J Neurol Surg A Cent Eur Neurosurg 2023; 84(05): 470-476
DOI: 10.1055/a-1994-7956
Review Article

A Comparative Review of the Outcome Following MVD and PBC in Patients with Trigeminal Neuralgia

Yi Zhou*
1   Department of Neurosurgery, TaiHe Hospital, Hubei University of Medicine, Shiyan, Hubei, People's Republic of China
,
Ning-Ning Dou*
2   Department of Neurosurgery, XinHua Hospital, Shanghai JiaoTong University School of Medicine, Shanghai, People's Republic of China
,
Xue-Lai Liu
3   Department of Neurosurgery, LingYi Hospital of Traditional Chinese Medicine, Shandong, People's Republic of China
,
Hui Wang
1   Department of Neurosurgery, TaiHe Hospital, Hubei University of Medicine, Shiyan, Hubei, People's Republic of China
,
Jun Zhong
2   Department of Neurosurgery, XinHua Hospital, Shanghai JiaoTong University School of Medicine, Shanghai, People's Republic of China
› Author Affiliations

Funding None.
 

Abstract

Background This study aims to systematically review the treatment outcomes of percutaneous balloon compression (PBC) and microvascular decompression (MVD) in patients with trigeminal neuralgia.

Methods A systematic review in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guideline was performed using PubMed, Embase, and Cochrane Central Registry of Controlled Trials databases. Only those articles with more than 5 years' follow-up length were included in this investigation. To uniformly assess the postoperative outcome, we defined pain relief as totally pain free, while the postoperative hospitalization and last follow-up period were defined as early and long term, respectively. The facial numbness was quantified with Barrow Neurological Institute Pain Intensity Score (BNI).

Results After database searching and screening, 7,797 cases were finally included according to the criteria. The early pain relief rates were 94.1% (1,551/1,649) and 89.9% (4,962/5,482) following PBC and MVD (odds ratio [OR] = 0.603; p < 0.05), while the long-term rates were 58.1% (921/1,566) and 74.9% (4,549/6,074; OR = 2.089; p < 0.05), respectively. Although a significant higher facial numbness occurred in the PBC group in the early stage, it was mostly diminished 5 years later compared with the MVD group. At long-term follow-up, hypoacusis and facial palsy occurred more often in the MVD group (p < 0.05).

Conclusions Both MVD and PBC provide a satisfactory outcome for the patients in the long term. As a simple, safe, and reliable technique, PBC should be considered as a viable alternative.


Introduction

Although it is not life-threatening, patients with trigeminal neuralgia (TN) suffer from an intense pain.[1] According to the American Academy of Neurology (AAN), the European Federation of Neurological Societies (EFNS), and also other recent guidelines, carbamazepine (CBZ) and oxcarbazepine (OXC) are the first-line medical treatments. These drugs are highly effective with meaningful pain control in almost 90% of patients.[2] [3] However, clinical improvement is often offset by side effects and treatment withdrawal in 23% of patients. Surgery is generally undertaken only when standard doses of medications are not sufficient to control symptoms or if side effects prevent continued use. The surgical processes can be catalogued as etiological and symptomatic managements. As a unique etiological treatment, the success of microvascular decompression (MVD) depends upon the reversibility of dysfunction caused by arterial compression of the nerve root.[4] [5] [6] However, MVD may not work in those with idiopathic TN (no apparent cause of nerve disturbance can be found).[7] [8] Besides, not all the patients with classical TN are ready to accept the craniotomy. Therefore, those less invasive therapies, for example, Gamma Knife stereotactic radiosurgery, glycerol rhizotomy, and radiofrequency thermocoagulation as well as percutaneous balloon compression (PBC) have been still widely adopted.[9] [10] [11] [12] Due to low cost, simplicity, and the advantage of thorough compression of the ganglion, PBC has been popularized recently—especially for the elderly patients, those with comorbidities who are not good craniotomy candidates and those with recurrence following MVD.[13]

Unlike the other symptomatic treatments acting on the axons, PBC targets the gasserian ganglion (neuron soma). With the unrenewable nature of neurons, an appropriate compression may result in an unrecoverable lesion and give rise to a permanent pain relief. Theoretically, it is possible to damage more pain-sensing than other neurons if appropriate pressure is applied due to the difference in resilience of varied neurons.

