Persistent and Chronic Perioperative Pain After Cancer Surgery.

PURPOSE OF REVIEW: Persistent and chronic pain after cancer surgery is a complex clinical problem. The etiology of pain in these cases is often multifactorial and, in addition to the surgery itself, can include or overlap with other painful syndromes such as direct effects of tumors, neuropathic pain, and pain syndromes secondary to chemotherapy and/or radiation. RECENT FINDINGS: There is a growing body of literature which suggests that treating pain in the acute and subacute periods can prevent chronic pain, an important step in reducing the morbidity of this clinical problem. This review describes the incidence of persistent pain after cancer surgery, its pathophysiology, and treatment considerations. Additional research on diagnostic criteria, pathophysiology, and novel medications, restorative therapies, and interventional treatments will be essential to continue to reduce the clinical burden of persistent and chronic perioperative pain after cancer surgery.

The External Oblique Intercostal Block: Anatomic Evaluation and Case Series.

STUDY OBJECTIVE: We report a modified block technique aimed at obtaining upper midline and lateral abdominal wall analgesia: the external oblique intercostal (EOI) block. DESIGN: A cadaveric study and retrospective cohort study assessing the potential analgesic effect of the EOI block. SETTING: Cadaver lab and operating room. PATIENTS: Two unembalmed cadavers and 22 patients. INTERVENTIONS: Bilateral ultrasound-guided EOI blocks on cadavers with 29 mL of bupivacaine 0.25% with 1 mL of India ink; single-injection or continuous EOI blocks in patients. MEASUREMENTS: Dye spread in cadavers and loss of cutaneous sensation in patients. MAIN RESULTS: In the cadaveric specimens, we identified consistent staining of both lateral and anterior branches of intercostal nerves from T7 to T10. We also found consistent dermatomal sensory blockade of T6-T10 at the anterior axillary line and T6-T9 at the midline in patients receiving the EOI block. CONCLUSIONS: We demonstrate the potential mechanism of this technique with a cadaveric study that shows consistent staining of both lateral and anterior branches of intercostal nerves T7-T10. Patients who received this block exhibited consistent dermatomal sensory blockade of T6-T10 at the anterior axillary line and T6-T9 at the midline. This block can be used in multiple clinical settings for upper abdominal wall analgesia.

Subcostal Anterior Quadratus Lumborum Block Versus Epidural Block for Analgesia in Open Nephrectomy: A Randomized Clinical Trial.

BACKGROUND: Epidural block are often used for analgesia after open nephrectomy surgery. Subcostal anterior quadratus lumborum block may be an alternative. We therefore tested the hypothesis that the continuous subcostal anterior quadratus lumborum block is noninferior to epidural block for analgesia in patients having open partial nephrectomies. METHODS: Adults having open partial nephrectomies were randomly allocated to epidural or unilateral subcostal anterior quadratus lumborum block. The joint primary outcomes were opioid consumption measured in morphine equivalents and pain measured on a numeric rating scale (0-10) from postanesthesia care unit (PACU) until 72 hours after surgery. The noninferiority deltas were 30% for opioid consumption and 1 point on a 0-10 scale for pain. Secondary outcomes included patient global assessment of pain management on the third postoperative day, the number of antiemetic medication doses through the third postoperative day, duration of PACU stay, and postoperative duration of hospitalization. RESULTS: Twenty-six patients were randomized to anterior quadratus lumborum block and 29 to epidural analgesia. Neither pain scores nor opioid consumption in the quadratus lumborum patients were noninferior to epidural analgesia. At 72 hours, mean ± standard deviation pain scores in subcoastal anterior quadratus lumborum block and epidural group were 4.7 ± 1.8 and 4.1 ± 1.7, with an estimated difference in pain scores of 0.62 (95% confidence interval [CI], 0.74-1.99; noninferiority P = .21). The median [Q1, Q3] opioid consumption was more than doubled in quadratus lumborum patients at 70 mg [43, 125] versus 30 mg [18, 75] in the epidural group with an estimated ratio of geometric means of 1.69 (95% CI, 0.66-4.33; noninferiority P = .80). Patient global assessment and duration of PACU and hospital stays did not differ significantly in the 2 groups. CONCLUSIONS: We were unable to show that subcostal anterior quadratus lumborum block are noninferior to epidural analgesia in terms of pain scores and opioid consumption for open partial nephrectomies. Effectiveness of novel blocks should be rigorously tested in specific surgical setting before widespread adoption.

