Etiology and Management of Recurrent and Persistent Hemifacial Spasm-A Single-Center Experience.

BACKGROUND AND OBJECTIVES: Despite a 90% success rate, microvascular decompression occasionally fails to resolve hemifacial spasm (HFS), necessitating revision surgery. We investigated recurrent cases to identify underlying causes. METHODS: We evaluated patients at our institution who underwent revision microvascular decompression because of recurrent or persistent HFS, assessing recurrence causes, decompression techniques, complications, and outcomes. Data considered included demographics, preoperative symptoms, disease duration, offending vessel, and magnetic resonance findings. Surgical notes and intraoperative videos were reviewed, and telephone interviews were conducted for recent outcomes. RESULTS: Out of our ongoing series of 493 patients, 43 patients (8.7%) required revision surgery with a patient cohort of 33 females and 10 males. The average symptom duration was 10 years. The median time between primary and revision surgery was 14 months. Thirteen patients (30.2%) underwent initial surgery elsewhere. Adhesions of Teflon pledgets to the facial nerve were the primary cause of nonresolution in 23 patients (53.5%), while in 13 (30.2%), a missed vascular compression was identified. Sixteen patients (37.2%) had sufficient decompression by removing the conflicting pledgets. During 10 revisions (23.3%), additional Teflon pledgets were necessary. After a median follow-up of 67 months after revision surgery, 27 patients (62.8%) reported complete spasm resolution. Six patients (14.0%) had a good outcome with over 90% reduction of their spasms, 3 patients (7.0%) stated a fair outcome (50% improvement), while 7 patients (16.3%) had no improvement. CONCLUSION: According to our results, adhesions of Teflon to the facial nerve may cause HFS recurrence. Therefore, whenever possible, Teflon should be placed without nerve contact between the brainstem and the offending vessel. Using a sling or bridge technique seems to be beneficial because it leaves the facial nerve completely free. Persistent symptoms often result from missed offending vessels in the pontomedullary sulcus indicating the benefit of endoscopic inspection of this area with an endoscope.

Endoscope-Assisted Microsurgery for Posterior Fossa Skull Base Meningioma Surgery: Technique and Results.

BACKGROUND AND OBJECTIVES: Surgery of posterior fossa meningiomas is extremely challenging even for experienced skull base surgeons because of the close proximity to cranial nerves and tight spaces. Endoscope-assisted surgery for posterior fossa meningiomas can enable a high degree of tumor resection even when using small approaches. This study describes the advantage of endoscope-assisted microneurosurgery in resection of posterior fossa skull base meningiomas and the clinical outcome. METHODS: All endoscope-assisted surgeries for resection of posterior fossa meningiomas performed between 2002 and 2016 in our department were retrospectively analyzed. For data acquisition, the patient files were used. Tumor size and extent of resection were evaluated on pre- and postoperative magnetic resonance imaging. The value of endoscope assistance was assessed according to the intraoperative videos and the surgical notes. Complications and long-term outcomes were evaluated. RESULTS: We identified 39 female and 10 male patients. The mean age of the patients at the time of surgery was 55 years, ranging from 25 to 78 years. The mean follow-up was 93.8 months. A total of 41% of the tumors were large to giant. The retrosigmoid approach was used in most patients (45). A gross total resection could be achieved in 38 patients (78%). In 11 patients (22%), a near total resection was performed. In 27 patients (55%), a hidden residual tumor, which could not been visualized with the operating microscope, was identified with the endoscope. In 6 patients (22.2%), the internal auditory canal was visualized, in 9 patients (33.3%), the Meckel's cave was visualized, and in 5 patients (18.5%), both were visualized under endoscope assistance. In 26 of those patients (96.3%), the residual tumor was resected under endoscopic view. CONCLUSION: Endoscope-assisted surgery for posterior fossa skull base meningiomas enables a high degree of tumor resection, avoids more invasive skull base approaches, and reduces the amount of cerebellar retraction.

Preemptive strategies and lessons learned from complications encountered with microvascular decompression for hemifacial spasm.

