European Journal of Cardiovascular Medicine

Pain is more than a symptom—it is a complex sensory and emotional response involving intricate neural mechanisms. The International Association for the Study of Pain (IASP) defines it as “an unpleasant sensory and emotional experience associated with or resembling actual or potential tissue damage”[1]. Beyond patient discomfort, poorly managed postoperative pain can impair healing, increase hospital stays, and contribute to psychological distress[2].

Regional anaesthesia techniques have gained traction due to their ability to minimize systemic drug use and enhance functional recovery[3]. Among these, the paravertebral block and peri-tubal infiltration are promising strategies for pain management in patients undergoing percutaneous nephrolithotomy (PCNL).

PCNL is a minimally invasive surgical technique for removing large or complex kidney stones. Despite its effectiveness, it often results in significant postoperative pain due to the trauma involved, particularly at the flank and renal parenchymal sites[4].

This pain is both somatic, from the incision and paracostal muscle injury, and visceral, from the renal capsule stretch and inflammation(5). While paravertebral block acts at the spinal level to block nociceptive transmission, peri-tubal infiltration works at the site of injury, providing localized relief(6).

Study Design

This was a prospective, randomized, controlled clinical study conducted at Department of Anaesthesiology, Super speciality block Shyam Shah Medical College Rewa (M.P.)  to evaluate and compare the efficacy of paravertebral block (PVB) and peri-tubal infiltration (PTI) in managing postoperative pain following percutaneous nephrolithotomy (PCNL).

Participants

A total of 90 patients aged between 18-60 years, undergoing PCNL for renal stones, were enrolled. Patients with coagulopathy, allergy to local anaesthetics and spinal deformities were excluded.

Randomization and Groups

Participants were randomized into three groups:

• Group B: Received a paravertebral block with Inj. Levobupivacaine 0.25% 15ml at the T11, T12 and L1 level.
• Group I: Received peri-tubal infiltration of Inj. Levobupivacaine 0.25% 20ml around the nephrostomy tube tract.
• Group C: Received standard analgesic regimen. Standard analgesic regimen comprised of IV paracetamol 1 gm and inj. diclofenac 75 mg IM intraoperatively.

Procedure

All patients underwent PCNL under standardized general anaesthesia. After the surgical procedure, the designated pain management intervention was administered according to group allocation.

Paravertebral Block (Group PVB)- After completion of the surgical procedure and prior to patient emergence from anaesthesia, a unilateral thoracic paravertebral block was performed under ultrasound guidance. The patient was positioned laterally, with the operative side facing up.

• A high-frequency linear probe was used to identify the transverse process at the T10–T12 level, depending on the side and location of the nephrostomy tract.
• After skin disinfection and local infiltration with lidocaine, a 22G spinal needle was advanced using an in-plane technique until the tip was positioned in the paravertebral space.
• Following negative aspiration, 15 mL of 0.25% Levobupivacaine was injected incrementally, with real-time visualization of the spread of local anaesthetic.

Peri-tubal Infiltration (Group PTI) - At the end of the PCNL procedure and after nephrostomy tube placement, local anaesthetic infiltration was performed under direct vision. A 20 mL of 0.25% Levobupivacaine was infiltrated into the tissue layers surrounding the nephrostomy tract.

Anaesthetic technique:

A detailed history of all selected patients was taken. A thorough pre-anaesthetic evaluation including the airway, back of the patient and site of block assessment was performed. The patients were explained about the entire procedure, informed consent was taken from them. They were also educated about the Numerical Rating Scale (NRS).

After shifting the patient to operation theatre all routine monitors including ECG, pulse oximeter, and non-invasive B.P. cuff was attached and an 18/20 G intravenous catheter was secured for administering intravenous fluid and drugs. Vital parameters HR, SBP, DBP, MAP and oxygen saturation (SpO₂) was recorded.

