Place of the paravertebral block in post-operative analgesia in thoracic surgery

The thoracic epidural analgesia (TEA) remains the standard gold for analgesic support in thoracic surgery, there is an interesting alternative to epidural analgesia, which is the paravertebral block (PVB). The aim in our study was to assess the value of performing a PVB in the management of postoperative pain in thoracic surgery compared to TEA. Methods: 80 patients were randomized to receive either epidural analgesia (n = 38, 10 cc bupivacaine 0.5% + 10 ϒ Sufentanyl then 10 cc Bupivacain 0.1% + 10 ϒ Sufentanyl via a PCA device) or PVB analgesia loss of resistance technique (n = 40, 10 cc bupivacaine 0.5% + 10 ϒ Sufentanyl via a PCA device). All patients received standard general anesthesia. The peri-operative parameters studied include standard measurement, EVA scale at rest and mobilization, use of morphinics. Results: there is a significant difference between the two groups and the incidents of puncture were significantly more important for the APDT group. The postoperative pain assessment by EVA did not show a significant difference between TEA and PVB Conclusion: the comparison of PVB to TPDA did not find significant difference in the efficacy of analgesia and the side effects. The BPV could be proposed as a first intention for postoperative analgesia in thoracic surgery.


Introduction:
Thoracic surgery is one of the surgeries leading to severe postoperative pain. Thoracotomy is a surgical approach that generates acute pain of major intensity and for a prolonged period [1][2], but also at a distance with a risk of chronicization [3]. This acute pain, increases the metabolic demand of the operated on and has a direct consequence on its ventilatory mechanics and can induce serious complications. In addition, chronic pain, most often neuropathic [4], is frequent after this type of surgery and is directly related to the intensity of acute postoperative pain [5]. The postoperative analgesia must be optimal in order to ensure early rehabilitation and prevent the onset of chronic pain. A multimodal perioperative analgesia strategy is necessary. Thoracic epidural analgesia (TEA) remains the "gold standard" for analgesic management in this context [6][7].
Postoperatively, the benefit of epidural analgesia is demonstrated by optimal analgesic coverage, improvement of diaphragmatic contractility, optimization of compliance with respiratory exercises, reduction of respiratory failures, reduction of the length of stay and a decrease in the incidence of chronic pain [3]. However, this technique requires good mastery and exposes in particular to the risk of direct spinal cord injury. The most attractive alternative to an epidural is paravertebral block (BPV) [13]. Recent data in the literature suggest comparable analgesic efficacy between thoracic epidural. The aim of our study was assessing the value of performing a paravertebral block as part of the management of postoperative pain in thoracic surgery in comparison to thoracic epidural analgesia

Materials and methods:
This are a prospective, descriptive, randomized singleblind study and monocentric carried out within the Thoracic Surgery department of Bab-El-Oued CHU in Algiers over a period of 24 months from October 2012 to October 2014

Population:
Our population consisted of 80 adult patients over the age of 18, admitted to the service during the study period. These patients were classified ASA I to III and underwent posterolateral thoracotomy with informed consent of patients and agreement of the local ethics committee. Indications are diverse (lung cyst, pneumothorax, tumors, bronchial dilation, bronchogenic cysts, emphysema bubbles).

Inclusion criteria:
ASA class I, II, III patients, age ≥ 18 years old and the patient operated on for an anterolateral thoracotomy.

Exclusion criteria:
Refusal of the analgesia technique by the patient, local infection, allergy to local anesthetics (LA), pleurotomy planned, pleural pocket, patient with a hemostasis disorder or requiring the administration of an anticoagulant preoperatively or, receiving antiplatelet therapy, ASA IV patient and psychiatric pathology or patient with a limitation of his intellectual capacities

Randomization:
was done by random permutation tables, after admission: thoracic epidural group (TEA)and paravertebral block group (PVB). All patients received general anesthesia. Induction was made with propofol (1.5 -2.5 mg.kg-1) and fentanyl (3-5μg kg-1.) and curarization by vecuronium bromide (0.1 mg kg-1). No opioid dose supplemental intravenous therapy has not been given after induction. Maintenance was ensured by propofol (6 to 12 mg / kg / h in the syringe pump) or sevoflurane (1-2%) in combination with oxygen. All procedures were performed by surgeons using the same techniques with pose of 1 or 2 chest drains. All patients received postoperative supplemental analgesia with acetaminophen (Paracetamol®) and diclofenac.     Evaluation of postoperative pain by VAS did not show any significant difference between the two groups. Sensory levels in both groups were similar from T2-T3 to higher level than T8-T9 at lower level.

Adverse events:
MAP, SPO2, Mean HR, values were comparable in the two groups during the first 48 hours postoperatively.

Technical failures, side effects (PONV) and use of morphine
No significant difference was observed between the two groups of patients with regard to technical failures, side effects (PONV) and use of opioids.

Patient and surgeon satisfaction:
Patient and surgeon satisfaction were better in the APDT group, but the difference was not significant 3. Discussion: The origin of post-thoracotomy pain is complex [1-20-21