Superficial Cervical Plexus Block Research Articles

A Clinical Study on Neck Surgeries Under Superficial Cervical Plexus Block as an Alternative to General Anesthesia in High-Risk Cases

A Clinical Study on Neck Surgeries Under Superficial Cervical Plexus Block as an Alternative to General Anesthesia in High-Risk Cases

Selective C5 nerve root block versus combined interscalene block for clavicle surgery

Objectives: The pain sensation of the clavicle is innervated by two separate plexuses. Regional anesthesia techniques for this area are challenging and complicated. Interscalene block, superficial cervical block, or a combination of these two is commonly used for regional anesthesia in clavicle surgery. The aim of this study was to investigate the efficacy of C5 nerve root block for clavicle surgery. Methods: Patients were divided into two groups: Group C5B (patients who received C5 nerve root block + superficial cervical plexus block) and Group ISB (patients who received interscalene block + superficial cervical plexus block). Motor block was assessed by the Medical Research Council Scale for Muscle Strength, while the sensory block of the areas corresponding to the nerve trace was assessed using the pinprick and cold testing. Furthermore, ultrasound was employed to evaluate phrenic nerve paralysis. Results: There was no difference between the groups in terms of mean age. The mean age of Group ISB was higher; however, the comparison of comorbidities revealed no significant difference between the groups. This statistically significant difference was clinically insignificant. Group C5B had lower 6-hour pain at rest, lower 0, 2, 4-hour pain on movement, and less postoperative analgesic consumption. Moreover, the time to first analgesic requirement was significantly longer in Group C5B. The motor examination of the peripheral nerves showed a significant difference in Group C5B. Conclusions: We are of the opinion that C5 nerve root block can be used instead of interscalene block since it does not produce a motor block in hand movements and preserves diaphragmatic functions. C5 nerve root block may therefore be considered an alternative to conventional interscalene block for clavicle surgery.

Ultrasound-guided superficial cervical plexus block reduces opioid consumption in patients undergoing craniotomy via suboccipital retrosigmoid approach: a randomized controlled trial

IntroductionThe effectiveness of superficial cervical plexus block (SCPB) at decreasing opioid use and improving hemodynamic stability during suboccipital retrosigmoid craniotomy has not been established. The aim of this study is...

Superficial cervical plexus block in Emergency Departments: rationale for its use in incision and drainage of neck skin abscesses.

Superficial cervical plexus block in Emergency Departments: rationale for its use in incision and drainage of neck skin abscesses.

Superficial cervical plexus block on pain control in patients with temporomandibular joint internal derangement with headache: a retrospective cohort study.

Temporomandibular disorders (TMDs) are a group of disorders with varied pathophysiology and clinical manifestations. Masticatory and cervical motor systems have a functional relationship. Superficial cervical muscles have greater hyperactivity in myogenous and mixed TMDs than in healthy individuals, demonstrating an abnormal pattern of contraction. This study aimed to demonstrate the effects of superficial cervical plexus block (SCPB) anesthesia during arthrocentesis in patients with temporomandibular joint (TMJ) internal derangement and headache. This retrospective cohort study included 2 men and 23 women with cervicogenic headache and TMJ internal derangement treated by arthrocentesis, and 40 TMJs with established cervicogenic headaches. The average follow-up period was 9.36 ± 2.679 months. TMJ and muscle pain during mastication, maximum and non-assisted mouth opening, and lateral excursion were recorded. Pain and dysfunction were determined using the visual analog scale. Patients were monitored before, during, and after arthrocentesis while inducing SCPB anesthesia, and vital findings were recorded. In addition, skin surface temperature was measured. Patients experienced a significant increase in their clinical values. Changes in non-assisted mouth opening (mean from 29.65 ± 6.31 to 33.3 ± 5.21 mm) (P < .05), assisted mouth opening (mean from 38.98 ± 7.62 to 43.35 ± 6.17 mm), right excursions (mean from 7.28 ± 2.08 to 9.13 ± 1.86 mm), and left excursions (mean from 7.48 ± 1.71 to 8.90 ± 1.82 mm) were statistically significant (P < .05). Patients were relieved after SCPB, resulting in decreased pain and hemodynamic values. Increase in mean temperature after SCPB was statistically significant (P = .002, P < .05). This study presents a straightforward novel protocol, clinically efficient for arthrocentesis on pain control in patients with TMJ internal derangement and cervicogenic headache.

