Movement disorders J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp-2018-318240 on 18 October 2018. Downloaded from REVIEW Outcomes from stereotactic surgery for essential tremor Robert Francis Dallapiazza,1 Darrin J Lee,1 Philippe De Vloo,1 Anton Fomenko,1 Clement Hamani,1 Mojgan Hodaie,1 Suneil K Kalia,1 Alfonso Fasano,2,3,4 Andres M Lozano1 ► Additional material is ABSTRact can profoundly impact the quality of life in patients published online only. To view There are several different surgical procedures that with severe symptoms.5 6 Patients report difficulty please visit the journal online with everyday tasks such as eating, drinking, hand- (http:// dx. doi. org/ 10. 1136/ are used to treat essential tremor (ET), including deep jnnp- 2018- 318240). brain stimulation (DBS) and thalamotomy procedures writing and dressing. Many patients also experi- with radiofrequency (RF), radiosurgery (RS) and most ence social embarrassment regarding their tremor. 1Division of Neurosurgery, recently, focused ultrasound (FUS). Choosing a surgical Some will refrain from dining in public, and others University of Toronto, Toronto, treatment requires a careful presentation and discussion will retire from employment early due to disabling Ontario, Canada 2Edmond J. Safra Program in of the benefits and drawbacks of each.W e conducted a symptoms. Parkinson’s Disease, Morton literature review to compare the attributes and make an Medical therapy is the first-line treatment for and Gloria Shulman Movement appraisal of these various procedures. DBS was the most ET (particularly beta-blockers and primidone).7 Disorders Clinic, Toronto commonly reported treatment for ET. One-year tremor However, medications alone are often insufficient Western Hospital, Toronto, reductions ranged from 53% to 63% with unilateral to control severe symptoms and can have undesir- Ontario, Canada 8 3Division of Neurology, Vim DBS. Similar improvements were demonstrated able side effects. Currently, there are four effec- University of Toronto, Toronto, with RF (range, 74%–90%), RS (range, 48%–63%) tive surgical treatments for patients with ET. Most Ontario, Canada surgical interventions target the ventral interme- 4 and FUS thalamotomy (range, 35%–75%). Overall, Krembil Research Institute, bilateral Vim DBS demonstrated more improvement diate nucleus (Vim) of the thalamus and the adjacent Toronto, Ontario, Canada in tremor reduction since both upper extremities were ventral white matter tracts.8 The purpose of this review is to present the existing literature regarding copyright. Correspondence to treated (range, 66%–78%). Several studies show Dr Robert Francis Dallapiazza, continued beneficial effects from DBS up to five years. outcomes of the four commonly performed surgical Division of Neurosurgery, Long-term follow-up data also support RF and gamma treatments for ET: (1) deep brain stimulation (DBS), Toronto Western Hospital, knife radiosurgical thalamotomy treatments. Quality of (2) radiofrequency (RF) thalamotomy, (3) gamma Toronto, ON M5T 2S8, Canada; life measures were similarly improved among patients knife radiosurgical (GKRS) thalamotomy and (4) rfdallapiazza@ gmail. com who received all treatments. Paraesthesias, dysarthria focused ultrasound (FUS) thalamotomy (table 1) Received 16 February 2018 and ataxia were commonly reported adverse effects and to provide a procedural comparison (table 2). Revised 17 July 2018 in all treatment modalities and were more common This information provides a useful platform for Accepted 25 September 2018 with bilateral DBS surgery. Many of the neurological clinicians and patients to review and discuss the complications were transient and resolved after surgery. nuances of the various surgical treatments for ET. DBS surgery had the added benefit of programming adjustments to minimise stimulation-related http://jnnp.bmj.com/ METHODS complications. Permanent neurological complications In this review, we follow the Preferred Reporting were most commonly reported for RF thalamotomy. Items for Systematic Reviews and Meta-Analysis Thalamic DBS is an effective, safe treatment with a long (PRISMA) standards. We searched Pubmed (1946– history. For patients who are medically unfit or reluctant October 2017) by using both controlled vocab- to undergo DBS, several thalamic lesioning methods have ulary words and synonymous free text words for parallel benefits to unilateral DBS surgery.E ach of these both the indication (ET) and treatment modalities surgical modalities has its own nuance for treatment on September 26, 2021 by guest. Protected (RF ablation, DBS, stereotactic radiosurgery (RS), and patient selection. These factors should be carefully FUS). The search was not limited by study design considered by