Surgical Results of Microvascular Decompression ...

ORIGINAL ARTICLE Neurol Med Chir (Tokyo) 53, 360¿364, 2013

Surgical Results of Microvascular Decompression Procedures and Patient's Postoperative Quality of Life: Review of 139 Cases Keita SHIBAHASHI,1 Akio MORITA,1 and Toshikazu KIMURA1 1Department

of Neurosurgery, NTT Medical Center Tokyo, Tokyo

Abstract Microvascular decompression (MVD) is effective for the relief of symptoms, but little is known about the impact of the MVD procedure on patient's quality of life (QoL) or which QoL factors are important. The surgical results of MVD and the impact of this procedure were evaluated on patient's QoL in 139 patients, 74 with hemifacial spasm (HFS) and 65 with trigeminal neuralgia (TN), who underwent MVD between 2004 and 2011 using the 36-Item Short Form Health Survey questionnaire. Symptoms had resolved in approximately 95% of patients after MVD. The QoL questionnaire was completed by 54 HFS patients and 38 TN patients. Although long-term QoL scores for both groups were comparable to the average national value, scores related to physical role, emotional role, and social function were significantly lower for patients within 12 months of receiving MVD for HFS, compared with the reference scores. Symptomatic improvements and complications were correlated with the QoL scores related to the social function domain for patients with HFS. No other significant relationships were observed between any of the factors or scores in any of the respective domains or periods. Subjective symptoms were the main self-reported causes of delayed recovery of QoL domains. Some QoL domains take a long time to recover and postoperative subjective symptoms might be major causes in addition to delayed relief of symptoms. Key words:

microvascular decompression,

quality of life

Introduction

related to QoL after the procedure.

Materials and Methods

The technique of microvascular decompression (MVD) was first described by Dandy in 1934 and was later popularized by Jannetta in the 1970s.6,7) Since then, considerable efforts have been made to improve MVD surgical outcomes, including symptomatic relief and complication avoidance. However, few advances have been made since the 1990s.3,9,11,12,14) To improve the surgical technique further, different aspects of surgical outcome should be addressed. The main purpose of MVD is to improve the patient's quality of life (QoL) through surgical intervention. However, little is known about the patient's perioperative QoL or which QoL factors are important. The present study analyzed clinical outcomes and QoL measures in patients who underwent MVD for hemifacial spasm (HFS) and trigeminal neuralgia (TN) at our institution and assessed the factors Received 2012

October 6, 2012;

Accepted

The surgical results were analyzed of MVD procedures for the treatment of HFS and TN performed at our institution between 2004 and 2011. The results were classified according to Kondo's criteria.8) Mailin 36-Item Short Form Health Survey (SF-36) questionnaires were used to assess patient's QoL. The patients were grouped according to postoperative time (0–12 months and over 12 months), and the 95% confidence intervals (CIs) of the mean scores for each group were compared with normal reference scores. For patients with QoL scores that were lower than those of the normal population, an additional interview was conducted using a mail-in questionnaire to specifically inquire about the causes of their low QoL related to daily activities. To survey the QoL, the Japanese version of the SF-36 questionnaire (i-Hope international, Kyoto, http://www.i-hope.jp/ and Medical Outcome Trust, Hanover, New Hampshire, USA, http://www.

December 11,

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Impact of MVD on QoL outcomes-trust.org/) was used. The SF-36 has been demonstrated to be an effective tool for assessing health-related QoL in the Japanese population. This questionnaire addresses the following eight domains: physical function, role physical (RP), role emotional (RE), social function (SF), bodily pain, vitality, mental health, and general health. Reference scores were obtained from an average Japanese population sample.4) The 95% CI of the score for each domain of SF-36 was calculated. Statistically significant change was defined as this range not including the national standard value (SV). To identify factors correlated with postoperative QoL, multiple linear regression analyses included symptomatic improvement, complication severity, postoperative duration, age, sex, operative duration, amount of bleeding for each disease, and period. These analyses were performed using SPSS software (SPSSTM; SPSS Inc., Chicago, Illinois, USA) and p º 0.05 was considered as statistically significant. Student's t-test was used to compare the baseline characteristics between HFS and TN.

Results Data were acquired from 139 patients. Of these, 74 patients were treated for HFS (35% male and 65% female, mean age 51.9 years) and 65 patients were treated for TN (49% male and 51% female, mean age 58.8 years). The average duration of the follow-up period was 17 months for HFS patients and 28 months for TN patients. There were no significant differences in operative duration (HFS: 218 min, TN: 221 min) or amount of bleeding between the two procedures. Following MVD surgery for HFS, 60 patients (81%) were spasm-free, 12 patients (16%) experienced partial improvement, and 2 patients (3%) showed no change. Two patients experienced only temporary relief with recurrences. Approximately 25% of the spasm-free cases achieved this outcome by more than 1 month after surgery; 1 patient was spasm-free after 8 months, another patient was spasm-free after 12 months, and the other patients were spasm-free in less than 6 months (Table 1). After the treatment for TN, 58 patients (89%) became free of pain, 3 patients (5%) experienced relief, 2 patients (3%) experienced no change in their level of pain, and 2 patients (3%) experienced only temporary relief with recurrences. In contrast to patients with HFS, almost all (96%) of the TN pain-free cases were achieved within 7 days, and only 1 patient reported pain lasting for more than one month (Table 2). The duration of symptom recovery was

