Ultrasound-guided interscalene block versus intravenous analgesia and sedation for reduction of first anterior shoulder dislocation

a b s t r a c t

Purpose: This study aims to compare the efficacy of ultrasound-guided interscalene block (US-ISB) with that of intravenous analgesia and sedation (IVAS) in reducing first Shoulder dislocation.

Material and methods: A prospective study was performed in 66 patients with first Anterior shoulder dislocation in emergency department. The patients were divided into a US-ISB (n = 32) group and an IVAS (IVAS n = 34) group. The procedure time (anesthesia, reduction, and hospital times), pain score (before, during, and after re- duction), Reduction attempts, complications, and patient satisfaction were recorded and compared between the two groups.

Results: The anesthesia time (P < 0.01) and Reduction time (P < 0.01) were shorter and the hospital time (P < 0.01) was longer in the IVAS group than in the US-ISB group. No significant differences in preoperative (P = 0.18) and postoperative (P = 0.27) pain scores were found between the two groups, but the intraoperative score of the US-ISB group was significantly higher than that of the IVAS group. More reduction attempts (P < 0.01) were recorded in the US-ISB group than that in the IVAS group. Complications (P < 0.01) such as nausea, vomiting, headache, and hypoxia occurred more frequently in the IVAS group than in the US-ISB group. No sig- nificant difference in patient satisfaction was observed between two groups (P = 0.96).

Conclusion: Compared with IVAS group, US-ISB group reduces the Time to discharge and achieves lesser compli- cation. The pain score and reduction attempt are lower in the IVAS group than in the US-ISB group.

(C) 2022 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY-NC-ND license (http://

  1. Introduction

With an estimated incidence of 1.1 per 1000, Traumatic dislocation of the shoulder is more common than that of other joints in emergency de- partments [1]. Many techniques to reduce traumatic shoulder disloca- tion have been described [2]. However, adequate sedation and Muscle relaxation are required because of the pain and anxiety associated with the reduction process [3]. Intravenous analgesia and sedation (IVAS) is widely preferred in manual closed reduction of shoulder dislo- cation in many medical institutions [3-5].

Interscalene block (ISB) is a regional anesthetic technique com- monly employed for shoulder surgery for many years. It is preferred by surgeons because of its full intraoperative anesthetic effect and satis- factory postoperative analgesic effect [6]. However, a long time is needed before the anesthesia takes effect. The effect of anesthesia also varies per person. Recently, the application of ultrasound-guided interscalene block (US-ISB) in Shoulder joint surgery has become

* Corresponding author at: Department of Orthopaedic Surgery, The Affiliated Hospital of Medical School of Ningbo University, Ningbo, Zhejiang, China.

E-mail address: [email protected] (H. Mao).

gradually accepted [6,7]. Ultrasound can clearly identify the nerve and its surrounding tissue, improving the accuracy of target nerve injection [8]. Compared with the neurostimulator-guided approach, US-ISB might achieve higher success rate and decrease the incidence of pares- thesia and Local anesthetic toxicity [9,10].

This study aims to compare the safety and efficacy of US-ISB with those of IVAS in reducing first shoulder dislocation. The hypothesis of this study is that the US-ISB and IVAS groups show no difference in out- come parameters.

  1. Materials and methods

A prospective study was performed in patients with anterior shoul- der dislocation in our traumatic center from 2019 to 2021. The efficacy of US-ISB was compared with that of IVAS in reducing first shoulder dis- location among patients older than 18 years. This study was approved by the Ethics Committee of our institute, and written informed consent obtained from each patient.

Inclusion criteria: Adult patients (older than 18 years) who were di- agnosed for the first time with shoulder dislocation on the basis of clin- ical symptoms and radiographic examination. Exclusion criteria:

0735-6757/(C) 2022 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY-NC-ND license (

habitual dislocation, patients accompanied with proximal humeral frac- ture, Bilateral shoulder dislocation, and patients who refused to partici- pate in this study. Patients were randomly divided into US-ISB and IVAS groups.

