Abstract
Objectives
The aim of this study was to examine the association between programmed intermittent paravertebral bolus infusion and chronic post-surgical pain (CPSP), including pain components and pain distribution, following video-assisted thoracoscopic surgery (VATS) in elderly patients.
Design
An Observational Study.
Setting
This study was conducted at Beijing Chest Hospital, Capital Medical University.
Participants
Elderly patients undergoing VATS.
Interventions
Patients in the paravertebral group received programmed intermittent paravertebral bolus infusion with local anesthetics postoperatively, while patients in the intravenous group received patient controlled intravenous analgesia (PCIA) with sufentanil.
Measurements and main results
CPSP in our study was defined according to the International Classification of Diseases (ICD-11). Among the 242 elderly patients, Group P had a lower incidence of persistent pain at 3 months postoperatively compared to Group I (3.5% versus 13.4%, p = 0.014). Group P also had a lower incidence of anterior chest pain than Group I at both 1 month (p = 0.005) and 3 months (p = 0.020) postoperatively. Additionally, at 3 months, Group P had a lower incidence of neuropathic pain than the Group I (p = 0.021). Furthermore, Group P demonstrated reduced rates of pricking pain and hyperesthesia compared to Group I (p = 0.024; p = 0.042).
Conclusions
Programmed intermittent paravertebral bolus infusion reduces the incidence of postoperative chronic pain in patients undergoing thoracic surgery. It also decreases the occurrence of neuropathic pain three months after surgery.
Keywords: Paravertebral analgesia, Postoperative chronic pain, Neuropathic pain, Thoracoscopic surgery, Elderly
Introduction
Video-assisted thoracoscopic surgery (VATS), a minimally invasive alternative to thoracotomy, has gained prominence due to its advantages in reducing surgical trauma and accelerating recovery. Despite its benefits in lessening acute pain severity, VATS still carries a high risk of acute postoperative pain (Kwon et al. 2017). If inadequately managed, postoperative acute pain may transition into chronic post-surgical pain (CPSP), which affects 20–40% of patients and significantly impairs quality of life (Fiorelli et al. 2020; Shanthanna et al. 2016). CPSP is defined as pain that is primary or increasing in intensity in the surgical area after a surgical procedure, persists beyond the normal healing period, and is not explained by another cause. Notably, neuropathic pain is often characterized by burning or electric shock-like sensations. It accounts for up to 30% of CPSP cases and is associated with greater pain severity and a broader anatomical distribution (Treede et al. 2015; Warfield et al. 2020).
While paravertebral blockade (PVB) has demonstrated efficacy in mitigating acute pain and reducing opioid consumption comparable to epidural analgesia (Kozar et al. 2011), its long-term benefits on CPSP components remain underexplored, particularly in elderly populations (Ma et al. 2021; Qian et al. 2019; Zhao et al. 2024). Recent trials have mainly evaluated CPSP as a dichotomous outcome and often as a secondary endpoint, with limited power to detect nuanced differences between analgesic strategies (Elsharkawy et al. 2025; Ran et al. 2023; Zhao et al. 2023, 2024). Consequently, there is still a need for data that describe CPSP components and pain topography in specific clinical settings such as VATS in the elderly. To address these gaps, we designed a study to evaluate whether programmed intermittent paravertebral bolus infusion reduces the incidence of CPSP at three months postoperatively in elderly patients undergoing VATS. Besides, we also explored the components of neuropathic pain and the pain area localization postoperatively.
Methods
Study design and participants
This observational study included 242 elderly patients who underwent thoracic surgery at Beijing Chest Hospital, Capital Medical University, from February 2023 to April 1, 2024. Patients received either programmed intermittent paravertebral bolus infusion (Group P) or patient-controlled intravenous analgesia (Group I). Group assignment was based on routine clinical practice rather than randomization.
