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

Performance of the ratio of posterior complex length to depth measured by ultrasound as a predictor of difficult spinal anesthesia for elective cesarean delivery: a prospective cohort study

PURPOSE

Ultrasound view of the interlaminar structure is likely to be associated with difficult spinal anesthesia (DSA), and a poor ultrasound view which cannot show the anterior and posterior complex predicts a difficult spinal technique. As our target site is the posterior complex, this study aimed to assess whether the ratio of posterior complex length to depth measured by ultrasound can predict DSA in cesarean delivery.

METHODS

Four anesthesiologists with 1-2 years of experience located and marked the puncture interspace using a traditional surface landmark. Subsequently, the ultrasound examiner located and measured the marked interspace via an oblique parasagittal ultrasound scan. The anesthesiologists, who were blinded to the ultrasound results, performed spinal anesthesia using a 25-gauge Whitacre spinal needle. The total number of attempts, including skin punctures and needle passes, was recorded and the DSA was defined as 10 unsuccessful attempts. A multivariable logistic regression analysis was used to determine the independent predictors, and receiver operating characteristic curves were constructed to evaluate the performance of the ratio of posterior complex length to depth for predicting DSA.

RESULTS

A total of 397 cesarean delivery parturients with successfully measured posterior complex were included in the analysis. DSA occurred in 64 parturients (16.1%). Reduced length [odds ratio (OR) = 0.010, 95% confidence interval (CI), 0.002-0.062, P < 0.001] and increased depth [OR = 6.127, 95% CI, 2.671-14.056, P < 0.001] of the posterior complex were independently predictive of DSA compared with body mass index, abdominal circumference, and palpable surface landmarks. The ratio of posterior complex length to depth for predicting DSA had an area under the curve of 0.86 (95% CI, 0.82-0.90). The optimal cutoff was 0.23, with a sensitivity of 86% (95% CI, 74-93%) and specificity of 72% (95% CI, 67-77%).

CONCLUSION

The ratio of posterior complex length to depth measured by ultrasound demonstrated a considerable accuracy in predicting DSA for inexperienced anesthesiologists. A higher ratio at ultrasound is an indication to evaluate the optimal puncture body position and interspace in the clinic practice.

CLINICAL TRIAL REGISTRATION

ChiCTR2200065171 https://www.chictr.org.cn/showproj.html?proj=180855.

Comparison of neuraxial acoustic target window of the spine among rider sitting, cross leg, hamstring stretch, and classical sitting position: An observational study

Background and Aims

To compare ultra-sonographic dimensions of acoustic target window of the spine in the participants at four different sitting positions namely cross leg sitting (CLP), hamstring stretch (HSP), classical sitting (CSP) and riders sitting position (RSP). The primary objective of this study was to measure the neuraxial acoustic target window (defined as interlaminar distance between L3-L4 lamina). The secondary objective was to compare ultra-sonographic measurements of the depth of ligamentum flavum from the skin, and to compare the diameter of intrathecal space and comfort score in the four different sitting positions.

Material and Methods

This study is a prospective observational study. Eighty participants were included and positioned in four different sitting positions to perform an ultra-sonographic scan and measure various parameters of the acoustic neuraxial window. The interlaminar distance, the distance of skin from the ligamentum flavum, and the diameter of the spinal canal or intrathecal space was measured in the L3-L4 intervertebral space in different positions.

Results

The mean value of interlaminar distance among four sitting positions was ranging from 1.40 cm to 1.44 cm (P value 0.725.) The distance of ligamentum flavum from skin and diameter of intrathecal space was also comparable in all the groups. The comfort score in CSP was significantly better when compared to other groups with a median score of 4 (P value < 0.001).

Conclusions

There is no statistically significant difference in interlaminar distance in various sitting positions. All four positions are equally effective and can be used as an alternative to spinal/epidural intervention, but the CSP came out to be the most comfortable and more emphasis should be given to the comfort as it increases the chance of success rate of the procedure.

Correlation of preprocedural ultrasound estimated epidural depths in transverse median and posterior sagittal oblique view and body mass index with procedural epidural depths in patients scheduled for surgery under lumbar epidural anaesthesia

Background and Aims:

Preprocedural lumbar ultrasound (US) is employed for the estimation of epidural depth (ED). This study observed the correlation of preprocedural ED in transverse median (TM), parasagittal oblique (PSO) view, and body mass index (BMI) with procedural ED.

