic reviews evaluating the clinical efficacy of TENS for any type of acute and chronic pain in adults. Materials and Methods: We searched electronic databases for full reports of systematic reviews of studies, overviews of systematic reviews, and hybrid reviews that evaluated the efficacy of TENS for any type of clinical pain in adults. We screened reports against eligibility criteria and extracted data related to the characteristics and outcomes of the review, including effect size estimates. We conducted a descriptive analysis of extracted data. Results: We included 169 reviews consisting of eight overviews, seven hybrid reviews and 154 systematic reviews with 49 meta-analyses. A tally of authors' conclusions found a tendency toward benefits from TENS in 69/169 reviews, no benefits in 13/169 reviews, and inconclusive evidence in 87/169 reviews. Only three meta-analyses pooled sufficient data to have confidence in the effect size estimate (i.e., pooled analysis of >500 events). Lower pain intensity was found during TENS compared with control for chronic musculoskeletal pain and labour pain, and lower analgesic consumption was found post-surgery during TENS. The appraisal revealed repeated shortcomings in RCTs that have hindered confident judgements about efficacy, resulting in stagnation of evidence. Conclusions: Our appraisal reveals examples of meta-analyses with 'sufficient data' demonstrating benefit. There were no examples of meta-analyses with 'sufficient data' demonstrating no benefit. Therefore, we recommend that TENS should be considered as a treatment option. The considerable quantity of reviews with 'insufficient data' and meaningless findings have clouded the issue of efficacy. We offer solutions to these issues going forward.

Change in opioid and analgesic use for headaches after aneurysmal subarachnoid hemorrhage over time

BACKGROUND

Severe headache, a hallmark of aneurysmal subarachnoid hemorrhage (aSAH), affects up to 90% of patients during hospitalization. Opioids remain the guideline recommended mainstay of acute therapy despite their significant side effects and potential for tolerance and addiction. We evaluated time trends in opioid prescriptions, hypothesizing a decline with increasing recognition of the opioid crisis.

METHODS

We performed a retrospective review of patients with aSAH admitted to a single tertiary care center between 2012 and 2019 and included patients with Hunt-Hess-Grade≤3 who were able to verbalize pain scores. Collected variables included mean and maximum daily headache scores, aneurysm treatment modality, and daily analgesic medication doses.

RESULTS

Of 340 patients with aSAH, 114 (86 from 2012-2016 and 28 from 2017-2019) were included. Of the included patients, 86/114 (75.4%) were female. Patients in the 2012-2016 had a median age of 55 compared to 63 in the 2017-2019 group (P=0.02). Otherwise, there was no significant difference in demographic data including time in hospital, treatment option utilized, or aneurysm characteristics. Maximal daily headache score ranged from 6 to 8 for 2012-2016 and 5 to 8 for 2017-2019 cohorts. Average oral morphine equivalents (in mg) administered during hospitalization were similar between groups (2012-2016: 251±345 95% CI [178,323]; 2017-2019: 207±237 95% CI [119,295]; P=0.319). When prescribed, doses of opioids provided at discharge were less in the more recent group (2012-2016: 84.4±78.9 95% CI [57.5, 111]; 2017-2019: 38.1±20.2 95% CI [33.7, 42.5]; P=0.004) CONCLUSION: Despite recognition of important drawbacks of opioid use for headache control, and efforts to reduce opioid use during hospitalization, we found that utilization during hospitalization for SAH did not decrease over time. Maximal headache scores remained similar in the studied time periods, indicative of insufficient pain relief. This points out a pressing need to further investigate alternative opioid and narcotic sparing strategies for patients with SAH.

Gamma Knife radiosurgery for cluster-tic syndrome unresponsive to medical treatment: illustrative case

BACKGROUND

Cluster-tic syndrome is a disorder characterized by the coexistence of symptoms related to both cluster headache and trigeminal neuralgia. Etiopathogenesis is not yet well defined. Medical treatment, including drugs for both cluster headache and trigeminal neuralgia, is the first therapeutic choice, whereas more invasive treatments are indicated in the case of pharmacological therapy failure or in the presence of drug side effects. To date, no randomized and/or large cohort trials describing Gamma Knife radiosurgery (GKRS) for cluster-tic syndrome are available, probably due to the syndrome’s rarity.

