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Table of Contents    
CORRESPONDENCE
Year : 2016  |  Volume : 64  |  Issue : 6  |  Page : 1392-1393

Author's reply: Surgical approaches to trigeminal neuralgia


Department of Neurosurgery, Chettinad Hospital and Research Institute, Kelambakkam, Chennai, Tamil Nadu, India

Date of Web Publication11-Nov-2016

Correspondence Address:
Vengalathur Ganesan Ramesh
Department of Neurosurgery, Chettinad Hospital and Research Institute, Kelambakkam, Chennai, Tamil Nadu
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0028-3886.193765

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How to cite this article:
Ramesh VG. Author's reply: Surgical approaches to trigeminal neuralgia. Neurol India 2016;64:1392-3

How to cite this URL:
Ramesh VG. Author's reply: Surgical approaches to trigeminal neuralgia. Neurol India [serial online] 2016 [cited 2019 Nov 20];64:1392-3. Available from: http://www.neurologyindia.com/text.asp?2016/64/6/1392/193765


Sir

The treatment of medically intractable trigeminal neuralgia is continuously evolving from the early days of neurosurgery. Peripheral neurectomies, open rhizotomies, both utilizing the middle fossa and posterior fossa approach, compression–decompression surgery, and brain-stem trigeminal tractotomies have given way to modern procedures such as open microvascular decompression (including neuroendoscopic vascular decompression), percutaneous procedures (including radiofrequency thermocoagulation, percutaneous glycerol rhizotomy, percutaneous microballoon compression), and noninvasive methods such as radiosurgery. The rationale and choice of individual methods has been a matter of debate. It has to be accepted that the pathogenesis of trigeminal neuralgia is still controversial and that no method of treatment guarantees 100% freedom from recurrence.[1],[2]

One has to decide the method of treatment of trigeminal neuralgia based on other factors, namely, age, other medical comorbid factors, cost of treatment, length of hospitalization, cost of equipment, major postoperative neurological deficits and mortality.

Microvascular decompression: This presumes neurovascular conflict at the trigeminal root-entry zone as the cause of trigeminal neuralgia; decompression of the nerve from the compressing blood vessel is considered to relieve the pain. This procedure gives the longest lasting pain relief with the least frequency of recurrence and no trigeminal sensory deficit/dysesthesia or motor deficit.[3] However, this is a major neurosurgical procedure performed under general anesthesia. The patient needs hospitalization for a few days. Hence, the cost of this procedure is high. The convalescence may take a few weeks. This procedure has other potential complications such as cerebrospinal fluid leaks, infarction, hematoma, and ipsilateral hearing loss. There is also a potential risk of mortality of 0.2–0.5%. The use of neuroendoscope for this procedure may reduce the risk of abovementioned complications because of minimal exposure and minimal cerebellar retraction.

Percutaneous radiofrequency thermocoagulation: This is a percutaneous procedure involving the placement of a radiofrequency probe through the foramen ovale and selective lesioning of the involved division of the trigeminal sensory root proximal to the  Gasserian ganglion More Details.[4] This requires a costly radiofrequency lesion generator, probe, etc., Selective lesioning of the involved division is possible. The procedure requires some sedation or general anesthesia. There is some postoperative hypoesthesia. As lesioning of the ophthalmic division can cause corneal anesthesia and keratitis, it is not suitable for trigeminal neuralgia involving the first division.

Percutaneous microballoon compression: This is a percutaneous procedure that involves passing a microballoon catheter through the foramen ovale and transient compression of the sensory root by inflating the balloon.[5] This is a procedure performed under general anesthesia in the operating room. Trigeminal motor weakness is a frequent complication of this procedure apart from some hypesthesia.

Percutaneous retrogasserian glycerol rhizotomy: This is a percutaneous procedure involving passing a spinal needle through the foramen ovale and injecting a small quantity of anhydrous glycerol into the involved division. This is said to selectively lesion the pain carrying small sensory fibers while sparing the large myelinated fibres.[6],[7],[8] This can be done under local anesthesia with/without mild sedation and is an outpatient/day-care procedure. No special equipments are needed and hospitalization is usually not required. There is some hypoesthesia or dysesthesia, which is usually transient.

Radiosurgery: This is noninvasive method that involves focusing a beam of radiation at the trigeminal sensory root at the root-entry zone in the posterior fossa.[9] This usually involves the radiosurgery equipment and is done as an outpatient procedure. It takes several weeks for the onset of pain relief. Cost is another major constraint.

