Neurologic Sequelae After Interscalene Brachial Plexus Block for Shoulder/Upper Arm Surgery: The Association of Patient, Anesthetic, and Surgical Factors to the Incidence and Clinical Course

Complication rates and efficacy of single-injection vs. continuous interscalene nerve block: a prospective evaluation following arthroscopic primary rotator cuff repair without a concomitant open procedure

Background

To compare the complications and efficacy of pain relief of the interscalene anesthetic block using either a single-injection (SI) vs. a continuous, indwelling catheter (CIC) for arthroscopic rotator cuff repair surgery.

Methods

Patients undergoing primary, arthroscopic rotator cuff repair without concomitant open procedure or biceps tenodesis were prospectively enrolled by 4 fellowship-trained sports medicine and shoulder surgeons. Patients received either a SI or CIC preoperatively based on surgeon preference. Patients were contacted by phone to complete a standard questionnaire on postoperative days (PODs) 1, 3, 7, 14, and 28. Patients were asked to rate the efficacy of their subjective pain relief (scale of 0-10), document issues with the catheter, describe analgesic usage, and report pharmacological and medical complications. The primary outcome was measured as complication rate. Postoperative narcotic use, patient satisfaction, and visual analog scale pain scores were measured as secondary outcomes.

Results

Seventy patients were enrolled, 33 CIC patients (13 male, 20 female, mean age 61 ± 8 years) and 37 SI patients (20 male, 17 female, mean age 59 ± 10 years). There were significantly more injection/insertion site complications in the CIC group (48%) vs. the SI group (11%, P = .001). The incidence of motor weakness was higher in the CIC group on POD 1 (P = .034), but not at any subsequent time points. On POD 1, CIC patients had a clinically significantly lower pain score compared to SI (3.2 vs. 5.4; P = .020). Similar scores were observed at subsequent time points until POD 28, when CIC again had a lower pain score (0.8 vs. 2.7; P = .005). However, this did not reach clinical significance. All patients in both groups rated a satisfaction of 9 or 10 (scale 0-10) with the anesthesia provided by their nerve block.

Conclusion

CIC interscalene nerve blocks had an increased risk for injection site complications and minor complications in the immediate postoperative period when using the CIC for arthroscopic rotator cuff repair without any concomitant open procedures. CIC blocks demonstrated clinically significant superior pain relief on POD 1 but were equal to SI blocks at every time point thereafter. Superior pain relief of CIC at POD 28 was not clinically significant. CIC catheters do not appear to markedly decrease the use of postoperative narcotics. Despite this trend in complication rates and pain scores, all patients in both groups were satisfied with their nerve block.

Neurological injury following peripheral nerve blocks: a narrative review of estimates of risks and the influence of ultrasound guidance

BACKGROUND

Peripheral nerve injury or post-block neurological dysfunction (PBND) are uncommon but a recognized complications of peripheral nerve blocks (PNB). A broad range of its incidence is noted in the literature and hence a critical appraisal of its occurrence is needed.

OBJECTIVE

In this review, we wanted to know the pooled estimates of PBND and further, determine its pooled estimates following various PNB over time. Additionally, we also sought to estimate the incidence of PBND with or without US guidance.

EVIDENCE REVIEW

A literature search was conducted in six databases. For the purposes of the review, we defined PBND as any new-onset sensorimotor disturbances in the distribution of the performed PNB either attributable to the PNB (when reported) or reported in the context of the PNB (when association with a PNB was not mentioned). Both prospective and retrospective studies which provided incidence of PBND at timepoints of interest (>48 hours to <2 weeks; >2 weeks to 6 weeks, 7 weeks to 5 months, 6 months to 1 year and >1 year durations) were included for review. Incidence data were used to provide pooled estimates (with 95% CI) of PBND at these time periods. Similar estimates were obtained to know the incidence of PBND with or without the use of US guidance. Additionally, PBND associated with individual PNB were obtained in a similar fashion with upper and lower limb PNB classified based on the anatomical location of needle insertion.

FINDINGS

The overall incidence of PBND decreased with time, with the incidence being approximately 1% at <2 weeks' time (Incidence per thousand (95% CI)= 9 (8; to 11)) to approximately 3/10 000 at 1 year (Incidence per thousand (95% CI)= 0. 3 (0.1; to 0.5)). Incidence of PBND differed for individual PNB with the highest incidence noted for interscalene block.

CONCLUSIONS

Our review adds information to existing literature that the neurological complications are rarer but seem to display a higher incidence for some blocks more than others. Use of US guidance may be associated with a lower incidence of PBND especially in those PNBs reporting a higher pooled estimates. Future studies need to standardize the reporting of PBND at various timepoints and its association to PNB.

Neuropathies Following an Ultrasound-Guided Axillary Brachial Plexus Block

Purpose

Ultrasound-guided brachial plexus block (UGBPB) has interscalene, supraclavicular, infraclavicular, and axillary approaches. The axillary block is considered to be the safest and with fewer adverse events compared to the interscalene (eg, phrenic nerve block, spinal cord or vertebral artery puncture) and supraclavicular (eg, pneumothorax). However, with regard to postoperative neurological symptoms (PONS), it is controversial whether its incidence after an axillary block was higher than that after non-axillary approaches". In this study, we investigated whether the incidence of a neuropathy after an axillary block was higher than that after non-axillary approaches.

Patients and Methods

This was a single-center, retrospective cohort study. All UGBPBs were performed under general anesthesia between January 2014 and March 2020. The outcomes included the overall incidence of PONS and neuropathies for axillary and non-axillary approaches. The etiology, symptoms, and outcomes of patients were investigated.

Results

Of the 992 patients, 143 (14%) and 849 (86%) were subjected to axillary and non-axillary approaches, respectively. Among 19 cases (19.2:1000; 95% confidence interval [CI], 18.2-20.1) of PONS, four (4.0:1000; 95% CI, 3.8-4.2) were neuropathies attributed to the UGBPB, three (21.0:1000; 95% CI, 18.1-23.8) to the axillary and one (2.8:1000; 95% CI, 2.6-3.1) to non-axillary approaches. The incidence of neuropathies after an axillary block was significantly higher than that after non-axillary approaches (P = 0.005).

Conclusion

The incidence of neuropathies after US-guided axillary block under general anesthesia was significantly higher than that after non-axillary approaches.

