Erector Spinae Plane Block as Pain Management After Lumbar Fusion Surgery

Rationale: Lumbar spine surgery is associated with high postoperative pain scores and analgesic use, despite use of multimodal analgesia. The erector spinae plane block (ESPB) is a promising locoregional anesthetic technique for this type of surgery. The literature is not yet conclusive about the effectiveness of this technique on reducing postoperative pain intensity.

Objective: The objective of this study is to evaluate the analgesic effect of ESPB as add-on therapy to multimodal analgesia on early postoperative pain intensity after lumbar spinal fusion surgery compared to placebo.

Study design: The study is designed as a prospective mono-centre, randomized, double-blinded, placebo-controlled trial.

Study population: 76 patients ≥ 18 years of age requiring elective lumbar spinal fusion surgery involving one to four fusion levels.

Intervention: Patients will receive ultrasound-guided ESPB with either ropivacaine or placebo at the end of surgery.

Main study parameters/endpoints: Main study parameter is pain intensity upon emergence from anesthesia measured with the Numeric Rating Scale. A minimal clinically important difference is considered to be a decrease of 1.5 points. Secondary endpoints are pain intensity during hospital stay and after 30 days, opioid use during hospital stay and after 30 days, opioid side effects, use of anti-emetics, time to first opioid use/request, length of hospital stay, quality of recovery at discharge.

Nature and extent of the burden and risks associated with participation, benefit and group relatedness: The Sint Maartenskliniek is experienced in applying locoregional analgesia, the use of ropivacaine and using sonography. The procedure of administering ESPB has a very low risk of complications. Receiving placebo is justifiable because this group will not be withhold standard treatment. The risks of receiving placebo are negligible. The patients will visit the clinic at regular follow-up moments.

Rationale: Lumbar spine surgery is associated with high postoperative pain scores and analgesic use. Despite multimodal pain treatment, time to first rescue treatment with opioids is often short and necessary on the Post Anesthesia Care Unit (PACU). Latest scientific insights show most pain interventions produce mild analgesic effects, and advise a multimodal regimen based upon systemic analgesics consisting of at least gabapentoids, ketamine and opioids. Therefore, in our clinic (Sint Maartenskliniek, Nijmegen, the Netherlands), multimodal analgesia in spine surgery is now gold standard, with opioids as first choice postoperative rescue treatment. However, despite multimodal treatment, patients who underwent lumbar spine surgery still develop severe postoperative pain.

A different possible measure to lower the risk of postoperative pain is locoregional anesthesia. The Sint Maartenskliniek has a long history of applying locoregional anesthesia in orthopedic surgery. Locoregional anesthesia provides effective analgesia without systemic side-effects like drowsiness or nausea, thereby reducing perioperative systemic drug use and possibly reducing the risk of persistent postsurgical pain. A novel locoregional anesthetic technique is the erector spinae plane block (ESPB). Good quality evidence exists for the effectiveness of this technique in breast cancer surgery and video assisted thoracoscopy (VATS). Although ESPB seems a promising analgesic technique for lumbar spine surgery patients not responding to the multimodal pain treatment regimen, sufficient high quality evidence is lacking. A recent systematic review summarized the evidence of ESPB for lumbar spine surgery, including two randomized clinical trials (RCT), showing beginning evidence of reduced postoperative opioid consumption and decreased pain scores. However, these trials contained a small sample size, were not blinded or lacked a comparator. Furthermore, little information on postoperative hospital stay is provided. This results in ESPB not being widely accepted in lumbar spine surgery. The larger, double-blinded, placebo-controlled methodology in this proposed trial aims to contribute to the scientific evidence for the effectiveness of EPSB in a multimodal analgesia management setting.

Objective: The primary objective of the study is to evaluate the analgesic effect of ESPB on early postoperative pain after lumbar spinal fusion surgery. Therefore the pain intensity in the postoperative care unit upon emergence, using the Numeric Rating Scale (NRS) for pain, will be the primary outcome parameter of this study. The null hypothesis states there is no difference in effectiveness of the ESPB compared to placebo on early postoperative pain intensity measured with NRS in patients that underwent lumbar spinal fusion surgery. This hypothesis will be tested two-sided, with α = 0.05.

Study design: This study is designed as a prospective, mono-center, double-blinded, randomized, placebo controlled trial. The study will be performed at the Sint Maartenskliniek, Nijmegen, the Netherlands. The study will be performed in accordance with the ICH E6(R1) Good Clinical Practice (GCP) guidelines. The duration of the study will be determined according to the progress of inclusion. Patients scheduled for elective lumbar spinal fusion surgery will be studied. Subject of investigation is the locoregional anesthetic technique ESPB. Subjects will be randomized to receive either ESPB with a long-acting local anesthetic or normal saline (placebo).

The staff involved (doctors, nurses, OR-personal), as well as the research team and the patient will be blinded for treatment allocation. The study period includes in-hospital time after surgery and follow-up 30 days after surgery. Placement of the ESPB will be performed according to the study protocol, at the end of surgery, after wound closure. The placement of the ESPB is performed according to daily clinical practice as described by Forero et al. Postoperative treatment of patients will be according to standard hospital protocol for lumbar spinal fusion surgery.

Study population: 76 patients undergoing elective lumbar spinal fusion surgery involving one to four fusion levels will be recruited.

Main study parameters/endpoints: Main study parameter is pain intensity upon emergence from anesthesia measured with the Numeric Rating Scale. A minimal clinically important difference is considered to be a decrease of 1.5 points. Secondary endpoints are pain intensity during hospital stay and after 30 days, opioid use during hospital stay and after 30 days, opioid side effects, use of anti-emetics, time to first opioid use/request, length of hospital stay, quality of recovery at discharge.

Nature and extent of the burden and risks associated with participation, benefit and group relatedness: The Sint Maartenskliniek is experienced in applying locoregional analgesia, the use of ropivacaine and using sonography. The procedure of administering ESPB has a very low risk of complications. Receiving placebo is justifiable because this group will not be withhold standard treatment. The risks of receiving placebo are negligible. The patients will visit the clinic at regular follow-up moments.

Eligibility Criteria:
Inclusion Criteria:

* Age ≥ 18 years;
* Patients planned for elective lumbar spinal fusion surgery with a dorsal surgical approach;
* 1-4 fusion level spine surgery;
* Written informed consent.

Exclusion Criteria:

* A Body Mass Index (BMI) \> 40 kg/m²;
* ASA physical health classification \> 3;
* Patients who will undergo spine surgery involving less than 2 or more than 4 levels of fusion, scoliosis surgery\*;
* Patients who will undergo circumferent spine surgery;
* Patients with an active, local infection or systemic infection;
* Patients with an allergy to one or more medications used in the study;
* Patients with any contraindication to a regional anesthetic technique;
* Kidney- or liver failure inhibiting the systemic use of paracetamol and/or NSAIDs;
* Acute surgeries;
* Patients with a history of drugs or alcohol abuse;
* Pregnancy;
* Cognitive impairment;
* Inability to speak or understand the Dutch language.