Suprascapular and Interscalene Nerve Block for Shoulder Surgery

Surgeon-Administered Nerve Block During Rotator Cuff Repair Can Promote Recovery with Little or No Post-operative Opioid Use

BACKGROUND

The use of opioid analgesia is common in both the acute and extended post-operative periods after rotator cuff repair. The current opioid crisis has prompted surgeons to seek alternatives that minimize or even eliminate the need for oral opioids after surgery.

QUESTIONS/PURPOSES

We sought to investigate the effects on post-operative opioid use of a surgeon-administered block of the suprascapular and axillary nerves in arthroscopic rotator cuff repair (ARCR), in particular to quantify outpatient opioid consumption and duration.

METHODS

In this prospective observational study, all patients undergoing primary ARCR performed under general anesthesia by a single surgeon were studied over a 15-month period. Of 91 ARCRs performed, 87 patients were enrolled and followed prospectively. At the conclusion of the procedure, the surgeon performed "local-regional" nerve blockade with injections to the sensory branches of the suprascapular nerve and the axillary nerve, as well as local infiltration about the shoulder. Use of medications in the post-anesthesia care unit was left up to the anesthesiologist. Patients were prescribed oral opioids (hydrocodone/acetaminophen 5/325 mg) for analgesia after discharge. The quantity and duration of opioid use and pain scores were recorded for 4 months. Statistical analysis was performed to evaluate factors that could account for greater opioid use.

RESULTS

Total opioid consumption ranged from 0 to 30 opioid tablets (average, 4.2 tablets) over the 4-month period. Post-operatively, 91% of patients took between ten or fewer tablets, and 39% took no opioids. The average duration of opioid use was 2.4 days. No patients were taking opioids at the 4- to 6-week or 4-month follow-up visits, none required refills, and none received prescriptions from outside prescribers. No statistically significant differences were seen in opioids taken or duration of use in regard to tear size, sex, body mass index, surgery location, or procedure time. There was a significant inverse correlation between opioid use and age. In addition, the cost of the surgeon-performed procedure was substantially lower than that associated with pre-operative nerve blockade performed by an anesthesiologist. All patients were satisfied with the post-operative pain management protocol. Average reported post-operative pain scores were low and decreased at each visit.

CONCLUSION

With this local-regional nerve-blocking protocol, opioid use after ARCR was unexpectedly low, and a large proportion of patients recovered without any post-surgical opioids. The correlation seen between opioid use and age may not be clinically significant, given the low use of post-operative opioids overall. These results may be useful in guiding post-operative opioid prescribing after ARCR, as well as in lowering costs associated with ARCR.

Clinical effect of normal saline injectate into interscalene nerve block catheters given within one hour of local anesthetic bolus on analgesia and hemidiaphragmatic paralysis

BACKGROUND

Previous case reports describe the reversal of phrenic nerve blockade from the interscalene nerve block using normal saline injectate washout. This randomized clinical trial aimed to evaluate whether using normal saline injectate to wash out local anesthetic from an interscalene nerve block catheter would restore phrenic nerve and diaphragm function, while preserving analgesia.

METHODS

Institutional review board approval, clinical trial registration and consent were obtained for patients undergoing shoulder surgery with an interscalene nerve block catheter. 16 patients were randomized to receive three 10 mL aliquots of normal saline injectate (intervention group, n=8) or three sham injectates (control group, n=8) via their perineural catheters in the postanesthesia care unit (PACU). Primary outcome measures were the effects on ipsilateral hemidiaphragmatic paralysis, and secondary outcome measures included PACU opioid consumption, pain scores and change in brachial plexus sensory examination and motor function.

RESULTS

There was no significant difference in reversal of hemidiaphragmatic paralysis. However, there was a greater number of patients in the intervention group who ultimately displayed partial, as opposed to full, paralysis of the hemidiaphragm (p=0.03). There was no significant difference in pain scores, PACU opioid requirement, and brachial plexus motor and sensory examinations between the two groups.

CONCLUSIONS

All patients had persistent hemidiaphragmatic paralysis after the intervention, but fewer patients in the intervention group progressed to full paralysis, suggesting that a larger bolus dose of normal saline may be needed to completely reverse hemidiaphragmatic paralysis. Although normal saline injectate in 10mL increments given through the interscalene nerve block catheter had no clinically significant effect on reversing phrenic nerve blockade, it also did not lead to a reduction in analgesia and may be protective in preventing the progression to full hemidiaphragmatic paralysis.

TRAIL REGISTRATION NUMBER

NCT03677778.

Suprascapular Neuropathy around the Shoulder: A Current Concept Review

Suprascapular neuropathy is an uncommon but increasingly recognized cause of shoulder pain and dysfunction due to nerve entrapment. The aim of this review is to summarize some important aspects of this shoulder pathology. An extensive research was performed on PubMed and Clinical Key. The goal was to collect all the anatomical, biomechanical and clinical studies to conduct an extensive overview of the issue. Attention was focused on researching the state of art of the diagnosis and treatment. A total of 59 studies were found suitable and included. This condition is more frequently diagnosed in over-head athletes or patients with massive rotator cuff tears. Diagnosis may be complex, whereas its treatment is safe, and it has a great success rate. Prompt diagnosis is crucial as chronic conditions have worse outcomes compared to acute lesions. Proper instrumental evaluation and imaging are essential. Dynamic compression must initially be treated non-operatively. If there is no improvement, surgical release should be considered. On the other hand, soft tissue lesions may first be treated non-operatively. However, surgical treatment by arthroscopic means is advisable when possible as it represents the gold standard therapy. Other concomitant shoulder lesions must be recognized and treated accordingly.

