Improved outcome in the treatment of trigeminal neuralgia by percutaneous stereotactic rhizotomy with a new, curved tip electrode

Neuronavigation-Specific Parameters for Selective Access of Trigeminal Rootlets in Radiofrequency Lesioning: A Cadaveric Morphometric Study

BACKGROUND AND OBJECTIVE

Radiofrequency lesioning (RFL) is a safe and effective treatment for medically refractory trigeminal neuralgia. Despite gaining mainstream neurosurgical acceptance in the 1970s, the technique has remained relatively unchanged, with the majority of series using lateral fluoroscopy over neuronavigation for cannula guidance. To date, there are no studies describing neuronavigation-specific parameters to help neurosurgeons selectively target individual trigeminal rootlets. In this cadaveric study, we sought to provide a neuronavigation-specific morphometric roadmap for selective targeting of individual trigeminal rootlets.

METHODS

Embalmed cadaveric specimens were registered to cranial neuronavigation. Frontotemporal craniotomies were then performed to facilitate direct visualization of the Gasserian ganglion. A 19-gauge cannula was retrofit to a navigation probe, permitting real-time tracking. Using preplanned trajectories, the cannula was advanced through foramen ovale (FO) to the navigated posterior clival line (nPCL). A curved electrode was inserted to the nPCL and oriented inferolaterally for V3 and superomedially for V2. For V1, the cannula was advanced 5 mm distal to the nPCL and the curved electrode was reoriented inferomedially. A surgical microscope was used to determine successful contact. Morphometric data from the neuronavigation unit were recorded.

RESULTS

Twenty RFL procedures were performed (10R, 10L). Successful contact with V3, V2, and V1 was made in 95%, 90%, and 85% of attempts, respectively. Mean distances from the entry point to FO and from FO to the clival line were 7.61 cm and 1.26 cm, respectively.

CONCLUSION

In this proof-of-concept study, we found that reliable access to V1-3 could be obtained with the neuronavigation-specific algorithm described above. Neuronavigation for RFL warrants further investigation as a potential tool to improve anatomic selectivity, operative efficiency, and ultimately patient outcomes.

Percutaneous radiofrequency treatment of the gasserian ganglion for trigeminal neuralgia complicated by trochlear nerve palsy: a case report

Background

Trigeminal neuralgia (TN) has the highest incidence of disorders causing facial pain. TN is provoked by benign stimuli, like shaving, leading to severe, short-lasting pain. Patients are initially treated using antiepileptic drugs; however, multiple invasive options are available when conservative treatment proves insufficient. Percutaneous radiofrequency treatment of the trigeminal, or gasserian, ganglion (RF-G) is a procedure regularly used in refractory patients with comorbidities. RF-G involves complex needle maneuvering to perform selective radiofrequency heat treatment of the affected divisions. We present a unique case of cranial nerve 4 (CN4) paralysis after RF-G.

Case presentation

A male patient in his 60s presented with sharp left-sided facial pain and was diagnosed with TN, attributed to the maxillary and mandibular divisions. MRI showed a vascular loop of the anterior inferior cerebellar artery without interference of the trigeminal complex. The patient opted for RF-G after inadequate conservative therapy. The procedure was performed by an experienced pain physician and guided by live fluoroscopy. The patient was discharged without problems but examined the following day for double vision. Postprocedural MRI showed enhanced signaling between the trigeminal complex and the brainstem. Palsy of CN4 was identified by a neurologist, and spontaneous recovery followed 5 months after the procedure.

Conclusions

Mention of postprocedural diplopia in guidelines is brief, and the exact incidence remains unknown. Different mechanisms for cranial nerve (CN) palsy have been postulated: incorrect technique, anatomical variations, and secondary heat injury. We observed postprocedural hemorrhage and hypothesized that bleeding might be a contributing factor in injury of CNs after RF-G.

Analysis of radiofrequency lesions in egg whites in vitro produced by application of the Tew electrode for different temperatures and times

BACKGROUND

Understanding the size and shape of radiofrequency lesions is important to reduce side effects when applied to patients.

