Continuous spinal anesthesia/analgesia vs. single-shot spinal anesthesia with patient-controlled analgesia for elective hip arthroplasty

Neuraxial anaesthesia is associated with improved outcomes and reduced postoperative complications in patients undergoing aseptic revision total hip arthroplasty

BACKGROUND

As the incidence of primary total hip arthroplasty (THA) continues to increase, revision THA (rTHA) is becoming an increasingly common procedure. rTHA is widely regarded as a more challenging procedure, with higher complication rates and increased medical, social and economic burdens when compared to its primary counterpart. Given the complexity of rTHA and the projected increase in incidence of these procedures, patient optimisation is becoming of interest to improve outcomes. Anaesthetic choice has been extensively studied in primary THA as a modifiable risk factor for postoperative outcomes, showing favourable results for neuraxial anaesthesia compared to general anaesthesia. The impact of anaesthetic choice in rTHA has not been studied previously.

METHODS

A retrospective study was performed using the American College of Surgeons National Surgical Quality Improvement Program database. Patients who underwent rTHA between 2014 and 2017 were divided into 3 anaesthesia cohorts: general anaesthesia, neuraxial anaesthesia, and combined general-regional (neuraxial and/or peripheral nerve block) anaesthesia. Univariate and multivariate analyses were used to analyse patient characteristics and 30-day postoperative outcomes. Bonferroni correction was applied for post-hoc analysis.

RESULTS

In total, 5759 patients were identified. Of these, 3551 (61.7%) patients underwent general anaesthesia, 1513 (26.3%) patients underwent neuraxial anaesthesia, and 695 (12.1%) patients underwent combined general-regional anaesthesia. On multivariate analysis, neuraxial anaesthesia was associated with decreased odds for any-one complication (OR 0.635; p < 0.001), perioperative blood transfusion (OR 0.641; p < 0.001), and extended length of stay (OR 0.005; p = 0.005) compared to general anaesthesia.

CONCLUSIONS

Relative to those receiving general anaesthesia, patients undergoing neuraxial anaesthesia are at decreased risk for postoperative complications, perioperative blood transfusions, and extended length of stay. Prospective controlled trials should be conducted to verify these findings.

A guide to regional analgesia for Total Knee Arthroplasty

Regional analgesia has been introduced successfully into the postoperative pain management after total knee arthroplasty, reducing pain scores, opioid use and adverse effects.

Combination of regional analgesia techniques is associated with better pain management and lower side effects than single regional techniques.

Adductor canal block provides good analgesia and considerably lower detrimental effect in muscular strength than femoral nerve block, enhancing surgical recovery.

Infiltration techniques may have equivalent analgesic effect than epidural analgesia and peripheral nerve blocks, however there should be awareness of dose dependent toxicity.

Novel long-acting local anesthetics role for regional analgesia is still to be determined, and will require larger randomized trials to support its advantage over traditional local anesthetics.

Cite this article: EFORT Open Rev 2021;6:1181-1192. DOI: 10.1302/2058-5241.6.210045

Procedure-specific acute pain trajectory after elective total hip arthroplasty: systematic review and data synthesis

BACKGROUND

For most procedures, there is insufficient evidence to guide clinicians in the optimal timing of advanced analgesic methods, which should be based on the expected time course of acute postoperative pain severity and aimed at time points where basic analgesia has proven insufficient.

METHODS

We conducted a systematic search of the literature of analgesic trials for total hip arthroplasty (THA), extracting and pooling pain scores across studies, weighted for study size. Patients were grouped according to basic anaesthetic method used (general, spinal), and adjuvant analgesic interventions such as nerve blocks, local infiltration analgesia, and multimodal analgesia. Special consideration was given to high-risk populations such as chronic pain or opioid-dependent patients.

RESULTS

We identified and analysed 71 trials with 5973 patients and constructed pain trajectories from the available pain scores. In most patients undergoing THA under general anaesthesia on a basic analgesic regimen, postoperative acute pain recedes to a mild level (<4/10) by 4 h after surgery. We note substantial variability in pain intensity even in patients subjected to similar analgesic regimens. Chronic pain or opioid-dependent patients were most often actively excluded from studies, and never analysed separately.

