Prospective Observational Study on the Analgesic Effectiveness of Blocking the Shoulder´s Anterior Capsule and the Suprascapular Nerve by the Anterior Approach Versus Blocking of the Suprascapular and Axillary Nerves by the Posterior Approach in Shoulder Arthroscopy.
Conditions: Analgesia, Shoulder Arthropathy Associated With Other Conditions, Suprascapular and Axillary Nerve Block
Sponsor: Jose Manuel López González

• PROTOCOL TITLE 
 
Prospective observational study on the analgesic effectiveness of blocking the 
shoulder´s anterior capsule and the suprascapular nerve by the anterior approach 
versus blocking of the suprascapular and axillary nerves by the posterior approach in 
shoulder arthroscopy. 
 
• PROTOCOL CODE  
   SHAC 
 
• PROTOCOL VERSION WITH DATE  
   10/10/2023 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

ABSTRACT 
 
• PROTOCOL TITTLE 
Prospective observational study on the analgesic effectiveness of blocking the 
shoulder´s anterior capsule and the suprascapular nerve by the anterior approach 
versus blocking of the suprascapular and axillary nerves by the posterior approach in 
shoulder arthroscopy. 
 
• PROTOCOL CODE  
   SHAC 
 
•  STUDY DESIGN 
An observational study of paired cohorts, not randomized, is designed in two hospitals 
in northern Spain in the period between october 2023 and september 2024. 
 
• MAIN AND SECONDARY OBJECTIVES 
Main: 
The measurement of pain intensity according to the numerical rating scale (NRS) at 
different times: preoperative and at the 1st, 2nd, 12th and 24th postoperative hours. 
Secondary:  
Postoperative opioid consumption and comparison of total cumulative consumption 
between the two groups.  
It will also evaluated the degree of sensory and motor block, the easy of performance 
of the anesthetic technique,  the degree of patient satisfaction and the record of short-
term complications (first 24 hours post-intervention): hematoma, pruritus, nausea 
and/or vomiting. 
• Study population and total number of subjects. 
 
All patients consecutively scheduled for arthroscopic unilateral rotator cuff 
repair of the shoulder, who meet the inclusion criteria will be recruited for the study. 
 
 
 

 
BACKGROUND AND JUSTIFICATION OF THE PROJECT  
 
Arthroscopic shoulder surgery is related to a high incidence of postoperative pain, 
being rated as intense by 45% of patients in the immediate postoperative period (1).  
The management of these patients can be complex due to the high incidence of 
preoperative pain and its variability during the postoperative period, which is higher in 
patients undergoing rotator cuff repair surgery (2). 
It is crucial to ensure adequate postoperative pain control in this type of intervention, 
especially in the context of major outpatient surgery. Adequate postoperative pain 
control can have several benefits, such as reducing hospital stay (3), accelerating 
postoperative rehabilitation (4), and improving long-term outcomes (5).  
The PROSPECT guideline for rotator cuff repair surgery recommends associating a 
regional analgesic technique with a multimodal pharmacological approach to pain. (6). 
Traditionally, the interscalene block has been considered the gold-standard for 
analgesia in shoulder surgery; However, its possible serious complications limit its use. 
Currently, most anesthesiologists choose to perform more distal peripheral nerve 
blocks of the brachial plexus (upper trunk block, supraclavicular block, infraclavicular 
block at the costoclavicular level, axillary nerve block...) which, although highly 
effective, continue to cause impairment. prolonged motor activity and are not free of 
complications (phrenic paralysis, transient nerve injuries, inadvertent vascular 
punctures...) (7).  
Shoulder anterior capsular block (SHAC) has recently been described. It is a fascial 
block of the anterior capsule of the shoulder that aims to avoid motor impairment 
while maintaining optimal analgesic efficacy (8)(9). However, so far only anatomical 
and descriptive studies of small case series have been published. Therefore, this 
research work, with the objective of comparing the postoperative analgesic 
effectiveness of two regional analgesic techniques: the SHAC block associated with the 
suprascapular nerve block performed anteriorly vs. suprascapular and axillary nerve 
blocks performed posteriorly in operated patients. of the shoulder via arthroscopic 
procedures that cause intense postoperative pain. 
 

 
 
STUDY HYPOTHESES  
 
Two analgesic strategies included within the usual clinical practice will be compared 
for postoperative pain control after shoulder arthroscopy. With this study we want to 
compare the ultrasound-guided block of the suprascapular nerves and the shoulder 
joint capsule via the anterior route versus the ultrasound-guided block of the 
suprascapular and axillary nerves via the posterior route. 
 