Multimodal Approach in Minimizing Transient Neurological Complications Following Single Shot Brachial Plexus Block: A Prospective Observational Study

PURPOSE

The aim of the study was to assess the benefit of a using multimodal approach, including injection pressure monitoring (IPM) and different techniques of nerve localization, with respect to complications following single-shot brachial plexus block (SSBPB).

METHODS

In this study, 238 adults (132 males and 106 females) undergoing upper-limb surgeries under peripheral nerve block (PNB) were evaluated. Of these, 198 patients were given supraclavicular block, and 40 patients received interscalene block using either ultrasound (USG) and peripheral nerve stimulation (PNS) or PNS alone. Injection pressure monitoring was used in 216 patients.

RESULTS

Transient neurological deficit (TND) was observed in six out of 198 patients where USG and NS were used along with IPM as opposed to 12 out of 18 patients without IPM (p<0.0001). In patients where only PNS was used, transient neurological deficit (TND) was seen in six out of 18 patients with IPM as opposed to all the patients (n=4) without IPM (p<0.02). Among the patients where injection pressure was monitored, six out of 198 patients developed TND when both USG and NS were used, compared to six out of 18 patients where only PNS was used (p<0.007).

CONCLUSION

Use of injection pressure monitoring along with different nerve localization techniques results in fewer transient neurological deficits.

Peripheral Nerve Injury After Upper-Extremity Surgery Performed Under Regional Anesthesia: A Systematic Review

Purpose

Peripheral nerve injury (PNI) is a known adverse event following upper-limb surgery performed under brachial plexus regional anesthesia (RA). When PNI is noted after surgery, patients and providers often have questions about which factors might have contributed to this complication. This systematic review evaluates the literature on hand and shoulder surgeries performed under ultrasound-guided, plexus RA to identify factors potentially associated with PNI, including the surgery location and block type. We hypothesized that shoulder surgery might be associated with an increased risk of PNI compared to hand surgery.

Methods

A systematic review of the relevant literature was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Only prospective studies on the use of ultrasound-guided, preoperative, brachial plexus RA for hand or shoulder surgery on adult patients were included. Study groups were categorized according to surgery location and block type and compared across a number of factors via univariate and multivariate analyses.

Results

A total of 3,037 abstracts were screened; 192 full-text articles were independently reviewed by 2 of the authors; and 53 studies were included in the systematic review analysis. Following hand surgery, PNI was reported at an average rate of 1.35% ± 3.21% across 836 subjects in 40 study groups; after shoulder surgery, the average rate was 0.50% ± 1.57% across 3,383 subjects in 15 study groups. There was no statistically significant correlation between the incidence of PNI and surgery location (P =.70) or any of the most common approaches for brachial plexus anesthesia in the multivariate analysis.

Conclusions

This systematic review of over 50 articles on upper-limb surgery performed under RA shows no association between the incidence of PNI and the location of surgery or type of brachial plexus block.

Type of study/level of evidence

Diagnostic II.

Postoperative neurologic symptoms in the operative arm after shoulder surgery with interscalene blockade: a systematic review

OBJECTIVE

Postoperative neurologic symptoms (PONS) in the operative arm are important complications of shoulder surgery and interscalene blockade (ISB). This systematic review aimed to compare the risk of PONS between ISB and other techniques, and the relative safety of different agents used in ISB.

METHODS

Our systematic review followed Cochrane review methodology and was registered in PROSPERO. A search of MEDLINE (Ovid), EMBASE (Ovid), and CENTRAL (Wiley) from inception to June 2020 was completed. We included randomized or quasi-randomized trials of patients (> five years old) undergoing shoulder surgery with any ISB technique as an intervention, compared with any other nonregional or regional technique, or ISB of alternate composition or technique. The primary outcome was PONS (study author defined) assessed a minimum of one week after surgery.

RESULTS

Fifty-five studies totalling 6,236 participants (median, 69; range, 30-910) were included. Another 422 otherwise eligible trials were excluded because PONS was not reported. Heterogeneity in when PONS was assessed (from one week to one year) and the diagnostic criteria used precluded quantitative meta-analysis. The most common PONS definition, consisting of one or more of paresthesia, sensory deficit, or motor deficit, was only used in 16/55 (29%) trials. Risk of bias was low in 5/55 (9%) trials and high in 36/55 (65%) trials, further limiting any inferences.

CONCLUSION

These findings highlight the need for a standardized PONS outcome definition and follow-up time, along with routine, rigorous measurement of PONS in trials of ISB.

STUDY REGISTRATION

PROSPERO (CRD42020148496); registered 10 February 2020.

Initiation Timing of Continuous Interscalene Brachial Plexus Blocks in Patients Undergoing Shoulder Arthroplasty: A Retrospective Before-and-After Study

A continuous interscalene brachial plexus block (CIBPB) is usually administered before surgery in awake patients. However, the use of CIBPB before surgery could hinder the identification of nerve injuries after total shoulder arthroplasty (TSA). This study aimed to compare the analgesic effects of preoperatively and postoperatively initiated CIBPBs in patients undergoing TSA. The medical records of patients who underwent TSA between January 2016 and August 2020 were retrospectively reviewed. The following analgesic phases were used: intravenous (IV) patient-controlled analgesia (PCA) phase (IV PCA group, n = 40), preoperative block phase (PreBlock group, n = 44), and postoperative block phase (PostBlock group, n = 33). The postoperative initiation of CIBPB after a neurologic exam provided better analgesia than IV PCA and had no differences with the preoperative initiation of CIBPB, except for the worst pain at the postanesthetic care unit. Opioid consumption was significantly greater in the IV PCA group, but there were no differences between the PreBlock and PostBlock groups on operation day after the transfer to the general ward. The initiation of CIBPB after a patient’s emergence from general anesthesia had comparable analgesic efficacy with preoperative CIBPB but offered the chance of a postoperative neurologic exam.

Perioperative Oral Pregabalin Results in Postoperative Pain Scores Equivalent to Those of Interscalene Brachial Plexus Block After Arthroscopic Rotator Cuff Repair: A Randomized Clinical Trial

PURPOSE

To compare the analgesic effects of pregabalin to those of single-shot interscalene brachial plexus block (ISBPB) in adults having arthroscopic rotator cuff (RC) repair, as well as ISBPB's effect on postoperative opioid consumption, patient satisfaction, and opioid-related adverse effects.

