Fluoroscopic exposure during percutaneous balloon compression of the Gasserian ganglion

Trigeminal Neuralgia-Step-by-Step DYNA-Computed Tomography-Assisted Balloon Compression Rhizotomy

Trigeminal nerve balloon compression (TNBC)1-3 can provide immediate therapeutic relief to patients suffering from trigeminal neuralgia. This is a particularly effective treatment option for patients who are not eligible for surgical procedures (i.e., elderly patients or patients with multiple comorbidities) or for patients who have had an insufficient response to microvascular decompression. TNBC can also be used as a bridge treatment before stereotactic radiosurgery. Use of intraoperative computed tomography-like images using a C-arm system (DYNA-CT) imaging facilitates the TNBC procedure.4,5 Three-dimensional DYNA-CT imaging with needle guidance allows for precise needle advancement and insertion through the foramen ovale. DYNA-CT enables the direct visualization and avoidance of vascular structures such as the carotid or internal maxillary arteries and results in decreased procedure times and complications. The authors present a step-by-step video demonstrating the use of intraoperative DYNA-CT needle guidance for TNBC (Video 1). A Siemens Artis Zee Biplane system is used for the procedure. A comprehensive description of all elements of the procedure is provided including balloon preparation, needle trajectory planning, needle advancement, 3-dimensional confirmation of the needle's depth and path, balloon placement, balloon inflation, and balloon removal. Tips and optimal strategies are presented. Advantages of using DYNA-CT for needle guidance include the reduction of fluoroscopy dose and fluoroscopy time. The average dose area product during conventional percutaneous balloon compression in prior studies was 1137 mGycm2, with a mean fluoroscopic time of 62 seconds.6 In our experience, the mean fluoroscopy dose is 274 mGycm2 and the total fluoroscopic time is about 45 seconds. Furthermore, during the DYNA-CT acquisition, the neurointerventional team stays outside the room during the DYNA-CT, which reduces the cumulative radiation to the operator. DYNA-CT needle guidance facilitates precise advancement of the needle into the foramen ovale and positioning of the balloon in the Meckel cave during TNBC. It is a safe and feasible technique that allows for the visualization and avoidance of important structures such as the internal carotid artery or the internal maxillary artery, resulting in decreased procedure times and complications.

Percutaneous balloon compression technique using intraoperative contrasted DynaCT for the treatment of refractory trigeminal neuralgia: initial experience

OBJECTIVE

Percutaneous balloon compression (BC) is a well-established technique that can provide immediate relief to patients suffering from trigeminal neuralgia (TN). The general procedure of BC uses fluoroscopy imaging to guide the needle through the foramen ovale (FO). The aim of this study was to describe our experience with a novel technique using intraoperative contrast-enhanced DynaCT as an adjunct for more accurate and safer guidance of the needle to the FO.

METHODS

In this study, DynaCT was used to perform BC in 20 TN cases. The three-dimensional path of the needle was pre-planned using DynaCT obtained during the administration of IV contrast. The FO was accessed in a single pass along the path pre-determined from the DynaCT images, avoiding any major arteries and veins. DynaCT was also used for confirmation of the final position of the needle prior to insertion of the balloon as well as for confirmation of the position of the balloon after inflation.

RESULTS

Intravenous contrast-enhanced DynaCT-guided percutaneous BC allowed precise advancement and positioning of the needle within the FO. It facilitated cannulation of the FO along a pre-determined path that avoided any major vascular structures. Clinical outcomes were excellent-all patients had a quick postoperative recovery, and there were no complications.

CONCLUSIONS

The advantages of the contrast-enhanced DynaCT-guided technique include a single precise needle pass and avoidance of vessel injury. Precise placement of the balloon into different aspects of the FO can target trigeminal branches more selectively and allow for a better outcome.

Novel fluoroscopic landmark to significantly facilitate the visualization of foramen ovale in treating idiopathic trigeminal neuralgia

BACKGROUND AND OBJECTIVES

Access through the foramen ovale (FO) is essential in performing trigeminal ganglion injection, glycerol rhizolysis, balloon compression, and radiofrequency thermocoagulation (RFT) to treat idiopathic trigeminal neuralgia (ITN). However, identification of the FO under fluoroscopy can be difficult and time-consuming, and thus exposes patients to increased radiation and procedure risks. Here we present the 'H-figure' as a novel fluoroscopic landmark to quickly visualize the FO.

