Approach affects injectate spread in ultrasound-guided thoracic paravertebral block: a cadaveric trial

Effectiveness and safety of ultrasound-guided thoracic paravertebral block versus local anesthesia for percutaneous kyphoplasty in patients with osteoporotic compression fracture

BACKGROUND

Kyphoplasty for osteoporotic vertebral compression fractures (OVCF) is a short but painful intervention. Different anesthetic techniques have been proposed to control pain during kyphoplasty; however, all have limitations.

OBJECTIVE

To compare the effectiveness and safety of ultrasound-guided thoracic paravertebral block with local anesthesia for percutaneous kyphoplasty (PKP).

METHODS

In this prospective study, non-randomized patients with OVCF undergoing PKP received either ultrasound-guided thoracic paravertebral block (group P) or local anesthesia (group L). Perioperative pain, satisfaction with anesthesia, and complications were compared between the groups.

RESULTS

Mean intraoperative (T1-T4) perioperative visual analog scale (VAS) scores were significantly lower in group P than in group L (2 [1-3] vs. 3 [2-4], 2 [2-3] vs. 4 [2-4], 2 [2-3] vs. 5 [3-5], and 3 [2-3] vs. 5 [3-5], respectively; P< 0.05). Investigators' satisfaction scores, patients' anesthesia satisfaction scores, and anesthesia re-administration intention rate were significantly higher in group P than in group L (4 [3-5] vs. 3 [2-4], 2 [2-3] vs. 2 [1-3], 90.63% vs. 69.70%; P< 0.05). There was no significant intergroup difference in complications.

CONCLUSIONS

Ultrasound-guided thoracic paravertebral block has similar safety to and better effectiveness than local anesthesia in PKP.

The pathway of injectate spread during thoracic intertransverse process (ITP) block: Micro-computed tomography findings and anatomical evaluations

STUDY OBJECTIVE

To investigate the mechanism of action of the thoracic intertransverse process (ITP) block.

DESIGN

Three-dimensional micro-computed tomography (3D micro-CT) study and cadaveric evaluation.

SETTING

A translational research unit for anatomy and analgesia in a university hospital.

PATIENTS

Twelve embalmed and three non-embalmed human cadavers were used in this study.

MEASUREMENTS

Micro-CT images of the mid-thoracic paravertebral space and its adjacent ligamentous tissues were acquired and 3D images were reconstructed. Manual dissection and histologic examination of these structures complemented the images. To confirm our findings, the dye-spreading pattern after ultrasound-guided ITP injection of 20 mL dye solution at T4-T5 was evaluated.

MAIN RESULTS

Micro-CT and histologic findings showed that the costotransverse foramen (the medial slit of the superior costotransverse ligament) and the costotransverse space (between the rib and the transverse process) were potential pathways to the thoracic paravertebral space during ITP block. Single-level ITP injection with a dye solution resulted in a multilevel segmental paravertebral spread in cadaveric evaluation.

CONCLUSIONS

The space posterior to the superior costotransverse ligament, the target area for ITP blocks, has potential anatomical pathways to the thoracic paravertebral space. The costotransverse foramen and the costotransverse space provided the anatomical conduit for the anterior and intersegmental paravertebral spread of the ITP block.

Observation and measurement of applied anatomical features for thoracic intervertebral foramen puncture on computed tomography images

BACKGROUND

Thoracic intervertebral foramen puncture is the key step for interventional therapy on the thoracic nerve roots or dorsal root ganglia. The anatomical features of the thoracic spine are complex, and puncture injury to the pleura, blood vessels, spinal cord, and other tissues may cause serious complications. The spatial anatomical characteristics and related parameters for thoracic intervertebral foramen puncture remain poorly understood.

AIM

To observe and summarize the spatially applied anatomical characteristics for intervertebral foramen puncture on different vertebral segments.

METHODS

A total of 88 patients (41 males and 47 females) who underwent thoracic minimally invasive interventional treatment at Nanjing Drum Tower Hospital from January 2019 to June 2020 were included. Computed tomography images of 167 thoracic vertebral segments scanned in the prone position were collected. The width of the intertransverse space (D_P), the height of the rib neck/head above the lower transverse process (D_R), the width of the lateral border of the articular process/lamina (W_P), and the width of the posterior border of the vertebral body (W_V) were measured. At the upper 1/3 of the intervertebral foramina, the horizontal inclination angle (α) from the lateral border of the articular process/lamina to the posterolateral border of the vertebral body was measured. The ratios D_R/D_P and W_P/W_V were calculated. The intervertebral foramen parameters were compared between segments.

