Hayden Danyluk1,2, Jennifer Andrews2, Rohit Kesarwani2, Peter Seres3, Robert Broad2, B Matt Wheatley2, Tejas Sankar4. 1. Division of Surgical Research, Department of Surgery, University of Alberta, 3-002 Li Ka Shing Centre For Research, 11203 - 87 Ave NW, Edmonton, AB, T6G 2H5, Canada. 2. Division of Neurosurgery, Department of Surgery, University of Alberta, 2D Department of Surgery, University of Alberta Hospital, 8440-112 Street NW, Edmonton, AB, T6G 2B7, Canada. 3. Department of Biomedical Engineering, Faculty of Medicine and Dentistry, University of Alberta, 1098 Research Transition Facility, Edmonton, AB, T6G 2V2, Canada. 4. Division of Neurosurgery, Department of Surgery, University of Alberta, 2D Department of Surgery, University of Alberta Hospital, 8440-112 Street NW, Edmonton, AB, T6G 2B7, Canada. tejas.sankar@gmail.com.
Abstract
BACKGROUND: Medically-refractory trigeminal neuralgia (TN) can be treated successfully with operative intervention, but a significant proportion of patients are non-responders despite undergoing technically successful surgery. The thalamus is a key component of the trigeminal sensory pathway involved in transmitting facial pain, but the role of the thalamus in TN, and its influence on durability of pain relief after TN surgery, are relatively understudied. We aimed to test the hypothesis that variations in thalamic structure and metabolism are related to surgical non-response in TN. METHODS: We performed a longitudinal, peri-operative neuroimaging study of the thalamus in medically-refractory TN patients undergoing microvascular decompression or percutaneous balloon compression rhizotomy. Patients underwent structural MRI and MR spectroscopy scans pre-operatively and at 1-week following surgery, and were classified as responders or non-responders based on 1-year post-operative pain outcome. Thalamus volume, shape, and metabolite concentration (choline/creatine [Cho/Cr] and N-acetylaspartate/creatine [NAA/Cr]) were evaluated at baseline and 1-week, and compared between responders, non-responders, and healthy controls. RESULTS: Twenty healthy controls and 23 patients with medically-refractory TN treated surgically (17 responders, 6 non-responders) were included. Pre-operatively, TN patients as a group showed significantly larger thalamus volume contralateral to the side of facial pain. However, vertex-wise shape analysis showed significant contralateral thalamus volume reduction in non-responders compared to responders in an axially-oriented band spanning the outer thalamic circumference (peak p = 0.019). Further, while pre-operative thalamic metabolite concentrations did not differ between responders and non-responders, as early as 1-week after surgery, long-term non-responders showed a distinct decrease in contralateral thalamic Cho/Cr and NAA/Cr, irrespective of surgery type, which was not observed in responders. CONCLUSIONS: Atrophy of the contralateral thalamus is a consistent feature across patients with medically-refractory TN. Regional alterations in preoperative thalamic structure, and very early post-operative metabolic changes in the thalamus, both appear to influence the durability of pain relief after TN surgery.
BACKGROUND: Medically-refractory trigeminal neuralgia (TN) can be treated successfully with operative intervention, but a significant proportion of patients are non-responders despite undergoing technically successful surgery. The thalamus is a key component of the trigeminal sensory pathway involved in transmitting facial pain, but the role of the thalamus in TN, and its influence on durability of pain relief after TN surgery, are relatively understudied. We aimed to test the hypothesis that variations in thalamic structure and metabolism are related to surgical non-response in TN. METHODS: We performed a longitudinal, peri-operative neuroimaging study of the thalamus in medically-refractory TNpatients undergoing microvascular decompression or percutaneous balloon compression rhizotomy. Patients underwent structural MRI and MR spectroscopy scans pre-operatively and at 1-week following surgery, and were classified as responders or non-responders based on 1-year post-operative pain outcome. Thalamus volume, shape, and metabolite concentration (choline/creatine [Cho/Cr] and N-acetylaspartate/creatine [NAA/Cr]) were evaluated at baseline and 1-week, and compared between responders, non-responders, and healthy controls. RESULTS: Twenty healthy controls and 23 patients with medically-refractory TN treated surgically (17 responders, 6 non-responders) were included. Pre-operatively, TNpatients as a group showed significantly larger thalamus volume contralateral to the side of facial pain. However, vertex-wise shape analysis showed significant contralateral thalamus volume reduction in non-responders compared to responders in an axially-oriented band spanning the outer thalamic circumference (peak p = 0.019). Further, while pre-operative thalamic metabolite concentrations did not differ between responders and non-responders, as early as 1-week after surgery, long-term non-responders showed a distinct decrease in contralateral thalamic Cho/Cr and NAA/Cr, irrespective of surgery type, which was not observed in responders. CONCLUSIONS:Atrophy of the contralateral thalamus is a consistent feature across patients with medically-refractory TN. Regional alterations in preoperative thalamic structure, and very early post-operative metabolic changes in the thalamus, both appear to influence the durability of pain relief after TN surgery.
Authors: Paulo Roberto Lacerda Leal; Jean Amédée Roch; Marc Hermier; Miguel Angelo Nobre Souza; Gerardo Cristino-Filho; Marc Sindou Journal: Pain Date: 2011-08-10 Impact factor: 6.961
Authors: Paulo Roberto Lacerda Leal; Charlotte Barbier; Marc Hermier; Miguel Angelo Souza; Gerardo Cristino-Filho; Marc Sindou Journal: J Neurosurg Date: 2014-04-18 Impact factor: 5.115