Liposomal Bupivacaine Cut Opioid Use After Lumbar Fusion

Key Takeaways

• Among adults undergoing one- or two-level posterior lumbar decompression and fusion, an LB-based combined wound infiltration regimen was associated with a significant 22% reduction in 72-hour opioid use versus ropivacaine.
• The opioid-sparing effect was most evident from 8 to 48 hours after surgery, especially during the 8 to 24 hour and 24 to 48 hour intervals, with no significant difference at the earliest or latest intervals.
• Overall postoperative pain burden was lower with the LB-based combined regimen at rest and with movement, including lower 72-hour pain AUC.
• Worst postoperative NRS pain was lower with the LB-based combined regimen, although supportive pairwise comparisons at individual assessment time points were not significant.
• Rescue analgesia use, adverse events, and short-term functional recovery outcomes did not differ significantly between groups.

Matching wound infiltration duration to the peak pain window after lumbar fusion remains a practical analgesia problem during the first postoperative days, when opioid exposure is often highest. At a tertiary spine center, investigators tested whether an extended-release local anesthetic strategy could better cover that early recovery period than ropivacaine over the first 72 hours after surgery.

In the randomized lumbar fusion trial of liposomal bupivacaine–based infiltration versus ropivacaine, investigators at Peking University Third Hospital conducted a single-center, prospective, randomized, controlled trial with patients and outcome assessors blinded; treating anesthesiologists and surgeons were not fully blinded because the liposomal bupivacaine (LB) suspension had a distinct appearance. Eligible participants were adults older than 18 years with American Society of Anesthesiologists (ASA) class I to III undergoing elective one- or two-level posterior lumbar decompression and fusion with internal fixation for degenerative spinal disease and planned intravenous patient-controlled analgesia (PCA). The trial randomized 204 patients, with 202 included in the modified intention-to-treat analysis and 198 in the per-protocol analysis. Bilateral infiltration before wound closure targeted paraspinal muscles and subcutaneous tissues and compared LB 266 mg plus 25 mg plain bupivacaine with ropivacaine 120 mg, while all patients received standardized multimodal perioperative analgesia and morphine PCA for 72 hours. The primary endpoint was cumulative 72-hour opioid consumption expressed as morphine milligram equivalents (MME).

Cumulative 72-hour opioid consumption was 43.0 (37.0, 58.0) mg in the LB-based group and 58.0 (46.0, 73.0) mg with ropivacaine, with a geometric mean ratio (GMR) of 0.78 and 95% confidence interval (CI) 0.71 to 0.85; p<0.001. Repeated-measures analysis across postoperative intervals also favored the LB-based regimen overall, with GMR 0.81, 95% CI 0.73 to 0.89; p<0.001. The group-by-time interaction was significant at p=0.027. The clearest interval differences were during 8 to 24 hours, with GMR 0.70, 95% CI 0.58 to 0.83; p<0.001, and 24 to 48 hours, with GMR 0.70, 95% CI 0.58 to 0.84; p<0.001. The 0 to 4 hour, 4 to 8 hour, and 48 to 72 hour intervals were not significantly different.

Overall pain scores were lower with the LB-based regimen at rest, with GMR 0.80, 95% CI 0.68 to 0.94; p=0.007, and with movement, with GMR 0.84, 95% CI 0.75 to 0.93; p=0.001. Over 72 hours, pain area under the curve (AUC) was also lower at rest, with a mean difference (MD) of -19.9, 95% CI -36.1 to -3.7; p=0.017, and with movement, with MD -38.8, 95% CI -60.6 to -17.0; p<0.001. Worst postoperative numerical rating scale (NRS) pain was 4 (4,5) versus 5 (4,6), with a Hodges-Lehmann median difference of -1.0, 95% CI -1.0 to 0.0; p=0.001. Supportive pairwise between-group comparisons at individual pain-assessment time points were not significant. Rescue analgesia use, adverse events, and short-term functional recovery outcomes were not significantly different, and no local anesthetic-related or wound-related complications, desaturation, or deep sedation were observed.

The authors noted several constraints on interpretation: the trial was conducted at a single center, treating clinicians were not completely blinded, follow-up did not extend beyond discharge, exploratory subgroup analyses were not powered for subgroup comparisons, and the low event rate limited strong safety comparisons. They also emphasized that the observed signal applies to an LB-based combined infiltration regimen that included added plain bupivacaine rather than to LB monotherapy.

The authors concluded that, in this lumbar fusion population, bilateral infiltration with liposomal bupivacaine plus plain bupivacaine was associated with lower postoperative opioid exposure and lower cumulative pain burden than ropivacaine, without a detected short-term penalty in adverse events or early functional recovery.

Clinician Questions

When after lumbar fusion was opioid reduction greatest with liposomal bupivacaine–based infiltration?

In adults undergoing posterior lumbar decompression and fusion, the randomized comparison of an LB-based combined infiltration regimen versus ropivacaine found the greatest opioid reduction during 8 to 24 hours and 24 to 48 hours after surgery, with no significant between-group differences during 0 to 4 hours, 4 to 8 hours, or 48 to 72 hours.

Was the lumbar fusion regimen liposomal bupivacaine alone or a combined local anesthetic protocol?

In adults undergoing posterior lumbar decompression and fusion, the intervention was a combined bilateral infiltration protocol of liposomal bupivacaine 266 mg plus 25 mg plain bupivacaine given before wound closure and compared with ropivacaine 120 mg. The randomized lumbar fusion trial did not test liposomal bupivacaine monotherapy against ropivacaine.

Did liposomal bupivacaine–based infiltration lower postoperative pain scores after posterior lumbar decompression and fusion?

In adults undergoing posterior lumbar decompression and fusion, the trial reported lower overall pain scores at rest and with movement, lower 72-hour pain AUC for both rest and movement, and a lower worst postoperative NRS pain score with the LB-based combined regimen. The authors also noted that supportive pairwise between-group comparisons at individual assessment time points were not significant.

Were adverse events or short-term recovery outcomes different after liposomal bupivacaine–based infiltration in lumbar fusion?

After one- or two-level posterior lumbar decompression and fusion, the trial found no significant between-group differences in rescue analgesia, adverse events, or short-term functional recovery with liposomal bupivacaine–based infiltration versus ropivacaine. No local anesthetic-related complications, wound-related complications, desaturation, or deep sedation were observed, although the low event rate limited firm conclusions about safety differences.