OBJECTIVES

To investigate the radiofrequency lesions produced by the application of the Tew electrode for different temperatures and times.

METHODS

The white from a fresh hen's egg was placed in a rectangular glass container and warmed to 37 °C. After immersion of the Tew electrode in the egg white, radiofrequency lesions were produced at 65 °C, 70 °C, 75 °C, 80 °C, 85 °C and 90 °C. For each temperature, photographs were taken at 10 s, 20 s, 30 s, 40 s, 50 s, 60 s, 70 s, 80 s, 90 s, 100 s, 110 s and 120 s. The size of the lesion was measured at each temperature and time. A mixed model was used to analyze the data.

RESULTS

The size of the lesion increased with increasing temperature and time. There were statistically significant differences in the size of the internal radius between the 65 °C and 70 °C groups and the 70 °C and 75 °C groups, as well as in the 70 °C and 75 °C groups in the size of the external radius and the 60 °C to 80 °C groups in the size of the distal radius. The maximum lesion size was produced at 90 °C and 120 s, and was 1.06±0.16 mm in internal radius, 0.37±0.15 mm in external radius, 0.39±0.04 mm in distal radius.

CONCLUSION

The Tew electrode produces lesions following the contour of the tip, and the internal radius is larger than the external and distal radius. The best combination of temperature and time for lesioning using the Tew electrode is 80 °C, for 60 s to 90 s.

Advances in diagnosis and treatment of trigeminal neuralgia

Various drugs and surgical procedures have been utilized for the treatment of trigeminal neuralgia (TN). Despite numerous available approaches, the results are not completely satisfying. The need for more contemporaneous drugs to control the pain attacks is a common experience. Moreover, a number of patients become drug resistant, needing a surgical procedure to treat the neuralgia. Nonetheless, pain recurrence after one or more surgical operations is also frequently seen. These facts reflect the lack of the precise understanding of the TN pathogenesis. Classically, it has been related to a neurovascular compression at the trigeminal nerve root entry-zone in the prepontine cistern. However, it has been evidenced that in the pain onset and recurrence, various neurophysiological mechanisms other than the neurovascular conflict are involved. Recently, the introduction of new magnetic resonance techniques, such as voxel-based morphometry, diffusion tensor imaging, three-dimensional time-of-flight magnetic resonance angiography, and fluid attenuated inversion recovery sequences, has provided new insight about the TN pathogenesis. Some of these new sequences have also been used to better preoperatively evidence the neurovascular conflict in the surgical planning of microvascular decompression. Moreover, the endoscopy (during microvascular decompression) and the intraoperative computed tomography with integrated neuronavigation (during percutaneous procedures) have been recently introduced in the challenging cases. In the last few years, efforts have been made in order to better define the optimal target when performing the gamma knife radiosurgery. Moreover, some authors have also evidenced that neurostimulation might represent an opportunity in TN refractory to other surgical treatments. The aim of this work was to review the recent literature about the pathogenesis, diagnosis, and medical and surgical treatments, and discuss the significant advances in all these fields.

Long-term outcomes of percutaneous radiofrequency thermocoagulation of gasserian ganglion for 2nd- and multiple-division trigeminal neuralgia

OBJECTIVES

The objective of this study was to examine the long-term outcome of percutaneous radiofrequency thermocoagulation (PRT) of the Gasserian ganglion for the 2nd division and multiple division trigeminal neuralgia (TN), compared to the isolated 3rd division TN.

METHODS

One hundred and forty-eight procedures performed in 89 patients with typical TN between April 2004 and September 2011 in a single pain center were retrospectively analyzed. Baseline characteristics of these patients, immediate outcome, duration pain-free, and complications were obtained from their medical records and questionnaires sent in June 2012. Duration pain-free was assessed by Kaplan-Meier analysis.

RESULTS

Of the 148 PRT of the Gasserian ganglion, 37 procedures were performed for isolated 2nd-division TN (V2 TN), 67 procedures were for both 2nd- and 3rd-division TN (V2 + V3 TN), and 38 procedures were for isolated 3rd-division TN (V3 TN). The remaining 6 procedures were performed for V1 + V2 TN and V1 + V2 + V3 TN. Immediate success rates of PRT for V2 TN, V2 + V3 TN, and V3 TN were 100%, 86.6%, and 100%, respectively, whereas the durations pain-free for V2 TN and V2 + V3 TN were significantly shorter than that for V3 TN (9, 12, and 36 months, respectively: P = 0.012).

