Fully endoscopic vascular decompression of the facial nerve for hemifacial spasm

Applying the Full Endoscopic Keyhole Technique to CPA Lesions: A Single-Center Study

In recent years, endoscopy has become an increasingly common tool used during neurosurgical procedures. However, its application in treating cerebellopontine angle (CPA) lesions has not progressed as rapidly. In this study, the authors present their initial experience with surgically treating CPA lesions using a fully endoscopic keyhole retrosigmoid approach. They conducted a retrospective analysis of clinical data from patients who underwent endoscopic keyhole CPA surgery at their center between May 2017 and April 2022. They provide a comprehensive explanation of this method and an overview of the strategies that have been developed to achieve better clinical outcomes. The study included 107 patients, consisting of 10 cases of vestibular schwannoma, 21 cases of epidermoid cyst, 32 cases of trigeminal neuralgia, and 44 cases of hemifacial spasm. The authors analyzed the clinicodemographic details of the patients. Among the 31 tumor cases, gross total resection was achieved in 25 patients (80.6%), while near-total resection was performed in 6 patients (19.4%). In patients with trigeminal neuralgia, facial pain resolved in 31 out of 32 patients (96.9%). Similarly, facial convulsions disappeared or were relieved in all 44 patients (100%) with hemifacial spasms after the operation. Postoperative complications included facial nerve paresis (n=9, 8.4%), with improvement observed in 6 cases during follow-up, transient facial hypoesthesia (n=3, 2.8%), cerebrospinal fluid rhinorrhea (n=3, 2.8%), transient abducens paresis (n=1, 0.9%), and postoperative hemorrhage (n=1, 0.9%). Endoscopy provides improved deep illumination and, combined with close-up observation, enhances the visualization of structures within the CPA region. The fully endoscopic keyhole technique is a safe and effective method for managing CPA lesions.

Endoscopic Microvascular Decompression

Microvascular decompression is a widely accepted surgical treatment for compressive cranial nerve pathologies such as trigeminal neuralgia, hemifacial spasm, glossopharyngeal neuralgia, and other craniofacial pain syndromes. Endoscopy has risen as a safe and effective minimally invasive tool to optimize microvascular decompression. Endoscopy offers improved visualization, minimizes retraction, and allows for smaller surgical openings compared to traditional microscopic approaches. There are several reports of improved neuralgia outcomes and reduced post-operative complications after endoscopic microvascular decompression. In skilled surgical hands, endoscopy is an excellent option for microvascular decompression as stand-alone tool or adjunct to the microscope. An overview of the history, operative considerations, and techniques is provided in this chapter.

Microvascular decompression using a fully transcranial neuroendoscopic approach

OBJECTIVE

To evaluate the effectiveness and safety of microvascular decompression (MVD) using a fully transcranial neuroendoscopic approach.

METHODS

Thirty-one patients who underwent MVD using a fully transcranial neuroendoscopic approach in our department between May 2016 and September 2019 were retrospectively reviewed.

RESULTS

All patients successfully underwent MVD, and immediate pain relief was achieved in all 17 cases of trigeminal neuralgia (TGH) and 3 cases of glossopharyngeal neuralgia (GPN). Hemifacial spasm (HFS) was completely resolved in all 11 patients. No mortality or permanent complication was seen.

CONCLUSIONS

The endoscope is a useful tool for confirming vascular conflict identified by the microscope and is helpful in detecting the vessel responsible for neuralgia without retracting the brain and nerves. MVD using a fully transcranial neuroendoscopic approach is an effective and safe alternative to endoscopic-assisted MVD and traditional MVD.

Supratentorial Acute Subdural Hematoma During Fully Endoscopic Microvascular Decompression Surgery for Hemifacial Spasm

The endoscope has been widely used in microvascular decompression (MVD), which is the best curative treatment for hemifacial spasm. Supratentorial subdural hematoma (SDH) is rarely happened in MVD. The authors report 2 cases of SDH during full endoscopic MVD. The origin of bleeding is not confirmed during the operation. Rapid and excessive drainage of cerebrospinal fluid and the operation position may result the rupture of bridging veins, which result in the occurrence of SDH. However, there is no clear evidence to explain the clinical symptoms.

