An interventional study of SPENG Block and Superior Trunk Block in Shoulder Arthroscopic Surgery, Upper Extremity and Humerus Fractures, sponsored by Bursa Yuksek Ihtisas Training and Research Hospital. Not yet recruiting at 1 site in Turkey (Türkiye). Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-11-13.
Sponsored by Bursa Yuksek Ihtisas Training and Research Hospital · Not applicable, Interventional, and Treatment
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Shoulder and upper extremity surgery causes severe postoperative pain. The interscalene brachial plexus block is the standard regional analgesia technique, but it causes ipsilateral hemidiaphragmatic paralysis (HDP) in almost all patients because of its proximity to the phrenic nerve. This can lead to dyspnea, hypoxemia, and atelectasis, especially in obese, elderly, or respiratory-compromised patients. The superior trunk block (STB) has been proposed as a phrenic-sparing alternative, yet HDP still occurs in about 70-76% of patients.
The Shoulder Posterior Pericapsular Nerve Group (SPENG) block is a novel pericapsular technique that targets the articular branches of the suprascapular and axillary nerves with a single injection posterior to the scapula, far from the brachial plexus and phrenic nerve. No randomized controlled trial has yet compared the SPENG block with the STB.
The aim of this prospective, randomized controlled trial is to compare preoperative ultrasound-guided SPENG block and STB in adult patients undergoing elective shoulder and upper extremity surgery under general anesthesia. The primary outcome is the incidence of hemidiaphragmatic paralysis, assessed by M-mode ultrasound measurement of diaphragmatic excursion in the post-anesthesia care unit. Secondary outcomes include intraoperative mechanical power and respiratory mechanics, intraoperative nociception (qNOX) and additional opioid requirement, Visual Analog Scale (VAS) pain scores and rescue analgesic consumption during the first 24 postoperative hours, and patient satisfaction.
The investigators hypothesize that the SPENG block will significantly reduce the incidence of hemidiaphragmatic paralysis compared with the STB while providing similar analgesic quality during the first 24 postoperative hours.
Rationale
After superior trunk block (STB), hemidiaphragmatic paralysis (HDP) has been reported in 76.3% of patients (Kang et al., Anesthesiology 2019) and in 70.8% of patients with 20 mL of local anesthetic (Lee et al., Pain Physician 2021). Even after ultrasound-guided supraclavicular block, the reported HDP incidence is 59.5% (Ferré et al., 2019). These data suggest that all approaches at the level of the brachial plexus carry a substantial risk of phrenic nerve involvement. The SPENG block (Kilicaslan et al., Pain Med 2026) targets the articular branches of the suprascapular and axillary nerves, which provide approximately 70% of the sensory innervation of the shoulder joint, at a site posterior to the scapula. M-mode ultrasound assessment of diaphragmatic excursion is a non-invasive, repeatable, and objective bedside method for detecting block-related HDP.
Randomization and Blinding Procedures
The allocation sequence will be generated by computer (www.random.org) and concealed in sequentially numbered, opaque, sealed envelopes. Each envelope will be opened immediately before the block by the anesthesiologist performing it, who will not be involved in data collection. To maintain blinding, identical sterile dressings will be applied to both the supraclavicular region and the posterior shoulder in all patients. All block procedures will be performed with real-time needle-tip visualization, in 5 mL increments with aspiration before each increment. Lipid emulsion (20%) and resuscitation equipment will be available.
Standardized Perioperative Management
Standard monitoring will be applied in all patients. IV midazolam 1-2 mg may be given after baseline diaphragm measurement. Anesthesia will be induced with propofol 2-2.5 mg/kg, fentanyl 1 µg/kg, and rocuronium 0.6 mg/kg, and maintained with sevoflurane titrated to a qCON of 40-60. Fentanyl 0.5 µg/kg will be administered if qNOX remains above 60 for more than 1 minute. All patients will receive IV paracetamol 1 g and ondansetron 4 mg 30 minutes before the end of surgery. Ventilation will be standardized in volume-controlled mode (tidal volume 6-8 mL/kg ideal body weight, PEEP 5 cmH₂O, FiO₂ 50%, respiratory rate adjusted to EtCO₂ 35-40 mmHg). Plateau pressure will be measured with a 0.5-second inspiratory pause, and mechanical power will be calculated with the simplified Gattinoni formula: MP (J/min) = 0.098 × RR × VT (L) × [Ppeak - ½ × (Pplat - PEEP)]. Postoperative analgesia will consist of IV paracetamol 1 g every 6 hours and IV dexketoprofen 50 mg every 12 hours unless contraindicated, with IV tramadol 1 mg/kg (maximum 400 mg/24 h) as rescue analgesia.
