Suprascapular nerve block as a method of preemptive pain control in shoulder surgery

Assessment of 2 distinct anatomical landmarks for suprascapular nerve injection: a cadaveric study

BACKGROUND

The suprascapular nerve block (SSNB) is a commonly used procedure for the management of pain in various shoulder pathologies. Both image-guided and landmark-based techniques have been utilized successfully for SSNB, though more consensus is needed regarding the optimal method of administration. This study aims to evaluate the theoretical effectiveness of a SSNB at 2 distinct anatomic landmarks and propose a simple, reliable way of administration for future clinical use.

METHODS

Fourteen upper extremity cadaveric specimens were randomly assigned to either receive an injection 1 cm medial to the posterior acromioclavicular (AC) joint vertex or 3 cm medial to the posterior AC joint vertex. Each shoulder was injected with a 10 ml methylene blue solution at the assigned location, and gross dissection was performed to evaluate the anatomic diffusion of the dye. The presence of dye was specifically assessed at the suprascapular notch, supraspinatus fossa, and spinoglenoid notch to determine the theoretic analgesic effectiveness of a SSNB at these 2 injection sites.

RESULTS

Methylene blue diffused to the suprascapular notch in 57.1% of the 1-cm group and 100% of the 3-cm group, the supraspinatus fossa in 71.4% of the 1-cm group and 100% of the 3-cm group, and the spinoglenoid notch in 100% of the 1-cm group and 42.9% of the 3-cm group.

CONCLUSION

Given its superior coverage at the more proximal sensory branches of the suprascapular nerve, a SSNB injection performed 3 cm medial to the posterior AC joint vertex provides more clinically adequate analgesia than an injection site 1 cm medial to the AC junction. Performing a SSNB injection at this location allows for an effective method of anesthetizing the suprascapular nerve.

Clinical Results Following Conservative Management of Tarsal Tunnel Syndrome Compared With Surgical Treatment: A Systematic Review

Introduction

Posterior tarsal tunnel syndrome involves entrapment of the posterior tibial nerve as it travels in the groove posterior to the medial malleolus. Conventional wisdom dictates that patients with tarsal tunnel syndrome be treated with conservative treatment and medical management, with surgical options available for patients with refractory symptoms and good candidacy. Minimally invasive options for neuropathic entrapment syndromes have developed in recent years and may provide a therapeutic role in tarsal tunnel syndrome.

Objective

The present investigation provides a summary of the current state of knowledge on tarsal tunnel syndrome and a comparison between minimally invasive and surgical treatment options.

Methods

The literature search was performed in Mendeley. Search fields were varied until redundant. All articles were screened by title and abstract and a preliminary decision to include an article was made. A full-text screening was performed on the selected articles. Any question regarding the inclusion of an article was discussed by 3 authors until an agreement was reached.

Results

Most commonly tarsal tunnel syndrome is idiopathic. Other reported causes include post-traumatic, lipomas, cysts, ganglia, schwannomas, ganglia, varicose plantar veins, anatomic anomalies, and systematic inflammatory conditions. Several risk factors have been described including female gender, athletic participation, hypothyroidism, diabetes mellitus, systemic sclerosis, chronic renal failure, and hemodialysis use. A few recent studies demonstrate anatomic variants that have not previously been summarized. Three articles describe clinical outcomes after conservative treatment with acceptable results for first line treatment. Two primary articles report on the use of minimally invasive treatment for tarsal tunnel syndrome. Fourteen articles report on the clinical outcomes after surgical management.

Conclusion

Clinical understanding of tarsal tunnel syndrome has evolved significantly, particularly with regards to the pathoanatomy of the tarsal canal over the past twelve years. A few novel anatomic studies shed light on variants that can be helpful in diagnosis. Conservative management remains a good option that can resolve the symptoms of many patients. As more prospective cohorts and clinical trials are performed on minimally invasive options, pulsed radiofrequency and neuromodulation may evolve to play a larger role in the treatment of this condition. Currently, surgical treatment is only pursued in a very select group of patients with refractory symptoms that do not respond to medical or minimally invasive options. Surgical outcomes in the literature are good and current evidence is stronger than that for minimally invasive options.

