Journal of Clinical Neuroscience (2005) 12(7), 787–789

0967-5868/$ - see front matter ª 2005 Published by Elsevier Ltd.

doi:10.1016/j.jocn.2005.08.001

Clinical study

Microvascular decompression for trigeminal neuralgia:recurrences and complications

Sarah Olson MBCHB (OTAGO)MBCHB (OTAGO), Leigh Atkinson FRACSFRACS, Michael Weidmann FRACSFRACS

Department of Neurosurgery Princess Alexandra Hospital, Woolloongabba, Brisbane, Queensland, Australia

Summary Background. The purpose of this study was to review the complications and pain recurrences after microvascular decompression

(MVD) for trigeminal neuralgia. Methods. This is a retrospective review of 156 patients undergoing MVD in the last 25 years at Princess

Alexandra Hospital, Brisbane, Australia. Patients were contacted by telephone and a questionnaire was used for the interview. Results. The

probability of becoming pain free after MVD in our study was 0.93. There were no deaths and the incidence of serious complication was 2%.

Our complication profile is similar to other authors. Pain recurrences occurred in 18% of patients over a 25 year period. This was most likely

within two years of surgery and thereafter occurred at a rate of 2–3.5% a year. Seventy-four percent of patients were still pain free at 10 years.

In half of the patients the recurrence was not as severe as the initial occurrence of pain. Thirty percent of recurrences occurred on the opposite

side. Eighteen percent of patients were not pain free despite any intervention. Conclusions. Microvascular decompression in experienced

hands has an excellent pain outcome in the majority of patients. Major complications are uncommon.

ª 2005 Published by Elsevier Ltd.

Keywords: microvascular decompression, trigeminal neuralgia, complications, recurrence

INTRODUCTION

Microvascular decompression (MVD) is the most long-lasting andeffective treatment for medically refractory trigeminal neural-gia.1,2 It is often not offered as first line surgical treatment in med-ically refractory trigeminal neuralgia due to the perceived higherrisk of serious complications. These complications are infrequentand the common complications do not influence patient satisfac-tion as long as they become pain free.While bilateral trigeminal neuralgia has been reported, there

have been few reports of trigeminal neuralgia recurring on theopposite side. We also wanted to establish if therapy was lesseffective after a recurrence and review when recurrences werelikely to occur.

METHODS

Between 1977 and December 2002, 266 MVD were undertaken bytwo surgeons at the Princess Alexandra hospital. These were forvarying aetiologies of trigeminal neuralgia, including tumour.This was a retrospective study performed by an independent

investigator. The patients were contacted by telephone and inter-viewed using a questionnaire. One hundred and thirty patientswere able to be contacted. For a further 26 patients the medicalrecord from hospital and follow-up clinics were reviewed. Onlyobjective findings were recorded from the patient notes. Subjec-tive responses such as satisfaction with surgery and preoperativeseverity were not entered for patients who were not able to be con-tacted. For the remaining 110 patients the medical record had beendestroyed after a ten year period of not seeking medical attentionat our institution. For these patients we were able to ascertain thatthey were discharged from hospital alive.

Received 30 March 2004

Accepted 16 August 2005

Correspondence to: Sarah Olson, Department of Neurosurgery Princess

Alexandra Hospital, Woolloongabba, Brisbane, Queensland, Australia.

Tel.: +61 7 3240 2111; Fax: +61 7 3240 5851;

E-mail: sarah.olson@southernhealth.org.au

RESULTS

Sixty-seven percent of our 156 patients were women and 33%were men. Women were statistically more likely to be affected.(Chi squared test comparing binomial proportions, (Pi = 0.6731CI (0.6–0.746), P < 0.0001 (one tail test)).In 58% of patients the initial pain occurred on the right side and

in 42% on the left, (Pi = 0.58 CI (0.48–0.666), P = 0.0521 (one tailtest)). This just fails to reach significance probably due to thepower of the study. Three percent of patients had a first degree rel-ative with trigeminal neuralgia.Of those referred, 17 patients (11%) had had previous surgical

therapy including glycerol rhizotomy, radiofrequency rhizotomy,balloon compression rhizotomy or MVD by another surgeon. Inour study, an MVD resulted in the probability of becoming painfree of 0.93. The probability of becoming medication free was0.94.