Diaphragm Ultrasound Technique
The ipsilateral hemidiaphragm will be imaged in the supine position with a 2-5 MHz convex probe using a subcostal approach along the anterior axillary/midclavicular line (liver window on the right, spleen window on the left). Excursion will be measured three times in M-mode during each maneuver, and the mean value will be recorded. The postoperative measurement will be performed when the patient is fully awake and cooperative (Modified Aldrete score ≥9), using the same position, probe placement, and maneuvers, by the same blinded assessor.
Sample Size and Statistical Analysis
Sample size was calculated with G*Power 3.1.9.7 based on the primary outcome. Assuming an HDP incidence of 70% with STB and a conservatively estimated 30% with SPENG, 31 patients per group are required (two-sided α = 0.05, power = 90%). Allowing for an anticipated 15% loss, 36 patients will be enrolled per group. This sample size is also sufficient to detect a 1.5-point (SD 2.0) difference in VAS scores with 80% power. Data will be analyzed with SPSS v26.0. Relative risk with 95% confidence interval will be reported for the primary outcome. Repeated measures ANOVA or linear mixed-effects models will be used for time-dependent variables, and Kaplan-Meier analysis with the log-rank test for time to first rescue analgesic. Analyses will follow a modified intention-to-treat approach, and p \< 0.05 will be considered statistically significant.
106 studies on the registry are indexed under Humeral Fractures; 20 are open to participants now.
This study's planned enrollment of 72 is above the median of 56 across 64 interventional studies indexed under Humeral Fractures.
Browse Humeral Fractures studies →Bursa Yuksek Ihtisas Training and Research Hospital is the lead sponsor of 53 studies on the registry; 23 are open to participants now.
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Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
The anaesthetists’ scale of health before surgery: I is healthy, II has a mild illness that is under control, III a severe one, IV a severe illness that is a constant threat to life. V and VI are used for the critically ill and for organ donors.
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Blood tests of how long blood takes to clot. The INR is the prothrombin time (PT) put on a common scale; about 1 is usual for someone not taking a blood thinner.
Criteria often make an exception for people on a blood thinner such as warfarin, whose INR is raised on purpose.
Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.
Chronic obstructive pulmonary disease: long-term lung disease that makes it hard to breathe out, including emphysema and chronic bronchitis.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
ASA physical status
The anaesthetists’ scale of health before surgery: I is healthy, II has a mild illness that is under control, III a severe one, IV a severe illness that is a constant threat to life. V and VI are used for the critically ill and for organ donors.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraindication
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
INR, PT and aPTT (clotting tests)
Blood tests of how long blood takes to clot. The INR is the prothrombin time (PT) put on a common scale; about 1 is usual for someone not taking a blood thinner.
Criteria often make an exception for people on a blood thinner such as warfarin, whose INR is raised on purpose.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Platelets
Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
COPD
Chronic obstructive pulmonary disease: long-term lung disease that makes it hard to breathe out, including emphysema and chronic bronchitis.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Participants will receive an ultrasound-guided Shoulder Posterior Pericapsular Nerve Group (SPENG) block with 20 mL of 0.25% bupivacaine before induction of general anesthesia.
Procedure: SPENG Block
Participants will receive an ultrasound-guided superior trunk block with 20 mL of 0.25% bupivacaine before induction of general anesthesia.
Procedure: Superior Trunk Block
With the patient in the lateral decubitus position, a linear probe is placed transversely just inferior to the posterior acromion. Using an in-plane medial-to-lateral approach, the needle tip is positioned between the posterior glenoid rim and the deep surface of the infraspinatus muscle, and 20 mL of 0.25% bupivacaine is injected as a single injection.
