Trial Outcomes & Findings for Superficial, Cervical Block in Thyroid Surgery, a Randomized Controlled Trial (NCT NCT00472446)

NCT ID: NCT00472446

Last Updated: 2016-09-15

Results Overview

Patient administered Instrument to indicate pain on a level from 0 to 10. (0: no pain, 10: worst imaginable pain)

• Recruitment status: COMPLETED
• Study phase: PHASE2/PHASE3
• Target enrollment: 183 participants
• Primary outcome timeframe: 6 hours after surgery
• Results posted on: 2016-09-15

Participant Flow

Participant milestones

Measure	Cervivcal Block Before Surgery bilateral superficial cervical block placed before surgery (just before skin incision) bilateral superficial cervical block: 10 ml of 5% bupivacaine (Carbostesin®) was used for each side. Along the cranial dorsal edge of the sternocleidomastoid muscle, three deposits of approximately 2.5 ml were injected to anaesthetize the cervical plexus with its nervus transversus colli. To anaesthetize the region of the planned skin incision, the remaining 2·5 ml was injected subcutaneously on each side.	Cervivcal Block After Surgery bilateral superficial cervical block placed after surgery (just after skin closure) bilateral superficial cervical block: 10 ml of 5% bupivacaine (Carbostesin®) was used for each side. Along the cranial dorsal edge of the sternocleidomastoid muscle, three deposits of approximately 2.5 ml were injected to anaesthetize the cervical plexus with its nervus transversus colli. To anaesthetize the region of the planned skin incision, the remaining 2·5 ml was injected subcutaneously on each side.	Placebo Cervivcal Block Before Surgery placebo bilateral superficial cervical block placed before surgery (just before skin incision) placebo bilateral superficial cervical block: 10 ml of saline (the carrier of bupivacaine in the experimental treatment) was used for each side. Along the cranial dorsal edge of the sternocleidomastoid muscle, three deposits of approximately 2.5 ml were injected to anaesthetize the cervical plexus with its nervus transversus colli. To anaesthetize the region of the planned skin incision, the remaining 2·5 ml was injected subcutaneously on each side.	Placebo Cervivcal Block After Surgery placebo bilateral superficial cervical block with saline placed after surgery (just after skin closure) placebo bilateral superficial cervical block: 10 ml of saline (the carrier of bupivacaine in the experimental treatment) was used for each side. Along the cranial dorsal edge of the sternocleidomastoid muscle, three deposits of approximately 2.5 ml were injected to anaesthetize the cervical plexus with its nervus transversus colli. To anaesthetize the region of the planned skin incision, the remaining 2·5 ml was injected subcutaneously on each side.
Overall Study STARTED	46	47	45	45
Overall Study COMPLETED	41	41	38	39
Overall Study NOT COMPLETED	5	6	7	6

Reasons for withdrawal

Measure	Cervivcal Block Before Surgery bilateral superficial cervical block placed before surgery (just before skin incision) bilateral superficial cervical block: 10 ml of 5% bupivacaine (Carbostesin®) was used for each side. Along the cranial dorsal edge of the sternocleidomastoid muscle, three deposits of approximately 2.5 ml were injected to anaesthetize the cervical plexus with its nervus transversus colli. To anaesthetize the region of the planned skin incision, the remaining 2·5 ml was injected subcutaneously on each side.	Cervivcal Block After Surgery bilateral superficial cervical block placed after surgery (just after skin closure) bilateral superficial cervical block: 10 ml of 5% bupivacaine (Carbostesin®) was used for each side. Along the cranial dorsal edge of the sternocleidomastoid muscle, three deposits of approximately 2.5 ml were injected to anaesthetize the cervical plexus with its nervus transversus colli. To anaesthetize the region of the planned skin incision, the remaining 2·5 ml was injected subcutaneously on each side.	Placebo Cervivcal Block Before Surgery placebo bilateral superficial cervical block placed before surgery (just before skin incision) placebo bilateral superficial cervical block: 10 ml of saline (the carrier of bupivacaine in the experimental treatment) was used for each side. Along the cranial dorsal edge of the sternocleidomastoid muscle, three deposits of approximately 2.5 ml were injected to anaesthetize the cervical plexus with its nervus transversus colli. To anaesthetize the region of the planned skin incision, the remaining 2·5 ml was injected subcutaneously on each side.	Placebo Cervivcal Block After Surgery placebo bilateral superficial cervical block with saline placed after surgery (just after skin closure) placebo bilateral superficial cervical block: 10 ml of saline (the carrier of bupivacaine in the experimental treatment) was used for each side. Along the cranial dorsal edge of the sternocleidomastoid muscle, three deposits of approximately 2.5 ml were injected to anaesthetize the cervical plexus with its nervus transversus colli. To anaesthetize the region of the planned skin incision, the remaining 2·5 ml was injected subcutaneously on each side.
Overall Study Protocol Violation	0	0	0	1
Overall Study Reintervention	0	0	1	1
Overall Study Questionnaires not returned	5	6	6	4

