OROFACIAL PAIN
of complex neurosurgical procedures such as
microvascular decompression and percutaneous
radiofrequency thermal rhizotomy, this mode of
treatment has gradually fallen out of favor. In fact,
one finding that is often overlooked by opponents
of this procedure is the favorable outcome of
pain relief of 5 years or more reported by Murali
and Rovit in their group of patients who were first
treated with radiofrequency thermocoagulation,
followed by peripheral neurectomy after the
recurrence of pain.24 There have been some
revivals in the last 5 years as more oral surgeons
in the Indian subcontinent reported their use for
treating patients who were living in the rural area
and were deprived socio-economically of modern
neurosurgical facilities.7, 25, 40, 41
Proponents of peripheral neurectomy think that this
procedure still has a role to play with the elderly,
medically compromised patients or those not keen
to be subjected to extensive neurosurgery.18, 24, 39
The surgical techniques employed in this case
were essentially the same as described by HongSai.10 The average pain free period achieved has
been reported to be longer than that accorded
by cryotherapy and lasted between 24-36 months
similar to that reported by many authors.12, 25, 30
Grantham and Segerberg30 who electrocauterized
the remaining nerve stump after performing nerve
avulsion, reported to have achieved a wide range,
from no improvement to pain relief up to 8 years.
Yadav et al. 7 however, recently reported that 25%
of their Indian patients who underwent peripheral
neurectomy suffered from recurrence of neuralgia
within 6 months post surgery. Another study
reported a recurrence rate of 78% in patients who
had undergone peripheral neurectomy during
a mean follow up of 7 years. Worse, half of these
patients had their first recurrence within a month42
Quinn and Weil reported finding bony foramina
being filled with natural bone during the second
and third neurectomies, with the foramina
becoming smaller in size between each surgery.
Hence they did not think plugging with bone or
amalgam was useful as they claimed natural bone
would fill these foramina up.12
Such an occurrence has not been observed in
this case, hence the need to obliterate it with a
compatible material. Hong-Sai reported that the
duration of pain relief could extend up to at least
4 years in the cases where titanium screw insertion
was performed.10
Ali et al.41 in their prospective study found that the
placement of a stainless screw into the foramen
significantly increase the duration of remission.
However, as their number of samples was small,
and the duration of review was only 24 months, it
remains to be seen if such is still the case several
years later.
The insertion of a screw into a foramen following
peripheral neurectomy is not new either, having
been first reported by Beckmann almost one
century ago.43 Even then, he noticed that the
patient with a screw inserted experienced longer
136
remission period than others. It is believed that
this case presents the longest duration of pain
remission associated with the obliteration of
foramina.
It has been reported that the recurrence of
trigeminal neuralgia can happen at the same
branch or progress to other neighboring
branch(es). Yadaz et al.7 were of the opinion that
patients who have successful surgeries often
need secondary or tertiary surgeries on different
trigeminal nerve branches due to migration of
pain. This is evident in the current case, where she
experienced recurrence in the same nerve initially,
and when successfully treated, migrated to other
branches.
Several authors discussed the number of repeated
neurectomies for peripheral nerves. 9, 24, 39
Sung was of the opinion that peripheral neurectomy
was suitable for incipient cases, and once there is a
progression to other branches, intracranial surgery
was preferred.9
Cerovic39 reported that the remission time
decreased after repetitive neurectomies.
They did not think repeating the surgery on the same
nerve more than three times was of any benefit.39
As shown in the current case, the patient had
exhausted her medical therapy of carbamazepine
and all peripheral surgical treatment options,
namely repeated alcohol injections, cryotherapy
and repeated peripheral neurectomies. Worse,
in her case recurrence happened with pain
progression to the neighboring nerve branches.
In accordance to the “ladder of treatment for
trigeminal neuralgia”, she eventually progressed
to undergo intracranial surgery with apparently
good outcome. It is interesting to note how
resilient the trigeminal nerve can become when it
has been affected by neuralgia. During repeated
operations, the author and colleagues noticed
that her peripheral nerves had regenerated into
fine branches. This is similar to that reported by
Quinn and Weil.12, 16 It is interesting to note that
within nine months following neurectomy of the
incisive nerve, the nerve fiber had re-grown and
coiled itself around the titanium screw in the
incisive foramen. It seems as if the nerve was able
to negotiate the gaps between the screw and the
foramen and loosened the screw in the process of
regeneration. This may also explain why bone wax
was not able to block nerve regeneration.
It is known that the triggering stimulus is carried
by the large myelinated axons and nociception is
associated with the activation of small rnyelinated
A-delta and unmyelinated C-fibers. 44
As study has shown that small myelinated and
unmyelinated nerve fibers recover faster than the
larger A-alpha myelinated fibers45, it was decided
at the subsequent neurectomy that some material
should be used to obliterate the foramen so that
the nerve cannot regenerate to the area it originally
supplied.
A titanium screw was chosen because of its
biocompatibility and ease of handling. I