both neurosurgeons and patients when or language. Studies with unblinded and blinded selecting an appropriate treatment for ET. assessments of outcome were included. Studies that © Author(s) (or their reported results from five or more patients using a employer(s)) 2018. Re-use standard ET severity scale were included. permitted under CC BY-NC. No INTRODUCTION The primary objective was the assessment of effi- commercial re-use. See rights Essential tremor (ET) is a debated, heterogeneous cacy and safety of the different modalities in the and permissions. Published by BMJ. entity that is historically considered the most treatment of ET. The secondary objective was the common movement disorder in adults with an esti- assessment of the treatment outcome on the activ- To cite: Dallapiazza RF, Lee mated prevalence of 0.5%–5%.1 2 ET typically pres- ities of daily living (ADLs) and the quality of life. DJ, De Vloo P, et al. J Neurol ents with kinetic, intention and/or postural tremor The primary efficacy outcome was the difference Neurosurg Psychiatry Epub ahead of print: [please that symmetrically affects the upper extremities, in tremor before and after treatment. We examined include Day Month Year]. although variable involvement of the neck, face, studies that report tremor improvement according doi:10.1136/jnnp-2018- vocal cords and lower extremities can be seen.3 4 to the Fahn-Tolosa-Marin rating scale, the tremor 318240 ET is not a life-threatening condition; however, it subsection of the Unified Parkinson’s Disease Dallapiazza RF, et al. J Neurol Neurosurg Psychiatry 2018;0:1–9. doi:10.1136/jnnp-2018-318240 1 Movement disorders J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp-2018-318240 on 18 October 2018. Downloaded from patients’ tremor can be electrically recorded, and disruption of Table 1 A comparison of surgical outcomes for ET this activity has long been known to arrest tremor. DBS FUS GKRS RF Vim thalamic DBS surgery is typically performed under local Experience 1093 patients 151 patients 360 patients 278 patients anaesthesia but can also be performed under general anaes- since 1998 since 2013 since 2007 since 1986 thesia. A frontal burr hole is drilled, and thalamic intracranial Level of Evidence, Level 2 Level 1 Level 4 Levels 2–4 electrodes are implanted. Microelectrode recordings for target (OCEM) mapping can be used to refine the final electrode placement. Tremor control, Unilateral: Unilateral: Unilateral: Unilateral: Macroelectrode stimulation can further facilitate optimisation 12-month follow- 53.4%–62.8% 35%–75% 48%–63% 74%–90% of the target and clinical benefit and establish the presence of up Bilateral Bilateral: no Bilateral: no Bilateral: no stimulation-induced side effects. Once in place, electrodes are 66%–78% data data data secured to the skull and extension wires are used to connect the Tremor control, Unilateral: Unilateral: Unilateral: Unilateral: long-term follow- 60%–75% 56% 3%–63% 74%–90% intracranial electrodes to an implanted pulse generator under up Bilateral general anaesthesia. The tremor suppressive effects of acute DBS 75% are immediately evident. Quality of life 57.9%–82% 37%–73% 65% 47% We included 53 case series of DBS for ET (40 case series of Vim improvements DBS, 13 cases of posterior subthalamic area/caudal zona incerta Complications (PSA/cZI) DBS). These reports include 1093 patients (913 Vim, (range, transient Unilateral, 180 PSA/cZI). A majority of operations were performed unilat- and permanent) bilateral erally (637 Vim, 121 PSA/cZI) compared with bilaterally (276 11%–39%, Vim, 59 PSA/cZI). Bilateral procedures were mostly performed Dysarthria 22%–75% 3% 1%–3% 4.6%–29% during a single procedure. 9%–17%, Several studies have shown that unilateral Vim DBS reduces Ataxia/gait 56%–86% 23% 0%–17% 5%–27% overall tremor at 12 months. With unilateral Vim DBS, the Paraesthesia 5%, 5.9% 14%–25% 1%–9% 6%–42% overall tremor reduction that was reported ranged from 53.4% to Hemiparesis 4.5%, 6.7% 2%–7% 0%–8% 0%–34% 62.8% (online supplementary table 1). Action tremor involving ET, essential tremor; DBS, deep brain stimulation; FUS, focused ultrasound; GKRS, the contralateral upper extremities was markedly improved with gamma knife radiosurgical thalamotomy; RF, radiofrequency. unilateral DBS with a reduction of tremor scores ranging from 38.2% to 78.9%.9 10 At longer follow-up out to 5 years, data Rating Scale and/or the Unified Tremor Rating Scale. The demonstrated excellent contralateral upper extremity action primary safety outcome was the frequency, types and severity of tremor reduction (60.3%–75%) among patients with unilateral copyright. the adverse events following the different treatment modalities. Vim DBS.11 12 Blomstedt et al reported a 60.3% reduction