P141. Awake spinal fusion: comparative outcome analysis of spinal anesthesia in lumbar fusion

Abstract

BACKGROUND CONTEXT Spinal anesthesia (SA) has been shown in several studies to be a viable alternative to general anesthesia (GA) in laminectomies and discectomies. However, very few spine surgeons have extended the use of SA to lumbar fusion surgery, and few studies have documented its use in the literature. The authors posit that SA may lead to lower postoperative pain than GA, and thus have implemented use of a novel thoracolumbar interfascial plane (TLIP) block for additional long-lasting analgesia. PURPOSE The purpose of this study was to evaluate the effectiveness of SA and SA+TLIP block in patient outcomes following spinal fusion surgery. STUDY DESIGN/SETTING Patients undergoing lumbar spine fusion surgery were included in this study. Patients were categorized based on anesthetic modality. The setting of the study was a suburban, tertiary-care level university-affiliated hospital. PATIENT SAMPLE A total of 111 patients, 53 males and 58 females, were included in the study, with an age range of 20 to 87 years old. Leading diagnoses were: spondylolisthesis (68 patients), stenosis (62 patients) and degenerative disc disease (5 patients). OUTCOME MEASURES The authors recorded patient demographic information, BMI, diagnosis, comorbidities, levels operated on, post-anesthesia care unit (PACU) time, pain scores, adverse events, opioid doses administered and length of stay. METHODS The authors retrospectively reviewed the charts of all 111 patients who underwent 1- or 2-level minimally invasive transforaminal lumbar interbody fusion (TLIF) surgery by a single surgeon, at a single institution, from 2015-2018. TLIP block consisted of injection of a long-acting local anesthetic agent in liposomal suspension into the fascial plane between the multifidus and longissimus muscles. Patients were placed into groups based on anesthetic modality: GA; SA; or SA+TLIP block. RESULTS A total of 29 patients received SA, 46 received GA and 36 received SA+TLIP block. All groups were similar in terms of age, gender, BMI, number of levels operated upon, preoperative diagnosis and ASA physical score. Both the SA and SA+TLIP groups experienced significantly lower max postoperative pain scores (3.31±1.65 out of 10 and 1.69±0.95/10, respectively) than the GA group (5.96±0.84/10, p<0.05). Additionally, the SA and SA+TLIP groups required fewer opioid doses in the PACU (2.38±1.76 and 1.28±0.69 doses) than the GA group (5.39±1.24 doses, p<0.05). Time spent in the PACU was significantly less for SA and SA+TLIP groups (82.0±8.69 and 74.1±8.09 min) than the GA group (102.9±8.45 min, p<0.001). Further, the SA+TLIP group spent fewer days in the hospital (0.74±0.44 days) compared with the GA group (1.30±0.32 days, p<0.01). The SA+TLIP group had lower initial, final, and max pain scores; required less opioid doses; spent less time in the PACU; and had a shorter length of stay than the SA group, although these results did not reach statistical significance. No significant difference in adverse events was observed among the three groups. CONCLUSIONS To our knowledge, the use of the preoperative TLIP block is a novel concept in spine surgery. In this study, we demonstrate that use of SA+TLIP in TLIF surgery can lead to less time spent in the PACU, lower pain scores, fewer opioid doses and can reduce average length of stay compared to GA. Addition of the TLIP block may lead to even lower pain and opioid usage over SA alone, though our sample size was not large enough to achieve significance. Thus, SA and SA+TLIP block appear to be viable and beneficial alternatives to GA for TLIF surgery. 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 and discectomies. However, very few spine surgeons have extended the use of SA to lumbar fusion surgery, and few studies have documented its use in the literature. The authors posit that SA may lead to lower postoperative pain than GA, and thus have implemented use of a novel thoracolumbar interfascial plane (TLIP) block for additional long-lasting analgesia. The purpose of this study was to evaluate the effectiveness of SA and SA+TLIP block in patient outcomes following spinal fusion surgery. Patients undergoing lumbar spine fusion surgery were included in this study. Patients were categorized based on anesthetic modality. The setting of the study was a suburban, tertiary-care level university-affiliated hospital. A total of 111 patients, 53 males and 58 females, were included in the study, with an age range of 20 to 87 years old. Leading diagnoses were: spondylolisthesis (68 patients), stenosis (62 patients) and degenerative disc disease (5 patients). The authors recorded patient demographic information, BMI, diagnosis, comorbidities, levels operated on, post-anesthesia care unit (PACU) time, pain scores, adverse events, opioid doses administered and length of stay. The authors retrospectively reviewed the charts of all 111 patients who underwent 1- or 2-level minimally invasive transforaminal lumbar interbody fusion (TLIF) surgery by a single surgeon, at a single institution, from 2015-2018. TLIP block consisted of injection of a long-acting local anesthetic agent in liposomal suspension into the fascial plane between the multifidus and longissimus muscles. Patients were placed into groups based on anesthetic modality: GA; SA; or SA+TLIP block. A total of 29 patients received SA, 46 received GA and 36 received SA+TLIP block. All groups were similar in terms of age, gender, BMI, number of levels operated upon, preoperative diagnosis and ASA physical score. Both the SA and SA+TLIP groups experienced significantly lower max postoperative pain scores (3.31±1.65 out of 10 and 1.69±0.95/10, respectively) than the GA group (5.96±0.84/10, p<0.05). Additionally, the SA and SA+TLIP groups required fewer opioid doses in the PACU (2.38±1.76 and 1.28±0.69 doses) than the GA group (5.39±1.24 doses, p<0.05). Time spent in the PACU was significantly less for SA and SA+TLIP groups (82.0±8.69 and 74.1±8.09 min) than the GA group (102.9±8.45 min, p<0.001). Further, the SA+TLIP group spent fewer days in the hospital (0.74±0.44 days) compared with the GA group (1.30±0.32 days, p<0.01). The SA+TLIP group had lower initial, final, and max pain scores; required less opioid doses; spent less time in the PACU; and had a shorter length of stay than the SA group, although these results did not reach statistical significance. No significant difference in adverse events was observed among the three groups. To our knowledge, the use of the preoperative TLIP block is a novel concept in spine surgery. In this study, we demonstrate that use of SA+TLIP in TLIF surgery can lead to less time spent in the PACU, lower pain scores, fewer opioid doses and can reduce average length of stay compared to GA. Addition of the TLIP block may lead to even lower pain and opioid usage over SA alone, though our sample size was not large enough to achieve significance. Thus, SA and SA+TLIP block appear to be viable and beneficial alternatives to GA for TLIF surgery.