Recent advances in anaesthetic and surgical practice have allowed an increasing number of patients to benefit from ambulatory surgery. This type of practice offers advantages for patients, healthcare providers, third-party providers and even hospitals . A variety of drugs and techniques have been introduced into ambulatory anaesthesia. The technique, as well as the drugs used, may hasten or delay home discharge [2-5]. The introduction of more rapid and shorter-acting anaesthetics and opioid analgesics can optimize intraoperative surgical conditions while providing a rapid recovery. Propofol is the hypnotic agent of choice for outpatient anaesthesia. It gives rapid emergence and a very low incidence of postoperative side-effects, e.g. nausea and vomiting, especially when combined with the ultrashort-acting opioid analgesic, remifentanil .
On the other hand, regional anaesthesia offers many advantages for ambulatory patients and spinal anaesthesia is the simplest and most reliable regional anaesthetic technique. In addition to limiting the anaesthetized area to the surgical site, the common side-effects of general anaesthesia (nausea, vomiting, drowsiness) are reduced, the risks of aspiration pneumonitis and the side-effects of tracheal intubation are minimized, and improved analgesia is provided in the postoperative period . Lidocaine has been the local anaesthetic of choice for spinal anaesthesia in the ambulatory setting because of its short duration of action. However, its use has been questioned for spinal anaesthesia because of the frequency of transient neurological symptoms; this problem occurs approximately 20% in the ambulatory setting [8-10]. Recent studies showed that the longer acting analgesic bupivacaine can be adapted to the ambulatory setting by using a smaller dose combined with the potent opioid fentanyl [11,12].
Our hypothesis was that low-dose intrathecal bupivacaine, in combination with fentanyl, was as good as total intravenous anaesthesia (TIVA) with propofol with respect to recovery and side-effects. Therefore, this study was designed to evaluate the recovery times, side-effects and patient satisfaction with two anaesthetic techniques, spinal anaesthesia and TIVA, in outpatients undergoing varicocele surgery.
The protocol was approved by our Hospital Ethics Committee and all patients gave written informed consent. Forty ASA I-II patients (18-65 yr) undergoing minor surgery for varicocele were enrolled. Patients with a medical contraindication to any of the two anaesthetic techniques (allergy, bleeding disorders, localized infection, or neurological disease) were excluded from the study. The unpremedicated patients were randomly assigned to be anaesthetized using one of two techniques:
• Group I: Spinal anaesthesia with hyperbaric bupivacaine and fentanyl.
• Group II: TIVA with propofol and remifentanil by continuous infusion and the placement of a laryngeal mask.
All patients were monitored with an automated blood pressure device, pulse oximetry, and an electrocardiogram (Critical Care 1100®; Criticare Systems, Inc., Milwaukee, WI, USA). Systolic (SBP) and diastolic (DBP) blood pressures and heart rate (HR) were recorded before induction of anaesthesia and every 5 min intraoperatively. Isolyte-S solution (crystalloid solution containing sodium and potassium chloride) 7 mL kg−1 was infused before induction.
Patients in Group Spinal (n = 20) had spinal anaesthesia administered using a midline approach with a 26-G atraumatic spinal needle (Atraucan®; Braun, Germany) at the level of the L2-3 or L3-4 intervertebral space with the patient in the sitting position. The subarachnoid injection contained hyperbaric bupivacaine 0.5% 5 mg and fentanyl 25 μg. Patients were placed in the supine position after completion of the block. The extent of the block was assessed by using pinprick and a modified Bromage scale (where 0 = full flexion of knees and feet; 1 = just able to flex knees, full flexion of feet; 2 = unable to flex knees, but some flexion of feet possible; and 3 = unable to move legs or feet) . Oxygen was administered via a facemask if SPO2 was <90%. Boluses (5 mg) of intravenous (i.v.) ephedrine were given as needed to treat hypotension (SBP < 90 mmHg) whereas bradycardia (HR < 50 beats min−1) was treated with i.v. atropine 0.5 mg. Any patients who failed to achieve adequate surgical or anaesthetic conditions were given general anaesthesia using propofol and remifentanil infusions.