A Novel Application of Ultrasound-Guided Interscalene Anesthesia for Proximal Humeral Fractures

BACKGROUND

Proximal humeral fractures are commonly encountered in the emergency department (ED). These injuries are often associated with significant pain, with patients often receiving multiple doses of opiate medications while awaiting definitive management. The interscalene nerve block has been efficacious as perioperative analgesia for patients undergoing operative shoulder repair. The utilization of the interscalene nerve block in the ED for proximal humeral fractures is largely unexplored.

DISCUSSION

We report the use of an ultrasound-guided interscalene nerve block in the ED for a patient presenting with significant pain from a proximal humerus fracture. The procedure provided excellent regional anesthesia with no additional need for intravenous or oral opiates during the rest of her ED course. With the significant risks associated with pain medication, particularly opiates, regional anesthesia may be an excellent option for the appropriate patient in the ED.

CONCLUSIONS

As documented in this report, the ultrasound-guided interscalene block, in particular, may be utilized as a means to provide adequate pain control for patients with proximal humerus fractures in the ED.

Is Supraclavicular Block as Good as Interscalene Block for Acute Pain Control Following Shoulder Surgery? A Systematic Review and Meta-analysis

BACKGROUND

Interscalene block (ISB) is the acute pain management technique of choice for shoulder surgery, but its undesirable respiratory side effects have prompted seeking alternatives. Supraclavicular block (SCB) is proposed as an ISB alternative, but evidence of comparative analgesic and respiratory-sparing effects is inconsistent. We compared the analgesic and respiratory effects of SCB and ISB for shoulder surgery.

METHODS

Trials comparing ISB to SCB for shoulder surgery were sought. We decided a priori that SCB would be an acceptable alternative if it were noninferior for (1) postoperative 24-hour cumulative oral morphine equivalent consumption (primary outcome, noninferiority margin Δ = -25 mg) and (2) postoperative pain (secondary outcome, noninferiority margin Δ = 4.0 cm·hour); and superior for (3) postblock respiratory dysfunction (primary outcome). Opioid-related side effects and block-related complications were also evaluated.

RESULTS

Fifteen studies (1065 patients) were analyzed. In single-injection blocks, SCB was noninferior to ISB for 24-hour morphine consumption (mean difference for SCB-ISB, MD [95% confidence interval {CI}] = -3.11 mg [-9.42 to 3.19], Δ = -25 mg); it was also noninferior for 24-hour pain scores (MD = 0.78 cm·hour [0.07-1.49], Δ = 4.0 cm·hour); and decreased the odds of respiratory dysfunction (odds ratio [OR] [95% CI] = 0.08 [0.01-0.68]). Similarly, in continuous blocks, SCB was noninferior to ISB for 24-hour morphine consumption (MD = 0.46 mg [-6.08 to 5.15], Δ = -25 mg), and decreased the odds of respiratory dysfunction (OR = 0.22 [0.08-0.57]). SCB also decreased odds of minor block-related complications (OR = 0.36 [0.20-0.68] and OR = 0.25 [0.15-0.41] for single-injection and continuous blocks, respectively). Consequently, the null joint-hypothesis was rejected, and SCB can be considered an acceptable alternative to ISB.

CONCLUSIONS

For acute pain control following shoulder surgery, high-quality evidence indicates that SCB can be used as an effective ISB alternative. SCB is noninferior for postoperative opioid consumption and acute pain, and it reduces the odds of postblock respiratory dysfunction.

Determining anatomic accuracy of shoulder field injection: triangular injection technique does adequately reach pain transmitters

Background

Controlling pain after shoulder surgery is a critical component of postsurgical care. Several recent studies have described the use of periarticular, local infiltration anesthesia, and field blocks (FBs) with clinical efficacy after shoulder surgery. The anatomic accuracy and safety of these FBs have not been well described. The purpose of this study was to determine the accuracy of a surgeon performed shoulder field injection. We hypothesized that our field injection would adequately reach the pain transmitters responsible for postsurgical shoulder pain.

Methods

A total of 10 cadaveric specimens were used in the study. A mixture of liposomal bupivacaine, normal saline, and methylene blue totaling 60 cc was prepared. After injection, the specimens were left for 4 hours to allow medication diffusion. The dissection of specimens was performed to identify 4 areas: axillary nerve, suprascapular nerve, supraclavicular nerves, and joint capsule. On dissection, accuracy rates were determined for each area.

Results

All 10 cadaveric specimens were injected and dissected to completion. The dissection of the axillary nerve showed methylene blue dye surrounding the nerve in 10 of 10 (100%) specimens, the suprascapular nerve in 9 of 10 (90%), and the supraclavicular nerves in 10 of 10 (100%). Zero of 10 (0%) specimens had any dye penetrate into the glenohumeral joint or capsule.

Conclusion

The accuracy rates of the injection of the mixture into the shoulder specimens suggest potential to reproduce an FB to the tissues that are responsible for postoperative pain after shoulder surgery. This may represent an option when interscalene nerve block is not desired or contraindicated.