With the patient supine and the head turned to the contralateral side, the superior trunk is identified at the level just proximal to the origin of the suprascapular nerve. Using an in-plane lateral-to-medial approach, 20 mL of 0.25% bupivacaine is injected, half anterior and half posterior to the superior trunk.
Incidence of Hemidiaphragmatic Paralysis
Ipsilateral diaphragmatic excursion will be measured with M-mode ultrasound during the sniff maneuver (mean of three measurements). Hemidiaphragmatic paralysis is defined as a ≥25% reduction in excursion from baseline and graded as none (\<25%), partial (25-75%), or complete (\>75% reduction or paradoxical movement).
Time frame: Baseline (before block) and approximately 30 minutes after admission to the post-anesthesia care unit
Change in Diaphragmatic Excursion
Percentage change in ipsilateral diaphragmatic excursion (mm) measured with M-mode ultrasound during quiet breathing, deep inspiration, and sniff maneuver, calculated as ((T0 - T1) / T0) × 100.
Time frame: Baseline (before block) and approximately 30 minutes after admission to the post-anesthesia care unit
Intraoperative Mechanical Power
Mechanical power (J/min) calculated with the simplified Gattinoni formula: 0.098 × RR × VT (L) × \[Ppeak - ½ × (Pplat - PEEP)\].
Time frame: 10 minutes after intubation, after surgical positioning, at 30 and 60 minutes of surgery, and at the end of surgery
Intraoperative Driving Pressure and Static Compliance
Driving pressure (Pplat - PEEP, cmH2O) and static compliance (VT / \[Pplat - PEEP\], mL/cmH2O).
Time frame: 10 minutes after intubation, after surgical positioning, at 30 and 60 minutes of surgery, and at the end of surgery
Intraoperative Nociception (qNOX)
qNOX values recorded with the Conox monitor and the percentage of anesthesia time with qNOX \>60.
Time frame: Before induction, at intubation, surgical positioning, skin incision/first portal entry, every 15 minutes during surgery, and at the end of surgery
Intraoperative Supplemental Fentanyl Consumption
Total supplemental fentanyl (µg) and number of supplemental doses administered for qNOX \>60 lasting longer than 1 minute.
Time frame: Intraoperative period
Postoperative Pain Scores
Pain assessed with the Visual Analog Scale (0-10 cm; 0 = no pain, 10 = worst imaginable pain) at rest at all time points, and additionally during movement at 24 hours.
Time frame: On arrival at the post-anesthesia care unit, at 30 minutes, and at 2, 4, 6, 12, and 24 hours postoperatively
Time to First Rescue Analgesic
Time (minutes) from the end of surgery to the first administration of rescue tramadol for VAS ≥4.
Time frame: Postoperative 24 hours
Total Rescue Tramadol Consumption
Total intravenous tramadol (mg) administered as rescue analgesia.
Time frame: Postoperative 24 hours
Patient Satisfaction
Assessed with a 5-point Likert scale (1 = very dissatisfied, 5 = very satisfied).
Time frame: Postoperative 24 hours
Incidence of Block-Related Adverse Events
Horner syndrome, hoarseness, vascular puncture, signs of local anesthetic systemic toxicity, postoperative nausea and vomiting, paresthesia, dyspnea, and need for supplemental oxygen.
Time frame: Postoperative 24 hours
Block Performance Time
Total time (minutes) for ultrasound imaging and needling.
Time frame: During block procedure
Motor Block of the Shoulder
Shoulder abduction (axillary nerve) and external rotation (suprascapular nerve) strength assessed with a 3-point scale (2 = normal strength, 1 = reduced strength, 0 = no movement against gravity).
Time frame: 20 minutes after block
Plan to share: No — Individual participant data will not be shared, as the informed consent form does not include permission for data sharing and the Turkish Personal Data Protection Law (KVKK) restricts the disclosure of personal health data. Aggregated results will be published in a peer-reviewed journal.
Start is estimated for Dec 2026; primary completion for Sep 2027, 9 months later.
Of 26 interventional studies with no phase under Humeral Fractures, half reached primary completion within 46 months of starting (the median), counting those still running; a quarter within 13 and three quarters within 50. This study's planned 9 months is below that.
How these figures are worked out, and which studies are left out of them.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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Bursa Yuksek Ihtisas Training and Research Hospital