THYROIDVolume 4, Number 4, 1994Mary Ann Liebert, Inc., Publishers

Thyroid Surgery Using Monitored Anesthesia Care: AnAlternative to General Anesthesia

PAUL LO GERFO, BETH ANN DITKOFF, JOHN CHABOT, and CARL FEIND

ABSTRACT

Forty consecutive patients undergoing thyroid surgery under local anesthesia (LA) by a single surgeon over a 5-yearperiod were included in this retrospective review. In all cases, the indication for LA was patient request. The study in-cluded 29 females and 11 males with an average age of 44 years (range 22-66 years). Body habitus was thin in 12.5%,average in 67.5%, and obese in 20%. Operations consisted of 21 unilateral thyroid lobectomies, 3 partial thyroidec-tomies, 3 subtotal thyroidectomies, and 13 total thyroidectomies. The pathology revealed benign disease in 45% andmalignant disease in 55%. All procedures were performed using lidocaine and/or bupivacaine to administer a deepcervical plexus block as well as a field block.Mild additional intraoperative intravenous sedation was provided in mostcases. Two patients were converted emergently to general endotracheal anesthesia because of inability to tolerate LAin one and a seizure secondary to intraarterial injection of lidocaine in the other patient. There were no instances ofwound infection hemorrhage, recurrent laryngeal nerve injury, or hypoparathyroidism. In conclusion, thyroidsurgery in selected patients can be performed safely using LA by experienced surgeons. Ifpatients are carefully pre-pared preoperatively, LA offers a simple and reasonable alternative to general anesthesia.

INTRODUCTION

General anesthesia is used for most thyroid surgery in theUnited States today. Historically, however, thyroid surgery

was performed under local anesthesia. Recently, there has been arenewed interest in this technique because of patient preferenceand emphasis on outpatient and short stay surgery (1).After several reports in the European literature describing the

role of local anesthesia in thyroid surgery (2^1), two small serieswere published in the United States. The first report, by Saxe etal., reviewed 17 patients who underwent either thyroid or

parathyroid surgery using local anesthesia (5). The indicationsfor local anesthesia included patient preference and/or con-traindication to general anesthesia, such as severe cardiac or pul-monary disease. The authors report two complications as a resultof this technique. One patient suffered an arrythmia thought tobe secondary to the choice of anesthetic agent. The second pa-tient experienced respiratory distress after vocal cord paralysiscaused by infiltration of the local anesthesia into the vagusnerve.

A second study performed by Hochman and Fee reviewed 21thyroidectomies performed under local anesthesia (6). The indi-cations for local anesthesia were similar to Saxe's study. Sixteen

hemithyroidectomies and five total thyroidectomies under localanesthesia were compared to 22 matched thyroid surgeries per-formed under general anesthesia. The authors found similarcomplication rates occurred in both groups of patients, specifi-cally transient hypocalcemia, transient vocal cord paralysis,hematoma, seroma, and wound infection.

These reports have encouraged the use of local anesthesia forthyroid surgery in appropriately chosen patients. The currentstudy is the largest series in the United States literature reportingthe outcome of thyroid and parathyroid surgery using regionalanesthetic agents. This report also details the technique andanatomical landmarks involved in regional cervical plexusblock.

MATERIALS AND METHODS

Forty patients undergoing thyroid surgery from 6/88 to 8/93under local anesthesia were included in this retrospective chartreview study. In all instances, the indication for local anesthesiawas patient request. All patients had their surgery performed bya single senior surgeon (P.L.) at Columbia-PresbyterianMedicalCenter. A general surgery resident, usually postgraduate year

Department of Surgery, Columbia University College of Physicians and Surgeons, New York, New York.

437

438 LO GERFO ET AL.

three or four, served as the first assistant. Local anesthesia was

administered by the senior surgeon in all cases. An anesthesiateam consisting of a resident supervised by an attending pro-vided perioperative monitoring as well as intraoperative seda-tion.

In all cases, Xylocaine (lidocaine hydrochloride 0.5% withoutepinephrine, Astra Pharmaceutical, Westboro, MA) was admin-istered as the primary local anesthetic agent. The dose of lido-caine was near the maximal recommended dosage according tothe manufacturer's instructions, usually about 300 mg per pa-tient, but never exceeding 4.5 mg/kg. Occasionally Marcaine(bupivacaine hydrochloride 0.25% without epinephrine,Winthrop Pharmaceuticals, New York, NY) was added near theend of the operation (usually approximately 40 mg) to provide a

longer postoperative period of pain relief.The success of performing thyroid surgery under local anes-

thesia is dependent on the efficacy of the deep cervical plexusblock (7,8). Knowledge of the anatomy of the cervical spinalnerves (C2-C4) as they exit from the foramina of the cervicalvertebrae is essential. Each nerve traverses the groove in thetransverse process of these vertebrae. Branches of the cervicalplexus emerge at the middle border of the sternocleidomastoidmuscle. The anatomic landmarks include the tip of the mastoidprocess, the cricoid cartilage, and the lower border of themandible (Fig. 1).