Effect of Sevoflurane Versus Isoflurane on Emergence Time and Postanesthesia Care Unit Length of Stay: An Alternating Intervention Trial.

BACKGROUND: We previously reported that the duration of hospitalization was not different between isoflurane and sevoflurane. But more plausible consequences of using soluble volatile anesthetics are delayed emergence from anesthesia and prolonged stays in the postanesthesia care unit (PACU). We therefore compared isoflurane and sevoflurane on emergence time and PACU duration. METHODS: We reanalyzed data from 1498 adults who participated in a previous alternating intervention trial comparing isoflurane and sevoflurane. Patients, mostly having colorectal surgery, were assigned to either volatile anesthetic in 2-week blocks that alternated for half a year. Emergence time was defined as the time from minimum alveolar concentration fraction reaching 0.3 at the end of the procedure until patients left the operating room. PACU duration was defined from admission to the end of phase 1 recovery. Treatment effect was assessed using Cox proportional hazards regression, adjusted for imbalanced baseline variables. RESULTS: A total of 674 patients were given isoflurane, and 824 sevoflurane. Emergence time was slightly longer for isoflurane with a median (quartiles) of 16 minutes (12-22 minutes) vs 14 minutes (11-19 minutes) for sevoflurane, with an adjusted hazard ratio of 0.81 (97.5% CI, 0.71-0.92; P < .001). Duration in the PACU did not differ, with a median (quartiles) of 2.6 hours (2.0-3.6 hours) for isoflurane and 2.6 hours (2.0-3.7 hours) hours for sevoflurane. The adjusted hazard ratio for PACU discharge time was 1.04 (97.5% CI, 0.91-1.18; P = .56). CONCLUSIONS: Isoflurane prolonged emergence by only 2 minutes, which is not a clinically important amount, and did not prolong length of stay in the PACU. The more soluble and much less-expensive anesthetic isoflurane thus seems to be a reasonable alternative to sevoflurane.

Replacement of Fascia Iliaca Catheters with Continuous Erector Spinae Plane Blocks Within a Clinical Pathway Facilitates Early Ambulation After Total Hip Arthroplasty.

OBJECTIVE: The optimal continuous peripheral nerve block (CPNB) technique for total hip arthroplasty (THA) that maximizes both analgesia and mobility is unknown. Continuous erector spinae plane (ESP) blocks were implemented at our institution as a replacement for fascia iliaca (FI) catheters to improve our THA clinical pathway. We designed this study to test the hypothesis that this change will increase early postoperative ambulation for elective primary THA patients. METHODS: We identified all consecutive primary unilateral THA cases six months before and six months after the clinical pathway change to ESP catheters. All other aspects of the THA clinical pathway and multimodal analgesic regimen including perineural infusion protocol did not change. The primary outcome was total ambulation distance (meters) on postoperative day 1. Other outcomes included total ambulation on postoperative day 2, combined two-day ambulation distance, pain scores, opioid consumption, inpatient length of stay, and minor and major adverse events. RESULTS: Eighty-eight patients comprised the final sample (43 FI and 45 ESP). Postoperative day 1 total ambulation distance was greater for the ESP group compared with the FI group (median [10th-90th percentiles] = 24.4 [0.0-54.9] vs 9.1 [0.7-45.7] meters, respectively, P = 0.036), and two-day ambulation distance was greater for the ESP group compared with the FI group (median [10th-90th percentiles] = 68.6 [9.0-128.0] vs 46.6 [3.7-104.2] meters, respectively, P = 0.038). There were no differences in pain scores, opioid use, or other outcomes. CONCLUSIONS: Replacing FI catheters with continuous ESP blocks within a clinical pathway results in increased early ambulation by elective primary THA patients.