Case report: Fully endoscopic microvascular decompression for glossopharyngeal neuralgia

With the advances in endoscopic technology, endoscopy is widely used in many neurosurgical procedures, such as microvascular decompression, which is an effective method to treat glossopharyngeal neuralgia, trigeminal neuralgia, and facial spasm. The purpose of this study was to determine the efficacy of fully endoscopic microvascular decompression in the treatment of glossopharyngeal neuralgia. We managed a patient with glossopharyngeal neuralgia in our department, whose main clinical manifestation was recurrent left ear and facial pain for 3 years. The patient underwent a fully endoscopic microvascular decompression. The pain in the left ear and face was significantly relieved postoperatively, and there was no recurrence at the 6-month follow-up evaluation. We describe a case of glossopharyngeal neuralgia that was successfully treated by fully endoscopic microvascular decompression, which showed that endoscopy has advantages in microvascular decompression, and fully endoscopic microvascular decompression is an effective method for glossopharyngeal neuralgia.

Technical Assessment of Microvascular Decompression for Trigeminal Neuralgia Using a 3-Dimensional Exoscope: A Case Series

BACKGROUND

Detailed anatomic visualization of the root entry zone of the trigeminal nerve is crucial to successfully perform microvascular decompression surgery (MVD) in patients with trigeminal neuralgia.

OBJECTIVE

To determine advantages and disadvantages using a 3-dimensional (3D) exoscope for MVD surgery.

METHODS

A 4K 3D exoscope (ORBEYE) was used by a single surgical team for MVD in a retrospective case series of 8 patients with trigeminal neuralgia in a tertiary center. Clinical and surgical data were collected, and advantages/disadvantages of using the exoscope for MVD were recorded after each surgery. Descriptive statistics were used to summarize the data.

RESULTS

Adequate MVD of the trigeminal nerve root was possible in all patients by exclusively using the exoscope. It offered bright visualization of the cerebellopontine angle and the root entry zone of the trigeminal nerve that was comparable with a binocular operating microscope. The greatest advantages of the exoscope included good optical quality, the pronounced depth of field of the image for all observers, and its superior surgeon ergonomics. Disadvantages were revealed with overexposure at deep surgical sites and the lack of endoscope integration. In 6 patients, facial pain improved significantly after surgery (Barrow Neurological Institute pain intensity score I in 5 and III in 1 patient), whereas it did not in 2 patients (Barrow Neurological Institute score IV and V). No complications occurred.

CONCLUSION

Utilization of a 3D exoscope for MVD is a safe and feasible procedure. Surgeons benefit from better ergonomics, excellent image quality, and an improved experience for observers.

Simultaneous Endoscopic and Microscopic Visualization in Microvascular Decompression for Hemifacial Spasm

BACKGROUND

Hemifacial spasm (HFS) is a socially limiting condition leading to decreased quality of life that can be treated with microvascular decompression (MVD). Endoscopy has been described as an adjunct to traditional microscopy for MVD, although the best visualization technique is debated.

OBJECTIVE

To review the current literature on use of endoscopy in MVD for HFS and to describe the simultaneous microscopic and endoscopic visualization technique along with a video illustration.

METHODS

Patients who underwent MVD for HFS were retrospectively reviewed from January 2011 to December 2019. The first set of patients in the series were done using traditional endoscopic assisted visualization, followed by a change in technique in the subsequent patients using the simultaneous endoscopic technique. The surgical technique is described as well as illustrated with a video.

RESULTS

In total, 21 patients underwent 24 MVDs to treat HFS. The simultaneous endoscopic/microscopic technique was used in 48% of cases for visualization. All but one patient had resolution of their symptoms immediately after the procedure. In total, 7 patients had recurrence of HFS, with 4 (17%) resolving spontaneously and 3 (13%) ultimately undergoing redo MVD. Postoperatively 7 patients (29%) had transient complications that all resolved completely. There was no significant difference between the traditional alternating microscopic and endoscopic technique with the simultaneous endoscopic microscopic technique.

