The beginning of epilepsy surgery in the English-speaking world was largely the result of the simultaneous establishments of abiding interests in the surgical treatment of epilepsy in Chicago and Montreal in the middle third of the twentieth century. The Montreal school (Montreal Neurological Institute, McGill University) initiated the use of local anesthesia in operations associated with the removal of epileptogenic foci. The rationale underlying the abiding interest that the Montreal school developed for the use of local anesthesia is exemplified in an observation of Penfield, who noted that when he and Foerster (Foerster and Penfield 1930) began conducting radical excisions for the treatment of focal epilepsy, large parts of the dominant hemisphere were considered “forbidden territory,” because of the concern of producing dysphasia (Penfield and Roberts 1959, p.103). He noted that “a method of mapping the speech cortex by using electrical interference on the surface at the time of operation” was developed at this time. He went on to indicate that experience with the mapping was responsible in part for “the growing ability to predict speech area limits …” (p. 104). It is a combination of experiences such as this that has given rise to the knowledge of the localization of function in the human cerebral cortex.

Quite irrespective of the location of the epileptic focus, the use of local anesthesia became the standard in Montreal. The Montreal school was so prolific in the training of epileptologists and epilepsy surgeons during the middle of the twentieth century that the use of local anesthesia became a standard at the institutions to which their trainees became attached. Its use was not only a standard at the MNI, but as a result it also became the standard at the majority of surgical institutions worldwide. Because of this and the worldwide influence of the Montreal school, the use of local anesthesia became synonymous with epilepsy surgery, over the early and middle parts of the twentieth century. This synonymy was not seriously challenged until the latter part of the last (twentieth) century.

The challenge to the practice of carrying out epilepsy surgery under local anesthesia became more understandable in the face of a number of rather important advances, which have evolved over the course of some 50 years. These included (1) the increasing experience of surgery, which led to a reasonably standard operative technique, especially in the case of anterior temporal lobectomy (aTLY); (2) the increased knowledge of the pathology and the location of epileptic foci, underlying the seizures of temporal lobe origin, residing in the antero-infero-mesial structures; (3) the increasing lack of dependence upon the intraoperative electrocorticography (ECoG) for the determination of the epileptic focus; (4) the remarkable improvement in identifying small morphological abnormalities through the continually improving medical imaging and the associated correlations between these and the electrographically identified epileptic foci; (5) the rather striking improvements in general anesthesia and neuroleptanalgesia, which, even when intraoperative ECoG is necessary, fail to adversely affect the ECoG, as it did in the early and middle part of the twentieth century; and (6) the use of preoperatively implanted ECoG electrodes, which not only provide evidence of localized epileptogenic discharges but also allow the preoperative electrocortical stimulation, which may provide the necessary functional localization to carry out the eventual operation satisfactorily under general anesthesia.

Why did the use of local anesthesia become such an integral part of epilepsy surgery in Montreal? Probably the primary reason was the dependence of the intraoperative ECoG for the localization of epileptic foci, in the early part of the twentieth century, and the concern of the effect of general anesthesia on the ECoG. The authenticity of this view was derived from a number of observations. Without going into a detailed bibliography in this regard, a single example will suffice. Burns, in 1951, showed the reduction of excitability of electrographic activity in isolated slabs of feline cortex with any general anesthetic. Pasquet noted the deleterious effects of general anesthesia on the ECoGs of patients undergoing operations for epilepsy (1954). In the latter part of the century, there was a strong advocacy against this notion. However, as noted in the foregoing, apparently the improvements in general anesthetic agents have considerably reduced the deleterious effects of general anesthesia on the quality of the ECoG, and, as also noted, this has provided a more justified current challenge to the use of local anesthesia than many years ago.

