The retrogasserian zone versus dorsal root entry zone: comparison of two targeting techniques of gamma knife radiosurgery for trigeminal neuralgia.
BACKGROUND
We performed a comparative study of the retrogasserian zone (RGZ) with the dorsal root entry zone (DREZ) target to determine effective gamma knife radiosurgery (GKRS) technique in patients with medically refractory trigeminal neuralgia (TN).


METHODS
We retrospectively reviewed the records of 39 patients with refractory TN undergoing GKRS between April 2005 and October 2008. Until October 2007, DREZ was used as the primary target point. Since November 2007, RGZ has been targeted, located anterior to DREZ. The pain outcome of patient, pain recurrence, and treatment-related complications were evaluated.


RESULTS
Using the Barrow Neurologic Index (BNI) pain score, 15 (93.8%) RGZ and 20 (87.0%) DREZ cases achieved treatment success (BNI pain score I-IIIb) (p = 0.631). Seven (43.8%) RGZ and four (17.4%) DREZ patients reported complete pain relief without medications (BNI pain score I). The time to a response after the GKRS was significantly shorter in the RGZ group (mean 4.1 weeks) than in the DREZ group (mean 6.4 weeks) (p = 0.044). The total complication rate (25.0%) in the RGZ group was similar to the DREZ group (26.1%); however, frequency of bothersome facial numbness and dry eye syndrome was lower in the RGZ group (0%, 0%) compared to the DREZ group (13.1%, 8.7%) (p = 0.255 and 0.503).


CONCLUSIONS
The RGZ targeting technique in the GKRS for TN had a better treatment success, with fewer bothersome complications compared to the DREZ target.
Park
Seong-Hyun
SH
Department of Neurosurgery, Kyungpook National University Hospital 50, Samduk-2-ga, Jung-gu, Daegu, 700-721, South Korea. nsdoctor@naver.com
Hwang
Sung-Kyoo
SK
Kang
Dong-Hun
DH
Park
Jaechan
J
Hwang
Jeong-Hyun
JH
Sung
Joo-Kyung
JK
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control; D016634:Radiosurgery / Q000379:methods*; D012189:Retrospective Studies; D013238:Stereotaxic Techniques; D012668:Trigeminal Ganglion / Q000033:anatomy & histology / Q000601:surgery; D014276:Trigeminal Nerve / Q000033:anatomy & histology* / Q000601:surgery*; D014277:Trigeminal Neuralgia / Q000503:physiopathology / Q000601:surgery*