TREPHINATIONS – OLD SURGICAL INTERVENTION

HISTORICAL VIEW

First trepanated skull was discovered in 1868 by Prunieres in France. He later collected 168 prehistoric discoveries. In the Czech Republic skull trephination was first discovered and described by J. Pudil in 1876. He found two skulls at the graveyard near Strupčice, West Bohemia. This discovery triggered a tendency to start collecting trepanated skulls, as described by Matiegka (15, 16). In recent years the topic of trepanations has mainly been analyzed in archeological publications (7, 10, 13, 18, 22–26). About 90% of the skulls were older males.

The term trephination comes from the Latin term trepanum, which means drill and from a Greek term trypanon (I am drilling). The universal definition of trepanation is quoted as an opening of a cavity covered by bone, most commonly in the skull; however, it can be associated with any bone or tooth (19). During his study of historic findings Matiegka (15, 16) and Vlček (23) described and divided trephinations into three groups: complete, incomplete and cauterization (burning). Complete trephination is characterized by the perforation of the external lamina, diploe and internal lamina. During an incomplete trephination the external lamina and/or diploe is removed, but the internal lamina remains intact. Cauterization is intervention with a hot object which causes damage or complete burning of the bone and its perforation; instead of infection it causes necrosis and aseptic inflammation which subsequently heals well. Manouvriere described scars on skulls found near Paris which had been caused by gradual burning which led to an opening. This type of intervention is described as far back as by Herodotos as well as Arab doctors in the 11^th and 12^th centuries.

In historical times as well as in today’s native cultures the most common method of performing trepanation is by scratching, which leads to a gradual removal of bone layers and the formation of a round opening with a wide oblique edge, larger in the area of external lamina. Another technique is cutting and drilling, and here we can also include the method according to Lucas-Championniére (12). During the cutting deep grooves are created by a sharp object; these mark the trephination opening and establish its shape, most commonly a square. Eventually the bone is extracted. Drilling can be performed in two ways. When a drill is used its size determines the final size of the opening (circling), while a trepan – an instrument intended only for trephinations – can also be employed. The method of Lucas-Championniére uses a sharp edge for drilling small openings which are organized in a circle and are connected by cutting; forceful opening follows, and the jagged edge of the opening is smoothed by scraping. This type of intervention (drilling followed by forceful opening) is risky, because it can lead to damage to the meninges of the brain. The broken part (roundel, French rondelle) is characterized by a jagged edge and can show signs of drilling, cutting or scraping (16). Peruvian Indians most commonly used this technique, according to Lucas-Championniére, or bone drilling using chisel-like instruments (22).

Trephinations were performed by sharp objects (flint or metal blades). In approximately 25–75% of operated skulls signs of healing of the edges of the openings were found (19). However, in many cases, due to the short healing period, it is not possible to determine if the surgeries were completed during the person’s lifetime or posthumously (2). Cases of multiple trephinations are also known, when the primary opening was widened or   a new opening was created. In the area of Cuzco in Peru a skull was found with seven trephinations showing obvious signs of regeneration, and it is likely of course that the person in question survived the interventions (13).

Obtaining a roundel from a skull or experimenting with surgical intervention could have been reasons for postmortem trephination. In unhealed trephinations marked signs of instrumental intervention are usually found, corresponding to the technique used (21).

The oldest documented cases of trephinations are from the Neolithic era; the oldest finding in Europe so far comes from French Ensisheim and is about 7000 years old (1). The orifice 6.5 x 6 cm on the centre of frontal bone was completely closed; the second larger trepanation over both parietal bones (9.5 x 9 cm) was partially healed. Trephinations were found not only in Europe but also in America, mainly in Peru and in Mexico, where this type of intervention was very common (present in about 10% of the found skulls). On Pacific Ocean islands or in Africa this intervention is done in primitive conditions and with simple instruments by native medicine man even today. As far back as 1928 Broca thought this surgical technique had been used in northern Africa from ancient times right up to the 20^th century.