A prospective, comparative study of subacromial corticosteroid injection and subacromial corticosteroid injection plus suprascapular nerve block in patients with shoulder impingement syndrome

INTRODUCTION

Efforts are recently focused on the management of shoulder impingement syndrome (SIS) with a conservative and targeted approach because of its psychosocial impact, reduction in the quality of life, the cost to the economy and its negative effect on daily activities. Therefore, many studies have been designed to evaluate and compare the effectiveness of different treatments. The main purpose of this study was to identify the effect of combination of subacromial corticosteroid injection (SCI) and suprascapular nerve block (SSNB) on shoulder impingement syndrome (SIS).

MATERIALS AND METHODS

66 patients with SIS were randomly divided into two groups (33 patients per group): Group 1: SCI; Group 2: SCI plus SSNB. The estimation of the severity of pain by the visual analogue scale (VAS) and shoulder disability using quick DASH (Disabilities of the Arm, Shoulder and Hand) were assessed at baseline and 1, 3 months post-injection.

RESULTS

The mean age of patients was 55.55 ± 10.42 years in Group 1 and 57.24 ± 12.75 years in Group 2. In steroid group, pre- and post-treatment (at 1 and 3 months) VAS/quickDASH scores were 8.64 ± 0.99/78.03 ± 9.24, 2.09 ± 0.84/15.58 ± 7.23 and 3.06 ± 1.12/25.06 ± 8.74, respectively. In steroid plus SSNB group, pre- and post-treatment (at 1 and 3 months) VAS/quickDASH scores were 8.45 ± 0.90/75.15 ± 9.86, 1.24 ± 0.43/10.88 ± 2.14 and 1.51 ± 0.56/15.51 ± 5.04, respectively. Both treatment groups showed a significant relief of pain at 1 and 3 months post-injection (p < 0.05). However, the VAS and quickDASH scores at 1 and 3 months were significantly lower in Group 2 versus Group 1 (p < 0.05).

CONCLUSION

The combination of SCI and SSNB seems to produce the long-term effect in pain relief and functional improvement.

Proximal vs Distal Approach of Ultrasound-guided Suprascapular Nerve Block for Patients With Adhesive Capsulitis of the Shoulder: Prospective Randomized Controlled Trial

OBJECTIVES

To evaluate the early clinical outcomes of ultrasound (US)-guided suprascapular nerve block (SSNB) using a proximal approach compared with a distal approach for outpatient treatment of adhesive capsulitis.

DESIGN

Randomized controlled trial.

SETTING

Outpatient clinic PARTICIPANTS: Participants (N=47) with symptomatic adhesive capsulitis.

INTERVENTIONS

Participants were randomly assigned to either US-guided SSNB using a proximal approach (n=23, proximal group) or a distal approach (n=24, distal group).

MAIN OUTCOME MEASURES

The primary outcome measure was the visual analog scale (VAS) for pain at week 12. Secondary outcomes included the American Shoulder Elbow Surgeon's (ASES) score, University California Los Angeles score, Short Form-36 mental and physical component summaries, and range of motion. All patients completed clinical follow-up at 2, 6, and 12 weeks after treatment. On US images, depth and insertion angle of needle during injection were measured.

RESULTS

The VAS significantly improved in both groups at week 12. After treatment, no significant differences were found in early clinical outcomes (weeks 2, 6, and 12) between groups (all P>.05), except that ASES at 2 weeks showed a significantly higher score in the distal group than in the proximal group (87.1±4.8 and 83.0±6.3, respectively; P=.014). The mean depth and insertion angle of needle was significantly lower (depth: 13.4±3.9 and 30.6±4.3 mm, respectively; P<.001; insertion angle: 19.6°±6.4° and 38.7°±5.8°; P<.001) in the proximal group than in the distal group.

CONCLUSIONS

This study demonstrated that proximal approach of US-guided SSNB provided favorable short-term outcomes of pain and functional improvement and that outcomes were comparable to those of the distal approach in adhesive capsulitis. The suprascapular nerve was located more superficially and easily identified in the proximal approach, suggesting that this method might improve the accuracy of injection.