Arterial Catheters for Early Detection and Treatment of Hypotension During Major Noncardiac Surgery: A Randomized Trial.

BACKGROUND: Continuous blood pressure monitoring may facilitate early detection and prompt treatment of hypotension. We tested the hypothesis that area under the curve (AUC) mean arterial pressure (MAP) <65 mm Hg is reduced by continuous invasive arterial pressure monitoring. METHODS: Adults having noncardiac surgery were randomly assigned to continuous invasive arterial pressure or intermittent oscillometric blood pressure monitoring. Arterial catheter pressures were recorded at 1-minute intervals; oscillometric pressures were typically recorded at 5-minute intervals. We estimated the arterial catheter effect on AUC-MAP <65 mm Hg using a multivariable proportional odds model adjusting for imbalanced baseline variables and duration of surgery. Pressures <65 mm Hg were categorized as 0, 1-17, 18-91, and >91 mm Hg × minutes of AUC-MAP <65 mm Hg (ie, no hypotension and 3 equally sized groups of increasing hypotension). RESULTS: One hundred fifty-two patients were randomly assigned to arterial catheter use and 154 to oscillometric monitoring. For various clinical reasons, 143 patients received an arterial catheter, while 163 were monitored oscillometrically. There were a median [Q1, Q3] of 246 [187, 308] pressure measurements in patients with arterial catheters versus 55 (46, 75) measurements in patients monitored oscillometrically. In the primary intent-to-treat analysis, catheter-based monitoring increased detection of AUC-MAP <65 mm Hg, with an estimated proportional odds ratio (ie, odds of being in a worse hypotension category) of 1.78 (95% confidence interval [CI], 1.18-2.70; P = .006). The result was robust over an as-treated analysis and for sensitivity analyses with thresholds of 60 and 70 mm Hg. CONCLUSIONS: Intraoperative blood pressure monitoring with arterial catheters detected nearly twice as much hypotension as oscillometric measurements.

The use of extended release bupivacaine with transversus abdominis plane and subcostal anterior quadratus lumborum catheters: A retrospective analysis of a novel technique.

BACKGROUND AND AIMS: Liposomal bupivacaine (LB) is a formulation of local anesthetic that may exert analgesia over a prolonged period. Anecdotal use of LB suggests benefit and prolonged analgesia when used to supplement infiltration blocks. Our aim was to test the effect of a bolus of LB delivered through a nerve catheter in two types of interfascial plane blocks (transversus abdominis plane and anterior subcostal quadratus lumborum). The effect was evaluated through patient self-reporting of postsurgical pain up to 48 postoperative hours. MATERIAL AND METHODS: Medical records of adult postoperative patients who received LB in a peripheral nerve catheter were followed retrospectively and analysed for pain scores and spread of dermatomal numbness over 48 h following the postoperative dose. A chart review of patients who qualified between June 2015 and March 2017 was performed, and clinical data were obtained from the institutional Perioperative Health Documentation System. RESULTS: Pain scores decreased following LB bolus, and all patients reported efficient block analgesia after bolus injection. Dermatomal numbness decreased gradually and was minimal by 48 h following bolus. CONCLUSION: LB can be injected through a peripheral nerve catheter to prolong analgesia after catheter removal.

Real-time Ultrasound-Guided Lumbar Epidural with Transverse Interlaminar View: Evaluation of an In-Plane Technique.

