|Year : 2017 | Volume
| Issue : 3 | Page : 180-185
Comparison between single-level and multi-level unilateral thoracic paravertebral block in patients undergoing modified radical mastectomy
Sanjay Kalani, C V Prashanth Kumar, Suresh Chandra Dulara
Department of Anesthesiology, Government Medical College and Associated Hospitals, Kota, Rajasthan, India
|Date of Web Publication||18-Jan-2018|
198-B, Indira Vihar, Kota - 324 005, Rajasthan
Source of Support: None, Conflict of Interest: None
Background: General anesthesia (GA) is the conventional norm whenever major breast surgeries are thought of. However, in recent years, thoracic paravertebral block (TPVB) has emerged as a potential alternative to GA. Previously, studies have compared analgesic efficacy between TPVB administered before GA and GA alone. Aims and Objectives: we aimed to compare analgesic efficacy and safety between multi-level TPVB (MPVB) and single-level TPVB (SPVB) in modified radical mastectomy (MRM). Main objective was to assess the duration of postoperative analgesia provided by MPVB and SPVB. Materials and Methods: In this prospective, randomized, double-blind study, we compared MPVB (Group M) with SPVB (Group S) using 0.3 ml/kg of 0.5% bupivacaine with 0.5 μg/kg dexmedetomidine in 60 American Society of Anesthesiologists I and II female patients who were posted for MRM. Patients were randomly allotted into Group M (n = 30) or S (n = 30). Results: Mean time to primary rescue analgesia (RA) administration was significantly longer in Group M than Group S (736.90 min vs. 581.57 min, P < 0.001). Frequency of primary RA (Group M 1.17 vs. Group S 1.87, P < 0.001) and primary RA consumption (Group M 101.17 mg vs. Group S 166.20 mg, P < 0.001) in the first 24 h of the postoperative period was significantly less in Group M than Group S. Postoperative nausea and vomiting occurred in 3.34% (n = 1) and 6.67% (n = 2) of Group M and Group S, respectively. Conclusion: Multi-level technique of administering TPVB is a better choice for providing stand-alone intraoperative anesthesia and postoperative analgesia in patients undergoing MRM.
|How to cite this article:|
Kalani S, Kumar C V, Dulara SC. Comparison between single-level and multi-level unilateral thoracic paravertebral block in patients undergoing modified radical mastectomy. Indian J Pain 2017;31:180-5
|How to cite this URL:|
Kalani S, Kumar C V, Dulara SC. Comparison between single-level and multi-level unilateral thoracic paravertebral block in patients undergoing modified radical mastectomy. Indian J Pain [serial online] 2017 [cited 2019 Jun 24];31:180-5. Available from: http://www.indianjpain.org/text.asp?2017/31/3/180/223670
| Introduction|| |
Major breast surgeries (i.e., simple mastectomy, modified radical mastectomy [MRM] with or without axillary lymph node dissection, and breast conservative surgeries) are commonly done under general anesthesia (GA). Apart from postoperative nausea and vomiting (PONV), sore throat, and postoperative pulmonary complications seen in patients undergoing GA, inadequately managed acute postoperative pain is also a well-established independent clinical risk factor for the development of persistent chronic postoperative pain. The incidence of which is as high as 50% of the women after breast surgery. Inadequately managed acute postoperative pain also increases the surgical stress response, postanesthesia care unit (PACU) stay, duration of hospitalization, and delays ambulation postsurgery.
Regional anesthesia techniques overcome or reduce the incidence of the above-mentioned complications and are gaining popularity of late over GA due to their ability to provide adequate surgical anesthesia as well as postoperative analgesia. Of the various regional anesthesia techniques, unilateral thoracic paravertebral block (TPVB) with monitored anesthesia care (MAC) sedation has been a popular choice for major, unilateral breast surgeries due to a plethora of advantages, namely, simple and easy to perform, maintains hemodynamic stability, abolishes surgical stress response and lower rate of complications, reduces analgesic consumption, preserves bladder sensation and lower limb motor power, and promotes early mobilization.,,, A meta-analysis done by Schnabel et al. concluded that PVB alone or in addition to GA provides a better postoperative pain control with little adverse effects when compared with other analgesic treatment strategies during breast surgeries. Likewise, other studies ,,,, have concluded in a similar manner.
