PROJECT SUMMARY

Title:

A prospective observational study of the efficacy of combined Interscalene (ISB) and superficial cervical nerve block (SCPB), using peripheral nerve stimulator (PNS) and landmark based technique, as sole anaesthetic for surgeries on the clavicle.

Authors:

Dr Uma Majumdar (Assistant Professor) and Dr Anuradha Mitra (Assistant Professor), Department of Anaesthesiology, KPC Medical College and Hospital.

Rationale and Background information:

Fractures of the clavicle are usually performed under general anaesthesia (GA) as it requires dense anaesthesia and is usually done in a semi sitting position. GA is associated with problems of hemodynamic stress response, delayed ambulation, high opiate use, post-operative nausea and vomiting (PONV).

No regional anaesthesia (RA) technique is established as a routinely used sole anaesthetic for fractures of the clavicle. The innervation of the clavicle is still controversial and attributed to either the cervical or the brachial plexus. (1) Hence, any single block is usually not enough for complete coverage of clavicular surgical pain. There are only a few isolated case reports of regional anaesthesia use for this purpose, in pregnancy, and in patients with co-morbidities like morbid obesity, morphine allergy (2,3)

A handful of recent prospective observational studies have been undertaken in this direction, using ultrasound guidance, but they are all limited by small case numbers. (4,5) Contractor et al have a larger series as a prospective study. (6) There is one randomised controlled trial comparing GA with Interscalene block (ISB) plus cervical plexus block (SCPB) for fracture clavicle, using ultrasound guidance. (7) Ultrasound for regional anaesthesia is still not available in many centres in India, whereas a peripheral nerve stimulator usually is.

We plan to study the use of a peripheral nerve stimulator (PNS) and a landmark based technique, to provide effective anaesthesia, using an interscalene and a superficial cervical plexus block, in order to avoid GA. RA has less costs, faster ambulation, faster return to oral feeding and long lasting post-operative analgesia.

Common side effects include hoarseness of voice, Horner’s syndrome and phrenic nerve palsy. Other, rarer complications include infection, epidural, spinal or intravascular injections related to the approach chosen, and nerve injuries which are extremely rare. (8)

With careful attention to technique and scrupulous regard for safety, a combined interscalene(ISB) and cervical plexus block(SCPB), with a nerve stimulator and landmark technique can be an easy, effective and cheap way to benefit patients needing surgery on the clavicle, avoiding the complications of GA, especially in high risk patients who would do better with the avoidance of GA.

Aims and objectives

To study the efficacy of ISB and SCPB, using PNS and landmark based technique, as a sole anaesthetic for surgeries on the clavicle.

Methodology

Study Design: prospective observational study

Study setting: Orthopaedic Operation Theatre of KPC Medical College and Hospital, a tertiary care teaching hospital in Jadavpur, Kolkata

Study Period: For 6 months after ethical committee clearance.

Study population:30 patients

Inclusion Criteria: ASA 1 and 2 patients, age 18 to 65 years of age, undergoing surgeries on the clavicle

Exclusion Criteria: patients refusing to give consent, refusing regional blocks, local infection at the puncture site, coagulopathy, pregnant females, history of allergy to local anaesthetics used, psychiatric and neurological disease and patients with severe obstructive or restrictive lung disease.

Procedure:

A pre-anaesthetic check will be done on the previous day of surgery, with a detailed clinical history and physical examination. Laboratory investigations such as complete hemogram, bleeding time, clotting time, blood sugar, blood urea and creatinine, and electrocardiography will be routinely done in all cases. A Chest X-ray will be done to rule out pneumothorax, haemothorax or multiple ipsilateral rib fractures. All patients will be kept fasting overnight.

The procedure will be explained to the patient. An informed consent will be taken after explaining the procedure in detail to the patient, in a language understood by him and also explaining sedation and possible conversion to GA, in case it is necessary.

An 18 G intravenous line will be started preoperatively. All patients will be connected to electrocardiography, peripheral oxygen saturation (SpO2) and non-invasive blood pressure monitor.

Patients will be placed in supine position and the head will be turned away from the side to be blocked. The landmarks: clavicular head of sternocleidomastoid, interscalene groove and clavicle will be identified and marked. The patient will be asked to sniff, which makes palpation and recognition of the groove easier. The skin will be cleaned with antiseptic solution and draped. A low interscalene approach will be used. The block can be considered a cross between a classic interscalene block and a supraclavicular block. (8)The point of entry is 2 fingers above the clavicle in the interscalene groove. After anaesthetising the skin at the point of entry with 2ml of 2% lignocaine, a 5 cm, short bevel, 22 gauge insulated stimulating needle will be inserted almost perpendicular to the skin and slightly caudad. Insertion is lower than the classic approach, less than 2 cm depth since the brachial plexus is very superficial in this location (8). The nerve stimulator, PNS (Stimuplex HNS12) will be initially set to deliver 1.2 mA (2 Hz,100µsec). The needle will be advanced slowly. Once motor response of the brachial plexus is elicited (pectoralis, deltoid, triceps or biceps response) is accepted as a successful localization of the brachial plexus. The response should disappear at 0.4 mA.