While the use of local anesthesia is considered by some to be unnecessary, there is also a notion by some individuals that it leads to less satisfactorily achievable qualities of outcome. The reason given for this view is that when patients are awake there are possible restraints placed upon the surgeon as a result of potential discomfort of the patient (Wyler and Hermann 1988). Nevertheless, there is much to be said about the importance of the observations that have been made possible from its use in human patients. There is no doubt that its use in all patients undergoing surgery for the management of epilepsy cannot be justified by simple reference to its historical importance. On the other hand, there is similarly no doubt that in a small portion of operations, at least, it is mandatory (see below) in order to take advantage of the best surgical license. Whereas it is not necessary in most temporal lobectomies and certainly not in the nondominant lobectomies, it is necessary in operations close to, or within, those areas of the cortex, which might be inadvertently injured without the certain knowledge of the location and the function of the juxtaposed cortex involved in the surgery.

The proponents of the use of local anesthesia point out that the many, many observations made from stimulation of the human brain under conditions of awake patients have been of inestimable importance to our understanding of the functional localization within the human neocortex. One of the legacies of these observations is the markedly enhanced appreciation of the safe limits of surgical resection of the cortex. The proponents will also point out that the ease of conducting operations under local anesthesia, when they become necessary, is markedly enhanced when the operating room team has carried out such operations relatively routinely. Finally, a further by-product of the use of local anesthesia is the training of operating room nurses, technicians, young anesthetists, and young surgeons in its characteristics, which then allows them to return to their institutions with comfortable roles in the practice. The latter has certainly been the case at our institution (the University of Western Ontario), where many such individuals in all these disciplines have been so trained over many years. The proper training of operating room teams in the use of local anesthesia in neurosurgical operations also usually results in the likely preclusion of the procedure developing into a miniature three-ring circus on the occasions when the use of local anesthesia is required in their home institutions!

Let us return to the question of whether the use of local anesthesia is necessary. When is it necessary? If all of the above-noted advancements to the conduct of surgery under general anesthesia have been used, then perhaps it might be argued that it is nearly never necessary. However, the argument on the other side pertains to the confidence that the managing team has in these preoperative advances in safely conducting resective operations in the immediate vicinity of the important functional, i.e., eloquent, cortex. If this confidence is lacking in any way, then local anesthesia should be utilized, as surely there can be argument that the safety of the patient and the confidence in the surgical license of the operating surgeon are both significantly enhanced with the patient awake. In most such cases, the resections will involve those areas of the cortex associated with sensorimotor or speech function or the immediately adjacent cortex. This author would always use local anesthesia in these cases.

A discussion of the indications for the use of local anesthesia must be combined with references to those cases in which local anesthesia cannot commonly be utilized (see Table 3.1). There is an age below which local anesthesia simply cannot be employed, even in the face of what is determined to be a patient with optimal behavioral development. This age is usually in the early adolescence period, e.g., 10–12 years of age (see Girvin 1986a). I have had young children in the 9–10 year age group that I felt absolutely certain would be able to undergo satisfactory operations under local anesthesia, but most of the time I was disappointed with these attempts in this age group. Pasquet noted the difficulties with the satisfactory conduct of craniotomies under local anesthesia in this specific age group as early as 1954. The so-called wake-up procedures or the use of deep neuroleptanalgesia has been advocated as appropriate alternatives, but in my hands these have never been entirely satisfactory and certainly never as satisfactory as the crisply carried out, routine awake operations in the appropriately chosen cases. However, in making that statement, it is probably very important to consider the fact that nearly all such procedures many years ago were carried out with barbiturate drugs, especially sodium pentothal, as opposed to the current, much more advantageous, use of intravenous propofol, a short-acting, nonbarbiturate sedative agent (Diprivan™: diisopropyl IV anesthetic).

Other potential patients in whom the use of local anesthesia may be difficult are those in the category of the mentally retarded. In the case of a mentally retarded patient, the judgment of the operating team, on an individual basis, is an important opinion with respect to whether the use of local anesthesia is likely to be satisfactorily achieved. It is worth mentioning that this can be a very, very difficult consultative opinion by which to reach certainty, as it is remarkably surprising how well some such patients do under local anesthesia, when the initial view is that a satisfactory operation almost certainly could not be achieved without general anesthesia. However, this is the exception, not the rule. Finally, there is a small group of patients who, because of the inability to deal with the envisioned anxiety and/or claustrophobia surrounding the operation, simply cannot reach an appropriate level of preparedness. In order to minimize the possibility of the latter, the draping of the patient is of major significant consequence (see Sect. 3.4).