METHODS

In this randomized trial, 79 adults having arthroscopic RC repair were randomized to receive perioperative oral pregabalin (Lyrica, twice daily starting the evening before surgery, for a total of 4 doses) or single-shot ISBPB (20 ml of bupivacaine 0.25%). Intra- and postoperative management was standardized. The primary outcome was median self-reported pain score (on a visual analog scale of 0 to 100) at rest during the initial 10 postoperative days. Other outcomes included pain during activity, postoperative opioid consumption, opioid-related adverse effects, quality of recovery, and pain satisfaction score.

RESULTS

Of 71 eligible patients, 59 were analyzed, of whom 29 received pregabalin and 30 received ISBPB. Groups were similar regarding demographic, baseline, and intraoperative variables. Median pain score at rest over the 10 postoperative days was 51 (interquartile range 26, 76) in the pregabalin group and 52 (22, 74) in the ISBPB group (difference 0.5 points; 95% confidence interval [CI] -3.2 to 6.3; P = .53). Opioid consumption during the initial 10 postoperative days was also similar (difference in median 90 mg of morphine equivalents; 95% CI -32 to 177.5; P = .12). No differences were found in any other outcome.

CONCLUSIONS

Perioperative use of pregabalin in adults undergoing arthroscopic RC repair provided analgesia comparable to that of ISBPB for 10 days after surgery.

LEVEL OF EVIDENCE

II, randomized controlled trial (high dropout rate).

Ensuring the effectiveness and safety of peripheral blockades

Adequate analgesia determines the success of the performed surgical intervention. In modern surgery, most of postoperative complications are directly related to ineffective therapy of pain syndrome in the perioperative period. The main principle of modern analgesia is its multicomponence, when analgesia, neurovegetative blockade and relaxation are achieved and potentiated by different drugs and methods. The blockade of nociceptive impulses with a local anesthetic at the transmission stage provides effective, targeted analgesia, hyporefl exia and muscle relaxation, prevents the sensitization of neuroaxial structures, hyperalgesia and the development of postoperative chronic pain syndrome. At the same time, providing analgesia with drugs of central action leads to the ineffectiveness of therapy in 80 % of cases, which has serious consequences.The aim. According to the literature review, to evaluate the effectiveness and safety of peripheral blockades on the example of performing a blockade of the pterygopalatine ganglion.Conclusion. The pterygopalatine blockade has broad indications for use in ophthalmology, which is explained by the complex structure of the pterygopalatine ganglion and the possibility of simultaneous infl uence on sympathetic, parasympathetic and nociceptive innervation. All the presented methods of pterygopalatine blockade performance have their advantages and disadvantages. Ultrasound navigation eliminates technical difficulties and the possibility of damage of the pterygopalatine fossa anatomical structures, ensuring the effectiveness and safety of the pterygopalatine blockade.

Erector spinae plane block vs. peri-articular injection for pain control after arthroscopic shoulder surgery: a randomised controlled trial

Interscalene brachial plexus block is the standard regional analgesic technique for shoulder surgery. Given its adverse effects, alternative techniques have been explored. Reports suggest that the erector spinae plane block may potentially provide effective analgesia following shoulder surgery. However, its analgesic efficacy for shoulder surgery compared with placebo or local anaesthetic infiltration has never been established. We conducted a randomised controlled trial to compare the analgesic efficacy of pre-operative T2 erector spinae plane block with peri-articular infiltration at the end of surgery. Sixty-two patients undergoing arthroscopic shoulder repair were randomly assigned to receive active erector spinae plane block with saline peri-articular injection (n = 31) or active peri-articular injection with saline erector spinae plane block (n = 31) in a blinded double-dummy design. Primary outcome was resting pain score in recovery. Secondary outcomes included pain scores with movement; opioid use; patient satisfaction; adverse effects in hospital; and outcomes at 24 h and 1 month. There was no difference in pain scores in recovery, with a median difference (95%CI) of 0.6 (-1.9-3.1), p = 0.65. Median postoperative oral morphine equivalent utilisation was significantly higher in the erector spinae plane group (21 mg vs. 12 mg; p = 0.028). Itching was observed in 10% of patients who received erector spinae plane block and there was no difference in the incidence of significant nausea and vomiting. Patient satisfaction scores, and pain scores and opioid use at 24 h were similar. At 1 month, six (peri-articular injection) and eight (erector spinae plane block) patients reported persistent pain. Erector spinae plane block was not superior to peri-articular injection for arthroscopic shoulder surgery.

Isolated Anterior Interosseous Neuropathy Affecting Only the Flexor Digitorum Profundus to the Index Finger After Shoulder Arthroscopy: A Case Report and Review of the Literature

ABSTRACT

Anterior interosseous nerve neuropathy is an uncommon neuropathy with multiple potential etiologies. We present a rare case of anterior interosseous nerve neuropathy affecting only the flexor digitorum profundus to the index finger and occurring after shoulder arthroscopy. This unique presentation used a combination of both electrodiagnostic testing and neuromuscular ultrasound to obtain an accurate diagnosis and highlights the importance of these complementary tests in the evaluation of nerve disorders. To our knowledge, anterior interosseous nerve neuropathy after shoulder arthroscopy affecting only the flexor digitorum profundus to the index finger has not been previously described in the literature.

Effects of prolonged peri-neural bupivacaine infusion in rat sciatic nerves (axon and myelin)

BACKGROUND/OBJECTIVE

Peripheral-nerve blocks (PNBs) using continuous-infusion of local anesthetics are used to provide perioperative analgesia. Yet little research exists to characterize the histopathological effects of continuous long-duration PNBs. Herein we test the hypothesis that continuous peri-neural bupivacaine infusion (3-day vs. 7-day infusion) contributes to histologic injury in a duration-dependent manner using an in vivo model of rat sciatic nerves.

METHODS

We placed indwelling catheters in 22 rats for infusion with low-dose (0.5mg/kg/hr) bupivacaine or normal saline proximal to the right sciatic nerves for 3 or 7 consecutive days. Hind-limb analgesia was measured using Von-Frey nociceptive testing. At infusion end, rats were sacrificed, bilateral nerves were sectioned and stained with hematoxylin and eosin and CD68 for evaluation of inflammatory response, and eriochrome to assess damage to myelin.

