Clinical Evaluation of a Modified Posterior Anatomical Approach to Performing the Popliteal Block:

Assessment of cardiotoxicity and plasma ropivacaine concentrations after serratus intercostal fascial plane block in an experimental model

Serratus intercostal fascial plane block (SIFPB) has emerged as an alternative to paravertebral block in breast surgery. It involves the administration of high volumes and doses of local anesthetics (LA) that can potentially reach toxic levels. Ropivacaine is widely used in thoraco-fascial blocks; however, there is no information on the plasma concentrations attained after SIPFB and whether they are associated with cardiotoxicity. Plasma concentrations of ropivacaine and its electrophysiological effects were evaluated in eight pigs after bilateral SIFPB with ropivacaine in doses of 3 mg/kg. Plasma concentrations, electrophysiological and hemodynamic parameters were measured sequentially for the following 180 min until the end of the study. The area under the curve, the maximum plasma concentration (C_max) and the time to reach C_max (t_max) were calculated. The median arterial ropivacaine concentration C_max was, 2.34 [1.40 to 3.74] µg/ml. The time to reach the highest concentration was 15 [10 to 20] min. Twenty-five percent of the animals had arterial concentrations above the lower limit concentration of ropivacaine for LA systemic toxicity (3.4 µg/ml). No alterations were observed in the electrophysiological or electrocardiographic parameters except for a prolongation of the QTc interval, from 489 ± 30 to 544 ± 44 ms (Δ11.38 ± 6%), P = 0.01. Hemodynamic parameters remained in the physiological range throughout the study. SIFPB with ropivacaine in doses of 3 mg/kg has reached potentially toxic levels, however, it has not been associated with adverse electrophysiological or hemodynamic effects.

Techniques and complications of popliteal nerve blocks

BACKGROUND

Use of popliteal nerve blocks (PNBs) as an alternative or adjunctive therapy to traditional methods of pain control (e.g., systemic or spinal anesthesia and opioids) is increasingly popular in foot and ankle surgery.

METHODS

We reviewed online databases for literature on PNBs in foot and ankle surgery to analyze the various techniques and positioning used, the influence of drugs on their efficacy, and possible complications associated with their use. Thirty articles were identified with a predefined search criteria, followed by a review process for relevance.

RESULTS

Patient demographics, procedure specifics, and block techniques, such as anesthetic used, can impact the duration and success of a PNB. Administration with ultrasound guidance proved superior to nerve stimulation, and preoperative administration was superior to postoperative administration.

CONCLUSIONS

PNBs are an effective method to control postoperative pain with minimal complications, leading to decreased analgesic use, earlier discharge, and higher patient satisfaction.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

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.

Intraoperative management of critical arrhythmia

The incidence of intraoperative arrhythmia is extremely high, and some arrhythmias require clinical attention. Therefore, it is essential for the anesthesiologist to evaluate risk factors for arrhythmia and understand their etiology, electrophysiology, diagnosis, and treatment. Anesthetic agents reportedly affect normal cardiac electrical activity. In the normal cardiac cycle, the sinoatrial node initiates cardiac electrical activity through intrinsic autonomous pacemaker activity. Sequential atrial and ventricular contractions result in an effective cardiac pumping mechanism. Arrhythmia occurs due to various causes, and the cardiac pumping mechanism may be affected. A severe case may result in hemodynamic instability. In this situation, the anesthesiologist should eliminate the possible causes of arrhythmia and manage the condition, creating hemodynamic stability under proper electrocardiographic monitoring.

[Perioperative treatment of patients with long QT syndrome]

Long QT syndrome (LQTS) is caused by a change in cardiac repolarization due to functional ion channel dysfunction which is associated with an elongation of the QT interval (hence the name) in the electrocardiogram and a predisposition to cardiac rhythm disorders (e.g. torsade de pointes, TdP) as well as cardiac events up to sudden cardiac death. There is a congenital (cLQTS) and an acquired (aLQTS) form of the disease. The prevalence of cLQTS is 1 in 2000 but aLQTS is much more common and includes a grey area due to many asymptomatic patients. The LQTS is, therefore, more common than malignant hyperthermia which is much discussed in anesthesiology and has a reported prevalence in the population of 1:3000. Considering the prevalence of both aLQTS as well as cLQTS the importance of the LQTS seems to be underestimated in current perioperative care. Potential perioperative risks of such patients can be significantly reduced by appropriate patient management. This includes adequate preoperative preparation, the correct choice of anesthetic medication as well as adequate perioperative monitoring and preparedness for immediate pharmaceutical and electrical intervention in case of typical cardiac rhythm disturbances, such as TdP arrhythmia.

