How to cite this article: Sandoval-Balanzario MA, Álvarez-Vázquez L, Santos-Franco JA. Invasive management of trigeminal neuralgia. 8 years experience. Rev Med Inst Mex Seguro Soc. 2015;53 Supl 1:S80-7.
Received: October 22nd 2014
Accepted: March 6th 2015
Miguel Sandoval-Balanzario,a Leonardo Álvarez-Vázquez,a Jorge Arturo Santos-Francoa
aServicio de Neurocirugía, Hospital de Especialidades, Centro Médico Nacional La Raza, Distrito Federal, México.
Communication with: Leonardo Álvarez-Vázquez
Telephone: (55) 5724 5900; extensión 23204
Background: Trigeminal neuralgia (TN) is characterized by stereotyped repetitive, unilateral pain, referred as an electric shock, triggered by the stimulation of the rami of the trigeminy nerve. It presents more frequently in women. The aim is to know the efficacy of surgical treatment of TN against pain by means of microvascular decompressive technics (MDT) and balloon percutaneous microcompression (BPM).
Methods: A retrospective study was performed from January 2005 to January 2013, including 73 patients treated for TN. Sixty patients from group 1 (82 %) were treated with MDT, and 13 from group 2 with BPM. We evaluated the presence of pain in patients during the immediate postoperative period, and at 1, 3 and 5 years.
Results: 55 female patients and 18 male patients were included. The mean age of presentation for TN was 55 years. In group 1 there was pain remission in the immediate postoperative period in 95 % of the cases, in 92 % at one year, 91 % at 3 years and 88 % at 5 years; in group 2 in 85 %, 84 %, 84 % and 70 %, respectively. There were no lethal complications in 6.5 % in group 1 and in 28 % in group 2.
Conclusions; The two therapeutic procedures reduced pain of TN in a long term in most patients. Our results show high and perdurable resolution of the pain with negligible morbimortality.
Keywords: Trigeminal neuralgia; Trigeminal; Microvascular decompression
Trigeminal neuralgia (TN), also known as tic douloureux, is a stereotypical, repetitive, and paroxysmal shooting pain. It can be felt in one or more divisions of the trigeminal nerve, usually briefly, with repeated bursts every few seconds, and can be caused by activities of speaking, swallowing, touching one’s face, or brushing one’s teeth; as a result, hygiene activities and even eating are often avoided.1,2 Pain is usually unilateral and in few cases is bilateral. Two types of pain are described:
The incidence of TN is reported in the international literature at 4-5 cases per 100,000 inhabitants, with a mean age at presentation of 50 years.1,2 Less than 15% of patients are under 50 years, and the pediatric population is rarely affected, being less than 1.5% of cases.3
The right side is affected more than the left side, in a ratio of 3:2 respectively. It usually predominates in women with a ratio of 2:1.4
A retrospective study was made of TN cases treated between January 2005 and January 2013 in the Servicio de Neurocirugía of the Centro Médico Nacional La Raza. Clinical and imaging data and microsurgical videos were collected from each patient. All patients with secondary TN were excluded. The procedures used were microvascular decompression (MVD), and percutaneous balloon microcompression (PBM). The latter was used in patients who refused surgery, who had a serious concomitant pathology, and those over 70 years. Clinical follow-up of patients was done at 1, 3, and 5 years.
Brief description of techniques
Microvascular decompression (MVD) (Figure 1): We used the asterional craniectomy, which involves placing the patient lying three-quarters prone or supine with a bolster under the ipsilateral shoulder at the pain site and the head turned to the contralateral side, with skeletal fixation. The incision is paramedian, passing over the asterion, then making a circular craniotomy, approximately 2.5 cm x 2.5 cm, with rostral limits at the sigmoid sinus and dorsal limits at the transverse sinus. After opening the dura, we proceed to the microsurgical depletion of the pontocerebellar recess, always under microscopic view, and locate the cranial nerve V, its path is seen and it is released from the arachnoid flanges, and its relation with neighboring vessels is identified. We must remember that the manipulation of the nerve, as delicate as it is, can lead to significant autonomic changes, such as bradycardia and even asystole. The most common finding is a flow loop of the superior cerebellar artery compressing the nerve, in which case one should gently intersperse damp Teflon fibers. In cases without neurovascular compression, or if this is minimal or not apparent, we can make a neuropraxia, consisting of a gentle compression of the nerve.5-9
Figure 1 Microsurgical image of MVD. A: One can see the trigeminal nerve (V) that is contacted and displaced by the superior cerebellar artery (SCA). B: By means of a microdissector (D) the artery is separated from the nerve and the trigeminal clearly corrects its direction. C: Moment in which a Teflon fragment is placed between the artery and the nerve.