TPVB refers to the technique of injecting local anesthetic drugs in thoracic paravertebral space (TPVS) wherein the spinal nerves emerge from the intervertebral foramina, thereby resulting in ipsilateral somatic and sympathetic blockade involving multiple contiguous dermatomes above and below the site of injection. Several different techniques are available for administering a TPVB. However, classical technique (involves eliciting loss of resistance) is commonly used. This classical technique can be administered by single injection, multiple injections, or continuous catheter infusion.,,, Further, visualization of the TPVS can be aided by ultrasound or localization of spinal nerve by nerve stimulator. In recent past, there have been studies on paravertebral block, but most of them compare the efficacy with GA or as an adjuvant to GA.,, There have been very few studies , comparing the efficacy of single-level versus multi-level paravertebral block for surgical anesthesia and postoperative analgesia. Hence, in our study, we compared unilateral single-level TPVB (SPVB) versus unilateral multi-level TPVB (MPVB) for both surgical anesthesia and postoperative analgesia in patients who were posted for elective, unilateral MRM.
| Materials and Methods|| |
After obtaining approval from the Institutional Ethics Committee, 60 female patients aged 18-65 years with the American Society of Anesthesiologists' physical status (ASA) I and II, posted for unilateral MRM, were enrolled in this prospective, randomized, double-blind study (separate resident anesthesiologists were assigned for block administration, intraoperative pain and hemodynamic monitoring, and for postoperative pain assessment) conducted at our tertiary care public hospital. Exclusion criteria included patient refusal, ASA III and above, failed block (absence of adequate sensory block in T2–T6 dermatomes), pregnant or lactating women, thoracic spine deformities, previous surgeries involving the thoracic spine, active dermatological infection(s) in desired dermatomes, psychiatric disorders, bleeding diathesis, chronic analgesic abuse, and drug allergies. Patients were randomly allotted to either of the two groups based on computer-generated random number table.
- Group S (n = 30) – Single-level, unilateral TPVB (SPVB) at the level of T4 vertebral level, administering 0.3 ml/kg of 0.5% bupivacaine with 0.5 μg/kg of dexmedetomidine
- Group M (n = 30) – Multi-level, unilateral TPVB (MPVB) from T2–T6 vertebral level, administering equally divided volume of 0.3 ml/kg of 0.5% bupivacaine with 0.5 μg/kg of dexmedetomidine at each level.
During preanesthetic consultation (PAC), a thorough evaluation of each patient was done as per institutional protocol. The patient was explained regarding TPVB and visual analog scale (VAS) for assessment of pain, both at rest and on movement. Written informed consent was obtained. NPO ≥6 h was advised. Tablet alprazolam 0.5 mg was given night before surgery.
On the day of the surgery, patients were taken to operation theater (OT) 30 min before the schedule. Baseline parameters such as heart rate (HR), electrocardiography, noninvasive blood pressure, oxygen saturation (SpO2), and respiratory rate were noted. Peripheral intravenous (IV) access with 18/20-gauge cannula secured and Ringers' lactate 500 mL infusion started. Premedication IV midazolam 0.04 mg/kg was given and IV fentanyl 2 μg/kg infusion over 15 min as a preemptive analgesic for TPVB. In sitting position, relevant anatomical landmarks were identified, and needle entry site was marked 2.5 cm lateral to the upper border of the spinous processes of either T4 or T2-T6. Universal aseptic precautions were followed before local anesthetic infiltration at the needle insertion site. A 22G Quincke spinal needle was introduced perpendicular to the skin until the needle encountered transverse process at a depth of around 4 cm, and then, the needle was withdrawn slightly and redirected caudally 1.0–1.5 cm until a pop or loss of resistance was felt (classic technique). After negative aspiration for air, blood, or cerebrospinal fluid, local anesthetic of the desired volume is injected depending on the group to which the patient belongs. After completion of the procedure, the patient was made to lie down, and the onset of loss of sensation to pinprick was assessed at regular intervals until 30-min postcompletion of the procedure, after which the procedure was considered a failure and switched over to GA. Irrespective of the group to which the patient was assigned, MAC sedation by propofol infusion was started giving a bolus dose of 0.5 mg/kg IV followed by infusion at 25-75 μg/kg/min. IV fentanyl 25 μg intermittent bolus was given if the heart rate or mean arterial pressure (MAP) increased >20% of baseline values. No PONV prophylaxis was given. The following parameters were noted.