OBJECTIVE: Microvascular decompression (MVD) is the only curative treatment modality for hemifacial spasm (HFS). Although generally considered to be safe, this surgical procedure is surrounded by many risks and possible complications. The authors present the spectrum of complications that they met in their case series, the possible causes, and the strategies recommended to minimize them. METHODS: The authors reviewed a prospectively maintained database for MVDs performed from 2005 until 2021 and extracted relevant data including patient demographics, offending vessel(s), operative technique, outcome, and different complications. Descriptive statistics with uni- and multivariable analyses for the factors that may influence the seventh, eighth, and lower cranial nerves were performed. RESULTS: Data from 420 patients were obtained. Three hundred seventeen of 344 patients (92.2%) with a minimum follow-up of 12 months had a favorable outcome. The mean follow-up (standard deviation) was 51.3 ± 38.7 months. Immediate complications reached 18.8% (79/420). Complications persisted in only 7.14% of patients (30/420) including persistent hearing deficits (5.95%) and residual facial palsy (0.95%). Temporary complications included CSF leakage (3.10%), lower cranial nerve deficits (3.57%), meningitis (0.71%), and brainstem ischemia (0.24%). One patient died because of herpes encephalitis. Statistical analyses showed that the immediate postoperative disappearance of spasms and male gender are correlated with postoperative facial palsy, whereas combined vessel compressions involving the vertebral artery (VA) and anterior inferior cerebellar artery can predict postoperative hearing deterioration. VA compressions could predict postoperative lower cranial nerve deficits. CONCLUSIONS: MVD is safe and effective for treating HFS with a low rate of permanent morbidity. Proper patient positioning, sharp arachnoid dissection, and endoscopic visualization under facial and auditory neurophysiological monitoring are the key points to minimize the rate of complications in MVD for HFS.

Biomechanical comparison of two different compression screws for the treatment of odontoid fractures in human dens axis specimen.

BACKGROUND: Lag screw osteosynthesis for odontoid fractures has a high rate of pseudoarthrosis, especially in elderly patients. Besides biomechanical properties of the different screw types, insufficient fragment compression or unnoticed screw stripping may be the main causing factors for this adverse event. The aim of the study was to compare two screws in clinical use with different design principles in terms of compression force and stability against screw stripping. METHODS: Twelve human cadaveric C2 vertebral bodies were considered. Bone density was determined. The specimens were matched according to bone density and randomly assigned to two experimental groups. An odontoid fracture was induced, which were fixed either with a 3.5 mm standard compression screw or with a 5 mm sleeve nut screw. Both screws are certified for the treatment of odontoid fractures. The bone samples were fixed in a measuring device. The screwdriver was driven mechanically. The tests were analyzed for peak interfragmentary compression and screw-in torque with a frequency of 20 Hz. FINDINGS: The maximum fragment compression was significantly higher with screw with sleeve nut at 346.13(SD ±72.35) N compared with classic compression screw at 162.68(SD ±114.13) N (p = 0.025). Screw stripping occurred significantly earlier in classic compression screw at 255.5(SD ±192.0)° rotation after reaching maximum compression than in screw with sleeve nut at 1005.2(SD ±341.1)° (p = 0.0039). INTERPRETATION: Screw with sleeve nut achieves greater fragment compression and is more robust to screw stripping compared to classic compression screw. Whether the better biomechanical properties lead to a reduction of pseudoarthrosis has to be proven in clinical studies.

Endoscope-assisted microsurgical resection of a third ventricular immature teratoma.

BACKGROUND: Reaching a tumor within the third ventricle is challenging, and planning an accessible trajectory is crucial without injuring the surrounding structures. We report a 5-year-old boy presented with headache and a seizure where sequential MRI brain studies in a short time period revealed a rapid growing immature teratoma within the third ventricle with hydrocephalic changes. Several management procedures were performed for CSF diversion and medical treatment of the tumor with chemotherapy and stem cell therapy. The tumor was rapidly growing, and surgical excision was decided. Total resection was achieved via endoscope-assisted microsurgical transcallosal approach. Seven years after surgery, the patient experienced no recurrence of the tumor with a favorable clinical condition. CONCLUSION: We report a rare case of posterior third ventricular immature teratoma where the endoscope-assisted microsurgical technique was implemented with favorable long-term postoperative outcome.

The value of intraoperative indocyanine green angiography in microvascular decompression for hemifacial spasm to avoid brainstem ischemia.

