A Prospective Observational Study of the Efficacy of Combined Interscalene Block and Superficial Cervical Plexus Block using Peripheral Nerve Stimulator and Landmark-Based Technique, as a Sole Anesthetic for Surgeries on the Clavicle in the COVID-19 Pandemic.

Background: Fractures of the clavicle are usually operated under general anesthesia (GA) as they need dense anesthesia, and the airway is difficult to access intraoperatively. There is no established regional anesthesia (RA) technique for clavicular fractures, also as the innervation is contentious. Some studies have been done using RA techniques, but they are all small case numbers. RA is superior to GA in many ways, and we wished to avoid GA specifically during the COVID-19 pandemic. Aims: This study aimed to use a peripheral nerve stimulator and a landmark-based technique to give interscalene block (ISB) and superficial cervical plexus block (SCPB) as a sole anesthetic for clavicular fracture surgeries during the COVID-19 pandemic. Settings and Design: This was a prospective observational study in a tertiary care teaching hospital in eastern India. Materials and
Methods: After approval from our ethics committee and informed consent, thirty patients of American Society of Anesthesiologists Class I or II, aged 18-65 years, after exclusion criteria were selected who had to undergo clavicular surgery. Three 10-mL syringes were made, each with 5 mL of 0.75% ropivacaine, 2 mL of 2% lignocaine with 1:200,000 adrenaline, and 3 mL of saline. Using the HNS Stimuplex (B. Braun Melsungen AG, Melsungen, Germany) nerve stimulator, 20 mL was given for an ISB and 5 mL for the SCPB. RA was considered successful if there was no conversion to GA and surgery could be performed.
Results: With an onset time of 6.53 ± 2.17 min, good operating conditions were obtained in all our patients. Horner's syndrome was noted in two patients. Surgery was successfully carried out in all thirty patients under RA. Pain relief lasted postoperatively for 5 ± 0.92 h.
Conclusion: ISB combined with SCPB is safe and effective as a sole anesthetic for clavicular surgery. We successfully avoided the use of a general anesthetic in these patients during the COVID-19 pandemic and gave them a safe and effective alternative. Copyright:

INTRODUCTION

Operations for fractures of the clavicle are usually performed under general anesthesia (GA) as it requires dense anesthesia. It is usually done in a semi-sitting position where the airway is difficult to access intraoperatively.[1]

GA is associated with inherent problems of hemodynamic stress response, delayed ambulation, high opiate use, and postoperative nausea and vomiting (PONV).

On the other hand, no regional anesthesia (RA) technique is established as a routinely used sole anesthetic for fractures of the clavicle. The innervation of the clavicle is still controversial and attributed to either the cervical or the brachial plexus.[2] Hence, any single block is usually not enough for complete coverage of clavicular surgical pain.[3] There are only a few isolated case reports of RA use for this purpose, in pregnancy, and in patients with comorbidities such as morbid obesity and morphine allergy.[45]

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.[146] Ultrasound for RA is still not available in many centers in India, whereas a peripheral nerve stimulator (PNS) usually is.

We planned to study the use of a PNS and a landmark-based technique, to provide effective anesthesia, using interscalene block (ISB) and superficial cervical plexus block (SCPB), in order to avoid GA. RA entails less costs and faster ambulation both at rest and during movement.

Common side effects of ISB include hoarseness of voice, Horner's syndrome, and phrenic nerve palsy temporarily. Other rarer complications include infection; epidural, spinal, or intravascular injections related to the approach chosen; and nerve injuries which are extremely rare.[7] Careful attention to technique is needed to avoid these.

We started this study right at the beginning of the COVID-19 pandemic. There was a flurry of guidelines at that time, but we realized that under the circumstances, using RA would give us some important advantages.[8] We are a resource-limited setup. Drugs and personnel are valuable resources during a pandemic. Both are preserved with RA over GA. We would limit the exposure of health workers and anesthetists to patients with active COVID-19. Oxygen was a scarce resource at one point, not to be squandered away irresponsibly if we had a safe alternative. By opting for RA, we were conserving personal protective equipment and avoiding airway manipulation and infectious contamination of the environment (an aerosol-generating procedure [AGP]). Getting adequate postoperative analgesia and less risk to caregivers were other perceived benefits.

Avoiding GA in patients with active COVID-19 was also an attractive option. There were reports that besides the risk to the anesthetist, mortality rates of patients with undiagnosed COVID-19 who undergo surgery are higher.[9]

MATERIALS AND METHODS

This was a prospective observational study conducted during April 2021–March 2022 in a tertiary care hospital in eastern India and was approved by the institutional ethics committee.

Thirty patients of American Society of Anesthesiologists (ASA) Classes I and II, of either sex, aged 18–65 years undergoing clavicular surgeries were enrolled for the study. The study protocol was explained to all the patients, and written informed consent was obtained.

The exclusion criteria were as follows: patients refusing to give consent, refusing regional blocks, local infection at the puncture site, coagulopathy, pregnant females, history of allergy to local anesthetics used, psychiatric and neurological disease, and patients with severe obstructive or restrictive lung disease.