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Table 1 Surgical outcome of microvascular decompression for 74 patients with hemifacial spasm Surgical outcome Symptomatic relief* E-0 E-1 E-2 E-3 Timing of relief of E-0 cases Ã7 days 8–30 days 30–180 days À180 days Complication** C-0 C-1 C-2 Overall outcome*** T-0 T-1 T-2 T-3 ÆT-4

No. of cases 60 8 4 2

(81%) (11%) (5%) (3%)

42 3 13 2

(70%) (5%) (22%) (3%)

67 (91%) 7 (9%) 0 (0%) 53 15 4 2 0

(72%) (20%) (5%) (3%) (0%)

Assessment of surgical outcome used the classification by Kondo et al.8) *Evaluation of postoperative grade of involuntary movement (E): E-0, complete disappearance of spasm; E-1, occasional slight spasm; E-2, moderate spasm, apparently persisting; E-3, not cured. **Evaluation of postoperative complications (C): C-0, no or only slight possible cranial nerve dysfunction; C-1, slight cranial nerve or cerebellar dysfunction, not bothersome for daily life; C-2, both subjective and objective cranial nerve or cerebellar dysfunction, problematic for daily life. ***Total evaluation grade of the results (T) determined as the sum of the E and C grades: T-0, excellent; T-1, good; T-2, fair; T-3 to T-5, poor.

significantly shorter for TN than for HFS (p º 0.005). Completed QoL questionnaires were obtained from 54 (73%) HFS patients and 38 (58%) TN patients. For the analysis, these patients were grouped according to postoperative duration (0–12 months and more than 12 months). Time interval between the surgery and QoL assessment is summarized in Table 3. The 95% CI ranges were lower than the national SVs for RP (95% CI: 67.7–87.7, SV: 88.6), RE (95% CI: 65.7–86.4, SV: 87.1), and SF (95% CI: 67.6–85.5, SV: 86.5) scores for the early group of HFS. SV was included in the 95% CI ranges for other domains (Fig. 1). On the other hand, there were no statistically significant differences between the TN patients in comparison to the national SVs (Fig. 2). We found that the RP, RE, and SF scores were significantly lower for HFS patients within 12 months

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Table 2 Surgical outcome of microvascular decompression for 65 patients with trigeminal neuralgia Surgical outcome

No. of cases

Symptomatic relief* E-0 E-1 E-2 E-3 Timing of relief of E-0 cases Ã7 days 8–30 days 30–180 days À180 days Complication** C-0 C-1 C-2 Overall outcome*** T-0 T-1 T-2 T-3 ÆT-4

58 3 2 2

(89%) (5%) (3%) (3%)

56 1 1 0

(96%) (2%) (2%) (0%)

60 (92%) 5 (8%) 0 (0%) 53 8 2 2 0

(82%) (12%) (3%) (3%) (0%)

Assessment of surgical outcome used the classification by Kondo et al.8) *Evaluation of postoperative pain (E): E-0, completely pain-free; E-1, occasional slight pain, self-controllable without medication; E-2, moderate pain, controllable by medication; E-3, persistent pain, not controllable by medication, not cured. **Evaluation of postoperative complications (C): C-0, no or only slight possible cranial nerve dysfunction; C-1, slight cranial nerve or cerebellar dysfunction, not bothersome for daily life; C-2, both subjective and objective cranial nerve or cerebellar dysfunction, problematic for daily life. ***Total evaluation grade of the results (T) determined as the sum of the E and C grades: T-0, excellent; T-1, good; T-2, fair; T-3 to T-5, poor.

Fig. 1 Quality of life after microvascular decompression for hemifacial spasm. The squares and triangles represent the mean scores for the eight SF-36 domains in patients with hemifacial spasm who underwent surgery within 12 months and more than 12 months before, respectively. The columns show the national standard values (SVs). The 95% confidence interval (CI) range of scores is shown as the vertical line, and was significantly lower in 0–12 months group than the SVs in the RP, RE, and SF domains. There were no significant differences between the score and SV in other domains or periods. BP: bodily pain, GH: general health, MH mental health, PF: physical function, RE: role emotional, RP: role physical, SF: social function, VT: vitality.

Table 3 Time intervals between surgery and quality of life assessment Time interval (mos) Group 0–12 mos HFS 0–12 mos TN À12 mos HFS À12 mos TN

p Value Range

Mean

Median

1–12 5–12 14–72 13–60

7.1 8.5 37.5 37.1

8 8.5 33.5 36

0.40 0.92

There were no significant differences between hemifacial spasm (HFS) and trigeminal neuralgia (TN) in the early or late groups.