After pre-oxygenation with 100% O₂ for 3 min, anaesthesia was induced with a standard anaesthetic protocol using fentanyl 2mcg/kg, Propofol 1.5-3mg/kg and tracheal intubation with appropriate sized cuffed endotracheal tube was facilitated by Atracurium 0.5 mg/kg intravenously.

Lungs were mechanically ventilated and anaesthesia was maintained using nitrous oxide, oxygen (FiO2 0.40) with sevoflurane (MAC 1.0 -1.2) and Atracurium 0.1 mg/kg. After the insertion of a ureteric catheter, the patients were placed in the prone position.At the end of surgery under strict aseptic precautions, a paravertebral block was performed under ultrasound guidance at the T11, T12 and L1 levels using 0.25% Levobupivacaine at a total dose of 15 mL in Group B. The paravertebral space in the ultrasound view is defined as the area between the costotransverse ligament, pleura, and transverse process. A 22-gauge insulated echogenic needle was advanced in the vertical-to-caudal direction using the in-plane technique. After the needle enters the paravertebral space, 5 mL of 0.25% Levobupivacaine was injected in each dermatome level, following negative aspiration for blood. The spread of the local anaesthetic was confirmed by anterior movement of the pleura in the paravertebral space.

In group I, under strict aseptic precaution a 23 G spinal needle was passed along the nephrostomy tube (22-24Fr) under fluoroscopic guidance. The needle was inserted about 1cm from nephrostomy tube in 6’O clock and 12’O clock position and the drug was injected from renal capsule upto the skin.

At each position about 10ml of 0.25% Levobupivacaine was injected, along the renal capsule, muscle, subcutaneous tissue and skin that makes up 20ml totally.

The Group C received standard analgesic regimen consisting IV Paracetamol 1 gm intraoperatively along with Inj. Diclofenac 75 mg IM intraoperatively.

After performing the procedure, the patients were turned to supine position and once the respiratory attempts were adequate, patients were extubated following administration of Inj Neostigmine 2.5mg and Inj. Glycopyrrolate 0.5 mg. Then the post operative parameters were recorded and the patient was patient was shifted to PACU (Postanesthesia care unit). Postoperative pain was assessed using Numerical Rating Score (NRS).

The following parameters were monitored

1. Vital signs- Heart rate, SBP, DBP, MAP.
2. NRS (Numerical Rating Score)
3. Mean time of demand for rescue analgesia.
4. Total requirement of rescue analgesia in 24 hours.

Adverse events – Nausea, vomiting, rigor, hypothermia, hemodynamic instability

Numerical Rating Score

The scale consists of 10cm line anchored at one end by a label “no pain” and at the other end by a label “the worst pain imaginable” or “pain as bad as can be”. The patient simply marks the line to indicate pain intensity and a slide-rule like device with the line on patient’s side.

       1-2= no pain

       3-4= mild pain,

       5-6= moderate pain,

       7-8= severe pain,

       9-10= intolerable pain

NRS pain score was recorded at 0, 2, 4, 8, 12 and 24 h after the completion of surgery. Effective analgesia was defined as NRS score between 0 to 4. When NRS score was more than 4 rescue analgesia was given that time was noted as time of demand of rescue analgesia. Inj. Tramadol 100 mg IV was given as rescue analgesic. At the end of 24 h, total tramadol consumption was noted.   Patient was also monitored for local anesthetic toxicity during postoperative period.

Figure: Study flowchart

1. Patient Demographics and Baseline Characteristics

 No statistically significant differences were observed between the groups in demographic or surgical parameters.

2. Postoperative Pain Scores (NRS)

Differences between Group B and Group I were statistically significant from 4 hours onwards, indicating that while both analgesic techniques were effective, the paravertebral block (Group B) provided more effective and sustained pain relief than peritubal infiltration (Group I) and Control (Group C).

3. 3. Mean time of demand for rescue analgesia

Patients in the Group B required rescue analgesia significantly later than those in the Group I and Group C.

