Ultrasound-guided subparaneural popliteal sciatic nerve block: there is more to it than meets the eyes

Assessment in location of sciatic nerve between the ischial tuberosity and the greater trochanter of the femur: A cadaveric study

Background

The location description of the sciatic nerve (SN) of adult between the ischial tuberosity (IT) and the greater trochanter of the femur (GT) is inconsistent in publications, this impels us to investigate and measure the distance relationship with SN between IT and GT.

Methods

Thirty-one adult cadavers were dissected to investigate the distance relationship of SN with the posterior prominent position of the ischial tuberosity (ppIT), the medial edge of IT (mIT) and the lateral prominent position of GT (lGT).

Results

SN passed through the point of the junction of medial one-third and middle one-third of a length from ppIT to lGT, and the midpoint of a length from mIT to lGT from the average data of the total studied cadavers. From average data of female and male, the left SN passed through the point of the junction of the medial two-fifths and the lateral three-fifths of the length between mIT and lGT. Between ppIT and lGT, SN located in a range of proportions from 0.1 to 0.6 from medial to lateral. Between mIT and lGT, SN located in a range of proportions from 0.2 to 0.7 from medial to lateral and all SN passed through the middle third of the length.

Conclusions

Different bony landmarks draw different location descriptions of anatomic structure. In anatomic study and clinical practice, the utilized bony landmark should be clearly and accurately identified the reference point, inaccurate bony landmark can result in erroneous localization of the interested anatomic structure and lead to operation failure or iatrogenic injury.

Endovascular revascularization of critical limb ischemia: the role of ultrasound-guided popliteal sciatic nerve block for the procedural pain management

OBJECTIVES

To evaluate the impact of the ultrasound-guided popliteal sciatic nerve block (PSNB) for pain management during endovascular treatment of chronic limb-threatening ischemia (CLTI).

MATERIAL AND METHODS

From November 2020 to January 2022, 111 CLTI patients that underwent endovascular procedures were prospectively enrolled in this prospective single-arm interventional study. Ultrasound-guided PSNB was used for procedural pain control. Pain intensity was evaluated throughout the procedure (baseline, 10 min after the block, pain peak, and at the end of the procedure) with the visual analog scale (VAS).

RESULTS

Forty-six patients underwent above-the-knee revascularization (ATK), 20/111 below-the-knee (BTK) revascularization, 20/111 to both ATK and BTK revascularization. In 25 cases, no endovascular option was feasible at diagnostic angiography. The PSNB was effective in 96% of patients, with no need for further pain management with a statistically significant reduction (p < 0.0001) in the mean value of the VAS from 7.86 ± 1.81 (pre-procedural) to 2.04 ± 2.20 after 10 min from the block and up to 0.74 ± 1.43 at the end of the procedure (mean time 43 min). Only 1 complication related to the popliteal sciatic nerve block was registered (a temporary foot drop, completely resolved within 48 h). The time necessary to perform the block ranged between 4 and 10 min.

CONCLUSION

Ultrasound-guided PSNB is a feasible and effective method to manage patients with rest pain and increase comfort and compliance during endovascular procedures.

CLINICAL RELEVANCE STATEMENT

An ultrasound-guided popliteal sciatic nerve block is a safe, feasible, and effective technique to manage pain during endovascular treatment of chronic limb-threatening ischemia, especially in frail patients with multiple comorbidities who are poor candidates for deep sedoanalgesia or general anesthesia.

KEY POINTS

Endovascular treatment of CTLI may require long revascularization sessions in patients with high levels of pain at rest, which could be exacerbated during the revascularization procedure. The PSNB is routinely used for anesthesia and analgesia during foot and ankle surgery, but the experience with lower limb revascularization procedures is very limited and not included in any international guideline. Ultrasound-guided PSNB is a feasible and effective regional anesthesia technique to relieve procedural and resting pain. Because of its safety and availability, every interventional radiologist should know how to perform this type of loco-regional anesthesia.

Quantitative assessment of ultrasound-guided sciatic nerve block - A comparison of a single-point versus two-point injection technique: A randomised controlled, double-blinded trial

Background and Aims

Sciatic nerve block at the popliteal level for lower limb procedures provides unpredictable success rates even with ultrasonographic (USG) guidance. This study aimed to compare USG-guided single-point versus two-point injection techniques.

Methods

Sixty patients posted for foot surgeries under USG-guided sciatic nerve block were randomised into Group Single Point, receiving a single injection of 20 mL of 1.5% lignocaine with adrenaline just proximal to the sciatic nerve bifurcation, and Group Double Point, receiving two injections of 10 mL of 1.5% lignocaine with adrenaline, one at the point similar to the first group and a second injection 6 cm above the first point. Sensory blockade onset, time to complete sensory blockade, time to complete motor blockade, length of the nerve exposed and analgesia duration were evaluated. Statistical analysis was performed with Statistical Package for the Social Sciences (SPSS) statistics version 20 software.

