Lumbar spine instrumented fusion surgery under spinal anaesthesia versus general anaesthesia-A retrospective study of 239 cases

Abstract

Objective

Conventionally spinal surgeries are done under general anaesthesia (GA). Plenty of literature is available on lumbar spine non-instrumented surgeries under spinal anaesthesia (SA) but handful of literature is there on lumbar spinal instrumented fusion surgeries under SA. We retrospectively analysed the data of 131 patients operated under SA and 108 patients under GA. Aim of the study was to evaluate the safety, advantages and disadvantages of doing lumbar spine instrumented fusion surgeries under SA.

In time of COVID-19 pandemic, aerosol generating procedure like intubation, can be avoided if lumbar spine instrumented fusion surgeries are performed under SA.

Methods

239 patients aged between 20 and 79 years operated from January 2014 to December 2019 were included in this study. Indications for surgery were lumbar canal stenosis, degenerative or lytic spondylolisthesis. They underwent L4-L5 or L5-S1 fusion surgeries either TLIF or pedicle screw fixation postero lateral fusion (PLF) and decompression. Out of 239 patients,131 were operated under SA and 108 patients under GA. Heart rate, mean arterial pressure (MAP), blood loss, operating room time, post-op pain relief and need of analgesics, cost of surgery and anaesthesia related complications were analysed.

Results

The study found significantly less blood loss (p<.05), less OR time, better post-op analgesia and lesser incidence of nausea and vomiting in SA (8.4%) than GA (29.6%). We observed average 10% cost reduction in SA. This study did not find any prone position related complication in regional anaesthesia but one transient brachial plexus palsy and one post-op shoulder pain in GA group.

Conclusion

SA is a safe alternative to GA for lumbar spine instrumented fusion surgery with significant less blood loss, OR time, better post-op analgesia, average 10% overall cost reduction and no reported prone-position related complications.

Introduction

General anaesthesia is conventionally and widely used across the globe for spinal surgery. In last decade few centres have tried spinal anaesthesia for lumbar spine surgeries with encouraging results.1, 2, 3, 4, 5, 6, 7 Majority of all the studies of SA on lumbar spine surgeries are on non-instrumented simple surgeries like laminectomy and lumbar discectomy. There is paucity of research on lumbar spine instrumented fusion surgeries in prone position under spinal anaesthesia.

Studies have shown surgery under epidural anaesthesia is associated with less blood loss compared with general anaesthesia.⁸ We also observed decreased per-operative blood loss in SA group in comparison to GA group. Post operative complications like post op hypoxia, thrombo-embolic episodes, cardiac events, respiratory problems, incidence of nausea -vomiting are less in case of regional anaesthesia.9, 10, 11, 12

SA offers better analgesia in post-op period than GA with lesser analgesic requirement in first 24 h.⁵

Additional benefit of SA is awake patient can position themselves according to their comfort and chance of brachial plexus injury or eye injury due to prone positioning is almost nil.⁵

SA is safer anaesthesia for patients with lung, liver and kidney diseases which are not uncommon in older age group. In our experience patients who underwent lumbar spine surgery under SA had less adverse effect in comparison to GA.

Mac Lain et al.⁴ found higher surgeon and patient satisfaction in lumbar microdiscectomy patients when done under SA in ASA I patients.

Now in the time of Covid-19 pandemic it is advised to avoid tracheal intubation/GA to prevent aerosol generation¹³ and regional anaesthesia like SA is a better alternative wherever applicable.