RESULTS

No rib head/neck occlusion (D_R/D_P > 0) was found in the intertransverse spaces of T1-2 and T12-L1. The incidence of occlusion for the upper thoracic segments (T1-5, n = 138), middle thoracic segments (T5-9, n = 116), and lower thoracic segments (T9-L1, n = 80) were 76.81%, 100%, and 82.50%, respectively. The incidence of occlusion for the middle thoracic segments was significantly higher than that for the upper and lower thoracic segments (P < 0.05). The incidence of > 1/2 occlusion (D_R/D_P > 1/2) for the upper, middle, and lower thoracic segments was 7.97%, 74.14%, and 32.50%, respectively. The incidence of > 1/2 occlusion for the middle thoracic segments was significantly higher than that for the upper and lower thoracic segments (P < 0.05). W_P was longer than W_V on T1-2 to T9-10 and shorter than W_V on T10-11 to T12-L1. The horizontal puncture angle (α) into the external opening of the intervertebral foramina was positively correlated with the segments of the thoracic vertebrae from the cephalic to caudal portion (left: r = 0.772, P < 0.01; right: r = 0.771, P < 0.01), and the horizontal inclination angle for T11-12 and T12-L1 was 90°.

CONCLUSION

It is necessary to identify the spatial impact of the rib head/neck on the puncture path of the intervertebral foramina and design appropriate puncture angles for different segments.

Ultrasound-Guided Thoracic Paravertebral Block as a Sympathetic Blockade for Upper Extremity Neuropathic Pain: A Prospective Pilot Study

Purpose

Ultrasound-guided thoracic paravertebral block (US-TPVB) is considered a treatment option for the management of acute pain in various pain-related conditions. We conducted a prospective pilot study to evaluate the possibility of US-TPVB as a sympathetic blockade in patients with neuropathic pain disorders in the upper extremities.

Patients and Methods

A total of 12 patients underwent US-TPVB between the T2 and T3 paravertebral space with 10 mL of 1% mepivacaine. The temperature change (°C) before and after the procedure was compared between the ipsilateral and contralateral hands. We counted the proportion of patients showing a temperature increase ≥1.5°C and compared a change in the pain intensity before and after the procedure.

Results

The median increase in the temperature change between the ipsilateral and contralateral hands was 1.54°C (interquartile range, 1.28–2.20). There were seven patients (58.3%) who showed a temperature difference ≥1.5°C between both hands after the US-TPVB. Eleven patients (91.7%) reported a reduction in pain according to the score on the 11-point numerical rating scale. No serious complications relevant to the procedure were reported.

Conclusion

US-TPVB could be a useful technique for sympathetic blockade in patients with upper extremity pain.

Distribution of injectate administered through a catheter inserted by three different approaches to ultrasound-guided thoracic paravertebral block: a prospective observational study

Background

Despite the popularity of continuous thoracic paravertebral block (TPVB), there is a paucity of information on catheter tip position and distribution of injectate through the catheter. We observed, in real time, the spread of dye, the catheter tip position and sensory block levels produced with three different (intercostal (IC), transverse process sagittal (TS) and paralaminar (PL)) approaches to ultrasound-guided TPVB in patients undergoing video-assisted thoracoscopic surgery.

Methods

After the induction of general anesthesia, ultrasound-guided TPVB was conducted with a patient in the lateral decubitus position. During surgery, 10 mL of dye was injected through a catheter to observe the catheter tip and the dye distribution under thoracoscopy. Dermatomal sensory block levels were measured postoperatively.

Results

Ten patients for each of three different approaches completed the study. There were a variety of dye spreading patterns. The median (range) number of segmental levels stained with dye was 1.5 (1–4), 3 (1–4) and 3 (1–5) with the IC, TS and PL approaches, respectively. We observed that a catheter tip was present at the same segmental paravertebral space as intended in 50%–90% of patients using these approaches. The median (range) number of dermatomes with sensory blockade at 6 hours after block was 2.5 (1–4), 3 (2–8) and 3 (1–8) with the IC, TS and PL approaches, respectively.

Conclusions

Although a bolus injection through a catheter for ultrasound-guided TPVB produced multiple levels of spread and sensory blockade in more than half the patients, considerable differences existed in the spread regardless of approach.

Programmed intermittent bolus infusion versus continuous infusion of 0.2% levobupivacaine after ultrasound-guided thoracic paravertebral block for video-assisted thoracoscopic surgery: A randomised controlled trial

BACKGROUND

The analgesic benefits of programmed intermittent bolus infusion for thoracic paravertebral block remain unknown.

OBJECTIVE

The aim of this study was to compare the analgesia from intermittent bolus infusion with that of a continuous infusion after thoracic paravertebral block.

DESIGN

A randomised controlled study.

SETTING

A single centre between December 2016 and November 2017. Seventy patients scheduled for video-assisted thoracoscopic surgery were included in the study.