Comparison of Subacromial Injection and Interscalene Block for Immediate Pain Management After Arthroscopic Rotator Cuff Repair

PURPOSE

To compare the efficacy of a subacromial injection (SAI) with a single-shot interscalene block (ISB) for immediate postoperative pain relief after outpatient arthroscopic rotator cuff repair (ARCR).

METHODS

We performed a retrospective chart review of consecutive patients who underwent ARCR. Patients received either an ISB before the procedure or an SAI after the procedure. Preoperative baseline patient characteristics were collected and compared. Visual analog scale (VAS) pain scores were recorded preoperatively, at 15-minute intervals over a 120-minute period in the postanesthesia care unit (PACU), and at discharge. Differences in VAS scores between groups were compared with known values of the minimal clinically important difference, and the percentage of patients with VAS scores below the patient acceptable symptom state was tabulated. Differences between preoperative characteristics were assessed using the Mann-Whitney U, Fisher exact, or χ² test. The Mann-Whitney U test was also used to evaluate VAS scores and total time spent in the PACU between groups.

RESULTS

The median VAS score was significantly lower in the ISB group at PACU admission, at all intervals throughout the PACU stay, and at discharge (P < .0001). The median total time in the PACU was 107 minutes (25th percentile-75th percentile, 90-120 minutes) and 210 minutes (25th percentile-75th percentile, 175-274 minutes) in the ISB and SAI groups, respectively (P < .0001). Between-group differences in VAS scores were greater than the values of the minimal clinically important difference at each measured interval. A total of 98% and 67% of patients in the ISB and SAI groups, respectively, were discharged with VAS scores below the patient acceptable symptom state of 3.

CONCLUSIONS

Patients receiving an ISB experience significantly less pain than those receiving an SAI. In addition, they are discharged home from the PACU in half the time as patients receiving an SAI. On the basis of the comparative efficacy, an SAI cannot replace an ISB after ARCR. The ISB should therefore remain the standard of care as an adjunct to postoperative analgesia for patients who undergo outpatient ARCR.

LEVEL OF EVIDENCE

Level III, retrospective, comparative therapeutic trial.

Subomohyoid Anterior Suprascapular Block versus Interscalene Block for Arthroscopic Shoulder Surgery

Background

Interscalene brachial plexus block, the pain relief standard for shoulder surgery, is an invasive technique associated with important complications. The subomohyoid anterior suprascapular block is a potential alternative, but evidence of its comparative analgesic effect is sparse. The authors tested the hypothesis that anterior suprascapular block is noninferior to interscalene block for improving pain control after shoulder surgery. As a secondary objective, the authors evaluated the success of superior trunk (C5–C6 dermatomes) block with suprascapular block.

Methods

In this multicenter double-blind noninferiority randomized trial, 140 patients undergoing shoulder surgery were randomized to either interscalene or anterior suprascapular block with 15 ml of ropivacaine 0.5% and epinephrine. The primary outcome was area under the curve of postoperative visual analog scale pain scores during the first 24 h postoperatively. The 90% CI for the difference (interscalene-suprascapular) was compared against a –4.4-U noninferiority margin. Secondary outcomes included presence of superior trunk blockade, pain scores at individual time points, opioid consumption, time to first analgesic request, opioid-related side-effects, and quality of recovery.

Results

A total of 136 patients were included in the analysis. The mean difference (90% CI) in area under the curve of pain scores for the (interscalene-suprascapular) comparison was –0.3 U (–0.8 to 0.12), exceeding the noninferiority margin of –4.4 U and demonstrating noninferiority of suprascapular block. The risk ratio (95% CI) of combined superior trunk (C5–C6 dermatomes) blockade was 0.98 (0.92 to 1.01), excluding any meaningful difference in superior trunk block success rates between the two groups. When differences in other analgesic outcomes existed, they were not clinically important.

Conclusions

The suprascapular block was noninferior to interscalene block with respect to improvement of postoperative pain control, and also for blockade of the superior trunk. These findings suggest that the suprascapular block consistently blocks the superior trunk and qualify it as an effective interscalene block alternative.

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Randomized control trial of ultrasound-guided erector spinae block versus shoulder periarticular anesthetic infiltration for pain control after arthroscopic shoulder surgery: Study protocol clinical trial (SPIRIT compliant)

INTRODUCTION

Moderate to severe postoperative pain and associated opioid use may interfere with patients' well-being and course of recovery. Regional anesthetic techniques provide an opportunity for opioid sparing and improved patient outcomes. A new regional technique called the erector spinae plane (ESP) block has the potential to provide effective analgesia after shoulder arthroscopy with minimal risks and decreased opioid consumption. Our primary objective is to determine whether, in patients who undergo arthroscopic shoulder surgery, a preoperative ESP block reduces pain scores as compared to periarticular infiltration at the end of surgery. Additionally, we will also examine other factors such as opioid consumption, sensory block, adverse events, patient satisfaction, and persistent pain.

METHODS

This is a 2-arm, single-center, parallel-design, double-blind randomized controlled trial of 60 patients undergoing arthroscopic shoulder surgery. Eligible patients will be recruited in the preoperative clinic. Using a computer-generated randomization, with a 1:1 allocation ratio, patients will be randomized to either the ESP or periarticular infiltration group. Patients will be followed in hospital in the postanesthesia care unit, at 24 hours, and at 1 month. The study with be analyzed as intention-to-treat.