Innervation of the acromioclavicular joint by the suprascapular nerve

BACKGROUND

The suprascapular nerve is largely responsible for the majority of the sensory innervation of the acromioclavicular joint. In this anatomical study, we describe, in detail, the anatomy of the sensory innervation of the acromioclavicular joint by the branches of the suprascapular nerve.

METHODS

Twenty-seven shoulders from 17 cadaveric specimens were carefully dissected to identify the course of the suprascapular nerve, with the main focus being on the sensory innervation of the acromioclavicular joint. Nine specific measurements of the acromioclavicular joint sensory nerves were made of each shoulder in relation to distinct anatomical landmarks to determine the mean location and course of these nerves.

RESULTS

In all 27 shoulders (100%), a sensory branch to the acromioclavicular joint with a proximal origin from the suprascapular nerve could be depicted ("first sensory branch"). The mean length of this branch was 4.3 cm (range: 3.3-5.3 cm). In 14 shoulders (52%), a further sensory branch of the suprascapular nerve innervating the posterior acromioclavicular joint capsule could be identified ("second sensory branch").

DISCUSSION

A detailed anatomical description of the sensory innervation of the acromioclavicular joint from suprascapular nerve branches was performed, which can potentially aid in the development of more focused anesthetic blockades and acromioclavicular joint denervation procedures.

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.

Suprascapular Nerve Blockade for Postoperative Pain Control After Arthroscopic Shoulder Surgery: A Systematic Review and Meta-analysis

Background:

Regional nerve blocks are commonly used to manage postoperative pain after arthroscopic shoulder procedures. The interscalene brachial plexus block (ISB) is commonly used; however, because of the reported side effects of ISB, the use of a suprascapular nerve block (SSNB) has been described as an alternative strategy with fewer reported side effects.

Purpose:

To examine the efficacy of SSNB for pain control after shoulder arthroscopy compared with ISB as well as anesthesia without a nerve block.

Study Design:

Systematic review; Level of evidence, 1.

Methods:

Three databases (PubMed, MEDLINE, and EMBASE) were searched on April 20, 2018, to systematically identify and screen the literature for randomized controlled trials (RCTs). A meta-analysis of standard mean differences (SMDs) was performed to pool the estimated effects of the nerve blocks.

Results:

The search identified 14 RCTs that included 1382 patients, with a mean age of 54 years (SD, 13 years). The mean follow-up time was 3 days (range, 24 hours to 6 weeks). Postoperative pain control was significantly more effective in the SSNB groups compared with the control groups within 1 hour (SMD, –0.76; 95% CI, –1.45 to –0.07; P = .03) and 4 to 6 hours (SMD, –0.81; 95% CI, –1.53 to –0.09; P = .03) postoperatively. However, pain control was significantly less effective in the SSNB groups compared with ISB within 1 hour (SMD, 0.87; 95% CI, 0.28 to 1.46; P = .004). No major complications were noted in the SSNB groups, and minor complications such as hoarseness and prolonged motor block were significantly less common for SSNB compared with ISB.

Conclusion:

Although not more efficacious than ISB in terms of pain control for patients undergoing shoulder arthroscopy, SSNB provides significantly improved pain control in comparison with analgesia without a nerve block. Moreover, few major and minor complications are associated with SSNB reported across the literature.

Suprascapular Nerve Pathology: A Review of the Literature

Background:

Suprascapular nerve pathology is a rare diagnosis that is increasingly gaining popularity among the conditions that cause shoulder pain and dysfunction. The suprascapular nerve passes through several osseoligamentous structures and can be compressed in several locations.

Methods:

A thorough literature search was performed using online available databases in order to carefully define the pathophysiology and to guide diagnosis and treatment.

Results:

Suprascapular neuropathy diagnosis is based on a careful history and a thorough clinical and radiological examination. Although the incidence and prevalence of the condition remain unknown, it is highly diagnosed in specific groups (overhead athletes, patients with a massive rotator cuff tear) probably due to higher interest. The location and the etiology of the compression are those that define the treatment modality.