Patients in Group TIVA (n = 20) received TIVA with a continuous infusion of propofol and remifentanil and the placement of a laryngeal mask. After atropine 0.5 mg i.v., patients received a remifentanil bolus of 1 μg kg−1 i.v., followed by an infusion of 0.5 μg kg−1 min−1 via an i.v. cannula in the basilic vein. The induction dose of propofol was then given at 2 mg kg−1 i.v., followed by an infusion at 9 mg kg−1 h−1 via a second cannula. A laryngeal mask was inserted. Ventilation of the lungs with an air/oxygen mixture was set to maintain PETCO2 between 4.8 and 5.3 kPa for the duration of the surgery. A diclofenac suppository 100 mg was inserted before the commencement of surgery. Five minutes after the skin incision, the infusion rates were decreased (remifentanil to 0.25 μg kg−1 min−1 and propofol to 6 mg kg−1 h−1). Patients were observed for depth of anaesthesia throughout surgery. Light anaesthesia was assumed from the observation of haemodynamic (SBP > 15 mmHg above preoperative baseline for >1 min or HR > 90 beats min−1 for >1 min), somatic (movement, eye opening or grimacing) or autonomic (lacrimation, sweating) changes . Light anaesthesia symptoms were treated by administering a bolus of remifentanil (0.5 μg kg−1), followed by a 50% increase in the infusion rate (from 0.25 μg kg−1 min−1 to 0.375 μg kg−1). Further symptoms were treated with rescue propofol boluses (up to 20 mg, twice). If two propofol boluses were unsuccessful, then an additional 20 mg bolus was given, and the propofol infusion rate was increased. Deep anaesthesia indicators were defined as SBP < 80 mmHg or HR < 40 beats min−1 for >1 min. Hypotension was treated with i.v. fluids and 50% decrements in the infusion rate of remifentanil. Vasopressor drugs were administered if a decrease in the opioid did not increase arterial pressure. Bradycardia was treated with anticholinergic drugs . At the end of the surgery, remifentanil and propofol infusions were discontinued in Group TIVA.
Patients were evaluated with respect to the return of normal sensation, muscle strength and proprioception, and recovery times in Group Spinal. Symptoms and signs were recorded from the end of surgery to ambulation, micturition and home readiness (meeting all discharge criteria). Recovery times in Group TIVA were recorded from the discontinuation of the anaesthetic drugs (propofol and remifentanil) to awakening, ambulation and home readiness. The recovery time, from the injection of the spinal anaesthetic, in Group Spinal was also noted. Discharge criteria included mental alertness, stable vital signs, absence of nausea, control of pain, ability to ambulate and, following spinal anaesthesia, spontaneous voiding . During the postoperative period, patients were observed for adverse events including pain and nausea or vomiting. The postoperative pain and nausea scores were assessed in the postoperative care unit by a nurse blinded to the study group. If the visual analogue scale (VAS) (where 0 = no pain and 10 = worst imaginable pain) was >4, patients were given diclofenac sodium 50 mg intramuscularly. Similarly, metoclopramide was given for nausea scores >4 (VAS, where 0 = no nausea and 10 = worst imaginable nausea). Recovery events and home readiness were assessed at 15 min intervals. Specific side-effects and patient satisfaction (with a three-point scoring system, where 1 = poor, 2 = good and 3 = excellent)  were evaluated by follow-up telephone call 24 h after surgery.
Statistical analyses were performed using the unpaired t-test for patient characteristics and recovery time. The χ2- or Fisher's exact tests were used for side-effects and patient satisfaction comparing the two groups. P < 0.05 was considered as statistically significant.
None of the patients had any medical contraindication to the anaesthetic techniques and all 40 patients who were enrolled completed the study. The groups were comparable with respect to patient characteristics and duration of surgery. The times taken for the patients to be ready for surgery following their arrival in the operating room were longer in Group Spinal than in Group TIVA (P < 0.05) (Table 1). There were no major surgical or anaesthetic complications. Anaesthesia was satisfactory at the time of incision in all patients. Only one patient in Group Spinal required treatment for hypotension and bradycardia. Times to ambulation were similar for both groups. Voiding of the bladder was required before discharge after spinal anaesthesia and the time to home readiness was longer in Group Spinal (P < 0.05) (Table 2). Three patients had a motor block of grade 2, whereas the remaining 17 patients had a grade 1 motor block in Group Spinal. The recovery times from the injection of the spinal anaesthetic in Group Spinal were 116.4 ± 39.7 min for the time to ambulate, 187.7 ± 37.4 min for the time to void and 195.8 ± 36.1 min for the time to home readiness. In Group Spinal, two patients reported mild pruritus and one patient mild postdural puncture headache (no associated symptoms, slight restriction of physical activity), which was controlled with oral analgesics. In Group TIVA, two patients reported nausea but did not need antiemetics. More patients required postoperative analgesia therapy in Group TIVA (P < 0.05) (Table 3). At the follow-up telephone call to home 24 h after surgery, five patients in Group Spinal and 18 patients in Group TIVA reported pain (P < 0.05). Acetaminophen (paracetamol) 500 mg four to six times a day was provided for use to relieve pain in these patients. No patients in the spinal anaesthesia group reported any back pain radiating to the legs (transient neurological symptoms). The patient who experienced headache in Group Spinal graded the anaesthesia as good. Six patients in Group TIVA reported that they would not choose the same anaesthesia technique again because of the pain experienced postoperation, and patient satisfaction was higher in Group Spinal compared with Group TIVA (P < 0.05) (Table 3).