GOALS:  
• Main objective 
 
The measurement of pain intensity according to the NRS at different times: 
preoperative and at the 1st, 2nd, 12th and 24th postoperative hours. 
 
• Secondary objectives  
Postoperative opioid consumption and comparison of total cumulative consumption 
between the two groups.  
It will also evaluated the degree of sensory and motor block, the easy of performance 
of the anesthetic technique,  the degree of patient satisfaction and the record of short-
term complications (first 24 hours post-intervention): hematoma, pruritus, nausea 
and/or vomiting. 
 
 
STUDY TYPE 
An observational study of paired cohorts, not randomized, is designed in two hospitals 
in northern Spain in the period between october 2023 and september 2024. 
 
 
 
 

 
PROTOCOL 
 
All patients will be trained preoperatively in pain assessment using a Numerical Rating 
Scale (NRS) from 0 (absence of pain) to 10 (maximum pain endured). All patients will  
receive the same anesthesia and analgesia protocol; fentanyl, propofol and 
rocuronium prior to intubation. 
Anesthetic maintenance with 1 MAC of sevoflurane and boluses of muscle relaxant 
and fentanyl if there is an increase >20% in blood pressure or above baseline heart 
rate. The anesthetic protocol will include analgesia with 1 g of paracetamol and 50 mg 
of dexketoprofen every 8 hours and a bolus of 0.1 mg/kg of intravenous 
dexamethasone. When the patient reporte an NRS > 3 and functional impact, 
intravenous morphine will be administered at a dose of 0.04 mg/kg every 10 minutes 
until NRS < 3 in the PACU and tramadol 1 mg/kg in the ward. The nursing staff and the 
anesthesiologist in charge of the PACU will be blind to the block received by the 
patient in each study group. 
Before general anesthesia, patients will be assigned to one of the study groups 
depending on the anesthesiologist responsible for performing the blocks. 
SHAC + SSN Group (anterior approach): with the patient in the supine position and the 
arm placed in abduction and slight external rotation the ultrasound probe will be 
positioned in the transverse axis between the coracoid process and the humeral head. 
After identifying the tendon of the subscapularis muscle, a puncture will be performed 
in a lateral to medial plane and the local anesthetic will be deposited at two levels; one 
deep to the subscapularis tendon at the pericapsular level of the glenohumeral joint (5 
ml of ropivacaine 0.2%), and another in withdrawal at about the level of the fascia that 
separates the subscapularis and deltoid muscles at a more superficial level (10 ml of 
0.2% ropivacaine). Subsequently, the ultrasound probe will be positioned in the 
transverse axis at level with the neck to locate the suprascapular nerve through an 
anterior approach as it ran beneath the omohyoid muscle. After hydrodissecting the 
correct plane with saline solution 5 ml of 0.2% ropivacaine will be administered, 
depositing the local anesthetic under the lower belly of the omohyoid muscle. 

SSN + AN group (posterior approach): with the patient in a sitting position and the 
arm placed in a neutral position, with slight internal rotation supported on the 
abdomen, the ultrasound probe will be positioned in the supraspinous fossa and a first 
puncture of the suprascapular nerve will be performed posteriorly, level with the 
supraspinous fossa. Next, the probe will be positioned at the level of Velpeau's 
quadrilateral and a second puncture of the axillary nerve will be performed, taking the 
posterior humeral circumflex artery as a sonoanatomical reference in the plane of 
intersection formed by the deltoid, triceps brachii, and teres minor muscles. After 
locating the planes by hydrodissection with saline solution 10 ml of 0.2% ropivacaine 
will be administered to each of the nerves. 
 
MATERIAL AND METHODS 
1.1 Definition of study subjects 
 
The inclusion criteria: being over 18 years of age, ASA physical status I – III and having 
been scheduled for shoulder arthroscopy surgery. 
The exclusion criteria: any contraindication for performing regional anesthetic 
techniques (infection at the puncture point, alteration of hemostasis, allergy to local 
anesthetics, patient refusal to participate in the study, inability to evaluate 
postoperative pain, known neuropathy of the operated limb and patients who 
required conversion to open surgery). 
 
RECRUITMENT AND RECRUITMENT OF PARTICIPANTS 
The anesthesiologist responsible for the operating room performed both the block of 
the anterior capsule of the shoulder and the suprascapular nerve via the anterior route 
and the blocks of the suprascapular and axillary nerves via the posterior route until the 
number of patients established in each of the groups is reached.  
 
 
 

 
JUSTIFICATION OF SAMPLE SIZE 
 
Because no work of this nature has been carried out previously, a sample size 
calculation will be not performed and all patients who underwent surgery in the 12 
months that the study data collection will last were consecutively included in the 
study. 
 
