Isobaric Spinal Anesthesia for Lumbar Disk Surgery

This is the authors' abstract. We don't add key points for this paper.

To the Editor: We agree with Jellish et al. [1] regarding the advantages of spinal versus general anesthesia for lumbar disk surgery, including primarily reduced postoperative pain and nausea and vomiting. These advantages are important for a smooth and pleasant recovery when this procedure is performed for outpatients. We write to report a technique slightly different from that described by Jellish et al., one that we feel may offer even more advantages. We use an isobaric local anesthetic solution, 0.5% bupivacaine 10 mg, for spinal anesthesia because the final dermatomal anesthetic level is not affected by patient position during and after injection of the spinal anesthetic [2]. This allows us to inject the spinal anesthetic with patients in the prone position after they have positioned themselves on the operating room table. This method requires less operating room time because the patient may be prepped and draped for surgery while the spinal anesthetic is setting up. Jellish et al. reported waiting "approximately 10 minutes" for their hyperbaric spinal anesthetic level to stabilize before turning patients prone and beginning the surgical prep. In addition to being more time-efficient, the incidence of hypotension and high spinals may be lower with an isobaric (versus hyperbaric) spinal technique because the highest spinal anesthetic level obtained is usually lower [3,4]. The intraoperative advantages (more reliable block and stable blood pressure) of isobaric versus hyperbaric bupivacaine spinal anesthesia has been described, but postoperative data were not reported [5]. We note that Jellish et al. specifically omit adding an opioid to the spinal anesthetic solution to avoid urinary retention. We usually add fentanyl 25 micro g to our spinal anesthetic solution to provide additional intraoperative and postoperative analgesia and have not found opioid side effects to be a problem. (Table 1) lists some retrospective results for the first seven patients who underwent single-level disk surgery under spinal anesthesia and seven demographically similar patients who had general anesthesia at our institution. We feel that the differences will become even greater as we gain more experience.Table 1: Isobaric Spinal Anesthesia Versus General AnesthesiaThis technique has allowed almost all of our patients to be discharged on the day of surgery. We feel that isobaric spinal anesthesia offers significant benefits compared with general anesthesia for single-level lumbar disk surgery and has at least theoretical advantages compared with hyperbaric spinal anesthesia. George W. Rung, MD Department of Anesthesia; University Hospital; Milton S. Hershey Medical Center; Pennsylvania State University College of Medicine; Hershey, PA 17033 Dan Williams, DO Department of Anesthesia; University Hospital; Milton S. Hershey Medical Center; Pennsylvania State University College of Medicine; Hershey, PA 17033 Daniel E. Gelb, MD Department of Orthopaedics and Rehabilitation; University Hospital; Milton S. Hershey Medical Center; Pennsylvania State University College of Medicine; Hershey, PA 17033 Mark Grubb, MD Department of Orthopaedics and Rehabilitation; University Hospital; Milton S.