Complications

Two patients had medical complications (angina and pneumonia).Three patients were unable to return to all the activities they haddone prior to their operation. Two of these had a postoperative cer-ebellar haematoma and the other had a venous infarct of the cerebel-lum. No patients died as a result of their operation. One patientsuffered anaesthesia dolorosa after surgery. Of the patients withrecurrences and second surgery, 9% had more complications afterthe second operation than the first. Temporary diplopia and perma-nent facial numbnesswere themost common complications (Fig. 1).The overwhelming majority of patients were moderately or very

happy with their outcome (Fig. 2). Of those who were very unhap-py with their outcome, 75% had persistent pain as the cause oftheir dissatisfaction. Testing the hypothesis that having a singlecomplication does not alter satisfaction with surgery was non-sig-nificant. Those that were very satisfied or moderately happy wereequally likely to have had one complication or no complications.However for 2 or more complications the result was significant.

(ML - Maximum likelihood, chi squared = 5.683, P = 0.0227 (onesided)).

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Fig. 3 Timing of pain recurrence after MVD. The majority of recurrences

occurred with 2 years of MVD.

Fig. 4 ‘‘Survival curve” for pain recurrence after MVD. Most recurrences

occurred within 2 years of MVD and the median time to recurrence was 101.24

months.

Fig. 1 Complications from microvascular decompression. The complications

are identified by number - 1. CSF fistula 2. Meningitis 3. Temporary facial

paresis 4. Permanent facial paresis 5. Cerebellar syndrome 6. Wound

infection 7. Temporary hearing loss 8. Permanent hearing loss 9. Functional,

but reduced, hearing 10. Temporary diplopia 11. Permanent dipolopia 12.

Temporary facial numbness 13. Permanent facial numbness 14. Wound pain

15. Pain syndrome 16. Wound numbness 17. Other medical condition.

Fig. 2 Satisfaction with microvascular decompression. Degree of satisfaction

is identified by number- 1. Very unhappy with outcome 2. Moderately

unhappy with outcome 3. Equivocal 4. Moderately happy with outcome 5.

Very happy with outcome.

788 Olson et al.

Significant recurrences

Significant pain recurrence occurred in 28 (18%) of patients overthe 25 year period. In 30% of those patients with recurrences it oc-curred on the opposite side to the original presentation. None ofthese patients had multiple sclerosis.For five patients (3%) the initial operation offered no pain re-

lief. These were the treatment failures. One of these patientshad multiple sclerosis, another had atypical facial pain. In theremaining three no obvious cause of failure was found. Interest-ingly, another patient with MS did obtain relief.The recurrences occurred between two months after the initial

operation and up to 10 years later. Of those patients who re-curred, 52% said the recurrence was not as severe as the firstepisode of pain, while 48% rated it as severe or worse. In44% of patients, recurrent pain occurred on the left and in56%, on the right. This was similar to the distribution at initialpresentation.Of the patients who had pain recurrence, 6% had had a previous

surgical procedure other than the previous MVD, compared to12% who did not have a recurrence. Eighteen percent of patientswho had recurrences were still not pain free despite further inter-vention compared to 7% of patients who hadn’t had a recurrence.Most recurrences occurred within the first two years after MVD(Fig. 3). The median time to recurrence was 101.24 months(Fig. 4).Of patients with recurrent pain, 40% were managed by a repeat

MVD, 43% with medication alone, 10% with a glycerol rhizotomyand 7% with a radiofrequency rhizotomy.

Journal of Clinical Neuroscience (2005) 12(7), 787–789

DISCUSSION

Most studies have found a preponderance of females in patientswith trigeminal, ranging between 2:1 to 4:3.2–5 In our study a2:1 distribution was found. Our median age was 65. It has beenpreviously noted that 70% of patients with trigeminal neuralgiaare over 50 years of age.3

Two patients had multiple sclerosis, one of whom became painfree from the procedure and the other had no pain relief at all. Arecent publication suggests that up to 50% of patients with MSmay have relief from MVD.6 Broggi hypothesized that in MS adual cause for trigeminal neuralgia might be possible. He hypoth-esized that the action of vascular compression might be facilitatedby the underlying hyperexcitability of trigeminal pathways due toevolving demyelination.6