CONCLUSION

Endoscopic assistance during MVD for HFS is beneficial and may be streamlined by using the simultaneous microscope and endoscope visualization technique.

Endoscope-assisted microsurgical retrosigmoid approach to the lateral posterior fossa: Cadaveric model and a review of literature

Background:

The advancement of endoscopic techniques in the past decade has improved the surgical management of cerebellopontine angle (CPA) tumors. Endoscope-assisted microsurgery improves the ability to evaluate the extent of resection, achieve safe tumor resection and reduce the risk of surgery-related morbidity.

Methods:

In this study, we used a cadaveric model to demonstrate a step by step endoscope-assisted microsurgery of the retrosigmoid approach to the lateral posterior fossa.

Results:

Retrosigmoid craniotomies were performed on four latex-injected cadaver heads (eight CPAs). Microsurgical exposures were performed to identify neurovascular structures in each segment. 0° and 30° rigid endoscope lenses were subsequently introduced into each corridor and views were compared in this manner. The endoscopic images were compared with the standard microscopic views to determine the degree of visualization with each technique. In each case, better visualization was provided by both the 0° and 30° endoscope lenses. Endoscopic views frequently clarified neurovascular relationships in obscured anatomic regions.

Conclusion:

Endoscope-assisted microsurgery could allow better visualization of various regions of the posterior fossa. Surgical planning for posterior fossa lesions should include consideration of this combined approach.

Fully endoscopic versus microscopic vascular decompression for hemifacial spasm: a retrospective cohort study

INTRODUCTION

Microvascular decompression (MVD) is the preferred surgical method for hemifacial spasm (HFS). The purpose of this study was to analyze the effectiveness and safety of fully endoscopic MVD for HFS relative to microscopic MVD.

MATERIAL AND METHODS

The retrospective study was conducted on HFS patients who underwent microscopic or fully endoscopic MVD from January 2018 to March 2019. All patients were treated at a single institution and by a single surgeon. Patients were divided into two groups based on the surgical method, and clinical data were then compared between groups.

RESULTS

A total of 116 patients, including 54 cases who received fully endoscopic MVD (E group) and 62 cases who received microscopic MVD (M group), were included in this study. Follow-up efficacy did not differ significantly between groups, with total effective rates of 88.9% in the E group and 90.3% in the M group. When postoperative complications were compared individually, there were no statistically significant differences between the two groups; however, the E group had a higher total incidence of complications than the M group (48.1% vs. 29.0%, P = 0.034).

CONCLUSION

Although both fully endoscopic and microscopic MVD for HFS achieved good efficacy, the former method had a higher total incidence of complications. Based on the results of this study, there is no evidence that a microscope can be replaced by a full endoscope in MVD for HFS.

Fully endoscopic microvascular decompression of the hemifacial spasm: our experience

PURPOSE

Microvascular decompression (MVD) surgery has been accepted as a potentially curative method for hemifacial spasm (HFS). The primary cause of failure of MVD is incomplete decompression of the offending vessel due to inadequate visualization. This study is aimed at evaluating the benefit of endoscopic visualization and the value of fully endoscopic MVD.

METHODS

From March 2016 to March 2018, 45 HFS patients underwent fully endoscopic MVD in our department. From opening the dura to preparing to close, the assistant held the endoscope and the surgeon operated. Abnormal muscle response (AMR) and brainstem auditory evoked potentials (BAEP) were monitored. For every patient, the offending vessel was transposed or interposed and achieved complete decompression. AMR was used to evaluate the adequacy of decompression at the end of the surgery. The intra-operative findings and postoperative outcomes and complications were analyzed.

RESULTS

Immediately after surgeries, 39 patients (86.7%) achieved excellent result; 2 cases (4.4%) had good result. So the postoperative effective rate was 91.1% (41/45). During 12-36 month follow-up, the outcomes were excellent in 42 cases (93.3%) and good in 2 cases (4.4%), and the effective rate reached to 97.8% (44/45). No recurrence was noted. The postoperative complications were found in 2 patients (4.4%). One patient (2.2%) showed delayed facial palsy on the tenth day but was fully recovered 1 month later. Intracranial infection was noticed in 1 patient (2.2%) and was cured by using intravenous antibiotics for 2 weeks. There was no hearing impairment, hoarseness, or other complications.

