Safety and efficacy of ultrasound-guided percutaneous thermal ablation in treating low-risk papillary thyroid microcarcinoma: A pilot and feasibility study

Management of low-risk papillary thyroid cancer. Minimally-invasive treatments dictate a further paradigm shift?

BACKGROUND

Current management options for PTMC include lobo-isthmectomy and active surveillance (AS). Recently, ultrasound-guided minimally invasive procedures (MITs) are offered as a nonsurgical therapy for PTMC because they do not require hospitalization and general anaesthesia, and do not result in loss of thyroid function or cosmetic damage. MITs are reported to consistently provide, mostly in large retrospective series of patients, a rapid, safe, and cost-effective way to eradicate low-risk thyroid malignancies. However, conclusive data from well-conducted prospective studies on the histologically-proven completeness of tumor ablation and the long-term clinical advantages versus AS are still lacking.

OBJECTIVES

This study aimed to evaluate the efficacy and safety of ultrasound-guided minimally invasive treatments (MITs) for PTMC in comparison to traditional surgical methods and active surveillance, and to assess their role in current clinical practice.

METHODS

A structured literature review was conducted using keywords related to PTMC, MIT, and comparative techniques. Studies were evaluated based on treatment modality, patient selection, follow-up duration, complication rates, and clinical outcomes.

RESULTS

MITs have shown promising results in the management of PTMC. These treatments offer several advantages over surgery, such as reduced use of surgical resources, lower costs, minimal work disruption, and fewer major complications. However, there are still limitations, including the need for long-term surveillance and the potential risk of incomplete tumor ablation.

CONCLUSIONS

MITs represent a promising non-surgical option for managing low-risk PTMC, especially for patients ineligible for or refusing surgery. Despite favorable outcomes, more robust prospective data are needed to confirm their long-term benefits and completeness of tumor ablation. Interdisciplinary discussions and thorough patient education on the advantages and limitations of MITs are crucial for informed decision-making.

Radiofrequency ablation for solitary T1N0M0 papillary thyroid carcinoma in the danger triangle area: a preliminary analysis

OBJECTIVES

To evaluate the feasibility, efficacy, and safety of radiofrequency ablation (RFA) for solitary T1N0M0 papillary thyroid carcinoma (PTC) in the danger triangle area.

METHODS

94 participants (mean age 44.45 ± 13.08; 73 females) with solitary T1N0M0 PTC in the danger triangle area who underwent percutaneous RFA at the hospital from January 2018 to April 2020 were retrospectively analyzed. Key ablation procedures included sufficient paratracheal fluid isolation, low-power, and short active tip (5 mm working electrode). Tumor size changes at different time points after RFA, technical success rates, tumor disappearance, disease progression, and complications were recorded and compared.

RESULTS

Contrast-enhanced ultrasonography revealed that complete tumor ablation was performed with a 100% success rate in these patients. Post-ablation, the maximum diameter and volume of the ablation zone increased at the first and third month (p < 0.001), followed by a gradual decrease in size, without significant difference by the 6th month. The tumor disappearance rate was 76.59% (72/94), with higher rates in the T1a group compared to the T1b group (80% [64/80] VS57.1% [8/14], p < 0.001). There were no local recurrences. The incidence of new lesions and LNM was 3.2% (3/94), limited to the T1a subgroup. Further ablation was successfully applied to all new lesions and LMN. Mild voice changes were the only complication, with a rate of 3.2% (3/94), resolved within 4 months after RFA.

CONCLUSIONS

Sufficient paratracheal fluid isolation combined with a low-power, short active tip radiofrequency ablation strategy is a safe and effective method for treating solitary T1N0M0 PTC in the danger triangle area.

Preoperative strain ultrasound elastography can predict occult central cervical lymph node metastasis in papillary thyroid cancer: a single-center retrospective study

Objective

To determine whether preoperative ultrasound elastography can predict occult central cervical lymph node metastasis (CCLNM) in patients with papillary thyroid cancer.