CONCLUSIONS

We have demonstrated that it is feasible to construct procedure-specific pain curves to guide clinicians on the timing of advanced analgesic measures. Acute intense postoperative pain after THA should have resolved by 4-6 h after surgery in most patients. However, there is a substantial gap in knowledge on the management of patients with chronic pain and opioid-dependent patients.

Radical cystectomy in frail octogenarians in thoracic continuous spinal anesthesia and analgesia: a pilot study

BACKGROUND

Radical cystectomy (RC) is the gold standard therapy in nonmetastatic muscle-invasive bladder cancer and is usually performed under general anesthesia (GA). GA is high risk in most older patients due to comorbidities. Continuous spinal anesthesia (CSA) may be an alternative solution to reduce postoperative morbidity in elderly. The aim of this study was to assess the feasibility, morbidity, and mortality of RC performed under CSA in octogenarian patients.

METHODS

We retrospectively reviewed data of five frail patients aged ⩾80 who underwent RC in CSA. CSA was achieved starting with 2.5 mg hyperbaric bupivacaine plus 25 µg fentanyl. Postoperative analgesia was achieved through the intrathecal catheter, using continuous delivery of levo-bupivacaine 60 mg plus fentanyl 75 µg in 72 hours.

RESULTS

Surgery was completed in all cases in CSA. No patients required postoperative intensive care unit admission. Complications were Clavien I for four in three patients, Clavien II for seven in five patients, and Clavien IIIb for one patient. Postoperative consumption of painkillers was negligible. Oral feeding resumed within 3 days in all cases. The mean postoperative stay was 9.6 days. All patients were alive at 3 months of follow up.

CONCLUSIONS

Management of muscle-invasive bladder cancer (MIBC) in older patients is becoming an important issue due to the continuous aging of the population. Age should not preclude RC, but careful management is mandatory because perioperative morbidity and mortality are increased in the elderly. Our preliminary results show that CSA and analgesia is a feasible option as an additional way to reduce morbidity and mortality in frail octogenarians who require RC.

Continuous spinal analgesia with levobupivacaine for postoperative pain management: Comparison of 0.125% versus 0.0625% in elective total knee and hip replacement: A double-blind randomized study

Background and Aims:

Continuous spinal anesthesia (CSA) has not been widely used for postoperative analgesia, mainly to avoid complications from the subarachnoid injection. Recently, the introduction of low caliber CSA catheters (Spinocath^®), has allowed to decrease anesthetics doses and volumes with good analgesia and reduced complications. The aim of this present study was to compare two concentrations of levobupivacaine administered through CSA for postoperative pain management after major orthopedic surgery. Secondary outcomes were adverse events associated with CSA.

Material and Methods:

Thirty-two patients were randomized to receive sufentanil 1 mcg/h plus levobupivacaine 0.125%-1 ml/h (Group A_0.125) or 0.0625%-2 ml/h (Group B_0.0625) for postoperative analgesia through CSA catheter, connected to the elastomeric pump over 48 h. The quality of analgesia was assessed based on pain intensity by Visual Analogic Scale (VAS). Sensory and motor function, hemodynamic, and respiratory parameters were recorded for 96 h after surgery, after which the catheter was removed. In addition, joint mobility was assessed, and any side effects were noted.

Results:

VAS score was ≤30 mm in 25 patients. Three patients in Group A_0.125 and 4 in Group B_0.0625 (NS), received a rescue dose of levobupivacaine. Median VAS in Group A_0.125 was lower than in Group B_0.0625 on T_1h (8 ± 11 vs 16 ± 11; P < 0.05), and on T_4h (11 ± 8 vs 18 ± 1; P < 0.05). All patients remained hemodynamically stable. There were no significant differences between groups for postoperative joints mobility.

Conclusion:

Levobupivacaine at a dose of 1.25 mg/h administered by CSA provides good quality analgesia independent of concentration and solution volume in patients undergoing total knee and hip replacement.

Is there a difference in postdural puncture headache after continuous spinal anesthesia with 28G microcatheters compared with punctures with 22G Quincke or Sprotte spinal needles?

