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Treatment
Part Two
Barba
and Alksne (1984) reviewed the results of microvascular decompression in
37 patients with trigeminal neuralgia. They found that patients with
trigeminal neuralgia of greater than 9 years' duration had a cure rate
following surgery of only 42%, compared with an 88% cure rate in
patients with symptoms less than 9 years. In addition, in this study,
patients undergoing microvascular decompression as a primary procedure
were cured at a rate of 91%, compared to a 43% cure rate in patients
treated with destructive procedures (e.g., rhizotomies) prior to
microvascular de-compression. The study of Barba and Aklsne thus
suggests that microvascular decompression should be performed early in
the course of trigeminal neuralgia as the first procedure for it to be
maximally effective.
Microvascular
decompression of the trigeminal nerve does have a definite morbidity and
mortality. Jannetta (1977) has reported herpes perioralis, mild
hemiparesis, decreased ipsilateral hearing, and cerebellar infarction
and hematoma after surgery. Pazin et al. (1978) reported that herpes
simplex virus was reactivated within a few days in nearly 60% of
patients who had a history of herpes labialis and underwent
microneurosurgical decompression; however, this complication can
apparently be prevented by the use of human leukocyte interferon for 5
days beginning on the day of operation (Pazin et al., 1979).
With
respect to operative mortality with microvascular decompression,
Jannetta (1977) has reported only four postoperative deaths among over
450 patients and none in his last 200 patients. Taarnhoj (1982) reported
only one death among 120 patients who underwent this procedure. Jannetta
has emphasized, however, that the procedure may be difficult to perform
and must be carefully learned if the surgeon is to avoid making
inaccurate observations and causing unnecessary morbidity and mortality.
Several
investigators (Apfelbaum, 1977; Burchiel et al., 1981; Ferguson et al.,
1981; Van Loveren et al., 1982) have compared the effects of
percutaneous radiofrequency trigeminal rhizotomy and microvascular
decompression of the trigeminal nerve. In Apfelbaum's (1977) series of
103 consecutive patients with trigeminal neuralgia, 48 patients
underwent radiofrequency rhizotomy and 55 patients underwent
microvascular decompression. Successful initial relief of pain was
achieved in 88% of patients in the first group and 96% of patients in
the second group. Severe recurrences occurred in 13% of patients who
underwent radiofrequency rhizotomy and in only 5% of patients who
underwent decompression. Of the patients who underwent radiofrequency
rhizotomy, seven developed corneal anesthesia, six developed anesthesia
dolorosa or severe dysesthesia, and one developed trigeminal motor loss.
In addition, one patient suffered an intracerebral hematoma, and one
patient developed a temporal lobe abscess. There were no postoperative
deaths. Of the patients who underwent microvascular decompression, two
developed transient fourth nerve palsies, two developed mild hearing
loss, two developed a cerebellar syndrome, one patient had a pulmonary
embolism, and one patient developed severe hearing loss associated with
ipsilateral sixth and seventh nerve palsies. There were no operative
deaths. Apfelbaum has concluded that both percutaneous radiofrequency
trigeminal rhizotomy and microvascular decompression are effective
procedures for the initial relief of trigeminal neuralgia that is
unresponsive to medical therapy. Because micro-vascular decompression
requires a craniotomy, there is greater potential risk to the procedure;
however, absence of altered facial sensation, corneal anesthesia, or
dysesthetic complications in the postoperative period are definite
advantages of this procedure. In addition, this approach offers those
few patients with unsuspected, small tumors the advantage of early
discovery and cure. Finally, according to Apfelbaum, patient
satisfaction with microvascular decompression is higher than with
radiofrequency rhizotomy.
In the
series reported by Burchiel et al. (1981), 42 patients underwent
microvascular decompression for trigeminal neuralgia, while 78 patients
underwent PRTR. In this series, the success rate of microvascular
decompression (90%) was higher than that of PRTR (64%). In the group of
patients who underwent micro-vascular decompression, there were only two
complications. One patient developed bifrontal chronic subdural
hematomas, and a second patient developed severe systemic hypertension
and a subsequent cerebellar hematoma 4 hours postoperatively, eventually
resulting in death. In the group of patients who underwent PRTR, 8%
developed complications including neuroparalytic keratitis, anesthesia
dolorosa, and significant facial paresthesias, although there were no
deaths.
In the
series reported by Ferguson et al. (1981), 55 patients underwent PRTR,
while 24 patients underwent microvascular decompression. In neither
series was there an overwhelming success rate, with only 54% of patients
who underwent PRTR and 71% of patients who underwent microvascular
decompression remaining free of pain over a follow-up period of about
28---30 months. In the patients who underwent PRTR, there were no deaths
and no lasting complaints of numbness or dysesthesia. Anesthesia
dolorosa occurred in only one patient, and corneal anesthesia occurred
in only four patients, with none of the patients having any evidence of
neuroparalytic keratitis. Similarly, there were no major complications
in patients who underwent decompression. There were no deaths, and one
patient required evacuation of a small cerebellar hematoma. Several
other patients experienced transient vertigo and ataxia, one patient
developed a transient fourth nerve palsy, and several patients
complained of mild facial numbness or weakness.
