Emigration of Greek Knowledge to the Arab World.

The period described in this chapter reflects activity prior to the establishment of surgical centers in Europe in the twelfth century. It is a kind of prologue to the reintroduction of high-quality surgical practice. Religious squabbles within Christianity led to European medicine and surgery, the principles of which were written in Greek, being transported eastwards into the region newly dominated by Islam. There the works were translated into Arabic and during three to four hundred years, the works were not only retained but were enriched by contributions from within Arab culture. This evolution naturally enough came to affect what happened next. However, one thing is clear and was even commented on as early as by Albucasis. The surgeon's respect and distinction within society had depreciated during the sojourn of medical science in the Islamic world, with physicians being regarded as distinctly superior beings. With regard to specific details related to opening the head there was broad consistency between the various authors all of whom seem to have been greatly influenced by Paul of Ægina. Thus, there is no mention of the crown trepan. Opening the skull was performed with the non-perforating trepans making small holes which were connected with chisels or lenticulars. The indication to do this was separation of the dura from the bone. Whether or not the sutures should be avoided when trepanning is not a topic mentioned in these writings. There was also no recommendation for prophylactic trepanation.

Late Middle Ages-Europe.

At the end of the late Middle Ages, there had been changes in indications for surgery, with prophylactic trepanation falling out of favor. The management of wounds and the methods for opening the cranium had become fairly standardized. Narrow non-plunging trepans were the preferred drills, and cranial openings were widened by the use of multiple drill holes connected with chisels of which the lenticular was preferred. Concerns about damaging the dura led Theodoric to delay trepanation until the clinical changes reflected separation of the dura from the cranium, at least in his view. Draining pus remained the main indication for trepanation. In no case was the level of consciousness considered in determining the need to open the cranium.

Basic considerations.

The chapter reviews certain topics in outline. It starts with a brief account of the nature of surgery. This is followed by a short account of modern management of cranial trauma including the evolution of notions of anatomy and pathophysiology. It is emphasized that these principles are and must be irrelevant to the management of cranial trauma in the period covered in this book from Hippocrates to the end of the 18th century. Historical errors arising from assuming modern principles applied in historical practice are mentioned. Finally, the risks inherent in accepting images without questioning their authorship and provenance is also mentioned.

Trepanation technique.

The larger part of this chapter is concerned with the technique of drilling the cranium with a circular saw called a trepan or trephine. The terminology of the instrument is outlined. Safe use of the instrument includes probing the groove produced by its use and angling the drill so that it impinges on bone which hitherto has not been sawn through. There is then an account of how larger openings may be made by drilling multiple small holes and connecting them by means of a chisel.

Hippocrates (ca 460 BC to ca 370 BC).

The chapter begins with a review of some of the background thinking during Hippocrates time. The brain was considered to be the location of the soul which was the essence of subjective experience. However, this was not a brain function as such but rather a location where the pneuma reacted with the soul. Hippocrates' monograph on cranial trauma begins with a description of the bones and sutures. He then systematized the classification of cranial injury. He sensibly advised accurate diagnosis into one of the types of injury he described and supported extension of any skin opening to facilitate diagnosis of the bone, the injury of which was his primary concern. His description of operative technique has rarely been surpassed, placing emphasis on care and methods for the avoidance of further injury. He also emphasized the importance of probing during trepanation to avoid damaging the dura and underlying brain. In addition, he insisted on using water to cool the trepan. All of this was positive. However, the respect in which he was held in subsequent generations meant that two albeit understandable errors were perpetuated. The first error was the use of prophylactic trepanation to permit the drainage of the pus which he believed would inevitably develop under a fissure. The second was to avoid trepanning at sutures, the reasons for which proscription are not clearly stated. In conclusion, it may be noted that what limited reporting of results is available demonstrates that Hippocrates trepanations were largely not successful.

Rome-Galen (129 to ca. 216).