Percutaneous balloon microcompression (PBM) (Figure 2): This is performed in the operating room under general anesthesia. The patient is placed supine with the head extended. A trocar No. 14 with mandrel is introduced to the foramen ovale under fluoroscopic vision and X-rays are taken with Caldwell and Waters lateral projection to confirm the precise location. The mandrel is removed and sometimes cerebrospinal fluid (CSF) is obtained, which is not recommended, and immediately a Fogarty catheter size 4 with its stylet is inserted, noting certain resistance, the stylet is removed and using a syringe contrast medium is instilled, gradually inflating the balloon to its capacity. At this step new radiographies must be taken where a typical “pear-shaped” morphology will be seen. Compression is maintained for one minute, then the balloon is deflated and inflated again. The deflated catheter is removed and subsequently the trocar. Once the procedure is finished, one must compress the puncture site for several minutes to prevent hematoma. The patient must remain under surveillance for at least 24 hours.10-12
Figure 2 Treatment by means of PBM. A: Marking of points to be considered in a patient’s face. One point at 3 cm rostral to the external auditory conduit (arrow) and another in the lower eyelid at level of the mid-pupillary line point towards the situation of the foramen ovale, while a point 2.5 to 3 cm lateral to the corner of the lips indicates the place of puncture (hollow arrow). B: The second and third fingers of the surgeon’s hand enter the mouth of the patient and are placed below the ipsilateral pterygoids apophysis (dotted arrow). This way they puncture (hollow arrow) and direct the trocar towards the posterior-lateral portion of the foramen ovale, always under fluoroscopy. C: 4F Fogarty catheter is introduced towards the foramen ovale under fluoroscopy and is progressively inflated until the balloon takes on a cinched shape, like a pear (arrow).
73 patients were included, 55 cases (75%) were female and 18 were male. The mean age was 55 years, ranging from 23-80 years. Patients were divided into two groups: Group 1 underwent MVD, and Group 2 was treated with PBM.
|Table I Microvascular decompression|
|Distribution by sex|
|Age of presentation (years)|
|Type of neuralgia||n||%|
|Trigeminal branches affected||n|
|V2, V3 right||36|
|V2, V3 left||18|
|V1, V2 right||3|
|Superior cerebellar artery||35|
|Anterior-inferior cerebellar artery||9|
|No evidence of compression||8|
|Cerebrospinal fluid fistula||1|
|Table II Percutaneous balloon compression|
|Type of Neuralgia||Type 1||Type 2|
|Cases||9 (69%)||4 (31%)|
|Trigeminal branches affected||Cases|
|V2, V3 right||10 (77%)|
|V2, V3 left||3 (23%)|
|Hematoma at puncture site||1|
|High blood pressure *||1|
|* Presented transiently during compression|
The results obtained are comparable to those reported in international studies (Table III).1
|Table III Studies published on management of trigeminal neuralgia|
|Number of cases||Years of follow-up||Improvement
|Apfelbaum||1982-1983||289||0.5 to 5||66||34||1|
|Breeze and Ignelzi||1982||52||4.5||71||15||0|
|Taarnhoj||1982||350||Up to 11.5||64||32||1.1|
|Piatt and Wilkins||1984||105||Average 4||75||24||0.9|
|Kolluri and Heros||1984||72||> 3 years||78||22||0|
|Szapiro,et al.||1985||68||1 to 5 years||82||12||1.4|
|Bederson and Wilson||1989||252||0.5 to 16||74||17||0|
|Dahle,et al.||1989||54||3 to 7||79||21||0|
|Sindou,et al.||1990||120||Average 2.4||79||21||0|
|Klun||1992||178||0.5 to 12||94||3||1.4|
|Yamaki,et al.||1992||60||0.5 to 5.5||63||15||ND|
|Walchenbach, et al.||1994||50||0.7 to 12||74||26||0|
|Mendoza and Illinworth||1995||133||0.5 to 15||71||13||0.7|
|Barker,et al.||1996||1185||1 to 20||76||24||0.2|
|Komodo||2001||281||5 to 20||81||13||ND|