Starting with ultrasonography decreases popliteal block performance time in inexperienced hands: a prospective randomized study

Background

The widespread of hallux valgus surgery in a day care setting enhanced the role of regional anaesthesia in the last few years. Sciatic nerve block at popliteal fossa has been shown to provide safe and effective analgesia. Our purpose was to compare the success rate and performance time of popliteal block during resident’s training for regional anaesthesia by using nerve stimulation (NS) or combined nerve stimulation and ultrasound (NS + US).

Methods

70 adult patients undergoing hallux valgus surgery were randomly assigned to receive sciatic nerve block at popliteal fossa with US+NS or NS alone with a double injection technique for peroneal and tibial branches, respectively. Two residents experienced with nerve stimulator performed the procedures after a learning phase concerning ultrasonography. A local anaesthetic solution, containing 10 mL of 0.75% ropivacaine and 10 mL of 2% lidocaine was used: 12 mL were infiltrated close the tibial nerve, and 8mL were infiltrated close the common peroneal nerve. Block success rate, sensory block onset time, block performance time were evaluated. Recourse to general anaesthesia was considered as failure.

Results

No differences were detected in success rate and onset time of sensory block between the two groups (P > 0.05). The time to block tibial nerve and the overall block time were significantly faster in US+NS group (P < 0.05).

Conclusions

Ultrasound guidance for popliteal nerve block resulted in similar success rate with a faster procedure time when compared with nerve stimulator, thus providing a possible effect on resident education and operating room efficiency.

Buprenorphine added to levobupivacaine enhances postoperative analgesia of middle interscalene brachial plexus block

PURPOSE

The aim of this study was to assess whether addition of epineural buprenorphine prolonged postoperative analgesia of middle interscalene brachial plexus block (MIB) with levobupivacaine.

METHODS

One hundred and fifty consenting adult patients, scheduled for shoulder arthroscopic surgery for a rotator cuff tear under MIB with 29.5 ml of 0.75 % levobupivacaine, were randomized to receive additionally either saline or intramuscular buprenorphine 0.15 mg or epineural buprenorphine 0.15 mg. Onset of sensory and motor blocks, duration of postoperative analgesia, and consumption of postoperative analgesics were compared among the groups.

RESULTS

There were significant (P < 0.05) differences in the onset and the duration of the sensory block and in the duration of postoperative analgesia. Duration of both sensory block and postoperative analgesia was longer (P < 0.05) in patients who had received epineural buprenorphine (856.1 ± 215.2 and 1,049.7 ± 242.2 min) than in patients who had received intramuscular buprenorphine (693.6 ± 143.4 and 820.3 ± 335.3 min) or saline (488.3 ± 137.6 and 637.5 ± 72.1 min). Requirement of postoperative rescue analgesics was lower in the epineural buprenorphine group than in the other two groups. Few complications occurred from MIB (<1 %) and none from buprenorphine.

CONCLUSIONS

Epineural buprenorphine prolonged postoperative analgesia of MIB more effectively than intramuscular buprenorphine, which suggests that buprenorphine acts at a peripheral nervous system site of action.

Neuropathic complications after 157 procedures of continuous popliteal nerve block for hallux valgus surgery. A retrospective study

BACKGROUND

Continuous peripheral nerve block (CPNB), in particular at the popliteal fossa, is widely used in orthopedic surgery, allowing good postoperative analgesia. Possible neuropathic complications, however, remain poorly known.

OBJECTIVE

To review the characteristics of peripheral neuropathy (PN) after sciatic CPNB at the popliteal fossa, estimating prevalence, severity, evolution and possible risk factors, especially those relating to the procedure.

METHODS

Retrospective study of PN associated with popliteal fossa CPNB for hallux valgus surgery, between November 1st, 2005 and November 1st, 2009. All procedures were analyzed (type of anesthesia, approach, nerve location technique, number of procedures by operator) with, for each case of PN, analysis of clinical and electromyographic data.

RESULTS

One hundred and fifty seven sciatic CPNBs were performed (92% women; mean age, 55 years). The approach was lateral (n=62), posterior (n=74) or unknown (n=21). Ultrasound guidance was combined to neurostimulation for 69 patients (44%). Three women (prevalence=1.91%), aged 19, 24 and 65 years respectively, developed associated common superficial peroneal and sural nerve injury (2), axonal on electromyography, with motor (n=1) and/or sensory (n=3) residual dysfunction.

