Selective peripheral denervation for cervical dystonia: long-term follow-up

Comparison of different surgical strategies for cervical dystonia: Evidence from Bayesian network analysis

BACKGROUND AND PURPOSE

Several surgical techniques have been used to treat cervical dystonia (CD), however, to date, the optimal surgical technique for CD remains controversial. We therefore conducted the first network meta-analysis to compare different surgical strategies for CD to inform clinical practice.

METHODS

Electronic databases were searched for surgical strategies for treating CD. The primary outcome was improvement in total Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) score. Subgroup analysis was performed to compare short-term (< 1 year) and long-term (≥ 1 year) outcomes. Safety outcomes included surgery-related adverse events (AEs).

RESULTS

A total of 55 trials with 2032 patients employing five surgical strategies were identified, including globus pallidus internus (GPi)/subthalamic nucleus (STN)-deep brain stimulation (DBS), selective peripheral denervation (SPD), microvascular decompression (MVD) and pallidotomy. All strategies led to significant improvement in total TWSTRS score (mean improvement range 18.65-28.22). GPi-DBS showed significantly greater enhancement than SPD for the whole dataset (mean difference [MD] 7.03, 95% credible interval [Crl] 1.53-12.56), while both GPi-DBS (MD 8.05, 95% Crl 2.35-13.80) and STN-DBS (MD 10.71, 95% Crl 2.22-19.20) exhibited more long-term improvement than SPD. Regarding safety outcomes, GPi/STN-DBS and MVD were associated with fewer surgery-related AEs than SPD (ln odds ratio range -1.68 to -1.41).

CONCLUSION

We conclude that DBS should be the preferred surgical option for CD, and the STN is a promising alternative target choice due to its comparable efficacy with the GPi. However, more direct evidence is still required.

Evaluation of outcome of different neurosurgical modalities in management of cervical dystonia

Background

Cervical dystonia is the most common form of focal dystonia and is managed by multiple modalities including repeated botulinum toxin injections, in addition to medical treatment with anticholinergics, muscle relaxants, and physiotherapy. However, surgical interventions could be beneficial in otherwise refractory patients. This study aims to report our experience in the neurosurgical management of cervical dystonia and evaluate patient outcomes using reliable outcome scores for the assessment of patients with cervical dystonia and possible complications. This case series study was conducted on 19 patients with cervical dystonia of different etiologies who underwent surgical management [ten patients underwent selective peripheral denervation, five patients underwent pallidotomy, and four patients underwent bilateral globus pallidus internus (GPi) deep brain stimulation (DBS)] in the period between July 2018 and June 2021 at Ain Shams University Hospitals, Cairo, Egypt. With the assessment of surgical outcomes using the Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) and the Tsui scale 6 months postoperatively.

Results

Surgical management of patients with cervical dystonia of either primary or secondary etiology was associated with significant improvement in head and neck postures after 6 months without major complications associated with the different surgical procedures. The mean improvement in total TWSTRS and Tsui scores were 51.2% and 64.8%, respectively, compared with preoperative scores, while the mean improvement in the TWSTRS subscales (severity, disability, and pain) were 40.2%, 66.9%, and 58.3%, respectively.

Conclusion

Cervical dystonia patients in whom non-surgical options have failed to alleviate their symptoms can be managed surgically leading to significant improvements with minimal adverse effects. However, surgical treatment should be tailored according to several factors including but not limited to the etiology, pattern of dystonic activity, and comorbidities. Therefore, management should be tailored to achieve long-term improvement with minimal risk of complications.