Ultrasound-guided paravertebral block (PVB) and peritubal infiltration of levobupivacaine represent two distinct techniques for providing postoperative analgesia following percutaneous nephrolithotomy (PCNL). The PVB is a more comprehensive regional anaesthesia method, offering superior pain relief by targeting multiple nerve roots, providing analgesia for both somatic and visceral pain. This technique reduces the need for systemic opioids, resulting in fewer opioid-related side effects, such as nausea, vomiting, and respiratory depression, which leads to enhanced patient satisfaction due to longer-lasting and more effective pain control. While it requires specialized equipment and expertise, ultrasound guidance significantly reduces the risks of complications like pleural puncture and nerve injury, making it a favourable option in center equipped with the necessary resources.

On the other hand, peritubal infiltration of levobupivacaine is a simpler and less invasive technique, often performed with fewer complications and reduced costs. It provides localized analgesia around the nephrostomy tube or surgical site, but its effects are generally more short-lived and limited to somatic pain. While it can be effective for early postoperative pain relief, the infiltration technique may lead to increased opioid consumption as the anaesthetic effect wanes more quickly, potentially resulting in higher overall pain scores and slower recovery times. Despite being easier to perform, particularly in resource-limited settings, the peri tubal infiltration technique may not offer the same level of comprehensive pain management as the ultrasound-guided PVB, making it less ideal for longer, more invasive procedures like PCNL.

In the present study age distribution across the three groups—Group B (Paravertebral Block), Group I (Peritubal Infiltration), and Group C (Control)—shows some differences. Group B has a mean age of 36.8±14.447 years, Group I have 36.33±14.596 years, and Group C has 40.7±12.946 years. Statistical analysis reveals a significant p-value between Group C and the other two groups (p = 0.0121 for Group C vs. Group B and Group I), indicating that age differences may be more pronounced in the control group. Although the p-values for Group B (p = 0.0850) and Group I (p = 0.0307) suggest some age-related variation, the difference between these two groups and the control group is more significant, with Group C being relatively older.

Karthik G.S. et al⁷, (2024) they found 35.6±6.1 years of mean age in group Erector spinae plane block and 36.1±7.2 years of mean age in group Paravertebral block with 0.7 p value.

In another study done by K. Shankar et al⁸ (2022) they had three groups in which Group Paravertebral block had 39.85 years of mean age, Group Peri tubal infiltration had 40.05 years of mean age and control group, Group C had 39.60 years of mean age respectively.

In our study the ASA (American Society of Anaesthesiologists) grading across the three groups showed a fairly similar distribution of physical status. In Group B (Paravertebral Block), 20 participants were classified as ASA I and 10 as ASA II. Group I (Peri tubal Infiltration) had 22 ASA I and 8 ASA II patients, while Group C (Control) had 15 ASA I and 15 ASA II participants. This indicates that most participants across all groups were ASA I, with a smaller proportion classified as having mild systemic disease (ASA II). The distribution of ASA grades appears balanced between the groups, minimizing the potential for physical status to bias the results.

In a study done by Karthik G.S. et al⁷, (2024) they found in ASA grade I 13 (52%) patients were in Group Erector spinae plane block and 12 (48%) patients in group Paravertebral block as well as in ASA grade II 12 (48%) patients were in Group ESPB and 13 (52%) patients were fall in the category of Group Paravertebral block respectively.

In our study the numerical rating scale (NRS) for pain assessment across the three groups (Group B, Group I, and Group C) reveals significant differences in pain scores over time, particularly between the two treatment groups (Paravertebral Block and Peritubal Infiltration) compared to the control group. Immediately after the surgery, the pain scores were similar across all groups, with no significant differences. However, from 2 hours post-surgery onward, Group C (Control) showed significantly higher pain scores compared to both Group B (Paravertebral Block) and Group I (Peritubal Infiltration), with p-values consistently below 0.0001. By 24 hours, Group C continued to experience the highest pain scores (5.0 ± 0.7878), while Group B and Group I had lower scores (3.46 ± 0.8604 and 4.25 ± 0.6816, respectively). This highlights the superior effectiveness of the paravertebral block and peritubal infiltration techniques in providing sustained postoperative analgesia compared to the control group.