In this investigation, we conducted a systematical review to compare the cure, recurrence, and complication rates between PBC and MVD. We were able to obtain evidence to support the hypothesis that proper compression of the trigeminal ganglion may lead to a long-term pain-free outcome without permanent dysesthesia.


Material and Methods

Database Searching

Electronic searches were performed using Ovid Embase, PubMed, and Cochrane Central Register of Controlled Trials (CCTR) from their dates of inception to June 2021. The diagnostic terms used were as follows: trigeminal neuralgia, tic douloureux, and facial neuralgia. They were combined with the following surgical terms: rhizotomy, balloon compression, microcompression, percutaneous compression and microvascular decompression.


Inclusion Criteria and Identified Studies

The primary inclusion criterion for this investigation was the average follow-up duration of the studies, which should be more than 5 years. The identified studies were read in their full texts and evaluated for quality using a criterion reported by Zakrzewska and Lopez,[14] which had been established by a panel of 11 neurosurgeons and 2 neurologists who were members of the advisory boards of the United States or United Kingdom TN associations ([Table 1]). Almost all patients underwent preoperative magnetic resonance (MR) examination. The possible neurovascular conflict (NCV) was investigated preoperatively by MR cranial nerve hydrographic imaging technique before MVD. In cases of studies reporting the same data or data involving more patients or longer follow-up monitoring, only the study with the largest patient number was used.

Table 1

Inclusion criteria

1. Study dealing with primary trigeminal neuralgia

2. Minimum of 30 patients treated in the whole series

3. Less than 10% of patients treated more than once with any procedure

4.Minimum of 5-year mean follow-up period

5. Diagnostic criteria stated

6. Definition of success presented

7. Definition of recurrence presented

8. Length of follow-up period with range and mean-median presented

9. Explicit definition of outcome measure used

10. Mortality rate stated

11. Report of perioperative complication

12. Report of postoperative complication

Note: The criterion of this table was a recommendation for outcome reporting for the surgical treatment of trigeminal neuralgia, established by a panel of 11 neurosurgeons and 2 neurologists, who were members of the advisory boards of the United States or United Kingdom trigeminal neuralgia associations.[14]



Outcome Evaluation

To properly assess the postoperative outcome, total relief from pain without any medication in the postoperative course was defined as pain relief, while recurrence of pain not adequately controlled by medication was defined as recurrence. Meanwhile, we defined the postoperative hospitalization period as early-term and a more than 5 years' follow-up period as long term, respectively. Furthermore, we regarded the complications that emerged within 6 months postoperatively as transient, while those that existed persistently during the whole follow-up period were regarded as permanent. In the selected articles, facial numbness was depicted as hypesthesia, paresthesia, and dysesthesia. In the study, we categorized the numbness with Barrow Neurological Institute Pain Intensity Score (BNI). BNI I is defined as no numbness, BNI II as moderate numbness that has no impact on daily life, BNI III as numbness that somewhat exerts an impact on daily life, and BNI IV as numbness that has a serious impact on daily life.[15]


Data Analysis

The following variables were recorded in a predesigned database: general information (author, year, surgery period, sample size, treatment success [before discharge and overall; [Table 2]], follow-up duration, and adverse events including facial numbness, hearing deficit, cerebrospinal fluid (CSF) leak, diminished corneal reflex, aseptic meningitis, and mortality). Statistical analysis was performed using the IBM SPSS 26 (IBM Analytics, Armonk, New York, United States) software, with a significance level of p < 0.05 for all tests. The two-sided chi-squared test or Fisher's exact test was used to compare proportions between groups of patients. Data were censored if there was no pain recurrence at the most recent follow-up.