In this retrospective study, the question was raised and answered whether the rate of postdural puncture headache (PDPH) after continuous spinal anesthesia with a 28G microcatheter varies using a Quincke or a Sprotte needle. The medical records of all patients with allogenic joint replacement of the knee or hip or arthroscopic surgery of the knee joint undergoing continuous spinal anesthesia with a 22G Quincke (n=1,212) or 22G Sprotte needle (n=377) and a 28G microcatheter during the past 6 years were reviewed. We obtained the approval of the ethical committee. The rates of PDPH were statistically not different between both groups: 1.5% of patients developed PDPH after dura puncture with a Quincke needle and 2.1% with a Sprotte needle in women and men.

Continuous spinal anaesthesia versus ultrasound-guided combined psoas compartment-sciatic nerve block for hip replacement surgery in elderly high-risk patients: a prospective randomised study

Background

Our aim is to compare the hemodynamic effects of combined psoas compartment-sciatic nerve block (PCSNB) with continuous spinal anaesthesia (CSA) in elderly high-risk patients undergoing hip replacement surgery.

Methods

Seventy patients over the age of 60 with ASA III or IV physical status were randomly allocated to two groups: In the PCSNB group, ultrasound-guided psoas compartment block was performed with modified Winnie technique using 30 mL of 0.25% bupivacaine with 1:200.000 epinephrine (5 μgr/mL) and iliac crest block was performed using the same local anaesthetic solution (5 mL). All patients in the PCSNB group needed continuing infusion of propofol (2 mg/kg/h) during operation. In the CSA group, CSA was performed in the L₃-L₄ interspaced with the patient in lateral decubitus position using 2.5 mg of isobaric bupivacaine 0.5%. When sensory block was not reached to the level of T₁₂ within 10 minutes in the CSA group, additional 2.5 mg of isobaric bupivacaine 0.5% was administered through the catheter at 5-min intervals by limiting the total dose of 15 mg until a T₁₂ level of the sensory block was achieved.

Results

The PCSNB group had significantly higher mean arterial blood pressure values at the beginning of surgery and at 5^th, 10^th and 20^th minutes of surgery compared to the CSA group (P =0.038, P =0.029, P =0.012, P =0.009 respectively). There were no significant differences between groups in terms of heart rate and peripheral oxygen saturation values during surgery and the postoperative period (P >0.05). Arterial hypotension required ephedrine was observed in 13 patients in the CSA and 4 patients in the PCSNB group (P =0.012).

Conclusions

CSA and PCSNB produce satisfactory quality of anaesthesia in elderly high-risk patients with fewer hemodynamic changes in PCSNB cases compared with CSA cases.

Trial registration

Australian New Zealand Clinical Trials Registry: ACTRN12614000658617, Registered 24 June 2014.

Continuous Spinal Anaesthesia for Hip Fracture Surgery in a High-Risk Patient

Elderly patients have increased risk for perioperative mortality and morbidity due to additional comorbidities, such as cardiac diseases. Regional anaesthesia techniques are usually preferred in high-risk patients due to some advantages, such as the maintenance of cardiovascular stability and early postoperative mobilisation. This case presents the anaesthetic approach in a 55-year-old male patient with low ejection fraction that underwent hip fracture surgery. In this present case, continuous spinal anaesthesia with low-dose hyperbaric bupivacaine provided safe and effective anaesthesia during surgery with minimal haemodynamic changes and adequate analgesia during the first 24 hours after surgery.

Comparison of Continuous Femoral Nerve Block, Caudal Epidural Block, and Intravenous Patient-controlled Analgesia in Pain Control After Total Hip Arthroplasty: A Prospective Randomized Study