All the above procedures give immediate pain relief except the radiosurgery procedure. Microvascular decompression and radiofrequency lesioning have a relatively longer duration of pain relief and lesser recurrence rate compared to the other procedures. Though the microvascular decompression is a “nonablative” procedure and does not produce sensory or motor trigeminal deficits, it is a major invasive neurosurgical procedure involving hospitalization and cost. Though small, there is a risk of major morbidity and mortality. It may not be suitable for very old patients with medical comorbidities. Radiosurgery is a safe, noninvasive option. However, the major constraints are the cost and a prolonged duration for the onset of pain-relief. Among the minimally invasive percutaneous procedures, radiofrequency thermocoagulation provides a good pain relief with relatively less recurrence rate. However, it involves the use of costly equipment, general anesthesia or sedation. Hypoesthesia and corneal anesthesia are major issues. This procedure may not be suitable for trigeminal neuralgia involving the ophthalmic division. Percutaneous microballoon compression does not involve any costly equipment and gives immediate pain relief. However, it has to be performed under general anesthesia and has the highest recurrence rate among the percutaneous procedures; trigeminal motor weakness is a major complication of this procedure. Percutaneous glycerol rhizotomy is a simple procedure which does not involve any costly equipment, can be done under local anesthesia or mild sedation, and can be done as an outpatient or day care procedure.[6] It gives an effective and immediate pain relief and recurrence rate is comparable to the other procedures. The major advantage is that it can be safely repeated in patients with recurrence. Sensory impairment is only mild and the procedure can be safely performed even for patients with ophthalmic division neuralgia. The only major complication may be a transient dysesthesia, which is usually dose related.

Hence, the present day treatment for intractable trigeminal neuralgia ranges from major, invasive microvascular decompression to minimally invasive cost-effective percutaneous procedures, and noninvasive, costly radiosurgery. Due to its relatively longer duration of pain relief and lesser recurrence rate, microvascular decompression is preferred in younger, medically fit patients. The use of a neuroendoscope for microvascular decompression requires a longer learning curve and it may find a wider use in the future. The percutaneous procedures, especially glycerol rhizotomy, is preferable for older patients with medical comorbidities, who are not fit to undergo a major invasive surgical procedure. However, the ultimate deciding factor is the patient's own informed choice.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

 
  References Top

1.
Ramesh VG, Premkumar G. An anatomical study of the neurovascular relationships at the trigeminal root entry zone. J Clin Neurosc2009;16:934-6.  Back to cited text no. 1
    
2.
Ramesh VG. Pathogenesis of trigeminal neuralgia. Neural Regen Res 2014;9:877.  Back to cited text no. 2
[PUBMED]  Medknow Journal  
3.
Barker F, Jannetta P, Bissonette D, Larkins M, Jho HD. The long-term outcome of microvascular decompression for trigeminal neuralgia. N Engl J Med 1996;334:1077-83.  Back to cited text no. 3
    
4.
Taha JM, Tew JM Jr. A prospective 15-year follow up of 154 consecutive patients with trigeminal neuralgia treated by percutaneous stereotactic radiofrequency thermal rhizotomy. J Neurosurg 1995;83:989-93.  Back to cited text no. 4
    
5.
Brown J, Gouda J. Percutaneous balloon compression of the trigeminal nerve. Neurosurg Clin North Am 1997;8:53-62.  Back to cited text no. 5
    
6.
Kodeeswaran M, Ramesh VG, Saravanan N, Udesh R. Percutaneous retrogasserian glycerol rhizotomy for trigeminal neuralgia: A simple, safe, cost-effective procedure Neurol India 2015;63:889-94.  Back to cited text no. 6
    
7.
Waltz T, Dalessio D, Copeland B, Abbott G. Percutaneous injection of glycerol for the treatment of trigeminal neuralgia. Clin J Pain 1989;5:195-198.  Back to cited text no. 7
    
8.
Ischia S, Luzzani A, Polati E. Retrogasserian glycerol injection: A retrospective study of 112 patients. Clin J Pain 1990;6:291-6.  Back to cited text no. 8
    
9.
Kondziolka D, Lunsford D, Habeck M, Flickinger J. Gamma knife radiosurgery for trigeminal neuralgia. Neurosurg Clin North Am 1997;8:79-85.  Back to cited text no. 9
    




 

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