Koch et al⁹., (2018) in their study reported that pain intensity decreased dramatically in the initial hours and was significantly lower in the paravertebral block group compared to the control, particularly 2 hours post-surgery onward, which correlates with our findings of lower pain scores for Group B at the 2-hour and 24-hour marks.

A study by Zhao et al¹⁰. (2016) on abdominal surgeries found that peritubal infiltration using local anesthetics significantly reduced pain scores compared to controls. The results from their study were similar to ours in that peritubal infiltration provided sustained pain relief, with statistically significant differences observed from 2 hours post-surgery and continuing through 24 hours. They reported that the peritubal infiltration group had reduced pain scores, with results aligning with our Group peri tubal infiltration findings of lower pain scores compared to the control group.

In present study the total requirement for rescue analgesia across the three groups shows significant differences in analgesic consumption, with Group B (Paravertebral Block) requiring the least amount of additional analgesia. Group B had the highest number of participants (11) who required no rescue analgesia, compared to only 1 in Group I (Peritubal Infiltration) and none in Group C (Control). Moreover, Group C had the highest requirement for higher doses (150mg and above), with 11 participants needing 150 mg of rescue analgesia. The Chi-square test result of 46.717 with a p-value of <0.0001 indicates a statistically significant difference in the analgesic needs among the groups, emphasizing that the paravertebral block provided the most effective pain relief, reducing the need for additional analgesia compared to peritubal infiltration and the control group.

In our study the mean dose of rescue analgesic (Tramadol) required was significantly lower in Group B (Paravertebral Block), with a mean of 55±56.248 mg compared to Group I (Peritubal Infiltration) at 100±54.772 mg and Group C (Control) at 129.31±60.529 mg. The p-values of 0.0012 (B vs. I), <0.0001 (B vs. C), and 0.0270 (I vs. C) indicate statistically significant differences, with Group B requiring the least amount of rescue analgesia.

In a study done by Prashant Lomate et al¹¹, (2022) they found number of rescue analgesics requires and total consumption of tramadol in 24 hours were less in Group Erector spinae block than in Group peri tubal infiltration.

In study done by Yayik et al¹² (2021) while analyzing the total number of rescue analgesia needed in 24 hrs postoperatively following PCNL surgeries, paravertebral group had a mean value of 2.90 ± 0.84 and peritubal group had 4.47± 0.73. This showed that the need for rescue analgesia was more in peritubal group.

These findings were consistent with that of Geetha et al¹³ (2020) where the mean number of analgesic demands after peritubal infiltration during first 24 hrs was 2.39± 1.03 and that of Lojanapiwat et al¹⁴ (2015) which concluded that paravertebral block showed a reduction in total opioid consumption when compared with the control group.

Limitations of the study

1. Study was conducted on relatively small sample size which limit the clinical and statistical valid observation.
2. The study was conducted in single centre therefore affected by institutional practice and patient demographics.
3. Short term follow-up hence focused on acute post operative pain.
4. Postoperative pain is a subjective experience and can be difficult to quantify objectively.
5. Exclusion criteria – patient with comorbidities were excluded hence, limiting the applicability of the result to comorbid populations.
6. The major limitation is dermatomal limitation of block. We did not assess block success by evaluation of dermatomal sensory loss.

We conclude that both peritubal infiltration and paravertebral block are effective regional analgesia techniques for managing postoperative pain in percutaneous nephrolithotomy surgery. Peritubal infiltration is easy to administer and provides significant pain relief till 4 hours postoperatively. However, the paravertebral block offers superior and more prolonged analgesic benefits in the later postoperative period as evidenced by prolonged duration of analgesia, lower pain scores in first eight hours and reduced total analgesic consumption in 24 hours postoperatively.

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