Baseline Characteristics

Superficial, Cervical Block in Thyroid Surgery, a Randomized Controlled Trial

Baseline characteristics by cohort

Measure	Cervivcal Block Before Surgery n=41 Participants bilateral superficial cervical block placed before surgery (just before skin incision) bilateral superficial cervical block: 10 ml of 5% bupivacaine (Carbostesin®) was used for each side. Along the cranial dorsal edge of the sternocleidomastoid muscle, three deposits of approximately 2.5 ml were injected to anaesthetize the cervical plexus with its nervus transversus colli. To anaesthetize the region of the planned skin incision, the remaining 2·5 ml was injected subcutaneously on each side.	Cervivcal Block After Surgery n=41 Participants bilateral superficial cervical block placed after surgery (just after skin closure) bilateral superficial cervical block: 10 ml of 5% bupivacaine (Carbostesin®) was used for each side. Along the cranial dorsal edge of the sternocleidomastoid muscle, three deposits of approximately 2.5 ml were injected to anaesthetize the cervical plexus with its nervus transversus colli. To anaesthetize the region of the planned skin incision, the remaining 2·5 ml was injected subcutaneously on each side.	Placebo Cervivcal Block Before Surgery n=38 Participants placebo bilateral superficial cervical block placed before surgery (just before skin incision) placebo bilateral superficial cervical block: 10 ml of saline (the carrier of bupivacaine in the experimental treatment) was used for each side. Along the cranial dorsal edge of the sternocleidomastoid muscle, three deposits of approximately 2.5 ml were injected to anaesthetize the cervical plexus with its nervus transversus colli. To anaesthetize the region of the planned skin incision, the remaining 2·5 ml was injected subcutaneously on each side.	Placebo Cervivcal Block After Surgery n=39 Participants placebo bilateral superficial cervical block with saline placed after surgery (just after skin closure) placebo bilateral superficial cervical block: 10 ml of saline (the carrier of bupivacaine in the experimental treatment) was used for each side. Along the cranial dorsal edge of the sternocleidomastoid muscle, three deposits of approximately 2.5 ml were injected to anaesthetize the cervical plexus with its nervus transversus colli. To anaesthetize the region of the planned skin incision, the remaining 2·5 ml was injected subcutaneously on each side.	Total n=159 Participants Total of all reporting groups
Age, Continuous	49.1 years STANDARD_DEVIATION 14.0 • n=5 Participants	46.5 years STANDARD_DEVIATION 13.3 • n=7 Participants	49.9 years STANDARD_DEVIATION 13.5 • n=5 Participants	47.3 years STANDARD_DEVIATION 14.4 • n=4 Participants	48.2 years STANDARD_DEVIATION 13.7 • n=21 Participants
Sex: Female, Male Female	33 Participants n=5 Participants	36 Participants n=7 Participants	29 Participants n=5 Participants	31 Participants n=4 Participants	129 Participants n=21 Participants
Sex: Female, Male Male	8 Participants n=5 Participants	5 Participants n=7 Participants	9 Participants n=5 Participants	8 Participants n=4 Participants	30 Participants n=21 Participants
Region of Enrollment Switzerland	41 participants n=5 Participants	41 participants n=7 Participants	38 participants n=5 Participants	39 participants n=4 Participants	159 participants n=21 Participants
resection location unilateral	18 participants n=5 Participants	22 participants n=7 Participants	24 participants n=5 Participants	26 participants n=4 Participants	90 participants n=21 Participants
resection location bilateral	23 participants n=5 Participants	19 participants n=7 Participants	14 participants n=5 Participants	13 participants n=4 Participants	69 participants n=21 Participants
duration of surgery	140.8 minutes STANDARD_DEVIATION 48.1 • n=5 Participants	130.5 minutes STANDARD_DEVIATION 37.0 • n=7 Participants	129.6 minutes STANDARD_DEVIATION 48.1 • n=5 Participants	141.9 minutes STANDARD_DEVIATION 50.4 • n=4 Participants	135.7 minutes STANDARD_DEVIATION 45.7 • n=21 Participants
specimen weight	60.4 gram STANDARD_DEVIATION 55.1 • n=5 Participants	42.2 gram STANDARD_DEVIATION 32.0 • n=7 Participants	51.0 gram STANDARD_DEVIATION 43.6 • n=5 Participants	39.8 gram STANDARD_DEVIATION 41.2 • n=4 Participants	47.0 gram STANDARD_DEVIATION 43.4 • n=21 Participants