Methods

This retrospective study included 541 papillary thyroid cancer patients with clinically negative lymph nodes prior to surgery between July 2019 and December 2021. Based on whether CCLNM was present on postoperative pathology, patients were categorized as CCLNM (+) or CCLNM (-). Preoperative clinical data, conventional ultrasound features, and ultrasound elastography indices were compared between the groups. Univariate and multivariate logistic regression analysis were performed to identify the independent predictors of occult CCLNM.

Results

A total of 36.60% (198/541) patients had confirmed CCLNM, while 63.40% (343/541) did not. Tumor location, bilaterality, multifocality, echogenicity, margin, shape, vascularity, capsule contact, extrathyroidal extension, aspect ratio, and shear wave elasticity parameters were comparable between the groups (all P > 0.05). Univariate analysis showed statistically significant differences between the two groups in age, sex, tumor size, calcification, capsule invasion, and strain rates ratio in strain ultrasound elastography (all P < 0.05). In multivariate logistic regression analysis, the independent predictors of occult CCLNM were age (OR = 0.975, 95% CI = 0.959-0.991, P = 0.002), sex (OR = 1.886, 95% CI = 1.220-2.915, P = 0.004), tumor size (OR = 1.054, 95% CI = 1.014-1.097, P = 0.008), and strain rates ratio (OR = 1.178, 95% CI = 1.065-1.304, P = 0.002).

Conclusion

Preoperative strain ultrasound elastography can predict presence of occult CCLNM in papillary thyroid cancer patients and help clinicians select the appropriate treatment strategy.

Meta-Analysis of the Application Effect of Different Modalities of Thermal Ablation and Surgical Treatment in Papillary Thyroid Microcarcinoma

Background

Papillary thyroid microcarcinoma (PTMC) refers to papillary thyroid carcinoma (PTC) with a maximum diameter of 10 mm. Thermal ablation, including radiofrequency ablation (RFA), microwave ablation (MWA), and laser ablation (LA), has been applied in the treatment of benign thyroid nodules and captured extensive attention. At present, the application of thermal ablation in PTMC has been extensively reported, but outcomes such as volume reduction rate (VRR), complete remission rate (CRR), and adverse reaction rate (ARR) vary considerably. Therefore, this meta-analysis was performed to evaluate the safety and efficacy of different treatment methods of PTMC.

Methods

We did a systematic review and network meta-analysis. We searched PubMed, EMBase, and Cochrane-Library from the date of inception to January 10, 2022, to retrieve the VRR, CRR, and ARR of MWA, RFA, LA and surgical treatment of PTMC, and a meta-analysis was performed using the R meta-package. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated, and sensitivity analyses, cumulative meta-analyses, and publication bias were also performed. Relevant literature was retrieved with keywords; the eligible cohort studies were screened based on the established inclusion and exclusion criteria.

Results

A total of 1515 patients were included in the 12-month follow-up. The overall VRR was 86.25% (95% CI: 77.89, 94.60), and the VRR was RFA > WMA > LA, but the differences were not significant. A total of 1483 patients were included in the last follow-up. The overall VRR was 99.41% (95% CI: 99.11, 99.72), and the VRR was RFA > WMA > LA, but the differences were not significant. A total of 1622 patients showed complete remission at the last follow-up, and the overall CRR was 0.63 (95% CI: 0.46, 0.79). The CRR was RFA > LA > WMA, but the differences were not significant. A total of 1883 patients had adverse reactions at the last follow-up, and the overall ARR was 0.06 (95% CI: 0.03, 0.08). The ARR at the last follow-up was RFA = Surg < LA < WMA. The ARR of the RFA and Surg subgroups was significantly lower than that of the WMA subgroup.

Conclusions

Similar good efficacy and safety profiles were observed in WMA, RFA, LA, and surgical treatment in PTMC, among which RFA showed the best volume reduction, complete remission rate, and adverse reaction reduction. However, there is a slight bias in the limited literature included in this study, and we did not conduct or refer to mechanistic studies to confirm its specific mechanism of action. Clinicians are advised to use their discretion in the choice of treatment.

