Transorbital Endoscopic Approach to the Foramen Rotundum for Infraorbital Nerve Stripping.

PURPOSE: To develop and evaluate a transorbital endoscopic approach to the foramen rotundum to excise the maxillary nerve and infraorbital nerve branch. METHODS: Cadaveric dissection study of 10 cadaver heads (20 orbits). This technique is predicated upon 1) an inferior orbital fissure release to facilitate access to the orbital apex and 2) the removal of the posterior maxillary wall to enter the pterygopalatine fossa (PPF). Angulations along the infraorbital nerve were quantified as follows: the first angulation was measured between the orbitomaxillary segment within the orbital floor and the pterygopalatine segment suspended within the PPF, while the second angulation was taken between the pterygopalatine segment and maxillary nerve as it exited the foramen rotundum. With refinement of the technique, the minimum amount of posterior maxillary wall removal was quantified in the final 5 cadaver heads (10 orbits). RESULTS: The mean distance from the inferior orbital rim to the foramen rotundum was 45.55 ± 3.24 mm. The first angulation of the infraorbital nerve was 133.10 ± 16.28 degrees, and the second angulation was 124.95 ± 18.01 degrees. The minimum posterior maxillary wall removal to reach the PPF was 11.10 ± 2.56 mm (vertical) and 11.10 ± 2.08 mm (horizontal). CONCLUSIONS: The transorbital endoscopic approach to an en bloc resection of the infraorbital nerve branch up to its maxillary nerve origin provides a pathway to the PPF. This is relevant for nerve stripping in the context of perineural spread. Other applications include access to the superior portion of the PPF in selective biopsy cases or in concurrent orbital pathology.

Sphenopalatine Ganglion Stimulation for Chronic Headache Syndromes.

Neuropathic facial pain is notoriously difficult to treat, regardless of its origin and duration. Since the first reported sphenopalatine ganglion blockade by Sluder in 1908, this ganglion has assumed an important role among the structures targeted for the treatment of facial pain. Recent years have witnessed the rise of neuromodulation over ablative procedures, including the development of an implantable stimulation device specially designed for use in the pterygopalatine fossa. Sphenopalatine ganglion stimulation has been demonstrated as effective and safe for refractory cluster headache, today the major indication for this therapy, but increasing evidence shows that the effect on the autonomic system and cerebral circulation could justify an even wider use of sphenopalatine ganglion stimulation for other chronic headache syndromes and vascular diseases.

Sphenopalatine Ganglion Pulsed Radiofrequency for the Treatment of Refractory Chronic SUNCT and SUNA: A Prospective Case Series.

OBJECTIVES: We aimed to evaluate the safety and effectiveness of sphenopalatine ganglion pulsed radiofrequency (SPG-PRF) for the treatment of patients with refractory chronic short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT) and with cranial autonomic symptoms (SUNA). BACKGROUND: SPG-PRF is a minimally invasive, non-neurodestructive procedure already tested in refractory chronic cluster headache with mixed outcomes. However, no data have been produced in SUNCT/SUNA. METHODS: This was a prospective clinical audit of outcomes. Consecutive patients with chronic SUNCT/SUNA refractory to medical treatments and treated with SPG-PRF, were included in the analysis. The SPG-PRF was performed percutaneously via a lateral, infra-zygomatic approach. Responders were defined as patients with a reduction in number and/or severity of headache episodes by ≥30% for ≥3 months. Responders to the first procedure were offered to have the treatment repeated. RESULTS: Nine patients (6 female) were analyzed. After a median follow-up of 30 months (range 2-30), 7 patients were considered responders to the treatment (77.8%) for a median of 6 months (range: 4-10), 1 patient obtained 40% improvement for 2 months, and 1 patient did experience any improvement. No procedure-related immediate or delayed side effects were reported. Three patients (33.3%) experienced a worsening of the head pain for 2-4 weeks immediately after the procedure. Four responders had SPG-PRF repeated; a reproducible response was obtained in two of them. CONCLUSIONS: In our small series of patients with refractory chronic SUNCT/SUNA, SPG-PRF was a safe and effective treatment modality. The potential reproducible positive effect of subsequent treatments may prevent or delay the use of more invasive and costly interventions for at least a proportion of these patients.

Endoscopic prelacrimal approach to lateral recess of sphenoid sinus: feasibility study.