Finally, reference will be made to other alternative strategies to this more traditional method of achieving the advantages of an awake patient under local anesthesia (vide infra, Sect. 3.9).

The most important preparatory undertaking in advance of a neurosurgical operation to be undertaken with the patient awake is indeed the preparation of the patient, per se. The appropriate preparation of the patient facilitates the surgeon’s conduct of the surgery, facilitates the anesthetist’s and nurses’ responsibilities in the operating room, and facilitates the reduction of the normal apprehension and stress of the patient during the procedure. All of these contribute significantly to the ease of obtaining a good-quality operation. Penfield taught that hesitation on the part of the patient to undergo such an operation is probably sufficient to defer the operation (1954).

What is the appropriate preparation? This has been discussed in detail elsewhere (Girvin 1986a) and will be briefly reviewed in the following. In general terms, it is the achievement of a somewhat intangible cognitive and psychological preparedness. It is most important to provide the necessary communication and reassurance that guarantees that the patient understands fully the sequential steps of the procedure, particularly with respect to when he/she may or may not be uncomfortable, and that the whole team is there for one reason—the combination of both the comfort of the patient and the discharge of the individual responsibilities of the team that guarantee the best possible final outcome of the surgery. My own practice is to tell the patient that no matter how important he/she might have perceived to be in other situations, he/she is the most important individual in the operating room on that day. It is easily worth the time that it takes to educate the patients with respect to the anatomy and the pain sensitivity of the structures associated with the operation, e.g., scalp, cranium, periosteum, and meninges, and to advise them as to when these structures are likely to be involved in the operative sequence. In this education, it is important to let them know that the brain tissue, per se, is not associated with pain. (Although the manipulation and cauterization of brain tissue can very occasionally cause discomfort, this is so very, very rare that it does not demand the necessity of a discussion of its possibility!)

The patients should be told that the injections of local anesthetic will be done with a very fine needle such that they may not feel the penetration of the skin from the needle, that they will feel the injection of the local anesthetic per se, that all the injections will take no more than a very few minutes (usually no more than two or three), and that the majority of any discomfort they might feel will be over once the injections have been made. [This is certainly not always true of the operations in the middle fossa, e.g., anterior temporal lobectomy (aTLY), but I have nevertheless indicated such!] This is particularly true with pure central craniotomies when it is uncommon to feel any further discomfort after the scalp injections.

This practice of communication continues throughout the operation. The biggest reason for failure to achieve satisfactory operations under local anesthesia is the failure to continually warn the patient about every possible procedural event that may be associated with discomfort, physical movements of the head, or potentially mechanically disturbing auditory signals. The latter may be no more than the painless use of a curette or rongeurs to trim bone or an air drill producing holes in the bone. The risk of the absence of this constant communication in a patient who is tense, waiting with fear for the next perception of unannounced sudden pain or the sudden crunching of bone, can be catastrophic. Thus, every time bone is to be rongeured, the patient should be told “you are going to hear some crunching of bone, but it will not hurt you … coming … now!” Once patients become aware that everything is announced beforehand, regarding what they might hear or feel, they will relax and be much less anxious participants.

The importance of compassionate anesthetists and nurses, rounding out the operating room team, can similarly not be overemphasized. The fundamentals of compassion and full communication remain the important behavioral characteristics of all members of the team. This will be continually reemphasized throughout this monograph. It is a feeling of accomplishment when the day arrives when the surgeon is aware and appreciative that the combination of the anesthetist and the operating room nurses/technologists has, as a matter of course, simply taken over the prime role of making certain that the patient, in turn, is comfortable and engaged as part of the team.