Methods:

In a prospective study, 100 female patients, aged 40–65 years, with American Society of Anesthesiologists physical status I/II, BMI 18.5–30 kg m−² scheduled for surgeries under lumbar epidural blocks were included. In the TM group, preprocedural ultrasonography (USG) was performed in TM view and ED was calculated, whereas in the PSO group, the paramedian sagittal view was used and corresponding markings were done for epidural needle insertion in the midline and paramedian planes, respectively. The primary outcome was the correlation of procedural ED and preprocedural ED in TM and PSO views, respectively. The secondary outcomes included correlation of procedural ED with BMI, comparability of preprocedural, and procedural ED in TM and PSO views. Statistical analysis was performed using Statistical Package for the Social Sciences (SPSS) v19.0 (International Business Machines, USA).

Results:

The preprocedural and procedural ED was less in the TM group (4.43 ± 0.75 and 4.44 ± 0.75 cm) in comparison to those in the PSO group (4.86 ± 0.53, 4.90 ± 0.54; P = 0.001). Strong correlation was observed in preprocedural and procedural ED [r² = 0.996 and 0.995]. The procedural ED had strong correlation with BMI [r² = 0.600, P = 0.001] in the TM group, and weak correlation [r² = 0.367] in the PSO group [P = 0.01]. The procedural ED was comparable to preprocedural ED in TM and PSO groups.

Conclusion:

Preprocedural US scanning provides an accurate estimate of actual EDs in TM and PSO view.

Abdominal girth has a strong correlation with actual and ultrasound estimated epidural depth

Background/aim

This study aimed to assess the correlations of actual epidural depth (ND) and ultrasound estimated epidural depth in the paramedian sagittal oblique plane (ED/PSO) and transverse median plane (ED/TM) with the abdominal girth (AG), body mass index (BMI), and weight of patients.

Materials and methods

One hundred and thirty patients of either sex scheduled for unilateral inguinal hernia repair were enrolled. ED/PSO and ED/TM were assessed with a 2–5 MHz curved array probe at the L3–4 intervertebral space. The epidural needle was marked with a sterile marker upon locating the epidural space. The ND was assessed by measuring the distance from the sterile marker to the tip of the epidural needle with a linear scale. Anthropometric measures of the patients were recorded.

Results

ED/PSO was 49.6 ± 7.9 mm, ED/TM was 49.5 ± 7.9 mm, and ND was 50.0 ± 8.0 mm. AG was 99.8 ± 12.9 cm. The Pearson correlation coefficient between ND and ED/PSO was 0.997 and with ED/TM was 0.996 (P < 0.001 for both). Pearson correlation coefficients for ND with AG, BMI, and weight were 0.757, 0.547, and 0.638, respectively (P < 0.001 for all).

Conclusion

AG, weight, and BMI have strong correlations with ND.

Feasibility of ultrasound-guided lumbar epidural access using paramedian transverse scanning with the needle in-plane: a comparison with paramedian sagittal scanning

BACKGROUND AND OBJECTIVES

The present study was designed to compare the feasibility of ultrasound (US)-guided lumbar epidural access using paramedian sagittal scanning (PMSS) and paramedian transverse scanning (PMTS) approaches.

METHODS

Fifty patients undergoing surgery of the lower extremities were randomly allocated into 2 groups. The patients in PMSS group received PMSS-guided in-plane epidural access, whereas patients in PMTS group received PMTS-guided in-plane epidural access. The US visibility of neuraxial structures and of Tuohy needle during US scout scan, procedure duration, the number of attempts to access epidural space, Tuohy needle puncture depth in the epidural space, and extent of sensory block after spinal block between two groups were compared.

RESULTS

The US visibility of Tuohy needle and neuraxial structures was comparable between two groups. There was an overall decrease in procedure duration in the PMTS group relative to the PMSS group (360 ± 42 vs. 490 ± 38 s). The number of attempts needed to access the epidural space in PMSS group was significantly higher than in PMTS group. Distances between the epidural space and the puncture site in PMSS group and PMTS group showed a significant difference (7.13 ± 0.67 vs. 5.24 ± 0.21 cm). No significant differences in the extent of sensory block after spinal block were observed.

CONCLUSIONS

We found that PMTS approach was superior as a means of achieving epidural access relative to the PMSS approach, since PMTS approach can be conducted more quickly given shorter path of the needle and less times needed for epidural access during this procedure.

CLINICAL TRIAL REGISTRATION

Chinese Clinical Trial Registry, clinical trial number ChiCTR1800015815, date of registration April 24, 2018.

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

EXECUTIVE SUMMARY

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.