All patients were operated on only if they were COVID-19 reverse transcriptase–polymerase chain reaction negative.

Preanesthetic evaluation of all patients was done the night before on the wards. A clinical history and physical examination were carried out. Necessary laboratory and radiological investigations were done. Tablet lorazepam 1 mg was given at night for anxiolysis.

The technique of the nerve blocks and the Numerical Rating Scale (NRS) for assessment of pain was explained to the patients. Informed consent was then obtained in a language the patient understood.

Anesthesia technique

An 18G intravenous (i.v.) line was secured in all patients on the nonoperative site, and lactated Ringer's solution was started before surgery.

Pulse oximetry, electrocardiogram, and noninvasive blood pressure were attached, and baseline parameters were noted.

Three 10-mL syringes were prepared, thus each containing 5 mL of 0.75% ropivacaine, 2 mL of 2% lignocaine with 1:200,000 adrenaline, and 3 mL of normal saline.

The interscalene block

Patients were placed in supine position, and the head was turned away from the side to be blocked. The landmarks: clavicular head of sternocleidomastoid, interscalene groove, and clavicle were identified and marked [Figure 1]. The patient was asked to sniff, which makes palpation and recognition of the groove easier. The skin was cleaned with antiseptic solution (chlorhexidine) and draped. A low interscalene approach was used. The block can be considered a cross between a classic ISB and a supraclavicular block.[10] The point of entry is two fingers above the clavicle in the interscalene groove. After anesthetizing the skin at the point of entry with 2 mL of 2% lignocaine, a 5-cm insulated Stimuplex (Stimuplex HNS12, B. Braun Melsungen AG, Melsungen, Germany) needle was inserted almost perpendicular to the skin and directed slightly caudad. Insertion is lower than the classic approach. The brachial plexus is very superficial, about 2 cm in this location. The nerve stimulator Stimuplex (Stimuplex HNS12, B. Braun Melsungen AG, Germany) PNS was initially set to deliver 1.2 mA (2 Hz, 100 μs). The needle was advanced slowly. Motor response of the brachial plexus (pectoralis, deltoid, triceps, or biceps response) was accepted as a successful localization of the brachial plexus. The response disappeared at 0.4 mA.

Figure 1

Interscalene block

Twenty milliliters of the above prepared local anesthetic solution was injected very slowly, after careful and frequent aspirations, 3 mL at a time, by experienced operators making sure not to inject if there were high injection pressures.

The superficial cervical plexus block

The posterior border of the sternocleidomastoid muscle was 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 was inserted perpendicularly, 3 mL injected at 0.5 cm depth and transversely, and 2–3 mL injected both cephalad and caudad to the point of insertion, (total 5 mL) subcutaneously along the border [Figure 2].

Figure 2

Superficial cervical plexus block

Onset of anesthesia, i.e., inability to raise the arm, loss of motor power, and sensation to cold and pinprick over the C3, C4, and C5 dermatomes were recorded. Side effects such as Horner's syndrome and hoarseness of the voice were noted. All medications given intraoperatively were recorded. RA was considered successful if there was no conversion to GA.

Patients were sedated with midazolam (0.02 mg.kg−1). Oxygen 2–4 L.min−1 was administered through a nasal cannula. Patients were kept warm with drapes covering head to avoid shivering. Intraoperative use of pneumatic equipment close to the patient's ear can result in noise levels over 100 dB, and significant sedation is needed to mask this noise.[11]

Perioperative NRS scores, pulse, BP, and SpO2 were recorded. The first NRS score was noted at 15 min after the last injection, then hourly till the end of surgery. Duration of postoperative analgesia was assessed as the time from injection of local anesthetic to the request for analgesic by the patient on the ward. Worst NRS scores were noted on operative day (D0).

RESULTS

Results are summarized in Tables 1 and 2.

Table 1

Patient demographics

Characteristics	Value
Age (years), mean±SD	42.9±15.27
Height (cm), mean±SD	157±8
Weight (kg), mean±SD	66±7
Male/female	21/9
ORIF/implant removal (lateral/midshaft/medial)	12/16/2

ORIF=Open reduction and internal fixation, SD=Standard deviation

Table 2

Outcomes of surgery and anesthesia

Parameters	Mean±SD
Onset of anesthesia (min)	6.53±2.17
Duration of surgery (min)	2.48±0.59
Duration of analgesia (h)	5±0.982
Complications	Horner’s in 2 patients
Conversion to GA	0

GA=General anesthesia, SD=Standard deviation

DISCUSSION

Our results were that with an onset of action of 6.53 ± 2.17 min, we had good anesthetic conditions in all of our thirty patients. A couple of patients needed some extra sedation with dexmedetomidine 1 μg.min−1, and some subperiosteal local anesthetic infiltration was done by the surgeons [Figure 3]. There were no side effects in any of the patients. However, Horner's syndrome was noted in two patients. We received positive feedback from our surgeons, and analgesia lasted for an average of 5 ± 0.982 h after which our patients received other forms of analgesia. This correlates with the findings of Reverdy, showing that ISB and SCPB give surgical anesthesia. It can be used as an alternative to a GA.[1]

Figure 3

Surgery on clavicle

Reverdy in 2015 performed SCPB and ISB to anesthetize 12 patients for clavicle fracture surgery. Using 20 mL of anesthetic-mepivacaine 1% in seven patients and ropivacaine 0.75% in five patients, they report successful completion of surgery and ample postoperative analgesia for 24 h.