VARIABLES EVALUATED 
The main variable will be the measurement of pain intensity according to the NRS at 
different times: preoperative and at the 1st, 2nd, 12th and 24th postoperative hours. 
As secondary variables, postoperative opioid requirements will be assessed in the form 
of intravenous morphine, measured in mg (only during the 2 hours of the patient's stay 
in the Postanesthesia Care Unit), and tramadol (mg) up to 24 hours postoperatively. 
The degree of sensory block will be also assessed by a cold sensitivity test with a 
cotton swab dipped in cold water applied to the skin of the upper third of the arm, 
which will be graded with a sensitive scale going from 0 to 2 (2 being normal sensitivity 
to cold, 1 hypoesthesia and 0 anesthesia). The degree of motor block upon arrival at 
the PACU will be assessed by the movement of the arm using a simple numerical scale 
(0 = cannot raise the extended arm > 45º and 1 = can raise the extended arm > 45º), 
the ease of performance of the corresponding anesthetic technique by the 
anesthesiologist using a simple verbal scale (easy/medium difficulty/difficult), the 
appearance of adverse effects (postoperative nausea and/or vomiting, hematoma, 
pruritus, urinary retention), the degree of patient satisfaction (very satisfied, satisfied 
or dissatisfied) and the notification of complications related to the anesthetic 
techniques performed. 
 
 
 
 

STATISTICAL ANALYSIS PLAN 
Continuous quantitative variables will be expressed as mean and standard deviation 
and the results will be contrasted using the Student's T test if normality criteria will be 
met, failing which they will be expressed as median and range and contrasted using 
the Mann Whitney´s U. The qualitative variables will be expressed in absolute numbers 
and relative frequencies and the results of both groups will be contrasted using the Chi 
square. In addition, Fisher's test will be applied when necessary. Normality tests will be 
conducted for all continuous quantitative variables. The Kruskal-Wallis technique will 
be also employed with post-hoc application of the Bonferroni test for the analyses. The 
data will be processed using SPSS software version 19.0 (IBM Corporation, Armonk, 
NY, USA), assuming a p-value below 0.05 as significant. 
 
SCHEDULE AND EXPECTED COMPLETION DATE.  
 
The study will be carried out between october 2023 and june 2024. 
 
 
 
ETHICAL-LEGAL ASPECTS 
 
All data collected will be managed in accordance with the regulations established by 
Organic Law 3/2018, of December 5, on the Protection of Personal Data and guarantee 
of digital rights; such as 14/2007 of July 3, on Biomedical Research; such as the 
Standards of Good Clinical Practice, Declaration of Helsinki, as well as the Oviedo 
Convention. 
The study protocol and all associated documentation will be submitted for evaluation 
to the CAEI of Galicia. Any modification to the initial approved protocol will be sent for 
re-evaluation.  
 Researchers assume the commitment to make public the results of their research, 
whether positive or negative. 
Since this is an anonymous survey, informed consent will not be necessary.  

 
RISKS.  
Participation in this study does not imply an increased risk since it is a cross-sectional 
study, which will not interfere with the daily activities of the center in terms of clinical 
and therapeutic management of patients. The study will be carried out in accordance 
with local regulations and applicable laws and following internationally accepted 
ethical standards. 
 
CONFIDENTIALITY OF THE INFORMATION COLLECTED IN THE CONTEXT OF THE 
STUDY.  
 
The study research staff will ensure that the pseudonymization of participants is 
maintained. Which will be identified through a code in the electronic database, with all 
their information associated with this code and not with their personal data. This 
database will be stored on a service computer, access to which is password protected. 
Additionally, the database will also be protected by a password. This information will 
be stored securely and will only be accessible to members of the research team and 
authorized personnel.  
The questionnaire to obtain the data will use the Microsoft Form platform and when 
the information is provided to the research team it will be coded and pseudonymized, 
making it untraceable and respecting the privacy of the data provided. 
 
The person responsible for the processing and custody of the data will in all cases be 
the principal investigator of the study.  
At the end of the study, the data will be stored in the institutional online repository of 
the Department of Health and Sergas RUNA for a minimum of 10 years, under a 
password that only the main researcher will have access to in Excel format that will be 
protected with a different password. also with only access for the main researcher. 
In the future, if these data are required for subsequent studies, consent must be 
sought from the principal investigator. 
 
 

 
COMMITMENT TO PUBLISH RESULTS 
Researchers must make the commitment to make the results of their research public, 
whether positive or negative. 
 