CONCLUSIONS

Fully endoscopic MVD is both safe and effective in the treatment of HFS. Electrophysiological monitoring is helpful to gain a good result and reduce hearing impairment.

Minimally Invasive Endoscopic Retrosigmoid Approach to the Cerebellopontine Angle Using a Novel Surgical Instrument: A Cadaveric Study

OBJECTIVES

In this study, we aimed to describe how endoscopes show the neural and vascular structures at the cerebellopontine angle (CPA) through a minimal craniotomy in a well-described anatomic point in the retrosigmoid region and at the same time, evaluate the endoscopic anatomic exposure and maneuverability. We planned to use the new surgical instrument (endoscope cannula), which we designed on fresh frozen cadavers to simulate a real surgical procedure.

MATERIALS AND METHODS

The surgical procedure was planned to be performed on 20 sides of 10 fresh cadaver heads. The distance between the asterion and mastoid process was determined, and the midpoint was then marked. From this midpoint, a craniotomy 2 cm in size was posteriorly made. The endoscope cannula together with 0° or 30° endoscopes was inserted to capture the panoramic views of the neurovascular structures in CPA. Endoscopic anatomic exposure and maneuverability were evaluated using 0° and 30° endoscopes with/without the endoscope cannula.

RESULTS

The surgeon could easily use both hands during the surgical simulation, and maneuverability was seen to increase in CPA with the use of the endoscope cannula.

CONCLUSION

The surgeon can work actively with both hands when the endoscopes and the endoscope cannula are used together. We believe that owing to this, the surgeon's maneuverability would increase and a more effective minimally invasive endoscopic retrosigmoid surgery would ensue.

Endoscopically Assisted Targeted Keyhole Retrosigmoid Approaches for Microvascular Decompression: Quantitative Anatomic Study

OBJECTIVE

We describe and quantitatively assess minimally invasive keyhole retrosigmoid approaches targeted to the upper, middle, and lower cranial nerve (CN) complexes of the cerebellopontine angle (CPA).

METHODS

Anatomic dissections were performed on 10 sides of 5 fixed, silicone-injected cadaver heads. Surgical views through various trajectories were assessed in endoscopic videos and 3-dimensional (3D) interactive virtual reality microscope views. Surgical freedom and angles of attack to the proximal and distal areas of CN complexes of the CPA were compared among upper and lower keyholes and conventional retrosigmoid craniotomy using neuronavigation.

RESULTS

Compared with keyholes, the conventional approach had superior surgical freedom to most areas except for the distal CN V, the root of CN VII, and the root of CN IX, where differences were not significant. The conventional retrosigmoid approach provided a larger horizontal angle of attack than either the upper or lower keyholes for all selected areas; however, the vertical angles of attack were not different. Splitting the petrosal fissure resulted in a significant increase in the vertical angle of attack to the root zones of CNs V and VII but not to the distal areas of these nerves or CN IX. Illustrative cases of endoscope-assisted keyhole retrosigmoid approaches for the treatment of trigeminal neuralgia, hemifacial spasm, and glossopharyngeal neuralgia are presented.

CONCLUSIONS

Targeted keyhole retrosigmoid approaches require detailed understanding of the 3D anatomy of the CPA to create appropriate locations of corridors, including skin incisions and keyholes. Endoscope assistance complements the standard microsurgical technique by maximizing the visualization and identification of the delicate neurovascular structures.

