Unrelieved postoperative pain especially after orthopaedic surgery delays the patient’s eligibility for discharge, resulting in a prolonged hospital stay, inability to participate in rehabilitation programs, delayed recovery, poor functional outcome and greater use of health-care resources [1]. 

On the most basic level, severe pain can diminish the ability to accomplish postoperative goals, such as ambulation and participation in physical therapy, that are crucial to recovery after orthopaedic surgery. The link between poorly managed acute postoperative pain and increased long-term morbidity and mortality further underscores the consequences of poorly managed pain and the importance of providing the best possible pain control in these patients [2]. 

An ever-increasing number of lower limb surgeries, e.g., total knee arthroplasty, arthroscopic knee surgeries, lower limb fracture fixations and ankle and foot surgeries etc., demand better outcomes with minimal morbidity and mortality and early mobilization and discharge. The central neuraxial and regional anaesthesia and analgesia techniques significantly reduce perioperative morbidity and mortality [3]. 

Four-in-one block offers blockade of four nerves namely saphenous, obturator, sciatic nerves and nerves to vastus medialis. It can provide ease and a better post-operative analgesia for knee and below knee surgeries [4]. This block is an easily administrable nerve block to achieve analgesia of the sciatic nerve distribution in supine position for knee surgeries postoperatively [5]. 

The main advantages we have observed in our practice are easy to perform in supine position (even without frog leg position), no need for separate injection or position change to block the sciatic nerve, relatively safer in experienced hand, good choice for post-op analgesia in below knee surgeries, predominantly sensory blockade in the distribution of sciatic nerve.

We hypothesised that 0.125% bupivacaine with two different doses of dexmedetomidine 0.5 µg/kg and 1 µg/kg may have different satisfactory level when administered in ultrasound guided 4-in-1 block. Since this block is a relatively new block and only a couple of studies are available in literature, it would be worthwhile to compare the Patients’ satisfaction scores in 4-in-1 block with bupivacaine in combination with dexmedetomidine in two doses.

Aim and Objectives

To compare the Patients’ satisfaction scores postoperatively in ultrasound guided 4- in -1 nerve block with Bupivacaine in Combination with Dexmedetomidine in Two Doses for knee and below knee orthopaedic surgeries.

Study Area

Department of Anaesthesiology, Dr. R.P.G.M.C. Kangra at Tanda, Himachal Pradesh.

Study Population

All consecutive patients in the age group 18-60 years including both genders scheduled for knee and below knee surgery under Subarachnoid Block (SAB) were enrolled for this study after obtaining written informed consent.

Study Duration

After approval by Institutional Ethics Committee (IEC), this prospective, randomized, double blinded, study was carried out over a period of 18 months including data collection, data organization, presentation, data analysis and data interpretation.

Sample Size

All patients within this duration and fulfilling our inclusion criteria were included in the study. The patients were divided into two groups -group A and group B. For each group, 50 patients were evaluated after randomization.

Inclusion Criteria

• ASA grade Ⅰ and Ⅱ patients scheduled for knee and below knee surgery under SAB with expected duration of 2 hours were intended in the current study

• BMI 18.5-29.9 Kg/m²

Exclusion Criteria

• Patient’s refusal for spinal anaesthesia or 4- in -1 block

• Patients with anatomical deformities

• Patients with coagulopathies and bleeding disorders

• Patients with hypersensitivity to study drugs

• Patients on anticoagulants

• Local infection at the site where needle for block is to be inserted

• Patients with known bradyarrhythmia, heart block significant cognitive impairment

• Failure of spinal anaesthesia

Study Design

It was a prospective, randomized, double-blindstudy. The patients undergoing knee and below knee surgery were randomly divided into two groups (A and B). Randomization was achieved by computer-generated random number table. The randomization group assigned was enclosed in a sealed opaque envelope to ensure concealment of allocation sequence. After shifting the patient inside operation theatre, sealed envelope was opened by anaesthesiologist not involved in the study to prepare the drug solution according to allocation. The drug solution made was then made and handed over to the team member giving the block.

Methodology

The study commenced after obtaining institutional scientific review and protocol committee, ethics committee approval and written informed patient’s consent.

The enrolled patients, after fulfilling all the inclusion and exclusion criteria, were divided into 2 groups:

• Group A: Received 29 ml of 0.125% bupivacaine with 0.5 µg/kg dose of dexmedetomidine (1 mL) making it to a total 30 mL solution, in USG guided 4-in-1 block

• Group B: Received 29 mL of 0.125% bupivacaine with 1 µg/kg dose of dexmedetomidine (1 mL) making it to a total 30 ml solution, in USG guided 4-in-1 block

Anaesthetic Procedure

Pre-anaesthetic assessment was done one day prior to surgery. All patients were explained about the procedure, advantages and risks of the procedure. The patients were educated about the 11-point Verbal Rating Scale (VRS) where 0 is no pain and 10 is worst imaginable pain. Thereafter written consent was taken and clinical details were recorded in a predesigned proforma.