PRIMARY outcome

Timeframe: 6 hours after surgery

Patient administered Instrument to indicate pain on a level from 0 to 10. (0: no pain, 10: worst imaginable pain)

Outcome measures

Measure	Cervivcal Block Before Surgery n=41 Participants bilateral superficial cervical block placed before surgery (just before skin incision) bilateral superficial cervical block: 10 ml of 5% bupivacaine (Carbostesin®) was used for each side. Along the cranial dorsal edge of the sternocleidomastoid muscle, three deposits of approximately 2.5 ml were injected to anaesthetize the cervical plexus with its nervus transversus colli. To anaesthetize the region of the planned skin incision, the remaining 2·5 ml was injected subcutaneously on each side.	Cervivcal Block After Surgery n=41 Participants bilateral superficial cervical block placed after surgery (just after skin closure) bilateral superficial cervical block: 10 ml of 5% bupivacaine (Carbostesin®) was used for each side. Along the cranial dorsal edge of the sternocleidomastoid muscle, three deposits of approximately 2.5 ml were injected to anaesthetize the cervical plexus with its nervus transversus colli. To anaesthetize the region of the planned skin incision, the remaining 2·5 ml was injected subcutaneously on each side.	Placebo Cervivcal Block Before Surgery n=38 Participants placebo bilateral superficial cervical block placed before surgery (just before skin incision) placebo bilateral superficial cervical block: 10 ml of saline (the carrier of bupivacaine in the experimental treatment) was used for each side. Along the cranial dorsal edge of the sternocleidomastoid muscle, three deposits of approximately 2.5 ml were injected to anaesthetize the cervical plexus with its nervus transversus colli. To anaesthetize the region of the planned skin incision, the remaining 2·5 ml was injected subcutaneously on each side.	Placebo Cervivcal Block After Surgery n=39 Participants placebo bilateral superficial cervical block with saline placed after surgery (just after skin closure) placebo bilateral superficial cervical block: 10 ml of saline (the carrier of bupivacaine in the experimental treatment) was used for each side. Along the cranial dorsal edge of the sternocleidomastoid muscle, three deposits of approximately 2.5 ml were injected to anaesthetize the cervical plexus with its nervus transversus colli. To anaesthetize the region of the planned skin incision, the remaining 2·5 ml was injected subcutaneously on each side.
Post-operative Pain Measured by Visual Analogue Scale	2.15 units on a scale Standard Deviation 2.17	2.02 units on a scale Standard Deviation 2.06	2.84 units on a scale Standard Deviation 1.75	2.72 units on a scale Standard Deviation 1.89

