INTRODUCTION
Surgical techniques with endoscopic approaches for the treatment of lumbar disc herniation have been developed to reduce the length of hospitalization and to allow a rapid recovery with shorter length of stay in the postanesthesia care unit (PACU).
The choice of a regional anesthetic (epidural, intradural) is important for reducing complications during and after surgery and can affect patient recovery and comfort.
Studies have reported that intradural anesthesia (IA) may be more reliable than general anesthesia and although IA is the most frequently used method during regional anesthesia for lumbar endoscopic approach only few studies have compared epidural or IA in intraoperative and postoperative period.
MATERIALS AND METHODS
Permission was granted by the San Rafael Hospital Ethics Committee prior to retrospectively screening a total of 66 lumbar microdiscectomies (LMDs) under IA (n=21) or epidural anesthesia (EA) (n=45).
All patients provided written consent for the surgical procedure and anesthetic method. Patients with radicular pain or neurological deficits linked to disc compression as identified by magnetic resonance imaging.
Exclusion criteria included patients with contraindications to IA (international normalized ratio 1.5, platelets < 75,000, use of anticoagulant drugs).
All patients fasted for at least 6 hours before the procedure. After arrival in the operating room, a 20G peripheral intravenous catheter was inserted. Standard monitoring was used throughout the procedure, including noninvasive arterial blood pressure, electrocardiogram, and pulse oximetry. Decrease in systolic arterial blood pressure > 80 mmHg and bradycardia (heart rate < 50 beats/min) was treated with ephedrine.
Patients were recorded for age, sex, weight (body mass index, BMI), previous lumbar surgery, surgical endoscopy technique, comorbidities (diabetes, hypertension, obstructive sleep apnea [OSA]), American Society of Anesthesiologist (ASA) physical status (PS) classification, preoperative analgesic drugs, visual analogue scales (VAS) in radicular pain, operated disc levels, length of anesthesia technique and length of surgery, need of vasopressors (ephedrine), discomfort during surgery and need to convert to general anesthesia. In the postoperative period, the following was recorded: duration of the motor block, time to get up, time to ambulation, VAS in radicular pain, the need for urinary catheterization, and length of PACU stay. Only patients who underwent outpatient surgery have been analyzed (length of hospital stay < 12 hours).
1. Anesthesia Procedure
In the operating room, EA was administered in the sitting position under aseptic conditions at one level above the operation field. After local anesthesia with subcutaneous 2% mepivacaine, an 18-gauge Tuohy needle was inserted into the epidural space using the loss of resistance method and a 15 mL 0.5% bupivacaine was administered. Based on our experience, there were fewer technical difficulties in identifying the epidural space on the first attempt with patients in the sitting position compared to the lateral position. In the lateral position, epidural blocks extended more cephalad than with the sitting position. The insertion time in the sitting position is significantly shorter than in the lateral position. However, the lateral decubitus position is better for avoiding vagal reflexes. Most anesthetists prefer to perform EA with the patient sitting, although in fearful or agitated patients, it is preferable to perform it in the lateral position.
IA was administered in decubitus lateral position, a 25G spinal needle was used for lumbar puncture and 3 mL 0.5% isobaric bupivacaine were administered. After the injection, the patients were placed in the most comfortable prone position, and they were sedated using 0.03-mg/kg midazolam and 3 L/min flow rate of oxygen through nasal cannula. Patients with discomfort during surgery were administered low doses of propofol or remifentanil.
Additionally, antibiotic prophylaxis was administered using 1 g of cefazolin before skin incision and 1 g every 8 hours postoperatively. Prednisone 8 mg intravenous (IV), paracetamol 1,000 mg IV and dexketoprofen 50 mg IV was administered in all patients.
2. Statistical Analyses
IBM SPSS Statistics ver. 21.0 (IBM Co., Armonk, NY, USA) was used for the statistical analyses. Descriptive statistics for continuous variables are given as the mean±standard deviation and median (range) values. Comparisons between the groups were completed with Mann-Whitney tests and independent sample t-tests for continuous variables, and chi-square tests for categorical variables. A correlation analysis was also completed. Statistical significance was accepted at p<0.05.
