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Year : 2021  |  Volume : 65  |  Issue : 13  |  Page : 51-53  

Clinical pearls in anaesthesia for electromyographic tube guided robotic thyroidectomy

Department of Anaesthesia, Rajiv Gandhi Cancer Institute and Research Centre, Sector-5, Rohini, Delhi, India

Date of Submission19-Apr-2020
Date of Decision11-Jul-2020
Date of Acceptance27-Sep-2020
Date of Web Publication20-Mar-2021

Correspondence Address:
Shagun Bhatia Shah
H. No. 174-175, Ground Floor, Pocket-17, Sector -24, Rohini, Delhi - 110 085
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ija.IJA_402_20

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How to cite this article:
Shah SB, Dubey JK, Bhardwaj M, Mittal A. Clinical pearls in anaesthesia for electromyographic tube guided robotic thyroidectomy. Indian J Anaesth 2021;65:51-3

How to cite this URL:
Shah SB, Dubey JK, Bhardwaj M, Mittal A. Clinical pearls in anaesthesia for electromyographic tube guided robotic thyroidectomy. Indian J Anaesth [serial online] 2021 [cited 2021 Apr 10];65:51-3. Available from: https://www.ijaweb.org/text.asp?2021/65/13/51/311601


The novel gasless-technique of robot-assisted transaxillary thyroid surgery (RATS) involves introducing robotic instruments via an axillary-incision through a surgically-created tunnel to access the thyroid gland, avoiding ugly cervical-scars. RATS, with intra-operative electromyography-guided dissection has conflicting requirements. A fundamental requisite of robot-assisted surgery is avoiding catastrophic patient movement with robotic-arms docked, usually achieved by a very deep neuromuscular blockade (NMB). Contrarily, effective intraoperative vocalis-muscle electromyography for recurrent laryngeal nerve (RLN) function requires abolishing NMB, making RATS a muscle-relaxant sparing surgery. Cosmesis provided by a smaller/occult scar (hallmark of RATS) becomes meaningless if iatrogenic mouth-deviation/hoarseness of voice/respiratory distress occur.[1],[2] The quest to find RLN-preservation techniques is the holy grail of thyroid surgery. The incidence of bilateral RLN-palsy in total thyroidectomies employing intraoperative neuromuscular monitoring (IONM) is 2.43% versus 5.18% without IONM.[2] Continuous IONM, potentially facilitates changing surgical strategy before irreversible RLN-damage (loss of signal/amplitude-reduction below 100 μV at 2–3 mA stimulation).[3]

Nerve-integrity monitoring (NIM) electromyographic (EMG) endotracheal tube (Medtronic® Xomed, Inc, Jacksonville, USA)[4] is a special soft-silicone, flexometallic-tube with integrated stainless-steel bipolar contact-electrodes and audiovisual alarms, said to be useful for IONM. We report here its use in a three-patient case series.

Our modified anaesthesia-circuit comprised of two conventional circle-systems connected end-to-end to access the anaesthesia-workstation displaced to the patient's foot-end. The operation table was rotated 180° to accommodate the robot at patient's head-end [Figure 1]. Our first patient was a 27-year-old lady with a left retro-auricular approach for thyroidectomy and inter-mammary grounding-needle-electrode placement. A light NMB (maintaining two twitches out of train-of-four with atracurium infusion) was maintained throughout surgery lasting 7 h, but even this produced a 'false-low' EMG-signal. In our subsequent two patients, RATS was performed without using any additional NMB after the intubation-dose. Anaesthetic management of our second patient served as a prototype for our third patient. Both surgeries lasted 6 h.
Figure 1: Electromyography (EMG) Tube, NIM Neuro-3 EMG monitor screen, patient positioning and circuit modification and intra-operative image of robot.assisted trans-axillary thyroid surgery (RATS) in progress