|Ashkan and Marsh||2004||80||Average 2.6||74||26||0|
|Fernandez-Carballal,et al.||2004||52||> 2 years||65.4||34||0|
|Sandoval-Balanzario,et al.||2014||73||1 to 5 years||88||12||0|
TN is considered a primary disease in adults and its pathophysiology is related to vascular compression.13 It is thought that age and atherosclerosis cause arterial elongation, which in turn promotes the approximation and contact of the arteries with the trigeminal nerve. This can become a true pulsating compression on nerve V, which in turn results in demyelination and axonopathy. In histopathological studies it is clear that the part of the nerve most susceptible to these changes is the root entrance area.14 Such changes reduce the pain threshold of the nerve, so that sensory stimulation evokes a spontaneous burst perceived as pain lasting a few seconds or minutes.14 Not all cases of TN are vascular, Ishikawa et al. provide a hypothesis that states that arachnoiditis and the formation of arachnoid adhesions can cause abnormal angulation of the trigeminal nerve, resulting in nerve hyperexcitability,14 this being a cause of trigeminal pain. Various factors should be evaluated before performing surgical or percutaneous treatment, such as the type of pain (TN type 1 or type 2), comorbidity, and patient age.13
In 1920, Dandy devised an alternative to the surgical approach for partial section of the trigeminal through lateral suboccipital craniectomy, which was termed the "cerebellar approach". This approach provides exposure of the trigeminal nerve near its origin. It was not until 1967 that Peter Jannetta became the first neurosurgeon to explore the cranial nerves in the posterior fossa using a surgical microscope, with the idea that the TN was secondary to neurovascular compression. Since then it was a widely accepted theory and the surgical procedure became popular worldwide for the treatment of TN.15
In our institution MVD has been practiced for a little over 20 years and it now corresponds to 1.5% of all surgeries. In this article we present our experience over 8 years. Miller et al. reported 144 patients with TN and reported that in patients with TN type 1 the cause was found to be arterial compression, MVD improved symptoms with pain-free periods greater than 2 years, while in patients with TN type 2, in whom the etiology was venous compression in some cases and undetermined in others, pain-free periods after MVD were less than two years.13
Rughan et al. reported a total of 3273 patients diagnosed with TN treated through MVD whose average age was 57 years, of which 31.5% were under 65 and 10.7% over 75 years. The mortality rate was 0.68% for patients aged 65-74 years, whereas in patients over 75 years it was 1.16%. In patients under age 65, the mortality rate was 0.13%.16 Wook et al. described 141 patients treated with MVD who were followed over a period from 6 months to 10 years.17 They showed that in 85% of cases immediate pain relief was achieved, in 13% partial relief, and in 3.6% there was no relief.17 In 91% of cases pain remission remained for 1 year, while about 76% of patients remained pain-free for 5 years.17
Zhang et al. reported 154 patients followed for 6 months to 8.8 years (with median follow-up of 5.6 years after MVD. After 5 years of follow-up, 103 patients (72%) were free of pain without ANM, 41 patients suffered from pain to different degrees, and 10 patients were lost to follow-up. The percentage of complete pain relief at 5 years without ANM in the typical TN group (77/96 cases) was 80%, much higher than in the group of atypical TN (26/48 cases), 54%.18
In our experience MVD in the management of TN presented few complications, which were transient, and remaining pain-free at 5 years was observed in 88% of cases; the results are comparable to world literature.
