Evaluation of the effect of intraoperative tropisetron on postoperative rebound pain after brachial plexus block: a randomized controlled trial

Introduction

Postoperative rebound pain after peripheral nerve block increases patient suffering and delays recovery after surgery.

Objectives

We tested whether the 5HT-3 receptor antagonist and α7nAChR agonist tropisetron could prevent postoperative rebound pain.

Methods

A total of 115 patients were randomized to receive 5-mg/5-mL tropisetron or the same volume of normal saline. Pain intensity was measured with the numerical rating scale of pain (NRS). Rebound pain was defined as a change from mild pain (NRS ≤ 3) measured in the postanesthesia care unit to severe pain (NRS ≥ 7) within 24 hours after peripheral nerve blockade. Logistic regression was used to identify relevant factors associated with postoperative rebound pain.

Results

Tropisetron did not affect the NRS score or the incidence of rebound pain after peripheral nerve block. Logistic regression revealed that preoperative pain, bone surgery, and length of incision were risk factors for postoperative rebound pain, and patient-controlled analgesia was protective against postoperative rebound pain.

Conclusion

Tropisetron does not affect the incidence of rebound pain after peripheral nerve block. Patients at high risk of postoperative rebound pain should be identified for appropriate management. Registration site: www.chictr.org.cn (ChiCTR2300069994).

Regional Anesthesia Complications and Contraindications

Regional anesthesia has a strong role in minimizing post-operative pain, decreasing narcotic use and PONV, and, therefore, speeding discharge times. However, as with any procedure, regional anesthesia has both benefits and risks. It is important to identify the complications and contraindications related to regional anesthesia, which patient populations are at highest risk, and how to mitigate those risks to the greatest extent possible. Overall, significant complications secondary to regional anesthesia remain low. While a variety of different regional anesthesia techniques exist, complications tend to fall within 4 broad categories: block failure, bleeding/hematoma, neurological injury, and local anesthetic toxicity.

The effects of dexamethasone added to ilioinguinal/iliohypogastric nerve (IIN/IHN) block on rebound pain in inguinal hernia surgery: a randomized controlled trial

PURPOSE

The purpose of the present study was to evaluate the effects of IV dexamethasone added to one single injection Ilioinguinal/Iliohypogastric Nerve (IIN/IHN) block on tramadol consumption and Modified Rebound Pain Score (MRPS) in the first postoperative 24 h in inguinal hernia surgery.

METHODS

Five mg IV dexamethasone as an analgesic adjunct in the multimodal analgesia was administered to the patients who were scheduled for Inguinal Hernia Surgery and randomized to Group Dex and normal saline was administered to the patients who were randomized to the Control Group in addition to IIN/IHN Block. Postoperative tramadol consumption, Modified Rebound Pain Score (MRPS), the incidence of Rebound Pain, Rebound Pain time, postoperative 48-h opioid consumption, Numerical Rating Scale (NRS) scores, Quality of Recovery Score (QoR-15), Sleep Quality, and adverse events were evaluated in the patients.

RESULTS

The mean scores of MRPS were lower in Group Dex than in the Control Group, both at rest (p = 0.001) and with motion (p = 0.001). Tramadol consumption in the first postoperative 24 h was 45.17 ± 49.59 mg in Group Dex and 95 ± 59.23 mg in the Control Group. The difference between the groups was statistically significant (p < 0.001).

CONCLUSIONS

In conclusion, adding IV dexamethasone as a part of multimodal analgesia to IIN/IHN block for inguinal hernia surgery resulted in lower MRPS and lower postoperative opioid (tramadol) consumption. For this reason, IV dexamethasone can be added to the IIN/IHN block after inguinal hernia surgery to reduce the incidence of rebound pain, rebound pain scores, and NRS scores for pain, decrease postoperative opioid consumption, and improve the quality of recovery.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov: Ref; NCT05172908, Date: December 29, 2021.

Postoperative Rebound Pain: Our Current Understanding About the Role of Regional Anesthesia and Multimodal Approaches in Prevention and Treatment

PURPOSE OF REVIEW

Rebound pain (RP) is a common occurrence after peripheral nerve block placement, especially when blocks are used for orthopedic surgery. This literature review focuses on the incidence and risk factors for RP as well as preventative and treatment strategies.