Results

Double-point injection technique showed a significantly faster time to complete motor blockade [14.46 (9.93) min], increased length of nerve exposed to local anaesthetic [23.23 (7.209) cm] and extended duration of analgesia [420.40 (99.34) min] compared to the single-point injection technique [20.89 (12.62) min, 18.78 (5.95) cm and 344.28 (125.97) min, respectively]. The onset of sensory blockade and the time to complete sensory blockade were comparable between the two groups.

Conclusion

USG-guided popliteal sciatic nerve block with a double-point injection technique does not significantly shorten the time to complete the sensory block. However, the time to complete motor nerve block and duration of analgesia are prolonged significantly, which may be clinically beneficial for postoperative analgesia.

Global Status and Future Trends of Fascia and Pain Research in 2013-2022: Bibliometric Analysis Based on CiteSpace and VOSviewer

Background

Fascial pathological pain is the main type of chronic pain in older adults today, and studying the relationship between fascia and pain can help in the clinical search for effective treatments. However, in the face of the vast amount of research findings, there is no systematic assessment of the relationship between fascia and pain in a bibliometric analysis. Therefore, the purpose of this study is to analyze studies on fascia and pain using CiteSpace and VOSviewer to identify research hotspots and future directions.

Materials and Methods

A total of 744 papers related to fascia and pain from 2013 to 2022 were collected from the core collection database of Web of Science, and the authors, countries, institutions, keyword co-occurrence, keyword clustering, and keyword emergence were analyzed by CiteSpace and VOSviewer to construct a knowledge map.

Results

Literature publication has shown an overall upward trend over the past decade, but there have been some fluctuations. Carmelo Pirri, Caterina Fede, and Raffaele De Caro are the top three authors with the most articles. The United States, China, and Spain are major contributors to fascial and pain research. The University of Padua, Universidad Complutense and Harvard Medical School are leading institutions in this field. However, it is noteworthy that the collaboration between authors, countries and institutions is not active. Keyword analysis showed that hot spots and trends in research on fascia and pain focused on hot diseases, major interventions, and mechanism exploration.

Conclusion

This analysis identifies the most influential authors, institutions, and countries in the field of fascial and pain research and provides a reference for assessing their academic impact. The analysis of keywords and co-cited literature is useful for analyzing research hotspots and their evolution, as well as for predicting future trends.

Peripheral Nerve Blocks Associated With Shorter Length of Stay Without Increasing Readmission Rate for Ankle Open Reduction Internal Fixation in the Outpatient Setting: A Propensity-Matched Analysis

Peripheral nerve blocks (PNB) have become an important modality for pain management in ankle fracture surgery. Previous studies have reported their efficacy, but concerns with rebound pain and readmissions have been cited as possible deterrents. The purpose of this study was to evaluate the effects of PNB on hospital length of stay (LOS), narcotic intake, visual analog scale (VAS) for pain, and associated complications in patients undergoing outpatient ankle open reduction internal fixation (ORIF). Adult patients undergoing ankle ORIF were matched 2:1 (no block:block) using propensity-score matching. Preoperative patient characteristics and postoperative outcomes were compared between cohorts. VAS and total narcotic intake were evaluated for each of the first 3 postoperative 8-hour shifts. Narcotic medication was converted to morphine milligram equivalents (MME). Thirty-two patients who received PNB were matched to 64 patients who did not. The PNB group had lower VAS and MME during each of the 8-hour shifts after surgery: 0 to 8 hours (VAS 1.8 vs 6.3; MME 10.6 vs 77.9; p < .001), 8 to 16 hours (VAS 1.2 vs 5.9; MME 9.2 vs 28.2; p < .001), 16 to 24 hours (VAS 3.7 vs 6.2; MME 13.2 vs 24.2; p = .006 and 0.019). PNB had a shorter LOS (average 16.7 hours vs 26.8 hours; p < .001). There were no differences in rates of ED presentations after discharge, hospital readmissions, or complications between cohorts. Peripheral nerve blocks after ankle ORIF are associated with shorter hospital LOS, lower VAS, and reduced narcotic intake without increasing rates of ED visits, hospital readmissions, or complications.

Anatomical Variations of the Sciatic Nerve Exit from the Pelvis and Its Relationship with the Piriformis Muscle: A Cadaveric Study

BACKGROUND

The sciatic nerve (SN) is the widest nerve of the human body that exits the pelvis through the greater sciatic foramen, usually below the piriformis muscle (PM), and descends between the greater trochanter of the femur and ischial tuberosity of the pelvis to the knee. The aim of this paper is to examine and identify the SN variations in relation to the PM, its prevalence, pattern, and course.