BACKGROUND: Various pathologies, including cerebrospinal fluid leaks and meningoencephaloceles, may arise in the lateral recess of the sphenoid sinus (LRSS), which may be accessed via an endonasal transpterygoid approach. The objective of this study was to evaluate the feasibility of accessing the LRSS via an endoscopic prelacrimal approach. Furthermore, we hypothesized that this approach may protect the pterygopalatine ganglion and vidian nerve. METHODS: Five cadaveric heads (9 sides) with a well-pneumatized LRSS were identified and an endonasal prelacrimal approach was performed. The infraorbital nerve, at the orbital floor, served as a critical landmark. After identification of the foramen rotundum at the pterygoid base, the vascular compartment of the pterygopalatine fossa and the pterygopalatine ganglion were displaced inferomedially and superomedially, respectively. Drilling of the bone inferomedial to the foramen rotundum allowed entry into the LRSS. RESULTS: The average distances from the prelacrimal window to the pterygoid base and the posterior wall of the LRSS were 6.22 ± 0.39 cm and 7.16 ± 0.50 cm, respectively. The average areas of the bony prelacrimal window and pterygoid base window were 4.33 ± 0.32 cm2 and 0.73 ± 0.10 cm2 , respectively. The LRSS could be accessed using a 0-degree endoscope, and pterygopalatine neurovascular structures, including the pterygopalatine ganglion and vidian nerve, could be preserved on all 9 sides. CONCLUSION: Our findings suggest that an endonasal prelacrimal approach provides a reasonable alternative to access the LRSS while preserving the vidian nerve and pterygopalatine ganglion.

Sphenopalatine ganglion stimulation is a reversible and frequency-dependent modulator of the blood-brain barrier.

BACKGROUND: The sphenopalatine ganglion (SPG) is a vasoactive mediator of the anterior intracranial circulation in mammals. SPG stimulation has been demonstrated to alter blood-brain barrier (BBB) permeability, although this phenomenon is not well characterized. OBJECTIVE: To determine the effect of SPG stimulation on the BBB using rat models. METHODS: Extravasation of fluorescent tracer 70 kDa FITC-dextran into rat brain specimens was measured across a range of stimulation parameters to assess BBB permeability. Tight junction (TJ) morphology was compared by assessing differences in the staining of proteins occludin and ZO-1 and analyzing ultrastructural changes on transmission electron microscopy (TEM) between stimulated and unstimulated specimens. RESULTS: SPG stimulation at 10 Hz maximally increased BBB permeability, exhibiting a 6-fold increase in fluorescent traceruptake (1.66% vs 0.28%, p < 0.0001). This effect was reversed 4-hours after stimulation (0.36% uptake, p = 0.99). High-frequency stimulation at 20 Hz and 200 Hz did not increase tracer extravasation, (0.26% and 0.28% uptake, p = >0.999 and p = 0.998, respectively). Stimulation was associated a significant decrease in the colocalization of occludin and ZO-1 with endothelial markers in stimulated brains compared to control (74.6% vs. 39.7% and 67.2% vs. 60.4% colocalization, respectively, p < 0.0001), and ultrastructural changes in TJ morphology associated with increased BBB permeability were observed on TEM. CONCLUSION: This study is the first to show a reversible, frequency-dependent increase in BBB permeability with SPG stimulation and introduces a putative mechanism of action through TJ disruption. Bypassing the BBB with SPG stimulation could enable new paradigms in delivering therapeutics to the CNS. Further study of this technology is needed.

Depicting the pterygopalatine ganglion on 3 Tesla magnetic resonance images.

PURPOSE: The pterygopalatine ganglion has yet not been identified on medical images in living humans. The primary aim of this study was to evaluate whether the pterygopalatine ganglion could be identified on 3 T MR imaging. METHODS: This study was performed on medical images of 20 Caucasian subjects on both sides (n = 40 ganglia) with an exploratory design. 3 T MR images were assessed by two physicians for the presence and size of the pterygopalatine ganglion. The distance from the pterygopalatine ganglion to four bony landmarks was registered from fused MR and CT images. In an equivalence analysis, the distances were compared to those obtained in an anatomical cadaveric study serving as historical controls (n = 50). RESULTS: A structure assumed to be the pterygopalatine ganglion was identified on MR images in all patients on both sides by both physicians. The mean size was depth 2.1 ± 0.5 mm, width 4.2 ± 1.1 mm and height 5.1 ± 1.4 mm, which is in accordance with formerly published data. Equivalence of the measurements on MR images and the historical controls was established, suggesting that the structure identified on the MR images is the pterygopalatine ganglion. CONCLUSION: Our findings suggest that the pterygopalatine ganglion can be detected on 3 T MR images. Identification of the pterygopalatine ganglion may be important for image-guided interventions targeting the pterygopalatine ganglion, and has the potential to increase the efficacy, safety and reliability for these treatments.