The American Association of Endocrine Surgeons Guidelines for the Definitive Surgical Management of Secondary and Tertiary Renal Hyperparathyroidism

OBJECTIVE

To develop evidence-based recommendations for safe, effective, and appropriate treatment of secondary (SHPT) and tertiary (THPT) renal hyperparathyroidism.

BACKGROUND

Hyperparathyroidism is common among patients with chronic kidney disease, end-stage kidney disease, and kidney transplant. The surgical management of SHPT and THPT is nuanced and requires a multidisciplinary approach. There are currently no clinical practice guidelines that address the surgical treatment of SHPT and THPT.

METHODS

Medical literature was reviewed from January 1, 1985 to present January 1, 2021 by a panel of 10 experts in SHPT and THPT. Recommendations using the best available evidence was constructed. The American College of Physicians grading system was used to determine levels of evidence. Recommendations were discussed to consensus. The American Association of Endocrine Surgeons membership reviewed and commented on preliminary drafts of the content.

RESULTS

These clinical guidelines present the epidemiology and pathophysiology of SHPT and THPT and provide recommendations for work-up and management of SHPT and THPT for all involved clinicians. It outlines the preoperative, intraoperative, and postoperative management of SHPT and THPT, as well as related definitions, operative techniques, morbidity, and outcomes. Specific topics include Pathogenesis and Epidemiology, Initial Evaluation, Imaging, Preoperative and Perioperative Care, Surgical Planning and Parathyroidectomy, Adjuncts and Approaches, Outcomes, and Reoperation.

CONCLUSIONS

Evidence-based guidelines were created to assist clinicians in the optimal management of secondary and tertiary renal hyperparathyroidism.

Research Review of Thermal Ablation in the Treatment of Papillary Thyroid Carcinoma

Background

Minimally invasive treatment of thyroid tumors has become increasingly common, but has mainly focused on benign thyroid tumors, whereas thermal ablation of thyroid cancer remains controversial. Clinical studies analyzing the efficacy of thermal ablation of papillary thyroid carcinoma (PTC) have been conducted in several countries to verify its safety. Here, we screened and reviewed recent studies on the efficacy and safety of thermal ablation of PTC as well as psychological assessment, patient prognosis, recurrence, and factors affecting ablation.

Summary

The most significant controversy surrounding ablative treatment of PTC centers on its effectiveness and safety, and >40 studies have been conducted to address this issue. The studies include papillary thyroid microcarcinoma (PTMC) and non-PTMC, single PTC and multiple PTC, and controlled studies of ablative therapy and surgical treatment. In general, ablation techniques can be carefully performed and promoted under certain conditions and with active follow-up of postoperative patients. Ablation is a promising alternative treatment especially in patients who are inoperable.

Conclusions

Clinical studies on PTC ablation have provided new perspectives on local treatment. However, because PTC grows very slowly, it is an indolent tumor; therefore, studies with larger sample sizes and extended post-procedure follow-ups are necessary to confirm the investigators’ hypotheses.

Economic effect between surgery and thermal ablation for patients with papillary thyroid microcarcinoma: a systemic review and meta-analysis

BACKGROUND

At present, there are still many controversies regarding the treatment of papillary thyroid microcarcinoma (PTMC). It is worth noting that thermal ablation has become a viable alternative for patients at high risk of surgery or those who wish to receive more active treatment than active surveillance.

OBJECTIVE

To investigate the economic benefits, efficacy, and safety of thermal ablation for patients with PTMC.

METHODS

We searched PubMed, Cochrane Library, Web of Science, and Embase for articles published from the database establishment to August 2021. All of the studies included were retrospective cohort analyses. In addition, meta-analysis was performed using the Stata15.1 versions and Review Manager5.3. Data were extracted according to the PRISMA guidelines by two professional doctors.