RECENT FINDINGS

The addition of adjuvants to a block, when appropriate, and starting patients on oral analgesics prior to sensory resolution are reasonable approaches. Using continuous nerve block techniques can provide extended analgesia through the immediate postoperative phase when pain is the most intense. Peripheral nerve blocks (PNBs) are associated with RP, a frequent phenomenon that must be recognized and addressed to prevent short-term pain and patient dissatisfaction, as well as long-term complications and avoidable hospital resource utilization. Knowledge about the advantages and limitations of PNBs allows the anesthesiologists to anticipate, intervene, and hopefully mitigate or avoid the phenomenon of RP.

Magnitude and severity of rebound pain after resolution of peripheral nerve block and associated factors among patients undergoes surgery at university of gondar comprehensive specialized hospital northwest, Ethiopia, 2022. Longitudinal cross-sectional study

Background

Rebound pain is extreme pain that persists after the effects of regional anesthesia wear off. Rebound pain occurrence and intensity are influenced by patient, surgical, and anesthesia-related factors. The incidence and severity of rebound pain after peripheral nerve block resolution are both reduced by the use of perioperative multimodal strategy. The purpose of the current paper was to evaluate the frequency, seriousness, and risk factors for rebound pain following peripheral nerve block resolution.

Method

A cross-sectional study centred on 384 patients who had received peripheral nerve blocks was carried out from August 20, 2021, to June 30, 2022. A semi-structured questionnaire was used to gather information within 24 h following the block's performance. SPSS 25 was used to enter and analyze the data. The change from well-controlled pain while the block is operating to severe pain within 24 h of block performance is known as rebound pain. Both univariate and multivariable analyses were used to examine the relationship between various parameters (patient, surgical, and anesthetic-related factors) and rebound pain. In the multivariable analysis, a P-value of 0.05 or lower is regarded as statistically significant.

Results

The incidence of rebound pain after peripheral nerve block was resolved was 61.7% (95% CI: 56.5-66.7) with a mean rebound pain score of 4.19 ± 2. Of the total 237, 120(50.6%) had severe rebound pain after the peripheral nerve block was resolved. The use of preoperative intravenous dexamethasone (AOR: 2.6, 95%CI: 20.29-24.57), preoperative pain (AOR: 3.9, 95%CI: 41-57.4), type of surgery (AOR: 6.5, 95%CI: 1.45-11.7), post-operative NSAID (AOR: 2.2, 95%CI: 17.69-20.8), and opioid use (AOR: 2.2, 95%CI: 19.1-22.56) were independent risks associated with rebound pain.

Conclusions

and Recommendation: Rebound pain occurred in 61.7% of patients and had independent associations with preoperative pain, dexamethasone premedication, type of surgery, use of an adjuvant, use of postoperative opioids, and NSAIDs. Therefore, clinicians should continue to use preventative strategies, especially for patients at higher risk of experiencing rebound pain.

Rebound Pain After Peripheral Nerve Blockade-Bad Timing or Rude Awakening?

Patients who have perioperatively benefited from regional anesthesia frequently report moderate to severe pain when the nerve block effects fade away. Over the past years, the term "rebound pain" has been introduced, suggesting a specific pathologic process. It is debated whether significant pain on block resolution reflects a separate and distinct pathologic mechanism potentially involving proinflammatory and neurotoxic effects of local anesthetics, or is simply caused by the recovery of sensory function at a timepoint when nociceptive stimuli are still intense, and moderate to severe pain should be anticipated. In that latter case, the phenomenon referred to as rebound pain could be considered a failure of pain management providers to devise an adequate analgesia plan. Whatever the ultimate designation, management of rebound pain should be proactive, by implementing multimodal analgesia, or tailoring the blockade to the expected trajectory of postoperative pain and managing patient expectations accordingly. Until we know more about the etiology and impact of this phenomenon, the authors suggest a more neutral designation such as "pain on block resolution."

Effect of remifentanil on post-operative analgesic consumption in patients undergoing shoulder arthroplasty after interscalene brachial plexus block: a randomized controlled trial

PURPOSE

Remifentanil is useful in balanced anesthesia; however, there is concern regarding opioid-induced hyperalgesia. The effect of remifentanil on rebound pain, characterized by hyperalgesia after peripheral nerve block has rarely been studied. This study evaluated whether intraoperative remifentanil infusion may increase postoperative analgesic requirement in patients receiving preoperative interscalene brachial plexus block (IBP).

