Stereotactic Radiosurgery for Glossopharyngeal Neuralgia: An International Multicenter Study

Transcription

1 Stereotactic Radiosurgery for Glossopharyngeal Neuralgia: An International Multicenter Study University of Pittsburgh Hideyuki Kano, MD, PhD L. Dade Lunsford, MD Hospital Na Homolce, Prague Dusan Urgosik, MD Roman Liscak, MD Mayo Clinic Bruce E. Pollock, MD University of Virginia Cohen Inbar, MD Jason Sheehan, MD, PhD Cleveland Clinic Mayur Sharma, MD Danilo Silva, MD Gene, Barnett, MD University of Sherbrooke David Mathieu, MD Conflict of Interest: Dr. Lunsford is a consultant and stockholder for A B Elekta. 1

2 Introduction Glossopharyngeal neuralgia (GN) is a rare pain syndrome that affects the ninth cranial nerve resulting in sharp, stabbing pain in the back of the throat, tongue, and inner ear. GN can be caused by vascular compression, however preop imaging does not always demonstrate a vascular cause. Initial treatment is medical using agents such as carbamazepine and gabapentin. Surgical management options include microvascular decompression and nerve section Gamma Knife radiosurgery is a minimally invasive additional surgical option for intractable GN. 2

3 Objective Selected centers of The International Gamma Knife Research Foundation (IGKRF) retrospectively evaluated outcomes of GK SRS for this relatively rare clinical indication This report is based on deidentified patient data provided by six academic medical centers who participated in this outcome assessment. 3

4 GK SRS Planning Target: root entry zone, cisternal segment Max dose: 80 Gy, Single 4 mm collimeter 4

5 Patient characteristics (N=22) characteristics male 8 female 14 Median age (range) 65 (34-83) Prior failed surgical management MVD (14M and 50M before SRS) 2 Balloon compression (3M before SRS) 1 Nerve block (17M before SRS) 1 GK for trigeminal nerve (NA) 1 Neurovascular compression on MRI 15 5

6 Pain and GK SRS Characteristics (N=22) Characteristics Median or N Interval from Initial Pain to GK (months) 46 (1-240) Lasting time of pain for each event 0-30 sec sec 6 > 1 min 7 Pain location throat 18 tongue 8 ear 14 Median Max dose (Gy) 80 (80-90) Collimeter size (mm) 4 Number of Isocenters 1 (1 pt: 2) 6 Median Clinical Follow-up after SRS = 45 M (6-120M)

7 Barrow Neurological Institute Scale Pain Grade I CPR Definition No pain and taking no med. II IIIa IIIb IV V APR Occasional pain, but taking no med. No pain, but taking med. Pain improved, but adequately controlled with med. Some pain, not adequately controlled with med. No relief CPR: complete pain relief APR: adequate pain relief 7

8 Probability of Initial Complete Pain Relief (BNI I) 11/22 30-day IPR=41% 60-day IPR=52% 90-day IPR=52% IPR=Initial pain relief rate 8

9 Probability of Initial Pain Relief (BNI I-IIIb) 16/22 30-day IPR=50% 60-day IPR=64% 90-day IPR=73% IPR=Initial pain relief rate 9

10 Probability of Maintaining Pain Relief (BNI I) after initial SRS BNI I: N=7/11 1-year MPR=59% 2-year MPR=44% 3-year MPR=33% 5-year MPR=33% 7-year MPR=22% MPR=Maintenance of pain relief rate 10

11 Probability of Maintaining Pain Relief (BNI I-IIIb) after initial SRS BNI I-IIIb: N=8/16 1-year MPR=63% 2-year MPR=49% 3-year MPR=38% 5-year MPR=38% 7-year MPR=28% MPR=Maintenance of pain relief rate 11

12 Adverse Radiation Effects 2 patients developed persistent hypesthesia in the palatoglossal arch (5M and 8M after SRS) No patient developed changes in vocal cord function or swallowing disorders No patient developed aspiration 12

13 Additional Management after SRS N Results Repeat SRS for CN IX 6 BNI I: 4, rec (50M): 1, no FU: 1 MVD 2 BNI I:1, V:1 MVD + Nerve section 2 BNI IIIa: 2 Nerve block 1 Initial Pain Relief but rec Repeat SRS for CN V 2 BNI I:2 These 2 pts had initial pain relief and no rec but required SRS for trigeminal neuralgia. 13

14 Probability of Maintaining Complete Pain Relief (BNI I) after initial and Repeat SRS BNI I: N=11 1-year MPR=55% 2-year MPR=55% 3-year MPR=55% 5-year MPR=55% 7-year MPR=41% MPR=Maintenance of pain relief rate 14

15 Probability of Maintaining Pain Relief (BNI I-IIIb) after initial and Repeat SRS BNI I-IIIb: N=12 1-year MPR=68% 2-year MPR=68% 3-year MPR=63% 5-year MPR=63% 7-year MPR=42% MPR=Maintenance of pain relief rate 15

16 Summary Complete Pain Relief (BNI I) Initial complete pain relief: 11/22 (50%) Maintaining BNI I: 7/11 Adequate Pain Relief (BNI I-IIIb) Initial pain relief (BNI I-IIIb): 16/22 (73%) Maintaining BNI I-IIIb: 8/16 Repeat SRS 4 of 6 patients who had repeat SRS maintained BNI I Final Results after 1-2 SRS Maintaining BNI I pain relief: 11/22 Maintaining BNI I-IIIb pain relief 12/22 16

17 Conclusions In this limited experience GK SRS for medically intractable glossopharyngeal neuralgia provided eventual pain control or improvement in the majority of patients (73%). It was associated with a low minor side effect risk (9%). Lasting pain reduction occurred in 55% of patients, some of whom required two SRS procedures. Further experience is warranted in this surgical option for patients who are poor candidates for initial microvascular decompression. A prospective trial using a higher initial dose may be warranted. 17