PURPOSE: Despite being rarely reported, ischemic insults resulting from compromising small brainstem perforators following microvascular decompression (MVD) remain a potential devastating complication. To avoid this complication, we have been using indocyanine green (ICG) angiography intraoperatively to check the flow within the small brainstem perforators. We aim to evaluate the safety and usefulness of ICG videoangiography in MVD. METHODS: We extracted retrospective data of patients who received ICG videoangiography from our prospectively maintained database for microvascular decompression. We noted relevant data including demographics, offending vessels, operative technique, outcome, and complications. RESULTS: Out of the 438 patients, 15 patients with a mean age (SD) of 53 ± 10.5 years underwent intraoperative ICG angiography. Male:female was 1:1.14. The mean disease duration prior to surgery was 7.7 ± 5.3 years. The mean follow-up (SD) was 50.7 ± 42.0 months. In 14 patients, the offending vessel was an artery, and in one patient, a vein. Intraoperative readjustment of the Teflon pledget or sling was required in 20% (3/15) of the cases. No patient had any sort of brainstem ischemia. Eighty percent of the patients (12/15) experienced complete resolution of the spasms. 86.7% (13/15) of the patients reported a satisfactory outcome with marked improvement of the spasms. Three patients experienced slight hearing affection after surgery, which improved in two patients later. There was no facial or lower cranial nerve affection. CONCLUSION: Intraoperative ICG is a safe tool for evaluating the flow within the brain stem perforators and avoiding brainstem ischemia in MVD for hemifacial spasm.

Long-term quality of life after ETV or ETV with consecutive VP shunt placement in hydrocephalic pediatric patients.

PURPOSE: Endoscopic third ventriculostomy (ETV) and ventriculoperitoneal shunting are well-established treatments of obstructive hydrocephalus (HCP) in adult and pediatric patients. However, there is a lack of data with regard to the quality of life (QoL) of these patients during long-term follow-up METHODS: Inclusion criteria were pediatric patients with endoscopic treatment of hydrocephalus at the University Medicine Greifswald between 1993 and 2016. Patients older than 14 years at present were assessed with the Short Form-12 (SF-12) questionnaire. Patients younger than 14 years of age were assessed with the KINDL-R questionnaire that was completed by their parents. Patients' values were compared with the scores of a corresponding age-matched group of the healthy population and with patients who received later shunt treatment. Information about comorbidities, current symptoms, and educational level were gained by an additional part. Comparative analysis between patients with ETV success and failure (defined as shunt implantation after ETV) was performed. RESULTS: A total of 107 patients (53 m, 54f) were included. Fifty-seven/107 patients (53.3%) were considered as ETV success. Mean age at ETV was 6.9 ± 5.9 years. Fifty-four statements of 89 patients that are still alive were gained (response rate 63%). Of these, 49 questionnaires were complete and evaluable (23 m, 26f; mean age 19.8 ± 10.0 years with an average follow-up period of 13.7 ± 7.2 years). Twenty-six/49 patients (53.1%) are considered ETV success. No statistically significant differences could be obtained between patients with ETV success and ETV failure. Patients older 14 years show QoL within normal range, patients younger than 14 years show significantly lower result regarding their environment of peers and social contacts. Patients younger than 6 months at the time of ETV and patients with posthemorrhagic HCP show significantly lower physical QoL. Gait disturbance, fatigue, and seizures are associated with a lower QoL, and educational level is lower than in the normal population. CONCLUSIONS: Patients who underwent ETV in childhood do not have a lower health-related QoL in general. Subsequent insertions of ventriculoperitoneal (vp) shunts do not lower QoL. Certain subgroups of the patients show lower results compared to the healthy population.

Pineal cysts without hydrocephalus: microsurgical resection via an infratentorial-supracerebellar approach-surgical strategies, complications, and their avoidance.