About 12 to 15 ml of 0.75% Ropivacaine and 4 to 6 ml of 2% lignocaine with adrenaline (1:200,000) will be injected, very slowly, after careful and frequent aspirations, in divided dose, 3ml at a time, by an experienced operator making sure not to inject if there are high injection pressures.

After this injection, the superficial cervical plexus block will be given using landmarks.10 ml of local anaesthetic (5ml of 0.75% ropivacaine+ 2ml of 2% lignocaine with adrenaline (1:200,000) plus normal saline made upto 10ml). The posterior border of the sternocleidomastoid muscle will be identified and marked. At the midpoint along the posterior border of the muscle (midway between the mastoid and the head of the clavicle) a 23G needle will be inserted perpendicularly, 3ml injected at 0.5 cm depth and transversely, and 2-3ml injected both cephalad and caudad to the point of insertion, subcutaneously along the border.

Onset of anaesthesia ie; inability to raise the arm, loss of motor power and sensation to cold and pinprick over the C3, C4, C5 dermatomes will be recorded. Side effects like Horner’s syndrome and hoarseness of the voice will be noted. All medications given intraoperatively will be recorded. RA will be considered successful if there is no conversion to a GA. Perioperative VAS scores, pulse, BP, SpO2 will be recorded. First onset of pain, and need for analgesics (duration of pain relief) and worst VAS scores are noted on operative day (D₀) and post- operative day (D₁).

Patients will be sedated with midazolam (0.02mg/kg), and fentanyl (1-1.5µg/kg). Oxygen 2-4l/min will be administered through a nasal cannula. Patients will be kept warm with drapes covering head. Shivering will be avoided as will hyperhydration. Intraoperative use of pneumatic equipment close to the patient’s ear can result in noise levels over 100dB, and significant sedation is needed to mask this noise. (8). Dexmedetomidine infusions at 0.5µg/kg after loading doses will be used as necessary.

Ethical Issues

The peripheral nerve stimulator and landmark based technique, to provide effective local anaesthesia, is a well established technique with well documented safety profile, provided there is meticulous attention to technique, equipment and monitoring precautions. (8)

A detailed written consent will be taken from the patients explaining the pros and cons of the technique.

The data will be anonymized. Each patient will be identified by a serial number only.

The various operators will blinded to the final collation and analysis of data.

The data will be collected for research purposes only and not for any sort of commercial use.

References

1.Balaban O, Dülgeroğlu TC, Aydin T. Ultrasound-Guided Combined Interscalene-Cervical Plexus Block for Surgical Anesthesia in Clavicular Fractures: A Retrospective Observational Study. Anesthesiology Research and Practice, vol. 2018, Article ID7842128

2.Vandepitte C, Latmore M, O’Murchu E, Hadzic A, Van de Velde M Nijs S. Combined interscalene-superficial cervical plexus blocks for surgical repair of a clavicular fracture in a 15-week pregnant woman. Int J Obstet Anesth.2014 May;23(2):194-5.

3.Shanthanna H. Ultrasound guided selective cervical nerve root block and superficial cervical plexus block for surgeries on the clavicle. Indian J Anaesth.2014 May;58(3):327-9.

4.Reverdy F. Combined interscalene-superficial cervical plexus block for clavicle surgery: an easy technique to avoid general anaesthesia. BJA, vol.115, Issue eLetters Supplement,22 December 2015.

5.Potsangbam S, Kay JP. Efficacy of Combined Interscalene Block and Superficial Cervical Plexus Block for Surgeries of the Clavicle: A Prospective Observational Study. Journal of Clinical and Diagnostic Research.2019 February,vol.13(2): UC05-UC08

6.Contractor HU, Shah VA, Gajjar VA. Ultrasound guided superficial cervical plexus and interscalene brachial plexus block for clavicular surgery. Anaesth Pain Intensive Care 2016;20:447-50

7.Banerjee S, Acharya R, Sriramka B. Ultrasound-guided inter-scalene brachial plexus block with superficial cervical plexus block compared with general anaesthesia in patients undergoing clavicular surgery: A comparative analysis. Anest Essays Res 2019;13:149-54

8. Interscalene Brachial Plexus Block-Landmarks and Nerve Stimulator Technique- NYSORA