DISCUSSION

The higher prevalence found in the present study than in the literature (0 to 0.5%) raises questions of methodological bias or technical problems. The common peroneal and sural nerves seem to be exposed, unlike the tibial. Several mechanisms can be suggested: anesthetic neurotoxicity, direct mechanical lesion, or tourniquet-related ischemia and conduction block. Further studies are necessary to determine the ideal anesthetic procedure.

CONCLUSION

Patients should be informed of the potential risk, however rare, even during mild surgery. The best possible technique should be implemented, with reinforced surveillance.

Continuous peripheral nerve blocks in the hospital and at home

A single-injection peripheral nerve block using long-acting local anesthetic provides analgesia for 12 to 24 hours; however, many surgical procedures result in pain that lasts far longer. One relatively new option is a continuous peripheral nerve block (CPNB): local anesthetic is perfused via a perineural catheter directly adjacent to the peripheral nerve(s) supplying the surgical site, providing potent, site-specific analgesia. CPNB results in decreased pain, opioid requirements, opioid-related side effects, and sleep disturbances; in some cases, accelerating resumption of tolerated passive joint range-of-motion and increasing patient satisfaction. Ambulatory perineural infusion may be provided using a portable infusion pump, in some cases resulting in decreased hospitalization duration and related costs. Serious complications are rare, but may result in significant morbidity.

Ultrasound guidance for pediatric peripheral nerve blockade

There is an increasing trend in the use of peripheral nerve blockade for postoperative analgesia in children, and the use of ultrasound guidance to perform peripheral nerve blocks is gaining popularity. A thorough knowledge of anatomy will help in performing the appropriate block, and will also aid in better use and understanding of ultrasound guidance. In this article, we briefly review the use of ultrasound guidance to perform common upper and lower extremity and truncal blocks.

A report of UK experience in 917 cases of day care foot surgery using a validated outcome tool

BACKGROUND

Day case surgery is an increasingly important treatment modality and one that foot surgery is particularly well suited to.

OBJECTIVES

This article presents an in depth evaluation of the outcomes of day case foot surgery undertaken in the primary care setting.

METHOD

917 consecutive day surgery cases were evaluated with the Foot Health Status Questionnaire (FHSQ), patient satisfaction questionnaires and complication audits.

RESULTS

917 separate day care admissions were audited (696 females and 221 males). The average age at time of surgery was 50 years (range 14-100, S.D. 11). Post-operative follow up was usually complete by 26 weeks (range 21-218 weeks, S.D. 145). A total of 2772 individual procedures with patients receiving between one and five procedures per admission. The majority of patients (81%, N=743) opted for local anaesthesia. The FHSQ scores for foot pain, foot function, foot health, shoe fitting, general health, physical activity, social capacity and vigour improved. Patient satisfaction results were favourable and complication rates were within acceptable limits.

CONCLUSIONS

Podiatric surgery is well placed to meet both the demands of government and patients in delivering a high quality, safe and efficient treatment for patients requesting elective surgical intervention for foot deformity.

Ultrasound-guided regional anesthesia and analgesia: a qualitative systematic review

Ultrasound guidance has become popular for performance of regional anesthesia and analgesia. This systematic review summarizes existing evidence for superior risk to benefit profiles for ultrasound versus other techniques. Medline was systematically searched for randomized controlled trials (RCTs) comparing ultrasound to another technique, and for large (n > 100) prospective case series describing experience with ultrasound-guided blocks. Fourteen RCTs and 2 case series were identified for peripheral nerve blocks. No RCTs or case series were identified for perineural catheters. Six RCTs and 1 case series were identified for epidural anesthesia. Overall, the RCTs and case series reported that use of ultrasound significantly reduced time or number of attempts to perform blocks and in some cases significantly improved the quality of sensory block. The included studies reported high incidence of efficacy of blocks with ultrasound (95%-100%) that was not significantly different than most other techniques. No serious complications were reported in included studies. Current evidence does not suggest that use of ultrasound improves success of regional anesthesia versus most other techniques. However, ultrasound was not inferior for efficacy, did not increase risk, and offers other potential patient-oriented benefits. All RCTs are rather small, thus completion of large RCTs and case series are encouraged to confirm findings.

[Long QT syndrome and anaesthesia]

The long QT syndrome (LQTS) is a rare, congenital or acquired disease, which may lead to fatal cardiac arrhythmias (torsade de pointes, TdP). In all LQTS subtypes, TdPs are caused by disturbances in cardiac ion channels. Diagnosis is made using clinical, anamnestic and electrocardiographic data. Triggers of TdPs are numerous and should be avoided perioperatively. Sufficient sedation and preoperative correction of electrolyte imbalances are essential. Volatile anaesthetics and antagonists of muscle relaxants should be avoided and high doses of local anaesthetics are not recommended to date. Propofol is safe for anaesthesia induction and maintenance. The acute therapy of TdPs with cardiovascular depression should be performed in accordance with the guidelines for advanced cardiac life support and includes cardioversion/defibrillation and magnesium. Torsades de pointes may be associated with bradycardia or tachycardia resulting in specific therapeutic and prophylactic measures.