The strategy of non-intubated spontaneous ventilation anesthesia for upper tracheal surgery: a retrospective case series study.

BackgroundUpper tracheal surgery is used to treat patients who with tracheal tumors or tracheal stenosis. The non-intubated spontaneous ventilation anesthesia (NSVA) may have advantages over endotracheal intubation and surgical cross-field intubation in upper tracheal surgery. This study aimed to illustrate and assess the feasibility of NSVA strategy for upper tracheal surgery.MethodsThis is a retrospective case series study in which 51 patients (from May 2015 to August 2020) who met the criteria in NSVA strategy were analyzed. Anesthesia was performed using total intravenous anesthesia (TIVA) combined with bilateral superficial cervical plexus block (CPB) or thoracic epidural anesthesia (TEA). Patients received spontaneous ventilation through laryngeal mask airway (LMA) during the surgery. Anesthesia conversion technique was applied to patients who met the anesthesia conversion criteria.ResultsIn total, 51 patients met the NSVA criteria and were included in this study. Forty-six out of 51 patients (90%) had TIVA + bilateral superficial CPB and five patients (10%) had TIVA + TEA + CPB. During the airway-opened period, 46 patients had stable spontaneous ventilation. Five patients need anesthesia conversion, two patients had high-frequency ventilation (HFV), and three patients required cross-field intubation. Postoperative complications occurred in seven (14%) patients, no reintubation was needed after surgery. The median postoperative hospital stay was 6.31±4.30 days.ConclusionsThis NSVA strategy includes criteria for patient selection, preoperative assessment, surgical technique, airway management, criteria and technique for anesthesia conversion. The NSVA strategy is a feasible procedure in upper tracheal surgery.

Superficial Cervical Plexus Block for Retroauricular Mass Excision in a Patient with High Risk of General Anaesthesia: A Case Report.

The surgical procedure of lipomas is performed under local, regional, or general anaesthesia depending on the location, number, and size of the lipoma. Anaesthesia can be achieved with a superficial cervical plexus block in the short-term surgery of soft tissue lesions in the dermatome areas of the lesser occipital nerve and great auricular nerve. In this article, we presented a high-risk patient with comorbid diseases and difficult airway who underwent superficial cervical plexus block for retro-auricular lipoma excision.

Bilateral superficial cervical plexus block with conscious sedation for thyroid surgery

Total thyroidectomy can safely be performed by bilateral superficial cervical plexus blockade which is a regional anesthetic technique to anaesthetize superficial branches of the anterior primary rami of cervical 3-5 spinal nerves. Conscious sedation with this anesthetic technique enhance safe and faster recovery compared to general anesthesia (GA) with endotracheal intubation which is traditionally employed technique for thyroidectomy. This randomized active control trial was conducted in the department of Anaesthesia, Analgesia and Intensive care medicine, Bangabandhu Sheikh Mujib Medical University from January to December 2018 to compare perioperative outcome between bilateral superficial cervical plexus blockade and GA technique during total thyroidectomy. Total 60 patients of American Society of Anesthesiol- ogists Classification grade I and II who were selected for thyroidectomy were randomly divided into Group-A(n=30) and Group-B (n=30). Group A received with 0.5% bupivacaine and 1% lignocaine; and group B received general anesthesia during total thyroidectomy. Heart rate, systolic blood pressure, diastolic blood pressure mean arterial blood pressure , oxygen satura- tion (SPO2) were recorded and compared between the groups. Operative site bleeding, surgeon’s satisfaction &amp; post operative pain were measured with Boezaart Scoring system, Likert scale &amp; visual analogue scale repectively; and compared between two groups. During induction, systolic and diastolic blood pressure were high in group B and reduced in group A which were statistically significant. Systolic and diastolic blood pressure was significantly reduced in Group-A in comparison to Group-B after 5 minutes, 30 minutes, 45 minutes and at the end of operation. Bilateral superficial cervical plexus blockade reduced pain more effective- ly than GA group &amp; it was statistically significant. Mean value of bleeding score were also statis- tically significant in Group-A. Regarding surgeons’ satisfaction, there was no statistically signif- icant difference between the groups. Bilateral superficial cervical plexus block with conscious sedation provided better outcome in terms of perioperative hemodynamics, pain and surgical site bleeding compared to general anaesthesia. BSMMU J 2021; 14(4): 104-108

