Tuesday, 18 December 2012

Facial pain or trigeminal neuralgia

#MSBlog: the majority of MSers with intractable facial pain or trigeminal neuralgia respond to treatment

Tuleasca et al. Patterns of pain-free response in 497 cases of classic trigeminal neuralgia treated with Gamma Knife surgery and followed up for least 1 year. J Neurosurg. 2012 Dec;117 Suppl:181-8. doi: 10.3171/2012.8.GKS121015.

Object: The goal of this study was to establish whether clear patterns of initial pain freedom could be identified when treating MSers with classic trigeminal neuralgia (TN) by using Gamma Knife surgery (GKS). The authors compared hypesthesia and pain recurrence rates to see if statistically significant differences could be found.

Methods: Between July 1992 and November 2010, 737 patients presenting with TN underwent GKS and prospective evaluation at Timone University Hospital in Marseille, France. In this study the authors analyzed the cases of 497 of these patients, who participated in follow-up longer than 1 year, did not have megadolichobasilar artery (large kinky artery that presses on the nerve) - or multiple sclerosis-related TN, and underwent GKS only once; in other words, the focus was on cases of classic TN with a single radiosurgical treatment. Radiosurgery was performed with a Leksell Gamma Knife (model B, C, or Perfexion) Using empirical methods and assisted by a chart with clear cut-off periods of pain free distribution, the authors were able to divide MSers who experienced freedom from pain into 3 separate groups: patients who became pain free within the first 48 hours post-GKS; those who became pain free between 48 hours and 30 days post-GKS; and those who became pain free more than 30 days after GKS. 

"Gamma Knife surgery (GKS) is a method that is able to deliver very high doses of gamma radiation to a very small area of the brain. It reduces surrounding tissue damage that occurs with standard radiotherapy."

Results: The median age in the 497 patients was 68.3 years (range 28.1-93.2 years). The median follow-up period was 43.75 months (range 12-174.41 months). Four hundred fifty-four patients (91.34%) were initially pain free within a median time of 10 days (range 1-459 days) after GKS. One hundred sixty-nine patients (37.2%) became pain free within the first 48 hours (Group PF(≤ 48 hours)), 194 patients (42.8%) between posttreatment Day 3 and Day 30 (Group PF((>48 hours, ≤ 30 days))), and 91 patients (20%) after 30 days post-GKS (Group PF(>30 days)). Differences in postoperative hypesthesia were found: in Group PF(≤ 48 hours) 18 patients (13.7%) developed postoperative hypesthesia (numbness), compared with 30 patients (19%) in Group PF((>48 hours, ≤ 30 days)) and 22 patients (30.6%) in Group PF(>30 days) (p = 0.014). One hundred fifty-seven patients (34.4%) who initially became free from pain experienced a recurrence of pain with a median delay of 24 months (range 0.62-150.06 months). There were no statistically significant differences between the patient groups with respect to pain recurrence: 66 patients (39%) in Group PF(≤ 48 hours) experienced pain recurrence, compared with 71 patients (36.6%) in Group PF((>48 hours, ≤ 30 days)) and 27 patients (29.7%) in Group PF(>30 days) (p = 0.515).

Conclusions:  A substantial number of patients (169 cases, 37.2%) became pain free within the first 48 hours. The rate of hypesthesia or numbness was higher in patients who became pain free more than 30 days after GKS, with a statistically significant difference between patient groups (p = 0.014).

Mathieu et al. Comparative study of Gamma Knife surgery and percutaneous retrogasserian glycerol rhizotomy for trigeminal neuralgia in patients with multiple sclerosis. J Neurosurg. 2012 Dec;117 Suppl:175-80. doi: 10.3171/2012.6.GKS12987.

Objective: Among MSers there is a high incidence of trigeminal neuralgia (TN), and outcomes after treatment seem inferior to those in patients suffering from idiopathic TN. The goal of this study was to evaluate clinical outcomes in patients with MS-related TN after Gamma Knife surgery (GKS) and compare them with those obtained using percutaneous retrogasserian glycerol rhizotomy (PRGR). 

"Percutaneous retrogasserian glycerol rhizotomy (PRGR) is a technique that involves injecting glycerol into the ganglion of the nerve. The glycerol causes and inflammatory reaction that destroys the nerve and hopefully reduces the pain."

Methods: The authors retrospectively reviewed the charts of 45 MSers with MS-related TN. The first procedure undertaken was GKS in 27 Msers and PRGR in 18 MSers. Pain had been present for a median of 60 months (range 12-276 months) in MSers who underwent GKS and 48 months (range 12-240 months) in MSers who underwent PRGR. The following outcome measures were assessed in both groups of MSers: pain relief (using the Barrow Neurological Institute [BNI] Pain Scale), procedure-related morbidity, time to pain relief and recurrence, and subsequent procedures that were performed. 

Results: The median duration of follow-up was 39 months (range 13-69 months) in the GKS group and 38 months (range 2-75 months) in the PRGR group. Reasonable pain control (BNI Pain Scale Scores I-IIIb) was noted in 22 MSers (81.5%) who underwent GKS and in 18 MSers (100%) who underwent PRGR. For MSers who underwent GKS, the median time to pain relief was 6 months; for those who underwent PRGR, pain relief was immediate. In the GKS group 12 MSers required subsequent procedures (3 MSers for absence of response and 9 MSers for pain recurrence), whereas in the PRGR group 6 MSers required subsequent procedures (all for pain recurrence). As of the last follow-up, complete or reasonable pain control was finally achieved in 23 MSers (85.2%) in the GKS group and in 16 MSers (88.9%) in the PRGR group. The morbidity rate was 22.2% in the GKS group (all due to sensory loss and paresthesia) and 66.7% in the PRGR group (mostly hypalgesia, with 2 MSers having corneal reflex loss and 1 MSers suffered from meningitis).

Conclusions:  Both GKS and PRGR are satisfactory strategies for treating MS-related TN. Gamma Knife surgery has a lower rate of sensory and overall morbidity than PRGR, but requires a delay before pain relief occurs. The authors propose that MSers with extreme pain in need of fast relief should undergo PRGR. For other MSers , both management strategies can lead to satisfactory pain relief, and the choice should be made based on patient preference and expectations.

"These two studies demonstrate that the majority of MSers with refractory trigeminal neuralgia respond to pain. GKS is not freely available and is very expensive. It is reassuring to note that PRGR works as well, albeit with a slightly higher complication rate. A problem I find with treating TG with medication is that the medication can be very sedating and surgical intervention is therefore more appropriate."

"Thankfully, most of you will not have experienced trigeminal neuralgia. If you have you will know how severe and incapacitating the pain can be."

Additional reading: trigeminal neuralgia, gamma knife surgery

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