TAP Block Efficacy After Lumbar Spine Surgery Through Anterior Approach: a Randomized, Placebo-controlled Study

Analgesic Efficacy of Transversus Abdominis Plane (TAP) Block After Lumbar Spine Surgery Through Anterior Approach (Anterior Lumbar or Direct Lateral Interbody Fusion): a Prospective, Randomized, Double-blind Placebo-controlled Study

Anterior Lumbar Interbody Fusion (ALIF) as well as Direct Lateral Interbody Fusion (DLIF) are established techniques for lumbar interbody fusion. In contrast with posterior approaches, they allow free approach to the anterior disc space without opening of the spinal canal or the neural foramina. However, the additional anterior approach conveys specific concerns, including abdominal pain that may delay recovery after surgery. The transversus abdominis plane (TAP) block is a validated approach for postoperative pain relief following abdominal surgeries. There is currently no evidence of the possible benefits of TAP block as part of multimodal pain management after ALIF/DLIF surgery. The investigator hypothesize that a single-injection TAP block reduces opioid consumption after anterior lumbar fusion surgery. The main goal of this prospective, randomized, double-blind, placebo-controlled study is to demonstrate a >35% reduction in opioid consumption during the 24h following ALIF/DLIF surgery.

Clinical trial : therapeutic, prospective, randomized,double blind, placebo-controlled, with parallel group, of superiority, in intention to treat, monocentric study.

The main steps of the study are:

• preoperative assessment of eligibility
• exclusion and inclusion criteria, written informed consent, baseline preoperative assessment (see specific section)
• randomization (using a computer generated list) immediately before induction of anesthesia
• TAP block: ropivacaine + clonidine (experimental group, n=20) OR saline (control group; n=20)
• anesthesia (propofol, sufentanil, cisatracurium, ketamine and desflurane) and postoperative analgesia (paracetamol, ketoprofen, nefopam, and patient-controlled analgesia with morphine) similar in both groups
• surgical procedure
• primary outcome parameter (morphine consumption first 24 hours; see specific section)
• secondary endpoints (see specific section, up to 6 months following surgery)

Inclusion Criteria:

• Man or woman over the age of 18 yr
• Patients with insurance coverage
• Patients able to provide free and informed consent
• Patients undergoing surgery by the ALIF or DLIF approaches

Exclusion Criteria:

• Patients receiving opioids as chronic treatment
• Patients with contra-indication to regional anesthesia or TAP block
• Patients unable to consent
• Patient refusal
• Patients with contra-indication to any drug included in the anesthesia or analgesia protocol
• Pregnancy or breast-feeding women