The patient is placed in the supine position with the head in a

neutral position and the arms at rest by the side. Using a 22-gauge needle, 15 mL of anesthetic agent are injected into the su-

perior, medial border of the sternocleidomastoid muscle at thelevel of the ramus of the mandible, approximately 2-3 cm belowthe mastoid process. The needle should be directed in a superiorangle. An additional 15 mL of anesthetic agent is then injectedalong the anterior border of the sternocleidomastoid muscle un-

til the inferior border of the thyroid is reached.Complications of the cervical plexus block include intraarter-

ial injection into the vertebral artery and infiltration of thephrenic nerve with resulting respiratory embarrassment. The

Table 1. Type and Length of Surgery

Injection site

Cricoid cartilage N—-'

FIG. 1. Landmarks for regional anesthesia.

OperationNumber ofpatients

Meanduration inminutes(range)

Unilateral thyroid lobectomy 21 71 (45-125)Partial thyroidectomy 3 45 (35-60)Subtotal thyroidectomy 3 97 (45-135)Total thyroidectomy 13 107 (75-195)

Total number of patients 40

first complication can be avoided by aspirating the syringe be-fore injecting, and the second complication can be prevented byinjecting superiorly at the C2-C3 level and not attempting toblock C4 or lower.

After the deep cervical plexus block has been accomplished, afield block is performed using the remaining Xylocaine and a

25-gauge needle in the region of the anterior neck. Care is usedto infiltrate the subcutaneous tissues only and not the dermis inorder to avoid a painful burning sensation. If the block is done 15min before the surgery begins, sufficient time is allowed for theanesthetic to diffuse into the dermis. During the operation, afterthe thyroid has been exposed, an additional 1 mL of anestheticagent is used to infiltrate the region near the superior thyroidartery.

RESULTS

All 40 charts were available for review.

Patient characteristics

The study included 29 females and 11 males with an averagemean age of 44 years and an age range from 22 to 66 years. Bodyhabitus, based on height and weight, was divided into three cate-

gories: thin, average, and obese, based on the PresbyterianHospital diet manual developed from the Fogarty InternationalConference on Obesity and the Table of the Metropolitan LifeInsurance Company (9). Twenty-seven of 40 patients (67.5%)were considered in the average weight range, while five (12.5%)patients were thin and eight patients (20%) were consideredobese.

Of special note, one patient included in the study was deaf,and a medically trained sign-language interpreter was employedto assist with communication during the operation.

SurgeryThe operations and length of surgery performed are outlined

in Table 1. Eighteen patients had surgery for benign disease andthe remaining 22 patients had a diagnosis of thyroid malignancy.

Perioperative anesthesia

Physical status was assessed using the American Society ofAnesthesiologists' classification (10). Eighteen patients were

characterized as Class I (45%), 20 (50%) Class II, and 2 (5%)

THYROID SURGERY USING MONITORED ANESTHESIA 439

Class III. Information regarding preoperative sedation wasavailable for 39 of 40 patients. Only one patient received preop-erative sedation, which consisted of 10 mg diazepam adminis-tered by mouth. Intraoperative sedation was provided by a com-

bination of intravenous drugs, usually midazolam and fentanyl,but also sometimes included morphine, propofol, or pentothal.In two instances, patients received supplemental anesthesia withnitrous oxide for part of the operation. In all instances, patientswere cooperative and able to respond to questions and directionsappropriately. The surgeons' goal was to produce conscious se-

dation.

Duration of hospital stayAll patients were discharged home by the second postopera-

tive day.

ComplicationsTwo patients in this series of 40 (5%) had complications as a

result of anesthetic choice.One patient, a 36-year-old, thin, Class III woman who was un-

dergoing total thyroidectomy lobectomy experienced a seizuresecondary to an intraarterial injection of lidocaine. This patientwas converted emergently to general endotracheal anesthesia.Total operating time was 135 min. No adverse postoperative se-

quelae were encountered as a result of the seizure or the conver-sion to general anesthesia.

The second complication involved a 56-year-old averageweight woman, Class II, undergoing thyroid lobectomy for a

thyroid cancer. This patient was an opera singer and because theoperation was lengthened by the need to carefully trace the supe-rior laryngeal nerve, supplemental mask general anesthesia wasadministered using isoforane throughout the majority of thecase. Total operating time was 90 min.