METHODS

Sixty-eight patients undergoing arthroscopic shoulder surgery under general anesthesia were randomly allocated to remifentanil (R) or control (C) group. Preoperative IBP with 0.5% ropivacaine 15 mL was performed in all patients. Intraoperative remifentanil was administered only in the R group. Postoperative pain was controlled using intravenous patient-controlled analgesia (IV-PCA) and rescue analgesics. The primary outcome was the dosage of fentanyl-nefopam IV-PCA infused over 24 h postoperatively. The secondary outcomes included the numeric rating scale (NRS) score recorded at 4-h intervals over 24 h, amount of rescue analgesics and total postoperative analgesics used over 24 h, occurrence of intraoperative hypotension, postoperative nausea and vomiting (PONV) and delirium.

RESULTS

The dosage of fentanyl-nefopam IV-PCA was significantly less in C group than R group for postoperative 24 h. Fentanyl 101 [63-158] (median [interquartile range]) µg was used in the C group, while fentanyl 161 [103-285] µg was used in the R group (median difference 64 µg, 95% CI 10-121 µg, P = 0.02). Nefopam 8.1 [5.0-12.6] mg was used in the C group, while nefopam 12.9 [8.2-22.8] mg was used in the R group (median difference 5.1 mg, 95% CI 0.8-9.7 mg, P = 0.02). The total analgesic consumption: the sum of PCA consumption and administered rescue analgesic dose, converted to morphine milligram equivalents, was higher in the R group than C group (median difference 10.9 mg, 95% CI 3.0-19.0 mg, P = 0.01). The average NRS score, the incidence of PONV and delirium, were similar in both groups. The incidence of intraoperative hypotension was higher in R group than C group (47.1% vs. 20.6%, P = 0.005).

CONCLUSIONS

Remifentanil administration during arthroscopic shoulder surgery in patients undergoing preoperative IBP increased postoperative analgesic consumption.

Regional Anesthesia Complications and Contraindications

Regional anesthesia has a strong role in minimizing post-operative pain, decreasing narcotic use and PONV, and, therefore, speeding discharge times. However, as with any procedure, regional anesthesia has both benefits and risks. It is important to identify the complications and contraindications related to regional anesthesia, which patient populations are at highest risk, and how to mitigate those risks to the greatest extent possible. Overall, significant complications secondary to regional anesthesia remain low. While a variety of different regional anesthesia techniques exist, complications tend to fall within 4 broad categories: block failure, bleeding/hematoma, neurological injury, and local anesthetic toxicity.

Supraclavicular block with Mepivacaine vs Ropivacaine, their impact on postoperative pain: a prospective randomised study

BACKGROUND

Supraclavicular block (SCB) with long-acting local anaesthetic is commonly used for surgical repair of distal radial fractures (DRF). Studies have shown a risk for rebound pain when the block fades. This randomised single-centre study aimed to compare pain and opioid consumption the first three days post-surgery between SCB-mepivacaine vs. SCB-ropivacaine, with general anaesthesia (GA) as control.

METHODS

Patients (n = 90) with ASA physical status 1-3 were prospectively randomised to receive; SCB with mepivacine 1%, 25-30 ml (n = 30), SCB with ropivacaine 0.5%, 25-30 ml (n = 30) or GA (n = 30) with propofol/fentanyl/sevoflurane. Study objectives compared postoperative pain with Numeric Rating Scale (NRS) and sum postoperative Opioid Equivalent Consumption (OEC) during the first 3 days post-surgery between study-groups.

RESULTS

The three groups showed significant differences in postoperative pain-profile. Mean NRS at 24 h was significantly lower for the SCB-mepivacaine group (p = 0.018). Further both median NRS and median OEC day 0 to 3 were significanly lower in the SCB-mepivacaine group as compared to the SCB-ropivacaine group during the first three days after surgery; pain NRS 1 (IQR 0.3-3.3) and 2.7 (IQR 1.3-4.2) (p = 0.017) and OEC 30 mg (IQR 10-80) and 85 mg (IQR 45-125) (p = 0.004), respectively. The GA-group was in between both in pain NRS and median sum OEC. Unplanned healthcare contacts were highest among SCB-ropivacaine patients (39.3%) vs. SCB-mepivacaine patients (0%) and GA-patients (3.4%).

CONCLUSIONS

The potential benefit of longer duration of analgesia, associated to a long-acting local anaesthetic agent, during the early postoperative course must be put in perspective of potential worse pain progression following block resolution.

TRIAL REGISTRATION

NCT03749174 (clinicaltrials.gov, Nov 21, 2018, retrospectively registered).