Conclusion:

Suprascapular neuropathy diagnosis is based on a careful history and a thorough clinical and radiological examination. The purpose of this article is to describe the anatomy of the suprascapular nerve, to define the pathophysiology of suprascapular neuropathy and to present methodically the current diagnostic and treatment strategies.

Anatomical study of the articular branch of the lateral pectoral nerve to the shoulder joint

PURPOSE

The purpose of this study was to document the distribution of the articular branch of the lateral pectoral nerve (LPN) to the shoulder and to identify a suitable point for its blockade.

METHODS

This study involved the dissection of 43 shoulders of 22 unembalmed cadavers (6 male and 16 female) to identify the LPN and its articular branch to the shoulder. To identify the suitable anatomical point for blocking the articular branch of the LPN, several anatomical landmarks around the shoulder were measured.

RESULTS

The articular branch of the LPN to the shoulder was present in 29 of 43 cases (67.4 %). The appropriate point to block the articular branch of the LPN was identified at a mean distance of 1.5 cm below the clavicle, on the line connecting the closest points between the clavicle and the coracoid process, and at a mean depth of 1.0 cm from the skin.

CONCLUSION

The articular branch of the LPN to the shoulder, as well as the muscular and cutaneous branches of the LPN, covers a portion of the shoulder joint with suprascapular and axillary nerves. Surgeons might consider a peripheral block of the suprascapular, axillary, and LPNs to provide maximum block coverage after shoulder joint surgery.

Blind suprascapular and axillary nerve block for post-operative pain in arthroscopic rotator cuff surgery

PURPOSE

The goal of the study was to evaluate the efficacy of additional axillary nerve block (ANB) with suprascapular nerve block (SSNB) and patient-controlled anaesthesia (PCA) with no device assistance after arthroscopic rotator cuff repair. The hypothesis is that patients with intravenous (IV) PCA and the blockade of the two main nerves (SSNB + ANB) experienced lesser pain than patients with IV PCA or IV PCA + SSNB.

METHODS

The 114 patients undergoing arthroscopic rotator cuff repair were allocated randomly to three groups as follows: group I, intravenous PCA pumps (only PCA); group II, IV PCA + SSNB using a blind technique (PCA + SSNB); and group III, IV PCA + SSNB + ANB using a blind technique (PCA + SSNB + ANB). Pain visual analogue scale (VAS) scores were evaluated at 1, 6, 12, 24, 36, and 48 post-operative hours. Furthermore, the degree of pain was compared according to cuff tear size.

RESULTS

The pain VAS score of group III was lower than that of the other two groups and was significantly lower at post-operative hours 1, 6, and 12. In addition, the larger cuff tear tended to be indicative of greater pain. However, all groups experienced rebound pain.

CONCLUSION

PCA + SSNB + ANB using a blind technique is a better pain control method than PCA + SSNB and only PCA during the initial 12 post-operative hours. PCA + SSNB + ANB is a cost-effective, time-saving, and easily performed method for post-operative pain control as an axis of multimodal pain control strategy.

LEVEL OF EVIDENCE

II.

Suprascapular nerve injury: A cause to consider in shoulder pain and dysfunction

Suprascapular nerve injury is increasingly being recognized as an important cause of shoulder dysfunction. The non-specific clinical features of suprascapular nerve injury can make diagnosis difficult. However, it is essential for clinicians to consider it as part of the differential diagnoses in patients with vague pain or sensory disturbances over the posterosuperior part of their shoulder or have unexplained atrophy and weakness of their supraspinatus or infraspinatus muscle. Electrodiagnostic studies are useful in confirming and localising the nerve injury, while MRIs can be employed to determine the cause of nerve injury and assess the integrity of the rotator cuff muscles. Isolated suprascapular nerve injury can be managed with a trial of conservative management for at least 6 months. Subsequently, decompression of the nerve through open or arthroscopic techniques can be considered - both are associated with high rates of pain relief and functional improvement.