Bilateral subthalamic nucleus deep brain stimulation for refractory isolated cervical dystonia

Subthalamic nucleus (STN) deep brain stimulation (DBS) has been proven to be an alternative target choice for refractory isolated cervical dystonia (CD). However, assessments of its short and long-term safety, efficacy, and sustained effectiveness have been limited to few reports. Here, we evaluated nine consecutive refractory isolated CD patients who underwent bilateral STN DBS and accepted to short and long-term follow-up in this retrospective study. Seven time points were used to see the Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) scores (pre-operation [baseline], 1, 3, 6, 12, 24 months post-operation and last follow-up) to assess improvement of dystonic symptoms. The 36-item Short-Form General Health Survey (SF-36) scores obtained at pre-operation and last follow-up to assess the changes in quality of life. All patients tolerated surgery well and acquired observable clinical benefits from STN DBS therapy. All patients achieved a considerable improvement in quality of life at the last follow-up. The hardware-related adverse events can be tolerated and the stimulation-related adverse events can be ameliorated by programming. Our data support the idea that bilateral STN DBS is a safety and effective method for the treatment of refractory isolated CD, with persistent and remarkable improvement in both movement and quality of life.

Modified McKenzie-Dandy operation for a cervical dystonia patient who failed selective peripheral denervation: A case report and literature review

BACKGROUND

Cervical dystonia (CD) is a rare and difficult-to-treat disorder. Various neurosurgical options are available, each with its own set of advantages and disadvantages. We investigated using the modified McKenzie-Dandy operation for a patient with CD who failed selective peripheral denervation (SPD).

CASE DESCRIPTION

A 42-year-old man presented left-sided rotational torticollis for 3 years. He was referred for surgery after treating with a variety of oral medications and repeated botulinum toxin injections that became ineffective. For the first operation, the patient underwent SPD (modified Bertrand's operation); unfortunately, the postoperative outcome was unsatisfactory, and the operation was considered a failure. After his symptoms did not improve after 6 months, the modified McKenzie-Dandy operation was performed. Immediately following surgery, he experienced satisfactory outcomes. He was able to resume his normal activities and employment after 1 month after recovering from his temporary swallowing difficulties. He only complained of minor neck pain and no recurrence was observed after 3 years follow-up.

CONCLUSION

For patients who have failed SPD, a modified McKenzie-Dandy procedure is a feasible and effective option. The procedure is relatively safe when performed properly, and the long-term effects can be maintained.

Pain in cervical dystonia: mechanisms, assessment and treatment

INTRODUCTION

In patients with cervical dystonia (CD), pain is a major contributor to disability and social isolation and is often the main reason patients seek treatment. Surveys evaluating patient perceptions of their CD symptoms consistently highlight pain as a troublesome and disabling feature of their condition with significant impact on daily life and work.

AREAS COVERED

In this article, the authors review the epidemiology, assessment, possible mechanisms and treatment of pain in CD, including a meta-analysis of randomized controlled trial data with abobotulinumtoxinA.

EXPERT OPINION

Mechanisms of pain in CD may be muscle-based and non-muscle based. Accumulating evidence suggests that non-muscle-based mechanisms (such as abnormal transmission and processing of nociceptive stimuli, dysfunction of descending pain inhibitory pathways as well as structural and network changes in the basal ganglia, cortex and other areas) may also contribute to pain in CD alongside prolonged muscle contraction. Chemodenervation with botulinum toxin is considered the first-line treatment for CD. Treatment with botulinum toxin is usually effective, but optimization of the injection parameters should include consideration of pain as a core symptom in addition to the motor problems.

Improvements in Nerve Dissection Surgery Methodology for Spasmodic Torticollis Treatment

Spasmodic torticollis is the most common focal dystonia and is characterized by aberrant involuntary contraction of muscles of the neck and shoulders, which greatly affects patients' quality of life. Consequently, patients with this condition often desire treatment to alleviate their symptoms. The common clinical treatments for spasmodic torticollis include interventions such as drug therapy, botulinum toxin injections, and surgery. Surgical treatment is feasible for patients who do not respond well to other treatments or who are resistant to drugs. The gradual improvement of surgeons' understanding of anatomy and the ongoing developments in surgical techniques since their advent in the 1640s have resulted in many innovative surgical approaches that have led to improvements in the treatment of spasmodic torticollis. Previously used surgical treatments that result in uncertain outcomes, various postoperative complications, and serious damage to motor functions of the head and neck have gradually been discontinued. Nerve dissection surgery is the most common surgical treatment for spasmodic torticollis. This article reviews existing research on nerve dissection surgery for the treatment of spasmodic torticollis and the history of its development, along with the advantages and disadvantages of various surgical improvements. This article aims to provide clinicians with practical advice.