Endoscope-assisted decompression of facial nerve for treatment of hemifacial spasm

Microvascular decompression has become the sole method for a curative treatment of primary hemifacial spasm. Finding the responsible conflicting artery is not always easy as its location can be deeply situated within the cerebellopontine/medullary fissure at the facial root exit zone. Sole or additional offending vessel(s) may be at the meatus of the internal auditory canal (5% of the cases). Identifying the compressive vessel(s) and performing decompression is in most cases possible without cerebellar retraction by classical microsurgical techniques. However, in a number of patients the neurovascular conflict may be hidden in spite of the direct illumination of the operative microscope. Therefore, assistance by endoscopy can be useful and contribute as a minimally invasive approach. The author reports his own experience in a series of 553 patients operated on over the past three decades. A total of 93.6% had complete relief of their spasm (11% after repeated surgery). Relief was delayed in 20.8% of these patients. Recurrence was rare (0.3%). There was no mortality and morbidity was low: deafness occurred in 0.6%. There was no permanent postoperative facial palsy. CSF leakage amounted to 1% in the last period of surgery. In conclusion, the author advocates combining the use of both the endoscopy for exploration and the microscope for decompression.

The Multiscope Technique for Microvascular Decompression

BACKGROUND

Endoscopic surgery has rapidly become widespread in neurosurgery in recent years. Endoscopy can offer close and panoramic surgical views with fine illumination, even in the deep intracranial area. However, it also has the following serious drawback: an intracranial blind area between the field lens of the endoscope and the site of the dural opening. This blind area cannot be viewed on the endoscopic monitor, and several surgical complications, including accidental intracranial neurovascular structural injury, can occur in this area. In this article, we report a new multiscope surgical technique that can compensate for this serious disadvantage of endoscopic surgery.

METHODS

In the multiscope technique, endoscopic and exoscopic systems are used simultaneously with 2 monitors. Microvascular decompression (MVD) is performed fully endoscopically using an exoscope that compensates for the intracranial blind area of the endoscopic view. Two high-definition monitors for the endoscope and exoscope are placed side-by-side in front of the primary surgeon.

RESULTS

Two patients with hemifacial spasm were treated by endoscopic MVD with the multiscope technique. In these procedures, fine surgical views were obtained by both the endoscope and exoscope. Two monitors were placed side-by-side in front of the surgeon; as a result, the physician could easily view them simultaneously during the operation. No surgery-related complications occurred.

CONCLUSIONS

The multiscope technique can facilitate the performance of safer neuroendoscopic surgery than conventional endoscopic surgery. This technique can also be adopted in other skull base surgeries, in which the importance of endoscopy is growing.

Fully endoscopic microvascular decompression for trigeminal neuralgia: technique review and early outcomes

OBJECT

Fully endoscopicmicrovascular decompression (E-MVD) of the trigeminal nerve was initially described more than 1 decade ago, but has not yet gained wide acceptance. The authors present the experience of their first 47 consecutive E-MVDs for trigeminal neuralgia (TN).

METHODS

All surgeries were performed by a single surgeon (J.Y.K.L.) at the Pennsylvania Hospital at the University of Pennsylvania. Patients prospectively completed pain scales before and after surgery by using the Brief Pain Inventory-Facial outcomes tool. All patients were called on the telephone, and the same outcome tool was administered without reference to their preoperative pain status.

RESULTS

Forty-seven patients (17 men) were identified and enrolled. Forty (85%) had Burchiel Type 1 TN. Vascular compression was observed at surgery in 42 patients (89%). No surgery was aborted or converted to microscope. One patient suffered permanent hearing loss, for a permanent neurological morbidity rate of 2%. Overall improvement in pain outcomes was excellent, with a median maximum pain intensity preoperatively of 10 and postoperatively of 0 (p< 0.0001). The mean interference with global function scores were 6.2 preoperatively and reduced to 1.0 at last follow-up (p < 0.0001). The mean interference with facial function was 7.3 preoperatively and reduced to 1.2 at last follow-up (p < 0.0001). The mean follow-up period after surgery was 15 ± 8 months.

CONCLUSIONS

In experienced hands, E-MVD offers superb visualization and illumination and is both safe and effective, at least in the short term. Further longer-term study is needed to compare E-MVD to traditional microscopic MVD.