The inclusion criteria for this study were as follows: (1) age 60–75 years; (2) ASA I-III; (3) thoracoscopic surgery; (4) no severe cardiovascular or cerebrovascular disease; (5) conscious and able to communicate effectively; (6) written informed consent; and (7) no oral analgesics before surgery. The exclusion criteria included: (1) reoperation for severe surgical complications; (2) drug allergy; or (3) cancer metastasis/recurrence or death within 3 months. All eligible patients were evaluated by a trained anesthesiologist. The study adhered to the principles of the Helsinki Declaration.
Anesthesia and study procedures
Before the induction of anesthesia, a proficient anesthesiologist, employing ultrasound guidance, skillfully inserted a catheter into the T5-T6 paravertebral space. Subsequently, patients in Group P received a paravertebral regional block consisting of a single bolus injection of 20 mL of 0.5% ropivacaine through the paravertebral catheter. Patients in Group I did not receive any regional block. All patients received general anesthesia as usual during the procedure, administered via a double-lumen endotracheal tube. For thoracoscopic surgery, it is routine for the surgeon to place a drainage tube at the level of T5-T6. The analgesic pump was initiated postoperatively in both groups. All patients were treated with ondansetron to prevent postoperative nausea and vomiting. Ketorolac 30 mg was administered intravenously every 24 h for the first three days after surgery in both groups. Rescue analgesia was provided by intramuscular injection of 10 mg morphine.
Postoperative analgesic pump settings:
Paravertebral Group (Group P): A total of 300 mL of 0.2% ropivacaine was administered, starting with an initial dose of 15 mL after surgery, followed by 15 mL injections at 3-hour intervals. Additionally, a patient-controlled dose of 5 mL was available, with a lockout interval of 30 min.
Intravenous Group (Group I): A total of 100 mL of sufentanil at a concentration of 1.5 µg/kg was administered continuously at a rate of 1 mL/h. Additionally, a patient-controlled bolus dose of 2 mL was available, with a lockout interval of 15 min.
We analyzed the electronic medical records of each patient to obtain detailed demographic and clinical data. Additionally, we collected information on the use of opioid medications and other treatments for postoperative pain relief. Numerical Rating Scale (NRS) pain scores and other pain-related data were assessed and recorded by the same anesthesiologist for each patient at the following time points: 1 to 3 days after surgery, and 1 and 3 months postoperatively.
Outcomes
The primary outcome was the incidence of CPSP at three months. Secondary outcomes included the following: (1) maximum NRS pain scores at rest, during coughing, and with activity on postoperative days 1, 2, and 3; (2) chronic pain intensity at one month postoperatively; (3) the impact of analgesic regimens on pain components and the locations where pain occurs; (4) length of postoperative hospital stay; (5) factors affecting the exacerbation or relief of pain at one and three months postoperatively; (6) the impact of pain on sleep behavior.
Pain assessment scales and relative questionnaire
CPSP in our study was defined according to the International Classification of Diseases (ICD-11) (Stamer et al. 2025). Pain intensity was assessed using standardized instruments and procedures: the Numerical Rating Scale (NRS) quantified pain on a 0–10 scale, where 0 = no pain, 1–3 = mild, 4–6 = moderate, and 7–10 = severe. Neuropathic pain was screened using the ID Pain Scale, which includes five 5 sensory descriptors (pins/needles, hot/burning, numbness, electric shocks, worsened by touch), each scored as 1 point, and one joint pain exclusion item that subtracts 1 point if the pain was joint-specific. Total scores range from − 1 to 5, with scores ≥ 3 indicating probable neuropathic pain. Additionally, a structured questionnaire was used to document the location of pain, aggravating and alleviating factors, and the presence of paresthesia.
Statistical analysis
Statistical analyses were performed using IBM SPSS Statistics 26 software. Values were presented as medians (interquartile ranges) or as numbers (%). For comparisons between two groups, the Mann-Whitney U test was applied to quantitative variables (for skewed data) and the χ2 test was used to assess equality of proportions. Fisher’s exact test was employed for four-grid tables with a theoretical frequency of less than 5. Two-sided p-values of less than 0.05 were considered statistically significant. Potential confounding was evaluated using a multivariable regression model adjusted for covariates believed to potentially influence the incidence of persistent pain at 3 months postoperatively, including sex. There were no missing data for any covariates included in the model.