OBJECTIVE: The anatomical landmarks method is currently the most widely used technique for epidural needle insertion and is faced with multiple difficulties in certain patient populations. Real-time ultrasound guidance has been recently used to aid in epidural needle insertion, with promising results. Our aim was to test the feasibility, success rate, and satisfaction associated with a novel real-time ultrasound-guided lumbar epidural needle insertion in the transverse interlaminar view. DESIGN: Prospective descriptive trial on a novel approach. SETTING: Operating room and preoperative holding area at a tertiary care hospital. SUBJECTS: Adult patients presenting for elective open prostatectomy and planned for surgical epidural anesthesia. METHODS: Consented adult patients aged 30-80 years scheduled for open prostatectomy under epidural anesthesia were enrolled. Exclusion criteria included allergy to local anesthetics, infection at the needle insertion site, coagulopathy, and patient refusal. A curvilinear low-frequency (2-5 MHz) ultrasound probe and echogenic 17-G Tuohy needles were used by one of three attending anesthesiologists. Feasibility of epidural insertion was defined as a 90% success rate within 10 minutes. RESULTS: Twenty-two patients were enrolled into the trial, 14 (63.6%) of whom found the process to be satisfactory or very satisfactory. The median time to perform the block was around 4.5 minutes, with an estimated success rate of 95%. No complications related to the epidural block were observed over the 48 hours after the procedure. CONCLUSIONS: We demonstrate the feasibility of a novel real-time ultrasound-guided epidural with transverse interlaminar view.

Association of Neuraxial Anesthesia With Postoperative Venous Thromboembolism After Noncardiac Surgery: A Propensity-Matched Analysis of ACS-NSQIP Database.

BACKGROUND: Neuraxial anesthesia improves components of the Virchow's triad (hypercoagulability, venous stasis, and endothelial injury) which are key pathogenic contributors to venous thrombosis in surgical patients. However, whether neuraxial anesthesia reduces the incidence of venous thromboembolism (VTE) remain unclear. We therefore tested the primary hypothesis that neuraxial anesthesia reduces the incidence of 30-day VTE in adults recovering from orthopedic surgery. Secondarily, we tested the hypotheses that neuraxial anesthesia reduces 30-day readmission, 30-day mortality, and the duration of postoperative hospitalization. METHODS: Inpatient orthopedic surgeries from American College of Surgeons National Surgical Quality Improvement Program database (2011-2015) in adults lasting more than 1 hour with either neuraxial or general anesthesia were included. Groups were matched 1:1 by propensity score matching for appropriate confounders. Logistic regression model was used to assess the effect of neuraxial anesthesia on 30-day VTE, 30-day mortality, and readmission, while Cox proportional hazard regression model was used to assess its effect on length of stay. RESULTS: Neuraxial anesthesia decreased odds of 30-day VTE (odds ratio 0.85, 95% confidence interval, 0.78-0.95; P = .002) corresponding to number-needed-to-treat of 500. Although there was no difference in 30-day mortality, neuraxial anesthesia reduced 30-day readmission (odds ratio 0.90, 98.3% confidence interval, 0.85-0.95; P < .001) corresponding to number-needed-to-treat of 250 and had a shortened hospitalization (2.87 vs 3.11; P < .001). CONCLUSIONS: Neuraxial anesthesia appears to provide only weak VTE prophylaxis, but can be offered as an adjuvant to current thromboprophylaxis in high-risk patients.

The supra-iliac anterior quadratus lumborum block: a cadaveric study and case series.

