Upper limb surgeries, including those involving the forearm and hand, can be effectively performed under both general and regional anaesthesia. However, general anaesthesia is often associated with complications such as airway manipulation risks, hemodynamic instability, and postoperative nausea and vomiting. In contrast, regional anaesthesia techniques, particularly brachial plexus blocks, offer several advantages including improved perioperative analgesia, reduced systemic side effects, and better patient satisfaction.

Among the approaches to brachial plexus blockade, the supraclavicular and infraclavicular routes are widely practiced. The supraclavicular approach provides dense anaesthesia of the upper limb and is historically considered effective, as initially described by Kulenkampff and Persy [1]. However, it is associated with potential complications like pneumothorax, hemidiaphragmatic paresis, and inadvertent nerve blocks such as of the recurrent laryngeal nerve or cervicothoracic sympathetic chain [4–7]. Ultrasound guidance has significantly enhanced the safety and success rates of this approach by allowing real-time visualization of anatomy, drug spread, and needle trajectory [2,3].

The infraclavicular approach, particularly using the coracoid technique, is advantageous for surgeries distal to the shoulder. It offers a lower risk of pneumothorax and minimal phrenic nerve involvement, likely due to local anaesthetic spread being confined below the clavicle [8,9]. It has been shown to provide better postoperative outcomes, including less nausea and vomiting, more effective analgesia, and faster discharge readiness when compared to general anaesthesia [8].

Comparative studies have produced mixed results. Some report higher block success rates with infraclavicular blocks (93%) than supraclavicular blocks (78%) [10], while others find supraclavicular blocks are faster to perform [11]. In terms of efficacy and nerve coverage, infraclavicular blocks may offer more complete ulnar and musculocutaneous nerve blockade [12,13,14]. Ultrasound guidance has further refined both techniques, with studies confirming improved block performance and safety [15–18].

Therefore, this study aims to directly compare the block characteristics, performance times, and complications of ultrasound-guided supraclavicular and infraclavicular brachial plexus blocks in patients undergoing forearm and hand surgeries. The findings will contribute to informed clinical decision-making and optimization of regional anaesthesia techniques in upper limb surgeries.

Study Design: This was an observational comparative study conducted in the Department of Anaesthesiology, Government Medical College, Thiruvananthapuram. The objective was to compare the effectiveness and safety of ultrasound-guided supraclavicular and infraclavicular brachial plexus blocks in patients undergoing orthopedic surgeries of the forearm and hand.

Study Population: The study included patients aged 18 to 65 years belonging to the American Society of Anesthesiologists (ASA) physical status grades I and II, scheduled for orthopedic procedures on the forearm and hand. These patients were recruited consecutively from the hospital's orthopedic operating list.

Sample Size Calculation: Based on a pre-calculated estimate, the sample size was determined to be 166 patients. Patients fulfilling the inclusion criteria were enrolled consecutively until the sample size was achieved.

Grouping and Intervention: Patients were divided into two groups:

• Group S: Patients who received ultrasound-guided supraclavicular brachial plexus block.
• Group I: Patients who received ultrasound-guided infraclavicular brachial plexus block.

Patients were alternately assigned to each group. Each patient received 0.5 ml/kg of a local anesthetic mixture consisting of 0.5% bupivacaine and 2% lignocaine with adrenaline. Sensory and motor blocks were assessed using numerical scoring systems. Block performance time, effectiveness, and adverse events were recorded.

Inclusion Criteria

1. Patients of either gender aged 18–65 years.
2. ASA physical status I and II.

Exclusion Criteria

1. Patients refusing consent or uncooperative.
2. Those with neuropathies in the hand or forearm.
3.  
4. Pregnant women.
5. Clinically significant lung disease.
6. Local infection at the block site.
7. BMI > 35.

Study Period: The study was conducted over 1.5 years following approval by the Human Ethics Committee and Institutional Research Committee.

Outcome Variables

• Sensory Block: Assessed every 10 minutes for 30 minutes post-block using pinprick testing at territories of radial, median, ulnar, and musculocutaneous nerves. Scoring: 0 = pain, 1 = analgesia (no pain), 2 = anaesthesia (no pain, no touch).
• Motor Block: Assessed 30 minutes post-block at elbow, wrist, and hand grip using movements. Scoring: 0 = normal, 1 = paresis, 2 = paralysis.
• Complete Sensory Block: Score of 2 in all four nerve territories.
• Complete Motor Block: Score of 2 at all three joints.
• Effective Block: Defined as complete sensory and complete motor block.
• Block Performance Time: Time from needle insertion to removal.
• Adverse Events: Included vessel puncture (blood in needle), pneumothorax (confirmed by symptoms and chest X-ray), and Horner’s syndrome (ptosis, miosis).