- Procedure-performance time = time taken from ( first) needle insertion to injecting the local anesthetic (at final level) in TPVS
- The onset of sensory block = time between ( first) injection of a drug to the absence of response to pinprick discrimination at T4 level
- Intraoperative fentanyl 25 μg bolus requirements
- Total dose of propofol (in mg)
- Intraoperative parameters: HR, SpO2, MAP, respiratory rate (RR), and any complications (pleural puncture with or without pneumothorax, vascular puncture, inadvertent epidural or subarachnoid injection, and/or Horner's syndrome) were observed during intraoperative and first 24 h of postoperative period
- Duration of surgery = time from surgical incision to application of the last suture
- Surgeon satisfaction score using the Numeric Rating Scale (NRS 0–100, 0 = least satisfied to 100 = most satisfied).
After completion of surgery, the patient was transferred to PACU for close monitoring of postoperative pain, sedation as assessed by observers' assessment of awareness/sedation, PONV, and any other complications. Postoperative pain was assessed by VAS (0 cm = no pain and 10 cm = worst imaginable pain), both at rest (VAS-R) and on movement (VAS-M) of ipsilateral arm. VAS for postoperative pain was assessed at 0 min, 15 min, 30 min, 45 min, 1 h, 2 h, 4 h, 6 h, 12 h, 18 h, and 24 h of the postoperative period. VAS of ≥4 or analgesic request by the patient would require administration of primary rescue analgesia (RA), aqueous injection diclofenac sodium 1.5 mg/kg slow IV infusion. Duration of postoperative analgesia (time between last suture application and administration of RA in the postoperative period) was also noted. If VAS was ≥4 after 30 min of primary RA dose then secondary RA, injection tramadol 1–2 mg/kg IV was given. The occurrence of complications was documented and treated accordingly, i.e., PONV patients were treated with injection ondansetron 4 mg slow IV, accidental pleural puncture were observed for symptoms/signs of pneumothorax, and those with massive pneumothorax, tube thoracostomy was done. At the time PACU discharge, patient satisfaction score (NRS 0–100, 0 = least satisfied to 100 = most satisfied) for technique and postoperative analgesia was noted.
The primary outcome of our study was duration of postoperative analgesia, and secondary outcomes included total dose and frequency of RA in the first 24 h postoperative period, intraoperative requirements of fentanyl, PONV occurrence, intraoperative/postoperative complications, and patient satisfaction scores for the technique and postoperative analgesia.
| Results|| |
A minimum of 28 patients were required in each group considering 30% difference in the duration of postoperative analgesia between the 2 groups with a power of 90% and confidence interval of 95%, with Type 1 error of 0.05 and Type 2 error of 0.1. However, thirty patients were enrolled in each group considering dropouts or failure of block. Data were analyzed using the Statistical Package for the Social Sciences (version 21, SPSS Inc., Chicago, IL, USA). Statistical significance testing of categorical and noncategorical variables was done by Chi-square test and independent sample t-test, respectively. P < 0.05 was considered statistically significant.
Demographic data and preoperative and intraoperative parameters were comparable in both the groups with a nonsignificant reduction in intraoperative HR and MAP when compared to preoperative values (P > 0.05) [Table 1] and [Table 2]. The mean procedure-performance time in Group M was 17.82 min, and in the Group S, it was 6.92 min (P < 0.001). Mean onset of sensory block in Group M was 9.45 min, and in the Group S, it was 14.85 min (P < 0.001) [Table 3]. Duration of surgery and surgeon satisfaction scores was comparable in both the groups with no statistical significance between two groups [Figure 1]. Additional IV fentanyl 25 μg bolus, intraoperatively, was required in 1 (3.34%) and 3 (10%) cases in Group M and S, respectively.
Mean duration of postoperative analgesia was significantly higher in Group M than Group S (736.90 min v/s 581.57 min, P < 0.001). The mean primary RA, injection diclofenac sodium, dose in the first 24 h of the postoperative period was 101.17 mg in Group M and 166.20 mg in Group S, respectively (P < 0.001). The frequency of primary RA dose in the first 24 h of the postoperative period was 1.17 and 1.87 in Group M and S, respectively (P < 0.001) [Table 4] and [Figure 2]. None of the patients required secondary RA. Mean VAS scores at rest and movement, at the different postoperative time periods, were comparable with no statistical significance [Figure 3] and [Figure 4].