Post operative pain management in shoulder surgery: Suprascapular and axillary nerve block by arthroscope assisted catheter placement

BACKGROUND

Postoperative pain management is the part of shoulder surgery to improve patient satisfaction, start rehabilitation process rapidly and decrease for hospital stay. Various treatment modalities have been used for pain management, but they have some limitations, side effects and risks. Throughout intraoperative and postoperative period, nerve blocks have been used more popularly than others because of efficacy. For the regional nerve block, local anesthetic should be infiltrated close to the nerve for maximum effect. Consequently, aim of this study was to evaluate analgesic efficacy when catheters are placed with assistance of arthroscope to block suprascapular and axillary nerves in patients undergoing arthroscopic repair of rotator cuff under general anesthesia.

MATERIALS AND METHODS

24 patients (5 males, 19 females; mean age: 54.3 years) who underwent arthroscopic repair of rotator cuff between June 2014 and September 2014 and were catheterized to block suprascapular and axillary nerves during shoulder arthroscopy were included in the study. Clinical outcomes were assessed using visual analog scale (VAS) scores preoperatively and at 0 h, 6 h, 12 h, 18 h, 24 h, and postoperative day 2.

RESULTS

Preoperative and postoperative 0 h, 6 h, 12 h, 18 h, 24 h, and day 2 mean VAS scores were 6.38 ± 0.77, 0.44 ± 0.42, 0.58 ± 0.42, 0.63 ± 0.40, 0.60 ± 0.44, 0.52 ± 0.42, and 1.55 ± 0.46, respectively. No statistical difference was found among 0 h, 6 h, 12 h, 18 h, and 24 h time points; however, comparison of postoperative day 2 and postoperative 0 h, 6 h, 12 h, 18h and 24 h VAS scores showed statistically significant difference (P < 0.05). All patients were discharged at the end of 24 h with no complication. The mean time (in minutes) required for blocking suprascapular nerve and axillar nerve were 14.38 ± 3.21 and 3.75 ± 0.85, respectively.

CONCLUSION

These results demonstrated that blocking two nerves with arthroscopic approach was an excellent pain management method in postoperative period. Accordingly, patients could recover rapidly and patients' satisfaction could be improved.

Florid Suprascapular Neuropathy after Primary Rotator Cuff Repair Attributed to Suprascapular Notch Constriction in the Setting of Double Crush Syndrome

This report describes a patient who had an open repair of a small supraspinatus tendon tear performed 6 months after an arthroscopic acromioplasty with debridement had failed to provide pain relief. Three months prior to the tendon repair, he had a two-level cervical spine discectomy and fusion (C4-5, C5-6) that improved his neck pain. Florid suprascapular neuropathy was detected 10 weeks after the open rotator cuff repair. Evidence of some nerve recovery resulted in a long period of observation. But unsatisfactory improvement warranted decompression of the suprascapular notch, which was found to be very stenotic. At surgery, there was no evidence of neuroma, cyst, or other compressing lesion or tissue. Therefore, it was ultimately hypothesized that there was an exacerbation of a preexisting, but clinically unrecognized, entrapment of the suprascapular nerve in the suprascapular notch in the setting of cervical radiculopathy (primarily C5). Retrospectively it was also concluded that had this compressive etiology been recognized, it would have favored prompt decompression rather than the long observation period. Three years was required to achieve a good result following suprascapular notch decompression. The underlying C5 radiculopathy may have created a "double crush syndrome" that contributed to the propensity for injury and the prolonged recovery. There should be heightened awareness of this problem in patients who do not have satisfactory improvement in shoulder pain from previous shoulder and neck surgery.

The role of the peripheral and central nervous systems in rotator cuff disease

Rotator cuff (RC) disease is an extremely common condition associated with shoulder pain, reduced functional capacities, and impaired quality of life. It primarily involves alterations in tendon health and mechanical properties that can ultimately lead to tendon failure. RC tendon tears induce progressive muscle changes that have a negative impact on surgical reparability of the RC tendons and clinical outcomes. At the same time, a significant base of clinical data suggests a relatively weak relationship between RC integrity and clinical presentation, emphasizing the multifactorial aspects of RC disease. This review aims to summarize the potential contribution of peripheral, spinal, and supraspinal neural factors that may (1) exacerbate structural and functional muscle changes induced by tendon tear, (2) compromise the reversal of these changes during surgery and rehabilitation, (3) contribute to pain generation and persistence of pain, (4) impair shoulder function through reduced proprioception, kinematics, and muscle recruitment, and (5) help explain interindividual differences and response to treatment. Given the current clinical and scientific interest in peripheral nerve injury in the context of RC disease and surgery, we carefully reviewed this body of literature with a particular emphasis on suprascapular neuropathy that has generated a large number of studies in the past decade. Within this process, we highlight the gaps in current knowledge and suggest research avenues for scientists and clinicians.