Fig. 2 Quality of life after microvascular decompression for trigeminal neuralgia. The squares and triangles represent the mean scores for the eight SF-36 domains in patients with trigeminal neuralgia who underwent surgery within 12 months and more than 12 months before, respectively. The columns show the national standard values (SVs). The 95% confidence interval (CI) range of scores is shown as the vertical line. There were no significant differences between the score and SV in any domains or periods. BP: bodily pain, GH: general health, MH mental health, PF: physical function, RE: role emotional, RP: role physical, SF: social function, VT: vitality.


Impact of MVD on QoL Table 4 Factors self-reported as the reasons for low scores in specific domains of quality of life within 12 months after receiving microvascular decompression for hemifacial spasm Factor Wound pain* Headache** Dizziness Tinnitus Vertigo Cosmetic deformity Fatigue

Role physical

Social function

Role emotional

4 1 1 2 1 1

1 3 2

1 1 1

*Pain localizes at the surface of surgical site. **Diffuse pain or heaviness of the head.

after MVD in comparison to the reference scores. For patients more than 12 months after the MVD, the scores for each domain recovered to levels comparable to those of the standard reference population. For the results regarding the SF domain for HFS patients, surgical outcome was significantly correlated with the QoL score (symptomatic improvement, p ＝ 0.01; complication severity, p ＝ 0.019; overall outcome, p ＝ 0.028) in the multiple linear regression analysis. However, this trend was not observed for other domains or for TN patients. Additional factors (age, sex, operative duration, or amount of bleeding) were not shown to be significantly correlated with patient's QoL. For this additional survey, responses were obtained in 10 cases pertaining to the RP domain, in 6 cases for the SF domain, and in 3 cases for the RE domain. The results are shown in Table 4. Subjective symptoms such as wound pain, headache, dizziness, vertigo, and tinnitus were reported to be the main reasons for low QoL.

Discussion Even with technical advances in microsurgical and monitoring techniques, and neurophysiological understanding, the surgical outcome of MVD has reached a plateau. Although the surgical outcomes of MVD in our institution are comparable to those of previous studies, and the majority of the patients enjoyed symptomatic relief, recovery of postoperative QoL in some cases required quite long times. The QoL assessment confirmed good scores for each domain in patients more than one year after surgery. However, the RP, RE, and SF domain scores for HFS patients were significantly lower within one year af-


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ter surgery, although this early low score was not observed in any domains of QoL of TN patients. Considering the characteristic of these domains, we considered that delayed relief of symptoms was the major factor to impede QoL recovery. On the other hand, delayed symptomatic relief was only observed in 25% of patients, and all symptomatic relief occurred within 6 months for HFS patients, so that only the prolonged symptom seems to be unreasonable as an explanation of delayed QoL recovery. In fact, except for the SF domain in HFS patients, no significant correlations were observed between symptomatic relief and QoL. Although our sample size was a possible cause, the reason that no correlation was observed in domains other than SF for HFS is unclear. To identify any factors causing delayed QoL recovery, we directly questioned patients who complained of low QoL after surgery. According to the results, we identified subjective symptoms that were stated as the cause of low QoL by patients. The patients suggested that these subjective symptoms are one potential cause for the delayed QoL recovery, even though we cannot draw conclusions based on our series because these complaints are quite common and our additional questionnaire was directed at only low QoL patients without matching. Subjective symptoms like pain, dizziness, and fatigue have not been scored as postoperative complications, but these factors may be important to explain the delayed QoL recovery. Similar impact of these subjective factors on QoL was recently described for patients who received cerebellopontine angle surgery.1,5,10) Delayed QoL recovery was also reported in patients receiving surgery for unruptured cerebral aneurysms.13) This study found that the increase in QoL scores associated with social function and physical or emotional limitation after surgery was markedly delayed, and that these factors took more than one year to normalize. By comparing surgical outcomes to those of endovascular treatment, invasive surgical procedures were identified as one potential cause for the delayed QoL recovery.2) Previous and current analyses of surgical outcome have usually focused on objective outcomes, but QoL analysis including our series showed some subjective symptoms may be important in postoperative recovery. Subjective symptoms should be added as observational targets and statistical analyses in future studies. We need to reaffirm the significance of QoL-oriented assessments including MVD procedures. Recovery from surgery may be facilitated through the identification of factors that influence early QoL following any given procedure.

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Acknowledgments 8)

We thank Drs. Chikayuki Ochiai, Tetsuro Sameshima, and Atsuya Akabane, NTT Medical Center Tokyo for their cooperation.

Conflicts of Interest Disclosure The authors have no personal financial or institutional interest in any of the drugs, materials, or devices in the article. All authors who are members of The Japan Neurosurgical Society (JNS) have registered online Self-reported COI Disclosure Statement Forms through the website for JNS members.

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Address reprint requests to: Keita Shibahashi, MD, Department of Neurosurgery, NTT Medical Center Tokyo, 5–9–22 Higashi-Gotanda, Shinagawa–ku, Tokyo 141–8625, Japan. e-mail: kshibahashi＠yahoo.co.jp