OBSERVATIONS

The authors describe the case of a 76-year-old woman with refractory cluster-tic syndrome who underwent GKRS with double target (the retrogasserian portion of the trigeminal nerve and the sphenopalatine ganglion). The Numerical Rating Scale (NRS) of pain and the Barrow Neurological Institute (BNI) pain intensity score before treatment were 7 (up to 10 during paroxysmal pain attacks) and V, respectively. At last follow-up, 24 months after GKRS, the patient had discontinued her pain medications and NRS and BNI pain scores were 1 and I, respectively. No trigeminal sensory disorders were reported.

LESSONS

The present case shows that GKRS, in selected cases, could be an effective treatment in patients with refractory cluster-tic syndrome.

Transnasal Sphenopalatine Ganglion Block for the Preventive Treatment of Chronic Daily Headache in Adolescents

Chronic headaches are a major source of morbidity in the pediatric population, affecting physical function, school attendance, social capacity, mood, and sleep. In adults, repetitive sphenopalatine ganglion (SPG) blockade has been studied as a preventive treatment for chronic migraines. This case series aims to evaluate the SPG block for the preventive treatment of chronic daily headache (CDH) in adolescents. We prospectively evaluated 17 adolescents (14 females, 14 ± 1 year) with CDH not responding to cognitive behavioral therapy (CBT), physiotherapy, and standard medications. Each patient received 10 SPG blocks (two blocks/week) using the Tx360® device. At the end of treatment, 10 patients (59%) reported a Patient's Global Impression of Change (PGIC) score ≥ 67%, and 3 months after the end of treatment, nine patients (53%) sustained a PGIC ≥ 67%. There was also a statistically significant reduction in the depression subscale of the Revised Children's Anxiety and Depression Scale (RCADS) at the end of treatment and 3 months post-treatment compared with baseline. The procedure was well tolerated with no adverse effects. In our study, the use of repeat SPG blockade was associated with sustained benefits on the PGIC and the depression subscale of the RCADS when used as preventive headache treatment in adolescents with refractory CDH.

Sphenopalatine ganglion block for refractory COVID-19 headache: a descriptive case series

Coronavirus SARS-CoV-2 is responsible for the COVID-19 pandemic, and headache is reported in 6.5% to 34% of all cases. There is little published evidence on the pharmacological treatment of COVID-19 headache. This case series presents six COVID-19 infected patients with refractory headache in which intranasal bedside Sphenopalatine Ganglion Block was performed for analgesia. All patients had a reduction in headache intensity from severe to mild or no pain after the procedure with minor transient side effects. Proposed mechanisms of action include reduction of local autonomic stimuli, intracranial vasoconstriction, and reduction of vasoactive substances release in the pterygopalatine fossa.

Control of Hemodynamic Responses and Perioperative Outcomes in Transsphenoidal Pituitary Surgery: A Qualitative Systematic Review of the Available Evidence

Transnasal transsphenoidal (TNTS) pituitary surgery is associated with short-lived but intense nociceptive stimuli which cause substantial hemodynamic perturbations that may increase blood loss and impair visualization of the surgical field. This systematic review aimed to critically appraise the clinical evidence for the efficacy and safety of various anesthetic techniques, other pharmacological modalities, and supplementary interventions by assessing intraoperative systemic hemodynamics, use of adjunct medications, quality of the surgical field, intraoperative blood loss, and recovery profiles in patients undergoing TNTS pituitary surgery. Relevant randomized clinical trials and observational studies were identified in a systematic literature search; 16 studies (13 randomized clinical trials, 3 observational studies) enrolling a total of 907 patients were identified for inclusion in this review. Propofol provided more potent hemodynamic control compared with volatile anesthetics with a sparing effect on the need for additional drugs to blunt hemodynamic responses. Recovery profiles between propofol and sevoflurane were either equivalent or favored sevoflurane, but both agents were superior to isoflurane. Regarding intraoperative analgesia, remifentanil was associated with superior hemodynamic control and recovery profiles than fentanyl. Dexmedetomidine had beneficial effects on hemodynamics, surgical field quality, recovery characteristics, and nociceptive properties compared with placebo. Although there was no clear-cut superiority of other adjunct pharmacological modalities on hemodynamic responses during surgery, regional blocks were associated with beneficial impacts on both primary and secondary outcomes. In summary, short-acting anesthetics, analgesics and dexmedetomidine seem to improve intraoperative hemodynamics, blood loss, and recovery qualities during TNTS pituitary surgery. However, definitive conclusions cannot be drawn because of methodological heterogeneity in the identified studies.

