Ambulatory surgery is an increasing service in all hospitals, all over the world.
In the USA, up to 75% of all operations are performed as day case surgery. We too, as anesthesiologists, have a great impact on this service as we can provide general or regional anesthesia techniques to our patients.
It has been demonstrated that regional anesthesia provides a better outcome for patients during operations and in the postoperative phase with lower morbidity and mortality figures than general anesthesia. Nowadays, many patients want to be awake during their operation, being in full control over their own body.
Types of loco-regional anesthesia which can be used during ambulatory surgery:

Patient advantages when loco-regional anesthesia techniques are used during ambulatory surgery:

Surgeon and hospital advantages when loco-regional anesthesia techniques are used during ambulatory surgery:

Disadvantages of the use of loco-regional anesthesia during ambulatory surgery:

Requirements of a good Regional Anesthesia Service for Outpatient Surgery:

The success of regional anesthesia depends on a well- informed patient and operating team, a good organization, adequate well-trained personnel, a dedicated and well equipped block room corner separate from the OR, a good knowledge of anatomy, an adequate position of the patient during the block insertion, adequate care and aftercare of the patient. The patient can, depending on his preference, be given the possibility to listen to music, see his operation on video,…
Of course a knowledgeable anaesthesiologist, capable of performing regional anesthesia techniques is crucial. Monitoring should always be applied and patients should be checked postoperatively for side effects and pain experience.
The worst case scenario is that the regional anesthesia block does not result in what you, the patient, or the team expects from the block: e.g. the patient has to be given general anesthesia, supplemental sedation or analgesics, the patient has to stay overnight, the patient has to be readmitted for raisons of severe pain or postoperative nausea and vomiting, bleeding problems,…
Using more regional anesthesia blocks also safes on anesthesia costs. It has been demonstrated that the anesthesia technique used is the most important determinant of discharge time. The operating time is now pure surgical time, which means that there is no time needed for induction or reve rsal of anesthesia if regional anesthesia techniques are used.
Central neural blocks are used frequently, but both epidural and spinal techniques have disadvantages. Peripheral nerve blocks are more and more used. Newer blocks as the Pippa block, the vertical infraclavicular block, the poplitea block,… are a welcome addition in the armamentarium of the modern anesthesiologists. They often provide excellent and long-lasting pain relief, which allows a faster recovery and an early discharge of the patient. Rarely complications are seen and the blocks are well-tolerated by the patients and easy to perform, providing excellent analgesia. This even allows effective physiotherapy to be given at an earlier stage, again contributing to a faster recovery from the operation.
Peripheral nerve blocks can also be used when central blocks do not result in 100% satisfactory blocks. It is essential that anesthesiologists master these blocks, including peripheral nerve blocks (e.g. penile block, selective blocks of the nn. medianus, ulnaris, radialis, ankle block,…). The latter are often sufficient enough on their own to produce to result in adequate analgesia during the operating, avoiding the more central and plexus blocks.
Overall when the well-trained anesthesiologist provides the right block for the right indication in the right patient, with the right equipment, the outcome should be excellent. Therefore the question arises: Can we afford NOT to use regional anesthesia for outpatient surgery?