Sample size
The sample size for this study was determined using PASS 2021 for a two-sided Z-test comparing proportions. Assuming 80% power and a significance level (α) of 0.05, we estimated a 15% absolute difference in the incidence of chronic postoperative pain between the programmed intermittent paravertebral bolus infusion group (Group P, P1 = 10%) and the intravenous analgesia group (Group I, P2 = 25%). Because paravertebral block techniques require greater operator expertise and additional preoperative preparation, intravenous analgesia was more commonly used at our institution, resulting in an imbalanced sample size (NP:NI = 1:2) during consecutive enrollment. With an allocation ratio of R = NI/NP = 2, the initial calculated sample sizes were 78 and 156 for Groups P and I, respectively (total N = 234). To account for potential participant dropout, the sample size was increased by 20% for each group, resulting in final enrollment targets of 98 patients in Group P and 195 patients in Group I (total N = 293). This adjustment ensures adequate power during follow-up.
Results
We initially evaluated a total of 324 patients, of whom 293 met the inclusion criteria. However, due to loss to follow-up or incomplete data from 51 patients, the final analysis included 242 patients. Table 1 presents the demographic and clinical characteristics of the study participants.
Table 1.
The demographic and clinical characteristics of the patients
| Group P (n = 85) | Group I (n = 157) | p-valuea, b | |
|---|---|---|---|
| Age in years, M (P25, P75) | 67 (63.5, 69) | 67 (64, 69) | 0.691 |
| Sex ratio (male/female) | 54/31 | 64/93 | 0.001 |
| Mean BMI (SD) in kg/m² | 24.84 (2.76) | 24.43 (3.01) | 0.289 |
| Smoking history, n (%) | 38 (44.7) | 52 (33.1) | 0.075 |
| Chemotherapy, n (%) | 24 (28.2) | 37 (23.6) | 0.425 |
| Preoperative complications | |||
| Coronary heart disease, n (%) | 14 (16.5) | 30 (19.1) | 0.612 |
| Diabetes mellitus, n (%) | 30 (35.3) | 63 (40.1) | 0.461 |
| Hypertension, n (%) | 29 (34.1) | 49 (31.2) | 0.644 |
| ASA physical status | |||
| II | 71 | 119 | 0.162 |
| III | 14 | 38 | |
| Type of operation | |||
| Single-port VATS, n (%) | 30 (35.3) | 58 (36.9) | 0.809 |
| Double-port VATS, n (%) | 55 (64.7) | 99 (63.1) | 0.799 |
| Extent of the procedure | |||
| Wedge resection, n (%) | 48 (56.5) | 72 (45.9) | 0.115 |
| Lobectomy, n (%) | 26 (30.6) | 67 (42.7) | 0.065 |
| Bilobectomy or pneumonectomy, n (%) | 11 (12.9) | 18 (11.5) | 0.736 |
| Mild preoperative pain, n (%) | 12 (14.1) | 30 (19.1) | 0.328 |
| Periarthritis of shoulder, n (%) | 5 (5.9) | 5 (3.2) | 0.328c |
| Chest pain, n (%) | 1 (1.2) | 2 (1.3) | 1.000 |
| Neck pain, headaches, rheumatic pain and arthritic symptoms, n (%) | 7 (8.2) | 24 (15.3) | 0.117 |
| Other surgical data | |||
| Procedure duration (min), M (P25, P75) | 120 (82, 160) | 127 (93.5, 166) | 0.249 |
| Blood loss (mL), M (P25, P75) | 50 (20, 100) | 50 (20, 100) | 0.869 |
| Duration of chest tube (d), M (P25, P75) | 3 (3, 5) | 4 (3, 5) | 0.833 |
| Post-operative hospital stay (d), M (P25, P75) | 8 (7, 9) | 8 (7, 10) | 0.440 |
Abbreviations: M (P25, P75), the median (P25, P75); BMI Body Mass Index, SD standard deviation, ASA American Society of Anesthesiologists, VATS video-assisted thoracoscopic surgery
a: p-value compares programmed intermittent paravertebral bolus infusion versus intravenous analgesia; b: Mann-Whitney U test and t-test used to compare means and Pearson’s chi-square test is used for four-grid tables with theoretical frequencies greater than 5; c: Fisher’s exact test is used for four-grid tables with a theoretical frequency of less than 5
Paravertebral block in acute and chronic postoperative pain management
The primary outcome of the study demonstrated that patients receiving patient-controlled intermittent paravertebral analgesia had a lower incidence of chronic pain at three months postoperatively compared to Group I (3.5% versus 13.4%, p = 0.014) (Table 2). Considering sex as a factor influencing chronic pain, a multifactorial regression analysis was conducted including both sex and paravertebral analgesia. The results indicated that paravertebral analgesia (OR = 0.264 [0.075, 0.927], p = 0.038) remained a protective factor against chronic pain (Table 3).