Indications for surgery of pineal cysts without ventriculomegaly are still under debate. In view of the limited data for pineal cyst resection in the absence of hydrocephalus, and the potential risk of this approach, we have analyzed our patient cohort focusing on strategies to avoid complications according to our experience in a series of 73 pineal cyst patients. From 2003 to 2015, we reviewed our database retrospectively for all patients operated on a pineal cyst. Furthermore, we prospectively collected patients from 2016 to 2020. In summary, 73 patients with a pineal cyst were treated surgically between 2003 and 2020. All patients were operated on via a microscopic supracerebellar-infratentorial (SCIT) approach. The mean follow-up period was 26.6 months (range: 6-139 months). Seventy-three patients underwent surgery for a pineal cyst. An absence of enlarged ventricles was documented in 62 patients (51 female, 11 male, mean age 28.1 (range 4-59) years). Main presenting symptoms included headache, visual disturbances, dizziness/vertigo, nausea/emesis, and sleep disturbances. Complete cyst resection was achieved in 59/62 patients. Fifty-five of 62 (89%) patients improved after surgery with good or even excellent results according to the Chicago Chiari Outcome Scale, with complete or partial resolution of the leading symptoms. Pineal cysts resection might be an indication in certain patients for surgery even in the absence of ventriculomegaly. The high percentage of postoperative resolution of quality-of-life impairing symptoms in our series seems to justify surgery. Preoperatively, other causes of the leading symptoms have to be excluded.

Value of Endoscopic Visualization During the Sling-Transposition Technique for Microvascular Decompression of the Facial Nerve in a Case with Hemifacial Spasm.

Endoscopic visualization during microvascular decompression for hemifacial spasm enables better identification of compression areas along the facial nerve, which is especially important in cases with complex compression and enlarged vessels obscuring the compression site. A 40-year-old man presented with a 10-year history of left hemifacial spasm. Magnetic resonance imaging showed a deep compression site with multiple vessels. Within the narrow space, the compression area was clearly visualized using an angled endoscope. Arterial transposition was performed using a polytetrafluoroethylene (Teflon) sling, which was fixed to the nearby dura using an aneurysm clip. Decompression was visually confirmed using the angled endoscope. The patient was free of spasms directly after surgery with no further complications and no recurrence of spasm during 6-month follow-up (Video 1).

Purely venous compression in trigeminal neuralgia-can we predict the outcome of surgery.

PURPOSE: Controversies regarding venous compression and trigeminal neuralgia (TN) still exist. The study demonstrates our experience for microvascular decompression (MVD) in TN caused by purely venous compression. The goal was to identify prognostic anatomical or surgical factors that may influence the outcome. METHODS: Between 2004 and 2020, 49 patients were operated with purely venous compression. Average age was 58.4 years. Mean history of TN was 7.8 years. Microsurgical procedures included transposition or separation of the vein, coagulation, and division. Several features have been analyzed with respect to BNI scores. RESULTS: Evaluation on discharge revealed a complete pain relief in 39 (80%), partial improvement in 7 (14%), and no benefit in 3 (6%) patients. Facial hypesthesia was reported by 14 (28.6%) patients. Mean follow-up (FU) was 42.1 months. BNI pain intensity score on FU revealed 71.4% excellent to very good scores (score 1: 32 (65.3%); 2: 3 (6.1%)). BNI facial numbness score 2 could be detected in 13 patients (26.5%) during FU. There was no statistical relationship between immediate pain improvement or BNI pain intensity score on FU with respect to surgical procedure, size of trigeminal cistern, type of venous compression, venous caliber, trigeminal nerve indentation, or neurovascular adherence. BNI facial numbness score was dependent on type of venous compression (p < 0.05). CONCLUSION: We did not find typical anatomical features that could either predict or influence the outcome regarding pain improvement or resolution in any form. Neither classic microvascular decompression (interposition/transposition) nor sacrificing the offending vein made any difference in outcome.

A multivariable prediction model for recovery patterns and time course of symptoms improvement in hemifacial spasm following microvascular decompression.

BACKGROUND: Microvascular decompression (MVD) success rates exceed 90% in hemifacial spasm (HFS). However, postoperative recovery patterns and durations are variable. OBJECTIVE: We aim to study factors that might influence the postoperative patterns and duration needed until final recovery. METHOD: Only patients following de-novo MVD with a minimum follow-up of 6 months were included. Overall trend of recovery was modeled. Patients were grouped according to recognizable clinical recovery patterns. Uni- and multivariable analyses were used to identify the factors affecting allocation to the identified patterns and time needed to final recovery. RESULTS: A total of 323 (92.6%) patients had > 90% symptom improvement, and 269 (77.1%) patients had complete resolution at the last follow-up. The overall trend of recovery showed steep remission within the first 6 months, followed by relapse peaking around 8 months with a second remission ~ 16 months. Five main recovery patterns were identified. Pattern analysis showed that evident proximal indentation of the facial nerve at root exit zone (REZ), males and facial palsy are associated with earlier recovery at multivariable and univariable levels. anterior inferior cerebellar artery (AICA), AICA/vertebral artery compressions and shorter disease durations are related to immediate resolution of the symptoms only on the univariable level. Time analysis showed that proximal indentation (vs. distal indentation), males and facial palsy witnessed significantly earlier recoveries. CONCLUSION: Our main finding is that in contrast to peripheral indentation, proximal indentation of the facial nerve at REZ is associated with earlier recovery. Postoperative facial palsy and AICA compressions are associated with earlier recoveries. We recommend a minimum of 1 year before evaluating the final outcome of MVD for HFS.