PRIMARY outcome

Timeframe: 4 days after surgery

Pain was obtained using the visual analog scale (VAS) three times daily for the 4 postoperative days (0 = no pain, 10 = worst imaginable pain)

The pooled relative treatment effect is the probability of values being higher in one group than in another group (ranging from 0 to 1)

Outcome measures

Measure	Cervivcal Block Before Surgery n=41 Participants bilateral superficial cervical block placed before surgery (just before skin incision) bilateral superficial cervical block: 10 ml of 5% bupivacaine (Carbostesin®) was used for each side. Along the cranial dorsal edge of the sternocleidomastoid muscle, three deposits of approximately 2.5 ml were injected to anaesthetize the cervical plexus with its nervus transversus colli. To anaesthetize the region of the planned skin incision, the remaining 2·5 ml was injected subcutaneously on each side.	Cervivcal Block After Surgery n=41 Participants bilateral superficial cervical block placed after surgery (just after skin closure) bilateral superficial cervical block: 10 ml of 5% bupivacaine (Carbostesin®) was used for each side. Along the cranial dorsal edge of the sternocleidomastoid muscle, three deposits of approximately 2.5 ml were injected to anaesthetize the cervical plexus with its nervus transversus colli. To anaesthetize the region of the planned skin incision, the remaining 2·5 ml was injected subcutaneously on each side.	Placebo Cervivcal Block Before Surgery n=38 Participants placebo bilateral superficial cervical block placed before surgery (just before skin incision) placebo bilateral superficial cervical block: 10 ml of saline (the carrier of bupivacaine in the experimental treatment) was used for each side. Along the cranial dorsal edge of the sternocleidomastoid muscle, three deposits of approximately 2.5 ml were injected to anaesthetize the cervical plexus with its nervus transversus colli. To anaesthetize the region of the planned skin incision, the remaining 2·5 ml was injected subcutaneously on each side.	Placebo Cervivcal Block After Surgery n=39 Participants placebo bilateral superficial cervical block with saline placed after surgery (just after skin closure) placebo bilateral superficial cervical block: 10 ml of saline (the carrier of bupivacaine in the experimental treatment) was used for each side. Along the cranial dorsal edge of the sternocleidomastoid muscle, three deposits of approximately 2.5 ml were injected to anaesthetize the cervical plexus with its nervus transversus colli. To anaesthetize the region of the planned skin incision, the remaining 2·5 ml was injected subcutaneously on each side.
Pooled Relative Treatment Effect of VAS	0.47 pooled relative treatment effect Interval 0.43 to 0.51	0.45 pooled relative treatment effect Interval 0.41 to 0.48	0.55 pooled relative treatment effect Interval 0.51 to 0.59	0.54 pooled relative treatment effect Interval 0.51 to 0.58

SECONDARY outcome

Timeframe: 24 hours after surgery

Patient administered Instrument to indicate pain on a level from 0 to 10. (0: no pain, 10: worst imaginable pain)