DATA COLLECTION PROCEDURE

Patients were recruited after obtaining informed consent and pre-anesthetic evaluation. The study was conducted in the orthopedic OT. Baseline vitals including heart rate, blood pressure, ECG, and SpO₂ were recorded. Emergency equipment including a laryngoscope, suction apparatus, AMBU bag, and endotracheal tubes were kept ready.

Materials Used

• Ultrasound machine with linear probe (8–14 MHz)
• USG jelly and sterile probe cover
• 8 cm 18G and 22G needles
• 10 ml syringes
• Drugs: 0.5% bupivacaine, 2% lignocaine with adrenaline, Inj. Midazolam, Inj. Fentanyl, and emergency drugs

BLOCK TECHNIQUES

Supraclavicular Group (Group S): Patients were supine with arms adducted and head turned away from the block side. The USG probe was placed in a coronal oblique plane in the supraclavicular fossa, lateral to the sternocleidomastoid. After aseptic preparation and skin infiltration with 1–2 ml lignocaine, an 8 cm 18G needle was inserted in-plane. The brachial plexus (lateral to subclavian artery) was identified. The first 20 ml of anesthetic was injected inferolateral to the artery; the rest was injected superiorly after repositioning.

Infraclavicular Group (Group I): Patients were positioned supine with the arm abducted to 90° and elbow flexed. The USG probe was placed in the parasagittal plane over the deltopectoral groove to identify the axillary artery, vein, and cords of the plexus. An 8 cm 22G needle was used in-plane. The first 10 ml of anesthetic was injected posterior to the artery, 10 ml lateral to the artery, and the remaining volume between the artery and vein.

BLOCK ASSESSMENT

Sensory Block: Evaluated at 10-minute intervals for 30 minutes post-needle removal using pin-prick testing over radial, median, ulnar, and musculocutaneous nerve territories.

• 2: Anaesthesia
• 1: Analgesia
• 0: Pain

Motor Block: Assessed at 30 minutes post-block at elbow, wrist, and hand joints.

• 2: Paralysis
• 1: Paresis
• 0: Normal contraction

Complete and Effective Blocks: Complete sensory block: Score of 2 in all 4 nerve areas. Complete motor block: Score of 2 in all 3 joints. Effective block: Presence of both complete sensory and complete motor block.

BLOCK PERFORMANCE TIME

Block performance time was defined as the interval from the insertion of the needle to the withdrawal of the needle, as recorded using a stopwatch. This duration included the time taken to identify the target structures under ultrasound guidance, guide the needle into position, and inject the local anesthetic. Any difficulties encountered during this process, such as multiple needle passes or repositioning, were noted. This parameter served as an indicator of the ease and efficiency of the block technique.

ADVERSE EVENTS MONITORING

During and after the block procedure, patients were monitored for any signs of adverse events. These included:

• Vessel Puncture: Identified by aspiration of blood through the needle before or during injection.
• Pneumothorax: Suspected in the presence of symptoms like sudden chest pain, breathlessness, or desaturation. Confirmation was done via clinical examination and chest X-ray if required.
• Horner’s Syndrome: Diagnosed based on the presence of ptosis (drooping eyelid), miosis (pupil constriction), and anhidrosis on the affected side.

Any such adverse event was immediately managed as per standard protocols, and its occurrence was documented for analysis.

STATISTICAL ANALYSIS

Data collected were entered into Microsoft Excel and analyzed using the statistical software SPSS version 26. Continuous variables such as block performance time were expressed as mean ± standard deviation. Categorical variables, including sensory block, motor block, effectiveness of block, and incidence of adverse events, were presented as frequencies and percentages.

Comparisons between the supraclavicular and infraclavicular groups were made using appropriate statistical tests:

• The Chi-square test or Fisher’s exact test was used for categorical variables.
• The Independent sample t-test was used for normally distributed continuous variables.
• A p-value < 0.05 was considered statistically significant.