Table 2

List of the included studies

Study

Country

Period

Technique

Mean FU (mo)

No. (male%)

Comp-Time (min)

Bederson et al[17]

United States

1969–1985

MVD

61

76 (30.2)

Lichtor et al[18]

United States

1980–1990

PBC

120

3–5

Sun et al[19]

Japan

1982–1992

MVD

80

61 (32.8)

Walchenbach et al[20]

Netherlands

1980–1990

MVD

77.3

19 (32.2)

Barker FN et al[21]

United States

1972–1991

MVD

74

479 (40)

Skirving et al[22]

Australia

1980–1999

PBC

128

496 (56.3)

2–5

Tyler-Kabara et al[23]

United States

1972–2000

MVD

125

883 (39)

Sindou et al[24]

France

1983–1999

MVD

86

Laghmari et al[25]

Morocco

1983–2004

PBC/MVD

72

41 (51.2)

5

Ferroli et al[26]

Italy

1997–2007

MVD

70

476 (–)

Günther et al[27]

Germany

1979–2001

MVD

90

362 (–)

Sarsam et al[28]

England

1982–2005

MVD

84

123 (38.5)

Oesman et al[29]

England

1983–2003

MVD

114

66 (42)

Chen et al[30]

China

2000–2010

PBC

120

63 (48.5)

2–3

Zhang et al[31]

China

2001–2011

MVD

67

56 (36)

Abdennebi et al[32]

Algeria

1985–2012

PBC

198

901 (47.2)

7

Sandel et al[33]

Norway

1999–2009

MVD

85

98 (40.3)

Masuoka et al[34]

Japan

2007–2012

MVD

62

50 (30)

Liu et al[35]

China

2009–2017

MVD

63

30 (30.3)

Abbreviations: Comp-Time, compression time; FU, follow-up; mo, month; MVD, microvascular decompression; No., patient number; PBC, percutaneous balloon compression.




Results

Study Identification

A total of 1,676 articles were systematically assessed (1,388, 258, and 30 refer to MVD, PBC, and both, respectively). According to the inclusion criteria, 1,033 were excluded following title and abstract screening and 502 studies were subjected to a full-text review.[16] Finally, 19 articles[17] [18] [19] [20] [21] [22] [23] [24] [25] [26] [27] [28] [29] [30] [31] [32] [33] [34] [35] consisting of 7,797 cases met the predetermined search criteria and were included in this study ([Fig. 1])

Zoom
Fig. 1 A flowchart regarding the literature search and study selection.

Outcomes

Pain Relief

The incidences of early pain relief were 94.1% (1,551/1,649) and 89.9% (4,962/5,482) following PBC and MVD, respectively (odds ratio [OR] = 0.603; 95% confidence interval [CI]: 0.482–0.754; p < 0.05). The long-term pain relief rates were 58.1% (921/1,566) and 74.9% (4,549/6,074; PBC vs. MVD; OR = 2.089; 95% CI = 1.860–2.346; p < 0.05; [Table 3]).

Table 3

Outcome comparison between PBC and MVD

Outcome

PBC

MVD

p value

Early pain relief

94.1% (1,551/1,649)

89.9% (4,962/5,482)

<0.05

Long-term pain relief

58.1% (921/1,566)

74.9% (4,549/6,074)

<0.05

Recurrence

39.2% (614/1,566)

18.9% (1,144/6,074)

<0.05

Abbreviations: MVD, microvascular decompression; PBC, percutaneous balloon compression.


Note: Values are presented as rate (number).



Recurrence

The recurrence rates within the entire follow-up period were 39.2% (614/1,566) and 18.9% (1,144/6,074) in the PBC and MVD groups, respectively (OR = 0.360; 95% CI = 0.319–0.406; p < 0.05; [Table 3]).