Efficacy of superficial cervical plexus block versus cervical retrolaminar block both combined with auriculotemporal nerve block in parotid surgeries

BackgroundRegional techniques in parotid surgeries include superficial cervical plexus block (SCPB) and auriculotemporal nerve (ATN) block, which can be used as an anesthetic technique for awake parotidectomy. This study aimed to evaluate the efficacy of cervical retrolaminar block (RLB) as an alternative to SCPB both, used in combination with auriculotemporal nerve (ATN) block, in parotid surgery. Material and methodsA total of 40 patients undergoing parotid surgery were prospectively randomized into either the SCPB group (n = 20) or the cervical RLB group (n = 20) using 20 ml of 0.25% bupivacaine plus 5 mcg\\mL epinephrine. Both were combined with ATN block using 5 ml of 0.25% bupivacaine plus 5 mcg\\mL epinephrine. ResultsThe time to first request for analgesia was longer in the RLB group than the SCPB group. Total intra operative fentanyl consumption and post-operative pethidine consumption in the first 24h were lower in group RLB. All patients (n = 20) in the SCPB group required rescue analgesia using pethidine, while only 40% of patients required pethidine in the RLB group. Visual analog scale was lower in the RLB group from 2 to 24-h post-operatively, but it was associated with hypotension and longer block technique time occurred with RLB than SCPB. There was no significant difference in side effects except for 20% Horner's syndrome in the SCPB group. ConclusionCervical RLB is more effective analgesic technique than SCPB, as the cervical RLB showed longer time to first analgesic request, lower intraoperative anesthetic consumption, lower total post-operative pethidine consumption and lower VAS.

Abstract No.: ABS3728: Effectiveness of superficial cervical plexus block in anterior cervical spine discectomy and fixation surgeries under general anaesthesia

Background and Aims:Superficial cervical plexus block can provide analgesia in head and neck surgeries. This study aimed to assess the effectiveness of superficial cervical plexus block in patients undergoing elective anterior cervical discectomy or fixation surgeries under general anaesthesia with respect to intraoperative and postoperative haemodynamic status and quality of analgesia.Methods:60 American Society of Anesthesiologists physical class-I,II patients scheduled for cervical discectomy and fixation surgeries under general anaesthesia were randomised into two groups. Group-A received ipsilateral superficial cervical plexus block using 10ml injectionbupivacaine(0.25%) post-induction of general anaesthesia. Group-B received no block but received supplemental intravenous analgesics for haemodynamic response to skin incision (if any). Intraoperatively, heart rate, systolic and diastolic blood pressure, supplemental analgesics usage and postoperatively, visual analogue(VAS) scores to pain were monitored . Induction and maintenance of anaesthesia and supplemental analgesics were standardised.Results:Both groups had comparable , baseline heart rate, systolic and diastolic blood pressure. However, following skin incision, there was significant rise in heart rate, systolic and diastolic blood pressure and requirement of supplemental analgesics in group-B when compared to group-a (p<0.05). Statistically insignificant changes in heart rate, systolic and diastolic blood pressure from baseline were noted within group-A (p<0.05). Patients in group-B had higher VAS scores postoperatively needing more supplemental intravenous analgesics compared to group-A (figure 1).Figure 1Visual analogue scale(VAS) scores between the groups at different time pointsConclusion:Ipsilateral superficial cervical plexus block is a simple, safe and effective preemptive analgesic technique in patients undergoing cervical spine discectomy and fixation surgeries under general anaesthesia.