RESULTS

Animals receiving continuous infusion of bupivacaine maintained analgesia as demonstrated by significant decrease (50% on average) in nociceptive response in bupivacaine-infused limbs across time points. Both 7-day saline and bupivacaine-infused sciatic nerves showed significantly-increased inflammation by H&E staining compared to untreated native nerve controls (P = 0.0001, P < 0.0001). Extent of inflammation did not vary significantly based on infusate (7-day saline vs. 7-day bupivacaine P > 0.99) or duration (3-day bupivacaine vs 7-day bupivacaine P > 0.99). No significant change in sciatic nerve myelin was found in bupivacaine-infused animals compared to saline-infused controls, regardless of duration.

CONCLUSIONS

Long-duration (7-day) bupivacaine infusion provided durable post-operative analgesia, yet contributed to equivalent neural inflammation as short duration (3-day) infusion of bupivacaine or saline with no evidence of demyelination.

Postoperative neurological complications after brachial plexus block: a retrospective study conducted at a teaching hospital

PURPOSE

Serious complications after ultrasound-guided regional anaesthesia can be devastating for the patient. The pathogenesis of postoperative neurological complications (PONC) is multifactorial and includes mechanical, vascular and chemical factors besides the nerve puncture itself. The primary aim of this study was to assess the incidence of PONC after brachial plexus block (BPB).

METHODS

This is an observational retrospective single-centre study conducted at the regional anaesthesia unit of a teaching hospital. All BPBs performed from January 2011 to November 2019 were included. The outcomes analysed were the incidence, aetiology and diagnosis of PONCs and the incidence of other postoperative complications such as local anaesthetic systemic toxicity (LAST), pneumothorax, wrong-side block, etc. The performance of trainees and experienced anaesthesiologists was compared across all the outcomes.

RESULTS

From a total of 5340 BPBs included, 15 cases developed PONC, yielding a rate of 2.81:1000 (95% CI 1.70-4.63). Thirteen patients underwent neurophysiological exams which confirmed nine neuropathies. The rate of PONCs for supervised trainees was 1.80:1000 (95% CI 0.701-4.62), not statistically different from that of experienced anaesthesiologists (p = 0.241). Three cases were considered to present with a PONC probably related to BPB [0.562:1,00 (95% CI 0.191-1.65)]. The incidence of long-term PONCs was 1.12:1000 (95% CI 0.515-2.45). Such complications proved irreversible in 2 cases. The incidences of LAST, pneumothorax and other complications observed were 0.749:1000 (95% CI 0.291-1.92), 0.187:1000 (95% CI 0.0331-1.06) and 4.31:1000 (95% CI 2.87-6.46), respectively.

CONCLUSIONS

This survey suggests that complications after ultrasound-guided BPB, including blocks performed by trainees, are uncommon.

TRIAL REGISTRATION

Clinicaltrials.gov ID: NCT04451642.

Perioperative anaesthetic considerations for rotator cuff repair surgeries: A current concept review

Surgeries for Rotator Cuff (RC) pathologies are required for either trauma or degenerative related aetiologies. Various surgical techniques from open to arthroscopic repair, are being undertaken by orthopaedic surgeons. Peri-operative anaesthetic management of the patients undergoing rotator cuff repair requires understanding the surgical procedure and patient status for optimal anaesthetic planning. Such management mandates a thorough pre-operative evaluation, including clinical history, examination, and relevant investigations. Patients with acute trauma associated Rotator Cuff (RC) tears should be assessed for visceral injuries using appropriate injury evaluation systems before such repairs. On the other hand, patients with degenerative tears tend to be older with associated comorbidities. Hence pre-operative optimisation is necessary according to risk stratification. Anaesthetic techniques for Rotator Cuff (RC) surgery include general anaesthesia or regional anaesthesia. These are individualised according to patient assessment and surgical procedure planned. Knowledge of relevant surgical anatomy is essential for intra-operative, and post-operative neural blockade techniques since optimal peri-operative analgesia improve overall patient recovery. The occurrence of a peri-operative complication should be recognised as timely management improves the patient-related surgical outcomes. We describe the relevance of surgical anatomy, the effect of patient positioning, irrigating fluids, various anaesthetic techniques and an overview of regional and medical interventions to manage pain in patients undergoing for Rotator Cuff (RC) surgery.

Anterior Interosseous Nerve Palsy After Shoulder Arthroscopy Treated With Surgical Decompression: A Case Series and Systematic Review of the Literature

Background: Anterior interosseous nerve (AIN) palsy is a very uncommon cause of upper extremity pain and weakness that comprises less than 1% of all upper extremity nerve palsies. Rarely reported but also mentioned in the literature is AIN palsy after shoulder arthroscopy. Methods: A systematic review of the literature to date using PubMed was conducted to identify patients who suffered AIN palsy after shoulder arthroscopy procedures. Articles included met the following criteria: (1) published in English; (2) primary presentation of the data; (3) patients had undergone shoulder arthroscopy before developing symptoms of AIN palsy; and (4) diagnosis was confirmed with clinical symptoms of AIN palsy. Measured outcomes included patient demographics, specific shoulder procedure, anesthesia procedure, intra-operative patient positioning, intra-operative compressive dressing, intra-operative traction, surgical versus conservative treatment, abnormal findings during decompression procedure, proposed mechanism of injury, and follow-up. Results: The search yielded 6 articles, of which 4 (13 cases) met inclusion criteria. An additional 2 cases were included in this report totaling 15 cases. The average patient age was 49 years (range: 31-64) with 73% males. At average follow-up of 24 months, 67% of patients experienced complete resolution of symptoms-more than half of which underwent surgical decompression. Patients who failed to progress experienced weakness of the flexor digitorum profundus and flexor pollicis longus muscles. Conclusions: Proposed injury mechanisms for AIN palsy after shoulder arthroscopy range from mechanical trauma, compressive hematoma, and direct anesthetic neurotoxicity. Management should be directed by clinical symptoms, imaging, and patient factors with majority of patients expected to have excellent clinical outcomes.