Over the last 50 years the significance of Galen's contributions to the arts of medicine and surgery have been increasingly recognized. Despite his errors, his contributions to medical and surgical practice have been profound. In the present context, his teachings on cranial surgical instruments and technique would continue to be influential throughout one and a half millenia. His technical advice was sound. His error about the anatomy of blood vessels supplying CNS were not of much consequence since the CNS would remain surgically inaccessible until the end of the 19th century. He reclassified fractures as extending to the diploe or through the internal table. Moreover, they could be simple, comminuted, depressed, or elevated. He did not mention indications or clinical changes, on the other hand he had many sensible remarks to make on the instrumentation required for cranial surgery. As will be seen in what follows, he was much quoted in justification of the decisions of his successors. The major errors of significance related to his description of the anatomy of the cranium and its sutures. His concern about the cranial attachment, vascular components and excretory functions of the sutures added to Hippocrates' concerns about their inherent weakness resulted in the teaching that trepanation should avoid these structures. This was to have a limiting effect on the placement of trepanation openings which was of no benefit to the patients. Moreover, his enthusiasm for bloodletting would also serve to potentiate Hippocrates teaching on this matter, to the advantage of nobody.

Europe following Galen.

Unlike previous chapters, this is not about the teachings of a specific individual. Rather, it traces the slow changes in milieu and practice in the centuries following the death of Galen. They were to be profound. The Roman Empire fell in the middle of the 5th century. The Christian religion became increasingly dominant in the west, not only in spiritual matters but also in every activity related to culture and learning. The Byzantine Empire became increasingly important in the east. Islam was founded and began to spread in competition with Christianity. Academic advances develop best in stable societies so that it is not surprising that this was not a period of new ideas. Galen had gained overwhelming authority. The most valuable work on surgery to be written during these times was Book VI of Paul of Ægina's encyclopedia.

Prehistoric or current primitive cranial operations.

Humankind demonstrates boundless curiosity, mostly expressed through the activities of a small number of individuals, whose achievements affect all members of society. The extent and distribution of pre-historic trepanation and trepanation in contemporary unsophisticated societies are reviewed. In the great majority of cases the intention of trepanation has been therapeutic, even if the understanding of underlying pathophysiology is not the same as that which scientific societies now accept. This review demonstrates variation in surgical technique. In the Atlas Mountains it was unacceptable to operate on the cranial sutures whereas in New Ireland it was not important. Pain relief was unnecessary in Melanesia because the patients were largely unconscious following injury. In South America, there was access to the coca leaf which could help with pain relief. In East Africa, one patient described the application of a powder to his wound which was thought to be for pain relief. The nature of the powder remains unknown. There were differences in the indications for trepanation. In New Britain, the operation was performed only for cases of fracture. In nearby New Ireland, epilepsy and certain forms of mental disturbance were also indications. In North and East Africa, the indication was most frequently headache following trauma. Most of these trepanations did not involve drilling, which is the main subject of this book.

Outside Europe.

This chapter illustrates that cranial surgery was not limited to Europe. There was however no contribution to improving knowledge outside Europe until medical science departed for the Arab world.

Anatomy after Hippocrates.

This brief chapter has a single purpose which is not directly related to cranial surgery. However, between Hippocrates and Celsus and Galen a number of improvements in the understanding of anatomy had been discovered and this chapter briefly outlines the nature and importance of these advances.

Rome-Celsus (ca 25BC to ca. 50AD).