PURPOSE: The local anesthetic injectate spread with fascial plane blocks and corresponding clinical outcomes may vary depending on the site of injection. We developed and evaluated a supra-iliac approach to the anterior quadratus lumborum (QL) block and hypothesized that this single injection might successfully block the lumbar and sacral plexus in cadavers and provide analgesia for patients undergoing hip surgery. METHODS: Ultrasound-guided bilateral supra-iliac anterior QL blocks were performed with 30 mL of India ink dye in six fresh adult cadavers. Cadavers were subsequently dissected to determine distribution of the dye. In five patients undergoing hip surgery, a unilateral supra-iliac anterior QL block with 25 mL ropivacaine 0.5% followed by a continuous catheter infusion was performed. Patients were clinically assessed daily for block efficacy. RESULTS: The cadaveric injections showed consistent dye involvement of the majority of the branches of the lumbar plexus, including the femoral nerve, lateral femoral cutaneous nerve, ilioinguinal nerve, and iliohypogastric nerve. The majority of cadaveric specimens (83%) also exhibited thoracic paravertebral spread of dye to the T10 level. No specimens showed L5 or sacral nerve root staining or caudal spread below L5. All patients had effective analgesia for total hip surgery and a T11-L3 sensory level following the initial bolus of local anesthetic as well as during the period of continuous catheter infusion. CONCLUSION: This cadaveric study and case series show that a supra-iliac approach to the anterior QL block involved T10--L3 nerve territories and dermatomal coverage with no sacral plexus spread. This technique may have clinical utility for analgesia in hip surgery.

RéSUMé: OBJECTIF: La diffusion de l'anesthésique local injecté lors de la réalisation d'un bloc du fascia et les résultats cliniques qui en découlent peuvent varier selon le site d'injection. Nous avons mis au point et évalué une approche supra-iliaque pour la réalisation d'un bloc du muscle carré des lombes antérieur (quadratus lomburum) et émis l'hypothèse que cette injection unique pourrait suffire à bloquer les plexus lombaire et sacral de cadavres, offrant ainsi une analgésie aux patients subissant une chirurgie de la hanche. MéTHODE: Des blocs bilatéraux du muscle carré des lombes antérieur ont été réalisés par approche supra-iliaque sous échoguidage à l'aide de 30 mL de teinture d'encre de Chine sur six cadavres adultes frais. Les cadavres ont par la suite été disséqués afin de déterminer la diffusion de la teinture. Nous avons réalisé un bloc unilatéral du muscle carré des lombes antérieur par approche supra-iliaque avec une solution de 25 mL de ropivacaïne 0,5 %, suivie d'une perfusion continue via cathéter, chez cinq patients subissant une chirurgie de la hanche. Une évaluation clinique quotidienne des patients a été réalisée afin de déterminer l'efficacité du bloc. RéSULTATS: Les injections sur les cadavres ont permis d'observer une diffusion constante de la teinture dans la majorité des branches du plexus lombaire, y compris dans le nerf fémoral, le nerf fémoral cutané latéral, le nerf ilio-inguinal et le nerf ilio-hypogastrique. Une diffusion paravertébrale thoracique de la teinture jusqu'au niveau T10 a également été retrouvée dans la majorité des spécimens cadavériques (83 %). Aucune coloration au niveau de la racine L5 ou des nerfs sacrés n'a été observée chez les spécimens, ni aucune diffusion caudale au-dessous de L5. Tous les patients ont reçu une analgésie efficace pour une arthroplastie totale de la hanche et obtenu un bloc sensitif au niveau T11­L3 après l'injection du bolus initial d'anesthésique local ainsi qu'au cours de la période de perfusion continue. CONCLUSION: Cette étude cadavérique et cette série de cas montrent qu'une approche supra-iliaque pour réaliser un bloc du muscle du carré des lombes antérieur est parvenue à atteindre les territoires nerveux T10-­L3 et avec couverture de ces dermatomes et ce, sans diffusion au niveau du plexus sacré. Cette technique pourrait avoir une utilité clinique pour l'analgésie en cas de chirurgie de la hanche.

Subcostal approach to anterior quadratus lumborum block for pain control following open urological procedures.