Table 2.
Acute pain intensity and chronic pain incidence
| Group P (n = 85) | Group I (n = 157) | p-valuea, b | |
|---|---|---|---|
| During the first 3 days after surgery, n (%) | |||
| Resting NRS score | |||
| <4 | 24(28.2) | 40(25.5) | 0.642 |
| 4 ~ 6 | 60(70.6) | 110(70.1) | 0.932 |
| >6 | 0 | 5(3.2) | 0.165c |
| Moving NRS score | |||
| <4 | 0 | 0 | |
| 4 ~ 6 | 42(49.4) | 90(57.3) | 0.238 |
| >6 | 39(45.9) | 56(35.7) | 0.120 |
| Coughing NRS score | |||
| <4 | 2(2.4) | 5(3.2) | 1c |
| 4 ~ 6 | 61(71.8) | 113(72.0) | 0.972 |
| >6 | 21(24,7) | 35(22.3) | 0.671 |
| Chronic pain at 1 month, n (%) | 22(25.9) | 45(28.7) | 0.645 |
| Chronic pain at 3 months, n (%) | 3(3.5) | 21(13.4) | 0.014 |
a: p-value compares programmed intermittent paravertebral bolus infusion versus intravenous analgesia; b: Pearson’s chi-square test is used for four-grid tables with theoretical frequencies greater than 5; c: Fisher’s exact test is used for four-grid tables with a theoretical frequency of less than
Table 3.
Multifactorial regression analysis of the primary outcome
| Statistics | OR | 95% CI | p-valuea, b | |
|---|---|---|---|---|
| Sex, n (%) | 0.604 | (0.244, 1.498) | 0.276 | |
| Male | 8(33.3) | |||
| Female | 16(66.7) | |||
| Paravertebral analgesia, n (%) | 3(12.5) | 0.264 | (0.075, 0.927) | 0.038 |
Abbreviations: CI confidence interval, OR odds ratio
a: p-value compares continuous paravertebral block versus intravenous analgesia; b: Multivariate logistic regression analysis was used to control for confounding bias
In the first three days postoperatively, there were no significant differences in the NRS pain scores at rest, during coughing or activity between Group P and Group I (Fig. 1). In Group P, 22 patients (25.9%) experienced pain persisting for more than one month, and 3 patients (3.5%) developed chronic pain lasting more than three months. In contrast, in Group I, 45 patients (28.7%) experienced pain persisting for more than one month, and 21 patients (13.4%) developed chronic pain lasting more than three months (Table 2). These findings indicate that paravertebral analgesia has beneficial effects in reducing chronic pain three months postoperatively.
Fig. 1.