The concept of continuous spinal anaesthesia (CSA) was first described by the British surgeon Dean in 1907 (1) who left the spinal needle in place during an operation. In 1939, Lemmon (2) introduced the malleable needle and the split mattress technique to overcome the problems of needle trauma and breakage. Tuohy (3) introduced the catheter technique - he used a no.4 ureteral catheter inserted through a 15 gauge needle. Throughout the following years, the fear of CSA resulting in high incidence rates of postdural puncture headache (PDPH) and neurological complications, along with the development of the epidural technique, discouraged the frequent use of CSA. Since the incidence of PDPH depending on cerebrospinal fluid loss is due to needle size and tip configuration (4), Hurley and Lambert introduced micro catheter systems in an effort to reduce frequency of PDPH associated with spinal anaesthesia (5). Thus, CSA technique became suitable also for the use in younger patients without incurring an unacceptable risk of PDPH.
However, serious neurological complications such as cauda equina syndrome after CSA performed with microcatheters were described by Rigler et al. in 1991 (6); additional cases after CSA administered through microcatheters resulted in a safety alert of the Food and Drug Administration in 1992. Spinal micro catheters thinner than 24 gauge inteded for the use in CSA were banned from the US-market. Furthermore, manufacturers of local anaesthetics declared that their products were not indicated for the use with CSA. In all, approximately 12 cases of cauda equina syndrome after CSA with microcatheters have been reported (7).
This reinforced the misconception that CSA was a dangerous technique. However, with experiences gained from more than 3000 patients in the course of five years, CSA appears in a totally different light to me - namely as an effective and safe technique when performed correctly. Therefore, I give a brief update on the present status and possible future directions for CSA.
CSA offers the attractive possibility of extending the block during surgery when needed. It provides an easy technique to reach an adequate level and duration of anaesthesia with small intermittent doses of local anaesthetic, which also minimizes the risk of possible cardiovascular and respiratory disturbances.
Several studies have shown that haemodynamic stability is greater with CSA than with continuous epidural anaesthesia (CEA). For example, Sutter et al. (8) retrospectively compared more than 700 patients who underwent lower limb orthopaedic surgery either with CSA or with CEA. Although the patients in the CSA group were at a higher anaesthetic risk, the incidence of failures was lower and fewer patients showed a decrease in the mean arterial pressure. CSA thus was more reliable and provided better cardiovascular stability for elderly and high-risk patients.
Such results can be attributed to the fact that CSA allows administration of small incremental doses of local anaesthetics at different concentrations and baricity according to the need of the individual patient, whatever surgical procedure and position are required. The better cardiovascular stability observed in CSA patients seems to be a result of the more easily controlled sympathetic blockade (9).
Other advantages of CSA compared with CEA are a more complete muscular blockade and smaller dosage of local anaesthetic to obtain adequate anaesthesia, without any risks of systemic toxic effects due to absorption. The large dose of local anaesthetics administered with epidural anaesthesia means that elderly patients are at greater risk of intoxication because of their reduced clearance for local anaesthetics and their reduced cardiac output and liver blood flow (10). Since the elderly population is increasing, and since these patients often have concomitant medical problems and reduced physiologic adaptation capacities, CSA might be the anaesthetic technique of choice for such patients, especially when haemodynamic stability is critical (11, 12, 13, 14).
By contrast to the question of intraoperative anaesthesia with CSA, there are only few studies published on the use of spinal catheters for postoperative analgesia (15, 16, 17).
There is general agreement about the major goals of postoperative pain treatment such as minimizing the patient’s discomfort, facilitating the recovery process and avoiding side effects. Nevertheless, unrelieved postoperative pain is still reported to be a rather common clinical problem (18, 19). There is increasing evidence in the literature that especially for major orthopaedic surgery techniques using regional anaesthesia provide a pronounced inhibitory effect on the stress response and have beneficial effects on outcome variables (20). Finally, the fact that morbidity and hospital stay decrease with the use of such techniques implies economic aspects that should not be underrated nowadays (21, 22).