ETHICAL CONSIDERATIONS

The study was conducted after obtaining clearance from the Institutional Ethics Committee and Research Review Board. Informed written consent was obtained from all participants after explaining the nature of the study, the procedures involved, potential risks, and benefits. Confidentiality and anonymity were maintained throughout the study, and participants had the right to withdraw at any point without any impact on their standard of care.

A total of 166 patients aged between 18 and 65 years, who met the inclusion criteria and were scheduled for forearm and hand surgeries, were enrolled in the study. The patients were randomly allocated into two equal groups of 83 each. Demographic characteristics, duration of surgery, and surgical site were compared between the two groups.

• Group S: Patients who received an ultrasound-guided supraclavicular brachial plexus block.
• Group I: Patients who received an ultrasound-guided infraclavicular brachial plexus block.

Sensory and motor block assessments were conducted using a numerical scoring system—sensory block was evaluated at 10, 20, and 30 minutes post-intervention, while motor block was assessed at 30 minutes.

Table 1: Baseline Characteristics of Patients by Type of Block

In the supraclavicular group, ASA I and II patients were nearly equally distributed, whereas most patients in the infraclavicular group were ASA I. Age distribution showed older patients predominating in the supraclavicular group (>54 years: 42.2%), while the infraclavicular group had more younger patients (<29 years: 28.9%). Weight-wise, both groups mostly ranged between 60–80 kg, though the supraclavicular group had a higher proportion of patients under 60 kg. The majority of surgeries in both groups lasted between 1–2 hours, but longer durations (2–3 hours and >3 hours) were more common in the infraclavicular group. Regarding the area of surgery, forearm procedures predominated in both groups but were more frequent in the infraclavicular group (74.7%), while hand surgeries were relatively more common in the supraclavicular group (39.8%).

Table 2: Comparison of Supraclavicular vs Infraclavicular Blocks: Sensory & Motor Outcomes

At 30 minutes post-block, infraclavicular blocks demonstrated significantly better sensory blockade in the ulnar (P = 0.009) and median (P = 0.045) nerve distributions compared to supraclavicular blocks, suggesting superior efficacy in these regions. However, no significant difference was observed between the two groups in achieving sensory block in the radial (P = 0.756) and musculocutaneous (P = 0.205) nerves, indicating comparable performance for these nerves.

Table 3: Comparison of Supraclavicular vs. Infraclavicular Block – Complete Sensory, Motor, and Effective Upper Limb Block

The infraclavicular block resulted in a significantly higher proportion of patients achieving complete sensory block (94% vs. 79.5%, P = 0.006), complete motor block (94% vs. 79.5%, P = 0.006), and effective upper limb block (94% vs. 78.3%, P = 0.003) compared to the supraclavicular block.

 Table: 4: Motor Block of Elbow, Wrist, and Hand after Supraclavicular vs Infraclavicular Block

The results showed a statistically significant difference in the motor block of the elbow, with the infraclavicular block (mean = 1.916) being more effective than the supraclavicular block (mean = 1.771) (p = 0.014). However, no significant differences were observed between the two groups for the motor block of the wrist (p = 0.360) and hand (p = 0.417), indicating similar efficacy for both blocks in these regions.

Table 5: Need for Supplementation and Adverse Events

Regarding the need for supplementation, 94% of patients in the infraclavicular block group did not require any additional supplementation, compared to 78.3% in the supraclavicular block group. In terms of adverse events, 9 out of 83 patients in the supraclavicular block group experienced adverse events, with 7 cases of vascular puncture and 2 cases of pneumothorax. On the other hand, the infraclavicular block group had a much lower adverse event rate, with only 1 case of vascular puncture and no pneumothorax cases, indicating a safer profile for the infraclavicular block.

Ultrasound-guided brachial plexus blocks, including both supraclavicular and infraclavicular approaches, have significantly improved block success rates, localization accuracy, and safety profiles. This study aimed to compare the block characteristics, performance times, and complications associated with ultrasound-guided supraclavicular and infraclavicular brachial plexus blocks in forearm and hand surgeries.

The demographic data, surgical duration, and surgery sites were comparable across both groups. A majority of patients (61.4%) in the study belonged to ASA PS I, with the remaining 38.6% falling under ASA PS II. Among the supraclavicular block group, there was an almost equal distribution between ASA PS I and ASA PS II. Conversely, the infraclavicular block group had a higher proportion of ASA PS I patients (73.5%). The patient populations in terms of age, gender, weight, surgery duration, and site were comparable, ensuring balanced groups for analysis.