The maximum resting NRS pain scores between two groups on postoperative 1–3 days, 1 month, and 3 months. Abbreviations: NRS, numerical rating scale; POD, Postoperative days. Error Bar represent the 95% confidence intervals
Paravertebral block and pain area
In patients undergoing thoracic surgery, pain may be localized near the incision and can manifest on either the anterior or posterior aspects of the surgical site. Additionally, due to the distribution characteristics of intercostal nerves, referred pain may also present in regions such as the axilla, shoulder, back, and arm. Notably, female patients who undergo thoracic surgery frequently report pain and discomfort in the breast region. This study found that, among elderly thoracic surgery patients, there was no significant difference between Group P and Group I in the occurrence of pain in the posterior aspect of the incision, axilla, back, breast, and arm (as shown in Fig. 2; Table 4). At one month postoperatively, Group P had a lower incidence of anterior chest pain compared to Group I (34.1% versus 52.9%, p = 0.005). However, Group P exhibited a higher incidence of shoulder pain (21.2% versus 10.8%, p = 0.029). At three months postoperatively, Group P continued to have a lower incidence of anterior chest pain compared to Group I (22.4% versus 36.9%, p = 0.020). The incidences of shoulder pain in the two groups were 12.9% and 8.9%, with no significant difference. These findings illustrate the variations in pain distribution across distinct anatomical regions following thoracic surgery and the impact of paravertebral analgesia on these pain patterns.
Fig. 2.
The postoperative chest, shoulder and back pain between two groups. The darker the color of the corresponding body part, the higher the likelihood of pain
Table 4.
Comparison of different pain area
| Group P (n = 85) | Group I (n = 157) | p-valuea, b | |
|---|---|---|---|
| Pain area at 1 month, n (%) | |||
| Around the incision | 59(69.4) | 103(65.6) | 0.548 |
| Anterior chest | 29(34.1) | 83(52.9) | 0.005 |
| Posterior chest | 2(2.4) | 5(3.2) | 1.000c |
| Axilla | 3(3.5) | 5(3.2) | 1.000c |
| Shoulder | 18(21.2) | 17(10.8) | 0.029 |
| Back | 30(35.3) | 69(43.9) | 0.191 |
| Breast | 14(16.5) | 42(26.8) | 0.070 |
| Arm | 1(1.2) | 6(3.8) | 0.427c |
| Pain area at 3 months, n (%) | |||
| Around the incision | 50(58.8) | 83(52.9) | 0.374 |
| Anterior chest | 19(22.4) | 58(36.9) | 0.020 |
| Posterior chest | 3(3.5) | 3(1.9) | 0.426c |
| Axilla | 2(2.4) | 5(3.2) | 1.000c |
| Shoulder | 11(12.9) | 14(8.9) | 0.326 |
| Back | 19(22.4) | 42(26.8) | 0.452 |
| Breast | 11(12.9) | 28(17.8) | 0.323 |
| Arm | 0 | 4(2.5) | 0.301c |
a: p-value compares programmed intermittent paravertebral bolus infusion versus intravenous analgesia; b: Pearson’s chi-square test is used for four-grid tables with theoretical frequencies greater than 5; c: Fisher’s exact test is used for four-grid tables with a theoretical frequency of less than 5
Paravertebral block and pain components
We subsequently characterized postoperative pain features following thoracic surgery, including pain descriptors and sensory symptoms such as pricking, visceral pain, hyperesthesia, numbness, and electric shock-like sensations. These symptoms, along with neuropathic pain (ID Pain score ≥ 3), were assessed using the ID Pain scale and a structured questionnaire (Table 5). At one month postoperatively, there were no statistically significant differences between the two groups regarding pain characteristics or the prevalence of neuropathic pain. However, at three months postoperatively, Group P exhibited a lower incidence of pricking pain and hyperesthesia compared to Group I (22.4% versus 36.5%, p = 0.024; 24.7% versus 37.6%, p = 0.042). Additionally, Group P had a lower incidence of neuropathic pain than Group I (24.7% versus 39.5%, p = 0.021). These findings highlight differences in postoperative pain characteristics and suggest a potential impact of paravertebral analgesia on specific pain components and sensory abnormalities.