Thirty-six patients who underwent primary unilateral total hip arthroplasty (THA) were randomly allocated to 4 groups with different pain control protocols; continuous femoral nerve block (FNB group), single-shot caudal epidural block with morphine (EB group), intravenous patient-controlled analgesia with fentanyl (IV-PCA group), and systemic administration of nonsteroidal anti-inflammatory drugs (NSAIDs group). Postoperative pain was assessed using the numerical rating scale (NRS) scores and the analgesic effect was compared among the groups. The NRS upon arrival at the recovery room and 6 hours after surgery in the FNB, EB, and IV-PCA groups were significantly lower than that in the NSAIDs group. The amount of additional analgesics requested by the patient was smaller in the FNB, EB, and IV-PCA groups as compared to the NSAIDs group. Regarding the complications related to the analgesia, 5 of the 9 patients in the IV-PCA group complained nausea and vomiting and received antiemetic drugs. Delay in the rehabilitation process due to drowsiness was encountered in 3 patients in this group, while no patient in the FNB and EB groups suffered from delayed rehabilitation. Considering both the analgesic effect and the potential risk of complications, continuous femoral nerve blocks and caudal epidural blocks for are recommended for postoperative pain control after THA procedure.

Comparison of unilateral spinal and continous spinal anesthesia for hip surgery in elderly patients

BACKGROUND

Continous spinal anesthesia (CSA) and frequently unilateral spinal anesthesia (USpA) are usually preferred for lower extremity surgeries. In this study, we aimed to compare the effects of these anesthetic techniques, on hemodynamic parameters, quality of anesthesia and complications in elderly patients undergoing hip surgeries.

METHODS

Forty patients aged 65 years and older, assigned to receive either CSA or USpA with 7.5 mg (1.5 cc) 0.5% hyperbaric bupivacaine initially. In CSA group, additional doses of 2.5 mg bupivacaine were applied until sensory block reach to T10. Maximum sensorial block level, time to reach the level of T10 (defined as onset time) and to regress to T12, hemodynamic parameters and ephedrine requirements were recorded peroperatively and during 2 h postoperatively.

RESULTS

Hemodynamic parameters, ephedrine requirements and regression of sensory block by two levels were similar in two groups. The onset time of anesthesia was significantly longer in USpA group than CSA group. Neuraxial anesthesia had to be converted to general anesthesia in 5 patients (25%) in CSA group and 1 patient (5%) in USpA group.

CONCLUSIONS

We conclude that both USpA and CSA techniques have similar effects in elderly high risk patients. On the other hand, USpA is more preferable for surgeries with shorter durations due to its low cost and high success rate.

Continuous spinal anesthesia for lower limb surgery: a retrospective analysis of 1212 cases

Background

Continuous spinal anesthesia is a very reliable and versatile technique for providing effective anesthesia and analgesia. However, the incidence of possible complications, including postdural puncture headache or neurological impairment, remains controversial. Therefore, the aim of the present retrospective study was to analyze a large number of patients for the incidence of adverse events after continuous spinal anesthesia with a microcatheter.

Methods

This retrospective study was conducted on 1212 patients who underwent surgery of the lower extremities with continuous spinal anesthesia, which was administered with 22-gauge Quincke spinal needles and 28-gauge microcatheters. Sociodemographic and clinical data were available from the patient records, and data on headaches and patient satisfaction were drawn from a brief postoperative patient questionnaire.

Results

The patient population included 825 females (68%) and 387 males; the median age was 61 (56–76). The types of operations performed were 843 hip prostheses, 264 knee prostheses, and 105 other leg operations. No major complications were observed in any of these patients. Tension headaches were experienced by 190 (15.7%) patients, but postdural puncture headaches were reported by only 18 (1.5%) patients. Nearly all patients (98.4%) were satisfied with continuous spinal anesthesia and confirmed that they would choose this kind of anesthesia again.

Conclusion

Based on the findings of this large data analysis, continuous spinal anesthesia using a 28-gauge microcatheter appears to be a safe and appropriate anesthetic technique in lower leg surgery for aged patients.

[Continuous spinal anesthesia and pulmonary arterial hypertension]

We report the use of continuous spinal anesthesia for hip fracture surgery in a patient with pulmonary arterial hypertension. Preoperative evaluation, anesthetic technique and preoperative monitoring are discussed.