CONCLUSION

For 2nd-division TN and multiple-division TN, less long-term pain relief after PRT of the Gasserian ganglion can be expected compared with that for isolated trigeminal 3rd-division neuralgia, even if immediate pain relief is achieved.

Foramen ovale puncture, lesioning accuracy, and avoiding complications: microsurgical anatomy study with clinical implications

Object

Foramen ovale (FO) puncture allows for trigeminal neuralgia treatment, FO electrode placement, and selected biopsy studies. The goals of this study were to demonstrate the anatomical basis of complications related to FO puncture, and provide anatomical landmarks for improvement of safety, selective lesioning of the trigeminal nerve (TN), and optimal placement of electrodes.

Methods

Both sides of 50 dry skulls were studied to obtain the distances from the FO to relevant cranial base references. A total of 36 sides from 18 formalin-fixed specimens were dissected for Meckel cave and TN measurements. The best radiographic projection for FO visualization was assessed in 40 skulls, and the optimal trajectory angles, insertion depths, and topographies of the lesions were evaluated in 17 specimens. In addition, the differences in postoperative pain relief after the radiofrequency procedure among different branches of the TN were statistically assessed in 49 patients to determine if there was any TN branch less efficiently targeted.

Results

Most severe complications during FO puncture are related to incorrect needle placement intracranially or extracranially. The needle should be inserted 25 mm lateral to the oral commissure, forming an approximately 45° angle with the hard palate in the lateral radiographic view, directed 20° medially in the anteroposterior view. Once the needle reaches the FO, it can be advanced by 20 mm, on average, up to the petrous ridge. If the needle/radiofrequency electrode tip remains more than 18 mm away from the midline, injury to the cavernous carotid artery is minimized. Anatomically there is less potential for complications when the needle/radiofrequency electrode is advanced no more than 2 mm away from the clival line in the lateral view, when the needle pierces the medial part of the FO toward the medial part of the trigeminal impression in the petrous ridge, and no more than 4 mm in the lateral part. The 40°/45° inferior transfacial–20° oblique radiographic projection visualized 96.2% of the FOs in dry skulls, and the remainder were not visualized in any other projection of the radiograph. Patients with V1 involvement experienced postoperative pain more frequently than did patients with V2 or V3 involvement. Anatomical targeting of V1 in specimens was more efficiently achieved by inserting the needle in the medial third of the FO; for V2 targeting, in the middle of the FO; and for V3 targeting, in the lateral third of the FO.

Conclusions

Knowledge of the extracranial and intracranial anatomical relationships of the FO is essential to understanding and avoiding complications during FO puncture. These data suggest that better radiographic visualization of the FO can improve lesioning accuracy depending on the part of the FO to be punctured. The angles and safety distances obtained may help the neurosurgeon minimize complications during FO puncture and TN lesioning.

Percutaneous controlled radiofrequency trigeminal rhizotomy for the treatment of idiopathic trigeminal neuralgia: 25-year experience with 1,600 patients

OBJECTIVE

The objective of this study was to evaluate the effectiveness of percutaneous, controlled radiofrequency trigeminal rhizotomy (RF-TR). The outcome of 1,600 patients with idiopathic trigeminal neuralgia after RF-TR was analyzed after a follow-up period of 1 to 25 years.

METHODS

A total of 1,600 patients with idiopathic trigeminal neuralgia underwent 2,138 percutaneous radiofrequency rhizotomy procedures between 1974 and 1999. Sixty-seven patients had bilateral idiopathic trigeminal neuralgia, and 36 of them were treated with bilateral RF-TR; 1,216 patients (76%) were successfully managed with a single procedure, and the remainder were treated with multiple procedures. Benzodiazepines and narcotic analgesics were used for anesthesia because patient cooperation during the procedures was essential so that the physician could create selective, controlled lesions.