Pain after upper limb surgery under peripheral nerve block is associated with gut microbiome composition and diversity

Gut microbiota play a role in certain pain states. Hence, these microbiota also influence somatic pain. We aimed to determine if there was an association between gut microbiota (composition and diversity) and postoperative pain. Patients (n = 20) undergoing surgical fixation of distal radius fracture under axillary brachial plexus block were studied. Gut microbiota diversity and abundance were analysed for association with: (i) a verbal pain rating scale of < 4/10 throughout the first 24 h after surgery (ii) a level of pain deemed "acceptable" by the patient during the first 24 h following surgery (iii) a maximum self-reported pain score during the first 24 h postoperatively and (iv) analgesic consumption during the first postoperative week. Analgesic consumption was inversely correlated with the Shannon index of alpha diversity. There were also significant differences, at the genus level (including Lachnospira), with respect to pain being "not acceptable" at 24 h postoperatively. Porphyromonas was more abundant in the group reporting an acceptable pain level at 24 h. An inverse correlation was noted between abundance of Collinsella and maximum self-reported pain score with movement. We have demonstrated for the first time that postoperative pain is associated with gut microbiota composition and diversity. Further work on the relationship between the gut microbiome and somatic pain may offer new therapeutic targets.

Is supplemental regional anesthesia associated with more complications and readmissions after ankle fracture surgery in the inpatient and outpatient setting?

BACKGROUND

There is concern that regional anesthesia is associated with increased risk of complications, including return to the hospital for uncontrolled pain once the regional anesthetic wears off.

METHODS

Retrospective database review of patients who underwent open reduction and internal fixation of a closed ankle fracture from 2014-16 who received general anesthesia alone (GA) or general anesthesia plus regional anesthesia (RA).

RESULTS

9459 patients met inclusion criteria. Patients in the RA group had significantly longer operative duration in both inpatient (GAI=71min vs RAI=79min, p=0.002) and outpatient setting (GAO=66min vs RAI=72min, p<0.001), lower overall LOS (GA=1.7 days vs RA=1.1 days, p<0.001), and higher readmission rate for pain (RAO=4 [0.3%] vs GAO=1 [0.0%], p=0.007).

CONCLUSIONS

Patients who received supplemental regional anesthesia had shorter hospital LOS, increased operative time, and increased readmission rates for rebound pain. However, the small number of patients needing readmission are not clinically significant demonstrating that regional anesthesia is safe, effective and readmission for rebound pain should not be a concern.

LEVEL OF EVIDENCE

III.

The effect of perineural dexamethasone on rebound pain after ropivacaine single-injection nerve block: a randomized controlled trial

BACKGROUND

Rebound pain after a single-shot nerve block challenges the real benefit of this technique. We aimed to investigate whether perineural dexamethasone addition decreased the incidence of rebound pain after a single-shot nerve block.

METHODS

We randomly allocated 132 patients scheduled for open reduction internal fixation of an upper extremity closed fracture under single-shot peripheral nerve block and sedation into two groups. Patients in the dexamethasone group received nerve block with 0.375% ropivacaine and 8 mg dexamethasone, while those in the control group received ropivacaine only. Sixty-three patients in the dexamethasone group and 60 patients in the control group were analyzed for the incidence of rebound pain 48 h after block administration, which was the primary outcome. The secondary outcomes included the highest self-reported numeric rating scale (NRS) pain score, and NRS at 8, 12, 24, and 48 h after the block, sufentanil consumption, sleep quality on the night of surgery, patient satisfaction with the pain therapy, blood glucose at 6 h after the block, pain and paresthesia at 30 days after surgery.

RESULTS

The incidence of rebound pain was significantly lower in the dexamethasone group (7 [11.1%] of 63 patients) than in the control group (28 [48.8%] of 60 patients [RR = 0.238, 95% CI (0.113-0.504), p = 0.001]. Dexamethasone decreased opioid consumption in 24 h after surgery (p < 0.001) and improved the sleep quality score on the night of surgery (p = 0.01) and satisfaction with pain therapy (p = 0.001). Multivariate logistic regression analysis showed that only group allocation was associated with the occurrence of rebound pain [OR = 0.062, 95% CI (0.015-0.256)]. Patients in the dexamethasone group reported later onset pain (19.7 ± 6.6 h vs 14.7 ± 4.8 h since block administration, mean ± SD, p < 0.001) and lower peak NRS scores [5 (3, 6) vs 8 (5, 9), median (IQR), p < 0.001] than those in the control group.