In the case of open urological surgeries, analgesic coverage at mid thoracic dermatomal levels is required. As shown in cadaveric studies, the site of QL block injection is an important determinant of the extent of dye spread and presumably local anesthetic dermatomal coverage. In this case series, we evaluated dermatomal blockade and analgesic efficacy of a subcostal approach to anterior QL block following open urological surgeries. Twenty-two adult patients undergoing renal transplant surgery (60%) and open nephrectomy (40%) received unilateral ultrasound-guided subcostal anterior QL block with catheter insertion. Sensory level, pain score (numeric rating scale, NRS), local anesthetic consumption, and opioid consumption (morphine equivalent dose, MED) were assessed daily for 3 days. The block achieved sensory blockade between T6-7 and L1-2. The most frequently affected dermatomes were T8 -T12 and the number of blocked segments was 3 (mean 2.8). The median (interquartile range Q1, Q3) of NRS pain score was 3.7 (2.8-5.5), 3.3 (2.4-4.7), 2.9 (1.9-3.6), and 2.3 (1.0-4.2) on POD0, POD1, POD2, and POD3, respectively. Our preliminary data showed that the subcostal approach to anterior QL block provides appropriate thoracic dermatome level needed for analgesia following open urological surgical procedures between T6-7 and L1-2.

Use of colour Doppler and M-mode ultrasonography to confirm the location of an epidural catheter - a retrospective case series.

PURPOSE: Epidural anesthesia and analgesia has a reported failure rate ranging from 13% to 32%. We describe a technique using colour Doppler and M-mode ultrasonography to determine the position of the epidural catheter after placement in adults. METHODS: This retrospective review included 37 adult patients who received postoperative epidural analgesia and underwent technically difficult epidural catheter placement. The demographic characteristics, type of surgery, use of ultrasonography, method of insertion, intervertebral level, and success of epidural localization using colour Doppler were noted for each patient. Pain scores on postoperative day 1 and the presence of a patchy block were also reviewed. RESULTS: Colour Doppler study helped to indicate the catheter's path from the skin to the epidural space during saline injection in 33 patients (89%). Saline flow within the epidural space (catheter tip confirmation) was successfully detected with colour Doppler in 25 patients (67.5%) and with M-mode ultrasonography in 28 patients (75%). Appropriate dermatomal analgesia was noted in 35 patients (94.5%) during local anesthetic infusion. CONCLUSION: Our preliminary data suggest the feasibility of using colour Doppler and M-mode ultrasonography to confirm proper epidural catheter placement.

Perioperative epidural analgesia is not associated with increased survival from renal cell cancer, but overall survival may be improved: a retrospective chart review.

PURPOSE: We investigated the possible association between perioperative epidural and both cancer-specific survival (CSS) and overall survival (OS) in patients undergoing partial or radical nephrectomy for localized renal cell carcinoma (RCC). METHODS: A retrospective chart review was performed on patients who underwent complete surgical resection of localized RCC from 1994-2008 at our institution. Baseline demographics and pathological and survival data were collected. Patients with clinically or pathologically positive lymph nodes or metastatic disease at the time of surgery were excluded. Patients with pathologically positive surgical margins were also excluded. Patients were divided into two groups, systemic analgesia and epidural analgesia. Multivariable Cox regression analysis was used to determine CSS and OS, and survival curves were generated using the Kaplan-Meier method. RESULTS: Four hundred thirty-eight patients were included in the analysis. Baseline characteristics of both groups were similar. Median follow-up was 77 months. On multivariable analysis, patient age (hazard ratio [HR], 1.04; 95% confidence interval [CI], 1.02 to 1.07), epidural status (HR, 0.5; 95% CI, 0.4 to 0.8), year of surgery (HR, 0.9; 95% CI, 0.89 to 0.95), and pathologic T-stage (pT-stage) ≥ 2 (pT-stage2: HR, 2.2; 95% CI, 1.2 to 4.1 and pT-stage3: HR, 3.1; 95% CI, 2.0 to 4.7) were independent predictors of OS. Nevertheless, epidural status did not significantly predict CSS (P = 0.73), while T-stage and year of surgery maintained their respective predictive significance. Tumour grade did not significantly affect OS or CSS. CONCLUSIONS: Our retrospective analysis suggests that epidural at the time of surgical excision of localized RCC does not significantly impact CSS. Nevertheless, use of epidural was associated with significantly improved OS. Future prospective clinical and laboratory studies are warranted in order to characterize these associations further and determine the underlying mechanisms.