Pterygopalatine Fossa Blockade as Novel, Narcotic-Sparing Treatment for Headache in Patients with Spontaneous Subarachnoid Hemorrhage

BACKGROUND

Severe headache is a hallmark clinical feature of spontaneous subarachnoid hemorrhage (SAH), affecting nearly 90% of patients during index hospitalization, regardless of the SAH severity or presence of a culprit aneurysm. Up to 1 in 4 survivors of SAH experience chronic headaches, which may be severe and last for years. Data guiding the optimal management of post-SAH headache are lacking. Opioids, often in escalating doses, remain the guideline-recommended mainstay of acute therapy, but pain relief remains suboptimal.

METHODS

This study is a case series of adult patients who received bilateral pterygopalatine fossa (PPF) blockade for the management of refractory headaches after spontaneous SAH (aneurysmal and non-aneurysmal) at a single tertiary care center. We examined pain scores and analgesic requirements before and after block placement.

RESULTS

Seven patients (median age 54 years, 3 men, four aneurysmal and three non-aneurysmal) received a PPF-block between post-bleed day 6-11 during index hospitalization in the neurointensive care unit. The worst pain recorded in the 24-h period before the block was significantly higher than in the period 4 h after the block (9.1 vs. 3.1; p = 0.0156), and in the period 8 h after the block (9.1 vs. 2.8; p = 0.0313). The only complication was minor oozing from the needle insertion sites, which subsided completely with gauze pressure within 1 min.

CONCLUSIONS

PPF blockade might constitute a promising opioid-sparing therapeutic strategy for the management of post-SAH headache that merits further prospective controlled randomized studies.

The Efficacy of Sphenopalatine Ganglion Block and Radiofrequency Denervation in the Treatment of Cluster Headache: A Case Series

Background

Cluster headache is a variant of primary neurovascular headaches. some patients with cluster headache are not responsive to medical treatment and may benefit from interventional modalities, including sphenopalatine ganglion block and denervation.

Objectives

Our purpose was to evaluate the efficacy of sphenopalatine ganglion block/denervation in the treatment of cluster headache.

Methods

In this study, we performed the sphenopalatine ganglion block for patients with cluster headaches, intractable to medical therapy, who were referred to our pain clinic between 2014 and 2018. We registered the following information for all patients: demographic data, pain relief, and pain intensity. First, we conducted a prognostic C-arm-guided sphenopalatine ganglion block. If there was at least 50% pain relief within the first 5 h, then we denervated the ganglion by radiofrequency ablation. The main outcome of the study (dependent variable) was pain relief. We followed the patients for 6 months.

Results

Among 23 enrolled patients, 19 consented to interventional treatment. Fifteen out of 19 patients (79%) had an acceptable response to the prognostic block. Ultimately, 11 patients underwent ganglion denervation, and 4 patients did not consent for ganglion ablation. Pain relief at intervals of 48 h, and 1, 3, and 6 months after ganglion denervation was 77, 59, 50, and 31 percent, respectively.

Conclusions

Sphenopalatine ganglion conventional radiofrequency denervation can effectively decrease the pain intensity of the patients with cluster headache for at least several months.