In classical as well as medieval medical literature, ever since the times of Hippocrates, we can find instructions on performing trephinations, raising the question of whether classical medicine accommodated the method from ancient folk medicine. It is interesting that discoveries of prehistoric trepanated skulls became an impulse for the study of trephination at the end of 19^th century, because until then this technique was rejected by doctors and believed to bring about certain death (15).

Trials on dead people’s skulls and animals proved that it was really possible to complete trephinations in prehistoric times by using only flint instruments. Broca accomplished this intervention by scratching on the head of an adult in an hour and in a child within four minutes; Lucas-Championniére completed the operation in 35 minutes with his method (15, 16).

It is likely that areas for trephinations were not selected accidentally; at the same time, anatomical rules were not taken into special consideration. Skull sutures were not considered an obstacle, and on several skulls the intervention was completed near meningeal arteries; sometimes the trephination opening was even above the sagittal suture and above the large vein sinus (1, 15). Reasons for performing trephinations vary. In ethnologic studies (11) these are divided into three areas. Firstly, therapeutic, where trephination was completed purely as a form of treatment (for head injury, concussion of the brain, increased intracranial pressure). Secondly, magic-therapeutical, which assumed that medical problems are caused by demons and it is necessary to “let go” of them (long-term headaches, vertigo, convulsions, epilepsy, and mental disorders). In these cases the resulting effect is comparable with the therapeutic. In the third case, for magical-ritual reasons, a healthy individual undergoes surgery as a magic protection against possible future injury or illness. This is not very likely, though as documented in a Kenyan case from 1970, it can happen sporadically. Similarly, in postmortem trephinations the roundel extracted served as a precious amulet (13, 22).

For a diagnosis of the origin of the opening it is important to consider other causes as well: For example, enlarged parietal foramina, congenital herniation, tangential cutting injury, impressive fractures of the cranial bone, thinning or perforation due to osteoporosis, bone cysts, benign or malignant tumors or bone infections during tuberculosis, syphilis and osteomyelitis. Biological and microscopy methods can help to clarify it or illustrate the facture. 

COLLECTION OF HRDLIČKA MUSEUM

In the Hrdlička Museum of Man, Charles University, 12 more or less well-preserved trephined skulls from various periods are stored. Anthropologic and anthropometric analysis, which is not presented in this paper, could be performed on 9 skulls of which 5 belonged to males, one to a female and three were of uncertain sex. Four skulls were in the category adultus/maturus, one senilis and four were too much impaired for age determination. Signs of bone healing, indicating the survival of the patient, were evident in 4 skulls, two skulls did not show any signs of healing and in three skulls survival of the patient was impossible to establish. On one skull there were two trephination holes (Fig. 1), while the other skulls had one hole. They were located on os frontale (4x), os parietale (3x), os occipitale (1), on sutura lambdoidea (1) and sutura coronalis (1). Five skulls were from the bronze period, while the origin of the others is not known. In three of the skulls CT and histopathological analysis was performed. 

Computed tomography examination

Three of the skulls having oval-shaped holes were examined. The purpose was to find an answer to the main question: did these people live after suffering such a major head trauma?

Each skull has been separately examined using Computed Tomography (CT) (Siemens Sensation 40, 2006, Erlangen, Germany). Helical examination mode has been chosen using 120 kV, 360 mAs for scanning a normal head. Twenty detectors in a row have collected the data in 0.6 mm thickness, total pitch 0.5. In recon mode all data have been reformatted into 0.6 mm slices, increment 0.3 mm kernel 10 used for 3D modelling and at the same width kernel 60 for better resolution of bone structure. Each skull has been shaped in a 3D model in various rotations using volume-rendering technique (VRT).

Skull No. 1 (Fig. 2–4)

The skull was found in Strupčice, West Bohemia. The oval hole is located only in the squama of right parietal bone. The inner measurement is 38 mm cranio-caudal and 38 mm antero-posterior, in anterior oblique 52 mm and posterior oblique 32 mm. No other traumas such as fractures or fissures are visible outside or inside the bones of the skull. The inner edges are smoothly rounded with no defects. The edges are within the borders of the proper cortical bone. There is no spongious bone on the edges of the hole. This indicates that the person was able to live for quite a while, at least six months, after surgery. The trauma of the bone had enough time to produce enough cortical bone to smoothen the edges; there is almost complete ossification of the edges. There is no real visible evidence of infection or other defects.