Success rates of MVD for trigeminal neuralgia have beenquoted as 75–80% in some prospective studies with a good butnot total relief in an additional 10%.7–9 In our study, 93% of pa-tients were pain free after MVD and a further 4% had some relief.This was, however, a largely retrospective chart review and ourmode of achieving information by telephone interview may haveunderestimated the level of morbidity and mortality. Informationwas not available for 110 of the 266 patients in this time period.We were able to ascertain that these patients were dischargedalive, however, by hospital policy, medical records are destroyedafter 10 years if the patient has not sought further medical atten-tion. This accounted for most of the missing data. It is possiblethese patients sought medical attention elsewhere in the event ofa complication or recurrence, however it seems more likely thatthese patients did not have problems and did not represent after

ª 2005 Published by Elsevier Ltd.

789Microvascular decompression for trigeminal neuralgia

treatment. Another problem was that as this is a disease of the el-derly, patients who had had MVD more than 15 years ago werenow dead from other causes and unable to be interviwed. This ac-counted for a significant number of missing cases.It has been previously reported that a prior destructive proce-

dure reduces the chance of pain relief at future procedures to43%.10,11 Our study did not agree with previous findings. Wefound that 94% of patients who had had a prior destructive proce-dure obtained pain relief with MVD. Only 6% of our patients withrecurrences had had a previous surgical procedure other thanMVD, compared with 12% of our patients who did not have arecurrence.Major pain recurrence is reported to occur at 3.5% annually and

in a study of patients followed for 8.5 years, 70% remained painfree.12 In our study, 74% of patients were pain free at 10 yearsand the greatest time for recurrence was within the first two years.In the first year after MVD, 5% had a recurrence and in the secondyear, 4%. This is similar to other publications.12

Several studies have reported the incidence of bilateral trigeminalneuralgia at presentation, which is estimated at between 1–5%.3,13,14 In our study, no patients had bilateral trigeminal neuralgiaat presentation, however of the 30% who had a recurrence of pain,over one third developed it on the opposite side. None of our patientswith recurrent pain on the opposite side had multiple sclerosis.In our study, 18% of recurrences of trigeminal neuralgia after

MVD were still not pain free despite further intervention. These18% were treated with combinations of treatments; 40% weretreated with medication alone, 33% with repeat MVD, 14% withglycerol rhizotomy and 13% by radiofrequency rhizotomy.Of those treated with repeat MVD (12 patients), 75% were pain

free. Several problems were noted at repeat operation. A secondbranch of the superior cerebellar artery which had not been previ-ously identified was found to now be causing compression, thenerve was trapped by adhesive scar tissue onto the tentorium orthe Teflon or plastic pledget had slipped out of position.Mortality after MVD in most studies is quoted as 0.22–2%, sen-

sory facial loss in 25%, major neurological morbidity in 1–10%,meningitis in 1%, deafness in 1%, sensory facial loss in 25%,hearing loss in 3%, diplopia in 4.3%, facial nerve paresis in1.6%, haemorrhage in 1%, infarction in 1% and pneumonia in0.6%.5,16,17 In our study there was zero mortality, 22% had facialnumbness, 7% sustained a stroke, 3% developed meningitis, 4%developed permanent hearing loss, 3% developed permanent dip-lopia, 1% permanent facial paresis and 1% medical complications.These appear compatible with previous reports. Our slightly high-er hearing loss may be explained by a change in technique in the1980s. Initially the classic Jannetta approach was used, in whichthe cerebellum is retracted posteriorly. Later, a more superior ap-proach was used. In this approach, less traction is applied onto theinternal auditory artery and cochlear nerve and theoretically, hear-ing loss should be less common. This appeared to be the trend inour study where hearing loss was reported more frequently after

ª 2005 Published by Elsevier Ltd.

MVD in the earlier part of the study period. This may explainour slightly higher overall rate of hearing loss.15,18

From this study it appears the most important outcome for pa-tients is becoming pain free. Major complications from MVD areuncommon and patients appear to tolerate well a minor permanentcomplication as long as they are pain free. Pain recurrence carriesa less satisfactory result from second treatment compared to re-sults at the first procedure.

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Journal of Clinical Neuroscience (2005) 12(7), 787–789