Phantom eye syndrome. Case report and literature review

A frequent complication after limb amputation is the appearance of phantom limb syndrome, a phenomenon that has also been studied in the amputation of different body parts. Cases reported in relation to ophthalmologic surgery are few and evidence is limited in terms of specific management, which makes this a very important study. We report the case of a patient diagnosed with phantom eye syndrome in the post-operative period of an orbital exenteration surgery. A comprehensive approach was taken with multimodal symptom management, including intervention treatment. Significant improvement regarding the pain was achieved; however, non-painful ghost sensations persisted. Upon reviewing the available literature on the subject, its pathophysiology is not fully elucidated. Its incidence is highly variable, as well as the symptoms’ appearance. The presence of headache and eye pain prior to surgery seem to be risk factors. Climate and psychological stress are exacerbating factors of the symptomatology. No high-quality evidence was found in terms of management guidelines, with the use of antidepressants, anticonvulsants and opioids being the most recommended. Interventional management is an option according to the characteristics of the pain and associated symptoms.

Domain Heterogeneity in Radiofrequency Therapies for Pain Relief: A Computational Study with Coupled Models

The objective of the current research work is to study the differences between the predicted ablation volume in homogeneous and heterogeneous models of typical radiofrequency (RF) procedures for pain relief. A three-dimensional computational domain comprising of the realistic anatomy of the target tissue was considered in the present study. A comparative analysis was conducted for three different scenarios: (a) a completely homogeneous domain comprising of only muscle tissue, (b) a heterogeneous domain comprising of nerve and muscle tissues, and (c) a heterogeneous domain comprising of bone, nerve and muscle tissues. Finite-element-based simulations were performed to compute the temperature and electrical field distribution during conventional RF procedures for treating pain, and exemplified here for the continuous case. The predicted results reveal that the consideration of heterogeneity within the computational domain results in distorted electric field distribution and leads to a significant reduction in the attained ablation volume during the continuous RF application for pain relief. The findings of this study could provide first-hand quantitative information to clinical practitioners about the impact of such heterogeneities on the efficacy of RF procedures, thereby assisting them in developing standardized optimal protocols for different cases of interest.

The Effect of Sphenopalatine Ganglion Block on the Postoperative Pain in Patients Undergoing Septorhinoplasty

OBJECTIVES

This study aimed to evaluate the effect of preoperative sphenopalatine ganglion block (SPBG) on the postoperative pain (POP) in patients undergoing septorhinoplasty (SRP).

METHODS

A retrospective cohort study was performed. A total of 42 patients that had received septorhinoplasty included in the study. The patients that had received SPBG before the surgery included in the Block group (n:20) and the patients that had not received SPBG before the surgery included in the Control group (n:22). POP was questioned with a numeric rating scale (NRS) at the 30th minute (t1), 1st hour (t2), 4th hour (t3), 12th hour (t4), and 24th hour (t5) and noted. The intraoperative details and the dose of the postoperative rescue analgesics were also noted.

RESULTS

The average dose of Paracetamol that was used in the postoperative first 24 hours was 500 mg in the Block group and 1363 mg in the Control group, and the difference was statistically significant (P = .001). The average dose of Tramadol was 0 mg in the Block group and 45 mg in the Control group, and the difference was statistically significant (P = .001). There was a statistically significant difference among the groups with respect to NRS in the first 24 hours postoperatively (P < .05). The number of the patients requiring rescue analgesics was lower in the Block group than the Control group. The difference was statistically significant at the t1, t2, and t5 time intervals (P > .05).

CONCLUSIONS

Preoperative SPGB is an effective option to reduce POP and the need for rescue analgesics for patients undergoing SRP.

CLINICAL TRIAL NUMBER

NCT04020393.