Post-dural puncture headache

Since August Bier reported the first case in 1898, post-dural puncture headache (PDPH) has been a problem for patients following dural puncture. Clinical and laboratory research over the last 30 years has shown that use of smaller-gauge needles, particularly of the pencil-point design, are associated with a lower risk of PDPH than traditional cutting point needle tips (Quincke-point needle). A careful history can rule out other causes of headache. A postural component of headache is the sine qua non of PDPH. In high-risk patients < 50 years, post-partum, in the event a large-gauge needle puncture is initiated, an epidural blood patch should be performed within 24–48 hours of dural puncture. The optimum volume of blood has been shown to be 12–20 mL for adult patients. Complications caused by autologous epidural blood patching (AEBP) are rare.

Postdural puncture headache

Postdural puncture headache (PDPH) has been a problem for patients, following dural puncture, since August Bier reported the first case in 1898. His paper discussed the pathophysiology of low-pressure headache resulting from leakage of cerebrospinal fluid (CSF) from the subarachnoid to the epidural space. Clinical and laboratory research over the last 30 years has shown that use of small-gauge needles, particularly of the pencil-point design, is associated with a lower risk of PDPH than traditional cutting point needle tips (Quincke-point needle). A careful history can rule out other causes of headache. A postural component of headache is the sine qua non of PDPH. In high-risk patients , for example, age < 50 years, postpartum, large-gauge needle puncture, epidural blood patch should be performed within 24–48 h of dural puncture. The optimum volume of blood has been shown to be 12–20 mL for adult patients. Complications of AEBP are rare.

Does regional anaesthesia improve outcome after total hip arthroplasty? A systematic review

Total hip arthroplasty (THA) is amenable to a variety of regional anaesthesia (RA) techniques that may improve patient outcome. We sought to answer whether RA decreased mortality, cardiovascular morbidity, deep venous thrombosis (DVT) and pulmonary embolism (PE), blood loss, duration of surgery, pain, opioid-related adverse effects, cognitive defects, and length of stay. We also questioned whether RA improved rehabilitation. To do so, we performed a systematic review of the contemporary literature to compare general anaesthesia (GA) and RA and also systemic and regional analgesia for THA. To reflect contemporary surgical and anaesthetic practice, only randomized controlled trials (RCTs) from 1990 onward were included. We identified 18 studies involving 1239 patients. Only two of the 18 trials were of Level I quality. There is insufficient evidence from RCTs alone to conclude if anaesthetic technique influenced mortality, cardiovascular morbidity, or the incidence of DVT and PE when using thromboprophylaxis. Blood loss may be reduced in patients receiving RA rather than GA for THA. Our review suggests that there is no difference in duration of surgery in patients who receive GA or RA. Compared with systemic analgesia, regional analgesia can reduce postoperative pain, morphine consumption, and nausea and vomiting. Length of stay is not reduced and rehabilitation does not appear to be facilitated by RA or analgesia for THA.

Feasibility of infusion pumps for continuous spinal administration of local anesthetics in post-operative pain therapy

BACKGROUND AND OBJECTIVES

For completion of perioperative care and for general ethical considerations, any intraoperatively used catheter technique should be utilizable for post-operative pain therapy. Continuous spinal anesthesia (CSA) is an established form of local anesthetic application. However, for its use in post-operative therapy, infusion pumps are required that are technically able to deliver low rates and are distinctive in design to avoid possible pump or medication swaps. Because of a lack of devices specifically designed for CSA, we investigated the potential deployability of infusion pumps for post-operative pain therapy via CSA microcatheters, which were originally designed and approved for different applications.

METHODS

The accuracy of infusion rates of three different pumps was measured in a liquor model environment. Furthermore, we investigated safety and user-friendliness by interviewing 30 anesthesiologists and 15 pain nurses.

RESULTS

Except for the first hour of infusion, all pumps provided comparable and adequate flow profiles. However, interviews revealed significant risk factors for all pumps in terms of swapping devices, lines or medications and misprogramming the units.

DISCUSSION

All pumps tested were technically able to deliver accurate flow rates; however, because the non-CSA-specific design involves the risk of medication overdosage and syringe swaps, none of the systems tested can be recommended for routine use in post-operative CSA, irrespective of the fact that it was an off-label application anyway. Therefore, to ensure patient safety, continuous spinal administration of local anesthetics via microcatheters is a questionable method of post-operative pain therapy as long as non-specific pumps are used.