Incidence of PONV in Group S was 3.34% (n = 1) and in Group M was 6.67% (n = 2). We observed a single case of accidental pleural puncture without clinically significant pneumothorax in Group M. Neither sedation nor other complications were observed in the first 24 h of postoperative period.
| Discussion|| |
In the present study, the results convey that MPVB, as compared to SPVB, has superior postoperative analgesic efficacy as determined in terms of time to primary RA administration, total primary RA consumption, and frequency of primary RA given in the first 24 h of the postoperative period. Our findings are in sync with the work of R Kasimahanti et al., who evaluated the effect of single-level (Group S) versus double-level (Group D) TPVB found significantly lower RA consumption (diclofenac, Group D 115.7 mg vs. Group S 175.3 mg), significantly lesser frequency of RA administration (Group D 1.28 vs. Group S 1.78), and lesser postoperative analgesia duration (Group D 611 min vs. Group S 533 min) in double-level TPVB than single-level TPVB patients. This superiority in postoperative analgesic efficacy for MPVB is due to the predictable spread of the injectate in paravertebral space and thereby producing a predictable block. However, SPVB employs the process of injecting the entire volume at a particular level (T4 level in our study) and thereby relies on volume and speed of injection, position of the patient while TPVB administration, and position of the needle tip in the paravertebral space per se,, in dermatome spread and thereby leads to unpredictable block and probably inferior analgesic characteristics when compared to MPVB. Similarly, Uppal et al. compared between them and found that duration of analgesia was prolonged in multiple-injection TPVB, but this was statistically insignificant. They also noted that single-injection TPVB has equivalent dermatomal spread and takes less time to perform compared with a multiple-injection PVB, hence may be preferred over multiple-injection technique.
The superiority of MPVB comes at the cost of decreased patient satisfaction scores for the technique as SPVB patients are more satisfied with technique than MPVB. However, patients are more satisfied with postoperative analgesia provided by MPVB as seen from patient satisfaction scores for postoperative analgesia. The inference drawn is in accordance with studies which have singularly studied MPVB/SPVB and patient satisfaction scores for technique, analgesia, or overall satisfaction but not together.,
The procedure-performance time for MPVB is significantly longer and the onset of sensory block significantly shorter as compared to SPVB. This also means that the induction time (procedure-performance time + onset of the sensory block) for MPVB was observed to be longer than SPVB. The prolonged procedure-performance time for MPVB is obvious as multiple injections, which consume time, are administered to get the desired outcome. The shorter duration of onset for MPVB suggests the drug starts to act as soon as it is injected at a particular level in TPVS. We did not find studies that have compared induction time between MPVB and SPVB. However, studies have compared induction time by comparing SPVB/MPVB with GA, and in general, TPVB has prolonged induction time.,
In our study, 29 (96.67%) patients in Group M and 27 (90%) patients in Group S completed the surgery with TPVB and MAC sedation demonstrating that multi-level TPVB had a lesser chance of unpredictable spread of the injectate than single-level TPVB as observed in our study. Rest required IV fentanyl 25 μg boluses during the intraoperative period. No cases of failed block were observed in our study. Overall failed block rates in other studies were observed to be 0% in USG-guided  and 6.1%, 10.7% in non-USG-guided , technique, respectively.
PONV occurred in a total of 3 (5%) cases with 1 (3.34%) in MPVB and 2 (6.67%) in SPVB which was insignificant and comparable between the 2 groups. This is in line with clinical studies showing that PONV is not a significant complication postsurgery after TPVB ,,,,,, that would warrant combination prophylactic treatment in the intraoperative period. Accidental pleural puncture without clinically significant pneumothorax was observed in a single patient in MPVB group suggesting increased risk for procedure-related complications due to the sheer increase in the number of injections. Many other studies also observed this complication to be rare with accidental pleural puncture 0.8%, 1.1%, and pneumothorax 0.5%, and concluding it to be a safe technique. Neither sedation nor other complications were observed in the postoperative period.
There were a few limitations in our study. First, there was no control group of patients who received GA and postoperative pain managed by analgesics alone. Second, we did not observe the effect of adequately managed acute postoperative pain on the incidence of chronic postoperative pain.
| Conclusion|| |
The multi-level technique of administering TPVB is a better choice for providing stand-alone intraoperative anesthesia and postoperative analgesia in patients undergoing MRM. Despite the comparatively lower patient satisfaction score for the technique itself and marginally increased OT duration before surgical incision, the predictable spread of block and better acute postoperative pain control makes it a better choice than SPVB.
We would like to acknowledge the active support of the faculty members and residents of the Department of Anesthesiology, Government Medical College and Associated Hospitals, Kota (Rajasthan), India.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]
[Table 1], [Table 2], [Table 3], [Table 4]