Abstract No.: ABS1074 : Evaluation of efficacy of superficial cervical plexus block for surgeries in head and neck region: A comparative randomised control study

Background and Aims:Superficial cervical plexus block can provide analgesia in head and neck surgeries. This study aimed to evaluate analgesic efficacy of superficial cervical plexus block (SCPB) in various head and neck surgeries, with the primary objectives of assessing time to first rescue analgesic, total dose of rescue analgesics in 24 hours, intraoperative analgesic requirement and associated perioperative complications.Methods:Sixty patients of American Society of Anesthesiologists physical class II,III (30 patients in each group) were included. Group A received general anaesthesia(GA) with systemic analgesia and group B received GA followed by SCPB with injection bupivacaine 0.25% 10ml on each side according to site of surgery. Visual analogue scale(VAS) scores, intra and postoperative analgesic requirement in 24 hours, time of first rescue analgesic demand and peri-operative complications were noted. All quantitative data were analysed by student-t test and qualitative data was analysed by chi-square test.Results:Time of first rescue analgesia was earlier and intraoperative fentanyl requirement and postoperative total rescue analgesic requirement were higher in group A (32.33+_38.39, 38.33+_12.61, 2566.667 + _504.006) than group B(1092+_396.55 minutes, 10.66+_13.11, 833.33+_874.28 ) with p value <0.001 (table 1,2). No significant complication was noted in any patient.Conclusion:SCPB provides better perioperative analgesia and decreases intraoperative as well as postoperative analgesic requirements and associated side effects with no significant perioperative complications in various head and neck surgeries.

Regional anesthesia as a safe anesthesia technique for clavicle surgery in a COVID-19 positive patient at rural setup: A case report.

IntroductionClavicle fractures are less commonly managed under regional anesthesia compared to general anesthesia. The study highlights the advantage of regional anesthesia in reducing the risk of aerosol generation and viral transmission during the times of COVID-19 and avoiding the complications associated with general anesthesia.Presentation of caseWe report a case of 42 years old COVID-19 positive male with a left clavicle fracture due to a fall from a tree, who was managed under regional anesthesia with open reduction and internal fixation. A combination of interscalene brachial plexus and superficial cervical plexus block was performed.DiscussionThe dual innervation of the clavicle makes combined interscalene brachial plexus and superficial cervical plexus block an effective method of anesthesia for clavicle surgery. It provides better analgesia, has fewer postoperative complications, less infection transmission via aerosol, and earlier hospital discharge as compared to general anesthesia.ConclusionUltrasound-guided combined interscalene brachial plexus and superficial cervical plexus block can be used as a safe anesthetic technique in clavicle surgery.

Effect of Bilateral Superficial Cervical Plexus Block on Postoperative Analgesic Consumption in Patients Undergoing Thyroid Surgery.

PurposePatients complain of moderate-intensity pain following thyroid surgery. Superficial cervical plexus block (SCPB) can be employed as a component of multimodal analgesia after thyroid surgery. This double-blind, randomized study aimed to compare the effects of bilateral SCPB (BSCPB) on postoperative analgesic requirements following thyroid surgery.MethodsA total of 60 American Society of Anesthesiologists (ASA) I-II patients who underwent elective total thyroidectomy under general anesthesia were randomly assigned to Group 1 and Group 2. After inducing general anesthesia, BSCPB was not administered to Group 1, whereas BSCPB was administered using a three-point injection technique with 0.5% levobupivacaine in Group 2. Patient-controlled analgesia (PCA) was applied by using tramadol in both groups for postoperative analgesia. Tenoxicam was administered as rescue analgesic to patients in case of numeric rating scale (NRS) >4. The postoperative consumption of tramadol, rescue analgesic requirement, and hoarseness, hematoma, signs of local anesthetic toxicity were recorded.ResultsThe consumption of tramadol for PCA at two, six, 12, and 24 hours postoperatively, NRS scores in the recovery room, and the number of patients who used tenoxicam as rescue analgesic were significantly lower in Group 2 than in Group 1. The hemodynamic values were similar between the groups.ConclusionsOur study demonstrates that BSCPB, when applied as a component of multimodal analgesia, is an effective method for reducing the analgesic requirements following thyroid surgery.