Peripheral provocation of cranial autonomic symptoms is not sufficient to trigger cluster headache attacks.

Background Recently it has been suggested that low frequency stimulation of the sphenopalatine ganglion (SPG) may provoke cluster-like attacks in cluster headache (CH) patients. The question arises whether a robust activation of cranial autonomic symptoms is sufficient to trigger CH attacks. Methods Kinetic oscillation stimulation (KOS) of the nasal mucosa generates ipsilateral marked autonomic symptoms, among which lacrimation is quantitatively measurable. KOS was applied to 29 CH-patients, including both episodic and chronic course. We measured lacrimation at rest and during stimulation, and assessed CH attacks within 24 hours after the experiment. Results Autonomic symptoms including lacrimation were robust and significantly generated, compared to rest. Six patients were lost to follow-up, but did not develop an attack during their stay in the clinic. Of the remaining 23 patients, none developed an attack in the next 4 hours after stimulation, despite marked cranial autonomic symptoms during stimulation. Discussion Peripheral stimulation close to the SPG generated a strong parasympathetic response. However, this stimulation was not sufficient to induce CH attacks, which suggests that a central component is crucial to attack generation.

Cranial parasympathetic activation induces autonomic symptoms but no cluster headache attacks.

Background Low frequency (LF) stimulation of the sphenopalatine ganglion (SPG) may increase parasympathetic outflow and provoke cluster headache (CH) attacks in CH patients implanted with an SPG neurostimulator. Methods In a double-blind randomized sham-controlled crossover study, 20 CH patients received LF or sham stimulation for 30 min on two separate days. We recorded headache characteristics, cephalic autonomic symptoms (CAS), plasma levels of parasympathetic markers such as pituitary adenylate cyclase-activating polypeptide-38 (PACAP38) and vasoactive intestinal peptide (VIP), and mechanical detection and pain thresholds as a marker of sensory modulation. Results In the immediate phase (0-60 min), 16 (80%) patients experienced CAS after LF stimulation, while nine patients (45%) reported CAS after sham ( p = 0.046). We found no difference in induction of cluster-like attacks between LF stimulation (n = 7) and sham stimulation (n = 5) ( p = 0.724). There was no difference in mechanical detection and pain thresholds, and in PACAP and VIP plasma concentrations between LF and sham stimulation ( p ≥ 0.162). Conclusion LF stimulation of the SPG induced autonomic symptoms, but no CH attacks. These data suggest that increased parasympathetic outflow is not sufficient to induce CH attacks in patients. Study protocol ClinicalTrials.gov registration number NCT02510729.

Upper airway stabilization by osteopathic manipulation of the sphenopalatine ganglion versus sham manipulation in OSAS patients: a proof-of-concept, randomized, crossover, double-blind, controlled study.

BACKGROUND: Osteopathic manipulative treatment (OMT) of the sphenopalatine ganglion (SPG) is used empirically for the treatment of rhinitis and snoring and is thought to increase pharyngeal stability. This trial was designed to study the effects of this treatment on pharyngeal stability evaluated by critical closing pressure in obstructive sleep apnoea syndrome. METHODS: This single-centre, randomized, crossover, double-blind study compared active manipulation and sham manipulation of the SPG. Randomization was computer-generated. Patients each received one active manipulation and one sham manipulation at an interval of 21 days and were evaluated 30 min and 48 h after each session administered by a qualified osteopath. Neither the patients, nor the investigator performing the evaluations were informed about the order of the two techniques (double-blind). The primary endpoint was the percentage of responding patients presenting increased pharyngeal stability defined by a variation of critical closing pressure (Pcrit) of at least -4 cmH2O at 30 min. Secondary endpoints were the variation of Pcrit in absolute values, sleepiness and snoring. Others endpoints were lacrimation (Schirmer's test), induced pain, sensations experienced during OMT. RESULTS: Ten patients were included and nine (57 [50; 58] years, comprising 7 men, with an apnoea-hypopnoea index of 31.0 [25.5; 33.2]/h; (values are median [quartiles])) were analysed. Seven patients were analysed for the primary endpoint and nine patients were analysed for secondary endpoints. Five patients responded after active manipulation versus no patients after sham manipulation (p = 0.0209). Active manipulation induced more intense pain (p = 0.0089), increased lacrimation (ns) and more tactile, nociceptive and gustatory sensations (13 versus 1) compared to sham manipulation. No significant difference was observed for the other endpoints. CONCLUSIONS: Osteopathic manipulative treatment of the SPG may improve pharyngeal stability in obstructive sleep apnoea syndrome. This trial validates the feasibility of the randomized, controlled, double-blind methodology for evaluation of this osteopathic treatment. Studies on a larger sample size must specify the efficacy on the apnoea-hypopnoea index. TRIAL REGISTRATION: The study was retrospectively registered in the clinicaltrial.gov registry under reference NCT01193738 on 1st September 2010 (first inclusion May 19, 2010).