Van
Loveren et al. (1982) treated 750 patients with trigeminal neuralgia who
had failed on medical therapy. Fifty patients underwent microvascular
decompression, of whom 84% were pain free after 3 years. Only 12% had
recurrence of their neuralgia. The remaining 700 patients were treated
with PRTR. Of these patients, 74% had results that were considered
excellent or good, and only 20% of patients had a recurrence of their
pain over a 6-year follow-up period. Van Loveren et al. concluded that
there was no significance in results between microvascular decompression
and PRTR, but since PRTR is a simpler procedure to perform, it is the
treatment that they favor.
Not all
investigators have had such excellent results in the surgical treatment
of trigeminal neuralgia. Breeze and Ignelzi (1982) have reported their
experience with 51 consecutive patients with trigeminal neuralgia who
underwent microvascular decompression. While they had an 85% early
success rate, 13% of the patients developed a recurrence of pain over a
4-year period. In addition, 60% of these patients experienced some form
of transient or permanent complication.
In the
final analysis, it would seem clear that neither microvascular
decompression nor percutaneous radiofrequency trigeminal rhizotomy
should be performed by the inexperienced neurosurgeon, but that in the
proper hands, both procedures represent relatively safe and effective
measures for the treatment of trigeminal neuralgia.
Adams
et al. (1982) have performed posterior fossa microsurgery on 57 patients
with trigeminal neuralgia. Fifty-four of these patients underwent either
partial or total section of the trigeminal sensory root, two had
microvascular decompression operations, and one patient had both a
partial sensory root section and micro-vascular decompression. Over a
mean follow-up period of 4.5 years, 52 of 54 patients (96%) had either
no further pain or suffered only minor twinges requiring no treatment.
In
addition to percutaneous radiofrequency trigeminal rhizotomy and
microvascular posterior fossa surgery, several other procedures have
been advocated for the treatment of patients with trigeminal neuralgia.
In a report from the Karolinska Institute in Stockholm, 75 patients were
treated by injection of glycerol into the trigeminal cistern (Hakanson,
1981). Long term follow-up showed alleviation of pain with minimal or no
disturbance of facial sensation in the majority of the patients.
Injection of glycerol into the trigeminal cistern is a stereotactic
procedure that may have the benefits of reduced anesthesia time, minimal
complication rate, and excellent result. Hakanson has suggested that the
glycerol may act primarily on partly demyelinated nerve fibers that are
presumed to be involved in the trigger mechanisms that produce
trigeminal neuralgia.
Mullan
and Lichtor (1983) have reported their results in patients with
trigeminal neuralgia whom they treated by percutaneous microcompression
of the trigeminal ganglion using a balloon catheter. During a follow-up
period that ranged from 6 months to 4 ½ years, 44 of 50 patients (88%)
remained free of pain. According to Mullan and Lichtor, the advantages
of this technique are freedom from patient discomfort, ease of
performance of the procedure, absence of associated mortality, and a
minimal morbidity rate. One patient developed a trochlear nerve palsy 2
days following the procedure. Although this patient was shown to have a
small dural arteriovenous malformation draining into the ipsilateral
cavernous sinus, the role of this malformation in the production of the
palsy is unclear. The palsy disappeared without treatment after about 3
months.
Incision
of the descending trigeminal tract near the cervicomedullary junction
will reliably cause the loss of pain and temperature in the ipsilateral
face and pharynx and usually will relieve the pain of trigeminal
neuralgia (Hosobuchi and Rutkin, 1971). This procedure has been used
only in patients who have failed with both medical and conventional
surgical therapy.
Lende
et al. (1971) have performed combined removal of precentral and
postcentral cortex in two patients with severe facial pain, one of whom
had trigeminal neuralgia refractory to numerous medications and surgical
procedures, including frontal lobotomy! Following cortical removal that
included precentral and postcentral facial representations, both
patients had immediate and lasting pain relief.
Acupuncture
has been used in some areas of the world in the treatment of trigeminal
neuralgia. Yiu and Tam (1976) reported that of 378 patients who
underwent acupuncture for this disorder, 88% achieved initial (over 6
weeks) ``excellent improvement'' in pain although these investigators
did not report long-term results.
The
reader interested in a more complete discussion of trigeminal neuralgia
is encouraged to obtain the excellent publication concerning this entity
edited by Hassler and Walker (1970).
Gamma
Knife: Unpublished reports ( July 2000 ) from our institution
have suggested that Gamma Knife irradiation may be very effective in the
management of refractory trigeminal neuralgia
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