Endoscopic Resection of Vestibular Schwannomas

Objective To report our results and the technical details of fully endoscopic resection of vestibular schwannomas. Design Prospective observational study. Setting A single academic institution involving neurosurgery and neurotology. Participants Twelve consecutive patients who underwent fully endoscopic resection of a vestibular schwannoma. Main Outcome Measures Hearing preservation, based on the American Association of Otolaryngology-Head and Neck Surgeons (AAO-HNS) score as well as the Gardener and Robertson Modified Hearing Classification (GR). Facial nerve preservation based on the House-Brackmann (HB) score. Results All patients successfully underwent gross total resection. Facial nerve preservation rate was 92% with 11 of 12 patients retaining an HB score of 1/6 postoperatively. Hearing preservation rate was 67% with 8 of 12 patients maintaining a stable AAO-HNS grade and GR score at follow-up. Mean tumor size was 1.5 cm (range: 1-2 cm). No patients experienced postoperative cerebrospinal fluid leak, infection, or cranial nerve palsy for a complication rate of 0%. Mean operative time was 261.6 minutes with an estimated blood loss of 56.3 mL and average length of hospital stay of 3.6 days. Conclusion A purely endoscopic approach is a safe and effective option for hearing preservation surgery for vestibular schwannomas in appropriately selected patients.

Endoscope-assisted retrosigmoid keyhole approach for cerebellopontine angle: cadaveric study

CONCLUSION

A 20 mm hole made backwards from the midpoint of the asterion to the mastoid process is suitable for a retrosigmoid keyhole approach with the aid of an endoscope. The endoscope-assisted retrosigmoid keyhole approach can be considered an effective and safe method for removal of vestibular schwannoma.

OBJECTIVE

To investigate the feasibility of the endoscope-assisted retrosigmoid keyhole approach for exposing the cerebellopontine angle (CPA) and internal auditory canal (IAC).

METHODS

With the aid of an endoscope, we simulated surgical procedures in 30 sides of 15 formalin-fixed cadaver heads.

RESULTS

(1) For 24 (80%) sides, the midpoint of the top notch to the mastoid process was in the anterior edge of the sigmoid sinus; for 27 sides (90%) the midpoint of the asterion to the mastoid process was in the posterior edge of the sigmoid sinus. (2) The IAC and CPA were exposed by the retrosigmoid keyhole approach with the aid of the endoscope.

Comparison of microscopic and endoscopic approaches to the cerebellopontine angle

OBJECTIVE

To examine the efficacy of the endoscope as an adjunct to the operating microscope in defining the surgical anatomy of the cerebellopontine angle (CPA).

METHODS

The surgical anatomy of the CPA was examined in cadaveric CPAs through a retrosigmoid approach. The upper, middle, and lower neurovascular complexes and the individual segments of the cerebellar arteries in the CPA were examined with the surgical microscope and 0° and 45° rigid endoscopes.

RESULTS

The microscope provided satisfactory views of the posterior surface of the neural and vascular structures in the central part of the CPA cistern. The endoscope provided superior views of the nerves' junction with the brainstem, their dural exit, and their vascular relationships. The endoscope also provided superior views of the individual segments of the cerebellar arteries.

CONCLUSION

The combination of endoscopic and microsurgical techniques aids in achieving optimal exposure in CPA surgery.

Endoscope-assisted neurovascular decompression of the trigeminal nerve: a cadaveric study

Endoscopes are increasingly used to examine cranial nerves in microvascular decompression (MVD) operations. The superior petrosal vein (SPV) is often purposely sacrificed to gain adequate exposure to the trigeminal nerve (TN) during MVD. Recently, the importance of preserving the SPV has been emphasized due to potential complications associated with its sacrifice. Our focus is to study the ability to operate on the TN with preservation of the SPV by using endoscope-assisted microsurgery. We studied both cerebellopontine angles in seven cadaveric heads which vascular system had been injected with colored silicon material. MVD procedures were simulated using the operative microscope (Moeller-Wedel, Cologne, Germany) and two fixed-angled (0°and 30°) rigid endoscopes (Aesculap, PA, USA). To compare the practical advantages of microscopic MVD (MMVD) and endoscope-assisted MVD (EAMVD), we divided the approaches into four subcategories (microscopic without and with SPV sacrifice and endoscope-assisted without and with SPV sacrifice) and compared the maneuverability associated with each category using a numerical grading system. EAMVD scored significantly better than MMVD both without and with cutting of the SPV (p < 0.001). Only in MMVD did cutting of the SPV improve the maneuverability especially in the superior quadrant of the nerve (p = 0.012). Based on the proposed scoring system, use of the endoscope in an assisted mode facilitates visualization and mobilization of the vascular loop associated with the TN without need to sacrifice the SPV. Sacrifice of the SVP may help maneuverability in the superior quadrant of the nerve in MMVD.

