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Anil A. Dhople, Jared R. Adams, William W. Maggio, Shahid A. Naqvi, William F. Regine, and Young Kwok

Object

Few long-term studies of Gamma Knife surgery (GKS) for trigeminal neuralgia (TN) exist. The authors report their long-term experience with the use of GKS in a previously reported cohort of patients with TN that has now been followed since 1996.

Methods

One hundred twelve patients with TN were treated with GKS at the University of Maryland between June 1996 and July 2001. Of these, 67% had no invasive operations for TN prior to GKS, 13% had 1, 4% had 2, and 16% had ≥ 3. The right side was affected in 56% of cases, predominantly involving V2 (26%), V3 (24%), or a combination of both (18%) branches. The median age at diagnosis was 56 years, and median age at GKS was 64 years. The median prescription dose of 75 Gy (range 70–80 Gy) was delivered to the involved trigeminal nerve root entry zone. The authors assessed the degree of pain before and after GKS by using the Barrow Neurological Institute (BNI) pain scale.

Results

In total, 102 patients took the survey at least once, for a response rate of 91%. Although not found to alter the conclusions of this study, 7 cases of atypical TN were found and these patients were removed, for a total of 95 cases herein analyzed. The median follow-up was 5.6 years (range 13–115 months). Before GKS, 88% of patients categorized their pain as BNI IV or V (inadequate control or severe pain on medication), whereas the remainder described their pain as BNI III (some pain, but controlled on medication). After GKS, 64% reported a BNI score of I (no pain, no medications), 5% had BNI II (no pain, still on medication), 12% had BNI III, and 19% reported a BNI score of IV or V. The median time to response was 2 weeks (range 0–12 weeks) and the median response duration was 32 months (range 0–112 months). Eighty-one percent reported initial pain relief, and actuarial rates of freedom from treatment failure at 1, 3, 5, and 7 years were 60, 41, 34, and 22%, respectively. Response duration was significantly better for those who had no prior invasive treatment versus those in whom a previous surgical intervention had failed (32 vs 21 months, p < 0.02). New bothersome facial numbness was reported in 6% of cases.

Conclusions

This study represents one of the longest reported median follow-up periods and actuarial results for a cohort of patients with classic TN treated with GKS. Although GKS achieves excellent rates of initial pain relief, these results suggest a steady rate of late failure, particularly among patients who had undergone prior invasive surgical treatment. Despite a higher than expected recurrence rate, GKS remains a viable treatment option, particularly for patients who have had no prior invasive procedures. Patients with recurrences can still be offered salvage therapy with either repeat GKS, microvascular decompression, or rhizotomy.

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William L. Young, Pui-Yan Kwok, Ludmila Pawlikowska, Michael T. Lawton, Helen Kim, Pirro G. Hysi, and Douglas A. Marchuk

Object.

Important central nervous system (CNS) manifestations in patients with hereditary hemorrhagic telangiectasia (HHT) include arteriovenous malformations (AVMs) and dural arteriovenous fistulas (DAVFs). Hereditary hemorrhagic telangiectasia is caused by germline mutations of two genes: ENG (HHT Type 1) and ACVRL1 (HHT Type 2). The ENG gene variations have been associated with the formation of intracranial aneurysms. The authors studied whether sequence variations in ACVRL1 or ENG are associated with the development of clinically sporadic arteriovenous dysplasias and aneurysms of the CNS.

Methods.

The coding sequence (in 44 patients with AVMs and 27 with aneurysms) and the 5′ end and the polyA site (in 53 patients with AVMs) of the ACVRL1 gene were analyzed for sequence variations using direct sequencing and single-strand conformational polymorphism analysis. One ENG and three ACVRL1 gene polymorphisms were genotyped using restriction enzyme–based analysis in 101 patients with sporadic AVMs and DAVFs of the CNS, 79 patients treated for intracranial aneurysms, and 202 control volunteers.

The authors identified a statistically significant association between the IVS3 −35A/T polymorphism in intron 3 of the ACVRL1 gene and the development of AVMs and DAVFs (p = 0.004; odds ratio [OR] 1.73; 95% confidence interval [CI] 1.19–2.51; after adjustments for age and sex), but not aneurysms (crude OR 0.82; 95% CI 0.55–1.18).

Conclusions.

The results of this study link ACVRL1 (HHT Type 2 gene) to the formation of the clinically sporadic variants of vascular malformations of the CNS most commonly seen in patients with HHT, that is, AVMs and DAVFs.

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Michael T. Koltz, Adam J. Polifka, Andreas Saltos, Robert G. Slawson, Young Kwok, E. Francois Aldrich, and J. Marc Simard

Object

The object of this study was to assess outcomes in patients with arteriovenous malformations (AVMs) treated by Gamma Knife stereotactic radiosurgery (SRS); lesions were stratified by size, symptomatology, and Spetzler-Martin (S-M) grade.

Methods

The authors performed a retrospective analysis of 102 patients treated for an AVM with single-dose or staged-dose SRS between 1993 and 2004. Lesions were grouped by S-M grade, as hemorrhagic or nonhemorrhagic, and as small (< 3 cm) or large (≥ 3 cm). Outcomes included death, morbidity (new neurological deficit, new-onset seizure, or hemorrhage/rehemorrhage), nidus obliteration, and Karnofsky Performance Scale score.

Results

The mean follow-up was 8.5 years (range 5–16 years). Overall nidus obliteration (achieved in 75% of patients) and morbidity (19%) correlated with lesion size and S-M grade. For S-M Grade I–III AVMs, nonhemorrhagic and hemorrhagic combined, treatment yielded obliteration rates of 100%, 89%, and 86%, respectively; high functional status (Karnofsky Performance Scale Score ≥ 80); and 1% mortality. For S-M Grade IV and V AVMs, outcomes were less favorable, with obliteration rates of 54% and 0%, respectively. The AVMs that were not obliterated had a mean reduction in nidus volume of 69% (range 35%–96%). On long-term follow-up, 10% of patients experienced hemorrhage/rehemorrhage (6% mortality rate), which correlated with lesion size and S-M grade; the mean interval to hemorrhage was 81 months.

Conclusions

For patients with S-M Grade I–III AVMs, SRS offers outcomes that are favorable and that, except for the timing of obliteration, appear to be comparable to surgical outcomes reported for the same S-M grades. Staged-dose SRS results in lesion obliteration in half of patients with S-M Grade IV lesions.

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Feng Xu, Bing Leng, and Donglei Song