CONCLUSIONS

The perineural administration of 8 mg dexamethasone reduces rebound pain after a single-shot nerve block in patients receiving ORIF for an upper limb fracture.

TRIAL REGISTRATION

This study was retrospectively registered in the Chinese Clinical Trial Registry ( ChiCTR-IPR-17011365 ) on May 11th, 2017.

Dexmedetomidine combined with suprascapular nerve block and axillary nerve block has a synergistic effect on relieving postoperative pain after arthroscopic rotator cuff repair

PURPOSE

Suprascapular nerve block (SSNB) is the most commonly used block for the relief of postoperative pain from arthroscopic rotator cuff repair and can be used in combination with axillary nerve block (ANB). Dexmedetomidine (DEX) is a type of alpha agonist that can elongate the duration of regional block. The aim of this study was to compare the effects of the use of dexmedetomidine combined with SSNB and ANB with those of the use of SSNB and ANB alone on postoperative pain, satisfaction, and pain-related cytokines within the first 48 h after arthroscopic rotator cuff repair.

METHODS

Forty patients with rotator cuff tears who had undergone arthroscopic rotator cuff repair were enrolled in this single-center, double-blinded randomized controlled trial study. Twenty patients were randomly allocated to group 1 and received ultrasound-guided SSNB and ANB using a mixture of 0.5 ml (50 μg) of DEX and 9.5 ml of 0.75% ropivacaine preemptively. The other 20 patients were allocated to group 2 and underwent ultrasound-guided SSNB and ANB alone using a mixture of 0.5 ml of normal saline and 9.5 ml of ropivacaine. The visual analog scale (VAS) for pain and patient satisfaction (SAT) scores were postoperatively checked within 48 h. The plasma interleukin (IL)-6, IL-8, IL-1β, cortisol, and serotonin levels were also postoperatively measured within 48 h.

RESULTS

Group 1 showed a significantly lower mean VAS (visual analog scale of pain) score 1, 3, 6, 12, 18 and 24 h after operation, and a significantly higher mean SAT (patient satisfaction) score 1, 3, 6, 12, 18, 24 and 36 h after the operation than group 2. Group 1 showed a significantly lower mean plasma IL-8 level 1 and 48 h after the operation, and a significantly lower mean IL-1β level 48 h after the operation than group 2. Group 1 showed a significantly lower mean plasma serotonin level 12 h after the operation than group 2. The mean timing of rebound pain in group 1 was significantly later than that in group 2 (36 h > 23 h, p = 0.007). Six patients each in groups 1 and 2 showed rebound pain. The others did not show rebound pain.

CONCLUSIONS

Ultrasound-guided SSNA and ANB with DEX during arthroscopic rotator cuff repair resulted in a significantly lower mean VAS score and a significantly higher mean SAT score within 48 h after the operation than SSNB and ANB alone. Additionally, SSNB and ANB with DEX tended to result in a later mean timing of rebound pain accompanied by significant changes in IL-8, IL-1β, and serotonin levels within 48 h after the operation. The present study could provide the basis for selecting objective parameters of postoperative pain in deciding the optimal use of medication for relieving pain.

LEVEL OF EVIDENCE

Level I.

TRIAL REGISTRATION

2015-20, ClinicalTrials.gov Identifier: NCT04398589.

IRB NUMBER

2015-20, Hallym University Chuncheon Sacred Heart Hospital.

Managing rebound pain after regional anesthesia

Rebound pain after regional anesthesia can be defined as transient acute postoperative pain that ensues following resolution of sensory blockade, and is clinically significant, either with regard to the intensity of pain or the impact on psychological well-being, quality of recovery, and activities of daily living. Current evidence suggests that it represents an unmasking of the expected nociceptive response in the absence of adequate systemic analgesia, rather than an exaggerated hyperalgesic phenomenon induced by local anesthetic neural blockade. In the majority of patients, it does not appear to significantly impact cumulative postoperative opioid consumption, quality of recovery, or patient satisfaction, and is not associated with longer-term sequelae such as persistent post-surgical pain. Nevertheless, it must be considered whenever regional anesthesia is incorporated into perioperative management. Strategies to mitigate the impact of rebound pain include routine prescribing of a systemic multimodal analgesic regimen, as well as patient education on appropriate expectations regarding block offset and expected surgical pain, and timely initiation of analgesic medication. Prolonging the duration of action of regional anesthesia with continuous catheter techniques or local anesthetic adjuncts may also help alleviate rebound pain, although further research is required to confirm this.