DISCUSSION

This study will inform an evidence-based choice in recommending ESP block for shoulder arthroscopy, as well as providing safety data. The merits of the study include its double dummy blinding to minimize observer bias, and its assessment of patient important outcomes, including pain scores, opioid consumption, and patient satisfaction. This study will also help provide an estimate of the incidence of side effects and complications of the ESP block.

TRIAL REGISTRATION NUMBER

NCT03691922; Recruited Date of registration: October 2, 2018.

Continuous suprascapular nerve block compared with single-shot interscalene brachial plexus block for pain control after arthroscopic rotator cuff repair

OBJECTIVES

We compared the analgesic efficacy of a continuous suprascapular nerve block (C-SSNB) and a single-shot interscalene brachial plexus block (S-ISNB) for postoperative pain management in patients undergoing arthroscopic rotator cuff repair.

METHODS

A total of 118 patients undergoing arthroscopic rotator cuff repair were randomly allocated to the S-ISNB or C-SSNB groups. Postoperative pain was assessed using the visual analog scale (VAS) at 1, 2, 6, 12, and 24 h postoperatively. Supplemental analgesic use was recorded as total equianalgesic fentanyl consumption.

RESULTS

The C-SSNB group showed significantly higher VAS scores at 0-1 h and 1-2 h after the surgery than the S-ISNB group (4.9±2.2 versus 2.3±2.2; p<0.0001 and 4.8±2.1 versus 2.4±2.3; p<0.0001, respectively). The C-SSNB group showed significantly lower VAS scores at 6-12 h after the surgery than the S-ISNB group (4.1±1.8 versus. 5.0±2.5; p=0.031). The C-SSNB group required significantly higher doses of total equianalgesic fentanyl in the post-anesthesia care unit than the S-ISNB group (53.66±44.95 versus 5.93±18.25; p<0.0001). Total equianalgesic fentanyl in the ward and total equianalgesic fentanyl throughout the hospital period were similar between the groups (145.99±152.60 versus 206.13±178.79; p=0.052 and 199.72±165.50 versus 212.15±180.09; p=0.697, respectively).

CONCLUSION

C-SSNB was more effective than S-ISNB at 6-12 h after the surgery for postoperative analgesia after arthroscopic rotator cuff repair.

Analgesic benefits and clinical role of the posterior suprascapular nerve block in shoulder surgery: a systematic review, meta-analysis and trial sequential analysis

The posterior suprascapular nerve block has been proposed as an analgesic alternative for shoulder surgery based on the publication of several comparisons with interscalene block that failed to detect differences in analgesic outcomes. However, quantification of the absolute treatment effect of suprascapular nerve block on its own, in comparison with no block (control), to corroborate the aforementioned conclusions has been lacking. This study examines the absolute analgesic efficacy of suprascapular nerve block compared with control for shoulder surgery. We systematically sought electronic databases for studies comparing suprascapular nerve block with control. The primary outcomes included postoperative 24-h cumulative oral morphine consumption and the difference in area under the curve for 24-h pooled pain scores. Secondary outcomes included the incidence of opioid-related side-effects (postoperative nausea and vomiting) and patient satisfaction. Data were pooled using random-effects modelling. Ten studies (700 patients) were analysed; all studies examined landmark-guided posterior suprascapular nerve block performed in the suprascapular fossa. Suprascapular nerve block was statistically but not clinically superior to control for postoperative 24-h cumulative oral morphine consumption, with a weighted mean difference (99%CI) of 11.41 mg (-21.28 to -1.54; p = 0.003). Suprascapular nerve block was also statistically but not clinically superior to control for area under the curve of pain scores, with a mean difference of 1.01 cm.h. Nonetheless, suprascapular nerve block reduced the odds of postoperative nausea and vomiting and improved patient satisfaction. This review suggests that the landmark-guided posterior suprascapular nerve block does not provide clinically important analgesic benefits for shoulder surgery. Investigation of other interscalene block alternatives is warranted.

Editorial Commentary: The Truth about Peripheral Nerve Blocks and Hip Arthroscopy

Peripheral nerve blocks targeting the fascia iliaca compartment have been used in attempts to improve postoperative pain after hip arthroscopy surgery. Recent level I evidence from randomized controlled trials have revealed injection of local anesthetic into the fascia iliaca compartment to be no better than sham injection for postoperative pain control, while contributing to decreased patient quadriceps strength and increased fall risk after surgery. The fascia iliaca compartment block is also inferior to local anesthetic injection at the surgery site for pain control. Results of these high-level studies show that routine preoperative use of the fascia iliaca compartment block is not recommended for hip arthroscopy.

Orthopaedic Shoulder Surgery in the Ambulatory Surgical Center: Safety and Outcomes

PURPOSE

To determine whether the risk of adverse events and readmission after non-arthroplasty shoulder surgery is influenced by the outpatient setting of surgical care and to identify risk factors associated with these adverse events.

METHODS

The Humana Claims Database was queried for all patients undergoing arthroscopic shoulder surgery and related open procedures in the hospital-based outpatient department (HOPD) or ambulatory surgical center (ASC) setting, using the PearlDiver supercomputer. Arthroplasty procedures were excluded because they carry a risk profile different from that of other outpatient surgical procedures. Outcome variables included unanticipated admission after surgery, readmission, deep vein thrombosis, pulmonary embolism, and wound infection within 90 days of surgery. The ASC and HOPD cohorts were propensity score matched, and outcomes were compared between them. Finally, logistic regression models were created to identify risk factors associated with unplanned admission after surgery.