There were no instances of either temporary or permanent re-current laryngeal nerve injury or hypoparathyroidism. In addi-tion, there were no cases of postoperative wound infection or

hemorrhage.

DISCUSSION

Local anesthesia provides a simple and safe alternative to pa-tients who need to undergo thyroid surgery, but do not desiregeneral anesthesia. If patients are cooperative and the cervicalblock is effective, most people experience minimal discomfort.Too much sedation should be avoided; it is essential to securepatient cooperation during the procedure. For example, this co-

operation is helpful in assessing the voice intraoperatively. It isalso important to prepare the patient with careful preoperativecounseling, including education regarding patient positioning,length of the procedure, and expectation of intraoperative sensa-tions. For this last point, it is helpful to gently place pressure onthe patient's trachea while he or she is lying on the examiningtable in order to mimic the sensation of intraoperative retraction.

The patient characteristics, type of operation, length ofsurgery, and physical status were comparable to patients under-going thyroid surgery under general anesthesia during the same5-year time period. In addition, length of hospital stay and surgi-cal complications were similar to a group of 134 patients, previ-ously reported by one of the authors (P.L), undergoing thyroid

surgery using general anesthesia in an outpatient and short-staysetting (11). These patients had an average length of hospitalstay of 0.49 days and surgical complications including 6% tran-sient hypocalcemia and 0.75% permanent recurrent laryngealnerve injury. There were no cases of permanent hypoparathy-roidism, temporary hoarseness, wound infection, or hematoma.It is essential to screen patients for factors that might extend

intraoperative time leading to complications such as conversionto general anesthesia. These factors can include type or extent ofsurgery, patient age or body habitus, underlying medical prob-lems, and patientmotivation. By eschewing situations that couldprolong the procedure, the complications resulting from localanesthesia might be minimized.

Our study is the largest United States series describing patientcharacteristics, techniques, and perioperative course of patientsundergoing thyroid surgery using local anesthesia. In a selectgroup of patients, local anesthesia provides a simple and safe al-ternative to general anesthesia. The two most important predic-tors of success for thyroid surgery under local anesthesia is awell-informed patient and a surgeon who is skilled at adminis-tering local anesthesia. Even obstacles such as obesity, and un-

derlying medical problems including deafness can be overcomeif the patient is cooperative. By carefully screening patients pre-operatively and competently performing a cervical block, localanesthesia for thyroid surgery can be employed successfully in a

broad range of patients.

REFERENCES

1. Lo Gerfo P, Gates R, Gazetas P 1991 Outpatient and short-stay thyroidsurgery. Head Neck Surg 13:97-101.

2. Cunningham IG 1975 The management of solitary thyroid nodules un-der local anesthesia. Aust NZ J Surg 45:285-289.

3. Pastukhov NA, Shestopalova AM 1975 Local anesthesia in conjunctionwith neuroleptanalgesia during surgery in thyrotoxicosis. Eksp KhirAnesteziol 3:77-80.

4. Vaneveskii VL, Kaiumova IK 1972 Anesthesiologic provisions forsurgery of the thyroid. Vest Khir 108:86-89.

5. Saxe AW, Brown E, Hamburgerer SW 1988 Thyroid and parathyroidsurgery performed with patient under regional anesthesia. Surgery103:415^120.

6. Hochman M, Fee W 1991 Thyroidectomy under local anesthesia. ArchOtolaryngol Head Neck Surg 117:405^107.

7. Prithvi Raj P, Pai U, Rawal N 1991 Techniques of regional anesthesia inadults. In: Prithvi Raj P (ed) Clinical Practice of Regional Anesthesia.Churchill Livingstone, New York, pp 276-281.

8. Murphy T 1988 Somatic blockade of the head and neck. In: Cousins M,Bridenbaugh P (eds) Neural Blockade in Clinical Anesthesia andManagement of Pain, 2nd ed. J.B. Lippincott Company, Philadelphia,pp 538-540.

9. Presbyterian Hospital Diet Manual 1988 Presbyterian Hospital in theCity ofNew York, New York, p 25.

10. Marshall M 1991 Preoperative evaluation of the patient. In: Prithvi RajP (ed) Clinical Practice ofRegional Anesthesia. Churchill Livingstone,New York, p 14.

11. Lo Gerfo P, Gates R, Gazetas P 1991 Outpatient and short-stay thyroidsurgery. Head Neck March/April:97-101.

Address reprint requests to:Paul Lo Gerfo, M.D.

Columbia-Presbyterian Medical Center622 West 168 Street, PH 14-125

New York, NY 10032