The endoscopic approach to vestibular schwannomas and posterolateral skull base pathology

This article provides an overview of the technical considerations of endoscopy of the posterolateral skull base and cerebellopontine angle (CPA). Specific areas of focus are on the instrumentation requirements for neuroendoscopy of the CPA; the learning curve associated with this technique; and a complete description of the surgical techniques necessary to perform the procedure, along with outcomes and results. The article provides a general overview of the endoscopic approach to the CPA. For a variety of pathologies, the emphasis is on performing this technique for acoustic tumors and hearing preservation. Insights as to how the author's practice evolved in its use of neuroendoscopic procedures are provided.

Review and update of involuntary facial movement disorders presenting in the ophthalmological setting

We review the existing literature on the involuntary facial movement disorders-benign essential blepharospasm, apraxia of eyelid opening, hemifacial spasm, and aberrant facial nerve regeneration. The etiology of idiopathic blepharospasm, a disorder of the central nervous system, and hemifacial spasm, a condition involving the facial nerve of the peripheral nervous system, is markedly different. We discuss established methods of managing patients and highlight new approaches.

Endoscopic endonasal transclival approach and retrosigmoid approach to the clival and petroclival regions

OBJECTIVE

The removal of clival lesions, mainly those located intradurally and with a limited lateral extension, may be challenging because of the lack of a surgical corridor that would allow exposure of the entire lesion surface. In this anatomic study, we explored the clival/petroclival area and the cerebellopontine angle via both the endonasal and retrosigmoid endoscopic routes, aiming to describe the respective degree of exposure and visual limitations.

METHODS

Twelve fresh cadaver heads were positioned to simulate a semisitting position, thus enabling the use of both endonasal and retrosigmoid routes, which were explored using a 4-mm rigid endoscope as the sole visualizing tool.

RESULTS

The comparison of the 2 endoscopic surgical views (endonasal and retrosigmoid) allowed us to define 3 subregions over the clival area (cranial, middle, and caudal levels) when explored via the endonasal route. The definition of these subregions was based on the identification of some anatomic landmarks (the internal carotid artery from the lacerum to the intradural segment, the abducens nerve, and the hypoglossal canal) that limit the bone opening via the endonasal route and the natural well-established corridors via the retrosigmoid route.

CONCLUSION

Different endoscopic surgical corridors can be delineated with the endonasal transclival and retrosigmoid approaches to the clival/petroclival area. Some relevant neurovascular structures may limit the extension of the approach and the view via both routes. The combination of the 2 approaches may improve the visualization in this challenging area.

What is new in the era of focal dystonia treatment? Botulinum injections and more

PURPOSE OF REVIEW

The treatment options for the management of dystonias continue to evolve and improve. Clinical outcomes, however, are not predictably consistent using a single treatment regimen in all patients.

RECENT FINDINGS

Botulinum toxin is still considered the best treatment option for the treatment of focal dystonias: blepharospasm, hemifacial spasm, and apraxia of eyelid opening. New findings indicate that physicians may be a little more aggressive with the dosage when the disease progresses. A new formulation of botulinum toxin has been produced that includes no proteins and may address the immunoresistance that can occur with prolonged use. Additional systemic medications may be helpful as adjuncts only in selected cases. Improved surgical techniques are now more successful and cause fewer complications. Therefore, many refractory cases are now offered a surgical approach alone or in combination with botulinum toxin.

SUMMARY

There have been recent therapeutic developments in the treatment of ocular dystonias.