Outcome measures

Measure	Cervivcal Block Before Surgery n=41 Participants bilateral superficial cervical block placed before surgery (just before skin incision) bilateral superficial cervical block: 10 ml of 5% bupivacaine (Carbostesin®) was used for each side. Along the cranial dorsal edge of the sternocleidomastoid muscle, three deposits of approximately 2.5 ml were injected to anaesthetize the cervical plexus with its nervus transversus colli. To anaesthetize the region of the planned skin incision, the remaining 2·5 ml was injected subcutaneously on each side.	Cervivcal Block After Surgery n=41 Participants bilateral superficial cervical block placed after surgery (just after skin closure) bilateral superficial cervical block: 10 ml of 5% bupivacaine (Carbostesin®) was used for each side. Along the cranial dorsal edge of the sternocleidomastoid muscle, three deposits of approximately 2.5 ml were injected to anaesthetize the cervical plexus with its nervus transversus colli. To anaesthetize the region of the planned skin incision, the remaining 2·5 ml was injected subcutaneously on each side.	Placebo Cervivcal Block Before Surgery n=38 Participants placebo bilateral superficial cervical block placed before surgery (just before skin incision) placebo bilateral superficial cervical block: 10 ml of saline (the carrier of bupivacaine in the experimental treatment) was used for each side. Along the cranial dorsal edge of the sternocleidomastoid muscle, three deposits of approximately 2.5 ml were injected to anaesthetize the cervical plexus with its nervus transversus colli. To anaesthetize the region of the planned skin incision, the remaining 2·5 ml was injected subcutaneously on each side.	Placebo Cervivcal Block After Surgery n=39 Participants placebo bilateral superficial cervical block with saline placed after surgery (just after skin closure) placebo bilateral superficial cervical block: 10 ml of saline (the carrier of bupivacaine in the experimental treatment) was used for each side. Along the cranial dorsal edge of the sternocleidomastoid muscle, three deposits of approximately 2.5 ml were injected to anaesthetize the cervical plexus with its nervus transversus colli. To anaesthetize the region of the planned skin incision, the remaining 2·5 ml was injected subcutaneously on each side.
Post-operative Pain Measured by Visual Analogue Scale	1.95 units on a scale Standard Deviation 1.55	1.51 units on a scale Standard Deviation 1.48	2.20 units on a scale Standard Deviation 1.66	2.06 units on a scale Standard Deviation 1.39

SECONDARY outcome

Timeframe: 5 days after surgery

number of participants taking post-operative analgetics

Outcome measures

Measure	Cervivcal Block Before Surgery n=41 Participants bilateral superficial cervical block placed before surgery (just before skin incision) bilateral superficial cervical block: 10 ml of 5% bupivacaine (Carbostesin®) was used for each side. Along the cranial dorsal edge of the sternocleidomastoid muscle, three deposits of approximately 2.5 ml were injected to anaesthetize the cervical plexus with its nervus transversus colli. To anaesthetize the region of the planned skin incision, the remaining 2·5 ml was injected subcutaneously on each side.	Cervivcal Block After Surgery n=41 Participants bilateral superficial cervical block placed after surgery (just after skin closure) bilateral superficial cervical block: 10 ml of 5% bupivacaine (Carbostesin®) was used for each side. Along the cranial dorsal edge of the sternocleidomastoid muscle, three deposits of approximately 2.5 ml were injected to anaesthetize the cervical plexus with its nervus transversus colli. To anaesthetize the region of the planned skin incision, the remaining 2·5 ml was injected subcutaneously on each side.	Placebo Cervivcal Block Before Surgery n=38 Participants placebo bilateral superficial cervical block placed before surgery (just before skin incision) placebo bilateral superficial cervical block: 10 ml of saline (the carrier of bupivacaine in the experimental treatment) was used for each side. Along the cranial dorsal edge of the sternocleidomastoid muscle, three deposits of approximately 2.5 ml were injected to anaesthetize the cervical plexus with its nervus transversus colli. To anaesthetize the region of the planned skin incision, the remaining 2·5 ml was injected subcutaneously on each side.	Placebo Cervivcal Block After Surgery n=39 Participants placebo bilateral superficial cervical block with saline placed after surgery (just after skin closure) placebo bilateral superficial cervical block: 10 ml of saline (the carrier of bupivacaine in the experimental treatment) was used for each side. Along the cranial dorsal edge of the sternocleidomastoid muscle, three deposits of approximately 2.5 ml were injected to anaesthetize the cervical plexus with its nervus transversus colli. To anaesthetize the region of the planned skin incision, the remaining 2·5 ml was injected subcutaneously on each side.
Consumption of Post-operative Analgetics paracetamol	21 participants	23 participants	18 participants	24 participants
Consumption of Post-operative Analgetics metamizole	6 participants	7 participants	3 participants	7 participants