RESULTS
A total of 45 LMD surgeries were performed under EA and 21 were performed under IA. There was no significant difference between the EA and IA patients in terms of sex, BMI, smoker, diabetes, hypertension, OSA, motor dysfunction, preoperative anti-inflammatory analgesics (NSAIDs), opioids or antiepileptics. (p> 0.05) (Table 1).
Twenty-seven of the operations performed under EA were 1 level and 18 were 2 levels. Six of the operations performed under IA were 1 level and 15 were 2 levels (p<0.05). Forty patients with EA were ASA PS classification grade I–II and 5 were ASA PS classification grade III. In the IA group, 20 patients were ASA PS classification grade I–II and 9 were ASA PS classification grade III (p<0.05) (Table 1). Comorbidities such as hypertension, OSA, urinary dysfunction and previous lumbar surgery were more frequent in IA group (p<0.05).
No patient needed to be converted to general anesthesia. Two patients with EA needed additional sedation due to some discomfort or slight pain. All patients with EA during surgery could mobilize their feet and legs if ordered, they did not have a complete motor block.
The time for performing the epidural or IA technique was similar. Eight patients with EA and 2 patients with IA required additional sedation with propofol and remifentanil due to slight pain and discomfort (p>0.05). Length of surgery was longer in patients with IA and more frequent use of vasopressors (p<0.05). In PACU minimal root pain in both groups (p>0.05). However, the need for urinary catheterization, duration of motor block, time to get up, time to ambulation and length of PACU stay was much higher in patients with IA (p<0.05).
Patients discharge in PACU after recovery of the motor block and had no adverse effects like shivering, nausea, vomiting or urinary retention.
There was no difference in length of hospital stay or patient satisfaction with different anesthetic techniques (p>0.05) (Table 2).
DISCUSSION
LMD is usually performed under general anesthesia but in recent years, IA and EA methods have been determined to be effective and reliable for lumbar disc surgeries with reduced complications linked to GA [1-8].
In our study, the anesthetist determined the appropriate anesthetic technique, opting between epidural and IA, based on the anticipated duration of the surgery. For surgeries expected to be longer in duration (particularly in patients with multiple comorbidities, hypertension, advanced age, previous lumbar surgeries, or multilevel herniations) IA was chosen due to its duration exceeding 3 hours. Conversely, single-dose EA was selected for surgeries anticipated to last less than 2 hours. This criterion explains why surgical time is shorter when EA is performed. Nevertheless, these factors did not influence the length of hospital stay (no statistical difference, p>0.05) in patients who received epidural or IA.
The need for vasopressor drugs is more frequent in IA than in EA; in our study it was much higher, probably due to the comorbidities of the patients who received IA [9-13].
Neurological examination can be easily completed in patients operated under EA as their superficial sensation and motor strength remain intact during surgery. A patient with IA needs hours to neurological recovery and, in spinal surgery, it is very important to perform an early assessment of the neurological status, as facilitated by EA [14,15].
Patient comfort during the intra and postoperative period was excellent. In the current study, although all patients received analgesia (NSAIDs and corticoids) in the operating room, patients with minimal root pain did not require analgesia in the PACU. The combination of intravenous analgesic and IA was very effective to keep the patient pain-free.
Our study compared duration of the motor block in PACU, time to get up, time to ambulation and time to discharge in PACU between epidural and IA. The study demonstrates that EA provides quick recovery from motor block and reduces time to get up, time to ambulation and time to discharge in PACU in comparison to IA. In other studies, with IA, the results were very similar to ours [16-18].
Patients who received IA were discharged in PACU after recovery of the motor block, but time to get up and time to ambulation were delayed until the patient was admitted on the hospital floor. However, all patients who received EA ambulated in the PACU.
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