Our study found that the infraclavicular block provided a higher rate of effective upper limb blockade, defined as complete sensory and motor block. In this study, 94% of patients in the infraclavicular group had complete sensory and motor block, while only 78.3% in the supraclavicular group achieved this. These results align with previous studies such as those by Z. J. Koscielniak-Nielsen et al.¹⁵, which also reported higher success rates with infraclavicular blocks. Additionally, three randomized studies comparing the supraclavicular versus infraclavicular approach reported success rates between 85% and 95%, with infraclavicular blocks demonstrating consistently higher efficacy. Our 94% success rate in the infraclavicular group exceeds the 86% success rates reported in similar studies by Dingemans et al.¹⁹ and Sauter et al.¹⁸.

The higher success rate of the infraclavicular block may be attributable to the greater expertise required for its performance. Supraclavicular blocks are commonly performed at our institution, with varying skill levels among anaesthetists. In contrast, infraclavicular blocks are performed by anaesthetists with specialized ultrasound skills, which likely contributes to their higher success rate. The infraclavicular approach also appears to provide more effective blockade of the median and ulnar nerves compared to the supraclavicular approach, possibly due to more complete visualization and targeting of the brachial plexus components.

In terms of sensory block, the infraclavicular block showed superior results for both median and ulnar nerves. The mean sensory block scores for the ulnar and median nerves were significantly higher in the infraclavicular group compared to the supraclavicular group (1.916 vs. 1.675 for ulnar, and 1.928 vs. 1.795 for median nerve). This may be due to the higher incidence of nerve sparing (e.g., ulnar and median nerve sparing) observed in the supraclavicular group, resulting in suboptimal analgesia. In the infraclavicular group, no cases of ulnar or median nerve sparing were noted, although one case of radial nerve sparing occurred. These findings suggest that the infraclavicular block may provide a more consistent and reliable sensory and motor blockade.

Regarding block performance time, both groups demonstrated similar results, with the supraclavicular block taking 10.27 minutes and the infraclavicular block taking 10.65 minutes. These findings are consistent with previous studies such as Arcand et al.¹⁶, who reported block performance times of 4 and 4.7 minutes, respectively. However, in our institution, the slightly longer block performance times may be due to the variable experience of anaesthetists performing the blocks. In other studies, blocks were often performed by one or two highly experienced anaesthetists, which might account for the difference in time.

In terms of complications, the infraclavicular block had a significantly lower rate of adverse events compared to the supraclavicular block. Only 1.2% of patients in the infraclavicular group experienced vascular puncture, with no cases of pneumothorax, while 8.4% of patients in the supraclavicular group experienced vascular puncture and 2.4% experienced pneumothorax. The pneumothorax cases in the supraclavicular group were managed promptly with supplemental oxygen, chest X-rays, emergency surgery consultation, and chest tube insertion, highlighting the importance of prompt management in such cases. The proximity of the supraclavicular block to the pleura likely explains the higher risk of pneumothorax in this group. These findings are in agreement with studies by Loubert et al. and Williams et al.²¹, who concluded that while ultrasound guidance reduces the risk of complications, it does not eliminate them entirely. Additionally, Klastaad et al.²² reported that ultrasound-guided blocks do not completely eliminate the risk of nerve injury or pneumothorax, though they do reduce these risks.

The need for supplementary analgesia was higher in the supraclavicular block group (21.7%) compared to the infraclavicular group (6%). This finding mirrors the results of a randomized controlled trial by Ponnambalam Namasivayam et al.²³, which also found that the infraclavicular block required less supplementation.

In conclusion, this study, conducted with varying levels of anaesthetist experience, showed that the infraclavicular approach provided superior effectiveness, particularly in sensory and motor block of the median and ulnar nerves. The infraclavicular block also had a lower incidence of adverse events compared to the supraclavicular block. The block performance times were comparable between the two groups. Given the lower complication rates and higher block efficacy, the infraclavicular approach may be the preferred method for forearm and hand surgeries, especially in settings where minimizing complications is a priority.