SECONDARY outcome

Timeframe: 5 days after surgery

mean pooled dose of post-operative analgetics

Outcome measures

Measure	Cervivcal Block Before Surgery n=41 Participants bilateral superficial cervical block placed before surgery (just before skin incision) bilateral superficial cervical block: 10 ml of 5% bupivacaine (Carbostesin®) was used for each side. Along the cranial dorsal edge of the sternocleidomastoid muscle, three deposits of approximately 2.5 ml were injected to anaesthetize the cervical plexus with its nervus transversus colli. To anaesthetize the region of the planned skin incision, the remaining 2·5 ml was injected subcutaneously on each side.	Cervivcal Block After Surgery n=41 Participants bilateral superficial cervical block placed after surgery (just after skin closure) bilateral superficial cervical block: 10 ml of 5% bupivacaine (Carbostesin®) was used for each side. Along the cranial dorsal edge of the sternocleidomastoid muscle, three deposits of approximately 2.5 ml were injected to anaesthetize the cervical plexus with its nervus transversus colli. To anaesthetize the region of the planned skin incision, the remaining 2·5 ml was injected subcutaneously on each side.	Placebo Cervivcal Block Before Surgery n=38 Participants placebo bilateral superficial cervical block placed before surgery (just before skin incision) placebo bilateral superficial cervical block: 10 ml of saline (the carrier of bupivacaine in the experimental treatment) was used for each side. Along the cranial dorsal edge of the sternocleidomastoid muscle, three deposits of approximately 2.5 ml were injected to anaesthetize the cervical plexus with its nervus transversus colli. To anaesthetize the region of the planned skin incision, the remaining 2·5 ml was injected subcutaneously on each side.	Placebo Cervivcal Block After Surgery n=39 Participants placebo bilateral superficial cervical block with saline placed after surgery (just after skin closure) placebo bilateral superficial cervical block: 10 ml of saline (the carrier of bupivacaine in the experimental treatment) was used for each side. Along the cranial dorsal edge of the sternocleidomastoid muscle, three deposits of approximately 2.5 ml were injected to anaesthetize the cervical plexus with its nervus transversus colli. To anaesthetize the region of the planned skin incision, the remaining 2·5 ml was injected subcutaneously on each side.
Mean Consumption of Post-operative Analgetics paracetamol	3.33 gram Standard Deviation 2.43	3.37 gram Standard Deviation 2.43	4.06 gram Standard Deviation 3.19	4.33 gram Standard Deviation 3.56
Mean Consumption of Post-operative Analgetics metamizole	1.25 gram Standard Deviation 0.88	.93 gram Standard Deviation 0.61	2.46 gram Standard Deviation 2.53	1.21 gram Standard Deviation 0.64

SECONDARY outcome

Timeframe: 90 days

time from surgery to Hospital release in days

Outcome measures

Measure	Cervivcal Block Before Surgery n=41 Participants bilateral superficial cervical block placed before surgery (just before skin incision) bilateral superficial cervical block: 10 ml of 5% bupivacaine (Carbostesin®) was used for each side. Along the cranial dorsal edge of the sternocleidomastoid muscle, three deposits of approximately 2.5 ml were injected to anaesthetize the cervical plexus with its nervus transversus colli. To anaesthetize the region of the planned skin incision, the remaining 2·5 ml was injected subcutaneously on each side.	Cervivcal Block After Surgery n=41 Participants bilateral superficial cervical block placed after surgery (just after skin closure) bilateral superficial cervical block: 10 ml of 5% bupivacaine (Carbostesin®) was used for each side. Along the cranial dorsal edge of the sternocleidomastoid muscle, three deposits of approximately 2.5 ml were injected to anaesthetize the cervical plexus with its nervus transversus colli. To anaesthetize the region of the planned skin incision, the remaining 2·5 ml was injected subcutaneously on each side.	Placebo Cervivcal Block Before Surgery n=38 Participants placebo bilateral superficial cervical block placed before surgery (just before skin incision) placebo bilateral superficial cervical block: 10 ml of saline (the carrier of bupivacaine in the experimental treatment) was used for each side. Along the cranial dorsal edge of the sternocleidomastoid muscle, three deposits of approximately 2.5 ml were injected to anaesthetize the cervical plexus with its nervus transversus colli. To anaesthetize the region of the planned skin incision, the remaining 2·5 ml was injected subcutaneously on each side.	Placebo Cervivcal Block After Surgery n=39 Participants placebo bilateral superficial cervical block with saline placed after surgery (just after skin closure) placebo bilateral superficial cervical block: 10 ml of saline (the carrier of bupivacaine in the experimental treatment) was used for each side. Along the cranial dorsal edge of the sternocleidomastoid muscle, three deposits of approximately 2.5 ml were injected to anaesthetize the cervical plexus with its nervus transversus colli. To anaesthetize the region of the planned skin incision, the remaining 2·5 ml was injected subcutaneously on each side.
Hospital Stay	1.8 days Standard Deviation 0.7	1.6 days Standard Deviation 0.7	2.0 days Standard Deviation 1.1	1.6 days Standard Deviation 0.6