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Our second patient was a 34-year-old, 62-kg lady with papillary carcinoma necessitating total thyroidectomy. After standard-monitoring application, anaesthesia was induced using intravenous (IV) midazolam 1 mg, fentanyl 100 μg, propofol 70 mg, followed by atracurium 50 mg. C-Mac D-blade videolaryngoscope-guided endotracheal intubation with EMG-tube (7 mm internal diameter) was performed. The ribbon-strip emerging from the four sensing surface-electrodes was taped at two points to the EMG-tube shaft to prevent soiling, dislodgement and glottic-view obliteration. We etched a thick black-line, three-quarter distance up the patient-end of electrode-cuff, connecting bilateral anterior electrodes. Mid-glottic positioning of electromyographic sensors in optimal contact with vocal cords, (sans axial-rotation of EMG-tube) was videolaryngoscopically ensured by keeping this black-line in midline. After auscultatory and capnographic confirmation of EMG-tube placement and neck-extension, EMG-tube integrity and supracarinal-positioning was ascertained via a fibreoptic bronchoscope. Intraoperative fibreoptic bronchoscopy ruled out EMG-tube inner wall dissection/collapse. Laryngofibrescopy affirmed glottic-contact of surface electrodes post-positioning. The position was supine (arms abducted 90°; elbows flexed). Two grounding needle-electrodes were placed over right clavicle away from the subclavicular tunnelling-track. Bispectral-index-guided (BIS 40-45) dexmedetomidine infusion, sevoflurane, nitrous oxide and fentanyl boluses maintained adequate anaesthetic-depth. Bilateral thyroid-lobes were accessed via a right-axillary incision. Four additional ports (for robotic-arms; camera) produced total 5 cm-sized incisions, all below the neckline. Bilateral vocal-cord movement was videolaryngoscopically visualised on tracheal-extubation in all three patients. Phonatory vocal-cord movement was later checked by point-of-care ultrasound.[5]

Since any type/dose of muscle relaxant hampers RLN-monitoring,[4] to variable/unpredictable extents, RATS can be performed without NMB in these special circumstances. NMB conveniently wears off, while surgeons perform painting, draping, tunnelling and robotic-docking. Consequently, vocalis-muscle activity can readily be intraoperatively tested when surgeons approach the thyroid gland. Suboptimal tube-position, NMB, lubricating jelly, salivary-pooling and loose monitor/interface-box connections produce false-negative responses.

Subcutaneous ropivacaine infiltration (along tunnelled-path), IVmorphine-based patient-controlled analgesia and IVparacetamol (1 g; 12-hourly) sufficed as multimodal postoperative analgesia.

None of our patients developed postoperative brachial plexus/vocal cord palsy/paresis.

EMG-tubes are sometimes reused after disinfection as a cost-cutting measure which can produce inner-wall dissection aggravated by nitrous oxide. Catastrophic cuff-herniation, inward-collapse of EMG-tube wall (with life-threatening airway obstruction/raised airway pressures), and lightwand-induced electrode dislodgement causing cuff-damage are reported complications.[6],[7] Avoiding reuse, ribbon-strip taping and intraoperative fibreoptic bronchoscopy served as simple precautions enabling successful EMG-tube use in our RATS patients.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

   References Top

Shah SB, Hariharan U, Kulkarni A, Dabas NC. Anaesthesia for robotic thyroidectomy for thyroid cancer and review of literature. Indian J Anaesth 2016;60:55-7.  Back to cited text no. 1
[PUBMED]  [Full text]  
Pardal-Refoyo JL, Ochoa-Sangrador C. Bilateral recurrent laryngeal nerve injury in total thyroidectomy with or without intraoperative neuromonitoring. Systematic review and meta-analysis. Acta Otorrinolaringol Esp 2016;67:66-74.  Back to cited text no. 2
Périé S, Santini J, Kim HY, Dralle H, Randolph GW. International consensus (ICON) on comprehensive management of the laryngeal nerves risks during thyroid surgery. Eur Ann Otorhinolaryngol, Head Neck Dis 2018;135:7-10.  Back to cited text no. 3
Martín JJ, Tamarit MC, Escudero MT, Solaz CR. Monitoring of recurrent laryngeal nerve injury using an electromyographic endotracheal tube in thyroid and parathyroid surgery. Anesthetic aspects. Rev Esp Anestesiol Reanim 2013;60:576-83.  Back to cited text no. 4
Kumar A, Sinha C, Kumar A, Singh AK, Vardhan H, Bhavana K, Bhar D. Assessment of functionality of vocal cords using ultrasound before and after thyroid surgery: An observational study. Indian J Anaesth 2018;62:599-602.  Back to cited text no. 5
[PUBMED]  [Full text]  
Vera-Sanchez MB, Quintana-Villamandos B. Medtronic electromyographic tracheal tube. Anaesthesia 2017;72:1282-3.  Back to cited text no. 6
Kim HS, Park KS, Kang MH, Park CD. Damage to the cuff of EMG tube at endotracheal intubation by using a lightwand-A case report. Korean J Anesthesiol 2010;59:17-20.  Back to cited text no. 7


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