Depth of cervical plexus block and phrenic nerve blockade: a randomized trial

Background and objectivesCervical plexus blocks are commonly used to facilitate carotid endarterectomy (CEA) in the awake patient. These blocks can be divided into superficial, intermediate, and deep blocks by their...

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.

Ultrasound Guided Regional Anaesthesia for Breast Surgery in High Risk Patients- A Retrospective Observational Study

Introduction: Modified radical mastectomy (MRM) or breast conservative surgery (BCS) done under general anaesthesia (GA) in high-risk patients may be associated with significant morbidity, Intensive Care Unit stay and increased hospital stay leading to cost issues. In this case-series, we describe our experience with regional anesthesia for MRM or BCS and sentinel / complete axillary clearance in 61 patients with breast carcinoma who were high risk for perioperative complications in view of their co-morbidities. None required ICU or increased hospital stay postoperatively. Material &amp; Methods: Sixty-one ASA III/IV patients operated under regional anaesthesia for carcinoma of the breast were included. Multiple level USG guided thoracic paravertebral block (PVB), PECS block (1/2), Pecto-intercostal fascial block (PIFB), Serratus-anterior plane block (SAPB), brachial plexus block, Superficial cervical plexus blocks (SCPB), Erector spinae block (ESB) were given in different combinations. Result: There were 60 female patients (Age: 30-97 years) and 1 male patient (59 years) (Left side -27 patients, right side- 34 patients). Of the total 61 patients, 23 patients underwent BCS with axillary dissection, 36 patients underwent MRM with axillary dissection, 2 patients had MRM with Pectoralis Major muscle resection. Patients received different combinations of blocks PVB or ESB, PECS1/2 and SAPB. 43 patients received the PVB, 61 got the PECS1/2, 12 patients received ESP, 32 patients required SCPB, 1 infra-clavicular block and 35 patients got PIFB. All procedures were completed under regional anaesthesia with 51 patients getting intravenous midazolam (0.01-0.02mg/kg), 59 patients were given IV fentanyl (1-3ug/kg , 43 patients were given IV propofol (1-2mg/kg), These were given in small aliquots during the duration of the procedure. 2 patients had IV ketamine (0.5mg/kg) and 1 patient had IV dexmeditomidine (0.2-0.3ug/kg/hr). IV paracetamol, nonsteroidal anti-inflammatory drugs (NSAIDS) ie. Inj Diclofenac Sodium IV in the dose of 1mg/kg (max 75mg) were given when not contraindicated. There was single case of axillary hematoma with no other complications. No patient required ICU care postoperatively and were discharged as routine. Conclusion: A combination of blocks may be an option for surgical anaesthesia for breast surgeries in high risk patients. Careful planning, patient counseling and attention to toxic dose of local anaesthetics must always be considered. Keywords: Paravertebral block, Thoracic wall blocks, PECS block, Serratus Anterior plane block, Pecto-intercorstal fascial block, Superficial cervical plexus, Modified radical mastectomy, Breast conservative surgery.

Ultrasound-guided Maxillary Nerve Block and Superficial Cervical Plexus Block during Surgery for Maxillary Malignancy : A Case Report

Ultrasound-guided Maxillary Nerve Block and Superficial Cervical Plexus Block during Surgery for Maxillary Malignancy : A Case Report

A Study to Evaluate the Efficacy of Dexamethasone as an Adjuvant in Ultrasound-Guided Bilateral Superficial Cervical Plexus Block using 0.25% Bupivacaine in Patients Undergoing Thyroid Surgeries under Entropy-Guided General Anesthesia.

