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.

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.

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.

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.

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.

Relationship between volume of pterygopalatine fossa and block anesthesia of maxillary nerve: a pilot study / Relación entre el volumen de la fosa pterigopalatina y la anestesia troncular del nervio maxilar: un estudio piloto

Block anesthesia of maxillary nerve 9BAMN) is achieved by depositing anesthesia through greater palatine canal into the pterygopalatine fossa. Authors differ in the amount of anesthesia to be administered and the rate of complications (diplopia and hematomas), Coronado et al., (2008), measured the size of the pterygopalatine fossa finding an average of 1.2 ml, suggesting that amount of anesthesia for BAMN. The aim of this study is to compare the effectiveness of low doses of 1.2 ml (LD)versus traditional dose of 1.8 m. (TD) of anesthesia for BAMN and its adverse effects. A quasi experimental exploratory clinical study was performed involving 82 patients where the anesthetic technique was suitable for tooth extraction procedure; patients were randomized in LD and TD groups, 2 percent lidocaine with 1:50.000 epinephrine was used. Demographic (sex and age), clinical (tooth for extraction and anesthetic dose) as well as anatomical variables (upper facial and cranial index) were recorded. The anesthetic success (AS) was defined as the possibility to perform the tooth extraction with no pain or minimal pain as measured by visual analogue scale (VAS). For statistical analysis chi-square and t test (p <0.05) were used. The results show that the pain and AS were 2.93 and 61.67 percent in LD group and 3.09 and 59.09 percent in TD group respectively, there were 6 cases of diplopia with no significant statistical difference between groups.

El bloqueo troncular del nervio maxilar (BTNM) se logra depositando anestesia vía canal palatino mayor en la fosa pterigopalatina. Los autores difieren en la cantidad de anestesia a depositar y la tasa de complicaciones asociadas (diplopía y hematomas). Coronado et al. (2008) midió el volumen de la fosa pterigopalatina encontrando un promedio de 1,2ml, sugiriendo dicha cantidad de anestesia para el BTNM. El objetivo del presente trabajo es comparar la eficacia de dosis bajas de 1,2ml (DB) versus dosis tradicional de 1,8ml (DT) de anestesia para el BTNM y sus efectos adversos. Se realizó un estudio clínico cuasiexperimental de carácter exploratorio, participaron 82 pacientes donde la técnica anestésica estaba indicada para un procedimiento de exodoncia, los que fueron aleatorizados en los grupos DB y DT, administrándoles lidocaína al 2 por ciento con 1:50.000 de epinefrina. Se registraron variables demográficas (sexo y edad), clínicas (pieza a extraer y dosis administrada) y anatómicas (índices facial superior y craneal). El éxito anestésico (EA) se definió como la posibilidad de realizar la exodoncia con nulo o mínimo dolor, medido con escala visual análoga (EVA). En el análisis estadístico se utilizaron los tests de chi cuadrado y t de student (p<0,05). Los resultados muestran que el dolor y el EA en el grupo DB fueron de 2,93 y 61,67 por ciento y en el DT de 3,09 y 59,09 por ciento respectivamente, hubo 6 casos de diplopía sin diferencias estadísticamente significativas entre ambos grupos.

Endoscopic transsphenoidal vidian neurectomy.

The purpose of this report is to describe a novel technique for endoscopic vidian neurectomy (EVN) based on preoperative computed tomography (CT) classification of the vidian canal (VC), and to present anatomical and surgical findings from an initial series. Retrospective study, consisting of medical chart review and patient interviews, of all preoperative CT-guided EVN procedures was performed from 2006 to 2010 at a tertiary-care medical center. A total of 89 patients with intractable rhinorrhea (77 males and 12 females, mean age 29 years, age range 16-57 years) underwent bilateral EVN. Configuration of the VC was classified into three types based on preoperative CT findings. The technique for surgical access of each of these configurations is presented. The most common configuration of the VC was type 2 (47%). A wide, direct, and safe exposure of the vidian nerve was achieved in all cases. 84 of 89 patients completed the questionnaires regarding the postoperative improvement in quality of life. Follow-up ranged from 2 to 42 months, with an average of 19.6 months. 77 of 84 (91.7%) patients were satisfied with their surgical result. Two patients underwent revision ETSVN due to relapsed symptoms. With the help of a preoperative CT scan of the paranasal sinuses, the vidian nerve can be identified precisely via an endoscopic intrasphenoidal or transsphenoidal approach, which provides an easy and reliable way to perform vidian neurectomy.

Endoscopic vidian neurectomy: the value of preoperative computed tomographic guidance.

OBJECTIVE: To explore the vidian nerve anatomy by endoscopy and paranasal sinus computed tomography (CT) to elucidate the appropriate surgical approach based on preoperative CT images. DESIGN: Retrospective analysis. SETTING: Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan, Republic of China. PATIENTS: Sixty-seven patients underwent 106 endoscopic vidian neurectomies between January 9, 2006, and June 30, 2009. MAIN OUTCOME MEASURES: Paranasal sinus CT had been performed in all patients 2 weeks before surgery. Preoperative surgical planning was based on CT images, which were compared with intraoperative endoscopic findings. Two endoscopic approaches were used for vidian nerve transection, and the success rates were recorded for each. RESULTS: The transsphenoidal approach was successful on 42 sides (39.6%), while the transnasal approach was successful on 91 sides (85.8%). Success rates for the transsphenoidal approach were 0.0%, 72.1% (31 of 43 sides), and 84.6% (11 of 13 sides) for canal corpus types 1, 2, and 3, respectively. Success rates for the transsphenoidal approach were 50.0% (28 of 56 sides), 51.9% (14 of 27 sides), 0.0%, and 0.0% for canal floor relationship types 1, 2, 3, and 4, respectively. The transsphenoidal approach was successful only in patients without an embedded canal and with a canal floor relationship type 1 or type 2. Presence of the septum and continuation of the canal bony structure also influenced the choice of surgical approach. CONCLUSIONS: The vidian nerve can be precisely identified and microinvasively transected using endoscopy. Preoperative CT images delineate the vidian canal and enhance preoperative surgical planning.