RESULTS

A total of 7 articles (1582 patients) were included in our systematic review and meta-analysis. We discovered that thermal ablation could shorten the hospitalization time (SMD, -3.82[95%CI, -5.25 to -2.40]), operation time (SMD, -5.67[95%CI, -6.65 to -4.68]), cost (SMD, -3.40 [95%CI, -5.06 to -1.75]) and reduce postoperative complications (OR, 0.07 [95%CI, 0.01 to 0.44]) than surgical treatment. In addition, our study also found that compared with surgery, there was no significant difference in the recurrence rate (OR, 1.53 [95% CI, 0.63 to 3.73]) and metastasis rate (OR, 0.47 [95% CI, 0.12 to 1.86]).

CONCLUSION

On the premise of being safe and effective, thermal ablation has better economic benefits than surgical treatment for patients with PTMC.

Effect of Hashimoto's thyroiditis on the extent of the ablation zone in early stages of ultrasound-guided radiofrequency ablation for papillary thyroid microcarcinoma: a large cohort study of 772 patients

PURPOSE

To evaluate the effect of Hashimoto's thyroiditis (HT) on the extent of ablation zone in ultrasound (US)-guided radiofrequency ablation (RFA) for early stages of papillary thyroid microcarcinoma (PTMC).

METHOD

We selected 772 patients with 797 PTMCs who underwent with RFA from August 2017 to August 2020. They were subdivided into two groups as follows: (i) 216 patients (224 PTMCs) with HT in the 'HT + PTMC' group and (ii) 556 patients (573 PTMCs) with healthy thyroid in the 'PTMC' group. We assessed the extent (maximum diameter and volume) of the ablation zone by contrast-enhanced ultrasound (CEUS) immediately, one day, and 1 week following RFA.

RESULTS

The ablation zone of the 'HT + PTMC' group was smaller than that of the 'PTMC' group at 1 week of RFA (maximum diameter: 14.6 ± 3.1 mm vs. 15.2 ± 3.2 mm and volume: 0.932 ± 0.498 mL vs. 1.028 ± 0.540 mL, respectively, p < .05). However, there were no differences before, immediately, and one day post-RFA (p > .05). Life-threatening complications did not develop in any of the patients.

CONCLUSION

RFA-treated PTMCs were smaller in size in patients with HT than in those with a healthy thyroid at 1 week of RFA. However, the exact mechanism underlying this phenomenon and its clinical significance warrant further investigation.

The feasibility and efficacy of ultrasound-guided percutaneous laser ablation for multifocal papillary thyroid microcarcinoma

OBJECTIVE

The aim of this study was to evaluate the feasibility and efficacy of percutaneous laser ablation (PLA) for patients with multifocal papillary thyroid microcarcinoma (PTMC).

MATERIALS AND METHODS

A cohort of patients who underwent ultrasound (US)-guided PLA for primary PTMC were enrolled in this study. The patients were divided into a multifocal PTMC (multi-PTMC) group and a unifocal PTMC (uni-PTMC) group. Before PLA, conventional US and contrast-enhanced ultrasound (CEUS) were performed to evaluate the PTMC and cervical lymph nodes. The operation time, energy, power, amount of isolation liquid, and complications during PLA were recorded. Patients were followed up at 2 days, 1 month, 3 months, and 6 months, and every 6 months after that. Volume reduction rate (VRR), local tumor recurrence, and lymph node metastasis after PLA were observed.

RESULTS

The study included 12 patients with 26 PTMCs and 60 patients with 60 PTMCs. The operation time, total energy, and amount of isolation liquid in the multi-PTMC group were more than those in the uni-PTMC group (p = 0.000, 0.007, and 0.020, respectively). The mean follow-up durations in multi-PTMC and uni-PTMC groups were 19.75 ± 11.46 months (6-36 months) and 16.33 ± 10.01 months (4-40 months), with a similar VRR of the ablated lesions in the two groups. One and three cases with newly developed PTMCs were observed in the multi-PTMC group and the uni-PTMC group during follow-up, respectively. There was no regrowth of treated lesions, lymph node metastasis, or distant metastasis. At the end of the follow-up, all the ablated lesions in the two groups completely disappeared or only remained scar strips.