Postoperative pain relief using CSA was first described by Ansbro et al. (23). Concerning the question whether to prefer CSA or CEA for postopertive pain control, Niemi et al. (24) randomized 55 patients who underwent hip arthroplasty under spinal anaesthesia to receive postoperative analgesia either using an intrathecal or an epidural catheter. Spinal catheter failures were found to present a significant disadvantage of CSA. However, Standl et al. (25) presented 100 patients undergoing lower limb orthopaedic surgery who received CSA using a 28 gauge catheter inserted through a 22 gauge needle and 0.25% bupivacaine titrated as bolus injections in the postoperative period. Their data suggest that CSA provides good postoperative analgesia, associated with a low incidence of complications and a high acceptance of CSA reported from the patients.
In our research group, we found in a randomized, prospective study with 102 patients that both techniques result in adequate postoperative pain relief (26). In both groups, the level of pain was gauged from verbal rating score and from a visual analogue scale. In the CSA-group 90.2% reported complete analgesia on the verbal rating score, but only 21.6% of the CEA-group did so. Throughout the study period of 72 postoperative hours, the visual analogue scores given by the CSA-group were significantly lower than those of the CEA-group. It can be concluded that CSA and CEA proved to be effective and safe, but CSA provided faster onset of pain relief, ensured better analgesia and produced more satisfied patients. As the incidence of side effects such as motor blockade, nausea and vomiting was comparable in both groups, CSA should be regarded as an attractive technique for a flexible postoperative pain therapy.
Asked about their main point of fear, most critics of CSA mention two complications:
neurological damage and cerebrospinal fluid infection.
Unfortunately, only few prospective studies have formally investigated the real incidence of neurological complications (27). That is why we tried in our research group to evaluate the frequency of permanent neurologic sequelae after CSA in a standardized pre- and postoperative investigation (28). A preoperative neurological status was gained from 150 patients who underwent hip arthroplasty with CSA technique, and the same neurological status was gained by the same anaesthetist ten days after surgery. At the occasion of this examination, no patient had noticed any remarkable differerence on his own; nevertheless, in four patients who suffered from Diabetes mellitus II a decrease of the quadriceps-femoris reflex was found. No differences in physical power were found and no cauda equina syndrome arose. All patients reported complete satisfaction with anaesthesia and postoperative shape and no serious complications were found - thus CSA should no longer be just condemned as a „risky technique", but more prospective clinical studies on this question are mandatory in the future.
In order to research on the risk of infection when performing CSA in the postoperative period, in 144 patients, who successfully underwent CSA for surgery, CSF was sampled both immediately after positioning and before removing the catheter (29). Leukocytes, proteins and glucose concentration were determined, meninigsm and infection parameters were compared preoperatively and by removal. The catheter was removed under aseptic conditions, the tip was cut and washed with saline. CSF, tip and saline were cultured to find microbiological contamination. In five cases bacteria were found in CSF, the catheter tip was contaminated in eight cases and saline in one case. Statistically significant positive correlation with the indwelling catheter time was found. Signs of local infection at the insertion side appeared in three cases with CSA lasting longer than 90 hours. However, no patient showed evidence of local or systemic infection with CSA for up to 200 hours. Taking into consideration that a meticulous technique of insertion and handling the catheter is mandatory, as well as a daily inspection of the insertion site, we conclude from our results that fear of infection should no longer lead to restrictions in the use of CSA in the postoperative period(, even when performed for 200 hours).
In conclusion, CSA is an established anaesthetic technique that has advantages over CEA especially in elderly or high-risk patients. Correctly used, CSA is an effective and safe technique - not only for intraoperative anaesthesia but also for an up-to-date postoperative pain treatment. Former doubts about its safety can be regarded as eliminated by clinical studies published over the last years that should encourage the more frequent use of this technique in the future.