Injectate spread following anterior sub-costal and posterior approaches to the quadratus lumborum block: A comparative cadaveric study.

BACKGROUND: The dermatomal level of analgesia achieved with quadratus lumborum blocks varies according to the location of injection. The most commonly used approaches are either at the postero-lateral aspect or anterior to the quadratus lumborum muscle. OBJECTIVE: To determine whether the site of injection of contrast dye around the quadratus lumborum muscle of cadavers affects the extent and mechanism of dye spread. DESIGN: Observational human cadaver study. SETTING: Cleveland Clinic cadaveric laboratory. PARTICIPANTS: Six fresh human cadavers. INTERVENTIONS: The cadavers received either a posterior quadratus lumborum block or an anterior subcostal quadratus lumborum block on each side. MAIN OUTCOME MEASURES: Cadavers were dissected to determine the extent of dye spread. RESULTS: The posterior quadratus lumborum block approach revealed consistently deep staining of the iliohypogastric, ilioinguinal, subcostal nerve, T11 to 12 and L1 nerve roots. In addition, staining of the middle thoracolumbar fascia was seen in all specimens but only variable staining of T10 nerve roots. The anterior subcostal quadratus lumborum block approach in all specimens demonstrated predictable deep staining of the iliohypogastric and ilioinguinal nerves, subcostal nerves, T11 to 12 and L1 nerve roots, and in addition traversing the arcuate ligaments to involve T9 to 12 nerve roots with variable staining of higher thoracic nerve roots. CONCLUSIONS: Our cadaveric study demonstrates that injection of dye on the posterior aspect of quadratus lumborum muscle led to injectate spread through the lateral and posterior abdominal wall but with limited cranial spread, whereas the anterior approach produced broader coverage of the lower to mid-thoracic region. Clinical translation of these findings to determine the practical significance is warranted.

Novel needle guide reduces time to perform ultrasound-guided femoral nerve catheter placement: A randomised controlled trial.

BACKGROUND: Ultrasound-guided nerve blocks have become the standard when performing regional nerve blocks in anaesthesia. Infiniti Plus (CIVCO Medical Solutions, Kalona, Iowa, USA) is a needle guide that has been recently developed to help clinicians in performing ultrasound-guided nerve blocks. OBJECTIVES: We tested the hypothesis that femoral nerve catheter placement carried out with the Infiniti Plus needle guide will be quicker to perform than without the Infiniti Plus. Secondary aims were to assess whether the Infiniti Plus needle guide decreased the number of block attempts and also whether it improved needle visibility. DESIGN: A randomised, controlled trial. SETTING: Cleveland Clinic, Cleveland, Ohio, USA. PATIENTS: We enrolled adult patients having elective total knee arthroplasty with a femoral nerve block and femoral nerve catheter. Patients, who were pregnant or those who had preexisting neuropathy involving the surgical limb, coagulopathy, infection at the block site or allergy to local anaesthetics were excluded. INTERVENTIONS: Patients were randomised into two groups to receive the ultrasound-guided femoral nerve catheter placement with or without the Infiniti Plus needle guide. MAIN OUTCOME MEASURES: The time taken to place the femoral nerve catheter, the number of attempts, the success rate and needle visibility were recorded. We used an overall α of 0.05 for both the primary and secondary analyses; the secondary analyses were Bonferroni corrected to control for multiple comparisons. RESULT: The median (interquartile range Q1 to Q3) time to perform the femoral nerve catheter placement was 118 (100 to 150) s with Infiniti Plus and 177 (130 to 236) s without Infiniti Plus. Infiniti Plus significantly reduced the time spent performing femoral nerve catheterisation, with estimated ratio of means [(95% confidence interval), P value] of 0.67 [(0.60 to 0.75), P < 0.001] with Infiniti Plus compared with no Infiniti Plus. However, Infiniti Plus had no effect on the odds of a successful femoral nerve catheter placement, number of attempts or percentage of perfect needle visibility. CONCLUSION: We found that the use of Infiniti Plus decreased the median time to successfully place a femoral nerve catheter by 33% compared with not using Infiniti Plus. This difference may be more apparent to clinicians undertaking this procedure less often or by those in training as our team was very experienced, had been trained in the technique and was working in a hospital with a large caseload. TRIAL REGISTRATION: Clinicaltrials.gov identifier: NCT02080481.