[Electrical nerve stimulation for plexus and nerve blocks]

Despite the increasing use of ultrasound, electrical nerve stimulation is commonly used as the standard for both plexus and peripheral nerve blocks. Several recent randomized trials have contributed to a better understanding of physiological and clinical correlations. Traditionally used currents and impulse widths are better defined in relation to the distance between needle tip and nerves. Commercially available devices enable transcutaneous nerve stimulation and provide new opportunities for the detection of puncture sites and for training. The electrically ideal position of the needle usually is defined by motor responses which can not be interpreted without profound anatomical knowledge. For instance, interscalene blocks can be successful even after motor responses of deltoid or pectoral muscles. Infraclavicular blocks should be aimed at stimulation of the posterior fascicle (extension). In contrast to multiple single nerve blocks, axillary single-shot blocks more commonly result in incomplete anaesthesia. Blockade of the femoral nerve can be performed without any nerve stimulation if the fascia iliaca block is used. Independently of the various approaches to the sciatic nerve, inversion and plantar flexion are the best options for single-shot blocks. Further clinical trials are needed to define the advantages of stimulating catheters in continuous nerve blocks.

Neurological complications after regional anesthesia: contemporary estimates of risk

BACKGROUND

Regional anesthesia (RA) provides excellent anesthesia and analgesia for many surgical procedures. Anesthesiologists and patients must understand the risks in addition to the benefits of RA to make an informed choice of anesthetic technique. Many studies that have investigated neurological complications after RA are dated, and do not reflect the increasing indications and applications of RA nor the advances in training and techniques. In this brief narrative review we collate the contemporary investigations of neurological complications after the most common RA techniques.

METHODS

We reviewed all 32 studies published between January 1, 1995 and December 31, 2005 where the primary intent was to investigate neurological complications of RA.

RESULTS

The sample size of the studies that investigated neurological complications after central and peripheral (PNB) nerve blockade ranged from 4185 to 1,260,000 and 20 to 10,309 blocks, respectively. The rate of neuropathy after spinal and epidural anesthesia was 3.78:10,000 (95% CI: 1.06-13.50:10,000) and 2.19:10,000 (95% CI: 0.88-5.44:10,000), respectively. For common PNB techniques, the rate of neuropathy after interscalene brachial plexus block, axillary brachial plexus block, and femoral nerve block was 2.84:100 (95% CI 1.33-5.98:100), 1.48:100 (95% CI: 0.52-4.11:100), and 0.34:100 (95% CI: 0.04-2.81:100), respectively. The rate of permanent neurological injury after spinal and epidural anesthesia ranged from 0-4.2:10,000 and 0-7.6:10,000, respectively. Only one case of permanent neuropathy was reported among 16 studies of neurological complications after PNB.

CONCLUSIONS

Our review suggests that the rate of neurological complications after central nerve blockade is <4:10,000, or 0.04%. The rate of neuropathy after PNB is <3:100, or 3%. However, permanent neurological injury after RA is rare in contemporary anesthetic practice.

Modified Coughlin procedure for surgical treatment of symptomatic tailor's bunion: a prospective followup study of 33 consecutive operations

BACKGROUND

Symptomatic tailor's bunion is a painful osseous and soft-tissue prominence at the lateral aspect of the fifth metatarsal head. If conservative treatment fails, surgery is necessary to correct the deformity and to relieve the symptoms. The "Coughlin" procedure is an established corrective diaphyseal realignment osteotomy. The purpose of this study was to analyze the results of a modification of the Coughlin procedure in a series of 24 consecutive patients.

METHODS

Between October, 1999, and August, 2002, we performed a modified Coughlin procedure for painful tailor bunions in 24 patients (33 feet). An additional bunionectomy was done only if the fifth metatarsal head remained prominent after the osteotomy (20 feet). The average age of the patients was 45 years. All patients were evaluated preoperatively and postoperatively using the AOFAS forefoot score, and the correction of the fourth-fifth intermetatarsal angle was assessed on full weightbearing dorsoplantar radiographs. The average followup was 24 months for objective and 39 months for the subjective results.

