Usefulness of a pre-procedure ultrasound scanning of the lumbar spine before epidural injection in patients with a presumed difficult puncture: A randomized controlled trial

Efficacy and safety of ultrasound-guided versus landmark-guided neuraxial puncture: a systematic review, network meta-analysis and trial sequential analysis of randomized clinical trials

BACKGROUND

Data suggest that preprocedural ultrasound may improve the efficacy of central neuraxial puncture. However, it remains uncertain whether these findings can be extended to various clinical scenarios, including diverse patient populations and the application of real-time ultrasound guidance. Additionally, it is unclear whether ultrasound-guided techniques improve safety and patient-centered outcomes.

METHODS

We searched six databases for randomized trials of adult patients undergoing neuraxial puncture, comparing real-time ultrasound, preprocedural ultrasound, and landmark palpation for efficacy, safety and patient-centered outcomes. Our primary outcome was a failed first-attempt neuraxial puncture. After two-person screening and data extraction, meta-analyses were conducted and the Grading of Recommendations Assessment, Development and Evaluation approach was applied to assess the certainty of evidence.

RESULTS

Analysis of 71 studies involving 7153 patients, both real-time ultrasound (OR 0.30; 95% credible interval (CrI) 0.15 to 0.58; low certainty) and preprocedural ultrasound (OR 0.33; 95% CrI 0.24 to 0.44; moderate certainty) showed a significant reduction in the risk of a failed first neuraxial puncture. Real-time ultrasound had the best performance for preventing first-attempt failures (low certainty evidence). Although real-time ultrasound was also the leading method for reducing the risk of complete neuraxial puncture failure, the results did not show a statistically significant difference when compared with landmark palpation. Preprocedural ultrasound, however, significantly reduced the odds of complete puncture failure (OR 0.29; 95% CrI 0.11 to 0.61). These ultrasound-guided approaches also contributed to a reduction in certain complications and increased patient satisfaction without any other significant differences in additional outcomes. Trial sequential analysis confirmed that sufficient information was achieved for our primary outcome.

CONCLUSIONS

Ultrasound-guided neuraxial puncture improves efficacy, reduces puncture attempts and needle redirections, reduces complication risks, and increases patient satisfaction, with low to moderate certainty of evidence. Despite real-time ultrasound's high ranking, a clear superiority over preprocedural ultrasound is not established. These results could prompt anesthesiologists and other clinicians to reassess their neuraxial puncture techniques.

Comparative efficacy of ultrasound guidance or conventional anatomical landmarks for neuraxial puncture in adult patients: a systematic review and network meta-analysis

BACKGROUND

Preprocedural, real-time, and computer-aided three-dimensional ultrasound has been widely used for neuraxial puncture; however, the optimal guidance is unclear. We examined the comparative efficacy of three ultrasound guidance and anatomical landmarks for neuraxial puncture in adults.

METHODS

We searched for randomised controlled studies comparing the efficacy of ultrasound guidance and anatomical landmarks for neuraxial puncture in adults using electronic databases and unpublished studies. The primary outcomes were first-pass success and patient satisfaction. A random-effects network meta-analysis (NMA) was used.

RESULTS

We identified 74 eligible studies (7090 patients). Preprocedural ultrasound and real-time ultrasound-guided neuraxial puncture improved first-pass success compared with anatomical landmarks (risk ratio [RR] 1.6; 95% credible interval [CrI] 1.3-1.9; RR 1.9; 95% CrI 1.3-2.9, respectively, moderate confidence). Computer-aided ultrasound-guided neuraxial puncture also increased first-pass success (RR 1.8; 95% CrI 0.97-3.3, low confidence), although estimates were imprecise. However, real-time ultrasound-guided neuraxial puncture resulted in minimal difference in first-pass success compared with preprocedural ultrasound (RR 1.2; 95% CrI 0.8-1.8, moderate confidence). Preprocedural ultrasound improved patient satisfaction slightly compared with anatomical landmark use (standardised mean differences 0.28; 95% CrI 0.092-0.47, low confidence).

