What are the reported outcomes for trigeminal neuralgia (TN) surgery?

Updated: Sep 30, 2019
  • Author: Kim J Burchiel, MD, FACS; Chief Editor: Brian H Kopell, MD  more...
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Answer

Answer

Accurate data on surgical outcome are still difficult to obtain. Most surgical series do not meet modern criteria for evidence-based medicine. Recently, an evidence-based approach has been applied to both the diagnosis of trigeminal neuralgia (TN) and its surgical management. These results were published in Neurology in August 2008 and can be viewed at Medscape.

The challenges of the field are exemplified by a paper published by Zakrzewska and Lopez, who assessed the quality of 222 reports of surgical management of TN and found only 3 randomized controlled trials (RCTs) on peripheral techniques. [23] The vast majority of the evidence derived from case series reports (class 3 evidence), and a very high proportion was of poor quality.

The difficulties center on the following important issues:

  • Lack of clear diagnostic criteria and baseline assessments

  • Poor methodology - Low numbers, short follow-up period, high percentage lost to follow-up, mixture of cases (eg, previous surgery, including repeated treatments)

  • Lack of Kaplan-Meier assessment of pain relief, poorly defined outcome measures (eg, partial success), incomplete reporting of all complications, and no quality-of-life evaluations

  • Lack of independent evaluation

Certain principles seem to transcend even the relatively poor outcomes studies performed thus far Seemingly, the longer the duration of symptoms, the poorer the chances of success. Of all the procedures, microvascular decompression (MVD) carries the lowest rate of facial dysesthesia (0.3%). Compared with the percutaneous procedures, MVD rarely causes facial numbness (rate, 0.15%). In addition, it is the preferred procedure in younger patients who desire no sensory deficit. It is also the treatment most likely to yield sustained postoperative pain relief.

One study found that 70% of patients had excellent results (defined as a cure or significant pain relief) 10 years after the procedure. [24] Possible reasons for failure include new vascular compression from scarred implants or other sources, but these are rarely identified during posterior fossa reexploration for failed MVD. After an initial 10% risk of recurrence of TN within 1 year after MVD, the risk of pain recurrence is about 3.5% every succeeding year. [25] The reasons for this recurrence are not clear.

In a 1999 study, cerebellar injuries and hearing loss occurred in fewer than 1% of the patients, and cerebrospinal fluid (CSF) leakage occurred in 1.85%. [26] As expected, these rates were inversely proportional to the total number of procedures performed.

Burchiel reported that 90% of patients are pain free after any of the operations mentioned. [27] Those in whom the first percutaneous procedure fails may undergo a repeat procedure, which usually provides relief. Sweet reported that pain-free intervals last 1.5-2 years after percutaneous retrogasserian glycerol rhizotomy (PRGR) and percutaneous balloon microcompression (PBM) and last 3-4 years after percutaneous radiofrequency trigeminal gangliolysis (PRTG). For MVD, 15 years of relief is typical.


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