Does the approach influence the success rate for ultrasound-guided rectus sheath blocks? An anatomical case series

The Hypoechoic Triangle: A New Sonographic Landmark for Rectus Sheath Block

Rectus sheath blocks can provide analgesia for upper abdominal midline incisions. These blocks can be placed on patients who are anticoagulated, supine, and under general anesthesia. However, block success rates remain low, presumably because of the difficulty of placing local anesthetic between the correct fascial layers. Here we characterize a hypoechoic triangle with sonography, an anatomic space between adjacent rectus abdominis segments that can be accessed for easier needle tip and catheter placement. This approach could reduce reliance on hydrodissection to correctly identify the potential space and instead improve block efficacy by offering providers a discrete target for local anesthesia.

The Spread Distance of Local Anesthetics in the Rectus Sheath Block in Children Aged 0-8 Years: A Retrospective Study

Background The spread distance of local anesthetic (LA) in the rectus sheath block (RSB) should cover the planned surgical incision. However, there is limited data regarding the spread distance that can be covered by a certain volume in children. In this study, we aimed to investigate the spread distance of a particular volume of LA from a single injection point. Methodology This study included children aged 0-8 years (n = 41) who underwent umbilical or epigastric hernia repair, laparoscopic surgery, and surgeries via small midline incisions. The spread distances, which were measured via ultrasound guidance immediately after the block to ensure coverage of the entire planned surgical incision, were obtained from prospectively collected data about RSB. The spread distances in the craniocaudal direction on the right and left sides were compared and assessed for correlations with age, weight, LA volume, and sex. The need for a supplemental dose of LA in case of an incision exceeding the spread distance was also obtained from the records. Results The spread distances in the cranial and caudal directions from the injection point were 3.28 ± 1.04 cm and 3.74 ± 1.35 cm on the right (p = 0.066) and 3.44 ± 1.02 cm and 3.44 ± 1.33 cm on the left (p > 0.999), respectively. The total spread distances in the craniocaudal direction on the right and left were 5.55 ± 0.95 cm and 5.72 ± 1.28 cm in patients aged 0-2 years and 7.25 ± 1.92 cm and 7.39 ± 1.81 cm in patients aged at 2-8 years, respectively. The increase in the spread distance correlated with age, weight, and LA volume. None of the patients required a supplemental dose of LA, as the single-point injections covered the planned surgical incisions in all patients. Conclusions Similar spread distances in the cranial and caudal directions from a single injection point can be obtained with 0.5 mL/kg of the LA in 0-8-year-old children. The total spread distance in the craniocaudal direction was approximately 5 cm and 7 cm in children aged 0-2 years and 2-8 years, respectively.

Evaluating Patterns of Injectate Spread After Rectus Sheath Block: A Cadaveric Dissection Study

INTRODUCTION

This cadaveric dye study assesses the effect of volume and number of injections on the spread of solution after ultrasound-guided rectus sheath injections. In addition, this study evaluates the impact of the arcuate line on solution spread.

MATERIALS AND METHODS

Ultrasound-guided rectus sheath injections were performed on seven cadavers on both sides of the abdomen, for a total of 14 injections. Three cadavers received one injection of 30 mL of a solution consisting of bupivacaine and methylene blue at the level of the umbilicus. Four cadavers received two injections of 15 mL of the same solution, one midway between the xiphoid process and umbilicus and one midway between the umbilicus and pubis.

RESULTS

Six cadavers were successfully dissected and analyzed for a total of 12 injections, while one cadaver was excluded due to poor tissue quality that was inadequate for dissection and analysis. There was a significant spread of solution with all injections caudally to the pubis without limitation by the arcuate line. However, a single 30 mL injection showed inconsistent spread to the subcostal margin in four of six injections, including in a cadaver with an ostomy. A double injection of 15 mL showed consistent spread from xiphoid to pubis in five of six injections, except in a cadaver with a hernia.

CONCLUSIONS

Injections deep to the rectus abdominis muscle, using the same technique as an ultrasound-guided rectus sheath block, achieve spread along a large and continuous fascial plane without limitation by the arcuate line and may provide coverage of the entire anterior abdomen. A large volume is necessary for complete coverage and spread is improved with multiple injections. We suggest that two injections with a total volume of at least 30 mL per side may be needed to achieve adequate coverage in the absence of preexisting abdominal abnormalities.

OUP accepted manuscript

Background

Rectus sheath catheter analgesia (RSCA) and thoracic epidural analgesia (TEA) are both used for analgesia following laparotomy. The aim was to compare the analgesic effectiveness of RSCA with TEA after laparotomy for elective colorectal and urological surgery.

Methods

Patients undergoing elective midline laparotomy were randomized in a non-blinded fashion to receive RSCA or TEA for postoperative analgesia at a single UK teaching hospital. The primary quantitative outcome measure was dynamic pain score at 24 h after surgery. A nested qualitative study (reported elsewhere) explored the dual primary outcome of patient experience and acceptability. Secondary outcome measures included rest and movement pain scores over 72 h, functional analgesia, analgesia satisfaction, opiate consumption, functional recovery, morbidity, safety, and cost-effectiveness.

Results

A total of 131 patients were randomized: 66 in the RSCA group and 65 in the TEA group. The median (interquartile range; i.q.r.) dynamic pain score at 24 h was significantly lower after TEA than RSCA (33 (11–60) versus 50.5 (24.50–77.25); P = 0.018). Resting pain score at 72 h was significantly lower after RSCA (4.5 (0.25–13.75) versus 12.5 (2–13); P = 0.019). Opiate consumption on postoperative day 3 (median (i.q.r.) morphine equivalent 17 (10–30) mg versus 40 (13.25–88.50) mg; P = 0.038), hypotension, or vasopressor dependency (29.7 versus 49.2 per cent; P = 0.023) and weight gain to day 3 (median (i.q.r.) 0 (−1–2) kg versus 1 (0–3) kg; P = 0.046) were all significantly greater after TEA, compared with RSCA. There were no significant differences between groups in other secondary outcomes, although more participants experienced serious adverse events after TEA compared with RSCA, which was also the more cost-effective.

Conclusions

TEA provided superior initial postoperative analgesia but only for the first 24 h. By 72 hours RSCA provides superior analgesia, is associated with a lower incidence of unwanted effects, and may be more cost-effective.

Rectus sheath block and emergency midline laparotomy at a hospital in Ethiopia: A prospective observational study

BACKGROUND

Midline laparotomy is associated with severe postoperative pain. Literature showed controversial results regarding the efficacy of the rectus sheath block.

METHODS

This is a prospective cohort study that recruits 30 patients in the rectus sheath block (RSB) group and 30 patients in the multimodal analgesia (MMA) group who underwent emergency midline laparotomy. The RSB was performed by an experienced anesthetist using a land-mark technique. Independent t-test and Mann-Whitney-U test were used for numeric data while Chi-Square or Fisher exact test was used for categorical variables. P-values < 0.05 were considered as statistically significant.

RESULTS

The numeric rating scale score at the recovery was significantly reduced in an RSB group with a p-value of 0.039. Postoperative numeric rating scale scores at 3rd, 6th, 12th, and 24th hours were statistically significantly lower in the RSB group. Postoperative tramadol consumption in 24 h was significantly lower with a p-value of 0.0001 for the rectus sheath group.

CONCLUSIONS

For midline laparotomy, adding a bilateral rectus sheath block at the end of the operation might be an effective postoperative analgesia option.