Complications

The most prominent difference in complications between the PBC and MVD groups were facial numbness. In the early stage following PBC and MCD, the facial numbness BNI II occurred in 83.3% (1,374/1,649) and 2.1% (103/4,908), BNI III in 11.2 and 0.3%, BNI IV in 2.4 and 0.5%, respectively. At the last follow-up, BNI II occurred in 1.9% (32/1,649) and 1.0% (26/4,908), BNI III in 1.0 and 0.2%, and BNI IV in 1.9 and 0.1%, respectively. Other transient complications included herpes, nerve palsy, infection, rhinorrhea and vertigo, and CSF fistula, which mainly occurred in MVD groups ([Table 4]). The other long-term complications, such as hypacusis and facial palsy, occurred more often in the MVD group ([Table 5]). The percentage of surgical mortality was 0.1% (1/1,649) and 0.1% (9/6,074) in the PBC and MVD groups, respectively.

Table 4

Comparison of transient complications between PBC and MVD

Transient complications

PBC (%)

MVD (%)

p value

Facial numbness

 BNI I

3.1

97.1

<0.05

 BNI II

83.3

2.1

<0.05

 BNI III

11.2

0.3

<0.05

 BNI IV

2.4

0.5

<0.05

Masticatory weakness

6.7

0.1

<0.05

Herpes

6.3

0.2

<0.05

Nerve palsies

1.3

2.7

>0.05

CSF fistula

0.2

2.0

<0.05

Infectious

0.1

0.7

>0.05

Vertigo

0.0

1.4

<0.05

Diminished corneal reflex

0.7

0.1

<0.05

Aseptic meningitis

0.1

22.4

<0.05

Abbreviations: BNI, Barrow Neurological Institute Pain Intensity Score; CSF, cerebrospinal fluid; MVD, microvascular decompression; PBC, percutaneous balloon compression.


Table 5

Comparison of permanent complications between PBC and MVD

Permanent complications

PBC (%)

MVD (%)

p value

Unilateral blindness

0.1

0.0

>0.05

Hearing loss

0.1

1.3

<0.05

Facial palsy

0.2

0.3

<0.05

Cerebral infarction

0.1

0.7

>0.05

Facial numbness

 BNI I

95.2

98.7

>0.05

 BNI II

1.9

1.0

<0.05

 BNI III

1.0

0.2

<0.05

 BNI IV

1.9

0.1

<0.05

Mortality

0.1

0.1

>0.05

Abbreviations: BNI, Barrow Neurological Institute Pain Intensity Score; MVD, microvascular decompression; PBC, percutaneous balloon compression.





Discussion

To date, results on the curative effect of MVD versus PBC for TN are inconsistent.[36] [37] Previous researches that have been conducted to compare MVD and PBC included inhad small sample sizes.[38] [39] This study systematically reviewed a long-term effect of PBC or MVD on treatment of TN. To objectively estimate the data collected from different studies, a uniform inclusion criterion is essential. In this investigation, a widely acceptable criterion, recommended by the Medical Advisory Board of the United States and United Kingdom Trigeminal Neuralgia Support Group, was adopted and 7,797 cases were included eventually.[14] Statistical analysis demonstrated that PBC gave rise to a significantly higher odds for early pain relief than MVD did. While a lower recurrence was found in MVD group, a relief rate close to 70% remained in the PBC group even 5 years later. The results implied that PBC could be a good alternative therapy compared with MVD.

Over the last decades, MVD has been regarded as an effective etiological treatment of classical TN, even in elderly patients,[40] [41] because of its high cure and low relapse rate as well as the character of a nondestructive surgical technique.[21] [28] [31] [42] The nerve can be compressed either by a vein or an artery or both somewhere along its intradural course. Sometimes, no compressing vessel can be found.[6] [10] [25] [41] [42] [43] To ensure cure, some surgeons perform an “MVD plus” surgery, decompression followed by a partial sensory rhizotomy.[6] [26] [44] [45] [46] This operation may lead to facial numbness postoperatively. In conclusion, MVD is not the perfect therapy for TN so far.