Comparison of Analgesic Efficacy of Ultrasound-Guided Interscalene Block Versus Continuous Subacromial Infusion for Postoperative Analgesia Following Arthroscopic Rotator Cuff Repair Surgeries: A Randomized Trial

Background: Arthroscopic rotator cuff repair surgery may lead to significant postoperative pain. Interscalene block (ISB) is an effective analgesic technique in these surgeries but there is a risk of the phrenic blockade. Subacromial local anesthetic infiltration is a phrenic sparing alternative technique for postoperative analgesia. The primary aim of our study was to compare the ISB with a continuous subacromial infusion (SAC) with regard to postoperative analgesia.

Methods: This prospective randomized, interventional parallel arm trial was conducted in 60 ASA grade I and II, adult patients (30 patients in each group) posted for arthroscopic rotator cuff repair surgery. Patients were randomly assigned to receive either ultrasound-guided ISB (Group ISB: 15 ml of 0.75% ropivacaine) or continuous SAC (Group SAC: 15 ml 0.75% ropivacaine as a subacromial injection by ultrasound guidance and infusion of 3 ml/hour of 0.5% ropivacaine through the catheter placed subacromial by the surgeon). Intraoperative hemodynamic parameters, visual analog scores (VAS), and rescue analgesic requirements for 24 hours, patient satisfaction, and complications were recorded.

Results: Rescue analgesic requirement was significantly higher in SAC at zero hours (P=0.000), while it was significantly higher in ISB at 12 hours (P=0.02). The VAS scores were comparable at all time points and patient satisfaction at 24 hours was similar. None of the patients had rated satisfaction related to pain relief as poor in any group. Complications like ptosis and motor weakness were seen only with ISB.

Conclusion: Both the techniques provided effective analgesia and comparable patient satisfaction with lesser incidence of complications in the SAC group. ISB provided more effective immediate postoperative pain relief while SAC was more effective in delayed analgesia for arthroscopic rotator cuff repair surgeries. SAC can be considered a reasonably safe alternative to ISB in patients with contraindications to the latter.

Permanent hemidiaphragmatic paresis after interscalene brachial plexus block: a case report

Interscalene brachial plexus block has been widely used in shoulder surgery. We report one case of long-term phrenic palsy following ultrasound-guided interscalene brachial plexus block and we will discuss the possible etiology and mechanism of this disability. For painful shoulder surgery, ultrasound-guided interscalene brachial plexus block remains topical. Alternative blocks, such as suprascapular and axillary blocks, may be reserved for patients with pre-existing respiratory pathology.

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.

Adjacent intact nociceptive neurons drive the acute outburst of pain following peripheral axotomy

Injury of peripheral nerves may quickly induce severe pain, but the mechanism remains obscure. We observed a rapid onset of spontaneous pain and evoked pain hypersensitivity after acute transection of the L5 spinal nerve (SNT) in awake rats. The outburst of pain was associated with a rapid development of spontaneous activities and hyperexcitability of nociceptive neurons in the adjacent uninjured L4 dorsal root ganglion (DRG), as revealed by both in vivo electrophysiological recording and high-throughput calcium imaging in vivo. Transection of the L4 dorsal root or intrathecal infusion of aminobutyrate aminotransferase inhibitor attenuated the spontaneous activity, suggesting that retrograde signals from the spinal cord may contribute to the sensitization of L4 DRG neurons after L5 SNT. Electrical stimulation of low-threshold afferents proximal to the axotomized L5 spinal nerve attenuated the spontaneous activities in L4 DRG and pain behavior. These findings suggest that peripheral axotomy may quickly induce hyperexcitability of uninjured nociceptors in the adjacent DRG that drives an outburst of pain.

The Ultrasound Anatomy of Nerves in the Interscalene Groove: Can We Reliably Distinguish the Nerve Structures for Needle Placement During Nerve Blocks?

In the interscalene groove, nerve structures are in close proximity and may not be visible as separate structures, increasing the risk of insertion of the needle tip within the epineurium. We evaluated whether experienced regional anesthesiologists can distinguish between nerve elements lying in close proximity on ultrasound images.Brachial plexus elements from 4 nonpreserved cadavers were arranged in a water bath. Ultrasound images of the nerve roots and trunks were taken. Regional anesthesiologists and residents were asked whether they could distinguish the nerves as 2 separate structures and if they could identify a pair of nerve roots versus a single trunk.Attending anesthesiologists reported the ability to discriminate 2 nerve structures when a 2-mm space was arranged between them in 54% of images; however, when in direct contact, this recognition was significantly lower. The residents reported a higher ability to discriminate the 2 nerves in all scenarios. In addition, the attending anesthesiologists successfully identified paired nerve roots versus nerve trunks in 70% of the images, significantly higher than chance (P = 0.01), whereas the fraction of correct resident responses was not significantly different from guessing.When nerves were placed in close proximity, experienced regional anesthesiologists had difficulty identifying them as separate structures and were incorrect nearly one-third of the time in discriminating 2 closely positioned roots versus a nerve trunk. This underscores the importance of cautious needle insertion into the interscalene groove, where nerve elements are often juxtaposed one to another.

Long-Term Neurological Complications Associated with Surgery and Peripheral Nerve Blockade: Outcomes after 1065 Consecutive Blocks

Peripheral nerve blockade is gaining popularity as an analgesic option for both upper or lower limb surgery. Published evidence supports the improved efficacy of regional techniques when compared to conventional opioid analgesia. The incidence of neurological deficit after surgery associated with peripheral nerve block is unclear. This paper reports on neurological outcomes occurring after 1065 consecutive peripheral nerve blocks over a one-year period from a single institution. All patients receiving peripheral nerve blocks for surgery were prospectively followed for up to 12 months to determine the incidence and probable cause of any persistent neurological deficit. Formal independent neurological review and testing was undertaken as indicated. Thirteen patients reported symptoms that warranted further investigation. A variety of probable causes were identified, with peripheral nerve block being implicated in two cases (one resolved at nine months and one remaining persistent). Overall incidence of block-related neuropathy was 0.22%.

Persistent postoperative neuropathy is a rare but serious complication of surgery associated with peripheral nerve block. Formal follow-up of all such blocks is recommended to assess causality and allow for early intervention.

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.

Peripheral Nerve Injury Following Interscalene Blocks: A Systematic Review to Guide Orthopedic Surgeons

The purpose of this review was to determine the incidence and duration of peripheral neurologic symptoms following interscalene blocks for shoulder surgery. Three databases were reviewed for subjective and objective injuries by guidance modality and delivery method. The incidence of neurologic injuries following single site injection interscalene blocks, 3.16%, was significantly less than the 5.24% incidence for continuous catheter infusion interscalene blocks. Less than 0.51% of peripheral neurologic symptoms persisted beyond 1 year for both groups. There is a notable risk of injury following interscalene blocks by all modes of guidance and anesthetic technique, but only a small percentage of injuries persist. [Orthopedics. 2018; 41(5):e598-e606.].