RESULTS

A total of 84,658 patients met the inclusion criteria for the study: 28,730 in the ASC cohort and 56,819 in the HOPD cohort. The rates of all queried outcomes were greater in the HOPD cohort and achieved statistical significance. Sex, region, race, insurance status, comorbidity burden, anesthesia type, and procedural type were included in the regression analysis of unplanned admission. Factors associated with unplanned admission included increasing Charlson Comorbidity Index (odds ratio [OR], 1.16; 95% confidence interval [CI], 1.12-1.17; P < .001); HOPD service location (OR, 2.37; 95% CI, 2.18-2.58; P < .001); general anesthesia (OR, 1.34; 95% CI, 1.08-1.59; P = .008); male sex (OR, 2.58; 95% CI, 2.17-3.15; P = .007); and open surgery (OR, 2.35; 95% CI, 1.90-2.61; P < .001).

CONCLUSIONS

The lower rates of perioperative morbidity in the ASC cohort suggest that proper patient selection is taking place and lends reassurance to surgeons who are practicing or are considering practicing in an ASC. Patients to whom some or all the risk factors for unplanned admission apply (male sex, higher comorbidity burden, open surgery) may be more suitable for HOPDs because admission from an ASC can be difficult and potentially unsafe.

LEVEL OF EVIDENCE

Level III, comparative study.

Superior Trunk Block

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Background

Interscalene nerve blockade remains one of the most commonly used anesthetic and analgesic approaches for shoulder surgery. The high incidence of hemidiaphragmatic paralysis associated with the block, however, precludes its use among patients with compromised pulmonary function. To address this issue, recent studies have investigated phrenic-sparing alternatives that provide analgesia. None, however, have been able to reliably demonstrate surgical anesthesia without significant risk for hemidiaphragmatic paralysis. The utility of the superior trunk block has yet to be studied. The hypothesis was that compared with the interscalene block, the superior trunk block will provide noninferior surgical anesthesia and analgesia while sparing the phrenic nerve.

Methods

This randomized controlled trial included 126 patients undergoing arthroscopic ambulatory shoulder surgery. Patients either received a superior trunk block (n = 63) or an interscalene block (n = 63). The primary outcomes were the incidence of hemidiaphragmatic paralysis and worst pain score in the recovery room. Ultrasound was used to assess for hemidiaphragmatic paralysis. Secondary outcomes included noninvasively measured parameters of respiratory function, opioid consumption, handgrip strength, adverse effects, and patient satisfaction.

Results

The superior trunk group had a significantly lower incidence of hemidiaphragmatic paralysis compared with the interscalene group (3 of 62 [4.8%] vs. 45 of 63 [71.4%]; P &lt; 0.001, adjusted odds ratio 0.02 [95% CI, 0.01, 0.07]), whereas the worst pain scores in the recovery room were noninferior (0 [0, 2] vs. 0 [0, 3]; P = 0.951). The superior trunk group were more satisfied, had unaffected respiratory parameters, and had a lower incidence of hoarseness. No difference in handgrip strength or opioid consumption were detected. Superior trunk block was associated with lower worst pain scores on postoperative day 1.

Conclusions

Compared with the interscalene block, the superior trunk block provides noninferior surgical anesthesia while preserving diaphragmatic function. The superior trunk block may therefore be considered an alternative to traditional interscalene block for shoulder surgery.

Pectoralis-II Myofascial Block and Analgesia in Breast Cancer Surgery

Editor’s Perspective

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Background

Thoracic paravertebral block is the preferred regional anesthetic technique for breast cancer surgery, but concerns over its invasiveness and risks have prompted search for alternatives. Pectoralis-II block is a promising analgesic technique and potential alternative to paravertebral block, but evidence of its absolute and relative effectiveness versus systemic analgesia (Control) and paravertebral block, respectively, is conflicting. This meta-analysis evaluates the analgesic effectiveness of Pectoralis-II versus Control and paravertebral block for breast cancer surgery.

Methods

Databases were searched for breast cancer surgery trials comparing Pectoralis-II with Control or paravertebral block. Postoperative oral morphine consumption and difference in area under curve for pooled rest pain scores more than 24 h were designated as coprimary outcomes. Opioid-related side effects, effects on long-term outcomes, such as chronic pain and opioid dependence, were also examined. Results were pooled using random-effects modeling.

Results

Fourteen randomized trials (887 patients) were analyzed. Compared with Control, Pectoralis-II provided clinically important reductions in 24-h morphine consumption (at least 30.0 mg), by a weighted mean difference [95% CI] of −30.5 mg [−42.2, −18.8] (P &lt; 0.00001), and in rest pain area under the curve more than 24 h, by −4.7cm · h [−5.1, −4.2] or −1.2cm [−1.3, −1.1] per measurement. Compared with paravertebral block, Pectoralis-II was not statistically worse (not different) for 24-h morphine consumption, and not clinically worse for rest pain area under curve more than 24 h. No differences were observed in opioid-related side effects or any other outcomes.

Conclusions

We found that Pectoralis-II reduces pain intensity and morphine consumption during the first 24 h postoperatively when compared with systemic analgesia alone; and it also offers analgesic benefits noninferior to those of paravertebral block after breast cancer surgery. Evidence supports incorporating Pectoralis-II into multimodal analgesia and also using it as a paravertebral block alternative in this population.