References:
1. Dean HP. Discussion on the relative value of inhalational and injection methods of inducing anaesthesia. Br Med J 1907: 5: 869-877
2. Lemmon WT. A method for continuous spinal anaesthesia. Ann Surg 1940: 111: 141-144
3. Tuohy EB. Continuous spinal anaesthesia: Its usefulness and technique involved. Anesthesia 1944: 5: 142-148
4. Holst D, Möllmann M, Ebel C, Hausmann R, Wendt M. In vitro investigation of cerebrospinal fluid leakage after dural puncture with various spinal needles. Anesth Analg 1998: 87: 1331-1335
5. Hurley RJ, Lambert DH. Continuous spinal anaesthesia with a micro catheter technique: the experience in obstetrics and general surgery. Reg Anesth 1989: 14: 3-8
6. Rigler ML, Drasner K, Krejcie TC et al. Cauda equina syndrome after continuous spinal anaesthesia. Anesth Analg 1991: 72: 275-281
7. Denny NM, Selander DE. Continuous spinal anaesthesia. Br J Anaesth 1998: 81: 590-597
8. Sutter PA, Gamulin Z, Forster A. Comparison of continuous spinal and continuous epidural anaesthesia for lower limb surgery in elderly patients - A retrospective study. Anaesthesia 1989: 44: 47-50
9. Standl T, Eckert S, Rundshage I, Schulte am Esch J. A directional needle improves effectiveness and reduces complications of microcatheter continuous spinal anaesthesia. Can J Anaesth 1995: 42: 701-705
10.Greenblatt DJ, Sellers EM, Shader RI. Drug disposition in old age. N Engl J Med 1982: 306: 1081-8
11.Covert CR, Fox GS. Anaesthesia for hip surgery in the elderly. Can J Anaesth 1989: 36: 311-319
12.Carpenter RL, Caplan RA, Brown DL, et al. Incidence and risk factors for side effects of spinal anesthesia. Anesthesiology 1992: 76: 906-916
13.Favarel-Garrigues JF, Sztark F, Petitjean ME, Thicoipé M, et al. Hemodynamic Effects of spinal anesthesia in the elderly: Single dose versus titration through a catheter. Anesth Analg 1996: 82: 312-316
14.Holst D, Möllmann M, Karmann S, Wendt M. Kreislaufverhalten unter Spinalanästhesie. Anaesth 1997: 46: 38-42
15.Bachmann M, Laakso E, Niemi L, Rosenberg PH, et al. Intrathecal infusion of bupivacaine with or without morphine for postoperative analgesia after hip and knee arthroplasty. Br J Anaesth 1997: 78: 666-670
16.Niemi L, Pitkanen M, Dunkel P, Laakso E, Rosenberg PH. Evaluation of the usefulness of intrathecal bupivacaine infusion for analgesia after hip and knee arthroplasty. Br J Anaesth 1996: 77: 544-545
17.Burchett KR, Denny NM. Initial experience of continuous subarachnoid diamorphine infusion for postoperative pain relief. Reg Anesth 1991: 16: 253-256
18.Kehlet H. Postoperative pain relief - what is the issue? - Editorial. Br J Anaesth 1994: 72: 375-378
19.Dahl JB, Kehlet H. The value of pre-emptive analgesia in the treatment of postoperative pain. Br J Anaesth 1993: 70: 434-439
20.Kehlet H. General vs regional anaesthesia. In: Rogers M, Tinker J, Covino B, Longnecker DE, eds. Principals and Practice of Anesthesiology. St Louis: C.V. Mosby, 1993: 1218-1234
21.Mahoney OM, Noble PC, Davidson J, Tullos HS. The effect of continuous epidural analgesia on postoperative pain, rehabilitation and duration of hospitalization in total knee arthroplasty. Clin Orthop 1990: 260: 30-37
22.Schug SA. Continuous regional anaesthesia in comparison with intravenous opioid administration for routine postoperative pain control. Anaesth 1994: 49: 528-523
23.Ansbro FP, Latteri FS, Blundell AE et al. Prolonged spinal anaesthesia. Anesthesiology 1954: 15: 569-571
24.Niemi L, Pitkänen M, Tuominen M, Rosenberg P. Technical problems and side effects associated with continuous intrathecal or epidural post-operative analgesia in patients undergoing hip arthroplasty. Eur J Anaesth 1944: 11: 469-474
25.Standl T, Eckert S, Schulte am Esch J. Microcatheter continuous spinal anaesthesia in the post-operative period: a prospective study of its effectiveness and complications. Eur J Anaesth 1995: 12: 273-279
26.Möllmann M, Cord S, Holst D, Auf der Landwehr U. Continuous spinal anaesthesia or continuous epidural anaesthesia for postoperative pain control after hip replacement? Eur J Anaesth 1999: 16: 454-461
27.Horlocker TT, McGregor DG, Matsushige DK, et al. Neurologic Complications of 603 Consecutive Continuous Spinal Anesthetics Using Macrocatheter and Microcatheter Techniques. Anesth Analg 1997: 84: 1063-1070
28.Möllmann M, Cord S, Mayweg S, Frerker K. The Risk of Permanent Neurologic Sequelae after Continuous Spinal Anesthesia. Reg Anaesth Pain Med 1999 (Suppl 1): 24: 22
29.Santamaria M, Möllmann M, Röttger T, Auf der Landwehr U. Continuous spinal anaesthesia: is there a risk of infection? Br J Anaesth (Suppl 1) 1998: 80: 116