CONCLUSIONS

This NMA provides evidence supporting ultrasound-guided neuraxial puncture compared with use of anatomical landmarks, including indirect comparisons. Among the three ultrasound guidance methods, preprocedural ultrasound appears to be a better adjunctive option.

Retrospective analysis of predisposing factors for difficult lumbar punctures requiring image guidance in pediatric oncology patients

Success rates of lumbar punctures (LPs) in children are reportedly as low as 50%. In addition to procedural complications and failure, difficult LPs are a risk factor for traumatic LPs (TLPs), which can potentially affect diagnostic utility and alter treatment plans for pediatric oncology patients. To identify the intrinsic factors associated with technically difficult LPs in the pediatric oncology population, we performed a retrospective review of patients who required diagnostic imaging modalities for LP procedures at a single pediatric oncology institution between September 2008 and November 2018. We evaluated data from 64 LPs performed in 33 patients who were referred for image-guided LPs after undergoing technically difficult LPs that were unsuccessful using anatomic landmarks. In these cases, 96.9% of patients had at least one of the following intrinsic factors: body mass index (BMI) ≥ 25, anatomic spinal abnormalities, history of ≥ 5 previous LPs, age < 12 months, and history of back surgery. Elevated BMI was the most common factor associated with difficult LP (81.8%), followed by spinal abnormalities (51.5%), and history of ≥ 5 previous LPs (33.3%). Age < 12 months and history of back surgery were also associated with difficult LPs, but at a lower frequency. On the basis of these findings, we propose clinical recommendations for preprocedural identification of patients at risk of difficult LPs to reduce complications, including TLP, failure, and exposure to general anesthesia.

Conventional landmark palpation versus preprocedural ultrasound for neuraxial procedures in nonobstetric patients: A systematic review with meta-analysis and trial sequential analysis of randomised controlled trials

BACKGROUND

Central neuraxial modalities can occasionally be challenging to perform, particularly if the underlying anatomy is altered or obscured.

OBJECTIVES

To compare the efficacy, efficiency and the safety of preprocedural ultrasound to landmark palpation in the nonobstetric adult population.

DESIGN

Systematic review of randomised controlled trials with meta-analysis and trial sequential analysis.

DATA SOURCES

Systematic search of Central, CINAHL, Embase, Global Health, MEDLINE, Scopus and Web of Science to 13th February 2020.

ELIGIBILITY CRITERIA

Randomised controlled trials of nonobstetric adult patients having diagnostic and/or therapeutic neuraxial procedures using standard preprocedural ultrasound interpreted by the operator as the intervention and conventional landmark palpation as the comparator.

KEY DEFINITIONS

A skin puncture was defined as the insertion or reinsertion of the needle through the skin; needle redirection was the backward followed by the forward movement of the needle without its removal from the skin; first skin puncture referred to a single skin puncture with or without needle redirections; and first pass was a single skin puncture with no needle redirection.

RESULTS

In all, 18 randomised controlled trials with 1800 patients were included. The first pass success rate was not different between landmark and ultrasound methods [risk ratio 1.46; 95% confidence interval (CI), 0.99 to 2.16; P = 0.06, I2 = 76%; moderate quality of evidence] and the trial sequential analysis demonstrated the futility of further randomisation of patients in modifying this finding. Preprocedural ultrasound increased the total time taken (mean difference 110.8 s; 95% CI, 31.01 to 190.65; P = 0.006; I2 = 96%; moderate quality of evidence). Subgroup analyses revealed no influence of the predicted difficulty of the neuraxial procedure on outcomes. Compared with the landmark method, ultrasound increased the first skin puncture success rate (risk ratio 1.36; 95% CI, 1.18 to 1.57; P < 0.001; I2 = 70%), and decreased the need for three or more skin punctures (risk ratio 0.46; 95% CI, 0.33 to 0.64; P < 0.001; I2 = 29%) and the number of needle redirections (mean difference -1.24; 95% CI, -2.32 to -0.17; P = 0.020; I2 = 83). The incidence of bloody tap was reduced with the use of ultrasound (risk ratio 0.61; 95% CI, 0.40 to 0.93; P = 0.020; I2 = 42%).