Editorial Commentary: Mounting Evidence for a Landmark-Based Approach to Suprascapular Nerve Block

The surgeon-administered landmark-based approach for suprascapular nerve block (SNB) alone for postoperative pain relief after arthroscopic shoulder surgery as an alternative to interscalene nerve block (ISB) has been proven as effective as ultrasound-guided ISB. Questions remain about the SNB. For instance, is ultrasound guidance necessary for SNB or can it be performed using a landmark-based approach?

Ultrasound-Guided Proximal and Distal Suprascapular Nerve Blocks: A Comparative Cadaveric Study

Objectives

The primary aim of our study was to evaluate and compare the accuracy of ultrasound (US)-guided distal suprascapular nerve (dSSN) and proximal SSN (pSSN) blocks. Secondary aims were to compare the phrenic nerve involvement between groups and to describe the anatomical features of the sensory branches of the dSSN.

Methods

pSSN and dSSN blocks were performed in 14 cadavers (28 shoulders). Ten mL of 0.2% ropivacaine colored with methylene blue was injected under US guidance. Accuracy was determined using SSN staining and the distance between predefined anatomical landmarks and the targeted SSN. The phrenic nerve (PN) was judged to be colored or not. The distribution of the sensory branches that originate from the 14 dSSNs is described. Quantitative data are expressed as median (range).

Results

The pSSN was dyed more frequently than the dSSN (13 vs 11, P = 0.59). The targeted SSN was close to the suprascapular notch (1.3 [0–5.2] cm) and the origin of the SSN (1.4 [0.2–4.5] cm) for dSSN and pSSN blocks, respectively (P = 0.62). For dSSN blocks, the most frequent injection site was the supraspinous fossa. Three PNs were marked in pSSN blocks, compared with none in dSSN blocks (P = 0.22). Three sensory branches were identified for all 14 dSSNs: the medial subacromial branch, the lateral subacromial branch, and the posterior glenohumeral branch.

Conclusions

US-guided pSSN and dSSN blocks can be realized with accuracy. A distal approach to the SSN could be an alternative to interscalene brachial plexus block for the management of postoperative pain after shoulder surgery in high–respiratory risk patients.

Upper trunk block for shoulder analgesia with potential phrenic nerve sparing: a preliminary anatomical report

BACKGROUND AND OBJECTIVES

Ipsilateral phrenic nerve palsy (PNP) is an undesirable side of conventional approaches to interscalene brachial plexus blocks. The purpose of this study was to demonstrate whether or not the phrenic nerve can be spared by dye when injected at the division of the upper trunk of the brachial plexus.

METHODS

Under ultrasound guidance, 5 mL of radiolabeled dye was injected between the anterior and posterior division of the upper trunk in two fresh, cryopreserved cadavers. CT scan analysis, cadaveric dissection, and cryosectioning were performed to examine the spread of the injectate.

RESULTS

We found staining of the injectate over the entire upper trunk with its anterior and posterior divisions, the suprascapular nerve under the omohyoid muscle and the lateral pectoralis nerve, and the C5 and C6 roots. The middle trunk was partially stained. There was no evidence of dye staining of the lower trunk, anterior aspect of the anterior scalene muscle, or the phrenic nerve.

CONCLUSIONS

Our study offers an anatomical basis for the possibility of providing shoulder analgesia and avoiding a PNP.

Ultrasound-guided subomohyoid suprascapular nerve block and phrenic nerve involvement: a cadaveric dye study

Backgrounds and objectives

The anterior approach to the subomohyoid suprascapular (SOS) nerve is a new, technically easy and reliable regional anesthesia technique for postoperative shoulder analgesia. However, due to its proximity, the injectate may spread to the brachial plexus and phrenic nerve. The goal of this anatomic study with dye injection in the subomohyoid space and subsequent cadaver dissection was to establish the likely spread of local anesthesia and the extent of brachial plexus and phrenic nerve involvement resulting from ultrasound-guided SOS nerve block.

Methods

The suprascapular nerve (SSN) under the inferior belly of omohyoid muscle in the posterior triangle of the neck was identified. Using a contrast dye, 10 ultrasound-guided SOS nerve injections of 5 mL were done bilaterally, in five fresh cadavers. The area was then dissected to evaluate the spread of the contrast dye in the immediate proximity of the brachial plexus, phrenic and SSN.

Results

The SSN and omohyoid muscle were easily identified on each cadaver. SOS nerve staining with contrast dye was seen in 90% of dissections. The superior trunk was stained in 90% and the middle trunk was stained in 80% of dissections. The inferior trunk was stained in 20% of dissections. A spread of dye around the SSN was observed in 90% and the phrenic nerve was mildly stained in 20% of the dissections.

Conclusion

In-plane ultrasound-guided needle injection with a 5 mL volume for SOS block was sufficient to stain the SSN. This conservative volume involved other parts of the brachial plexus and may potentially spread to the phrenic nerve. Further clinical studies are required for confirmation.

Regional Anesthesia in the Combat Setting: Are ACGME Requirements Enough?