Dexmedetomidine combined with interscalene brachial plexus block has a synergistic effect on relieving postoperative pain after arthroscopic rotator cuff repair

PURPOSE

Interscalene brachial plexus block (ISB) is one of the most commonly used regional blocks in relieving postoperative pain after arthroscopic rotator cuff repair. Dexmedetomidine (DEX) is an alpha 2 agonist that can enhance the effect of regional blocks. The aim of this study was to compare the effects of DEX combined with ISB with ISB alone on postoperative pain, satisfaction, and pain-related cytokines within the first 48 h after arthroscopic rotator cuff repair.

METHODS

Fifty patients with rotator cuff tears who had undergone arthroscopic rotator cuff repair were enrolled in this single center, double-blinded randomized controlled trial study. Twenty-five patients were randomly allocated to group 1 and received ultrasound-guided ISB using a mixture of 1 ml (100 μg) of DEX and 8 ml of 0.75% ropivacaine preemptively. The other 25 patients were allocated to group 2 and underwent ultrasound-guided ISB alone using a mixture of 1 ml of normal saline and 8 ml of ropivacaine. The visual analog scale (VAS) for pain and patient satisfaction (SAT) scores were checked within 48 h postoperatively. The plasma interleukin (IL)-6, -8, -1β, cortisol, and substance P levels were also measured within 48 h, postoperatively.

RESULTS

Group 1 showed a significantly lower mean VAS score and a significantly higher mean SAT score than group 2 at 1, 3, 6, 12, and 18 h postoperatively. Compared with group 2, group 1 showed a significantly lower mean plasma IL-6 level at 1, 6, 12, and 48 h postoperatively and a significantly lower mean IL-8 level at 1, 6, 12, 24, and 48 h postoperatively. The mean timing of rebound pain in group 1 was significantly later than that in group 2 (12.7 h > 9.4 h, p = 0.006).

CONCLUSIONS

Ultrasound-guided ISB with DEX in arthroscopic rotator cuff repair led to a significantly lower mean VAS score and a significantly higher mean SAT score within 48 h postoperatively than ISB alone. In addition, ISB with DEX showed lower mean plasma IL-6 and IL-8 levels than ISB alone within 48 h postoperatively, with delayed rebound pain.

LEVEL OF EVIDENCE

I.

TRIAL REGISTRATION

2013-112, ClinicalTrials.gov Identifier: NCT02766556.

Prolonged pain reducing effect of sodium hyaluronate-carboxymethyl cellulose solution in the selective nerve root block (SNRB) of lumbar radiculopathy: a prospective, double-blind, randomized controlled clinical trial

BACKGROUND

The pattern of linear graph schematized by visual analogue scale (VAS) score displaying pain worsening between 2 days and 2 weeks after selective nerve root block (SNRB) is called rebound pain.

PURPOSE

The purpose of this study was to determine if sodium hyaluronate and carboxymethyl cellulose solution (HA-CMC sol) injection could reduce the occurrence of rebound pain at 3 days to 2 weeks after SNRB in patients with radiculopathy compared with injection with corticosteroids and local anesthetics alone.

STUDY DESIGN/SETTING

Double blinded randomized controlled clinical trial.

PATIENT SAMPLE

A total of 44 patients (23 of 24 patients in the Guardix group and 21 of 24 patients in the control group) who finished the follow-up session were subjects of this study.

OUTCOME MEASUREMENT

Patients were asked to write down their average VAS pain scores daily for 12 weeks. Functional outcomes were assessed by Oswestry Disability Index, Roland Morris Disability Questionnaire , and Short Form-36.

METHOD

A cocktail of corticosteroids, 1% lidocaine, 0.5% Bupivacaine, and 1 mL of normal saline was used for the control group whereas a cocktail of corticosteroids, 1% lidocaine, 0.5% Bupivacaine, and 1 mL of HA-CMC solution was used for the G group. Study participants were randomized into one of two treatment regimens. They were followed up for 3 months.

RESULTS

VAS score at 2 weeks after the procedure was 4.19±1.32 in the control group, which was significantly (p<.05) higher than that (2.43±1.24) in the G group. VAS score at 6 weeks after the procedure was 4.00±1.23 in the control group and 3.22±1.45 in the G group, showing no significant (p=.077) difference between the two groups. There were no significant differences in functional outcomes at 6 or 12 weeks after the procedure.

CONCLUSIONS

Compared with conventional cocktail used for SNRB, addition of HA-CMC sol showed effective control of rebound pain at 3 days to 2 weeks after the procedure.