Long-term outcome and quality of life after CNS cavernoma resection: eloquent vs. non-eloquent areas.

The aim of this study is to analyze the long-term quality of life after surgery of cavernoma. A monocentric retrospective study was conducted on 69 patients with cavernoma treated microsurgically between 2000 and 2016. The eloquence was adopted from Spetzler-Martin definition. A most recent follow-up was elicited between 2017 and 2019, in which the quality of life (QoL) was evaluated with the Short Form-12 questionnaire (SF12). Forty-one lesions were in eloquent group (EG), 22 in non-eloquent group (NEG), 3 in orbit, and 3 in the spinal cord. Postoperative worsening of the modified Rankin scale (mRS) occurred in 19.5% of cases in EG versus 4.5% in NEG. After a mean follow-up of 6.5 years (SD 4.6), the neurological status was better or unchanged compared to baseline in 85.4% of EG and 100% of NEG. Regarding QoL assessment of 44 patients (EG n = 27, NEG n = 14) attended the last follow-up. Patients after eloquent cavernoma resection reported a non-inferior QoL in most SF12 domains (except for physical role) compared to NEG. However, they reported general health perception inferior to norms, which was affected by the limited physical and emotional roles. At a late follow-up, the surgical morbidity was transient in the NEG and mostly recovered in the EG. The QoL comparison between eloquent and non-eloquent cavernomas created interesting and new data after prolonged follow-up. These results add value for decision-making as well as patient counseling for future encountered cases. Preoperative evaluation of QoL is recommended for future studies to assess QoL dynamics.

Outcome of Endoscope-Assisted Microvascular Decompression in Patients With Hemifacial Spasm Caused by Severe Indentation of the Brain Stem at the Pontomedullary Sulcus by the Posterior Inferior Cerebellar Artery.

BACKGROUND: Microvascular decompression (MVD) is the most effective treatment option for hemifacial spasm (HFS). However, deeply located forms of compression would require proper identification to allow for adequate decompression. OBJECTIVE: To describe the usefulness of endoscopic visualization in one of the most challenging compression patterns in HFS, where the posterior inferior cerebellar artery (PICA) loop is severely indenting the brain stem at the proximal root exit zone of facial nerve along the pontomedullary sulcus. METHODS: Radiological and operative data were checked for all patients in whom severe indentation of the brainstem by PICA at pontomedullary sulcus was recorded and endoscope-assisted MVD was performed. Clinical correlation and outcome were analyzed. RESULTS: A total of 58 patients with HFS were identified with radiological and surgical evidence proving brainstem indentation at the VII transitional zone. In 31 patients, PICA was the offending vessel to the facial nerve. In 3 patients, the PICA loop was mobilized under visualization of a 45° endoscope. A total of 31 patients had a mean follow-up duration of 52.1 mo. The mean duration between start of complaints and surgery was 7.2 yr. In the last follow-up, all patients had remarkable spasm improvement. A total of 5 patients had more than 90% disappearance of spasms and 26 patients experienced spasm-free outcome. CONCLUSION: Although severe indentation of brain stem implies morphological damage, outcome after MVD is excellent. A 45° endoscope is extremely helpful to identify compression down at the pontomedullary sulcus. Deeply located compression site can easily be missed with microscopic inspection alone.

Quality of life and olfactory function after suprasellar craniopharyngioma surgery-a single-center experience comparing transcranial and endoscopic endonasal approaches.