Efficacy of direct arthroscopy-guided suprascapular nerve block after arthroscopic rotator cuff repair: a prospective randomized study

PURPOSE

The purpose of this study was to evaluate the outcomes of arthroscopy-guided direct suprascapular nerve block performed after arthroscopic rotator cuff repair.

METHODS

In the present prospective, randomized, double-blinded clinical study, 30 patients were divided into two groups: 15 patients (group I) were treated with arthroscopy-guided suprascapular nerve block using 10 mL 0.5 % ropivacaine with 1:200,000 epinephrine, and 15 patients (group II) were treated with placebo using 10 mL 0.9 % saline after arthroscopic rotator cuff repair. Patient pain levels were measured using the visual analog scale (VAS) at 1, 3, 6, 12, 18, and 24 h post-operatively. Additionally, the number of boluses and total amount of fentanyl dispensed by patient-controlled analgesia administration during the 24-h post-operative period were evaluated.

RESULTS

VAS scores did not differ significantly between groups I and II during the 24-h post-operative period, but mean fentanyl bolus consumption was significantly less in group I compared with group II (p = 0.015).

CONCLUSION

Arthroscopy-guided suprascapular nerve block at the end of a rotator cuff repair was safe and less time-consuming than expected. Although this procedure did not significantly reduce the post-operative pain, the post-operative need for fentanyl boluses as analgesia was reduced significantly, and it would be beneficial if this procedure involved a sensory branch of axillary nerve block or was performed at the beginning of the arthroscopic procedure.

LEVEL OF EVIDENCE

Prospective, randomized, double-blinded clinical trial, Level I.

Peripheral nerve blocks for outpatient surgery: evidence-based indications

PURPOSE OF REVIEW

There has been an increasing use of peripheral nerve blocks (PNBs) in ambulatory surgery. Several recent reports have contributed to our understanding of the optimal PNB technique for specific surgical procedures in this setting. In this review, we have summarized the available literature on indications of PNBs for outpatient surgery of the upper extremity.

RECENT FINDINGS

Although many of the recent studies focus on technical aspects of PNBs, few center on evidence-based indications or their utility in the ambulatory setting. The available literature suggests that although multiple techniques have been reported for outpatient shoulder surgery, interscalene brachial plexus block (ISBPB) is currently the most preferred technique. Supraclavicular, infraclavicular, and axillary brachial plexus blocks, however, are all commonly used and effective PNBs for outpatient surgery and analgesia of the arm, forearm, and hand.

SUMMARY

ISBPB is currently the most beneficial PNB for outpatient shoulder surgery. Supraclavicular block functionally can be considered an alternative to the traditional ISBPB; however, additional studies are required before routine use can be recommended. Although the review identified several reports with benefits of one PNB technique over the others, the existing literature suggests that many of these techniques may be interchangeable with regards to procedures of the distal upper extremity. Future studies are indicated to help standardize the techniques, selection, and postoperative management of PNBs for specific surgical indications.

Analgesic effectiveness of nerve block in shoulder arthroscopy: comparison between interscalene, suprascapular and axillary nerve blocks

PURPOSE

Postoperative pain in arthroscopic shoulder surgery cannot be easily controlled with analgesics and nerve blocks. This study shows the analgesic effect of interscalene block (ISB) and suprascapular nerve block and axillary nerve block (SSNB + ANB) in patients under patient controlled analgesia (PCA).

METHODS

Sixty-one patients (26 men and 35 women) who underwent arthroscopic rotator cuff repair were selected and allocated non-randomly to one of three groups: PCA only-group, PCA with ISB-group and PCA with SSNB + ANB-group. Visual analogue scale (VAS) score, degree of satisfaction, PCA usage and incidence of nausea and vomiting were evaluated at the recovery room, 8, 16 and 24 postoperative hours.