CONCLUSIONS

The use of preprocedural ultrasound for neuraxial procedures in the nonobstetric adult population did not enhance the first pass success rate and increased the total time taken to a clinically insignificant extent. Improvement in secondary outcomes, including other markers of efficacy, should be interpreted with caution.

Predicting difficult spinal anesthesia: development of a neuraxial block assessment score

BACKGROUND

Spinal anesthesia is a commonly performed procedure with unpredictable difficulty. The objective of this study was to predict a difficult lumbar spinal anesthesia with clinical elements that are easy to collect.

METHODS

A questionnaire-based, observational study named NBA, conducted from February 2018 to June 2018. The questions regarded clinical elements and the eventual spinal anesthesia difficulty encountered. A total of 427 questionnaires were filled by the operators. The clinical elements were selected upon literature search and have been integrated with new ones. All the answers were recorded from the anesthesiologist performing the procedure.

RESULTS

The NBA Score was derived from a total number of 427 questionnaires. Among them, 26 patients had "previous history of difficult spinal anesthesia;" 277 had "spinous processes not visible;" 83 had "spinous processes not palpable;" 77 had "spinal deformities" and 28 had "previous spinal surgery" in the puncture area; 138 patients received lumbar spinal anesthesia in lateral position. There were 328 (76.8%) single puncture successes. Seventy-nine (18.5%) patients required more than one skin puncture to obtain a successful spinal anesthesia. 20 (4.7%) required an alternative anesthesia technique (general anesthesia). Multivariate analysis indicated that each element is a risk factors for difficult spinal anesthesia, except for previous spinal surgery.

CONCLUSIONS

The combination of more than one element increased the chance of a second skin puncture of more than 50%. This work proposes a simple clinical scoring system predicting the probability of a difficult spinal anesthesia.

Could preprocedural ultrasound increase the first-pass success rate of neuraxial anesthesia in obstetrics? A systematic review and meta-analysis of randomized controlled trials

Neuraxial anesthesia is a common practice in obstetrics. Evidence suggests that preprocedural ultrasound versus the conventional landmark location method accurately identifies a given intervertebral space and predicts the needle insertion depth required to reach the spinal canal. However, whether the preprocedural ultrasound examination improves the first-pass success (FPS) rate remains elusive. Major databases were systematically searched for all relevant studies published in English up to June 2019. Eighteen randomized controlled trials including 1844 patients were enrolled. The quality of eligible studies was assessed, and predefined outcomes were synthesized by meta-analysis. The primary results showed that preprocedural ultrasound increased the FPS rate in patients with predicted puncture difficulty but not in patients who were easily punctured. Preprocedural ultrasound reduced the number of redirections and punctures and decreased the incidence of vascular puncture and backache. There was no evidence of a reduction in failed punctures. We also noted that preprocedural ultrasound prolonged the identification time but not the procedure time. Thus, this systematic review provides evidence that preprocedural ultrasound does not improve the FPS rate of neuraxial anesthesia in patients who are easily palpated, although it increases the FPS rate in patients who are difficult to palpate.

Recommendations on the Use of Ultrasound Guidance for Adult Lumbar Puncture: A Position Statement of the Society of Hospital Medicine

When ultrasound equipment is available, along with providers who are appropriately trained to use it, we recommend that ultrasound guidance should be used for site selection of lumbar puncture to reduce the number of needle insertion attempts and needle redirections and increase the overall procedure success rates, especially in patients who are obese or have difficult-to-palpate landmarks. We recommend that ultrasound should be used to more accurately identify the lumbar spine level than physical examination in both obese and nonobese patients. We suggest using ultrasound for selecting and marking a needle insertion site just before performing lumbar puncture in either a lateral decubitus or sitting position. The patient should remain in the same position after marking the needle insertion site. We recommend that a low-frequency transducer, preferably a curvilinear array transducer, should be used to evaluate the lumbar spine and mark a needle insertion site. A high-frequency linear array transducer may be used in nonobese patients. We recommend that ultrasound should be used to map the lumbar spine, starting at the level of the sacrum and sliding the transducer cephalad, sequentially identifying the lumbar spine interspaces. We recommend that ultrasound should be used in a transverse plane to mark the midline of the lumbar spine and in a longitudinal plane to mark the interspinous spaces. The intersection of these two lines marks the needle insertion site. We recommend that ultrasound should be used during a preprocedural evaluation to measure the distance from the skin surface to the ligamentum flavum from a longitudinal paramedian view to estimate the needle insertion depth and ensure that a spinal needle of adequate length is used. We recommend that novices should undergo simulation-based training, where available, before attempting ultrasound-guided lumbar puncture on actual patients. We recommend that training in ultrasound-guided lumbar puncture should be adapted based on prior ultrasound experience, as learning curves will vary. We recommend that novice providers should be supervised when performing ultrasound-guided lumbar puncture before performing the procedure independently on patients.