Context:Ultrasound-guided bilateral superficial cervical plexus block (BSCPB) is a technique described for thyroid surgeries for postoperative analgesia as the surgery can cause severe pain and discomfort. Perineural dexamethasone is known to prolong analgesic duration and reduce postoperative nausea/vomiting.Aims:To assess the efficacy of dexamethasone as an adjuvant to BSCPB with 0.25% bupivacaine on isoflurane consumption, intraoperative hemodynamic parameters, and postoperative analgesia in patients undergoing thyroid surgeries under general anesthesia.Settings and Design:This was a randomized control trial.Subjects and Methods:Eighty patients were randomized to two equal groups using random number table into Group A with BSCPB receiving 20 mL of 0.25% bupivacaine and Group B with BSCPB receiving 19 mL of 0.25% bupivacaine + injection dexamethasone 4 mg in the preinduction period. Hemodynamic parameters, isoflurane consumption, postoperative visual analog scale (VAS) score, and antiemetic effect over 24 h were compared between two groups.Statistical Analysis Used:Microsoft excel data sheet, Chi-square test, and independent t-test were used for statistical analysis.Results:The intraoperative hemodynamic parameters were comparable between the two groups. There was a significant difference in mean VAS score between two groups from 6 h to 20 h postoperatively. The time of rescue analgesic in Group A was 7.09 ± 1.04 min and Group was 13.19 ± 1.46 min with P < 0.0001. In Group A, 40% had nausea and 35% had vomiting, and in Group B, 7.5% had nausea and 5% had vomiting.Conclusions:Preinduction ultrasound-guided BSCPB with bupivacaine and dexamethasone provides longer duration of postoperative analgesia and lesser nausea and vomiting compared to bupivacaine alone.

Feasibility of Opioid-Free Anesthesia for Cervical Rib Excision: A Case Series and Review of Literature

AbstractBackground Perioperative pain management following cervical rib excision can be compounded in the background of chronic pain disorder caused by the neurovascular compression. The former mandates an enhanced analgesic requirement wherein the perioperative opioid use, in particular, can be associated with a peculiar adverse-effect profile and abuse potential. Appropriate to the context, an opioid-free anesthesia (OFA) protocol can be instrumental in minimizing the incidence of the aforementioned.Case Series While two patients necessitated OFA owing to opioid contraindication, the formulated protocol was evaluated in another six consecutive patients posted for elective cervical rib excision. A combined paravertebral block and superficial cervical plexus block was employed alongside general anesthesia. Intravenous dexmedetomidine and lignocaine assisted the conduct of OFA, and paracetamol dosing was continued into the postoperative period. Intraoperative rescue analgesia was ensured by a ketofol bolus (1:1 mixture of ketamine and propofol) whereas intravenous diclofenac was used for postoperative rescue analgesia.Results OFA could be successfully contemplated in all eight patients. A single bolus rescue dose of ketofol had to be administered in two patients intraoperatively and diclofenac had to be administered as postoperative rescue analgesic in two patients. There was no incidence of postoperative nausea/vomiting or any block-related complications. The postoperative stay was uneventful with an acceptable patient satisfaction.Conclusion The index experience reiterates the fact that a prudent combination of nonopioid multimodal analgesics with case-based locoregional techniques can feature as a successful OFA protocol, albeit mandating future prospective studies in this novel area of clinical interest.

The Effects of Ultrasound-guided and Anatomic landmark-based Superficial Cervical Plexus Block on Post-operative Pain Intensity in Thyroidectomy Patients: A Clinical Trial

The Effects of Ultrasound-guided and Anatomic landmark-based Superficial Cervical Plexus Block on Post-operative Pain Intensity in Thyroidectomy Patients: A Clinical Trial