Unilateral pallidotomy as a potential rescue therapy for cervical dystonia after unsatisfactory selective peripheral denervation

OBJECTIVE

Selective peripheral denervation (SPD) is a widely accepted surgery for medically refractory cervical dystonia (CD), but when SPD has failed, the available approaches are limited. The authors investigated the results from a cohort of CD patients treated with unilateral pallidotomy after unsatisfactory SPD.

METHODS

The authors retrospectively analyzed patients with primary CD who underwent unilateral pallidotomy after SPD between April 2007 and August 2019. The Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) was used to evaluate symptom severity before surgery, 7 days postsurgery, 3 months postsurgery, and at the last follow-up. TWSTRS subscores for disability and pain and the 24-item Craniocervical Dystonia Questionnaire (CDQ-24) were used to assess quality of life.

RESULTS

At a mean final follow-up of 5 years, TWSTRS severity subscores and total scores were significantly improved (n = 12, mean improvement 57.3% and 62.3%, respectively, p = 0.0022 and p = 0.0022), and 8 of 12 patients (66.7%) were characterized as responders (improvement ≥ 25%). Patients with rotation symptoms before pallidotomy showed greater improvement in TWSTRS severity subscores than those who did not (p = 0.049). The most common adverse event was mild upper-limb weakness (n = 3). Patients' quality of life was also improved.

CONCLUSIONS

Unilateral pallidotomy seems to offer an effective and safe option for patients with CD who have otherwise experienced limited benefits from SPD.

Modified McKenzie procedure for the treatment of fixed painful torticollis

Spasmodic torticollis is characterized by involuntary movements of the neck muscles. In this video, the authors present the case of a 48-year-old man with painful right-sided rotational torticollis with contributions from both the suboccipital and the left sternocleidomastoid (SCM) muscles. He underwent a suboccipital craniectomy and C1–2 laminectomy with selective denervation of bilateral suboccipital and left-sided SCM muscles (modified McKenzie procedure). At the 2-week follow-up, he showed significant improvement and was able to rotate his neck about 70° toward the midline. Surgical treatment of spasmodic torticollis focuses on interrupting the motor pathway responsible for head turning. The modified McKenzie procedure is valuable, especially when other therapies fail.

The video can be found here: https://youtu.be/TK-WybKnGJM

Quality of life in idiopathic dystonia: a systematic review

OBJECTIVE

Dystonia is characterised by sustained muscular contractions frequently producing repetitive, twisting and patterned movements. The primary aim of this systematic review was to establish how quality of life (QoL) is affected in idiopathic focal, multifocal and segmental dystonia. This review aimed to evaluate variations in QoL between different subtypes of dystonia, identify the determinants of QoL and assess the effects of different treatments on QoL.

METHODOLOGY

A systematic computer-based literature search was conducted using the PubMed database to search for papers on QoL in idiopathic focal, segmental, multifocal and generalized dystonia. We identified 75 studies meeting our inclusion criteria. Information was extracted regarding prevalence, demographics and response to treatment where indicated.

RESULTS

This review revealed QoL to be a significant yet often overlooked issue in idiopathic dystonia. Data consistently showed that dystonia has a negative effect on QoL in patients compared to healthy controls, when measured using disease-specific and generic QoL measures. The majority of studies (n = 25) involved patients with cervical dystonia, followed by benign-essential blepharospasm (n = 10). Along with the beneficial effect to the dystonia symptoms, treatment using Botulinum Toxin and Deep Brain Stimulation is also effective in improving overall QoL across the majority of subtypes.

CONCLUSION

The findings demonstrate that patients' QoL should routinely be assessed and monitored, as this may affect subsequent management. Further research will allow for more robust management of factors contributing to impaired QoL, aside from the physical defects found in dystonia.

