Spinal anesthesia is increasingly viewed as a reasonable alternative to general anesthesia for lumbar spine surgery. However, the results of spinal anesthesia in elderly patients undergoing lumbar spine decompression and combined decompression and fusion procedures are limited in the literature. The aim of this study was to report a single institution's experience using spinal anesthesia in elderly patients undergoing lumbar spine surgery. A retrospective review was conducted using a prospectively collected database of consecutive lumbar spine surgeries performed under spinal anesthesia in patients 70 years or older at a single center between December 2013 and October 2015. A total of 56 patients were included in the study; 27 patients (48%) underwent lumbar decompression and 29 patients (52%) underwent combined decompression and fusion procedures. Mean operative time was 101 minutes (range, 30-210 minutes), and mean operative blood loss was 187 mL (range, 20-700 mL). Mean maximum inpatient postoperative visual analog scale score was 6.2 (range, 1-10). Nausea occurred in 21% (12 of 56) of the patients. Mean length of stay was 2.4 days (range, 1-6 days). No mortality, stroke, permanent loss of function, or pulmonary embolism occurred. None of the cases required conversion to general anesthesia. All of the patients were ambulatory on either the day of the surgery or the next morning. These results demonstrate that spinal anesthesia is a viable method of anesthesia for patients 70 years and older undergoing lumbar spine surgery. They also demonstrate the safety of this method for patients older than 84 years and for surgeries lasting up to 3½ hours. [Orthopedics. 2017; 40(2):e317-e322.].
Background
Reducing depth of anesthesia and anesthetic exposure may help prevent delirium, but trials have been conflicting. Most studies were conducted under general anesthesia or in cognitively impaired patients. It is unclear whether reducing depth of anesthesia beyond levels consistent with general anesthesia reduces delirium in cognitively intact patients. The authors’ objective was to determine whether a bundled approach to reduce anesthetic agent exposure as determined by Bispectral Index (BIS) values (spinal anesthesia with targeted sedation based on BIS values) compared with general anesthesia (masked BIS) reduces delirium.
Methods
Important eligibility criteria for this parallel-arm randomized trial were patients 65 yr or greater undergoing lumbar spine fusion. The intervention group received spinal anesthesia with targeted sedation to BIS greater than 60 to 70. The control group received general anesthesia (masked BIS). The primary outcome was delirium using the Confusion Assessment Method daily through postoperative day 3, with blinded assessment.
Results
The median age of 217 patients in the analysis was 72 (interquartile range, 69 to 77). The median BIS value in the spinal anesthesia with targeted sedation based on BIS values group was 62 (interquartile range, 53 to 70) and in the general anesthesia with masked BIS values group was 45 (interquartile range, 41 to 50; P < 0.001). Incident delirium was not different in the spinal anesthesia with targeted sedation based on BIS values group (25.2% [28 of 111] vs. the general anesthesia with masked BIS values group (18.9% [20 of 106]; P = 0.259; relative risk, 1.22 [95% CI, 0.85 to 1.76]). In prespecified subgroup analyses, the effect of anesthetic strategy differed according to the Mini-Mental State Examination, but not the Charlson Comorbidity Index or age. Two strokes occurred among patients receiving spinal anesthesia and one death among patients receiving general anesthesia.
Conclusions
Spinal anesthesia with targeted sedation based on BIS values compared with general anesthesia with masked BIS values did not reduce delirium after lumbar fusion.
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