[Pain therapy for the lower extremities]

Pain therapy after surgical procedures of the lower extremity is an important goal, whereas insufficient analgesia leads to an essential reduction of the patient's mobility and convalescence. If possible, regional anaesthetic and intrathecal procedures for pre-, intra- and postoperative analgesia should be used. Systemic analgesics should not be used preoperatively, whereas non-opioids and opioids are recommended postoperatively. Surgical options that adequately reduce pain are intra-articular injection of local anaesthetics alone or in combination with opioids and cooling and physiotherapeutic treatment regimens after joint procedures. There is no scientific rationale as an argument for inserting drains. The surgical approach depends more on the individual patient's anatomical characteristics. Whereas the regional analgesic regimen is more effective than systemic therapy, sufficient tools for pain reduction during surgical procedures of the lower extremity are at the orthopaedic surgeon's disposal, too.

Spinal anaesthesia with a micro-catheter in high-risk patients undergoing colorectal cancer and other major abdominal surgery

Extended spinal anaesthesia using a spinal micro-catheter was used as a primary method of anaesthesia for elective colorectal cancer surgery in 68 high risk patients over a 14-year period in our institution. The technique was also useful in eight elective and 13 emergency abdominal surgeries. All patients suffered from severe chronic obstructive airway disease requiring multiple inhalers and drugs (ASA III). Thirty nine of these patients also suffered from angina, myocardial infarction, diabetes and other systemic diseases (ASA IV). Surgery included right hemicolectomy, left hemicolectomy, total colectomy, sigmoid colectomy, Hartman's resection, anterior resection of rectum, abdominoperineal resection, cholecystectomy (open and laparoscopic) and obstructed inguinal hernia requiring laparotomy. Spinal anaesthesia was performed under strict aseptic conditions with a 22 gauge spinal needle with a mixture consisting of 2.75ml of 0.5% heavy bupivacaine and 0.25ml of fentanyl (25microg). This was followed by placement of a spinal micro-catheter and the duration of anaesthesia was extended by intermittent injection of 0.5% isobaric bupivacaine. Brief hypotension occurred in 12.4% of patients during the establishment of anaesthetic block height to T6-7 and was duly treated with intravenous administration of fluid and ephedrine hydrochloride. Good anaesthesia resulted in all patients except for brief discomfort in some patients during hemicolectomy surgery possibly due to the dissection and traction on the peritoneum causing irritation to the diaphragm. The use of sedation was avoided. General anaesthesia was administered in one patient and this patient required postoperative ventilation and cardiovascular support in the Intensive Care Unit. The spinal micro-catheter was removed at the end of surgery. Postoperative pain relief was obtained by administering intravenous morphine through a patient controlled analgesia machine in the critical care ward area (High Dependency Unit). There was a low incidence of minor postoperative side effects such as nausea (14.6%), vomiting (7.9%), minor post dural puncture headache (5.6%) and pruritus (5.6%). We conclude that spinal anaesthesia with a micro-catheter may be used as a primary method of anaesthesia for colorectal cancer surgery and other major abdominal surgery in high-risk patients for whom general anaesthesia would be associated with higher morbidity and mortality.

Isobaric bupivacaine via spinal catheter for hip replacement surgery: ED50 and ED95 dose determination

BACKGROUND

Continuous spinal anaesthesia with spinal catheters allows incremental dosing of the local anaesthetic and, consequently, less haemodynamic change. However, little is known about the required doses. Therefore, we designed a study to assess the local anaesthetic doses of isobaric bupivacaine which were effective in 50% (ED50) and 95% (ED95) of patients undergoing hip replacement surgery.

METHODS

Forty-eight patients undergoing hip replacement surgery were randomly allocated to one of six possible groups of eight patients to receive 6, 7, 8, 9, 10 or 12 mg of isobaric bupivacaine in a double-blind manner. The ED50 and ED95 values were calculated by a logistic regression model. The position of the spinal catheter tip was confirmed by X-rays.