Celsus gave an adequate description of the bones and sutures of the calvarium. His classification of injuries was simple including fissures and depressions. He is the first to relate specific symptoms to specific tissue injury. In addition, he was aware that fractures could be present in the absence of typical findings. He was also the first to note the meningeal vessels could rupture producing severe localized pain. His treatment was more conservative than that of Hippocrates. Plasters were to be used and if there was no deterioration trepanation was avoided. He described the use of the crown trepan (modiolus) and the instrument with a smaller tip which expands rapidly to prevent penetration. He also described the technique of rotating the trepan between the palms. His description of operations for depressed fractures were unusually clear and relevant even by modern standards. His wound care is strikingly different from that of Hippocrates as he advocates various dressings soaked in vinegar and as time passes plasters should be softened with rose oil. Regrettably, Celsus influence would not be felt until the time of the Renaissance, because his texts were lost. However, his "De Medicina" was rediscovered and became the first medical text to be published using the new moveable type printing press, in the year 1478. Thus, his influence was minimal in the Arabic world and the early Renaissance. Thereafter it was profound.

The Lenticular.

OBJECTIVE: The lenticular was an instrument introduced by Galen to facilitate cutting the bone of the cranium. Illustrations of the instrument first appeared in the 16th century during the Renaissance. These illustrations have been widely used, but the instrument's shape seems ill-adapted to its function. Archaeological research in Rimini, Italy, unearthed a similar instrument with a shape that seems more suitable for the function of cutting cranial bone. The object of this study was to evaluate the efficacy of these two instruments for cutting the bone of the cranium. METHODS: Replicas of the two instruments were obtained. Trepanation was performed in the left parietal region of a sheep's head. In addition, the application of the instruments in the literature was analyzed. RESULTS: The Roman lenticular cut the cranium with ease. The Renaissance instrument failed to cut the bone and only separated the dura mater from the bone. The lenticular had been used to cut bone up to the 13th century. In contrast, the Renaissance instrument was not used to cut bone but to smooth roughened bony surfaces and to remove spicules of bone that were in contact with the dura. CONCLUSIONS: Analysis of illustrations in medical publications should be undertaken with the same rigor as applied to analysis of text.

Cranial surgery and the pericranium.

In contemporary neurosurgery little attention is currently paid to the pericranium. The purpose of this article is to present how past surgeons have viewed this membrane and how they have reacted to its appearances. In ancient times, the pericranium was considered formed by the dura through the sutures and it retained a relationship with the dura via vessels in the sutures. It was considered advisable to strip it totally from any area to be examined for fissure fractures and also for any area to be trepanned, as pericranial injury led to fever and inflammation. In the eighteenth century, a new idea arose that posttraumatic spontaneous separation of the pericranium from the bone was a reliable indicator of the development of intracranial suppuration. This idea was subsequently refuted. The development of the osteoplastic bone flap imposed on the surgeon the need to ensure postoperative craniotomy closure included accurate apposition of the margins of the pericranium. With modern free bone flaps, this is no longer required. For over two millenia, the pericranium was considered to be an important membrane requiring the close attention of the surgeon. It is no longer required to receive more than minimal attention.

History of Cranial Trauma Surgery and the Meninges.

OBJECTIVE: To trace the evolution of ideas and practice in the management of meningeal injury from the ancient world to the end of the 18th century. MATERIALS AND METHODS: The texts of significant surgical practitioners from Hippocrates to the 18th century were examined and analyzed. RESULTS: The dura was first described in ancient Egypt. Hippocrates insisted that it should be protected and not penetrated. Celsus proposed an association between clinical findings and intracranial damage. Galen proposed that the dura was attached only at the sutures, and he was the first to describe the pia. In the Middle Ages, new interest in the management of meningeal injuries arose, with renewed interest in relating clinical changes to intracranial injuries. These associations were neither consistent nor accurate. The Renaissance brought little change. It was in the 18th century that it became clear that the indication for opening the cranium following trauma was to relieve pressure from hematomas. Moreover, the important clinical findings on which to base an indication for intervention were changes in the level of consciousness. CONCLUSIONS: The evolution of the management of meningeal injury was colored by erroneous concepts. It was not until the Renaissance and finally the Enlightenment that a milieu developed that permitted examination, analysis, and clarification of the underlying processes that could lead to rational management.

The historical rationale for operating on cranial fissures.