RESULTS

The VAS score of the PCA only-group was highest at the recovery room. The VAS score of the PCA with ISB-group was the lowest, however, with large fluctuations over time. Although the VAS score of the PCA with SSNB + ANB-group was higher than that of the PCA with ISB-group, it was steadily lower than the PCA-only group, without any fluctuations. The degree of satisfaction of the PCA with ISB-group was highest at the recovery room. The number of times the PCA was used at the 8-h postoperative evaluation was largest in the PCA only-group.

CONCLUSIONS

The initial 24 h after surgery plays a key role in controlling pain after arthroscopic shoulder surgery. PCA with SSNB + ANB is a better anaesthetic choice than PCA with ISB or PCA only during the initial 24 h of the postoperative period.

LEVEL OF EVIDENCE

Clinical study, Level II.

Suprascapular nerve block: a narrative review

Suprascapular nerve blockade (SSNB) is a simple and safe technique for providing relief from various types of shoulder pain, including rheumatologic disorders, cancer, and trauma pain, and postoperative pain due to shoulder arthroscopy. Posterior, superior, and anterior approaches may be used, the most common being the posterior. Recently, an ultrasound-guided approach has been described. In this review, the basic anatomy of the suprascapular nerve will be described. The different techniques of SSNB and indications for SSNB will be discussed. The complications of SSNB and outcomes of SSNB on the management of acute and chronic shoulder pain will be reviewed.

Regional blockade of the shoulder: approaches and outcomes

The article reviews the current literature regarding shoulder anesthesia and analgesia. Techniques and outcomes are presented that summarize our present understanding of regional anesthesia for the shoulder. Shoulder procedures producing mild to moderate pain may be managed with a single-injection interscalene block. However, studies support that moderate to severe pain, lasting for several days is best managed with a continuous interscalene block. This may cause increased extremity numbness, but will provide greater analgesia, reduce supplemental opioid consumption, improve sleep quality and patient satisfaction. In comparison to the nerve stimulation technique, ultrasound can reduce the volume of local anesthetic needed to produce an effective interscalene block. However, it has not been shown that ultrasound offers a definitive benefit in preventing major complications. The evidence indicates that the suprascapular and/or axillary nerve blocks are not as effective as an interscalene block. However in patients who are not candidates for the interscalene block, these blocks may provide a useful alternative for short-term pain relief. There is substantial evidence showing that subacromial and intra-articular injections provide little clinical benefit for postoperative analgesia. Given that these injections may be associated with irreversible chondrotoxicity, the injections are not presently recommended.

Suprascapular neuropathy: what does the literature show?

Suprascapular neuropathy remains a rare, albeit increasingly recognized, diagnosis. Despite its relatively low prevalence, it must be kept in the shoulder surgeon's mind as a potential cause of shoulder pain, particularly in patients where the history, physical examination, and imaging studies do not adequately explain a patient's symptoms or disability. Although challenging to identify, suprascapular neuropathy can be successfully treated. The current literature shows that the location and mechanism of nerve injury are the most important factors guiding management. Different treatment strategies are required, depending on the specific location and type of nerve injury. Controversy regarding if and when to perform an isolated suprascapular nerve release continues. Furthermore, no recommendations regarding suprascapular nerve release in conjunction with rotator cuff repair can be made at this time, and further research is necessary to better delineate the indications in the future.

A randomized study of the effectiveness of suprascapular nerve block in patient satisfaction and outcome after arthroscopic subacromial decompression

PURPOSE

The purpose of this study was to evaluate the efficiency of the suprascapular nerve (SSN) block in pain reduction after arthroscopic subacromial decompression operations and its influence on patient satisfaction. Furthermore, we wanted to evaluate whether better perioperative pain management could positively influence postoperative shoulder function.

METHODS

In this prospective, randomized, double-blinded clinical trial, 3 groups of patients--each with 15 participants--were treated with SSN block (10 mL of 1% ropivacaine), placebo, or a subacromial infiltration of local anesthesia (20 mL of 1% ropivacaine). Preoperative and postoperative pain was evaluated with a visual analog scale. Functional outcome was measured by the Constant-Murley score, and patient satisfaction was measured anecdotally by interview 2 days, 2 weeks, and 6 weeks after surgery.