METHODS

The H-figure landmark can be recognized as the medial border of the mandible and the lateral edge of the maxilla as the two vertical lines, and the superior line of petrous ridge of temporal bone (S-P-T line) as the horizontal line, and the FO fluoroscopic view is then optimized at the center of the H-figure immediately above the S-P-T line. We applied this landmark in a clinical cohort of 136 patients with ITN who underwent fluoroscopy-guided RFT of the trigeminal ganglion. We also compared the H-figure method with the traditional method. The primary outcome was the total number of fluoroscopic images required to visualize the FO (as a proxy of radiation exposure). Secondary measures included the procedure time required to finalize the FO view and the sensory testing voltage for paresthesia.

RESULTS

With the H-figure approach we were able to view the FO with an average of 4.2 fluoroscopic shots at an average time of 6.8 min. When compared with the non-H-figure traditional technique, the H-figure method required almost half the fluoroscopic shots in nearly half the procedure duration time, and paresthesia was evoked with half of the voltage.

CONCLUSION

The H-figure is an easy fluoroscopic landmark that can help to view the FO with less radiation and procedure time, and the needles placed with this approach can be closer to the target for the RFT treatment of patients with ITN.

Locating the foramen ovale by using molar and inter-eminence planes: a guide for percutaneous trigeminal neuralgia procedures

OBJECTIVE

The first attempt to cannulate the foramen ovale is oftentimes unsuccessful and requires subsequent reattempts, thereby increasing the risk of an adverse event and radiation exposure to the patient and surgeon. Failure in cannulation may be attributable to variation in soft-tissue-based landmarks used for needle guidance. Also, the incongruity between guiding marks on the face and bony landmarks visible on fluoroscopic images may also complicate cannulation. Therefore, the object of this study was to assess the location of the foramen ovale by way of bony landmarks, exclusive of soft-tissue guidance.

METHODS

A total of 817 foramina ovalia (411 left-sided, 406 right-sided) from cranial base images of 424 dry crania were included in the study. The centroid point of each foramen ovale was identified. A sagittal plane through the posterior-most molar (molar plane) and a coronal plane passing through the articular eminences of the temporal bones (inter-eminence plane) were superimposed on images. The distances of the planes from the centroids of the foramina were measured. Also, counts were taken to assess how often the planes and their intersections crossed the boundary of the foramen ovale.

RESULTS

The average distance between the molar plane and the centroid of the foramen was 1.53 ± 1.24 mm (mean ± SD). The average distance between the inter-eminence plane and the centroid was 1.69 ± 1.49 mm. The molar and inter-eminence planes crossed through the foramen ovale boundary 83.7% (684/817) and 81.6% (667/817) of the time, respectively. The molar and inter-eminence planes passed through the boundary of the foramen together 73.5% (302/411) of the time. The molar and inter-eminence planes intersected within the boundary of the foramen half of the time (49.4%; 404/817).

CONCLUSIONS

The results of this study provide a novel means of identifying the location of the foramen ovale. Unlike the soft-tissue landmarks used in the many variations of the route of Härtel, the bony landmarks identified in this study can be palpated, marked on the face, appreciated fluoroscopically, and do not require any measurement from soft-tissue structures. Utilizing the molar and inter-eminence planes as cannulation guides will improve the approach to the foramen ovale and decrease the amount of radiation exposure to both the patient and surgeon.

Orientation of the Foramen Ovale: An Anatomic Study With Neurosurgical Considerations

Unsuccessful cannulation of the foramen ovale (FO) continues to occur with both fluoroscopic technique and technique using computed tomography paired with navigational technology. Despite advances in stereotactic neurosurgical imaging and technique, anatomic variation of the FO occasionally prevents successful cannulation. Morphometric study of the FO has been limited to length, width, and area parameters; therefore, this report analyzed the orientation of the FO. A total of 139 crania (235 foramina ovalae) were photographed and assessed digitally by ImageJ software (NIH). Foramina were fit with a best fit ellipse. For orientation, the midsagittal plane was located by bisecting the basilar process of the occiput; the coronal plane was identified as perpendicular to the midsagittal plane. The angles between the major axis of the best fit ellipse of the FO and the midsagittal and coronal planes were measured. The angle formed between the major axis of the best fit ellipse of the FO and the coronal plane averaged 35.43° ± 9.74° (mean ± SD) on the left and 36.47° ± 7.60° on the right. The angle formed between the major axis of the best fit ellipse of the FO and the sagittal plane averaged 54.57° ± 9.74° on the left and 53.53° ± 7.60° on the right. No significant difference was found between FO orientation among the sexes. Understanding the orientation of the FO may aid in stereotactic neurosurgical planning and successful cannulation of the FO.