RESULTS

The average follow-up time was 68.1 +/- 66.4 months (range, 12-300 mo). Acute pain relief was accomplished in 97.6% of patients. Complete pain relief was achieved at 5 years in 57.7% of the patients who underwent a single procedure. Pain relief was reported in 92% of patients with a single procedure or with multiple procedures 5 years after the first rhizotomy was performed. At 10-year follow-up, 52.3% of the patients who underwent a single procedure and 94.2% of the patients who underwent multiple procedures had experienced pain relief; at 20-year follow-up, 41 and 100% of these patients, respectively, had experienced pain relief. No mortalities occurred. After the first procedure was performed, early pain recurrence (<6 mo) was observed in 123 patients (7.7%) and late pain recurrence was observed in 278 patients (17.4%). Complications included diminished corneal reflex in 91 patients (5.7%), masseter weakness and paralysis in 66 (4.1%), dysesthesia in 16 (1 %), anesthesia dolorosa in 12 (0.8%), keratitis in 10 (0.6%), and transient paralysis of Cranial Nerves III and VI in 12 (0.8%). Permanent Cranial Nerve VI palsy was observed in two patients, cerebrospinal fluid leakage in two, carotid-cavernous fistula in one, and aseptic meningitis in one.

CONCLUSION

Percutaneous, controlled RF-TR represents a minimally invasive, low-risk technique with a high rate of efficacy. The procedure may safely be repeated if pain recurs.

Long-term outcome of percutaneous thermocoagulation for trigeminal neuralgia

A retrospective analysis of long-term efficacy of percutaneous radiofrequency thermocoagulation of the trigeminal ganglion or root for the relief of trigeminal neuralgia was carried out in our unit. From the medical records and questionnaires, outcomes of 108 procedures performed in 81 patients from January 1986 to December 1990 were obtained with a follow-up period of 6-11 years. The initial success rate was 87% and the probability of remaining pain-free 1, 2 and 11 years after the procedure was 65, 49 and 26%, respectively. Patients with typical symptoms had a better long-term efficacy than those with atypical presentations, and patients who had not undergone a previous surgical procedure also had a better outcome. There was no mortality in this series. Common adverse effects included dysaesthesia in 20 patients, corneal numbness in 12 patients and masseter weakness in three patients.

Abducens nerve palsy after radiofrequency rhizolysis for trigeminal neuralgia: case report

OBJECTIVE AND IMPORTANCE

Abducens nerve palsy is a rare and reversible complication associated with percutaneous radiofrequency trigeminal rhizolysis.

CLINICAL PRESENTATION

An 86-year-old man developed an abducens nerve palsy immediately after undergoing percutaneous radiofrequency trigeminal rhizolysis for severe trigeminal neuralgia involving all three divisions of the trigeminal nerve. The palsy resolved spontaneously after 2 months.

CONCLUSION

This case, in combination with previous reports, suggests that cases of transient sixth nerve palsy associated with percutaneous radiofrequency trigeminal rhizolysis for trigeminal neuralgia are more likely to occur in elderly patients with ophthalmic division involvement.

Comparison of surgical treatments for trigeminal neuralgia: reevaluation of radiofrequency rhizotomy