Sphenopalatine Ganglion Blocks in the Management of Head and Neck Cancer-Related Pain: A Case Series

Head and neck cancer can be painful, debilitating, and refractory to oral medications. Due to the association of the sphenopalatine ganglion (SPG) with maxillary nerve sensory fibers, SPG blocks may be used to treat the pain of the hard and soft palate, tonsils, nasal cavity, paranasal sinuses, oral gingiva, premaxillary soft tissue, maxilla, and orbital floor. We present the first case series of performing SPG blocks utilizing TX360 nasal atomizers or angiocatheters to treat head and neck cancer-related pain. Pain scores were reduced by 38% to 80% with an average pain relief duration of 23 days.

Sphenopalatine ganglion block in primary headaches: An American Headache Society member survey

Background

The sphenopalatine ganglion (SPG), in the pterygopalatine fossa, is a known current and historical target for therapeutic intervention in headache disorders because of its role in cranial autonomics and vasodilation. There remains an overall lack of well-established SPG treatment protocols, particularly with the advent of newer commercial devices.

Methods

A 22 multiple-choice question survey was created to evaluate clinical practice patterns with SPG block and sent to members of the American Headache Society (AHS). Questions focused on determining indications, preferred applicators, medications applied, perceived efficacy, tolerability, and reimbursement.

Results

One hundred seventy-two of 1,346 (12.8%) AHS members participated. Ninety-three respondents (56.3%) had performed SPG blocks on 50 or fewer patients. The SphenoCath (42.4%) and the Tx360 (41.8%) were the most common methods of application. Ease of use was the top reason for provider preference in applicator type. SPG blocks were mostly used as an as-needed one-time procedure. When a scheduled protocol was used, twice weekly for 6 weeks was most common. Chronic migraine was the most commonly treated headache disorder and rated the most likely to respond to SPG block. Experienced clinicians found SPG more helpful as a stand-alone treatment and tended to report that acute relief was not predictive of enduring response.

Conclusions

The variety of responses strongly suggests that clinicians would benefit from formalized protocols for SPG blocks. More experienced clinicians may have developed individualized protocols that they feel are more effective. The lack of evidence-based protocols contribute to clinicians not performing SPG blocks more frequently.

Visualizing the trigeminovagal complex in the human medulla by combining ex-vivo ultra-high resolution structural MRI and polarized light imaging microscopy

A trigeminovagal complex, as described in some animals, could help to explain the effect of vagus nerve stimulation as a treatment for headache disorders. However, the existence of a trigeminovagal complex in humans remains unclear. This study, therefore investigated the existence of the trigeminovagal complex in humans. One post-mortem human brainstem was scanned at 11.7T to obtain structural (T1-weighted) and diffusion magnetic resonance images ((d)MR images). Post-processing of dMRI data provided track density imaging (TDI) maps to investigate white matter at a smaller resolution than the imaging resolution. To evaluate the reconstructed tracts, the MR-scanned brainstem and three additional brainstems were sectioned for polarized light imaging (PLI) microscopy. T1-weighted images showed hyperintense vagus medullar striae, coursing towards the dorsomedial aspect of the medulla. dMRI-, TDI- and PLI-images showed these striae to intersect the trigeminal spinal tract (sp5) in the lateral medulla. In addition, PLI images showed that a minority of vagus fibers separated from the vagus trajectory and joined the trigeminal spinal nucleus (Sp5) and the sp5. The course of the vagus tract in the rostral medulla was demonstrated in this study. This study shows that the trigeminal- and vagus systems interconnect anatomically at the level of the rostral medulla where the vagus fibers intersect with the Sp5 and sp5. Physiological and clinical utility of this newly identified interconnection is a topic for further research.

Chronic Headache: a Review of Interventional Treatment Strategies in Headache Management

PURPOSE OF THE REVIEW

To provide an overview of current interventional pain management techniques for primary headaches with a focus on peripheral nerve stimulation and nerve blocks.