We assessed recovery profiles, side-effects and patient satisfaction of the two anaesthetic techniques, spinal anaesthesia and TIVA, for outpatient varicocele surgery in this study. Patients receiving TIVA with remifentanil had a shorter time to home readiness, but a higher incidence of postoperative pain. Although ambulation times were similar between the two groups, the requirement for voiding resulted in longer discharge times for the spinal anaesthesia group.
Insistence that patients receiving general anaesthesia must be able to micturate can lead to delays in discharge. There is evidence that patients not at high risk of urinary retention can be safely discharged before they have voided . None of our patients in Group TIVA had a problem with respect to micturition after discharge. On the other hand, the ability to micturate is a common discharge criterion that may delay patient discharge after spinal anaesthesia . Pavlin and colleagues  suggested that voiding before discharge appeared unnecessary in those patients at low risk (e.g. non-pelvic surgery, no history of urinary retention) of urinary retention. In another study, they showed that patients at high risk could be monitored and managed optimally by determination of their urine volume by bladder ultrasound and the need for catheterization . None of our patients required catheterization, and if the requirement to micturate had been eliminated as a discharge criteria, both groups would have had comparable times to home readiness. However, such practice necessitates a close follow-up of patients at home for early diagnosis and appropriate management of postoperative complications. In a study that investigated the effects of adding fentanyl 10 μg to bupivacaine 5 mg intrathecally for ambulatory knee arthroscopy, neither the time to micturition nor the time to discharge were prolonged by adding fentanyl . Further studies are needed to evaluate whether ambulatory patients receiving intrathecal local anaesthetics alone or in combination with opioids can be discharged safely before micturating.
Regional anaesthesia offers many advantages for the ambulatory patient and spinal anaesthesia is the simplest and most reliable regional technique . However, spinal anaesthesia demands careful attention to drug, dose and needle selection in order to provide appropriate conditions . The risk of significant postdural puncture headache has been reduced by the use of small-gauge, rounded-bevel needles . Only one patient reported mild postdural puncture headache, which was controlled with non-opioids given orally. Lidocaine has been a popular choice for ambulatory anaesthesia. However, a new adverse effect, transient neurological symptoms, was described in patients recovering from single-injection spinal anaesthesia with lidocaine. Factors that demonstrate a causative relationship with transient neurological symptoms are the choice of the local anaesthetic, the lithotomy position and outpatient surgery . These symptoms are not unique for lidocaine but are also known to occur with other local anaesthetics. However, this adverse effect is mostly associated with lidocaine and mepivacaine, which are linked with much higher incidences than bupivacaine and prilocaine [17-20]. Although there have been published reports of transient neurological symptoms associated with the use of the hyperbaric solution, bupivacaine seems a local anaesthetic with a very low incidence of problems [17-19]. Recovery after spinal anaesthesia can be improved by decreasing the dose of bupivacaine and adding a potent opioid analgesic, e.g. fentanyl. On this basis, we used the lowest bupivacaine dose in combination with fentanyl, which had been reported by Kuusniemi and colleagues  for urological surgery of short duration. This combination was not associated with failed blocks and resulted in high patient satisfaction. Neither are hyperosmolarity, baricity or the addition of glucose contributing factors for transient neurological symptoms . Previous studies have compared the densities of intrathecal local anaesthetics, opioids and combinations, measured at 37°C, and accordingly the combination of hyperbaric bupivacaine 5 mg and fentanyl 25 μg that we used for spinal anaesthesia is still a hyperbaric one [23,24]. We considered the use of low-dose bupivacaine instead of lidocaine for outpatient surgery and did not observe transient neurological symptoms associated with hyperbaric bupivacaine 0.5%.