Lumbar Ultrasonography for Obstetric Neuraxial Blocks: Sonoanatomy and Literature Review

Ultrasonography has gained popularity in recent years among anaesthesiologists and being used widely for regional blocks and central venous catheterization. Ultrasonography for neuraxial blocks was found beneficial especially for determining the correct needle insertion site and estimating the needle insertion depth of epidural space. In many recent studies, ultrasound guided epidural and spinal blocks have been evaluated among obstetric patients. Pre-procedural lumbar ultrasonography and real time ultrasound guidance for neuraxial blocks was the subject of these studies. We aimed to evaluate lumbar ultrasonography for obstetric neuraxial blocks. We describe the principles of lumbar ultrasound scanning techniques and present a practical review of lumbar sonoanatomy. We discuss the potential impact and benefits of the ultrasound-guided technique in improving obstetric neuraxial blocks and limitations of its use in clinical practice, based on previous studies.

Automatic Localization of the Needle Target for Ultrasound-Guided Epidural Injections

Accurate identification of the needle target is crucial for effective epidural anesthesia. Currently, epidural needle placement is administered by a manual technique, relying on the sense of feel, which has a significant failure rate. Moreover, misleading the needle may lead to inadequate anesthesia, post dural puncture headaches, and other potential complications. Ultrasound offers guidance to the physician for identification of the needle target, but accurate interpretation and localization remain challenges. A hybrid machine learning system is proposed to automatically localize the needle target for epidural needle placement in ultrasound images of the spine. In particular, a deep network architecture along with a feature augmentation technique is proposed for automatic identification of the anatomical landmarks of the epidural space in ultrasound images. Experimental results of the target localization on planes of 3-D as well as 2-D images have been compared against an expert sonographer. When compared with the expert annotations, the average lateral and vertical errors on the planes of 3-D test data were 1 and 0.4 mm, respectively. On 2-D test data set, an average lateral error of 1.7 mm and vertical error of 0.8 mm were acquired.

Lumbar epidural depth using transverse ultrasound scan and its correlation with loss of resistance technique: A prospective observational study in Indian population

Background and Objectives:

The objective of the present study was to evaluate the skin-epidural space distance as assessed by ultrasonography and conventional loss of resistance (LOR) technique and to find the correlation of epidural depth with body mass index (BMI).

Methods:

Ninety-eight patients of either sex, American Society of Anesthesiology I/II, BMI <30 kg/m² requiring lumbar epidural for surgery were enrolled. The epidural space was assessed with a curvilinear ultrasound (US) probe, 2–5 MHz, in the transverse plane at L3–L4 intervertebral space. Thereafter, the epidural depth from skin was assessed with conventional LOR method while performing the epidural. The needle depth (ND) was measured using a sterile linear scale, and any change in the needle direction or intervertebral space was noted.

Results:

The patients were demographically similar. Depth of epidural space measured by US depth (UD) was 3.96 ± 0.44 cm (range 3.18–5.44 cm) and by ND was 4.04 ± 0.52 cm (range 2.7–5.7 cm). The Pearson's correlation coefficient (r) between UD and ND was 0.935 (95% confidence interval: 0.72–0.92, r² = 0.874, P < 0.001), and Bland–Altman analysis revealed the 95% limits of agreement −0.494–0.652 cm.

Conclusion:

The present study demonstrates a good correlation between UD and ND and shows that the preprocedural US scan in transverse plane provides accurate needle entry site with a high success rate in single attempt for lumbar epidurals in patients with a BMI <30 kg/m².