Skull No. 2 (Fig. 5, 6)

The skull was found in Chrabřec, North-West Bohemia. The oval hole is located in the centre of the squama of the left parietal bone. The inner measurement is 28 mm cranio-caudal and 38 mm antero-posterior, in anterior oblique 29 mm and posterior oblique 44 mm. On the calva there is a sharp cut-like trauma removing the outer cortex of the bone over a much bigger area than the inner cortex. The spongious bone is uncovered. There is no particular sign of re-ossification. The trauma was probably made by a sharp object with one tangential cut. The outer cortex is cut 10–13 mm wider than the inner cortex. A straight anterio-posterior line of fracture is located dorsal to the hole on the left parietal bone finishing in the parieto-occipital suture. There is no evidence of healing processes in the bone. It can be assumed that this person has died soon after the head injury.

Skull No. 3 (Fig. 7, 8)

The skull was found in Prague (Svatý Mikuláš). The oval hole is located in the dorsal part of squama of right parietal bone. The inner measurement is 25 mm cranio-caudal and 14 mm antero-posterior, in anterior oblique 28 mm and posterior oblique 13 mm. On the calva there is sharp cut-like trauma with a V-shape removing the outer cortex of the bone over a much bigger area than the inner cortex. The trauma was probably made by a sharp object with tangential cuts chopping in and out to make the V-shaped cut. The outer cortex is cut 7–16 mm wider than the inner cortex. The spongious bone is not covered by cortex. There is no particular sign of re-ossification. There is no visible trauma such as fractures or fissures outside or inside the bones of the skull. There is no evidence of healing processes in the bone. It is assumed that this person died soon after the head injury.

Results

CT examination has been performed on skulls from bronze period with one hole in parietal bone on either side. The measurements were taken from 3D images (see Fig. 4); the distortion of VRT images could cause slightly different values than the real measurements.

There is evidence that in one case (No. 1) the person lived with this injury for quite a long period of time, because there is almost complete re-ossification of the edges with new cortex on the edges visible as smoothness of the edges. There is no way of determining how the injury occurred.

In cases No. 2 and No. 3 there is no evidence of re-ossification on the edges of the holes. The injuries were probably fatal or led to early death. A sharp object such as a knife, sword or axe probably caused the traumas in both cases. This is suggested by the bigger cut off area on the outer cortex than on the inner cortex.

Histopathological analysis

Samples of skull bones were taken from three cases in the region of the margin of the defect. The cut was oriented perpendicularly to the margin of the defect. Specimens removed from this area were placed in formalin for one day and than dehydrated and embedded in paraffin. Microtomed sections 7 micrometers thick were stained with haematoxyllin and eosin and Masson’s trichrom.

During histopathological examination of bone specimens removed from the edges of the defects two different patterns were observed.

An examination of the sample removed from skull No. 1 showed that the margin of the defect was covered by cortical bone of an identical structure as the cortical bone of the surrounding skull bones. No defect or other pathological changes were identified in this site. Continuity of this cortical bone with the cortex of the inner and outer skull surface was apparent (Fig. 9).

The histological finding in the margin of the defect of skull No. 2 was completely different. The margin of the defect was not covered by bone of the cortical type. No signs of healing in this region were observed. The inner and outer cortical bone of the skull ended sharply, and between them there was cancellous (spongy) bone with free surface (Fig. 10) lacking in cortical bone.

Acknowledgements

This study was supported by Research grant of Ministry of Education, Youth and Sports MSM 0021620843, and by grant of Ministry of Health IGA No. 8150-4. 

Address for correspondence:

Božena Škvařilová

Hrdlička Museum of Man

Faculty of Science, Charles University

Viničná 7

128 44 Prague 2

Czech Republic

E-mail: bozena_skvarilova@centrum.cz