Table 5.
Comparison of quality of pain and sensory symptoms
| Group P (n = 85) | Group I (n = 157) | p-valuea, b | |
|---|---|---|---|
| Different quality of pain and sensory symptoms at 1 month, n (%) | |||
| Pricking (pins/needles) | 20(23.5) | 46(29.3) | 0.336 |
| Visceral pain | 13(15.3) | 26(16.6) | 0.798 |
| Hyperesthesia (worsened by touch) | 41(48.2) | 73(46.5) | 0.796 |
| Numbness | 39(45.9) | 63(40.1) | 0.387 |
| Electric shock-like sensations | 2(2.4) | 4(2.5) | 1.000c |
| Neuropathic pain (ID pain scores ≥ 3) | 33(38.8) | 58(36.9) | 0.773 |
| Different quality of pain and sensory symptoms at 3 months, n (%) | |||
| Pricking (pins/needles) | 19(22.4) | 57(36.5) | 0.024 |
| Visceral pain | 14(16.5) | 18(11.5) | 0.272 |
| Hyperesthesia (worsened by touch) | 21(24.7) | 59(37.6) | 0.042 |
| Numbness | 32(37.6) | 66(42.0) | 0.507 |
| Electric shock-like sensations | 6(7.1) | 2(1.3) | 0.024c |
| Neuropathic pain (ID pain scores ≥ 3) | 21(24.7) | 62(39.5) | 0.021 |
a: p-value compares programmed intermittent paravertebral bolus infusion versus intravenous analgesia; b: Pearson’s chi-square test is used for four-grid tables with theoretical frequencies greater than 5; c: Fisher’s exact test is used for four-grid tables with a theoretical frequency of less than 5
Paravertebral analgesia and poor prognosis and pain aggravation relief factors
The findings of this study highlight the multifactorial influences on postoperative pain and patient outcomes following thoracic surgery. In the early postoperative period, patients receiving intravenous analgesia may experience adverse effects associated with opioid medications, including nausea and vomiting. Postoperative patients are also vulnerable to complications such as pain, delayed wound healing, and pulmonary complications like atelectasis or pleural effusion. Additionally, persistent pain can negatively impact sleep quality. The study found that Group P had a lower incidence of nausea and vomiting compared to Group I (13.1% versus 30.1%, p = 0.003) during the first three postoperative days. At three months postoperatively, patients in Group I were more likely to experience exacerbation of pain after activity or coughing compared to Group P (22.9% versus 9.4%, p = 0.009). No significant differences were observed between the two groups regarding other adverse outcomes or relevant factors (Table 6). These findings underscore the importance of effective pain management and addressing associated complications in thoracic surgery patients to improve postoperative outcomes and quality of life.
Table 6.