Chronic Bilateral Sphenopalatine Ganglion Stimulation for Intractable Bilateral Chronic Cluster Headache: A Case Report.

UNLABELLED: A cluster headache (CH) is an excruciating pain centered on the periorbital region and is accompanied by autonomic symptoms. Despite the best currently available medical therapy, many patients still suffer from these headaches. Some patients also experience CH with side shift of attacks, which makes treatment more difficult. In light of the pathophysiological mechanism of CH, the sphenopalatine ganglion (SPG) is a promising therapeutic target for its management. SPG ablation and non-ablation techniques have been the preferred treatment for CH in recent decades. However, few articles have reported the effectiveness of acute SPG stimulation for CH, and no studies have demonstrated the safety and efficacy of bilateral continuous SPG stimulation for CH. In this article, we report on a 59-year-old chronic cluster headache (CCH) patient who had side shifts of attacks and was treated with bilateral continuous SPG stimulation. The patient suffered from CCH for 9 years, and the intensity of pain and the frequency of attacks had gradually increased over time. At the time of admission, he experienced daily attacks. Medical therapy and SPG blocks were offered, but he only achieved transient pain relief. After a careful preoperative examination and discussion with the patient, we provided bilateral SPG stimulation. The electrode was implanted under C-arm fluoroscopic guidance. After continuous stimulation, the patient experienced significant reductions in headache severity. The frequency of attacks was reduced from daily to less than once per week. He also discontinued all of the related drugs that he was taking. This is the first report of bilateral continuous SPG stimulation for CCH. This report indicates that continuous SPG stimulation is a feasible therapeutic option for CCH. However, large-scale and long-term studies are required to elucidate the efficacy of SPG stimulation. KEY WORDS: Cluster headache, sphenopalatine ganglion, SPG, neuromodulation, side shift, stimulation.

Cost-effectiveness of stimulation of the sphenopalatine ganglion (SPG) for the treatment of chronic cluster headache: a model-based analysis based on the Pathway CH-1 study.

BACKGROUND: In the recent Pathway CH-1 study, on-demand stimulation of the sphenopalatine ganglion (SPG) by means of an implantable neurostimulation system was proven to be a safe and effective therapy for the treatment of chronic cluster headache. Our objective was to assess the cost-effectiveness of SPG stimulation in the German healthcare system when compared to medical management. METHODS: Clinical data from the Pathway CH-1 study were used as input for a model-based projection of the cost-effectiveness of SPG stimulation through 5 years. Medical management as the comparator treatment was modeled on the basis of clinical events observed during the baseline period of CH-1. The costs of treatment were derived from a previously published cluster headache costing study and 2014 medication, neurostimulator, and procedure costs. We computed the 5-year incremental cost-effectiveness ratio (ICER) in euros per quality-adjusted life year (QALY), with costs and effects discounted at 3 % per year. RESULTS: SPG stimulation was projected to add 0.325 QALYs over the study period, while adding €889 in cost, resulting in a 5-year ICER of €2,736 per QALY gained. Longer follow-up periods, higher baseline attack frequency, and higher utilization of attack-aborting medications led to overall cost savings. SPG stimulation was found either cost-effective or cost-saving across all scenarios investigated in sensitivity analyses. CONCLUSIONS: Our model-based analysis suggests that SPG stimulation for the treatment of chronic cluster headache, under the assumption of sustained therapy effectiveness, leads to meaningful gains in health-related quality of life and is a cost-effective treatment strategy in the German healthcare system.

Value of intra- and post-operative cone beam computed tomography (CBCT) for positioning control of a sphenopalatine ganglion neurostimulator in patients with chronic cluster headache.