The patients were guided into the operating room, where Peripheral venous access was routinely opened and oxygen was inhaled by mask. The physical signs, including blood pressure, heart rate, and electrocar- diogram, of the patients were monitored in real time. In the US-ISB group, a high-frequency ultrasound transducer (DC-7 Mindray ultra- sound machine, China) was used to locate the injection site where was the level of roots to trunks. With the trachea, carotid artery, and jugular vein as markers, the high-frequency probe was gradually moved outward or up and down in the patient’s neck. Two or three darker ring images were detected between the anterior scalenus and the second scalenus. Approximately 20 mL of 0.5% ropivacaine was injected around the brachial plexus. In the IVAS group, the patients were anesthetized with intravenous propofol combined with a small dose of fentanyl. The sequence was to inject fentanyl 1 first within 1 min and then inject propofol 2 Manual reduction of shoulder Joint dislocation was performed after the patient lost consciousness.

    1. Outcomes

Procedure time included anesthesia, reduction, and hospital times. Anesthesia time was the period between the onset of anesthesia and the preparation for surgical reduction. Reduction time was the period from the beginning to the reduction. Hospital time was the period when the patient stayed in the hospital. The number of reduction at- tempts was also recorded, including the number of reduction failures. Failure was defined as three times of unSuccessful reduction or severe complications.

Subjective pain intensity was measured in accordance with the nu- meric rating scale [11]. After the patient had fully recovered, the pain questionnaire, which included the pain scores before and after reduc- tion, was administered by a nurse.

The surgical complications recorded included nausea, vomiting, headache, hypoxia, and other anesthesia-related side effects.

Patient satisfaction was assessed using a 5-point scale (5 = completely satisfied, 4 = satisfied, 3 = neutral, 2 = dissatisfied, and 1= very dissatisfied).

    1. Statistical analysis

Data were analyzed using SPSS 19 software (SPSS Inc., Chicago, IL, USA). The mean and the median were used to describe quantitative var- iables with normal and non-normal distribution. For qualitative vari- ables, percent of frequency was used. Categorical data between the two groups were compared using ?2 with Yates’ correction or Fisher’s exact-test when a cell had an expected frequency of less than 5. Contin- uous data were compared by an independent two-sample t-test or anal- ysis of variance test. Statistical significance was considered at P < 0.05.

  1. Results

A total of 80 patients with shoulder dislocation were enrolled in this study. Eight patients were excluded, including six patients who refused to participate in the study, one who was younger than 18 years of age, and one who was diagnosed with posterior shoulder dislocation. Six pa- tients were lost contact during follow-up. In the end, 66 patients com- pleted the study, including 32 patients in the US-ISB group and 34 patients in the IVAS group (Fig. 1). No significant differences in gender, age, injury site, or trauma mechanism were found between the two groups (Table. 1). (See Table. 2).

No statistical difference in preoperative (P = 0.18) and postopera- tive pain (P = 0.27) scores was found between the two groups. How- ever, the pain was more obvious in the US-ISB group than in the IVAS group.

In the IVAS group, most patients (27/34) had a successful reduction in the first attempt, six patients were successful on the second attempt, and only one had the third attempt. In the US-ISB group, twenty patients were successful in their first reduction attempt, eight patients acquired

Total number of patents with shoulder dislocation



Refused to participate (n=6) Age<18 year (n=1)

Posterior dislocation (n=1)

Eligible patients (n=72)

IVAS group (n=36)

Lost to follow up (n=4)

Lost to follow up (n=2)

IVAS group (n=34)

US-ISB group (n=36)

US-ISB group (n=32)

Fig. 1. Flow diagram.

Table. 1

Demographic data of patients.

Patients and variables



P value

Number of patients




47.96 +- 14.14

48.83 +- 12.48










Operation site








Traumatic causes


Vehicle collision












reduction in the second attempt, and three patients needed the third at- tempt. However, one patient failed to obtain anatomical reduction. Ad- ditional general analgesia was adopted to perform shoulder reduction. Anesthesia time (P < 0.01) and reduction time (P < 0.01) were much longer in the US-ISB group than in the IVAS group. However, hospital time (P < 0.01) was much shorter in the US-ISB group than in the

IVAS group.

Nausea/vomiting, headache, and hypoxia were the most common complications after operation. Nausea/vomiting was documented in five patients in the IVAS group and in only one patient in the US-ISB group. Three had headaches and two had hypoxia in the IVAS group.

No significant difference in patient satisfaction was noted between the two groups (P = 0.96).