CONCLUSION

PLA is a safe and effective technique for treating multifocal PTMC, which might be an alternative technique for patients who are not eligible or are unwilling to undergo surgery.

Analysis and evaluation of the efficacy of ultrasound-guided microwave ablation for papillary thyroid microcarcinoma

OBJECTIVE

The choice of the most appropriate therapeutic approach for a diagnosed papillary thyroid microcarcinoma (PTMC) remains controversial. The present study aimed to evaluate the efficacy of microwave ablation (MWA) for unifocal PTMC with a diameter of ≤0.6 cm.

METHODS

A total of 63 consecutive patients with PTMC treated with MWA were studied retrospectively. MWA was performed using the hydrodissection technique and multidimensional fixed-needle principle. We analyzed the absorption of the MWA area and evaluated the prognosis over a follow-up period of 24 months. In addition, 83 patients with PTMC who underwent surgery were selected. The operating room characteristics and procedural complications of the two groups were compared.

RESULTS

In the MWA group, the volume of nodules (p < 0.05) decreased from 0.04 ± 0.03 cm³ to 0.0001 ± 0.0004 cm³ at the 24-month follow-up after MWA, and the volume reduction rate (p < 0.05) was 99.43 ± 1.58%. The incidence of temporary reactive hyperplastic lymphadenectasis was higher and that of other complications was lower in the MWA group than in the surgery group. One percent of the patients in the surgery group had recurrence or metastasis, but none were detected in the MWA group. The loss of thyroid tissue volume (p < 0.001), operating room time (p < 0.001), and the mean length of hospital stay (p < 0.001) were significantly lower in the MWA group than in the surgery group.

CONCLUSION

Ultrasound-guided MWA is an effective treatment strategy for unifocal PTMC with a diameter of ≤0.6 cm.

A feasibility study of microwave ablation for papillary thyroid cancer close to the thyroid capsule

BACKGROUND

To evaluate the feasibility, efficiency, and safety of microwave ablation (MWA) for papillary thyroid carcinoma (PTC) close to the thyroid capsule.

METHODS

The data of 106 cases who underwent thermal ablation from June 2014 to September 2020 were retrospectively analyzed. The mean follow-up time was 25 ± 11 months (range, 9-48 months). The strategy of fluid isolation was successfully applied in all cases, and all PTC nodules underwent extended ablation. The technical feasibility, technical success rate, and safety were analyzed. Changes in tumor size at different time points after MWA were evaluated.

RESULTS

According to the contrast-enhanced ultrasound results after ablation, MWA has been successfully applied in all enrolled cases. The capsular ablation has also been achieved for all cases. Nodules in 71 cases (70.0%) completely disappeared in the follow-up period. No local recurrence was detected. The incidence of lymph node metastasis and new tumors was 1.9% (2/106) respectively. Light voice changes were the only complication, with a rate of 5.7% (6/106), which were relieved within 6 months after MWA. The size of the ablation zone increased firstly in 6 months after MWA compared with the pretreatment tumor size (p < 0.05). At 12, 18, 24, 30, 36 and 42 months after MWA, the ablation zone shrank and the sizes were smaller than the tumor size before MWA (p < 0.05 for all).

CONCLUSIONS

MWA is an effective, safe, and feasible method in treating PTC close to the thyroid capsule.

