P140. Cost effectiveness analysis of spinal anesthesia versus general anesthesia in lumbar fusion surgery

Abstract

BACKGROUND CONTEXT Spinal anesthesia (SA) has been shown in several studies to be a viable alternative to general anesthesia (GA) in laminectomies, discectomies and microdiscectomies. However, the use of SA in spinal fusion surgery has been very scarcely documented in the current literature. Here we present a comparison of SA to GA in lumbar fusion surgery in terms of perioperative outcomes and cost. PURPOSE The objective of this study was to compare the cost and outcomes of SA and GA in minimally invasive transforaminal lumbar interbody fusion (TLIF) to demonstrate their relative cost-effectiveness. STUDY DESIGN/SETTING Patients undergoing minimally invasive TLIF were included in the study. Patients were stratified into two groups based on anesthetic modality: general anesthesia or spinal anesthesia. The setting of the study was a suburban, tertiary-care level university-affiliated hospital. PATIENT SAMPLE A total of 75 patients underwent minimally invasive TLIF surgery, 36 males and 39 females with an age range of 20 to 87 years old. The main diagnoses for these patients were spondylolisthesis (58 patients) and spinal stenosis (57 patients), while degenerative disc disease (5) and herniated discs (3) were less commonly seen, with many patients having multiple diagnoses. OUTCOME MEASURES The authors recorded patient demographic information, BMI, diagnosis, comorbidities, levels operated on, total OR time, total surgery time (incision to closure), time under anesthesia, post-anesthesia care unit (PACU) time, pain scores, adverse events, nausea/vomiting rates, opioid doses administered, length of stay and total net cost. METHODS The authors retrospectively reviewed the charts of all patients who underwent 1- or 2-level TLIF surgery by a single surgeon at a single institution from 2015-2017. Costs were included in analysis if they were: 1) non-fixed; 2) incurred in the OR; and 3) directly related to patient care. All cost data represents net costs, and was obtained from the hospital revenue cycle team. RESULTS A total of 29 patients received SA and 46 received GA. Both groups were similar in terms of age, gender, BMI, number of levels operated upon, preoperative diagnosis and medical comorbidities. The SA group spent less time in the OR (163.86±9.02 vs 195.63±11.27 min, p<0.05), PACU (82.00±7.17 vs 102.98±8.46 min, p<0.05), and under anesthesia (175.03±9.31 vs 204.98±10.15 min, p<0.05) than the GA group. Post-surgery OR time was significantly less with SA than with GA (6.00±1.09 vs 17.26±3.05 min, p<0.05); however, pre-surgery OR time was similar between groups. The SA group also experienced less maximum postoperative pain (3.31±1.41 out of 10 vs 5.96±0.84/10, p<0.05) and required less opioid analgesics (2.38±1.37 vs 5.39±0.84 doses, p<0.05). Both groups experienced similar nausea or vomiting rates and adverse events postoperatively. Net operative cost was found to be $812.31 (5.6%) less with SA than with GA, although this difference was not significant (p=0.225). CONCLUSIONS To our knowledge, SA is almost never used in lumbar fusion, and a cost-effectiveness comparison with GA has not been recorded. In this retrospective study, we demonstrate that the use of SA in lumbar fusion surgery leads to significantly shorter operative and recovery times, less postoperative pain and opioid usage, and slight cost savings over GA. Thus, we conclude that this anesthetic modality represents a safe and cost-effective alternative to GA in lumbar fusion. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs. Spinal anesthesia (SA) has been shown in several studies to be a viable alternative to general anesthesia (GA) in laminectomies, discectomies and microdiscectomies. However, the use of SA in spinal fusion surgery has been very scarcely documented in the current literature. Here we present a comparison of SA to GA in lumbar fusion surgery in terms of perioperative outcomes and cost. The objective of this study was to compare the cost and outcomes of SA and GA in minimally invasive transforaminal lumbar interbody fusion (TLIF) to demonstrate their relative cost-effectiveness. Patients undergoing minimally invasive TLIF were included in the study. Patients were stratified into two groups based on anesthetic modality: general anesthesia or spinal anesthesia. The setting of the study was a suburban, tertiary-care level university-affiliated hospital. A total of 75 patients underwent minimally invasive TLIF surgery, 36 males and 39 females with an age range of 20 to 87 years old. The main diagnoses for these patients were spondylolisthesis (58 patients) and spinal stenosis (57 patients), while degenerative disc disease (5) and herniated discs (3) were less commonly seen, with many patients having multiple diagnoses. The authors recorded patient demographic information, BMI, diagnosis, comorbidities, levels operated on, total OR time, total surgery time (incision to closure), time under anesthesia, post-anesthesia care unit (PACU) time, pain scores, adverse events, nausea/vomiting rates, opioid doses administered, length of stay and total net cost. The authors retrospectively reviewed the charts of all patients who underwent 1- or 2-level TLIF surgery by a single surgeon at a single institution from 2015-2017. Costs were included in analysis if they were: 1) non-fixed; 2) incurred in the OR; and 3) directly related to patient care. All cost data represents net costs, and was obtained from the hospital revenue cycle team. A total of 29 patients received SA and 46 received GA. Both groups were similar in terms of age, gender, BMI, number of levels operated upon, preoperative diagnosis and medical comorbidities. The SA group spent less time in the OR (163.86±9.02 vs 195.63±11.27 min, p<0.05), PACU (82.00±7.17 vs 102.98±8.46 min, p<0.05), and under anesthesia (175.03±9.31 vs 204.98±10.15 min, p<0.05) than the GA group. Post-surgery OR time was significantly less with SA than with GA (6.00±1.09 vs 17.26±3.05 min, p<0.05); however, pre-surgery OR time was similar between groups. The SA group also experienced less maximum postoperative pain (3.31±1.41 out of 10 vs 5.96±0.84/10, p<0.05) and required less opioid analgesics (2.38±1.37 vs 5.39±0.84 doses, p<0.05). Both groups experienced similar nausea or vomiting rates and adverse events postoperatively. Net operative cost was found to be $812.31 (5.6%) less with SA than with GA, although this difference was not significant (p=0.225). To our knowledge, SA is almost never used in lumbar fusion, and a cost-effectiveness comparison with GA has not been recorded. In this retrospective study, we demonstrate that the use of SA in lumbar fusion surgery leads to significantly shorter operative and recovery times, less postoperative pain and opioid usage, and slight cost savings over GA. Thus, we conclude that this anesthetic modality represents a safe and cost-effective alternative to GA in lumbar fusion.