  1. Discussion

Shoulder dislocation is the most common dislocation in clinical prac- tice. Various techniques for shoulder reduction have been described in the literature [2]. Adequate muscle relaxation and pain control play an important role in rapid, effective, and safe reduction [12,13]. Tradition- ally, intravenous analgesia is a common choice in many emergency de- partments [14]. Meanwhile US-ISB is also a safe and effective technique to resolve anterior Shoulder dislocations. Ultrasound guidance for anes- thesia allows direct visualization of nerves, providing a sufficient block- ade and reducing additional local anesthetic infiltration [15]. Therefore, the present study aims to compare the two anesthesia methods in shoulder reduction.

Pain score before reduction was the baseline. No statistical differ- ence was observed in this baseline between the two groups. In the IVAS group, patients who lost consciousness were not scored for pain during the reduction. In the US-ISB group, although the intraoperative

Table. 2

Comparison of outcomes between two groups.

US-ISB(n = 32) IVAS(n = 34) P value

Pain score

Before reduction

8.29 +- 0.92

8.19 +- 0.89


During reduction

2.34 +- 1.34


After reduction

Reduction attempts

1.74 +- 0.74

1.97 +- 0.95









Three times






Anesthesia time(min)

16.41 +- 3.62

8.66 +- 2.29


Reduction time (min)

4.08 +- 1.55

2.16 +- 0.83


Hospital time (h)


6.12 +- 1.32

9.38 +- 1.96



Nausea/ vomiting









Patient satisfaction

4.49 +- 0.58

4.60 +- 0.53


pain was slightly more pronounced, it was alleviated after the operation. Pain scores after reduction might not truly reflect the effectiveness of analgesia because the pain disappears once the dislocated joint was re- duction [16]. Compared with IVAS, US-ISB required longer anesthesia time to ensure that the pain was relieved enough to allow the reduction; in addition, it might need multiple attempts and even cause a risk of fail- ure [17]. As the pain was alleviated, patients required minimal or no se- dation during the manipulation [7]. Compared with patients under US- ISB, patients under general anesthesia were much more likely to achieve a successful initial reduction. This finding was associated with rapid an- algesia and muscle relaxation. However, the disadvantages were also obvious. Postoperative nausea and vomiting, headache, and hypoxia symptoms were more common among patients under general anesthe- sia than among patients under US-ISB. Patients need more nursing and monitoring during the whole process, which increased the Medical cost

[18] and prolonged the hospital time. Therefore, patients were often re- quired to fast for about 4-6 h before surgery to reduce these postoper- ative complications [19]. However, this decision can lead patients waiting and suffering pain in the emergency room. The average hospital stay in IVAS group was 3 h longer than in US-ISB group. Prolonged mon- itoring and hospitalization thereby reduced the medical experience and satisfaction of patients [16]. Although this failed case was only rated 2 points, no significant difference in patient satisfaction scores was found between the two groups.

Therefore, in primary medical institutions or areas with insufficient medical resources, shoulder dislocation can be treated using US-ISB first, whereas IVAS can be used as a remedy for difficult cases.

    1. Limitation

The first limitation of this study was the small sample size, causing a high risk of deviation in the conclusion. In addition, the study did not ac- curately evaluate muscle relaxation level. Finally, all patients were treated at the same medical center, and a multi-center source of cases was lacking.

  1. Conclusion

Shoulder reduction can be accomplished using US-ISB or IVAS. US- IBS reduces the time to discharge from the emergency department and minimizes complications. The pain score and reduction attempt are lower in the IVAS group than in the US-IBS group.

Grant support

This research was funded Medical and health science and Technol- ogy project of Zhejiang Province (2022KY1146).

Author contributions

Study concept and design: haijiao mao.

Acquisition analysis, or interpretation of data: all authors. Statistical analysis: zeting Wu.

Drafting of the manuscript: liwei Yao. Critical revision of the manuscript for important intellectual content:

wenwei Dong, qingzhen Zhao, haijiao Mao.

Study supervision: haijiao Mao.

Credit authorship contribution statement

Liwei Yao: Writing – original draft, Formal analysis. Wenwei Dong: Supervision, Writing – review & editing. Zeting Wu: Formal analysis, Data curation. Qingzhen Zhao: Investigation, Project administration. Haijiao Mao: Writing – review & editing, Project administration, Conceptualization.

Declaration of competing interest

All authors have completed and submitted the ICMJE Form for Dis- closure of Potential Conflicts of Interest. The authors have no indepen- dent disclosures or conflicts of interest.