Conflict of interest: Nil

1. Kulenkampff D, Persky MA. Brachia! plexus anaesthesia: Its indications, technic, and dangers. Ann Surg 1928;87:883.
2. Wilson JL, Brown DL, Wong GY. Infraclavicular brachia! plexus block: Parasagitta! anatomy important to the coracoid technique. Anesth Analg 1998; 87:870-873.
3. Franco CD, Domashevich V, Voronov G, et al. The supraclavicular block with a nerve stimulator: To decrease or not to decrease, that is the question. Anesth Analg 2004; 98:1167-1171.
4. Wilson JL, Brown DL, Wong GY. Infraclavicular brachia! plexus block: Parasagitta! anatomy important to the coracoid technique. Anesth Analg 1998; 87:870-873.
5. Yogen Asher; Hadzic's Peripheral Nerve Blocks and Anatomy for Ultrasound guided Regional Anaesthesia, Second Edition. Anesthesiology 2013; 119:493
6. Franco CD, Domashevich V, Voronov G, et al. The supraclavicular block with a nerve stimulator: To decrease or not to decrease, that is the question. Anesth Analg 2004; 98:1167-1171.
7. Franco CD, Domashevich V, Voronov G, et al. The supraclavicular block with a nerve stimulator: To decrease or not to decrease, that is the question. Anesth Analg 2004; 98:1167-1171.
8. Franco CD, Domashevich V, Voronov G, et al. The supraclavicular block with a nerve stimulator: To decrease or not to decrease, that is the question. Anesth Analg 2004; 98:1167-1171.
9. Brown DL, Cahill DR, Bridenbaugh LD. Supraclavicular nerve block: Anatomic analysis of a method to prevent pneumothorax. Anesth Analg 1993; 76:530-534.
10. Brown DL, Cahill DR, Bridenbaugh LD. Supraclavicular nerve block: Anatomic analysis of a method to prevent pneumothorax. Anesth Analg 1993; 76:530-534.
11. Clarkson CW, Hondeghem LM. Anesthesiology. 1985:62:396
12. Barrington MJ, Kluger R. Reg Anesth Pain Med. 2013:38:289-297
13. Ehab Farag and David L. Brown; Supraclavicular Block, Chapter 5; Wilson, Andy T. MBChB, FRCA, FICM Brown's Atlas of Regional Anaesthesia, 5th ed, Anaesthesia & Analgesia: July 2018 - Volume 127 ;45,48
14. A Comparison of Supraclavicular and Infraclavicular Block for Upper Extremity Surgery. Z. J. Koscielniak-Nielsen, B. S. Frederiksen, H. Rasmussen, L. Hesselbjerg. Published in Acta Anaesthesiologica Scandinavica/Volume 53, Issue 5.
15. Arcand G, Williams SR, Chouinard P, Boudreault D, Harris P, Ruel M, Girard F. Ultrasound-guided infraclavicular versus supraclavicular block. Anesth Analg 2005; 101:886-90.
16. Kapral S, Krafft P, Eibenberger K, Fitzgerald R, Gosch M, Weinstabl C. Ultrasound-guided supraclavicular approach for regional anaesthesia of the brachia! plexus. Anesth Analg 1994; 78: 507-13.
17. Williams SR, Chouinard P, Arcand G, Harris P, Ruel M, Boudreault D, Girard F. Ultrasound-guidance speeds execution and improves the quality of supraclavicular block. Anesth Analg 2003; 97: 1518-23
18. Dingemans E, Williams SR, Arcand G, Chouinard P, Harris P, Roul M, Girard F. Neurostimulation in ultrasoundguided infraclavicular block: a prospective randomized trial. Anesth Analg 2007; 104: 1275-80
19. Royse CF, Sha S, Soeding PF, Royse AG. Anatomical study of the brachia! plexus using surface ultrasound. Anaesth Intensive Care 2006; 34: 203-10.
20. De Jose Maria B, Banus E, Navarro Egea M, Serrano s, Perello M, Mabrok M ultrasound guided supraclavicular vs infraclavicular brachia! plexus blocks in children pediatric anaesthesia 2008; 18:838-44
21. Royse CF, Sha S, Soeding PF, Royse AG. Anatomical study of the brachia! plexus using surface ultrasound. Anaesth Intensive Care 2006; 34: 203-10.
22. Loubert C, Williams SR, Helie F et al. Complication during ultrasound guided regional block: accidental intravenous injection of local anaesthetic anaesthesiology 2008; 108; 759-760
23. Ponnambala Namasivayam, Vijaya anandh Mahendran ; A randomized controlled study comparing USG guided supra clavicular vs infra clavicular brachia! plexus block for upper limb surgeries vol 1, No I (2015)