Trigeminal Neuralgia
Short Summary

44-year-old female that presents with Paresthesias and weakness in the right arm and hand, and left trigeminal neuralgia. The patient underwent operation of microvascular decompression of the left cranial nerve. Following the operation she experienced marked improvement of her facial pain and paresthesias, but eight months later the same symptoms recurred. Now the patient is on Tegretol without complete and persistent alleviation of pain. At a recent consultation, the neurosurgical specialist stated that a second operation is not an option because of adhesions.

Patient's Questions
1)    What therapy do you suggest?
 
2)    Is it possible a solving surgical therapeutic approach? In particular do you agree with the operation suggested by the patient's doctor?
 
3)    Can you indicate Centers of Excellence in Italy?
Medical Background

Diagnosis : Trigeminal Neuralgia
Age :44 , female
Medical History
Since 2000 paresthesias in the zone of C7-T1 on the right and grasping deficit of her right hand.  An MRI imaging of the spine was performed in 2003 revealing disc hernias at levels C6/C7/C8.  In consequence of the appearance of left trigeminal neuralgia a differential diagnosis of multiple sclerosis was suggested.  An immunoelectrofocusing of CSF was negative.
About two and a half years ago appearance of pain on the left side of the jaw following tooth drawing.
A period of approximately 1 year followed with lack of symptoms.
About one and a half year ago appearance of typical pain in the zone of V2-V3 on the left, brought back by mastication, phonation and tactile stimulus. Furthermore, paresthesias in the same left area at the tactile stimulus were reported. During the following months appearance of pain in the left V1 zone too. The typical pain crisis were never followed by a period of complete remission. A Tegretol therapy was defined. On 03. 2007 an MR imaging of the brain with contrast medium was performed showing a small signal alteration near the left basal ganglia, revealing a capillary telangectasia, remained unchanged if compared with a previous one performed in 2006. The patient was, therefore, hospitalized at the neurosurgery ward at S. Giovanni Battista Hospital in Turin where she underwent, on 06/2007, an operation of “Microvascular decompression of the left fifth cranial nerve according to Jannetta." The postsurgical course was within normal limits with a negative brain CT scan due to current complications. At discharge, the neurological objective examination highlighted a clear reduction of the typical pain and of the paresthesias in left trigeminal territory. Slight diplopia in the sight downward and to the right , in progressive improvement. A further follow-up cranial CT scan on 06/2007 was performed, in which, compared with the previous one, it was noticed a regression of the hygroma in the left frontal region near the convexity with persistent small enlargement of the cisternal spaces in left posterior fossa. Furthermore, on 07/2003 an EMG (Electromyography) of some muscles of the right superior limb was performed giving indication of the presence of a neurogenic suffering, with denervation activity in muscle districts involving the C7-C8-T1 nerve roots on the right.
Eight months after operation on 06/2007, the pain symptomatology reappeared as at the beginning of the pathology. Therefore, in May a Lyrica therapy 75mg at a dosage of 1 tablet three times a day + Neuramide intramuscular vials was defined; this therapy went on for 20 days and thereafter, being this inefficacious, it was modified in the following way: Tegretol 200 mg CR at a dosage of 1 tablet twice a day + Dobetin 500 at a dosage of 2 vials a week. In this case too, the length of the therapy was of about 20 days and, being this inefficacious, it was still further modified. Following the suggestions of the treating specialist, Tegretol was increased to 3 tablets a day suspending the administration of Dobetin. For about 7-10 days the pain symptomatology reduced to get back later to the initial level. Tegretol was, therefore, still further increased to 4 tablets a day.
In October 2008 the patient, due to the persisting pain symptomatology, has been visited by the neurosurgery specialist who confirms a relapse with presence of adhesions and impossibility of another surgical operation. The doctor, then, suggests to increase the Tegretol dosage explaining that the patient can rise to 8 tablets daily.
 At present the patient is under therapy with Tegretol 200 mg CR at a dosage of 5 tablets daily without being able to have a complete and persistent covering from pain; actually, in the periods when the symptoms are stronger, Tegretol is integrated with Tachidol or Toradol. From the medical report of the last neurosurgical specialist visit on 11/2008 the therapeutic indication of the doctor are reported, consisting in the continuation of the pharmacologic therapy; with the possible thermocoagulation of Gasser's ganglion be used only in case of absolute need.

Expert's Opinion

This is a 44 woman that presents with two major neurological problems:
a. Paresthesias and weakness in the right arm and hand. b. left trigeminal neuralgia.
 
The paresthesias and weakness in the right hand seem most likely to be due to cervical radiculopathy. The clinical presentation of sensory symptoms in the distribution of specific dermatoms (C7-T1), the cervical MRI findings, and the EMG findings of denervation activity in C7-T1 muscles – all point that the paresthesias and weakness in the right hand are caused by cervical root compression secondary to herniated discs.
 
The patient’s facial pain is typical for trigeminal neuralgia. Repeated MRI showed only capillary telangectasia in the left basal ganglia, which remained unchanged and seem to be an incidental finding. The MRI study did not reveal any findings suggestive of multiple sclerosis or any lesion (for example CPA mass) that may compress the trigeminal nerve. Moreover, the clinical course is inconsistent with multiple sclerosis.
 
Therefore, it seems that the patient has classic (idiopathic) trigeminal neuralgia (CTN). CTN encompasses also cases with potential vascular compression of the fifth cranial nerve.
 
In this case I can think of three main therapeutical approaches:
a. pharmacological
b. invasive (Gasserian ganglion rhizotomy)
c. radiotherapy (Gamma knife surgery).
 
Pharmacological treatment can consist of monotherapy or combination therapy. Generally if tolerated Tegretol can be increased up to 2,400 mg a day. Other drug that can be used are: Lamotrigine, Gabapentine or Valproate. In my experience, I had several patients that showed a favorable response to Topiramate. Some other responded well to combination of Tegretol with Valproate, or Tegretol wth Lyrica. Opiods such as Oxycontin can also be used in combination. There are not strict guidelines regarding pharmacological therapy for TN, and one should try several drugs in various combinations in order to achieve efficacy. Only if maximal pharmacological therapy fails other approaches should be considered.
 
Percutaneous procedures on the Gasserian ganglion, as the patient's doctor suggested, are a well known and well recognized treatment for TN. I agree with Dr the doctor that if maximal pharmacological therapy fails the next step would be Gasserian ganglion lesion (e.g thermocoagulation). According to available data 68-85% of patients will be pain free one year after this procedure. However, the figures fall to 50% after 5 years. It is important to remember that about 50% of patients remain with some degree of sensory loss after this procedure and in some cases troublesome dysesthesias and pain may develop. Gasserian ganglion procedures are practiced in most neurosurgical departments.
 
The third therapeutical approach is gamma knife surgery. In this procedure a beam of radiation is focused at the trigeminal roots at the posterior fossa. Generally, there is less experience with this sort of therapy and it is carried out in specialized centers. There is relatively scarce validated data regarding the efficacy of this therapy. However, it seems somewhat less effective in controlling pain than Gasserian ganglion procedures, but with less postoperative sensory complications.
 
In my opinion, maximization of pharmacological therapy should be tried first. Only if it fails Gasserian ganglion procedure should be considered. Gamma knife surgery should be kept in mind as a future possibility only if Gasserian ganglion procedures fail.

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