Contractor et al. in 2016 did US-guided SCPB and ISB in thirty ASA PS Classes I and II patients undergoing clavicular surgery. They successfully completed surgery of the clavicle without any major complications.[12]

A retrospective observational study was done by Balaban et al. in 2017. It involved 12 patients undergoing clavicular fracture surgery. They were given combined SCPB and ISB. Surgical anesthesia was achieved in all of their patients with no major complications.[13]

The volume of local anesthetic used in our study was 25 mL (20 mL for ISB and 5 mL for SCPB). This is similar to the volumes used by Kaciroglu et al. They have used 15 mL of local anesthetic for ISB and 10 mL for SCPB.[6] Banerjee et al. in 2019 used 16 mL of local anesthetic for ISB and 10 mL for SCPB.[14] Reverdy have used 20 mL of local anesthetic for a C5-C6 root block.[1] Balaban et al. in 2018 used 10–20 mL of 0.5% bupivacaine for a ISB and SCPB. The lower volumes of local anesthetic they used for ISB may be because they had an ultrasound-guided technique, whereas we had a PNS.[13] A similar volume as ours has been used by Potsangbam and Kay, although they have used an ultrasound technique.[15]

Potsangbam and Kay did a prospective observational study in 12 patients posted for clavicular surgery in 2019, who were given RA for clavicular surgery using 30 mL of local anesthetic mixture (bupivacaine 5% and lignocaine 1% in 1:1 ratio). They concluded that this technique of RA as a sole anesthetic is effective for clavicular surgeries. They had good postoperative analgesia and no significant complications.[15]

Kaciroglu et al. in 2019 concluded that ISB provides analgesia for proximal humerus, shoulder joint, and lateral two-third of clavicle.[6]

Analgesic efficacy of the ISB in lateral and middle clavicle shaft fractures is also strongly suggested by Olofsson et al.[16] They performed a prospective enrollment of fifty patients for GA with ISB for surgical fixation of middle and lateral clavicle fractures and compared them with a historical control of 76 retrospective patients without regional block. The authors concluded that the group with ISB had significantly lower postoperative morphine consumption.

SpO2, pulse rate, systolic blood pressure, and diastolic blood pressure were maintained in the normal range in all of our patients.

We found that postoperative pain relief lasted for a median time of 5 ± 0.982 h. The mean maximum NRS at D0 was 2 (range 0–3). Postoperative analgesia was in the form of paracetamol 1 g i.v. With or without intramuscular diclofenac 75 mg.

None of our patients had any side effects although Horner's syndrome was noticed in two patients, which was self-limiting and wore off. This corroborates with the findings of Contractor et al. in whose study eight out of thirty patients developed Horner's syndrome.[12]

The innervation of the clavicle is contentious,[2] and various combinations of blocks have been used for analgesia, with or without a general anesthetic. We have used a low variation of the ISB and combined it with a SCPB.

All studies done so far have used ultrasound-guided blocks, but there are not too many studies using a PNS which is much more widely available and affordable. Using a meticulous technique with careful precautions, this method could make it accessible to more patients. Our study suggests that this form of RA is safe, is easy to implement, and provides excellent opioid-sparing postoperative analgesia too.

Fractures of the clavicle have traditionally been performed under GA as it requires dense anesthesia and is usually done in a semi-sitting position which renders the perioperative airway access difficult.

GA is associated with problems of hemodynamic stress response, delayed ambulation, high opiate use, and PONV. We wanted to avoid GA wherever possible, and this gained further relevance and impetus during the COVID-19 pandemic.

Anesthetists are a high-risk category even when vaccinated and potentially risk contagion. There is a high likelihood of spread of COVID-19 to other previously uninfected patients. By reducing airway manipulation and AGPs, RA reduces this risk significantly.[17]

Indeed, the European and American Societies of RA have produced joint COVID-19 recommendations. They advise that RA should be preferred over GA whenever possible. The Royal College of Anaesthetists and Association of Anaesthetists of Great Britain and Ireland also recommend using local or RA where practicable and safe in order to preserve key drugs required during the critical care of COVID-19 patients.[817]

Limitations of our study

Lower volumes of local anesthetic may be used with ultrasound-guided blocks.[18] Larger numbers and randomized controlled trials need to be done to see the overall safety over GA. Having two groups, one with RA and one without, will allow rigorous comparison of variables such as total analgesic consumption, pain control at rest, and mobilization and overall patient satisfaction. The time from block to surgical incision may be slightly longer in RA when compared to GA.[14]

CONCLUSION

We conclude that combined ISB and SCPB are safe and effective as a sole anesthetic for clavicular surgery. It may offer several advantages in places where GA might need to be avoided as in high-risk cases and especially in the COVID-19 pandemic in low-resource settings.

Further randomized controlled trials may show its superiority over GA for clavicular surgeries.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.