INTRODUCTION: The objective of this study was to determine whether postoperative control of the neurostimulator placement within the pterygopalatine fossa (PPF) by means of 3-dimensional (3D) cone beam computed tomography (CBCT) was of therapeutic relevance compared to intraoperative CBCT imaging alone. MATERIAL AND METHODS: Immediately after implantation of the sphenopalatine ganglion (SPG) neurostimulator, intraoperative CBCT datasets were generated in order to visualize the position of the probe within the PPF. Postoperatively, all patients received a CBCT for comparison with intraoperatively acquired radiographs. RESULTS: Twenty-four patients with cluster headache (CH) received an SPG neurostimulator. In 4 patients, postoperative CBCT images detected misplacement not found in intraoperative CBCT. In 3 cases, electrode tips were misplaced into the maxillary sinus and in 1 case into the apex of the PPF superior to the suspected location of the SPG. Immediate revision with successful repositioning within 3 days was done in 2 patients and a deferred reimplantation in 1 patient within 6 months. One patient declined revision. CONCLUSION: We were able to demonstrate the clinical value of postoperative dental CBCT imaging with a wide region of interest (ROI) due to a superior image quality compared with that achieved with intraoperative medical CBCT. Although intraoperative 3D CBCT imaging of electrode placement is helpful in the acute surgical setting, resolution is, at present, too low to safely exclude misplacement, especially in the maxillary sinus. High-resolution postoperative dental CBCT allows rapid detection and revision of electrode misplacement, thereby avoiding readmission and recurrent tissue trauma.

Treatment of a subtype of trigeminal neuralgia with descending palatine neurotomy in the pterygopalatine fossa via the greater palatine foramen-pterygopalatine canal approach.

PURPOSE: To discuss an effective surgical treatment of a subtype of trigeminal neuralgia with descending palatine neuralgia of the maxillary division. METHOD: Nine patients, who suffered from trigeminal neuralgia with descending palatine neuralgia of the maxillary division, received neurotomy and avulsion of the descending palatine nerve in the pterygopalatine fossa via the greater palatine foramen-pterygopalatine canal approach. Seven of the patients had a recurrence of descending palatine neuralgia after they received treatment of maxillary neuralgia with neurotomy and avulsion of the infraorbital nerve; two patients were diagnosed with descending palatine neuralgia of the maxillary division in our department. Postoperative follow-up was conducted. RESULTS: Pain in the palate disappeared; all patients felt numb and paresthetic in the area innervated by the trigeminal nerve, with no pain. During the 3-36 months of follow-up, no recurrence occurred. CONCLUSIONS: Descending palatine neurotomy in the pterygopalatine fossa via the greater palatine foramen-pterygopalatine canal approach is a simple, safe and effective way to treat a subtype of trigeminal neuralgia--descending palatine neuralgia.

Endoscopic approach to the trigeminal nerve: an anatomic study.

OBJECTIVE: To describe an endoscopic perspective of the surgical anatomy of the trigeminal nerve. METHODS: Nine adult cadaveric heads were dissected endoscopically. RESULTS: Opening the pterygopalatine fossa is important because many key anatomical structures (V2, pterygopalatine ganglion, vidian nerve) can be identified and traced to other areas of the trigeminal nerve. From the pterygopalatine ganglion, the maxillary nerve and vidian nerve can be identified, and they can be traced to the gasserian ganglion and internal carotid artery. An anteromedial maxillectomy increases the angle of approach from the contralateral nares due to an increase in diameter of the piriform aperture, and provides excellent access to the mandibular nerve, the petrous carotid, and the cochlea. CONCLUSIONS: Identification of key anatomical structures in the pterygopalatine fossa can be used to identify other areas of the trigeminal nerve, and an anteromedial maxillectomy is necessary to expose the ipsilateral mandibular nerve and contralateral cranial level of the trigeminal nerve.

Pterygopalatine fossa segment neurectomy of maxillary nerve through maxillary sinus route in treating trigeminal neuralgia.

PURPOSE: To explore an effective surgical treatment for pain in the distribution area of the maxillary branch of trigeminal nerve (TN). MATERIALS AND METHODS: Twenty-six patients with pain in the distribution of the maxillary branch of TN were followed up after they had undergone pterygopalatine fossa segment neurectomy of maxillary nerve through maxillary sinus route. RESULTS: In all cases, the pain initially resolved after operation, with anaesthesia or paraesthesia in the operated side of the maxillary nerve-distributed area. After a mean follow-up period of 24 (range 3-36) months, 19 (73.08%) of the 26 patients had an excellent response, 5 (19.23%) had a good response, 2 (7.69%) had a fair response, and none (0%) had a poor response. One patient had a recurrence with palatal pain 3 months after the operation. CONCLUSIONS: The maxillary sinus route can provide a clear vision for sectioning of the maxillary nerve. This new surgical technique has proven to be safe and effective. It provides another option for the weak elderly who are intolerant of craniotomy or patients who have contraindications for craniotomy when radiofrequency thermocoagulation (RFT) and percutaneous glycerol neurolysis (PGR) treatment is not possible.