OBJECTIVE: Cranial fissures are not an indication for surgical intervention. It should be emphasised that the term fissure refers to linear skull fractures as defined in MESH. However, it was the universal term for this injury in the literature which forms the basis of this paper. Nonetheless, for over two millennia, their management was a major reason for opening the skull. The reasons for this deserve analysis, in particular taking into account the available technology and conceptual background. MATERIALS AND METHODS: The texts of significant surgical practitioners from Hippocrates to the eighteenth century were examined and analyzed. RESULTS: The need for fissure surgery was based on Hippocrates' teaching. It was considered that extravasated blood would suppurate, and extracranial suppuration could leak inwards through a fracture. Trepanation to facilitate pus drainage and cleansing was considered vital. Avoiding surgical damage to the dura was also emphasized with a preference for operating only when the dura had separated from the cranium. The enlightenment with an increasing reliance on personal observation rather than the teachings of received authority enabled the accumulation of a more rational basis for treatment concerned with the effects of injury on brain function. This culminated in the teachings of Percivall Pott, who despite some minor errors, provided the framework on which modern treatments would develop. CONCLUSIONS: Examination of the surgical management of cranial trauma from Hippocrates to the eighteenth century shows that cranial fissures were judged to be of great importance and required active treatment. This treatment was not aimed at improving the healing of the fracture but at avoiding deadly intracranial infection. It is worth noting that this sort of treatment persisted for over two millennia while modern management has only been practiced for just over a century. Who can say how it will change in the next hundred years.

A history of the surgery of the cranial sutures.

INTRODUCTION: While the calvarial sutures have a limited importance for the modern neurosurgeon, they were of considerable interest to cranial surgeons from the time of Hippocrates onwards. The reasons for this interest together with the evolution of ideas are the subjects of this paper. MATERIALS AND METHODS: The texts of surgeons from the time of Hippocrates to the eighteenth century have been studied and analysed. RESULTS: Hippocrates advised against trepanation through a suture without specifying why. Galen taught that the dura was only attached to the interior of the calvarium at the sutures. The first author to state that the attachment was diffuse was Berengario da Carpi, at the beginning of the sixteenth century. This teaching was subsequently ignored until the eighteenth century, from which time it has been universally accepted. It was also first emphasized in the eighteenth century that it was not dangerous to trepan at the sutures. CONCLUSIONS: This study documents the persistence of incorrect ideas from classical times to the middle of the eighteenth century. These notions would have limited the regions available for surgical access to the skull and thereby limited the benefits to be derived from surgery.

A glance at the past.

The chapter is aimed at reminding users of some early findings which are difficult to understand on the basis of currently accepted notions of the practice of GKNS. Two patients with trigeminal neuralgia and one patients who required a tractotomy achieved clinical improvement despite very low doses by modern standards. One early AVM was occluded with the dose directed simply at the feeding arteries. Patients with vestibular schwannomas suffered only temporary facial pareses despite receiving a dose to the facial nerve of 40Gy or more. It is suggested finding explanations for these unusual findings could be interesting. The chapter closes with comments about certain characteristics of published reports which could be perhaps be adjusted with benefit to all.

Cavernous malformations.

Cavernous malformations are relatively common intracerebral malformations of which we only became properly aware after the introduction of MRI. They may be sporadic or familial. Familial CMs may be multiple and new lesions appear over time requiring intermittent MR control. Many sporadic CMs have no symptoms. The commonest location is in the supratentorial cerebral parenchyma presenting with epilepsy. The best treatment is microsurgery. A small proportion are in the brainstem and may rebleed and even be lethal. Treatment includes microsurgery and radiosurgery. Microsurgery cures the patient but has substantial problems with complications, deterioration and partial removal. Radiosurgery has taken time to demonstrate that it can over 2 years substantially reduce the risk of rebleeds without the risks of microsurgery. Both methods have a part to play in the treatment.