Adverse Events

Cervivcal Block Before Surgery

Serious events: 0 serious events

Other events: 0 other events

Deaths: 0 deaths

Cervivcal Block After Surgery

Serious events: 0 serious events

Other events: 0 other events

Deaths: 0 deaths

Placebo Cervivcal Block Before Surgery

Serious events: 0 serious events

Other events: 0 other events

Deaths: 0 deaths

Placebo Cervivcal Block After Surgery

Serious events: 1 serious events

Other events: 0 other events

Deaths: 0 deaths

Serious adverse events

Measure	Cervivcal Block Before Surgery n=41 participants at risk bilateral superficial cervical block placed before surgery (just before skin incision) bilateral superficial cervical block: 10 ml of 5% bupivacaine (Carbostesin®) was used for each side. Along the cranial dorsal edge of the sternocleidomastoid muscle, three deposits of approximately 2.5 ml were injected to anaesthetize the cervical plexus with its nervus transversus colli. To anaesthetize the region of the planned skin incision, the remaining 2·5 ml was injected subcutaneously on each side.	Cervivcal Block After Surgery n=41 participants at risk bilateral superficial cervical block placed after surgery (just after skin closure) bilateral superficial cervical block: 10 ml of 5% bupivacaine (Carbostesin®) was used for each side. Along the cranial dorsal edge of the sternocleidomastoid muscle, three deposits of approximately 2.5 ml were injected to anaesthetize the cervical plexus with its nervus transversus colli. To anaesthetize the region of the planned skin incision, the remaining 2·5 ml was injected subcutaneously on each side.	Placebo Cervivcal Block Before Surgery n=38 participants at risk placebo bilateral superficial cervical block placed before surgery (just before skin incision) placebo bilateral superficial cervical block: 10 ml of saline (the carrier of bupivacaine in the experimental treatment) was used for each side. Along the cranial dorsal edge of the sternocleidomastoid muscle, three deposits of approximately 2.5 ml were injected to anaesthetize the cervical plexus with its nervus transversus colli. To anaesthetize the region of the planned skin incision, the remaining 2·5 ml was injected subcutaneously on each side.	Placebo Cervivcal Block After Surgery n=39 participants at risk placebo bilateral superficial cervical block with saline placed after surgery (just after skin closure) placebo bilateral superficial cervical block: 10 ml of saline (the carrier of bupivacaine in the experimental treatment) was used for each side. Along the cranial dorsal edge of the sternocleidomastoid muscle, three deposits of approximately 2.5 ml were injected to anaesthetize the cervical plexus with its nervus transversus colli. To anaesthetize the region of the planned skin incision, the remaining 2·5 ml was injected subcutaneously on each side.
Blood and lymphatic system disorders hemorrhage	0.00% 0/41 • 6 weeks after surgery	0.00% 0/41 • 6 weeks after surgery	0.00% 0/38 • 6 weeks after surgery	2.6% 1/39 • Number of events 1 • 6 weeks after surgery

Other adverse events

Adverse event data not reported

Additional Information

Thomas Steffen, MD

Cantonal Hospital St. Gallen

Phone: 0041 71 494 1111

Email: thomas.steffen@kssg.ch

Results disclosure agreements

• Principal investigator is a sponsor employee
• Publication restrictions are in place