  1. Yang NP, Chen HC, Phan DV, et al. Epidemiological survey of orthopedic joint dislo- cations based on nationwide insurance data in Taiwan, 2000-2005. BMC Musculoskelet Disord. 2011;12:253.
  2. Gottlieb M. Shoulder dislocations in the emergency department: a comprehensive review of reduction techniques. J Emerg Med. 2020;58(4):647-66.
  3. Vahidi E, Hemati R, Momeni M, Jahanshir A, Saeedi M. Comparison of sedative effec- tiveness of thiopental versus midazolam in reduction of shoulder dislocation. World J Emerg Med. 2018;9(2):125-9.
  4. Burton JH, Bock AJ, Strout TD, Marcolini EG. Etomidate and midazolam for reduction of anterior shoulder dislocation: a randomized, controlled trial. Ann Emerg Med. 2002;40(5):496-504.
  5. Jiang N, Hu YJ, Zhang KR, Zhang S, Bin Y. Intra-articular lidocaine versus intravenous analgesia and sedation for manual closed reduction of acute anterior shoulder dislo- cation: an updated meta-analysis. J Clin Anesth. 2014;26(5):350-9.
  6. Karaman T, Karaman S, Asci M, et al. Comparison of ultrasound-guided supraclavic- ular and interscalene brachial plexus blocks in postoperative pain management after arthroscopic shoulder surgery. Pain Pract. 2019;19(2):196-203.
  7. Beh ZY, Osman A, Fathil S, Karmakar MK. ultrasound guided interscalene brachial plexus block with low dose sedation – technique of choice for reducing shoulder dis- location. Am J Emerg Med. 2018;36(4):717-8.
  8. Lim JA, Sung SY, Lee JH, et al. Comparison of ultrasound-guided and nerve stimulator-guided interscalene blocks as a sole anesthesia in shoulder arthroscopic rotator cuff repair: a retrospective study. Medicine (Baltimore). 2020;99(35): e21684.
  9. Spence BC, Beach ML, Gallagher JD, Sites BD. Ultrasound-guided interscalene blocks: understanding where to inject the local anaesthetic. Anaesthesia. 2011;66(6): 509-14.
  10. Marhofer P, Willschke H, Kettner S. Current concepts and future trends in ultrasound-guided regional anesthesia. Curr Opin Anaesthesiol. 2010;23(5):632-6.
  11. Jensen MP, Karoly P, Braver S. The measurement of clinical pain intensity: a compar- ison of six methods. Pain. 1986;27(1):117-26.
  12. Lachance PA. Reduction of shoulder dislocation: are communication and adequate relaxation more important than technique. Can Fam Physician. 2012;58(11): 1189-90. e613-4.
  13. Yuan W, Chua I. Should closed reduction be attempted in the emergency depart- ment for an acute anterior shoulder fracture dislocation. JSES Int. 2021;5(1):56-9.
  14. Kashani P, Asayesh Zarchi F, Hatamabadi HR, Afshar A, Amiri M. Intra-articular lido- caine versus intravenous sedative and analgesic for reduction of anterior shoulder dislocation. Turk J Emerg Med. 2016;16(2):60-4.
  15. Kim E, Choi CH, Kim JH. Effects of C8 nerve root block during interscalene brachial plexus block on anesthesia of the posterior shoulder in patients undergoing arthro- scopic shoulder surgery: study protocol for a prospective randomized parallel-group controlled trial. Trials. 2019;20(1):533.
  16. Cheok CY, Mohamad JA, Ahmad TS. Pain relief for reduction of acute anterior shoul- der dislocations: a prospective randomized study comparing intravenous sedation with intra-articular lidocaine. J Orthop Trauma. 2011;25(1):5-10.
  17. Furuhata R, Kamata Y, Matsumura N, Kono A, Morioka H. Risk factors for failure of reduction of anterior glenohumeral dislocation without sedation. J Shoulder Elbow Surg. 2021;30(2):306-11.
  18. Blaivas M, Adhikari S, Lander L. A prospective comparison of procedural sedation and ultrasound-guided interscalene nerve block for shoulder reduction in the emer- gency department. Acad Emerg Med. 2011;18(9):922-7.
  19. Green SM, Krauss B. Pulmonary aspiration risk during emergency department pro- cedural sedation-an examination of the role of fasting and sedation depth. Acad Emerg Med. 2002;9(1):35-42.