RECENT FINDINGS

Despite a plethora of treatment modalities, some forms of headaches remain intractable to conservative therapies. Interventional pain modalities have found a niche in treating headaches. Individuals resistant to common regimens, intolerant to pharmaceutical agents, or those with co-morbid factors that cause interactions with their therapies are some instances where interventions could be considered in the therapeutic algorithm. In this review, we will discuss these techniques including peripheral nerve stimulation, third occipital nerve block (TON), lesser occipital nerve block (LON), greater occipital nerve block (GON), sphenopalatine block (SPG), radiofrequency ablation (RFA), and cervical epidural steroid injections (CESI). Physicians have used several interventional techniques to treat primary headaches. While many can be treated pharmacologically, those who continue to suffer from refractory or severe headaches may see tremendous benefit from a range of more invasive treatments which focus on directly inhibiting the painful nerves. While there is a plethora of evidence suggesting these methods are effective and possibly durable interventions, there is still a need for large, prospective, randomized trials to clearly demonstrate their efficacy.

Pilot Study of Injection of OnabotulinumtoxinA Toward the Sphenopalatine Ganglion for the Treatment of Classical Trigeminal Neuralgia

Background

The sphenopalatine ganglion (SPG) has previously been targeted in trigeminal neuralgia (TN), but its role in this condition has not been established.

Objective

To investigate the safety of injecting onabotulinumtoxinA (BTA) toward the SPG using the MultiGuide^® in 10 patients with refractory classical TN, and collect preliminary efficacy data.

Methods

Twenty‐five international units (IU) of BTA were injected toward the SPG in a prospective, open‐label study in 10 patients with refractory classical TN. All patients were recruited and treated on an out‐patient basis at St. Olav's University Hospital in Trondheim (Norway). Primary outcome: adverse events (AEs). Primary efficacy outcome: number of TN attacks at weeks 5‐8 after injection compared to baseline. A treatment responder was predefined as at least 50% reduction in the median number of attacks per day between baseline and weeks 5‐8. Other efficacy outcomes were intensity of attacks (numeric rating scale, 0 to 10) and functional level (1 to 4; 1 best and 4 worst) at weeks 5‐8 after injection compared to baseline. Percentage of the day with concomitant persistent pain was registered at baseline and at weeks 1‐4, 6, 8, and 12 after injection. Patient global impression of change (PGIC) was ascertained at month 3.

Results

For the primary endpoint, we analyzed data for all 10 patients. For efficacy outcomes we analyzed data for 9 patients (1 patient violated protocol). We registered 13 AEs, none of which were serious. The median number of TN attacks during the 4‐week baseline and weeks 5‐8 after injection was 5.5 (range: 1.0‐51.5) and 5 (range: 0‐225.0), respectively (P = .401). Four patients were treatment responders. The median intensity of attacks at baseline and weeks 5‐8 after injection was 6 (range: 3.0‐8.5) and 3 (range: 0.0‐9.0) respectively (P = .024). The median functional level at baseline was 2 (range: 1.0‐3.3) and at month 2, 1 (range 1.0‐4.0; P = .750). Median percentage of the day with concomitant persistent pain was 75% (minimum 37.5%, maximum 100%) at baseline and 18.75% (minimum 0%, maximum 100%) at week 8 (P = .023).

Conclusions

Injection of BTA toward the SPG using the MultiGuide^® in patients with TN appears to be safe and well tolerated. This study was negative for the main efficacy endpoint (reduction in the number of attacks from baseline to weeks 5‐8). Further studies examining the role of the SPG in TN are necessary.

Neuromuscular dentistry and the role of the autonomic nervous system: Sphenopalatine ganglion blocks and neuromodulation. An International College of Cranio Mandibular Orthopedics (ICCMO) position paper

The Sphenopalatine Ganglion (SPG) is known to play an integral role in the pathophysiology of a wide variety of orofacial pains involving the jaws, sinuses, eyes and the trigeminal autonomic cephalalgias. It supplies direct parasympathetic innervation to the trigeminal and facial nerves. Sympathetic innervation from the superior sympathetic chain passes thru the SPG to the trigeminal and facial nerves.This paper reviews relevant and significant literature on SPG Blocks and Neuromodulation published in peer reviewed medical and dental journals. Neuromuscular Dentistry employs ULF-TENS to relax musculature and simultaneously provide neuromodulation to the ganglion.Conclusion: The effects of ULF-TENS on the autonomic nervous system acts on the Limbic System and Hypothalamus (H-P-A) to address Axis II issues during neuromuscular dental procedures. It also directly affects the autonomic component of the trigeminal nerve involved in almost all headaches and migraines as well as the Myofascial and Joint disorders of TMD.