Anterior Interosseous Nerve Neuropraxia Secondary to Shoulder Arthroscopy and Open Subpectoral Long Head Biceps Tenodesis

Arthroscopic rotator cuff tendon repair is a common elective procedure performed by trained orthopaedic surgeons with a relatively low complication rate. Specifically, isolated neuropraxia of the anterior interosseous nerve (AIN) is a very rare complication of shoulder arthroscopy. An analysis of peer-reviewed published literature revealed only three articles reporting a total of seven cases that describe this specific complication following standard shoulder arthroscopic procedures. This article reports on three patients diagnosed with AIN neuropraxia following routine shoulder arthroscopy done by a single surgeon within a three-year period. All three patients also underwent open biceps tenodesis immediately following completion of the arthroscopic procedures. The exact causal mechanism of AIN neuropraxia following shoulder arthroscopy with biceps tenodesis is not known. This case report reviews possible mechanisms with emphasis on specific factors that make a traction injury the most likely etiology in these cases. We critically analyze our operating room setup and patient positioning practices in light of the existing biomechanical and cadaveric research to propose changes to our standard practices that may help to reduce the incidence of this specific postoperative complication in patients undergoing elective shoulder arthroscopy with biceps tenodesis.

Suprascapular block associated with supraclavicular block: An alternative to isolated interscalene block for analgesia in shoulder instability surgery?

BACKGROUND

Interscalene brachial plexus block (ISB) is the gold standard for postoperative pain management in shoulder surgery. However, this technique has side effects and potentially serious complications. The aim of this study was to compare the combinations of ultrasound-guided suprascapular (SSB) associated with supraclavicular nerve block (SCB) and ultrasound-guided ISB for postoperative analgesia after shoulder instability surgery.

METHODS

Sixty ASA physical status I-II patients scheduled to undergo shoulder instability surgery were included. Two groups: (i) the SSB+SCB group (n=30) in which the patients received a combination of US-guided SSB (15mL of bupivacaine 0.25%) and US-guided SCB (15mL of bupivacaine 0.25%) and (ii) the ISB group (n=30) in which the patients received US-guided ISB with 30mL of bupivacaine 0.25%. General anesthesia was administered to all patients. During the first 24h, the variables assessed were time to administer the anesthesia, duration of the analgesia, onset and duration of motor and sensory blockade, opioid consumption, cardiovascular stability, complications, and patient satisfaction.

RESULTS

Anesthesia induction took more time for the SSB+SCB group than for the ISB group. However, the onset time of motor and sensory blockade was similar in the two groups. Statistical analysis of the visual analog postoperative pain scoring at H0, H6, H12, and H24 showed nonsignificant differences between the groups. Analgesia, the first request for morphine, and total morphine consumption during the first 24h was similar in both groups. No complication was recorded in the SSB+SCB group. However, phrenic nerve block occurred in all patients in the ISB group.

CONCLUSION

US-guided SCB combined with US-guided SSB was as effective as ISB for postoperative analgesia after shoulder instability surgery without decreasing potential side effects.

TRIAL REGISTRATION

NCT identifier: NCT02397330.

Comparison of Interscalene Brachial Plexus Block Performed With and Without Steroids

This prospective comparative clinical study was performed to evaluate the effect of triamcinolone when added to bupivacaine during brachial plexus blockade in patients undergoing shoulder surgery. Interscalene brachial plexus blocks were performed on 910 patients before shoulder surgery. Of the patients, 574 were randomly allocated to receive steroids added to the injected local anesthetic and 336 patients received local anesthetic without steroids. All patients were followed prospectively to evaluate the rate of successful anesthesia, duration of anesthesia, side effects of the block, adverse events, and persistent neurologic complications associated with interscalene brachial plexus block. Patients who received steroids had statistically longer pain relief than those who did not receive steroids (P<.001). No difference was found in adverse events, complications, or side effects. Compared with blocks performed without steroids, a statistically longer duration of block analgesia occurred with the addition of steroids to the local anesthetic solution during brachial plexus blockade. Rates of side effects, adverse events, and persistent neurologic complications were similar between the groups. [Orthopedics. 2016; 39(6):e1100-e1103.].

Mixed neuropathy presenting clinically as an anterior interosseous nerve palsy following shoulder arthroscopy: a report of four cases

BACKGROUND

Anterior interosseous nerve (AIN) palsies can arise spontaneously or be attributed to one of many causes. We present 4 cases, the largest series to date, in which a mixed peripheral neuropathy presented primarily as an AIN palsy following ipsilateral shoulder arthroscopy. In this report, we detail the patient's presenting symptoms, describe our management of the complication, and provide hypotheses for the mechanism behind the complication.

METHODS

Four different surgeons performed the initial arthroscopic surgeries, but the senior author in all cases managed follow-up and treatment of the neuropathy. All patients were informed and agreed to have their cases published.

RESULTS

All four patients experienced significant recovery, although 2 of 4 required AIN decompression and exploration because of failure to improve with conservative management.

CONCLUSION

Whereas variables such as position, index surgical procedure, and use of regional anesthesia varied among our patients, the one constant was the fluid extravasation from the arthroscopy itself, and for this reason we believe that if there is one singular cause to explain all of these neuropathies, it would be increased pressure in the upper arm and forearm from fluid extravasation in patients with at-risk anatomy. Outside of prevention, recognizing this complication and providing appropriate intervention or referral to a surgeon capable of appropriate intervention are important for any surgeon performing shoulder arthroscopies.

Neurological Complications Related to Elective Orthopedic Surgery: Part 1: Common Shoulder and Elbow Procedures

Many anesthesiologists are unfamiliar with the rate of surgical neurological complications of the shoulder and elbow procedures for which they provide local anesthetic-based anesthesia and/or analgesia. Part 1 of this narrative review series on neurological complications of elective orthopedic surgery describes the mechanisms and likelihood of peripheral nerve injury associated with some of the most common shoulder and elbow procedures, including open and arthroscopic shoulder procedures, elbow arthroscopy, and total shoulder and elbow replacement. Despite the many articles available, the overall number of studied patients is relatively low. Large prospective trials are required to establish the true incidence of neurological complications following elective shoulder and elbow surgery.