Deep Brain Stimulation Versus Peripheral Denervation for Cervical Dystonia: A Systematic Review and Meta-Analysis

BACKGROUND

Cervical dystonia is a disabling medical condition that drastically decreases quality of life. Surgical treatment consists of peripheral nerve denervation procedures with or without myectomies or deep brain stimulation (DBS). The current objective was to compare the efficacy of peripheral denervation versus DBS in improving the severity of cervical dystonia through a systematic review and meta-analysis.

METHODS

A search of PubMed, MEDLINE, EMBASE, and Web of Science electronic databases was conducted in accordance with PRISMA guidelines. Preoperative and postoperative Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) total scores were used to generate standardized mean differences and 95% confidence intervals (CIs), which were combined in a random-effects model. Both mean percentage and absolute reduction in TWSTRS scores were calculated. Absolute reduction was used for forest plots.

RESULTS

Eighteen studies met the inclusion criteria, comprising 870 patients with 180 (21%) undergoing DBS and 690 (79%) undergoing peripheral denervation procedures. The mean follow-up time was 31.5 months (range, 12-38 months). In assessing the efficacy of each intervention, forest plots revealed significant absolute reduction in total postoperative TWSTRS scores for both peripheral denervation (standardized mean difference 1.54; 95% CI 1.42-1.66) and DBS (standardized mean difference 2.07; 95% CI 1.43-2.71). On subgroup analysis, DBS therapy was significantly associated with improvement in postoperative TWSTRS severity (standardized mean difference 2.08; 95% CI 1.66-2.50) and disability (standardized mean difference 2.12; 95% CI 1.57-2.68) but not pain (standardized mean difference 1.18; 95% CI 0.80-1.55).

CONCLUSIONS

Both peripheral denervation and DBS are associated with a significant reduction in absolute TWSTRS total score, with no significant difference in the magnitude of reduction observed between the 2 treatments. Further comparative data are needed to better evaluate the long-term results of both interventions.

Comparison of 2 Operative Methods for Treating Laterocollis and Torticollis Subtypes of Spasmodic Torticollis: Follow-Up of 121 Cases

OBJECTIVE

The aim of this study was to compare the effects and complications of microvascular decompression (MVD) and neurectomy of spinal accessory nerve in the treatment of laterocollis and torticollis subtypes spasmodic torticollis (ST).

METHODS

Clinical data were retrospectively collected from 121 patients with laterocollis and torticollis subtypes of ST from January 1, 2012 to January 1, 2016. Among all the patients, 80 were treated by MVD and 41 were treated by neurectomy of spinal accessory nerve. The effect of the surgery was evaluated by the reduction in the Toronto Western spasmodic torticollis rating scale total scores before and after the operation. The mean duration of the postoperative follow-up period was 18.7 months (range, 12-27 months).

RESULTS

At the final follow-up, the Toronto Western spasmodic torticollis rating scale total score in the MVD group and in the neurectomy group was lowered by 50.43% ± 20.3% and 30.23% ± 19.4%, respectively, compared with the preoperative status (P < 0.05). In the MVD group, 25 (31.25%) patients achieved excellent relief, 44 (55%) patients improved moderate spasm, and 11 (13.75%) showed no relief. In the neurectomy group, 6 (14.63%) patients improved with excellent outcome, 7 (17.07%) had moderate relief, and 28 (68.29%) had no relief. There was no mortality or severe complication postoperatively, with the exception of hoarseness, shoulder numbness, and weakness.

CONCLUSIONS

MVD for ST of laterocollis and torticollis subtypes can provide satisfactory and lasting improvements without nerve impairment. MVD is to be preferred to neurectomy of accessory nerve in treating ST of laterocollis and torticollis subtypes.

Unmet Needs in the Management of Cervical Dystonia

Cervical dystonia (CD) is a movement disorder which affects daily living of many patients. In clinical practice, several unmet treatment needs remain open. This article focuses on the four main aspects of treatment. We describe existing and emerging treatment approaches for CD, including botulinum toxin injections, surgical therapy, management of non-motor symptoms, and rehabilitation strategies. The unsolved issues regarding each of these treatments are identified and discussed, and possible future approaches and research lines are proposed.