INTERVENTION(S)

Patients were randomly assigned to receive 0.2% levobupivacaine via continuous infusion (5 ml h, continuous group) or programmed intermittent bolus infusion (15 ml every 3 h, bolus group) after an initial 15-ml bolus injection of 0.2% levobupivacaine.

MAIN OUTCOME MEASURES

The main outcome was the amount of rescue fentanyl (per kg of body weight) consumed within 24 h after surgery. Secondary outcomes were postoperative pain scores, plasma levobupivacaine concentrations and the number of dermatomes anaesthetised.

RESULTS

There was no significant difference between the continuous and bolus groups in the postoperative consumption of fentanyl (median [interquartile range] 5.5 [4 to 9.5] μg kg versus 6 [3.5 to 9] μg kg respectively, P = 0.45) and postoperative pain scores within 24 h. At 20 h after initiating the infusions, there was no statistically significant difference between the two groups in terms of the plasma levobupivacaine concentration. The number of dermatomes anaesthetised to pinprick and cold testing was significantly greater in the bolus group.

CONCLUSION

Our findings suggest that postoperative pain and opioid usage are similar with either programmed intermittent bolus infusion or continuous infusion after thoracic paravertebral block. Programmed intermittent bolus infusion provides a wider sensory blockade and could benefit patients requiring a wider extent of anaesthesia.

TRIAL REGISTRATION

UMIN Clinical Trials Registry (UMIN-CTR; URL: http://umin.ac.jp/ctr/, ID: UMIN000023378).

Thoracic paravertebral block: comparison of different approaches and techniques. A study on 27 human cadavers

BACKGROUND AND OBJECTIVES

The success rate and spread of thoracic paravertebral block (TPVB) are variable and difficult to predict. It is now recommended that an ultrasound guidance technique should replace the traditional landmark technique. The objective was to compare anatomical outcomes of both techniques on cadavers.

METHODS

A landmark technique (loss of resistance technique [LOR]) and a USG technique (three approaches: sagittal, transversal in-plane, transverse out-of-plane) were performed on 27 thawed non-embalmed cadavers. Each of the four approaches was performed in each body (T3-T5 and T9-T11 × right and left). A coloured solution (13 mL, saline 0.9%) was injected in the targeted thoracic paravertebral space (TPVS). A successful thoracic paravertebral injection (TPVI) was defined by the presence of dye in at least one TPVS during anatomical dissection.

RESULTS

In 104 TPVIs analysed, the overall success rate was 78%. Factors associated with success were: USG versus LOR technique (85% vs. 52%, P < 0.0007), sagittal versus both transversal approaches (93%/81%/83%, P < 0.0007) and right side (86% vs. 66%). The median spread was 2 TPVS (min - max 1-5) with a median cephalad-caudal spread of 5 cm (min - max 1-18). By multivariate analysis, the sagittal approach was an independent factor of success (OR 2.75). Dye spread and pleural entry were influenced by neither the approach nor the site of injection.

CONCLUSIONS

Paravertebral spread of TPVI is variable. USG technique has higher anatomical success rates than the LOR technique, the sagittal USG approach being the most successful.

Comparison of analgesic efficacy between two approaches of paravertebral block for thoracotomy: A randomised trial

BACKGROUND

Although several approaches for ultrasound-guided thoracic paravertebral block have been introduced, little is known regarding the differences in analgesic efficacy. We conducted this prospective randomised trial to examine whether the type of approach for ultrasound-guided thoracic paravertebral block could affect analgesic quality in thoracotomy.

METHODS

Patients scheduled for video-assisted thoracotomy were randomly allocated into two groups by block technique: the intercostal approach (group IC) or the paralaminar approach (group PL). At the start and end of surgery, 20 mL of 0.5% ropivacaine was injected, followed by a continuous infusion of 0.2% ropivacaine at 5 mL h^-1 . We also started intravenous fentanyl patient-controlled analgesia at 0.5 μg kg^-1  h^-1 and bolus dose of 15 μg. The main outcome was the number of rescue fentanyl use. We also evaluated postoperative pain scores and number of blocked dermatomes showing a reduced sensation.

RESULTS

Enrolment was ceased because of implementation of a minimally invasive surgical method. Overall, 42 subjects completed the trial for analysis. The number of rescue fentanyl use in group PL was significantly less than that in group IC at 3, 6, 12 and 24 hour postoperatively. The numerical rating scale (NRS) at rest in group PL was significantly lower at 1, 3, 6, and 12 hour postoperatively. Patients in Group PL developed significantly wider sensory block level (median (IQR [range]); 4 (4-5 [2-7])) than those in Group IC (3 (3-3 [2-9])).

CONCLUSIONS

We suggested that paralaminar approach provided superior analgesia for thoracotomy rather than the intercostal approach.