WHAT'S NEW

As the popularity of regional anesthesia increases with the development of ultrasound guidance, anesthesiologists should have a thoughtful understanding of the nerves at risk of surgical injury during elective shoulder and elbow procedures.

Efficacy of multimodal analgesia injection combined with corticosteroids after arthroscopic rotator cuff repair

INTRODUCTION

Although arthroscopic rotator cuff repair is minimally invasive, there is still considerable postoperative pain, especially during the first 48 hours. The present study assessed the short-term efficacy and safety of multimodal analgesic (MMA) injection associated to corticosteroids in arthroscopic rotator cuff tear surgery.

MATERIAL AND METHOD

A single-center prospective randomized study included 50 patients undergoing arthroscopic rotator cuff tear surgery. The study group received subacromial injection of a mixture of morphine, ropivacaine and methylprednisolone associated to intra-articular injection of morphine plus methylprednisolone; the control group received only isotonic saline. All patients had had 24 hours self-administered morphine associated to standard analgesia. Postoperative data were recorded at 30 minutes and 1, 2, 4, 6, 12, 18 and 24 hours: pain intensity, morphine intake and side effects, and also time to first morphine bolus and additional analgesic intake. Constant, ASES and SST functional scores were recorded at 3 months.

RESULTS

Postoperative pain was significantly less intense in the MMA group than in controls at 30 min, H1, H4, H6, H12, H18 and H24 (P<0.05). A rebound at D10 occurred in both groups. During the first 24 hours, MMA significantly reduced cumulative resort to morphine (P<0.05 at H1/2, P<0.001 at H1-24). Mean time to first bolus was significantly longer in the MMA group (71.6 vs. 33 min; P<0.05). The rate of opioid-related side effects was similar between groups. At last follow-up, functional scores were similar between groups. There were no cases of infection or delayed skin healing.

CONCLUSION

MMA associated to corticosteroids after arthroscopic rotator cuff tear surgery provided immediate benefit in terms of analgesia and morphine sparing, without apparent risk of infection. The practice is presently little known in France and deserves longer-term assessment, especially as regards functional rehabilitation and tendon healing.

LEVEL OF EVIDENCE

2.

Pathophysiology and Etiology of Nerve Injury Following Peripheral Nerve Blockade

This review synthesizes anatomical, anesthetic, surgical, and patient factors that may contribute to neurologic complications associated with peripheral nerve blockade. Peripheral nerves have anatomical features unique to a given location that may influence risk of injury. Peripheral nerve blockade-related peripheral nerve injury (PNI) is most severe with intrafascicular injection. Surgery and its associated requirements such as positioning and tourniquet have specific risks. Patients with preexisting neuropathy may be at an increased risk of postoperative neurologic dysfunction. Distinguishing potential causes of PNI require clinical assessment and investigation; a definitive diagnosis, however, is not always possible. Fortunately, most postoperative neurologic dysfunction appears to resolve with time, and the incidence of serious long-term nerve injury directly attributable to peripheral nerve blockade is relatively uncommon. Nonetheless, despite the use of ultrasound guidance, the risk of block-related PNI remains unchanged.

WHAT'S NEW

Since the 2008 Practice Advisory, new information has been published, furthering our understanding of the microanatomy of peripheral nerves, mechanisms of peripheral nerve injection injury, toxicity of local anesthetics, the etiology of and monitoring methods, and technologies that may decrease the risk of nerve block-related peripheral nerve injury.

Shoulder surgeons' perceptions of interscalene nerve blocks and a review of complications rates in the literature

BACKGROUND

Interscalene nerve blocks (ISBs) have been shown to be an effective option for regional anesthesia in shoulder surgery. Our study presents survey results of shoulder surgeons' perceptions of ISBs and a literature summary of complications rates with ISB use.

METHODS

A survey addressing demographics, preferences, treatment patterns, risks/benefits, and patient recommendations regarding the use of ISBs was created. Respondents were also asked whether they would elect an ISB if personally undergoing shoulder surgery, and results of other questions were stratified based on this personal preference. The survey was administered electronically to all members of the American Shoulder and Elbow Surgeons. A literature review of ISB-related complication rates was compiled from 13 studies of shoulder surgery using ISB.

RESULTS

Of all respondents, 58.7% would elect a single-shot ISB, 15.0% would elect a continuous catheter, and 26.3% would not elect the use of an ISB if undergoing shoulder surgery. Respondents from a university hospital were 1.44 times more likely to elect any ISB than respondents from a non-university hospital. Improved post-operative pain control was considered the greatest benefit, whereas persistent neuropathy was considered the greatest risk of ISB use. Of the respondents, 76.1% would recommend use of ISB to their patients undergoing shoulder surgery. Our literature review yielded 13 applicable studies that utilized a total of 6243 ISBs, with data resulting in a 0.35% major complication rate and an 11.32% minor complication rate in patients.

CONCLUSION

The majority of shoulder surgeons surveyed in our study would elect to have a single-shot interscalene nerve block if undergoing shoulder surgery themselves, indicating that ISB use is considered a safe and effective anesthetic option among shoulder surgeon specialists.

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.

Local anesthetic Schwann cell toxicity is time and concentration dependent

BACKGROUND

Peripheral nerve blocks with local anesthetics (LAs) are commonly performed to provide surgical anesthesia or postoperative analgesia. Nerve injury resulting in persistent numbness or weakness is a potentially serious complication. Local anesthetics have previously been shown to damage neuronal and Schwann cells via several mechanisms. We sought to test the hypothesis that LAs are toxic to Schwann cells and that the degree of toxicity is directly related to the concentration of LA and duration of exposure. Intraneural injection of LAs has been shown to produce nerve injury. We sought to test the hypothesis that a prolonged extraneural infusion of LA can also produce injury.