All the patients were kept nil orally for 8 hours before surgery and pre-medicated with tablet alprazolam 0.25 mg and tablet ranitidine 150 mg the night before surgery and 2 hours before surgery with a sip of water. In the operation theatre, an 18-gauge Intravenous (IV) cannula was secured followed by 0.9% sodium chloride (Normal Saline [NS]) infusion. After establishing standard anaesthesia monitoring, baseline parameters such as Heart Rate (HR), non-invasive blood pressure and peripheral oxygen saturation were recorded. Patients were given SAB after cleaning and draping, in sitting position using 26-gauge Quincke spinal needle at L3–L4 interspace with 3.0ml 0.5% hyperbaric bupivacaine after ensuring free flow of cerebrospinal fluid. After confirmation of adequate level (T6) the surgeon was allowed to proceed with the surgery. All patients were monitored intraoperatively for systolic, diastolic, mean blood pressure, heart rate and oxygen saturation. Any hypotension episode (defined as a reduction in mean arterial blood pressure> 30% of baseline) was treated with injection ephedrine 6 mg bolus and episodes of bradycardia (HR <50 beats/min) was treated with injection atropine 0.02 mg/kg. After completion of surgery, the patients were shifted to PACU and monitored for the regression of sensory block to T₁₀ level, following which they were given the ultrasound guided 4- in -1 nerve block.

Procedure of the Block

The patient was positioned in supine position with the ipsilateral leg kept in external rotation, slight abduction and knees slightly flexed (frog leg position). The medial femoral condyle was marked.

A linear high frequency ultrasound probe, ultrasoundSonositeMicromaxx® (Sonosite®, Bothell, WA, USA) was used. After skin disinfection with povidone iodine, sterile drapes were applied. The linear probe (8–12 Hz) covered with sterile plastic sheath and with sufficient application of sterilised gel was placed over the femoral condyle and vastus medialis muscle identified and scanned proximally. The vastus and sartorius intersection (antero-medial intermuscular septum) were identified and the probe was taken proximal till the superficial femoral artery appears in the adductor hiatus. The probe was then slid slowly proximally till the descending genicularartery branching from superficial femoral artery is visualized in the hiatus. This point was the injection point which is 8-10 cm above the femoral condyle. Under all aseptic precautions, a22-gaugeechogenic needle was used by an ultrasound-guided in-plane from lateral to medial side under to reach perivascular region and after negative aspiration, the test drug was injected to spread around the femoral artery and also in a plane to push the Sartorius muscle up and hence blocking four nerves namely saphenous, obturator, sciatic and nerve to vastus medialis.

Subsequently, each patient was observed for pain, vitals and side effects at hourly intervals as mentioned in the proforma (i.e., 0, 1, 2, 4, 6, 12, 18 and 24 hours) for 24 hours by an anaesthesiologist blinded to group assignment. For the first 24 hours, the protocol for postoperative analgesia consisted of standard orders for injection i.v paracetamol 1gm i.v for VAS > 4 followed by injection i.v. diclofenacaqueous solution 1.5 mg/kg if pain not relieved with the former. For breakthrough pain, patients were treated with injection i.v. tramadol 0.5 mg/kg as and when required. The patients were evaluated for the Patient Satisfaction.

Patients were asked to rate on a 3-point scale their satisfaction with pain management:

• Very satisfied

• Satisfied

• Not satisfied

Statistical Analysis

The data were recorded into Microsoft® Excel workbook 2019 and exported into SPSS v21.0 (IBM, USA) for statistical analysis. Categorical variables were expressed as frequency, percentage and compared using Chi square test. Quantitative variables were expressed as mean, standard deviation and compared using Student t-test. P value <0.05 was considered significant.

The present study was aimed to compare the Patients’ satisfaction scores in ultrasound guided 4- in -1 nerve block with Bupivacaine in Combination with Dexmedetomidine in Two Doses for knee and below knee orthopaedic surgeries. After Institutional Ethics Committee approval and written informed consent, one hundred and eight patients of ASA I and II category, aged between 18–60 years, were recruited in the study. Eight patients, however, were excluded from the study as per the exclusion criteria. Fifty patients in each group completed the study successfully. A total of 100 patients were randomly divided into 2 groups. The groups made have been elaborated as following:

• Group A: About 29 mL of 0.125% bupivacaine with 0.5µg/kg dose of dexmedetomidine (1 mL) making it to a total 30 mL solution, in USG guided 4 in 1 block

• Group B: About 29 mL of 0.125% bupivacaine with 1µg/kg dose of dexmedetomidine (1mL) making it to a total 30 mL solution, in USG guided 4 in 1 block

In this study, mean age of the participant was 40.64±11.44 years in Group A and 40.12±12.55 years in Group B ranging from 18 years to 60 years. Maximum participant in Group A (n = 18) aged between 41 and 50 years and in Group B (n =17) were aged between 30 and 40 years. Only 10 participants aged below 30 in both the groups. The study population comprised of 36 males in Group A and 31 males in Group B and 14 females in Group A and 19 females in Group B. There was no significant difference of gender between both groups (p = 0.287) (Table 1).