ECONOMIC REPORT AND SOURCE OF FINANCING 
This project does not have financing. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

 
BIBLIOGRAPHY 
 
1. 
Checcucci G, Allegra A, Bigazzi P, Gianesello L, Ceruso M, Gritti G. A new 
technique for regional anesthesia for arthroscopic shoulder surgery based on a 
suprascapular nerve block and an axillary nerve block: an evaluation of the first results. 
Arthroscopy 2008;24:689–96.  
2. 
Stiglitz Y, Gosselin O, Sedaghatian J, Sirveaux F, Molé D. Pain after shoulder 
arthroscopy: a prospective study on 231 cases. Orthop Traumatol Surg Res. 
2011;97(3):260-6.  
3. 
Marhofer P, Anderl W, Heuberer P, Fritz M, Kimberger O, Marhofer D, Klug W, 
Blasl J. A retrospective analysis of 509 consecutive interscalene catheter insertions for 
ambulatory surgery. Anaesthesia. 2015;70(1):41-6.  
4. 
Sgroi TA, Cilenti M. Rotator cuff repair: post-operative rehabilitation concepts. 
Curr Rev Musculoskelet Med. 2018;11(1):86-91.  
5. 
Novoa-Boldo A, Gulotta LV. Expectations Following Rotator Cuff Surgery. Curr 
Rev Musculoskelet Med. 2018;11(1):162-166.  
6. 
Toma O, Persoons B, Pogatzki-Zahn E, Van de Velde M, Joshi GP; PROSPECT 
Working Group collaborators. PROSPECT guideline for rotator cuff repair surgery: 
systematic 
review 
and 
procedure-specific 
postoperative 
pain 
management 
recommendations. Anaesthesia. 2019;74(10):1320-1331.  
7. 
Hurley ET, Maye AB, Thompson K, Anil U, Resad S, Virk M, Strauss EJ, Alaia MJ, 
Campbell KA. Pain Control After Shoulder Arthroscopy: A Systematic Review of 
Randomized Controlled Trials With a Network Meta-analysis. Am J Sports Med. 
2021;49(8):2262-2271.  
 
 
 
 
 
 
 

 
 ANNEXES 
 
INFORMED CONSENT 
 
TITLE OF THE STUDY 
 
Prospective observational study on the analgesic effectiveness of blocking the 
shoulder´s anterior capsule and the suprascapular nerve by the anterior approach 
versus blocking of the suprascapular and axillary nerves by the posterior approach in 
shoulder arthroscopy. 
 
This document is intended to provide you with information about a research study in 
which you are invited to participate. This study was approved by the Galician Research 
Ethics Committee. 
If you decide to participate in it, you must receive information from the researcher, 
read this document first and ask all the questions you need to understand the details 
about it. If you wish, you can take the document, consult it with other people, and take 
the time necessary to decide whether to participate or not.  
Participation in this study is completely voluntary. You can decide not to participate or, 
it is accepted, change your mind by withdrawing consent at any time without giving 
any reason. We assure you that this decision will not affect your relationship with your 
doctor or the healthcare to which you are entitled.  
What is the purpose of the study? 
To collect information about the analgesic efficacy of anterior shoulder capsule and 
suprascapular nerve block versus posterior suprascapular and axillary nerve block in 
shoulder arthroscopy. 
Why are they offering me to participate?  
You are invited to participate because we want to know your experience and 
knowledge in analgesic management in the arthroscopic shoulder surgery to which you 
are going to undergo. 
 

What does my participation consist of?  
First of all, you will have answered some questions to determine if you meet the 
requirements of the study. Once you have been selected you will be informed of the 
procedure so you can collaborate in it. It will not involve collecting samples of 
biological fluids or performing tests in addition to those usual for good clinical practice. 
Once in the ante-operating room, we proceed to achieve an anxiolytic level with 
comfort for the patient to be able to perform the regional technique. Once a good 
anxiolytic level has been acquired, an ultrasound-guided puncture is performed and, 
through one or two punctures, for the administration of local anesthesia with the aim 
of blocking the aforementioned nerves. The fundamental objective is to achieve a 
good analgesic level without residual motor blockade. The patient may notice local 
discomfort derived from the diffusion of the local anesthetic, such as residual motor 
blockage or altered sensitivity, but these are usually temporary. 
Your participation in the study will imply acceptance of completing questionnaires and 
using the results.  
This data collection will be carried out by answering a questionnaire and does not 
imply any additional activity.  
Your participation in it will involve completing questionnaires that would take about 10 
minutes. 
What discomforts or inconveniences does my participation have?  
Your participation does not imply additional inconveniences to those of normal care 
practice except the time spent having to respond to a survey.  
Will I get any benefits for participating?  
You are not expected to obtain direct benefit from participating in the study. The 
research aims to discover unknown or unclear aspects about the clinical practice and 
care management of acute pain. This information may be useful in the future for other 
people.  
Will I receive the information obtained from the study?  
If you wish, you will be provided with a summary of the results of the study.  
Will the results of this study be published?  