Multicentre, prospective, randomised, controlled, blinded-endpoint study to evaluate the efficacy and safety of pterygopalatine ganglion pulsed radiofrequency treatment for cluster headache: study protocol

INTRODUCTION

Single-centre reports on small groups of patients have shown that pterygopalatine ganglion pulsed radiofrequency treatment in patients with refractory cluster headache (CH) can quickly relieve pain without significant side effects. However, a randomised controlled trial is still necessary to evaluate whether pterygopalatine ganglion pulsed radiofrequency (PRF) treatment is a viable treatment option for patients with CH who are not responding to drug treatment.

METHODS AND ANALYSIS

This investigation is a multicentre, prospective, randomised, controlled, blinded-endpoint study. We will enrol 80 patients with CH who are not responding to medication. The enrolled patients will be randomly divided into two groups: the nerve block (NB) group and the PRF group. All patients will undergo CT-guided pterygopalatine ganglion puncture. A mixture containing steroids and local anaesthetics will be slowly injected into the patients in the NB group. The patients in the PRF group will be treated with PRF at 42°C for 360 s. After treatment, the duration of cluster periods; degree of pain during headache attacks; frequency of headache attacks; duration of each headache attack; dose of auxiliary analgesic drugs; duration of remission; degree of patient satisfaction; effectiveness rates at 1 day, 3 days, 1 week, 2 weeks, 1 month, 3 months, 6 months, and 1 year after the procedure; and intraoperative and postoperative adverse events will be compared between the two groups.

ETHICS AND DISSEMINATION

This study was approved by the institutional ethics committee of the Beijing Tiantan Hospital (approval number: KY 2018-027-02). The results of the study will be published in peer-reviewed journals, and the findings will be presented at scientific meetings.

TRIAL REGISTRATION NUMBER

NCT03567590; Pre-results.

Effect of Sphenopalatine Ganglion Block With Bupivacaine on Postoperative Pain in Patients Undergoing Endoscopic Sinus Surgery

Background

Postoperative pain is one of the most complications in endoscopic sinus surgery. We aimed to evaluate the effect of the sphenopalatine ganglion block (SPGB) with bupivacaine on postoperative pain in patients undergoing endoscopic sinus surgery.Methods and Materials: In this clinical trial, 40 patients who indicated functional endoscopic sinus surgery were selected and then divided into 2 parallel groups as intervention and control. The intervention group was received 1.5 mL of bupivacaine 0.5% (injected to sphenopalatine ganglion) and while control was injected 1.5 mL of normal saline at the same injection site. Also, the visual analogue scale (VAS) was recorded immediately after anesthesia, along with 6, 12, 24, 48 h, 7 days, and 21 days after the operation for all patients.

Results

Immediately after anesthesia, as well as 6, 12, and 24 h after the operation, VAS in the intervention group was significantly lower than in the control group (P < .05, for all). However, there were no significant differences between the 2 groups regarding VAS 48 h as well as 7 and 21 days after surgery (P > .05, for both). Also, the rescue analgesia in the intervention group was significantly lower than in the control group (P = .01).

Conclusion

SPGB with bupivacaine 0.5% (1.5 mL) was a simple, effective, safe, and noninvasive method for the management of postoperative pain in the patients undergoing endoscopic sinus surgery.

Sphenopalatine Ganglion Block and Radiofrequency Ablation: Technical Notes and Efficacy

Background: Sphenopalatine ganglion (SPG) blockade or lesioning can offer significant pain relief for cluster headaches (CHs) and a variety of other pain syndromes involving the head and face. Methods: We reviewed the literature on the efficacy of SPG block and radiofrequency ablation (RFA) using PubMed and Google Scholar. Results: The infrazygomatic technique can be used to directly access the SPG for injection of local anesthetic or lesioning using RFA. Important technical points to achieve these procedures are described. SPG blockade efficacy is supported by randomized controlled studies but SPG RFA is not. Conclusion: Targeting the SPG is a promising treatment option for refractory CHs. RFA and neuromodulation have the potential to offer long-term significant pain relief, but more randomized studies are needed to demonstrate their efficacy.