In 1952, Taarnhøj described decompression of the dorsal root of the trigeminal nerve above the margin of the petrous ridge,19 while Pudenz and Shelden described decompression of the second and third divisions of the trigeminal nerve.20 The original work of Taarnhøj and Shelden et al. was the basis for Mullan and Lictor, who in 1983 introduced the percutaneous compression of Gasser’s ganglion.21 The aim is to mechanically traumatize the trigeminal ganglion and preganglionic rootlets using a Fogarty catheter inserted percutaneously and introduced through the foramen ovale.21 In 1974, Sweet and Wepsic introduced radio frequency generated by thermal energy to lesion the trigeminal preganglionic rootlets in Meckel’s cave.22 They also integrated the use of short-acting anesthetic agents, electrical stimulation for precise location, and temperature control to more accurately control the lesion.
At our institution, the only percutaneous procedure used for the last 20 years has been PBM. No other percutaneous procedures such as radiofrequency are done. For just over 15 years, we have reserved PBM for cases in which comorbidity or age increased surgical risk.
Feng et al. collected 120 cases treated by PBM.23 Follow-up at 2 years found a 94.5% remission of pain after surgery, while 5.5% of patients showed no relief from their symptoms. Eleven patients had recurrence during the follow-up period, representing a recurrence rate of 9.2%.23
Jyi et al. reported 130 patients managed with PBM followed over a period of 10 years.24 The recurrence rate was 18.9% at 3 years and 29.5% at 5 years; the overall rate of recurrence during the follow-up period was 37.7%. Only two patients (1.5%) had severe dysesthesia 3 months after the operation. The symptom-free period of patients during the period of 10 years was 61%.24
In our experience with PBM for 8 years, although few cases, we observed that 77% of patients remained pain-free long-term, and permanent complications were mild and rare, according to the literature.
Radiosurgery is currently used as a noninvasive procedure for managing TN.25 Douglas et al. conducted a multicenter study that reported 50 patients undergoing Gamma Knife with 4-mm isocenter aimed at the nerve root entry area in doses ranging from 60 to 90 Gy.26 Thirty-two patients had undergone previous surgery, and the average number of procedures that had been made was 2.8 (range 1-7). Six percent of cases had facial paresthesia after radiosurgery, fully resolved in one case and in another with partial improvement. No patients developed other deficits or deafferentation pain. The median duration of follow-up after radiosurgery was 18 months (range 11-36 months). The median time to response was 1 month (range 6.7 months 1 day). After their last follow-up examination, 56% had resolution of pain, 32% had a result classified by the authors as good, that is between 50-90% subjective improvement, while treatment failed in 12%. Three patients had recurrence of pain at 5, 7, and 10 months after a good initial result, and were subjected to additional surgery. Two years after radiosurgery, 54% of patients were free of pain and 88% had pain relief of at least 50%. This is a noninvasive procedure, which has not yet reached the good and lasting results given by MVD.
Lim reports 41 patients treated with Cyber Knife with a mean dose of 65 Gy (range 60-70 Gy).27 Thirty-eight patients (92.7%) experienced initial pain relief in a median of 7 days after treatment (range, 24 hours-4 months). Pain control was classified as excellent in 36 patients (87.8%), moderate in two (4.9%), and three (7.3%) reported no change. Six (15.8%) of the 38 patients with initial pain relief experienced recurrence at a median of 6 months (range 2-8 months). The rate of long-term response after a median follow-up of 11 months was only 78% (32 of 41) compared with the initial 92.7%. Six (15.8%) of the 38 patients with initial pain relief experienced a recurrence of pain at a median of 6 months (range 2-8 months) after treatment. Besides pain relapse, two patients in this group had new hypoesthesia, while four had numbness.27
In our experience, we observed that TN is a relatively frequent disease compared to the incidence reported in other countries. MVD is the invasive technique of choice in our institution for the treatment of this highly disabling disease, with very similar results to what is shown in world literature.
Conflict of interest statement: The authors have completed and submitted the form translated into Spanish for the declaration of potential conflicts of interest of the International Committee of Medical Journal Editors, and none were reported in relation to this article.