RESULTS

The ED50 and ED95 values were 7.1 mg (95% confidence interval, 6.0-8.4) and 12.3 mg (95% confidence interval, 8.9-15.7), respectively. The location of the tip of the intrathecal catheter had no effect on local anaesthetic requirements. Eight patients required ephedrine after anaesthesia induction and a further 11 patients required ephedrine for correction of hypotension during surgery.

CONCLUSION

The observed ED50 and ED95 values may guide us to use small doses of isobaric bupivacaine for hip replacement surgery. Hypotension is still possible even if low doses of isobaric bupivacaine are used.

A procedure-specific systematic review and consensus recommendations for analgesia after total hip replacement

Total hip replacement is a major surgical procedure usually associated with significant pain in the early postoperative period. Several anaesthetic and analgesic techniques are in common clinical use for this procedure but, to date, clinical studies of pain after total hip replacement have not been systematically assessed. Using the Cochrane protocol, we have conducted a systematic review of analgesic, anaesthetic and surgical interventions affecting postoperative pain after total hip replacement. In addition to the review, transferable evidence from other relevant procedures and clinical practice observations collated by the Delphi method were used to develop evidence-based recommendations for the treatment of postoperative pain. For primary total hip replacement, PROSPECT recommends either general anaesthesia combined with a peripheral nerve block that is continued after surgery or an intrathecal (spinal) injection of local anaesthetic and opioid. The primary analgesic technique should be combined with a step-down approach using paracetamol plus conventional non-steroidal anti-inflammatory drugs, with strong or weak opioids as required.

Regional anesthesia in hip surgery

Historically, general anesthesia has been the "gold standard" for surgeons and patients when major hip surgery is being done. The recent introductions of improved techniques and catheters for continuous peripheral nerve blocks have made regional anesthesia more attractive to patients and surgeons. We focus on current trends and future directions in perioperative pain management for major orthopaedic procedures done on the hip. The use of epidural or spinal anesthesia during major hip surgery has been linked to a reduced risk of perioperative complications like deep venous thrombosis, less deterioration of cerebral and pulmonary functions in patients who are at high risk for complications, and overall reduced blood loss. In addition, continuous peripheral nerve blocks showed effective and safe postoperative pain control, allowing for lower opioids consumption, improved and earlier rehabilitation, and high patient satisfaction. Accurate patient selection and patient education are fundamental for the success of any regional anesthesia technique. Modern regional anesthesia for major hip surgery includes the use of a single shot and continuous epidural injections, single-shot and continuous spinal injection, continuous lumbar plexus blockade, and continuous peripheral blockade of the femoral and sciatic nerves. Continuous peripheral nerve blocks represent an adjunctive, effective, and safe technique for postoperative pain control after total hip arthroplasty. Future directions in postoperative pain control include the creation of a comprehensive system that supervises the use of continuous peripheral nerve blocks outside the acute inpatient setting for few days following the surgical procedure.

LEVEL OF EVIDENCE

Therapeutic study, Level V (expert opinion). See the Guidelines for Authors for a complete description of levels of evidence.

The Mechanical Properties of Continuous Spinal Small-Bore Catheters

Continuous spinal anesthesia (CSA) has a nearly 100-yr history. In situations of difficult removal of a CSA small-bore catheter, mechanical properties of the different catheters might be important, because breakage could occur. We compared 5 different CSA small-bore catheters, 22- to 28-gauge from 3 manufacturers, for tensile strength, tensile stress, distension, and yield strength. Maximal tensile strength is the force applied before breakage of the catheter. The material characteristics of different CSA small-bore catheters for maximal tensile strength were: 22-gauge = 29.56 +/- 1.56 (mean +/- sd) Newton (N), 24-gauge = 16.77 +/- 1.61 N, 25-gauge = 9.20 +/- 0.48 N, 27-gauge = 4.61 +/- 0.25 N, 28-gauge = 5.07 +/- 0.59 N at room temperature. A strong correlation between maximal tensile strength and the outer diameter (r = 0.957, P < 0.001) and maximal tensile strength and the wall thickness (r = 0.9, P < 0.001) was observed. Although extrapolation from experimental studies to clinical routine should be made with care, our data suggest that catheters with higher-strength characteristics may reduce the risk of catheter breakage in patients, although clinical correlations are lacking.