The endoscopic endonasal approach to suprasellar craniopharyngiomas has become popular as alternative to transcranial approaches. However, the literature lacks data regarding quality of life and olfactory function. The assessment of the long-term quality of life and olfactory function of all patients harboring a suprasellar craniopharyngioma who underwent surgery in our department has been done. Patient characteristics and perioperative data were gathered in a prospectively maintained database. At the last follow-up visit, the olfactory function and the quality of life (ASBQ, SNOT-22) as well as visual and pituitary function were assessed. Thirteen and 17 patients underwent surgery via a transcranial (T) and endonasal (E) route, respectively. No differences were seen in ASBQ, SNOT-22, and olfactory function between T and E, but in E were more full-time worker and less obesity. CSF leaks occurred in 15% of T and 29% of E (p = 0.43). Patients from group E had a superior visual outcome which was most pronounced in the visual field. The degree of new anterior and posterior pituitary gland deficiency after surgery and in the follow-up was lower in group E. The general and sinonasal quality of life and the olfactory function are equal in E and T. E is associated with a superior visual outcome, lower rates of diabetes insipidus, and lower rates of obesity, but has a higher risk for postoperative CSF leaks.

Biomechanical comparison of three different compression screws for treatment of odontoid fractures evaluation of a new screw design.

BACKGROUND: Lag screw osteosynthesis in odontoid fractures shows a high rate of pseudarthrosis. Biomechanical properties may play a role with insufficient fragment compression or unnoticed screw stripping. A biomechanical comparison of different constructed lag-screws was carried out and the biomechanical properties determined. METHODS: Two identical compression screws with different pilot holes (1.25 and 2.5 mm), a double-threaded screw and one sleeve-nut-screw were tested on artificial bone (Sawbone, densities 10-30pcf). Fragment compression and torque were continuously measured using thin-film force sensors (Flexiforce A201, Tekscan) and torque sensors (PCE-TM 80, PCE GmbH). FINDINGS: The lowest compression reached the double-threaded screw. Compression and sleeve-nut-screw achieved 214-298% and 325-546%, respectively, of the compression force of double-threaded-screw, depending on the test material. The pilot hole optimization led to a significant improvement in compression only in the densest test material. Screw stripping took place significantly later with increasing density of the test material on all screws. In compression screws this was done at a screw rotation of 180-270°, in sleeve nut screw at 270-720° and in double-threaded screws at 300-600° after reaching the maximum compression. INTERPRETATION: Double-threaded screw is robust against screw stripping, but achieves only low fragment compression. The classic compression screws achieve better compression, but are sensitive to screw stripping. Sleeve-nut screw is superior in compression and as robust as double-threaded screw against screw stripping. Whether the better biomechanical properties lead to a reduction in pseudarthrosis must be proven in clinical trials.

Pineal Cyst without Hydrocephalus: Clinical Presentation and Postoperative Clinical Course After Infratentorial Supracerebellar Resection.

BACKGROUND: Surgical indications for patients with pineal cysts are controversial. There are absolute indications such as hydrocephalus or tectal compression; otherwise, it is difficult to decide whether surgery would be beneficial when symptoms are not distinct. OBJECTIVE: We tried to clarify the indications and clinical course of patients after resection of pineal cysts without ventriculomegaly. METHODS: We reviewed our database for all patients operated on for pineal cyst without ventriculomegaly from 2003 to 2018. We studied the presenting symptoms, cyst size, surgical approach, extent of resection, and clinical and radiologic follow-up. Follow-up ranged from 3 months to 14 years (mean 3.74 years). RESULTS: Forty-three patients underwent surgery for pineal cyst in absence of ventriculomegaly; 36 female patients, 7 male patients, mean age 25.63 years (±10.62 years, range 4-52 years). Presenting symptoms included headache (41/43), nausea and vomiting (31/43), dizziness (19/43), visual disturbances (10/43), and sleep disturbances (8/43). Mean cyst size was 15.7 mm (±4.9 mm, range 9-27 mm). In total, 41 of 43 patients reported a good outcome, represented by a Chicago Chiari Outcome Scale score of 11 or greater and only 2 of 43 patients reported a bad outcome, defined by Chicago Chiari Outcome Scale score of 10 or less. CONCLUSIONS: We suggest that pineal cysts without ventriculomegaly are an indication for surgery when patients present with headache and/or visual disturbances and other causes have been excluded. Resolution of symptoms and quality of life in our cohort may denote a good indication for resection. However, we must admit that there is still no evidence to recommend this technique as a treatment of headache in these patients.