Ablation of the sphenopalatine ganglion does not attenuate the infarct reducing effect of vagus nerve stimulation.

Electrical stimulation of the cervical vagus nerve reduces infarct size by approximately 50% after cerebral ischemia in rats. The mechanism of ischemic protection by vagus nerve stimulation (VNS) is not known. In this study, we investigated whether the infarct reducing effect of VNS was mediated by activation of the parasympathetic vasodilator fibers that originate from the sphenopalatine ganglion (SPG) and innervate the anterior cerebral circulation. We examined the effects of electrical stimulation of the cervical vagus nerve in two groups of rats: one with and one without SPG ablation. Electrical stimulation was initiated 30 min after induction of ischemia, and lasted for 1h. Measurement of infarct size 24h later revealed that the volume of ischemic damage was smaller in those animals that received VNS treatment (41.32±2.07% vs. 24.19±2.62% of the contralateral hemispheric volume, n=6 in both; p<0.05). SPG ablation did not abolish this effect; the reduction in infarct volume following VNS was 58% in SPG-damaged animals, 41% in SPG-intact animals (p>0.05). In both SPG-intact and SPG-damaged animals VNS treatment resulted in better motor outcome (p<0.05 vs. corresponding controls for both). Our findings show that VNS can protect the brain against acute ischemic injury, and that this effect is not mediated by SPG projections.

Neurochemical characterization of pterygopalatine ganglion branches in humans.

BACKGROUND: Pterygopalatine ganglion (PPG) branches, seem to be involved in the pathophysiology of facial pain. The functions of these branches, including a recently discovered orbital branch, are not completely known but could be of clinical significance. This study was designed to characterize PPG branches through immunohistochemical stain and study their anatomy, specifically the orbital branches. METHODS: In a cadaver study of four specimens, the pterygopalatine fossa (PPF) was dissected out of its bony surroundings as a tissue block. Subsequently, cryostat sectioning of these blocks was performed. In one specimen the PPF was microscopically dissected. Recently discovered neural structures were identified, dissected out of the tissue block, and cryosectioned. All cryostat sectionings were immunohistochemically stained for protein gene product (PGP) 9.5, nitric oxide synthase (NOS), and tyrosine hydroxylase (TH). RESULTS: A recently discovered neural connection between the PPG and the ophthalmic nerve could be confirmed and classified as an orbital PPG branch. The connection stained throughout for PGP 9.5 and partially stained for NOS. In other orbital branches, both NOS and TH(+) nerve fibers were found. The PPG contained NOS(+) cells. TH labeling was also found in nerve fibers running through the PPG and the vidian nerve. CONCLUSION: The recently discovered orbital PPG branch is of a mixed parasympathetic and sensory nature. In the other orbital branches, sympathetic fibers were shown as well. This knowledge may add to understanding the symptomatology and therapies of headache syndromes such as nerve block.

Effects of radiofrequency thermocoagulation of the sphenopalatine ganglion on headache and facial pain: correlation with diagnosis.

AIMS: To study the effect of radiofrequency thermocoagulation (RFT) of the sphenopalatine ganglion (SPG) on headache and facial pain conditions following critical reevaluation of the original diagnosis. METHODS: This was a retrospective study of clinical records gathered over 4 consecutive years of all 15 facial pain or headache patients who underwent RFT of the SPG at a tertiary pain clinic; diagnoses were reevaluated, after which the effect of RFT on facial pain was assessed. RESULTS: After application of new criteria for Sluder's neuralgia (SN) and strict criteria for cluster headache (CH), seven patients out of the 15 turned out to have been diagnosed correctly. Nine of the 15 patients showed considerable pain relief after RFT of the SPG. Positive results were most frequent among patients with Sluder's neuropathy, atypical facial pain, and CH. However, repeated RFT procedures were needed in most patients. CONCLUSION: Correct headache and facial pain diagnosis is vital to assess the outcome of different treatment strategies. Even in a tertiary center, headache and facial pain can be misdiagnosed. RFT of the SPG may be effective in patients with facial pain, but repeated procedures are often needed.