RESULTS

There were no intraoperative and postoperative complications. The mean AOFAS score increased from 55 points preoperatively to 95 points at followup. At longest followup the subjective results were rated as good or excellent in 22 patients (97%). No difference in subjective patient satisfaction was seen whether bunionectomy was done or not. The mean fourth-fifth intermetatarsal angle improved from 10.4 degrees preoperatively to 1 degree at followup. Six patients (18%) required screw removal which was carried out on an outpatient basis under local anesthesia.

CONCLUSION

The modified Coughlin procedure is a technically safe and reliable procedure for treatment of painful tailor's bunion. In our experience, it yields good or excellent results with high patient satisfaction and a low complication rate. Internal screw fixation leads to stable bony fusion with full weightbearing immediately postoperatively and is associated with a relatively low rate of implant removal.

Does the Site of Injection Distal to the Greater Trochanter Make a Difference in Lateral Sciatic Nerve Blockade?

The two components of the sciatic nerve become more distant from one another in their course down the lower limb. This may have clinical implications if a small volume of local anesthetic is used with a single injection technique. In this prospective, randomized, double-blind study, we compared two different injection sites, 20 cm and 30 cm distal to the greater trochanter, in terms of onset time and success rate of sciatic nerve blockade after a single injection of 20 mL of 1.5% mepivacaine. Fifty patients undergoing foot surgery were randomly allocated to receive a lateral sciatic nerve blockade using one of 2 levels: 20 cm distal to the greater trochanter (group proximal; n = 25) and 30 cm distal to the greater trochanter (group distal; n = 25). Twenty milliliters of 1.5% mepivacaine was injected after a flexion plantar response was obtained at <0.5 mA. Time required for onset of sensory and motor blockade of the foot was recorded. Success rate was defined as complete sensory and motor blockade in all sciatic nerve distributions associated with a pain-free surgery. Onset of complete sensory and motor blockade was faster in group proximal (12 +/- 7 min and 15 +/- 8 min, respectively) compared with group distal (19 +/- 9 min and 23 +/- 9 min; P < 0.05). Group proximal also had a more frequent success rate compared with group distal (88% versus 56%, respectively; P < 0.05). It is concluded that in lateral sciatic nerve blockade, a more proximal approach to the sciatic nerve predicts a shorter onset time and more frequent success than a more distal injection site when a single injection and a small volume of local anesthetic is used.

IMPLICATIONS

In lateral sciatic nerve blockade, a more proximal approach to the sciatic nerve provides shorter onset times and more frequent success than a more distal injection site when a single injection of 20 mL of mepivacaine 1.5% is used.

Continuous Peripheral Nerve Blocks at Home: A Review

Postoperative analgesia is generally limited to 12-16 h or less after single-injection regional nerve blocks. Postoperative analgesia may be provided with a local anesthetic infusion via a perineural catheter after initial regional block resolution. This technique may now be used in the outpatient setting with the relatively recent introduction of reliable, portable infusion pumps. In this review article, we summarize the available published data related to this new analgesic technique and highlight important issues related specifically to perineural infusion provided in patients' own homes. Topics include infusion benefits and risks, indications and patient selection criteria, catheter, infusion pump, dosing regimen, and infusate selection, and issues related specifically to home-care.

Nerve injury and regional anaesthesia

PURPOSE OF REVIEW

In recent years there has been a renewed interest in regional anaesthesia, particularly peripheral nerve blockade, not only to improve the patient's well being, but also to meet the requirements of modern orthopaedic surgery. Nerve injury in this context is the complication most feared by the patient, the anaesthesiologist and the surgeon.

RECENT FINDINGS

To date, data dealing with the incidence of nerve injury in regional anaesthesia have almost exclusively been retrieved from close claims analysis. Recently, prospective, well controlled studies have shown that severe neurologic complications rarely occur: for the upper extremity, an incidence of 0.2-1% has been reported. New insights into the mechanisms of local anaesthetic neurotoxicity have demonstrated that ropivacaine has the least potential for neurotoxicity. Administration of the lowest possible concentrated solution of local anaesthetic is likely to be even less neurotoxic. The role of local anaesthetics in the development of apoptosis is nowadays well recognized. The consequences of other factors, such as nerve stretching and compression, in the pathology of nerve damage are emphasized.

SUMMARY

Significant advances have been made in regional anaesthesia in the past 10 years. The introduction of catheter techniques has cleared the way for better regional anaesthetic and analgesic blocks. Studies dealing with placement of perineural catheters show that the catheter does not increase neurological complications. Properly performed, regional anaesthesia is a safe form of anaesthesia and the benefits far outweigh the risks.