Spinal anesthetic failure in patients undergoing elective hip and knee joint arthroplasty was associated with younger age, lower body mass index (BMI), needle insertion site, and needle size, according to study results published in Anesthesia & Analgesia.

Researchers retrospectively reviewed electronic anesthetic records of elective hip and knee replacements that were performed using spinal anesthesia. The review’s primary outcome was failure of spinal anesthetic after cerebrospinal fluid had been documented to flow back through the spinal needle. Variables examined included age, sex, height, BMI, surgical site, and needle gauge.

Of a total of 3542 spinal anesthesias examined, 135 failures (3.8%) were identified. A higher odds of failure was associated with younger age (odds ratio [OR], 1.03; 95% CI, 1.01-1.05), lower BMI (OR, 1.04; 95% CI, 1.01-1.08), hip arthroplasty vs knee arthroplasty (OR, 1.90; 95% CI, 1.28-2.84), needle insertion at L4-5 (OR, 4.61; 95% CI, 2.02-10.54) and L5-S1 (OR, 7.66; 95% CI, 2.47-23.7) vs L2-3, 22- vs a 25-gauge needle (OR, 2.17; 95% CI, 1.34-3.52), and hyperbaric bupivacaine vs isobaric bupivacaine (OR, 1.66; 95% CI, 1.09-2.53).

Study limitations include its retrospective design and the lack of objective tests for spinal failure.

“Further studies are needed to elucidate the reasons for these associations and the strategies to reduce the incidence of spinal failure,” noted the researchers.


Colish J, Milne AD, Brousseau P, Uppal V. Factors associated with failure of spinal anesthetic: an 8-year retrospective analysis of patients undergoing elective hip and knee joint arthroplasty published online July 9, 2019 Anesth Analg.