Introduction

Updated Joint Trauma System Clinical Practice Guidelines (CPG) indicate regional anesthesia and pain management (RAAPM) are important for combat casualty care. However, it is unclear whether military anesthesiology residents are receiving adequate RAAPM training to meet the CPGs. The goal of this study was to conduct a preliminary evaluation of resident-completed combat-relevant regional anesthesia procedures. It was hypothesized that most residents would perform an adequate number of each procedure to presume proficiency.

Materials and Methods

Resident-performed, combat-relevant regional anesthesia procedure frequency was extracted from a database maintained at a military anesthesiology residency program. Data collection was limited to a 1-year period. Univariate statistics described procedure distributions, frequencies, and proportion of residents achieving pre-defined, empirically-supported experience criteria for each technique. Analyses examined proportional differences in meeting experience criteria by training-year.

Results

Residents (N = 41) performed a variety of procedures. Simple procedures, such as saphenous peripheral nerve blocks, were performed at a greater frequency than more complicated procedures such as thoracic epidurals, continuous peripheral nerve blocks, and transverse abdominus plane blocks. The majority of residents met experience criteria for four out of the eight measured combat-relevant blocks. There were no proportional differences in meeting procedural experience criteria across the different training levels.

Conclusions

These results suggest a possible gap between the needs of the Military Health System during conflict and current residency training experiences. Reasons for this gap, as well as solutions, are explored.

[C5-6 nerve root block technique for postoperative analgesia of shoulder arthroscope: a randomized controlled trial]

OBJECTIVE

To compare the effects of ultrasound-guided interscalene brachial plexus block and C5-6 nerve root block for analgesia after shoulder arthroscopy.

METHODS

In the study, 40 patients of ASA I-II were selected for elective general anesthesia to repair the shoulder ligament rupture in Peking University Third Hospital, who were randomly divided into two groups, respectively for the intermuscular brachial plexus block group (group I) and C5-6 nerve root block group (group C), n=20. The forty patients underwent ultrasound-guided brachial plexus block or C5-6 nerve root block before general anesthesia. Group I: 0.2% ropivacaine 10 mL was injected into brachial plexus intermuscular approach; Group C: 0.2% ropivacaine 10 mL was injected around the nerve roots of C5 and C6, and the ultrasound images showed that the liquid wrapped nerve roots. The time of sensory and motor block after puncture, operation time, the time of postoperative analgesia, numerical rating scale (NRS) scores at 1, 6, 12, and 24 h postoperatively and the finger movements were recorded. The adverse drug reactions and the patient satisfaction were recorded. The primary end point was the study of shoulder rest and movement pain in the patients with postoperative nerve blockage; the secondary end point was the patient's limb movements and thepatient satisfaction.

RESULTS

The duration of analgesia was (571.50±70.11) min in group I and (615.60±112.15) min in group C, and there was no difference between the two groups (P>0.05). The static and dynamic NRS scores at 1, 6, and 12 h in group C were lower than those in group I (P<0.05). There was no difference in static and dynamic NRS scores between the two groups during 24 hours (P>0.05). There was a significant difference in grade of muscle strength between group C [5(4,5)] and group I [4(2,4)] in the patients with nerve block hind limb (P<0.01), and there were significant differences between the two groups' sensation in the radial nerve group C [1(0,2)] and group I [2(1,2)], the median nerve group C [0(0,2)] and group I [2(1,2)], and the ulnar nerves group C [0(0,1)] and group I [1(1,2)] (P<0.01). There was no statistical difference between the two groups in the sencation of the shoulder, group C 2(1,2) and group I 2(1,2) , P>0.05. Compared with group I 8(6,9), group C 9(8,10) was a significant difference in satisfaction (P<0.01).

CONCLUSION

Interscalene brachial plexus block and C5-6 nerve root block could satisfy the needs of analgesia after shoulder arthroscopy, but C5-6 nerve root blockage does not limit the limb activity, the numbness is less, and the patient's satisfaction is higher.

Echo-guided invasive pain therapy: indications and limitations

PURPOSE OF REVIEW

The purposes of this review are to summarize the advantages and limitations of ultrasound-guided pain interventions, and to illustrate those interventions with peripheral, axial and musculoskeletal pain procedures.

RECENT FINDINGS

With the capability of locating the interfascial plane, ultrasonography has led to the emergence of a series of plane blocks for the thoracoabdominal region in the recent decade.Ultrasonography for musculoskeletal procedures has been of growing interest because of the major advantage of direct visualization and scanning of various soft tissues and real-time spread in the injectate, thereby enhancing precision and efficacy, reducing risk of trauma and avoidance of radiation. For spine and intra-articular structures, ultrasonography is complicated by the bony shadow artefact and often deep location of the structure, making acquisition of ultrasound image challenging. Despite these difficulties, there is growing interest in applying ultrasonography for cervical spine and sacroiliac joint procedures.

SUMMARY

Pain intervention under ultrasound guidance is particularly valuable in peripheral and musculoskeletal procedures. There is growing interest of its application in cervical spine and sacroiliac joint. More outcome studies are required in the future to make ultrasound-guided pain intervention as the established procedure.

Anatomical study of the innervation of glenohumeral and acromioclavicular joint capsules: implications for image-guided intervention

BACKGROUND AND OBJECTIVES

In 2011, chronic shoulder joint pain was reported by 18.7 million Americans. Image-guided radiofrequency ablation has emerged as an alternative intervention to manage chronic shoulder joint pain. To optimize the effectiveness of shoulder denervation, it requires a detailed understanding of the nerve supply to the glenohumeral and acromioclavicular joints relative to landmarks visible with image guidance. The purpose of this cadaveric study was to determine the origin, course, relationships to bony landmarks, and frequency of articular branches innervating the glenohumeral and acromioclavicular joints.