Numerous i.v. anaesthetics and combinations of anaesthetics have been used in TIVA techniques for ambulatory anaesthesia; propofol is now the induction agent of choice. Remifentanil has unique characteristics with a rapid onset and rapid offset of effect, regardless of the duration of its administration . We chose the newer short-acting anaesthetics and analgesics for Group TIVA. The infusion rates, as well as the bolus doses of remifentanil and propofol, we used were based on effective anaesthesia in a previous study . By using an laryngeal mask, we avoided muscle relaxants and 'reversal' agents. With the above-mentioned technique, our patients receiving general anaesthesia (TIVA) had a shorter time to home readiness compared with the spinal anaesthesia group, albeit that this was decided by the requirement for satisfactory micturition before discharge.
Postoperative pain is one of the most frequent postoperative adverse events and preoperative use of non-steroidal anti-inflammatory drugs may considerably decrease postoperative pain [13,26]. However, the preoperative administration of a non-steroidal anti-inflammatory drug was ineffective in controlling postoperative pain and 15 patients (75%) had pain scores necessitating rescue analgesia. Our findings of early postoperative pain are in accordance with those of Philip and colleagues  who found an 87% incidence rate of demand for analgesia when TIVA with remifentanil was used. The main reasons for dissatisfaction with ambulatory anaesthesia are intra- and postoperative adverse events. Moreover, inadequate pain control postoperation contributes to increasing patient dissatisfaction . Immediate postoperative pain treatment was required by more patients in Group TIVA compared with Group Spinal; six patients in Group TIVA reported they would not choose the same anaesthesia technique again because of the pain they experienced postoperation. The use of local anaesthesia applied by the surgeon or performing iliohypogastric nerve block  in combination with preoperative non-steroidal anti-inflammatory drugs for postoperative analgesia could have improved the ratings for general anaesthesia without delaying discharge in our study. Thus, multimodal pain control combining intraoperative opioids and local anaesthesia as well as non-steroidal anti-inflammatory drugs should be planned beforehand to take account of the short duration of action of remifentanil for patients having TIVA with remifentanil to increase patient satisfaction.
A major limitation of our study was that it was impossible to perform this study in a blinded fashion because of the nature of the anaesthetics as in previous studies . However, recovery and discharge times were collected by an observer every 15 min using standard, objective recovery criteria, and postoperative side-effects were assessed by an independent observer in the postoperative care unit.
There are several studies where spinal and general anaesthesia are compared in ambulatory knee arthroscopy [2,3,5]. Dahl and colleagues  showed that spinal anaesthesia with lidocaine 75-100 mg provided comparable discharge times to general anaesthesia with propofol. However, propofol anaesthesia was associated with more postoperative pain and a higher cost of drugs and disposables. A comparison of spinal anaesthesia using procaine, epidural block using 2-chloroprocaine and general anaesthesia with propofol showed that spinal anaesthesia was associated with the longest discharge and increased side-effects, e.g. pruritus . When spinal anaesthesia with lidocaine 50 mg and general anaesthesia (propofol and fentanyl for induction, isoflurane for maintenance) were compared, there was no difference in discharge times, although general anaesthesia was associated with nausea, pain, drowsiness and sore throat whereas spinal anaesthesia caused more backache . The limitation of this study was the use of isoflurane, since the use of a shorter-acting inhalational agent could have resulted in faster recovery times. The above-mentioned studies show that the choice of technique affects the recovery profile, incidence of side-effects and patient comfort after the same type of surgery.
It should also be noted that patients' choice is an important determinant when choosing the anaesthesia technique in the ambulatory setting. All of our patients accepted randomization, but some patients may have had a strong preference for regional or general anaesthesia. The type of surgery can also have an effect on patients' choice, since it has been shown that some patients undergoing knee arthroscopy refused randomization for general and regional anaesthesia. The majority of those patients preferred being awake, observing the procedure on a video screen .
In conclusion, we performed a prospective, randomized comparison of general and spinal anaesthesia for outpatient urological surgery. The recovery of patients was significantly shorter after TIVA with remifentanil compared with spinal anaesthesia with low-dose bupivacaine and fentanyl. However, multimodal pain control, including local anaesthetic infiltration, must be planned beforehand for patients having TIVA with remifentanil.
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