The Effect of Sphenopalatine Block on the Postoperative Pain of Endoscopic Sinus Surgery: A Meta-analysis

Objectives

The use of sphenopalatine ganglion block (SPGB) with a local anesthetic to decrease postoperative pain after endoscopic sinus surgery (ESS) is controversial. We investigated the role of a perioperative SPB to minimize postoperative pain related to ESS in patients with chronic sinusitis through a systematic review of the relevant literature.

Data Sources

PubMed, SCOPUS, Google Scholar, Embase, and the Cochrane Register of Controlled Trials.

Review Methods

We screened the relevant literature published before June 2018. Eight articles that compared perioperative SPGB (treatment group) with a placebo or no treatment (control group) were included for this analysis of the outcomes, which included perioperative morbidities in ESS. For quantitative variables, the standardized mean difference was applied to standardize and summate the results of the studies, and the odds ratio was used in outcome of incidence analysis.

Results

Intraoperative bleeding ( P < .0001), postoperative pain ( P = .0001), nausea and vomiting ( P = .0117), and recovery from sedation ( P < .0001) in the treatment group were significantly reduced compared with the control group. No significant adverse effects were reported in the enrolled studies. In subgroup analyses according to the SPGB approach (transoral or transnasal), the transnasal approach showed higher positive effects on intraoperative bleeding and postoperative pain compared to the transoral approach.

Conclusion

In our study, SPGB combined with a local anesthetic for ESS effectively reduced intra-and postoperative morbidities. This procedure showed no significant adverse effects. Given the ease and effectiveness of this procedure, the transnasal approach should be highly recommended as a routine procedure compared to the transoral approach.

Radiofrequency techniques to treat chronic knee pain: a comprehensive review of anatomy, effectiveness, treatment parameters, and patient selection

Background

The use of radiofrequency ablation (RFA) procedures to treat chronic knee pain has surged in the past decade, though many questions remain regarding anatomical targets, selection criteria, and evidence for effectiveness.

Methods

A comprehensive literature review was performed on anatomy, selection criteria, technical parameters, results of clinical studies, and complications. Databases searched included MEDLINE and Google Scholar, with all types of clinical and preclinical studies considered.

Results

We identified nine relevant clinical trials, which included 592 patients, evaluating knee RFA for osteoarthritis and persistent postsurgical pain. These included one randomized, placebo-controlled trial, one randomized controlled trial evaluating RFA as add-on therapy, four comparative-effectiveness studies, two randomized trials comparing different techniques and treatment paradigms, and one non-randomized, controlled trial. The results of these studies demonstrate significant benefit for both reduction and functional improvement lasting between 3 and 12 months, with questionable utility for prognostic blocks. There was considerable variation in the described neuroanatomy, neural targets, radiofrequency technique, and selection criteria.

Conclusion

RFA of the knee appears to be a viable and effective treatment option, providing significant benefit to well-selected patients lasting at least 3 months. More research is needed to better identify neural targets, refine selection criteria to include the use of prognostic blocks, optimize treatment parameters, and better elucidate relative effectiveness compared to other treatments.

Cluster headache: new targets and options for treatment

Cluster headache is a severe headache disorder with considerable impact on quality of life. The pathophysiology of the disease remains poorly understood. With few specific targets for treatment, current guidelines mainly include off-label treatment with medication. However, new targets for possible treatment options are emerging. Calcitonin gene-related peptide (CGRP)-targeted medication could become the first (cluster) headache-specific treatment option. Other exciting new treatment options include invasive and non-invasive neuromodulation techniques. Here, we provide a short overview of new targets and treatment options that are being investigated for cluster headache.