In this study, we reevaluate the results of radiofrequency rhizotomy and review the effectiveness of other surgical procedures for the treatment of trigeminal neuralgia. Five hundred patients with trigeminal neuralgia underwent radiofrequency rhizotomy at the University of Cincinnati Medical Center, Cincinnati, OH, between 1981 and 1986. Their results are compared with those of patients reported in the literature who underwent radiofrequency rhizotomy (6205 patients), glycerol rhizotomy (1217 patients), balloon compression (759 patients), microvascular decompression (MVD) (1417 patients), and partial trigeminal rhizotomy (250 patients). Comparisons were based on the following outcome parameters: technical success, pain relief and recurrence, facial numbness, dysesthesia, corneal anesthesia, keratitis, trigeminal motor dysfunction, permanent cranial nerve deficit, intracranial hemorrhage or infarction, perioperative morbidity, and perioperative mortality. We found that MVD had the lowest rate of technical success. Radiofrequency rhizotomy and MVD had the highest rates of initial pain relief and the lowest rates of pain recurrence. Glycerol rhizotomy had the highest rate of pain recurrence. Balloon compression had the highest rate of trigeminal motor dysfunction. Balloon compression and MVD had the lowest rates of corneal anesthesia or keratitis. MVD had the lowest rates of facial numbness and dysesthesia. All percutaneous procedures had similar rates of dysesthesia. Posterior fossa exploration had the highest rates of permanent cranial nerve deficit, intracranial hemorrhage or infarction, and perioperative morbidity and mortality. On the basis of our experience and a review of the literature, we conclude the following: 1) percutaneous techniques and posterior fossa exploration offer advantages and disadvantages, 2) radiofrequency rhizotomy is the procedure of choice for most patients undergoing first surgical treatments, and 3) MVD is recommended for healthy patients who have isolated pain in the first ophthalmic trigeminal division or in all three trigeminal divisions and patients who desire no sensory deficit.

A micrometric multiple electrode array for the exploration of gasserian and retrogasserian trigeminal fibers: preliminary report. Technical note

The determination of the target for percutaneous thermocoagulation of the trigeminal rootlets has been generally based on the analysis of subjective clinical verbal and motor responses as assessed by freehand displacement of an electrode active at its straight or curved distal tip. In a previous report, we demonstrated that sensory and motor trigeminal evoked potentials are of practical value when attempting to localize the position of trigeminal electrodes. This report describes the technical features of a multiple electrode array designed to provide simultaneous access to various segments along a chosen trigeminal division or divisions, correlating at each segment clinical and electrophysiological data with radiological landmarks in the individual patient. The system consists of an outer needle with four windows at a distance of 15 mm from the tip. A multiple electrode array occludes the windows with four isolated caps for stimulation and recording. After correlating clinical verbal and motor responses with sensory and motor evoked potentials at each window and inter se, a target window is selected. A thermocouple fitted with a micromanipulator allows the accurate placement of the center of the active tip at the center of the chosen window. Preliminary data from 25 patients indicate that the technique provides a reliable sequential analysis of clinical, electrophysiological, and radiological data along the explored tract.

Percutaneous procedures for trigeminal neuralgia: microcompression versus radiofrequency thermocoagulation. Personal experience

This paper reports the results achieved in the treatment of trigeminal neuralgia using two different percutaneous procedures: radiofrequency (RF) thermocoagulation (33 patients) and the new percutaneous microcompression (PMC; 74 patients) of the trigeminal ganglion. Acute pain relief was accomplished in 93.2% of the patients treated with PMC and in 81.8% of those treated with the RF method. Two years after the operation, neuralgia had recurred in 56% of the PMC patients and in 42.4% of the RF patients. The average recurrence time was 6.5 months after PMC and 18.5 months after RF. Side effects were essentially of 2 kinds: marked dysaesthesia that occurred after RF lesion in 24.2% and after PMC in 6.7% of the patients, and weakness of the masticatory muscles that was fairly common after PMC, although clinically relevant in only 1 case. The procedure has the benefit of simplicity and fewer side effects. The results obtained by using different compression times in different patients indicates that the most suitable compression time is between 4 and 6 min. When pain recurred the procedure was repeated unless the pain was in the third division, in which case an RF lesion was made. If the pain recurred a second time, RF lesions were made if the pain was in the second or third division.

Trigeminus stereoguide: an instrument for stereotactic approach through the foramen ovale and foramen jugulare

The author describes a new, fully stereotactic instrument for the percutaneous treatment of tic douloureux. The principle is to place the instrument in such a position around the patient's head that the foramen ovale lies at the midpoint for a spherical system consisting of a cylinder part and a 90 degrees arch with an electrode carrier. The foramen can then be reached from a suitable bone-free direction, either through the cheek or inframandibularly. The position of the foramen ovale is calculated from lateral and axial radiograms and defined with x, y, and z coordinates. The instrument can also be used for the percutaneous treatment of glossopharyngeal neuralgia.