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Robotic Image-Guided Radiosurgery for Trigeminal Neuralgia: Results after 10 Years



Abstract

Objective: 668 patients with Trigeminal Neuralgia (TN) have been treated at the Cyberknife Center of CDI (Milan) during the last 12 years. Long-term follow-up (10 years) is available for 84 patients.

Methods: Patients with typical TN and severe medically-refractory pain were selected and treated with image-guided robotic radiosurgery (CyberKnife) by a single neurosurgeon (PR). Treatment was delivered in single session without hospitalization, lasting on average 55 minutes. Pre-operative imaging included thin cuts (0,5 mm) post-contrast stereotactic head CT as well as volumetric post-contrast MR (MPRAGE) integrated by Fiesta images. A 6 mm segment along the midcisternal course of the nerve was drawn. A 60 Gy dose was prescribed to the 80% isodose. The same dose was delivered if a second treatment was needed; over time the second dose was reduced to 45 G. Clinical re-evaluation was performed regularly for 4 years, then yearly follow-up calls were made or further clinical evaluations performed if needed. Visual analogue scores (VAS, 0-10) and Barrow Neurological Institute (BNI) scale (I-V) have been used to assess the pain level before the treatment and during the follow-up. VAS scores >7 and BNI grade IV-V, both indicating severe pain, were required to undergo the treatment. A reduction of VAS score >5 and inclusion in the BNI class I-II were considered as a meaningful way to assess development and duration of pain relief as well as pain relapses. BNI facial numbness scale (I-IV) was used to assess the development of sensory disturbances following the treatment. Patient with sensory complications fell in the III and IV BNI numbness scores.

Results: Pain relief rate in 343 patients was 92% after 6 month, 87% after 1 year and 76% after 3 years. 5- and 10-years follow-up is available for 84 patients, with relief rates of 74% and 72% respectively. 15 patients within this group required a second treatment due to lack of efficacy of the first treatment (4) or pain relapse (11). BNI grade III sensory complications were found in 7 and 5 patients after, respectively, 5 and 10 years. Except 2 patients receiving a single treatment, in which the symptoms regressed from bothering (grade III) to non- bothering (grade II) between the 5 and 10 years time point, all the others received two treatments (both delivering 60 Gy). One further patient developed dysesthesias (BNI grade IV) after 2 treatments delivering 60 Gy (the second one done because of relapsing pain) and received a contralateral medial thalamotomy 7 years after the first treatment, with regression to grade II BNI score. Overall the rate of sensory complications at 5 and 10 years was, respectively, 9,5% (8 Patients) and 5,9%(5 patients).

Pain relief rate 10 years after robotic image-guided radiosurgery for TN was satisfactory in over 2/3 of the patients treated. Sensory complications in the patients receiving 2 treatments delivering 60 Gy to the same 6 mm target led to the reduction of second treatment dose to 45 Gy. This lower dose was later observed to induce a much lower rate of sensory complications without affecting pain relief rates. Of note, aside from sensory complications, no other neurological complications have been found.

Conclusion: Long-term follow-up confirms the efficacy and safety of image-guided robotic radiosurgery for TN. Second treatments are useful to achieve pain relief in patients not responding to or relapsing after a first treatment.

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abstract
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Robotic Image-Guided Radiosurgery for Trigeminal Neuralgia: Results after 10 Years


Author Information

Pantaleo Romanelli Corresponding Author

Neurosurgery, Cyberknife Center, Centro Diagnostico Italiano, Milano, ITA

Livia Corinna Bianchi

Radiation Oncology, Cyberknife Center, Centro Diagnostico Italiano, Milano, ITA

Giancarlo Beltramo

Radiation Oncology, Cyberknife Center, Centro Diagnostico Italiano, Milano, ITA


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