Localization of epidural space: A review of available technologies.

Although epidural analgesia is widely used for pain relief, it is associated with a significant failure rate. Loss of resistance technique, tactile feedback from the needle, and surface landmarks are traditionally used to guide the epidural needle tip into the epidural space (EDS). The aim of this narrative review is to critically appraise new and emerging technologies for identification of EDS and their potential role in the future. The PubMed, Cochrane Central Register of Controlled Clinical Studies, and Web of Science databases were searched using predecided search strategies, yielding 1048 results. After careful review of abstracts and full texts, 42 articles were selected to be included. Newer techniques for localization of EDS can be broadly classified into techniques that (1) guide the needle to the EDS, (2) identify needle entry into the EDS, and (3) confirm catheter location in EDS. An ideal method should be easy to learn and perform, easily reproducible with high sensitivity and specificity, identifies inadvertent intrathecal and intravascular catheter placements with ease, feasible in perioperative setting and have a cost-benefit advantage. Though none of them in their current stages of development qualify as an ideal method, many show tremendous potential. Some techniques are useful in patients with difficult spinal anatomy and infants, and thus are complementary to traditional methods. In addition to improving the existing technology, future research should aim at proving the superiority of these techniques over traditional methods, specifically regarding successful EDS localization, better safety profile, and a favorable cost-benefit ratio.

Development of technologies for placement of perineural catheters.

Continuous peripheral nerve block (CPNB) success is largely dependent on placement of the catheter close enough to the nerve to allow effective and sustained analgesia following painful surgeries with a minimum volume of local anesthetic. One of the most common problems associated with CPNB involves accurate placement of the catheter tip, migration, and dislodgement of the catheter. This is of increasing importance now that catheters are left in place for prolonged periods of time to provide postoperative analgesia, and patients with peripheral nerve catheters are being discharged home with ambulatory pumps. In response to the challenges of providing safe, effective, and consistently reliable analgesia, research and development in this field is expanding rapidly. This review article presents results from recent publications addressing the subject of peripheral nerve catheter localization.

A nomogram for predicting the need for sciatic nerve block after total knee arthroplasty.

PURPOSE: Sciatic nerve block (SNB) is commonly performed in combination with femoral nerve block (FNB) for postoperative analgesia following total knee arthroplasty (TKA). Despite the fact that 10-20 % of TKA patients require SNB for postoperative posterior knee pain, there are no existing studies that suggest a model to predict the need for SNB. The aim of our study was to develop a prediction tool to measure the likelihood of patients undergoing TKA surgery requiring a postoperative SNB. METHODS: With institutional review board approval, we obtained data from the electronic medical record of patients who underwent TKA at the Cleveland Clinic. A multivariable logistic regression was used to estimate the probability of requiring a postoperative SNB. Clinicians selected potential predictors to create a model, and the potential nonlinear association between continuous predictors and SNB was assessed using the restricted cubic spline model. RESULTS: In total 6279 TKA cases involving 2329 patients with complete datasets were used for building the prediction model, including 276 (12 %) patients who received a postoperative SNB and 2053 (88 %) patients who did not. The estimated C statistic of the prediction model was 0.64. The nomogram is used by first locating the patient position on each predictor variable scale, which has corresponding prognostic points. The cut-off of 11.6 % jointly maximizes the sensitivity and specificity. CONCLUSION: This is the first study to be published on SNB prediction after TKA. Our nomogram may prove to be a useful tool for guiding physicians in terms of their decisions regarding SNB.