Aggravating or relieving factors of pain and complications
| Item | Group P (n = 85) | Group I (n = 157) | p-valuea,b |
|---|---|---|---|
| Aggravating or relieving factors, n (%) | |||
| At 1 month | |||
| Overcast day | 6(7.1) | 24(15.3) | 0.064 |
| Moving or coughing | 31(36.5) | 58(36.9) | 0.942 |
| Pain treatment | 4(4.7) | 19(12.1) | 0.061 |
| Opioids | 1(1.2) | 4(2.5) | 0.660c |
| NSAIDs, physical therapy or the typical TCM | 3(3.5) | 15(9.6) | 0.088 |
| Difficulty sleeping | 13(15.3) | 23(14.6) | 0.893 |
| At 3 months | |||
| Overcast day | 8(9.4) | 22(14.0) | 0.300 |
| Moving or coughing | 8(9.4) | 36(22.9) | 0.009 |
| Pain treatment | 11(7.0) | 1(1.2) | 0.061c |
| Opioids | 0 | 4(2.5) | 0.301c |
| NSAIDs, physical therapy or the typical TCM | 1(1.2) | 7(4.5) | 0.267c |
| Difficulty sleeping | 1(1.2) | 6(3.8) | 0.427c |
| Complications, n (%) | |||
| Nausea and vomiting during the first 3 days postop | 11(13.1) | 47(30.1) | 0.003 |
| Pulmonary complications at 1 month | 1(1.2) | 8(5.1) | 0.166c |
| Pulmonary complications at 3 months | 1(1.2) | 4(2.5) | 0.660c |
Abbreviations: TCM traditional Chinese medical, NSAIDs Nonsteroidal Anti inflammatory Drugs, postop, postoperative
a: p-value compares programmed intermittent paravertebral bolus infusion versus intravenous analgesia; b: Pearson's chi-square test is used for four-grid tables with theoretical frequencies greater than 5; c: Fisher's exact test is used for four-grid tables with a theoretical frequency of less than 5
Discussion
Pain is a complex sensory experience involving multiple dimensions. However, there is a lack of extensive research on the composition and effects of different types of postoperative pain (Hetmann et al. 2017). Our study demonstrated that patients receiving programmed intermittent paravertebral bolus infusion had a lower incidence of chronic pain three months postoperatively. This study focused not only on the incidence of chronic pain but also on the components and characteristics of chronic pain responses influenced by regional blockade in elderly patients. Group P exhibited a lower incidence of neuropathic pain, anterior chest pain, and pinprick sensation, as well as a reduced incidence of pain triggered by activity or coughing at 3 months post-surgery compared to Group I.
A previous study investigating the significance of various components of acute and chronic pain responses following thoracic surgery revealed that chest pain was the only component significantly associated with post-thoracotomy pain syndrome (Blichfeldt-Eckhardt et al. 2018) while shoulder pain and referred pain were not statistically significant. Interestingly, our study observed a similar phenomenon (Cazzaniga et al. 2024). Moreover, our findings demonstrated that paravertebral analgesia effectively reduced anterior chest pain at one and three months after surgery. Acute postoperative pain is very common after thoracic surgery. Acute pain arises from noxious stimuli activating peripheral nociceptors (Schug et al. 2011), but persistent injury induces maladaptive neuroplasticity in both the peripheral and central nervous systems (Zhang et al. 2025), leading to chronic pain phenotypes characterized by spontaneous ectopic discharges and expanded receptive fields (Dickenson 2016). Anatomically, the preferential somatic nerve blockade achieved by paravertebral blockade may explain the reduction in incisional pain, whereas spared phrenic nerve activation could contribute to persistent shoulder discomfort (Hung et al. 2022).
Programmed intermittent paravertebral bolus infusion at a rate of 15 ml/ 3 h in this study appeared effective in promoting the distribution of the solution within the paravertebral space. Kim et al. found that injecting 10 mL of dye into the paravertebral space was sufficient to stain the sympathetic chain, with 93.75% (15/16) spreading to the anterior nerve branches (Kim et al. 2024). Rusciod et al. found that the average number of TPVS stained by an injection of 13 mL of staining solution ranged from 2.2 to 2.7 (Ruscio et al. 2020). Using MRI after ultrasound-guided TPVB with 20 mL of local anesthetic at the T6 level, Marhofer et al. observed an average cranio-caudal spread of approximately four vertebral levels. However, the sensory block extended to about ten dermatomes, suggesting that clinical coverage may exceed the spread observed on imaging (Marhofer et al. 2013). In this study, the surgical incisions were primarily located between the second and fifth intercostal spaces, and postoperative analgesia was achieved through programmed intermittent injection of 15 mL of 0.2% ropivacaine via a pump into the paravertebral space at T5 or T6, thereby ensuring effective regional blockade and minimizing breakthrough pain.