Heating technology for malignant tumors: a review

The therapeutic application of heat is very effective in cancer treatment. Both hyperthermia, i.e., heating to 39-45 °C to induce sensitization to radiotherapy and chemotherapy, and thermal ablation, where temperatures beyond 50 °C destroy tumor cells directly are frequently applied in the clinic. Achievement of an effective treatment requires high quality heating equipment, precise thermal dosimetry, and adequate quality assurance. Several types of devices, antennas and heating or power delivery systems have been proposed and developed in recent decades. These vary considerably in technique, heating depth, ability to focus, and in the size of the heating focus. Clinically used heating techniques involve electromagnetic and ultrasonic heating, hyperthermic perfusion and conductive heating. Depending on clinical objectives and available technology, thermal therapies can be subdivided into three broad categories: local, locoregional, or whole body heating. Clinically used local heating techniques include interstitial hyperthermia and ablation, high intensity focused ultrasound (HIFU), scanned focused ultrasound (SFUS), electroporation, nanoparticle heating, intraluminal heating and superficial heating. Locoregional heating techniques include phased array systems, capacitive systems and isolated perfusion. Whole body techniques focus on prevention of heat loss supplemented with energy deposition in the body, e.g., by infrared radiation. This review presents an overview of clinical hyperthermia and ablation devices used for local, locoregional, and whole body therapy. Proven and experimental clinical applications of thermal ablation and hyperthermia are listed. Methods for temperature measurement and the role of treatment planning to control treatments are discussed briefly, as well as future perspectives for heating technology for the treatment of tumors.

European Thyroid Association and Cardiovascular and Interventional Radiological Society of Europe 2021 Clinical Practice Guideline for the Use of Minimally Invasive Treatments in Malignant Thyroid Lesions

The growing detection of papillary thyroid microcarcinomas (PTMCs) is paralleled by an increase in surgical procedures. Due to the frequent indolent nature, cost, and risk of surgery, active surveillance (AS) and ultrasound-guided minimally invasive treatments (MITs) are in suitable cases of incidental PTMC proposed as alternatives to thyroidectomy. Surgery and radioiodine are the established treatments for relapsing cervical differentiated thyroid carcinoma (DTC) metastases. But radioiodine refractoriness, risk of surgical complications, adverse influence on quality of life, or declining repeat surgery have led to AS and MIT being considered as alternatives for slow-growing DTC nodal metastases. Also, for distant radioiodine-refractory metastases not amenable to surgery, MIT is proposed as part of a multimodality therapeutic approach. The European Thyroid Association and the Cardiovascular and Interventional Radiological Society of Europe commissioned these guidelines for the appropriate use of MIT. Based on a systematic PubMed search, an evidence-based approach was applied, and both knowledge and practical experience of the panelists were incorporated to develop the manuscript and the specific recommendations. We recommend that when weighing between surgery, radioiodine, AS, or MIT for DTC, a multidisciplinary team including members with expertise in interventional radiology assess the demographic, clinical, histological, and imaging characteristics for appropriate selection of patients eligible for MIT. Consider TA in low-risk PTMC patients who are at surgical risk, have short life expectancy, relevant comorbidities, or are unwilling to undergo surgery or AS. As laser ablation, radiofrequency ablation, and microwave ablation are similarly safe and effective thermal ablation (TA) techniques, the choice should be based on the specific competences and resources of the centers. Use of ethanol ablation and high-intensity focused ultrasound is not recommended for PTMC treatment. Consider MIT as an alternative to surgical neck dissection in patients with radioiodine refractory cervical recurrences who are at surgical risk or decline further surgery. Factors that favor MIT are previous neck dissection, presence of surgical complications, small size metastases, and <4 involved latero-cervical lymph nodes. Consider TA among treatment options in patients with unresectable oligometastatic or oligoprogressive distant metastases to achieve local tumor control or pain palliation. Consider TA, in combination with bone consolidation and external beam radiation therapy, as a treatment option for painful bone metastases not amenable to other established treatments.

Efficacy and Safety of Thermal Ablation for Solitary T1bN0M0 Papillary Thyroid Carcinoma: A Multicenter Study

BACKGROUND

Ultrasound-guided thermal ablation plays an important role in the management of thyroid disease. The objective of this study was to evaluate the feasibility, efficacy, and safety of thermal ablation for patients with solitary T1bN0M0 papillary thyroid carcinoma (PTC) who are ineligible for or unwilling to undergo surgery.