The results of this study will be submitted to scientific publications for their 
dissemination, but no data that could lead to the identification of the participants will 
be transmitted.  
How will the confidentiality of my data be protected?  
The obtaining, processing, conservation, communication and transfer of your data will 
be done in accordance with the provisions of the General Data Protection Regulation 
(EU Regulation 2016-679 of the European Parliament and of the Council, of April 27, 
2016) and the regulations Spanish on protection of personal data in force (Organic Law 
3/2018, of December 5, on Protection of Personal Data and guarantee of digital rights). 
The institution in which this research is carried out is responsible for the processing of 
your data, and may contact the Data Protection Delegate through the following 
means: email: dpd@sergas.es  
The data necessary to carry out this study will be collected and stored in 
pseudonymized (encrypted) mode. Pseudonymization is the processing of personal 
data in such a way that they cannot be attributed to a data subject without the use of 
additional information. In this study, only the research team will know the code that 
will allow them to know their identity. 
The regulations that regulate the processing of personal data give you the right to 
access your data, object, correct it, cancel it, limit its processing, restrict or request its 
deletion. You can also request a copy of these or for it to be sent to a third party (right 
of portability).  
To exercise these rights, you can contact the Data Protection Delegate of the center 
through the contact methods indicated above or the main researchers of this study. 
Likewise, you have the right to file a claim with the Spanish Data Protection Agency, 
when you consider that any of your rights has not been respected.  
Only the research team and the health authorities, who have the duty to maintain 
confidentiality, they will have access to all the data collected by the study. Information 
that cannot be identified may be transmitted to third parties. In the event that any 
information is transmitted to other countries, it will be done with a level of data 
protection equivalent, at least, to that established by Spanish and European 
regulations.  

At the end of the study, or the established legal period, the data collected will be kept 
anonymous for use in future research according to what you choose on the consent 
signature sheet.  
Are there financial interests in this study?  
The researcher will not receive specific remuneration for their dedication to the study. 
You will not be compensated for participating.  
Thank you very much for your collaboration 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

CONSENT DOCUMENT FOR PARTICIPATION IN A RESEARCH STUDY 
PATIENT'S WRITTEN INFORMED CONSENT 
 
TITLE OF THE STUDY: PROSPECTIVE OBSERVATIONAL STUDY ON THE ANALGESIC 
EFFECTIVENESS OF BLOCKING THE SHOWLDER’S ANTERIOR CAPSULE AND THE 
SUPRASCAPULAR NERVE BY THE ANTERIOR APPROACH, VERSUS BLOCKING OF THE 
SUPRASCAPULAR AND AXILLARY NERVES BY THE POSTERIOR APPROACH IN SHOULDER 
ARTHROSCOPY 
 
 
 
 
I, _________________________________ 
□ I have read the information sheet that has been given to me. 
□ I have been able to ask questions about the study. 
□ I have received sufficient information about the study. 
□ I have spoken with: _______________________________ 
□ I have had sufficient time to adequately consider my participation in the study. 
□ I understand that my participation is voluntary. 
□ I understand that I can withdraw from the study: 
.- whenever you want. 
.- without having to give explanations. 
.- without this affecting my medical care. 
 
I freely give my consent to participate in the study and give my consent for the access and use 
of my data under the conditions detailed in the information sheet. 
 
………………………...........  
 
 
………………………............ 
Signature of patients 
 
 
              Signature of researcher 
Date: ____/____/____  
 
 
Date: ____/____/____ 
 
 
 
 
 
 
 
…………………………………… 
Signature of the legal representative, 
family member or person linked in fact 
Date: ____/____/____ 
 
 
 
 
 
 
 
 
 
 

 
FORMULATION FOR REVOCATION OF INFORMED CONSENT 
 
I,  Mr/Mrs ................................................. with DNI…...…........................ Through this channel I 
wish to inform my decision to withdraw from this research protocol for the following reasons:: 
(This 
section 
is 
optional 
and 
can 
be 
left 
blank 
if 
the 
patient 
so 
wishes)………………………………………………………………………………………………………………………………………
…………… 
on behalf of Mr/Mrs …………….....................……………… 
 
 
………………………............  
………………………...........  
………………………........... 
Signature of patients 
   Signature of the legal representative,  Signature of researcher 
 
Date: ____/____/____ 
Date:____/____/____ 
Date:____/____/____