Optimal duration of percutaneous microballoon compression for treatment of trigeminal nerve injury

Percutaneous microballoon compression of the trigeminal ganglion is a brand new operative technique for the treatment of trigeminal neuralgia. However, it is unclear how the procedure mediates pain relief, and there are no standardized criteria, such as compression pressure, compression time or balloon shape, for the procedure. In this study, percutaneous microballoon compression was performed on the rabbit trigeminal ganglion at a mean inflation pressure of 1,005 ± 150 mmHg for 2 or 5 minutes. At 1, 7 and 14 days after percutaneous microballoon compression, the large-diameter myelinated nerves displayed axonal swelling, rupture and demyelination under the electron microscope. Fragmentation of myelin and formation of digestion chambers were more evident after 5 minutes of compression. Image analyzer results showed that the diameter of trigeminal ganglion cells remained unaltered after compression. These experimental findings indicate that a 2-minute period of compression can suppress pain transduction. Immunohistochemical staining revealed that vascular endothelial growth factor expression in the ganglion cells and axons was significantly increased 7 days after trigeminal ganglion compression, however, the changes were similar after 2-minute compression and 5-minute compression. The upregulated expression of vascular endothelial growth factor in the ganglion cells after percutaneous microballoon compression can promote the repair of the injured nerve. These findings suggest that long-term compression is ideal for patients with recurrent trigeminal neuralgia.

Minimizing technical failure of percutaneous balloon compression for trigeminal neuralgia using neuronavigation

Objective. Percutaneous balloon compression (PBC) is an effective and safe management for medically refractory trigeminal neuralgia; however, technical failure to cannulate the foramen ovale (FO) using only fluoroscopy is a significant problem in some cases. In this paper, we suggest the use of intraoperative navigation, in cases of reoperation due to prior technical failure to cannulate the FO under fluoroscopy. Methods. A total of 174 patients underwent PBC for TN since 2003. In 9 cases the penetration of the FO was not accomplished. Five of those patients were reoperated on for PBC using navigation from March 2012 to September 2012.

SURGICAL TECHNIQUE

preoperatively, a head Computed Tomography (CT) scan is performed and the acquired images are imported into the navigation system. Intraoperatively, a small reference frame is strapped firmly to the patient's forehead, the CT images are registered, and cannulation is performed under the guidance of the navigation system. Results. In all patients, the operation overall was completed successfully. Moreover, all patients reported complete pain relief immediately postoperatively and no complications were recorded overall. Conclusions. We suggest the use of neuronavigation in cases of technical failure of PBC. That technique involves technology with significant advantages helping the successful cannulation of the FO and seems more efficient and safer.

Percutaneous microballoon compression for trigeminal neuralgia using Dyna-CT

Percutaneous microballoon compression (PMC) is a well-established technique for treatment of trigeminal neuralgia (TN). However, direct puncture of the foramen ovale (FO) is sometimes difficult and there have been well-reported complications from cannulating the FO. We describe our experiences in using Dyna-CT for cannulating the FO and determining balloon position and volume. Dyna-CT was used to perform image reconstruction in 21 cases. The optimal working projection was generated and further fluoroscopic data were used to determine the needle's relationship to the foramen during puncture. Furthermore, the balloon position and three-dimensional shape were verified by Dyna-CT during balloon compression. The balloon volume and puncture angle were further calculated. Patients' prognosis was further discussed. Dyna-CT allowed quick, safe, and easy cannulation of the FO. It provided three-dimensional images which were more elaborate than the classic 'pear-shaped' images for determining correct positioning in 21 cases. The volume of the flattened balloon ranged from 568.2 mm(3) to 891.4 mm(3) with an average of 775.9 mm(3). The angle of introducing the cannula ranged from 15.17°-35.48° rotation to the midline with an average of 26.24° and 38.47°-51.89° angulation to the Reid line with an average of 46.09°. All the patients were pain free after PMC. Four patients had resolvable masseter weakness and fine touch loss. There was no recurrence of TN during follow-up. Dyna-CT demonstrated three advantages in assisting PMC. Firstly, the FO can be better visualized irrespective of the patient's position. Secondly, needle correction or insertion can be performed much more easily because of the direct fluoroscopic control. Thirdly, the needle position, balloon position, balloon configuration and the volume of the inflated balloon are more reliably determined. The use of dyna-CT provided an assisted method to PMC with a low incidence of complications and good prognosis.