MATERIALS AND METHODS

Data pertaining to 172 patients (38 males and 134 females) who received thermal ablation therapy at 12 hospitals between April 2015 and March 2020 were retrospectively analyzed. The mean duration of follow-up was 24.9 ± 14.1 months (range, 12-60). The technical feasibility, technical success, efficacy, and safety of treatment were analyzed. Postablation tumor size at various time points was compared with preablation measurement.

RESULTS

All patients selected for thermal ablation received enlarged ablation, according to contrast-enhanced ultrasound postablation. The maximum diameter and volume of ablation zone at 6, 12, 18, 24, 36, and 48 months postablation were significantly smaller than those recorded preablation (P < 0.05 for all). At the most recent follow-up, 106 (61.6%) tumors had completely disappeared. The rate of lymph node metastasis was 0.6% (1/172) and the incidence of new tumors was 1.2% (2/172). The overall complication rate was 5.2% (9/172) (major complications: 4.6% [8/172]; minor complications: 0.6% [1/172]). All major complications were relieved within 4 months postablation.

CONCLUSION

Thermal ablation may be a feasible, effective, and safe treatment option for patients with solitary T1bN0M0 PTC who are ineligible for or unwilling to undergo surgery. It may provide a novel treatment option for selected patients.

Clinical management of low-risk papillary thyroid microcarcinoma

Papillary thyroid microcarcinoma (PTMC) is well known to have an indolent nature with an excellent prognosis. Surgery has been the standard treatment during the past several decades, with metastasis or recurrence being exceedingly rare. Active surveillance (AS) is a new risk-adapted approach alternative to surgery that involves just watching, but not giving any treatment unless needed, not addressing the tumor itself. The patients for whom AS is adopted spend their time "with tumors." In follow-up, it is possible that alarming factors such as tumor progression appear, causing anxiety about progression. Furthermore, endless follow-up is needed. However, considering the indolent nature and unfavorable events such as surgical complications caused by surgery, AS is a good management plan for selected PTMC patients. Decision making balancing between the prognosis and unfavorable events is needed for the treatment plan. Consideration of the factors and timing of surgical conversion is also needed. In this review article, how AS should be adopted as a new management option that is an alternative to surgery, which has been the absolute choice of treatment up to recently, is discussed. Concurrently, the characteristics of the two treatment strategies are reviewed, while introducing the background that explains how AS came to attention.

Coagulation of posterior cricoarytenoid muscles for abduction spasmodic dysphonia

INTRODUCTION

Spasmodic dysphonia (SD), a form of focal dystonia, has been defined as a neurogenic, task-specific disorder characterized by abrupt spasms of intrinsic laryngeal muscles that result in phonatory breaks. There are three classic types of SD: adductor SD, abductor (ABSD) and mixed SD. Compared with the more common adductor form, treatment of ABSD with botulinum toxin injection is related to a shorter efficacy and improvement in only about 70% of patients [Blitzer et al. in Laryngoscope 108:1435-1441, 1998]. Moreover, due to the possible loss of efficacy over time or patient refusal for repeated injections, surgical solutions for permanent or at least long-term results must be considered.

METHOD

The surgical technique we propose is based on transoral bilateral posterior cricoarytenoid muscle (PCA) coagulation by radiofrequency (Celon, pro surg 250-T30, Olympus, Germany, 10 W, in 3 spots, each side) under a microscope or rigid scope control. The procedure is performed in two sessions distant of 2-3 weeks to avoid the risk of bilateral vocal fold temporary paralysis in adduction. A 52-year-old female patient with no audible voicing, resistant to botulinum toxin and after failure of relaxation thyroplasty type III according to lssihki [Saito et al. in Case Rep Otolaryngol 2018:4280381, 2018] showed an improvement of the Voice Handicap Index (VHI-10) from 35/40 to 19/40. The patient was rated G2R3B2A1S2 according to GRABS scale.

CONCLUSION

PCA coagulation for ABSD is a safe and reusable surgical option. It is less invasive than other techniques described before. To the best of our knowledge, this technique was never reported before in this type of SD.