Botulinum Toxin Type A for refractory trigeminal neuralgia in older patients: a better therapeutic effect

Figures & data

Figure 1 Schematic showing injection sites for BTX-A. The shading shows the distribution of pain and the filled circles represent BTX-A injection sites. Reproduced from Wu CJ, Lian YJ, Zheng YK, et al, Botulinum toxin type a for the treatment of trigeminal neuralgia: results from a randomized, double-blind, placebo-controlled trial, Cephalalgia (32(6)) pp. 443–450. Copyright © [2012] (SAGE Publications).¹⁷ 

Table 1 The Patient Global Impression of Change (PGIC) Scale

PGIC Scale	Description
1	Very much improved
2	Much improved
3	Minimally improved
4	No change
5	Minimally worse
6	Much worse
7	Very much worse

Figure 2 Flow diagram.

Table 2 Patient demographics

Demographics	Characteristics	Range or percentage
Gender (male:female)	44:60	57.69% (female)
Side of involvement (right:left)	71:33	68.26% (rignt)
Age (years)	59.21±12.05	33–93
Duration of diseases (months)	76.23±56.18	12–300
Average daily pain score	8.40±1.50	6–10
Average frequency of TN attacks per day	24.90±27.70	4–120
Dosage	59.62±21.69	25–120
The nerve branch involved (n)
V1 only	9	8.7%
V2 only	37	35.6%
V3 only	29	27.9%
V1+V2	9	8.7%
V1+V3	1	1.0%
V2+V3	16	15.4%
V1+V2+V3	3	2.9%
Previous operation (n)
Prior MVD	10	9.6%
Prior radiofrequency ablation	5	4.8%
≧2 treatments	0

Abbreviations: TN, trigeminal neuralgia; V1, trigeminal nerve division 1; V2, trigeminal nerve division 2; V3, trigeminal nerve division 3; MVD, microvascular decompression.

Table 3 Factors of outcomes after BTX-A for trigeminal neuralgia

	Univariate analysis		Multivariate analysis		Multivariate analysis
	P-value	Odds ratio (95% CI)	P-value	OR (95% CI)	P-value	OR (95% CI)
Duration of diseases	0.68	1.625 (0.911–1.153)
Gender	0.92	0.946 (0.329–2.717)
Dosage	0.92	1.032 (0.566–1.884)
Average Frequency of TN attacks per day	0.76	1.003 (0.983–1.023)
Average daily pain score		1.07 (0.75–1.525)
Side of involvement	0.14	2.204 (0.764–6.36)
The nerve branch involved
V1	0.13	5.091 (0.637–40.714)
V2	0.84	0.893 (0.302–2.641)
V3	0.59	1.33 (0.465–3.823)
Toothache	0.15	0.455 (0.154–1.343)	0.15	0.426 (0.132–1.374)	0.13	0.405 (0.126–1.303)
Side effects		3.33 (0.41–27.098)	0.16	4.487 (0.54–44.197)	0.12	5.684 (0.628–51.445)
Hypertension	0.51	1.69 (0.351–8.14)
Diabetes	0.44	0.376 (0.032–4.403)
Dyslipidemia	0.64	0.571 (0.056–5.847)
Body Mass Index (BMI)	0.32	0.703 (0.354–1.397)
Age	0.03	1.720 (1.063–2.282)
<40 yr vs ≥40 yr	0.82	1.297 (0.136–12.375)
<50 yr vs ≥50 yr		3.66(1.231–10.885)	0.03	3.403 (1.104–10.489)
<60 yr vs ≥60 yr	0.04	3.482 (1.052–11.526)			0.05	3.506 (1.013–11.928)

Abbreviations: yr, year; V1, trigeminal nerve division 1; V2, trigeminal nerve division 2; V3, trigeminal nerve division 3.

Figure 3 TN pain outcome after BTX-A in patients under50 compared to patients 50 and over. (A) Patients in the older age group had a significantly greater improvement in average daily pain score following BTX-A treatment. (B) There was a significantly greater proportion of patients in the older age group with PGICscale1-2.

Table 5 Comparison of demographics and outcomes in trigeminal neuralgia patients with <50 years vs ≥50 years

Variable	<50 years group	≥50 years group	P-value
Age (years)	43.04±4.09	64.33±8.73	0.000^c
Gender (% women)	64	55.67	0.464^a
Side of involvement (% right)	60	70.89	0.308^a
Duration of diseases (months)	61.36±40.49	80.94±59.75	0.218^c
The nerve branch involved (n)
V1 (%)	12	13.9	0.806^b
V2 (%)	56	54.4	0.891^a
V3 (%)	40	62.02	0.053^a
Time to take effect, d	11.76±11.49	10.05±6.43	0.682^c
Time to peak efficacy, d	32.29±16.01	34±20.2	0.974^c
Time of pain recurrence, m	5.67±2.84	5.69±3.01	0.876^c
Time before facial asymmetry, d	14.50±10.85	11.77±9.87	0.719^c
Duration of facial asymmetry, d	54.25±44.12	40.00±25.54	0.530^c

Notes: ^aChi-square test, ^bcontinuity corrected Chi-square test, ^cWilcoxon rank sum test.

Abbreviations: d, day; m, month; a Chi-square test, b continuity corrected Chi-square test, c Wilcoxon rank sum test.

Table 4 Outcomes among different age groups of patients who underwent BTX-A for trigeminal neuralgia

	<40 years	40–50 years	50–60 years	≥60 years
Patients, n	5	20	30	49
Ineffectiveness	1	7	5	4
Effectiveness	2	2	9	12
Significant effectiveness	1	5	4	11
Complete pain relief	1	6	12	22
Time to take effect, d	10.75±11.84	12.07±11.85	9.54±8.04	10.33±5.60
Time to peak efficacy, d	41.25±18.41	29.53±14.90	35.76±17.48	33.02±21.36
Initial treatment success, n (%)	4 (80%)	13 (65%)	25 (83.3%)	45 (91.83%)
Time of pain recurrence, m	6.25±1.71	5.49±3.14	5.75±2.27	5.67±3.23
Side effect, n	2	2	7	6
Time before facial asymmetry, d	7–14	7–30	7–42	7–21
Duration of facial asymmetry, d	31–39	27–120	25–120	21–52

Abbreviations: d, day; m, month.

Wu CJ, Lian YJ, Zheng YK, et al. Botulinum Toxin Type A for the treatment of trigeminal neuralgia: results from a randomized, double-blind, placebo-controlled trial. Cephalalgia. 2012;32(6):443–450. doi:10.1177/033310241244172122492424

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