Notably, postoperative shoulder pain appears to be more common among patients aged over 65 years (Sayed et al. 2023). In our study, the prevalence of shoulder pain was higher in Group P at one month post-surgery (35% vs. 21%, p = 0.04). Two potential causes of ipsilateral shoulder pain following thoracic surgery have been identified: shoulder ligament strain and phrenic nerve-related pain (Bamgbade et al. 2007; Sayed et al. 2023). Similarly, it has been demonstrated that thoracic epidural block effectively mitigates incisional pain but is not effective in managing shoulder pain (Barak et al. 2004). Anatomically, the preferential somatic nerve blockade provided by paravertebral blockade may explain the reduction in incisional pain, whereas spared phrenic nerve activation could contribute to persistent shoulder discomfort. Further investigation is warranted to elucidate the underlying factors contributing to the increased prevalence of shoulder pain following thoracic surgery.
Although our study yielded interesting findings, it was subject to certain limitations. Specifically, detailed pain information during the initial three-day period following surgery was not included. While it is critically important to differentiate among the neurological, visceral, and somatic components of acute postoperative chest pain, collecting comprehensive data on pain components during the early postoperative period (days 1–3) can be challenging. This difficulty arises because patients often struggle to distinguish between different pain elements caused by pain stimuli and the effects of analgesic medications. Consequently, a questionnaire designed to systematically gather detailed pain data during the immediate postoperative acute pain phase was not incorporated into the study design. Furthermore, it is important to note that our investigation was conducted as a single-center observational study. Since group assignment followed routine clinical practice rather than randomization, baseline imbalances may have occurred, including a significant difference in sex distribution between groups. Sex is a clinically relevant factor for chronic pain outcomes (Smith et al. 2025); therefore, we adjusted for sex in the multivariable regression model. However, unmeasured or incompletely captured confounders related to treatment selection and sex-specific pain vulnerability may still remain. Despite these limitations, this study provides important evidence supporting paravertebral blockade as a viable strategy for reducing CPSP in elderly thoracic surgery patients.
Clinically, these findings underscore the importance of tailoring analgesic regimens to pain phenotypes (Cho et al. 2021). Several preliminary studies suggest that implementing multimodal analgesia strategies in conjunction with paravertebral block may be associated with a reduced incidence of chronic pain (Pace et al. 2016). Additionally, the effects of a single preoperative paravertebral block, programmed intermittent paravertebral bolus infusion, and postoperative paravertebral block on alleviating acute postoperative pain differ, and these effects have not been fully investigated (Liu et al. 2022). Therefore, further research is necessary to determine the optimal practices for paravertebral analgesia.
Conclusions
Chronic postoperative pain is a common complication following thoracic surgery. Programmed intermittent paravertebral bolus infusion seems to reduce the incidence of chronic pain and neuropathic in patients undergoing thoracoscopic surgery. Further research is needed to explore the potential benefits of combining multimodal analgesia with programmed intermittent paravertebral bolus infusion.
Acknowledgements
We would like to express our gratitude to the Beijing Chest Hospital, Capital Medical University, and the Beijing Tuberculosis and Thoracic Tumor Research Institute. We would also thank all the anesthesiologists and other medical professionals who participated in this research for their valuable assistance.
Authors’ contributions
Conception and design: LW, TL, WL, WLK. Administrative support: WL. Provision of study materials or patients: GKG, TL, BC, WL. Collection and assembly of data: LW, YCS. Data analysis and interpretation: LW, WL. K. Manuscript writing: LW, YCS, GKG, TL, BC, WLK, WL. Final approval of manuscript: LW, YCS, GKG, TL, BC, WLK, WL.
Funding
None.
Data availability
All data generated or analysed during this study are included in this published article and its supplementary information files.
Declarations
Ethics approval and consent to participate
This work has been carried out in accordance with the Declaration of Helsinki (2000) of the World Medical Association. This work was approved by the Ethics Committee of Beijing Chest Hospital Affiliated to Capital Medical University (No: 2022-27).
Consent for publication
Not applicable.
Competing interests
The authors declare no competing interests.
Footnotes
Publisher’s note
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Data Availability Statement
All data generated or analysed during this study are included in this published article and its supplementary information files.