In this study, we compared three anthropometric characteristics namely height, weight and BMI. The mean weight in group A was 65.12±8.59kg and in group B was 64.14±8.72 kg (p = 0.573). The mean height in group A was 167.95±7.53cm and in group B was 165.71±7.49 cm (p = 0.139). The mean BMI in group A was 28.21±3.25kg/m² and in group B was 27.62±3.75 kg/m² (p = 0.408). There was no significant difference between both groups in terms of weight, height and BMI (Table 1).

Table 1: Distribution of Participants According to Socio-Demographic Variables

In this study, there was no significant comparison between both the groups according to ASA grade. Distribution of patients in ASA grade 1 is non-significant in group A as compared to Group B (p = 0.827). In this study, mean duration of surgery in group A and group B was 84.70±30.60 min and 91.60±31.90 min respectively. There was no significant difference of duration of surgery between both groups (p = 0.272) (Table 2).

Table 2: Distribution of Participants According to ASA Grades and Mean Duration of Surgery 

In this study, 18% of the patients were very satisfied in group B while only 4% were very satisfied in group A. Similarly, 68% of the patients were satisfied in group B while 66% were very satisfied in group A. In this study, only 14% of the patients were not satisfied in group B while 30% were not satisfied in group A. We found that the patients’ satisfaction was significantly better in group B in comparison to group A (p = 0.024) (Table 3).

Table 3: Satisfaction Score

The transition from central neuraxial blocks, such as combined spinal epidural, to regional neuraxial blocks, such as the femoral, sciatic, adductor and combined femoral and sciatic for targeting pain-free TKA, has opened the door to an increasing amount of study on the topic. Since several nerves (genicular nerves) from the femoral, obturator and sciatic nerves supply the knee joint, a thorough yet straightforward method is required for complete analgesia and positive patient satisfaction postoperatively.

In our study, 18% of the patients were very satisfied in group B while only 4% were very satisfied in group A. We found that the patients’ satisfaction was significantly better in group B in comparison to group A (p = 0.024). In the study by Kaur et al, 90 patients in the age group of 18-55 years, divided randomly into two groups: Group A received 40 ml of solution containing 30 ml 0.5% levobupivacaine and 10 ml 1% lignocaine and group B received 40 ml of solution containing 30 ml 0.25% levobupivacaine and 10 mL 1% lignocaine with dexmedetomidine 1 microg/kg for supraclavicular brachial plexus block [6]. Patients’ satisfaction was comparable in their study (p = 0.814).

With the 4-in-block technique, we could not find much literature regarding patient’s satisfaction. As the technique is new and would require further studies.

In the present study, patients’ satisfaction was significantly better in group B in comparison to group A. Hence, it was concluded that the use of1µg/kg dexmedetomidine as an adjunct to 0.125% bupivacaine in USG guided 4- in -1 nerve block increase patients’ satisfaction in comparison to 0.5µg/kg dexmedetomidine.

Ethical Approval

The study was approved by IEC (HFW-H/DRPGMC/Ethics/2019/221; dated 21/12/2019) at Dr RPGMC Kangra at Tanda. All the patients were included after they agreed to give their consent.

1. Reuben, S.S. and J. Sklar. “Pain management in patients who undergo outpatient arthroscopic surgery of the knee.” The Journal of Bone and Joint Surgery. American Volume, vol. 82, 2000, pp. 1754–1766.

2. Castillo, R.C. et al. “Prevalence of chronic pain seven years following limb-threatening lower extremity trauma.” Pain, vol. 124, 2006, pp. 321–329.

3. Rodgers, A. et al. “Reduction of postoperative mortality and morbidity with epidural or spinal anaesthesia: Results from overview of randomised trials.” BMJ, vol. 321, 2000, p. 1493.

4. Roy, R. et al. “Ultrasound guided 4 in 1 block-a newer, single injection technique for complete postoperative analgesia for knee and below knee surgeries.” Anaesthesia, Pain and Intensive Care, 2018, pp. 87–92.

5. Srinivasan, P. et al. “Ultrasound guided 4 in 1 block for managing postoperative pain in arthroscopic knee surgery.” Sri Lankan Journal of Anaesthesiology, vol. 27, 2019, pp. 86–88.

6. Kaur, H. et al. “Effect of dexmedetomidine as an adjuvant to levobupivacaine in supraclavicular brachial plexus block: A randomized double-blind prospective study.” Journal of Anaesthesiology Clinical Pharmacology, vol. 31, 2015, pp. 333–338.