METHODS

Schwann cells cultured from neonatal rat sciatic nerves were incubated with LAs at different concentrations (10, 100, 500, and 1000 μM), and each concentration was assessed for toxicity after 4, 24, 48 and 72 hours of exposure. Local anesthetics tested were lidocaine, mepivacaine, chloroprocaine, ropivacaine, and bupivacaine. Cell death was assessed by lactate dehydrogenase release measured by optical density.In a separate experiment, a microcatheter was placed along the sciatic nerves of Sprague-Dawley rats. Rats were randomly assigned to receive either 0.9% saline (n = 8) or bupivacaine (0.5%, n = 4; 0.75%, n = 4) via the perineural catheters for 72 hours. The rats were then killed, and their nerves sectioned and stained for analysis. Sections were stained for myelin and with an antimacrophage (CD68) antibody.

RESULTS

None of the LAs tested produced significant Schwann cell death at very low concentrations (10 μM, or 0.0003%) even after prolonged exposure. With prolonged exposure (48 or 72 hrs) to high concentrations (1000 μM, or 0.03%), all of the LAs tested produced significant Schwann cell death (increased lactate dehydrogenase release relative to control as measured by optical density, 0.384-0.974; all P values < 0.001). Only bupivacaine produced significant cell death (0.482, P < 0.001) after prolonged exposure to low concentrations (100 μM, or 0.003%). At intermediate concentrations (500 μM, or 0.015%), cell death was more widespread with bupivacaine (0.768, P < 0.001) and ropivacaine (0.675, P < 0.001) than the other agents (0.204-0.368; all P values < 0.001). Prolonged extraneural exposure of rat sciatic nerves to bupivacaine caused significant demyelination and infiltration of nerves with inflammatory cells.

CONCLUSIONS

Local anesthetics induce Schwann cell death in a time- and concentration-dependent manner. Bupivacaine and ropivacaine have greater toxicity at intermediate concentrations, and prolonged exposure to bupivacaine produces significant toxicity even at low concentrations. Brief exposure to high concentrations of bupivacaine damages Schwann cells. Prolonged extraneural infusion of bupivacaine results in nerve injury.

Effect of bupivacaine concentration on the efficacy of ultrasound-guided interscalene brachial plexus block

Background:

Interscalene brachial plexus block (ISBPB) is an effective technique for shoulder surgery and postoperative pain control. The aim of this study is to compare the analgesic efficacy of 0.1% vs 0.2% bupivacaine for continuous postoperative pain control following arthroscopic shoulder surgery.

Methods:

A total of 40 adult patients divided into two groups (each 20 patients) undergoing arthroscopic shoulder surgery were randomized to receive an ultrasound-guided ISBPB of either 0.1% or 0.2% bupivacaine 10 ml bolus plus 5 ml/h infusion through interscalene catheter. Standard general anesthesia was given. Both groups received rescue postoperative PCA morphine. Pain, sensory, and motor power were assessed before for all patients, 20 minute after the block, postoperatively in the recovery room, and at 2, 6, 12, and 24 hours thereafter. The patient and surgeon satisfaction and the analgesic consumption of morphine were recorded in the first 24 hours postoperatively. A nonparametric Mann-Whitney was used to compare between the two groups for numerical rating scale, morphine consumption in different time interval.

Results:

Group 1 (0.1% bupivacaine) patients had significantly received more intraoperative fentanyl and postoperative morphine with higher pain scores at 24 hours postoperatively vs group 2 (0.2% bupivacaine) patients.

Conclusions:

The use of ultrasound-guided ISBPB with 0.2% bupivacaine provided better intra- and post-operative pain relief vs 0.1% bupivacaine in arthroscopic shoulder surgery.

A prospective analysis of interscalene brachial plexus blocks performed under general anesthesia

BACKGROUND

The purpose of this prospective study was to assess the safety and efficacy of interscalene brachial plexus block anesthesia when performed on patients who were anesthetized with a general anesthetic prior to the performance of the block.

METHODS

Patients were assessed postoperatively through surveys, interviews, and physical examinations to document block success, duration of anesthesia, block side effects, and persistent neurological complications. Nine-hundred fifty-one patients were available for the analysis.

RESULTS

The overall block success rate was 97% and the mean duration of anesthesia provided by the blocks was 23.9 hours. Immediate postoperative block side effects occurred in 16% (142 of 910), persistent neurological complications occurred in 4.4% (40 of 910) of patients, and long-term neurologic complications occurred in 0.8% (8 of 910).

CONCLUSION

Our study results suggest that the rates of success and complications associated with the performance of interscalene block regional anesthesia performed after induction of general anesthesia are similar to the results demonstrated in prior studies in which brachial plexus block was performed on nonanesthetized patients. Although significant complications were not common, this procedure is not without risk and can result in long-term neurologic complications.

A prospective clinical registry of ultrasound-guided regional anesthesia for ambulatory shoulder surgery

BACKGROUND

There is a lack of clinical registries to document efficacy and safety of ultrasound-guided regional anesthesia. Interscalene blocks are effective for shoulder arthroscopy, and ultrasound guidance may reduce risk. Furthermore, ultrasound-guided supraclavicular block is a novel approach for shoulder anesthesia that may have less risk for neurological symptoms than interscalene block.

METHODS

One thousand one hundred sixty-nine patients undergoing ultrasound-guided regional anesthesia for ambulatory shoulder arthroscopy were enrolled in our prospective registry. Standardized perioperative data were collected including a preoperative neurological screening tool. Either interscalene or supraclavicular block was performed at the discretion of the clinical team. Standardized follow-up was performed in the postanesthesia care unit and at 1 week. Postoperative neurological symptoms (PONS) were assessed at the 1-week follow-up with the same screening tool by a blinded neurologist.

RESULTS

Ultrasound-guided interscalene (n = 515) and supraclavicular (n = 654) blocks had excellent anesthetic success (99.8%; 95% confidence interval [CI], 99.4%-99.9%) with 0% (95% CI, 0%-0.3%) incidence of vascular puncture or intravascular injection. The incidence of hoarseness in the postanesthesia care unit was significantly less with supraclavicular (22% with 95% CI, 19%-26%) than interscalene block (31% with 95% CI, 27%-35%). The incidence of dyspnea was similar (7% for supraclavicular vs 10% with interscalene). No patient had a clinically apparent pneumothorax. The incidence of PONS was very low (0.4% with 95% CI, 0.1%-1%), and there was a 0% (95% CI, 0%-0.3%) incidence of permanent nerve injury.

CONCLUSIONS

Ultrasound-guided interscalene and supraclavicular blocks are effective and safe for shoulder arthroscopy. Temporary and permanent PONS is uncommon.