Evaluation of CyberKnife Radiosurgery for Recurrent Trigeminal Neuralgia

Abstract

Stereotactic radiosurgery (SRS) has evolved as an accepted treatment for medication resistant trigeminal neuralgia. Initial results are very good but follow-up over three to five years shows a gradual return of pain in up to 50% of treated patients, often requiring further treatment. The results with repeat SRS using the isocentric Gamma Knife (GK) (Elekta, Stockholm, Sweden), especially in patients having initially good results, are very similar to the outcomes after the initial treatment although there is an increased risk of residual facial numbness secondary to the additional radiation dose to the trigeminal nerve. However, after 2000, non-isocentric SRS systems began to be used for treating trigeminal neuralgia including the CyberKnife (CK) (Accuray, Sunnyvale, California) as well as various linear accelerator (LINAC) based systems. This report specifically examines a series of recurrent trigeminal cases treated by the same group of physicians with the CK system. Similar doses and locations on the trigeminal nerve and/or the root entry zone were used for both initial and repeat SRS treatment regardless of system used. Although there are numerous series reporting the use of GK for recurrent treatment for recurrent trigeminal neuralgia, there are no series reviewing the results and long-term effectiveness using CK for repeat SRS for recurrent trigeminal pain. We reviewed 23 cases that had initial treatment for trigeminal neuralgia either surgically or with SRS with either the GK or CK and then a later second procedure only with CK. The follow-up after the second CK SRS ranged from three to 13 years found that the results are very similar to the multiple reports in the literature describing second or third SRS treatments with the GK. Results of repeat radiosurgery treatment of recurrent trigeminal neuralgia appear to be independent of the system used and are primarily based on proper target and dose to the trigeminal nerve.

Radiocirugía CyberKnife para la neuralgia bilateral del trigémino refractaria. Caso clínico

“…This is an aspect to take into account in this entity, since a previous history of invasive surgical interventions may diminish the therapeutic efficacy of CyberKnife 11 . The expected risk or complication of this treatment is facial numbness in 4.3-12.0% of cases, which can best be described as a side effect positively associated with effective pain relief and directly proportional to the amount of Gy applied 11 , 13 . So far, no mortality has been attributed to CyberKnife in any study, and among other complications found are cerebral edema, radionecrosis, hemiparesis, and dysesthesia 15 .…”

“…Se desestimaron otras opciones como neurolisis del ganglio de gaser y rizotomía, por la posibilidad de un manejo menos invasivo como la radiocirugía, que en casos persistentes de neuralgia del trigémino, forman parte de las opciones dentro de las nuevas guías 3 , 11 , 13 , 14 , 16 por poseer mayor efectividad en eliminación del dolor 3 , 6 y menor probabilidad de complicaciones como: hipoacusia, hipoestesia facial, fístula del líquido cefalorraquídeo o hemorragia postquirúrgica 2 . Por tal motivo con idea de integrar nuevas alternativas y lograr obtener resultados diferentes, se determinó la realización de radiocirugía por CyberKnife, teniendo en cuenta otros reportes de casos y estudios que constatan sus beneficios 3 , 11 - 16 , 19 , además de los antecedentes de diversos procedimientos fallidos realizados a la paciente como acupuntura, medicación exagerada, descompresión microvascular y su sintomatología dolorosa que afectaba la parte social y mental.…”

Viability of the virtual cone technique using a fixed small multi‐leaf collimator field for stereotactic radiosurgery of trigeminal neuralgia

“…Currently, the cone-based SRS using the specialized machines such as GammaKnife, CyberKnife, and other LINACs remains the standard practice for the treatment of small intracranial lesions such as trigeminal neuralgia (TGN). [10][11][12][13] However, it poses several challenges; need of (1) a cone-specific dose calculation, (2) ensuring geometric precision for each cone collimating system, (3) rigorous patient-specific quality assurance (QA), and (4) avoidance of collision for cone-based arcs. It should be noted that a well-defined spherical or ellipsoidal dose distribution along with a high mechanical precision in dose delivery is required for such treatment.…”

Repeat CyberKnife Radiosurgery for Trigeminal Neuralgia: Outcomes and Complications

“…A limited number of systematic reviews and retrospective series report relevant findings. 9–11 As with initial RS for TN, only a limited number of studies report CKRS in the setting of re-treatment. 7,11…”

“…9–11 As with initial RS for TN, only a limited number of studies report CKRS in the setting of re-treatment. 7,11…”