RESULTS

The SSN group reported significantly lower levels of postoperative pain, required significantly less analgesia, had better range of motion, and had higher levels of postoperative satisfaction in comparison to the subacromial infiltration group and placebo group.

CONCLUSIONS

Patients treated with SSN blocks had less pain overall, which led to a decreased need for analgesics in comparison to the subacromial infiltration and placebo groups. Furthermore, patients in the SSN-blocked group achieved better postoperative ROM and were significantly more satisfied after surgery.

An anatomic and clinical study of the suprascapular and axillary nerve blocks for shoulder arthroscopy

HYPOTHESIS

The combination of suprascapular nerve block (SSNB) and axillary nerve block (ANB) has been reported to provide safe and effective analgesia for arthroscopic shoulder surgery. This study was designed to identify anatomic landmarks of the suprascapular nerve (SSN) and axillary nerve (AN) and to evaluate the effects of SSNB and ANB using the identified landmarks.

MATERIALS AND METHODS

This study included 52 cadaveric shoulders and 30 patients in the anatomic and clinical studies, respectively. After the exact location of the SSN and AN was identified from the cadavers, the clinical study at the end of the operation and at 8, 16, 24, 32, 40, and 48 hours postoperatively was performed in 2 groups: without both SSNB and ANB (group I) and with both SSNB and ANB (group II).

RESULTS

The SSN was located at a length of one-half (2/5-3/5, 88%) from the anterior tip of the acromion to the superior angle of the scapula and at a length of two-fifths (1/3-1/2, 100%) from the anterior tip of the acromion to the medial border of the spine. The AN was located at a length of three-fifths (2/5-4/5, 98%) from the acromial angle to the inferior insertion of the teres major muscle. The depth from the skin was 3.20 ± 0.58 cm for the SSN and 2.07 ± 0.45 cm for the AN. The clinical study showed that the total amount of analgesic for patient-controlled anesthesia was markedly decreased at the end of the operation and at 8 hours postoperatively in group II compared with group I.

CONCLUSIONS

The SSNB and ANB were considered to provide safe and effective analgesia in terms of early postoperative pain in arthroscopic shoulder surgery.

Suprascapular neuropathy in a shoulder referral practice

HYPOTHESIS

Suprascapular neuropathy (SSN) is considered a rare condition, and few studies have analyzed how commonly it is encountered in practice. Electrophysiologic studies are the gold standard for diagnosis; however, there is no consensus on diagnostic criteria. We hypothesized that SSN would be frequently diagnosed by electrophysiologic testing in a subset of patients with specific clinical and radiographic findings suggestive of the pathology. This study characterizes SSN in an academic shoulder referral practice and documents the electrodiagnostic findings that are currently being used to diagnose the condition.

MATERIALS AND METHODS

A retrospective review of a 1-year period was used to identify all patients who completed electrodiagnostic studies to evaluate the suprascapular nerve. Clinical exam findings and associated shoulder pathology was documented. The specific electromyography (EMG) and nerve conduction studies (NCS) findings were analyzed.

RESULTS

Electrodiagnostic results were available for 92 patients, and 40 (42%) had confirmed SSN. Patients with a massive rotator cuff tear were more likely to have an abnormal study than those without a tear (P = .006). The most common electrodiagnostic abnormalities were abnormal motor unit action potentials (88%), whereas only 33% had evidence of denervation. The average latency in studies reported as diagnostic of SSN was 2.90 ± 0.08 milliseconds for the supraspinatus and 3.78 ± 0.14 milliseconds for the infraspinatus.

DISCUSSION

An electrodiagnostically confirmed diagnosis of SSN was seen in 4.3% of all new patients and in 43% of patients with clinical or radiographic suspicion of SSN. Clinical evaluation may be difficult because other shoulder pathology can have overlapping symptoms.

CONCLUSION

Shoulder surgeons should consider electrophysiologic evaluation of patients with clinical or radiographic signs of SSN and be cognizant of the parameters that constitute an abnormal study.

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