Neurovascular compression in trigeminal neuralgia: a clinical and anatomical study

Abstract

Neurovascular decompression is a widely practiced technique for the treatment of trigeminal neuralgia, and yet there is still debate as to whether the beneficial effect results from relieving the nerve of compression by an anatomically abnormal vessel or from the manipulation and trauma the nerve undergoes during the procedure. The development of this operation has been hampered by the lack of adequate anatomical studies in normal controls. The authors present a combined study of clinical and anatomical material employing standardized definitions of the neurovascular relationships in both groups. Detailed simulations of the operative procedure were carried out on fresh cadavers matched for age, sex, and side, and a technique of in situ blood vessel perfusion was developed that enabled the normal neurovascular arrangement to be observed post mortem at physiological pressures. Neurovascular compression, typified by a large vessel distorting and creating a groove in the fifth cranial nerve, was found in 37 of the 41 cases of trigeminal neuralgia; recurrence of pain did not relate to the site of compression. A follow-up study was carried out for a median of 53 months (range 12 to 103 months). No distortion was found in a total of 50 normal cadaveric dissections; however, on perfusion to physiological pressures, the percentage of nerves with vessels adjacent or in simple contact increased from 16% to 40%. This study using this new technique confirms that vascular compression of the fifth cranial nerve is an anatomical abnormality specific to trigeminal neuralgia.

Treatment options in trigeminal neuralgia

“…They found that 39 of 41 TN patients had a nerve vessel conflict and the vessel created a groove in the trigeminal nerve. That groove was not present in 50 control subjects, even though 40% of them did show a nerve vessel conflict when physiological blood pressures were applied [Hamlyn and King, 1992]. Unfortunately, modern imaging techniques are unable to pick up this groove within the trigeminal nerve.…”

Trigeminal neuralgia occurs and recurs in the absence of neurovascular compression

“…1 A review of autopsy studies reveals some degree of contact between the trigeminal nerve and a blood vessel in 90%-100% of patients with TN, but also in 16%-58% of patients without TN. [16][17][18][19] In 2009, Miller et al, 35 evaluated neurovascular compression (NVC) in patients with and without TN and concluded that trigeminal NVC occurred in asymptomatic patients but was more severe and more proximal in patients with TN. A review of the literature reveals that a wide range (4%-89%) of TN patients has no demonstrable vascular contact.…”

“…A review of the literature reveals that a wide range (4%-89%) of TN patients has no demonstrable vascular contact. [2][3][4]12,19,24,26,34 For example, Leal et al 26 reported no NVC in 9% of patients by surgical exploration, and imaging revealed no vessel in relation to the nerve in 12% of patients. There are also reports in which all patients have NVC.…”

MVD for trigeminal neuralgia; neuralgia revisited with review of literature

“…12,16 In idiopathic TN nerve compression is by a vessel as it exits the medulla oblongata, this theory is supported by the success of MVD in the treatment of compression of trigeminal nerve. 21 TN usually begins as a relapsing disease with pain-free intervals, which sometimes can last for months or years.…”

“…8,9 It is shown that in about 96% of cases of typical TN, vascular compression is to be found in only 3% of people without TN, there is a vascular contact with the trigeminal nerve. [10][11][12] The pathological substrate is located in the building of the cranial nerves. In the brain stem the oligodendroglia are responsible for axonal isolation, and outside brain stem is Schwann cells.…”