In addition to MVD, a variety of ablative procedures are available. They all work more or less at a cost of hemifacial numbness.[47] [48] Studies reported that radiofrequency thermal rhizotomy provided a similar initial pain relief rate as PBC.[49] [50] [51] [52] However, this procedure relies on the patient's cooperation to localize the target—an awake surgery leaves the patient a painful and terrified experience. In contrast to the immediate pain relief associated with these percutaneous lesion processes, the pain-relieving effect of Gamma Knife stereotactic radiosurgery takes 6 to 8 weeks to develop.[4] [53] [54] [55]

All destructive techniques except PBC target the axons,[56] [57] [58] which have higher rate of recovery, increasing the risk of recurrence.[59] [60] PBC evenly compresses the structures of the trigeminal ganglion.[61] [62] [63] The ganglion consist of neuron somata, which cannot regenerate once destroyed. Theoretically, an appropriate compression may selectively damage the pain-sensing neurons and preserve others as far as possible. Nevertheless, the usual explanation is that compression injures the medium and large myelinated nerve fibers and led to disruption of the ephaptic transmission of pain. Notably, activity in myelinated sensory axons is generally associated with the sense of touch and vibration, not pain.[64] [65] Injury of the myelinated nerve fiber is not closely related to pain relief. The overwhelming majority of studies reported that hemifacial numbness after PBC was usually transient and resolved spontaneously.[66] Although no trigger is eliminated in PBC, it virtually “powers off” the trigeminal nerve for the generation and conduction of action potentials depend on the energy support provide by the neurons. That is probably the reason why PBC leads to an immediately higher pain relief rate than MVD does. Therefore, we believe that if the gasserian ganglion have been compressed efficiently by a balloon inflated exactly inside Meckel's cave instead of in its interlay, a higher long-term efficacy can be expected.[67] [68] [69]

Regardless of the unavoidable facial numbness, the postoperative course was more even and comfortable in patients who underwent PBC than MVD.[70] Furthermore, the numbness rate can be reduced by a proper control of the compression time.[30] [71] Lichtor and Mullan compared their first 60 patients with 5- to 7-minute compressions to the rest of the 40 patients with 1-minute compressions and found that the efficiency was the same and facial numbness rate was lower in the second group.[18] Evidently, there is a delicate balance between pain recurrence and numbness.[72] [73] Referring to the literature, we believe a 1-minute compression might be adequate to achieve a pain-free outcome without apparent facial discomfort.[18] [74] [75]

Several limitations need to be considered. Although thousands of cases were included, they were drawn from different centers with diverse evaluation scales. Especially concerning numbness, it was delineated as hypesthesia, paresthesia, or dysesthesia in various studies. For standardization, we employed the BNI score to quantify the numbness in this investigation.


Conclusions

MVD could not cure all the patients, especially not those without an obvious compressing artery. In contrast, PBC may relieve TN symptoms in most cases as long as the trigeminal ganglion has been effectively compressed. As a simple, convenient, safe, and reliable alternative, PBC should be considered as a viable alternative.



Conflict of Interest

None declared.

Author Contributions

J.Z. contributed to the study conception and design. Material preparation, data collection, and analysis were performed by N.N.D., X.L.L., Y.Z. and H.W. The first draft of the manuscript was written by Y.Z., and all the authors commented on previous versions of the manuscript. All the authors read and approved the final manuscript.


* Drs Dou and Zhou contributed equally to this study.



Address for correspondence

Jun Zhong, MD, PhD
Department of Neurosurgery, XinHua Hospital, Shanghai JiaoTong University School of Medicine
Shanghai 200092
People's Republic of China   

Publication History

Received: 03 January 2022

Accepted: 05 December 2022

Accepted Manuscript online:
08 December 2022

Article published online:
11 May 2023

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Zoom
Fig. 1 A flowchart regarding the literature search and study selection.