METHODS

A prospective-descriptive cross-sectional study was carried out to determine the frequency of anatomical variations in the exit of the SN in relation with the PM in 20 anatomical bodies (corpses) of both genders, in equal numbers.

RESULTS

The dissection of 40 SNs in corpses of both sexes in equal numbers showed that the SN exited inferior to the PM in 37 lower limbs (92.5%); between the fascicles of the PM and inferior to the PM in two lower limbs (5%); and in one thigh, between the fascicles of the PM and superior to the PM (2.5%). Our study reported that the SN divides in its terminal branches more commonly in the proximal part of the popliteal fossa in 55% of cases, in the gluteal region in 35% of cases, and in the middle third of the thigh in 10% of cases.

CONCLUSIONS

Anatomical variations of the SN in relation to the PM are challenging for the diagnostic and therapeutic procedure in many clinical and surgical cases. Rapid recognition of the SN changes makes surgical approaches more accurate and effective. Our study confirmed that the SN exits the pelvis most commonly below the PM, although some anatomical variations may occur.

Intelligent Three-Dimensional Reconstruction Algorithm-Based Ultrasound-Guided Nerve Block in Intraoperative Anesthesia and Postoperative Analgesia of Orthopedic Surgery

This research was aimed at analyzing the role of ultrasound-guided nerve block based on intelligent three-dimensional (3D) reconstruction algorithm in intraoperative anesthesia and postoperative analgesia of orthopedic surgery. 68 elderly patients were undergoing orthopedic surgery on the lower extremities, and they were randomly rolled into two groups with 34 patients in each group. The patients in control group received sciatic nerve block anesthesia (SNBA), and the patients in the experimental group received ultrasound-guided SNBA (UG-SNBA) under 3D reconstruction algorithm to analyze and compare the anesthesia effect and the postoperative analgesia effect. The results showed that compared with other algorithms, the evaluation index of ultrasound images processed by the 3D reconstruction algorithm was better. In terms of anesthesia effect, there was no significant difference in systolic blood pressure, diastolic blood pressure, and heart rate between the two groups before surgery ( $P>0.05$ ). Intraoperative and postoperative indicators of the experimental group were significantly better than those of the control group; the drug dosage (61 mg) was less than that of the control group (78 mg). In addition, the onset time of anesthesia, the time of pain blockade, and the postoperative awake time (5 minutes, 8 minutes, and 8 minutes, respectively) were shorter than those in the control group (13 minutes, 15 minutes, and 15 minutes, respectively). The visual analogue scale (VAS) scores of the experimental group were better than those of the control group on the day after surgery, one day after surgery, two days after surgery, and three days after surgery, with significant differences ( $P<0.05$ ). In summary, 3D reconstruction algorithm-based ultrasound image effect was clearer, the effect of UG-SNBA was more stable, and the postoperative analgesic effect was better. This work provided a higher reference for the selection of safe and effective anesthesia options in orthopedic surgery.

Identification of the popliteal sciatic nerve through the above-knee lateral approach provides superior echogenicity and ultrasound visibility: a patient volunteer trial

BACKGROUND

Distinguishing light-echoed nerves from surrounding structures is challenging but may be important in nerve block administration. We evaluated the effect of patient characteristics on the echogenicity or visibility of the popliteal sciatic nerve (PSN).

METHODS

This study included adult patients who presented to the operating room as volunteers. The primary outcome was the success rate of nerve identification by ultrasound using different PSN access paths. The secondary outcome included the PSN visibility score (VIS), scan time, and PSN depth. Logistic regression analysis was used to identify factors associated with the PSN identification success rate. The body mass index (BMI) proximal-based cut-off was used to compare the PSN identification success rate through different access paths.

RESULTS

The PSN was successfully identified in 89.7% of the volunteers. The access paths (P < 0.01) and BMI (P = 0.01) were identified as independent predictors of successful PSN identification. A higher PSN identification success rate (P = 0.01), a higher VIS (P < 0.01), a more superficial PSN depth (P < 0.01), and a shorter scan time (P < 0.01) were observed in the above-knee lateral approach. Among volunteers with BMI ≥ 26.77 kg/m2, the PSN identification success rate through the above-knee lateral approach was significantly higher (P < 0.01), and PSN depth was shallower (P < 0.01) than through the medial approach.

CONCLUSIONS

The ultrasound-guided above-knee lateral approach for PSN block improved the PSN identification success rate, ensured a more superficial nerve location, and provided a clearer image.