METHODS

Fifteen cadaveric specimens were meticulously dissected. The origin, course, and termination of articular branches supplying the glenohumeral and acromioclavicular joints were documented. The frequency of each branch was determined and used to generate a frequency map that included their relationships to bony and soft tissue landmarks.

RESULTS

In all specimens, the posterosuperior quadrant of the glenohumeral joint was supplied by suprascapular nerve; posteroinferior by posterior division of axillary nerve; anterosuperior by superior nerve to subscapularis; and anteroinferior by main trunk of axillary nerve. Less frequent innervation was found from lateral pectoral nerve and posterior cord. The acromioclavicular joint was found to be innervated by the lateral pectoral and acromial branch of suprascapular nerves in all specimens. Bony and soft tissue landmarks were identified to localize each nerve.

CONCLUSIONS

The frequency map of the articular branches supplying the glenohumeral and acromioclavicular joints, as well as their relationship to bony and soft tissue landmarks, provide an anatomical foundation to develop novel shoulder denervation and perioperative pain management protocols.

Interscalenic versus suprascapular nerve block: can the type of block influence short- and long-term outcomes? An observational study

BACKGROUND

While interscalenic nerve block (INB) is still considered the gold standard for shoulder arthroscopy, its postoperative analgesic effectiveness has recently been called into question. Meanwhile, in light of its high-quality postoperative pain relief, a renewed interest has emerged in suprascapular nerve block (SNB). The first aim of our study was to compare the postoperative analgesia effects of these two types of block at two, four and six hours after surgery. We also assessed shoulder functional recovery over a 6-month follow-up period.

METHODS

All patients requiring arthroscopic shoulder surgery for rotator cuff repair during the study period were enrolled. INB or SNB was performed under ultrasound guidance. The patients underwent general anaesthesia. Numerical rate scores (NRS) at rest and in motion at two, four and six postoperative hours were recorded.

RESULTS

Over two years, 280 patients were screened. Of these, 136 were excluded. Pain scores after surgery were lower at two hours in INB at rest (0.70±1.50 versus 2.1±2.2; P<0.0067) and after movement (1.0±2.2 versus 2.5±2.3; P=0.01). A significant difference in terms of arm extrarotation degrees at week 6 and month 2 (P<0.01) in SNB was found.

CONCLUSIONS

INB showed better analgesic efficacy in the immediate postoperative period. Both types of block showed similar results in terms of functional recovery over the six-month follow-up. SNB without motor block seems matched better with ambulatory surgery and with an early rehabilitation program.

Comparison of Anterior Suprascapular, Supraclavicular, and Interscalene Nerve Block Approaches for Major Outpatient Arthroscopic Shoulder Surgery

Background

The interscalene nerve block provides analgesia for shoulder surgery, but is associated with diaphragm paralysis. One solution may be performing brachial plexus blocks more distally. This noninferiority study evaluated analgesia for blocks at the supraclavicular and anterior suprascapular levels, comparing them individually to the interscalene approach.

Methods

One hundred-eighty-nine subjects undergoing arthroscopic shoulder surgery were recruited to this double-blind trial and randomized to interscalene, supraclavicular, or anterior suprascapular block using 15 ml, 0.5% ropivacaine. The primary outcome was numeric rating scale pain scores analyzed using noninferiority testing. The predefined noninferiority margin was one point on the 11-point pain scale. Secondary outcomes included opioid consumption and pulmonary assessments.

Results

All subjects completed the study through the primary outcome analysis. Mean pain after surgery was: interscalene = 1.9 (95% CI, 1.3 to 2.5), supraclavicular = 2.3 (1.7 to 2.9), suprascapular = 2.0 (1.4 to 2.6). The primary outcome, mean pain score difference of supraclavicular–interscalene was 0.4 (–0.4 to 1.2; P = 0.088 for noninferiority) and of suprascapular–interscalene was 0.1 (–0.7 to 0.9; P = 0.012 for noninferiority). Secondary outcomes showed similar opioid consumption with better preservation of vital capacity in the anterior suprascapular group (90% baseline [P &lt; 0.001]) and the supraclavicular group (76% [P = 0.002]) when compared to the interscalene group (67%).

Conclusions

The anterior suprascapular block, but not the supraclavicular, provides noninferior analgesia compared to the interscalene approach for major arthroscopic shoulder surgery. Pulmonary function is best preserved with the anterior suprascapular nerve block.

Introduction to systematic review and meta-analysis

Systematic reviews and meta-analyses present results by combining and analyzing data from different studies conducted on similar research topics. In recent years, systematic reviews and meta-analyses have been actively performed in various fields including anesthesiology. These research methods are powerful tools that can overcome the difficulties in performing large-scale randomized controlled trials. However, the inclusion of studies with any biases or improperly assessed quality of evidence in systematic reviews and meta-analyses could yield misleading results. Therefore, various guidelines have been suggested for conducting systematic reviews and meta-analyses to help standardize them and improve their quality. Nonetheless, accepting the conclusions of many studies without understanding the meta-analysis can be dangerous. Therefore, this article provides an easy introduction to clinicians on performing and understanding meta-analyses.