Facharzt fiir Unfallchirurgie Arbeitsunfallkrankenhaus, Linz, Austria

Transcription

1 THE USE OF DEEP-FROZEN CRANIAL-BONE HOMOGRAFTS IN THE REPAIR OF DEFECTS OF THE SKULL By R. STRELI, M.D. Facharzt fiir Unfallchirurgie Arbeitsunfallkrankenhaus, Linz, Austria IN orthopaedic and traumatic surgery, homoplastic bone transplants have been extensively and successfully used. Cranial bone transplants using homogenous bone, in particular cranial bone, have received little attention. It is reasonable to assume that a cranial defect is best repaired by using bone from the same general area. Cranial bone, because of its shape, makes ideal transplant material. Defects of the forehead including the glabella and orbital margins may be reconstructed with a high degree of accuracy by the use of homologous frontal bone. Abbott (1953) reported three cases of successful homologous bone transplants, using deep-frozen cranial bone, with a follow-up period of eight months. I have operated on, and followed up, twenty-four patients with cranial defects. The largest defect measured 18 by 12 cm. These operations were done at the Unfallkrankenhaus in Linz, Austria, between 1954 and One case with a double defect was repaired in two stages, another in one stage. Two cases with very large defects were repaired in two stages. Preparation of Homograft Material.--The law of 1886 makes.it permissible in Austria to take from a fresh cadaver any material which may be required for scientific or clinical use. In this series cranial bone was taken from accident cases within three hours of death. The bone is removed in the operating theatre through an incision in the coronal plane from ear to ear. It is taken in segments, either in four parts (frontal bone with supraorbital margin, glabella and frontal process, two parietals with squamous temporal, and part of the occipital bone) or in three parts (two half-frontal bones with adjacent parietal and squamous temporal, and occipital bone down to the protuberance). The defect is then made good by sponges soaked in paraffin wax. The posterior wall of the frontal sinus with its lining is removed from the specimen. Pieces of this bone and mucous membrane are cukured aerobically and anaerobically. The segments of each skull are put in a separate, dry, sterile container and stored at -21 C. Case Material.--Twenty-three of the cases had skull defects following the surgical treatment of injuries. There was one case of obliteration of the frontal sinus for infection. Technique of Cranial Repair.--The defect is exposed by reflection of a scalp flap. In the frontal region a coronal hair-line incision is used. The pericranium at the margin of the defect is reflected for I cm. and the bone is freshened by bevelling at 6o degrees to produce a wide area of bleeding bone for contact with the graft (Streli, 1955). A pattern of the outer margin of the defect is made on a transparent Polythene 200

2 DEEP-FROZEN CRANIAL-BONE HOMOGRAFTS IN REPAIR OF DEFECTS OF SKULL 201 sheet. The graft is cut to pattern with a Stryker saw from a piece of preserved cranial bone of the same region as the defect (Streli, I958 a). The graft is cut with a bevelled edge and trimmed with a rasp to an exact fit. In the earlier cases fixation of the graft was by perlon or wire bone sutures. Since I956 fixation has been by Kirschner wires inserted obliquely in the diploe across the junction of graft and host. Usually three are used and the ends are cut off flush with the bone with a diamond burr (Streli, I958 b). The reflected pericranium is laid back over the junction. It is not yet known whether the presence of this fringe of pericranium is essential for the take of the graft. Complieations.--Out of the twenty-four patients, three had post-operative complications. One patient, as a result of the injury, was left with a T-shaped scar over the area of the bone defect. This case was repaired by three separate homografts in two operative stages. Four weeks after the second stage was completed there was a breakdown in the centre of the scar. This left an ulcer 3 mm. in diameter with no signs of severe inflammation. This was due to the tension in the scar tissue over the bone graft. One of the three implants was therefore removed. The second case had a complication due to the suture material. A granuloma developed within a few weeks of operation in three different parts of the wound. This case had been given Dacortin (prednisolone) for five days after operation. After removal of the buried perlon sutures, the wounds healed over the denuded implants by granulation. It is interesting to note that infection did not cause sequestration of the graft. The third complication was an abscess surrounding a subcutaneous perlon suture six weeks after the plastic repair. It perforated and a fistula developed. The wound was reopened. The outer surface of the graft was found to be adherent to the scalp and showed early revascularisation. Beneath the graft was a dead space filled with a jelly-like exudate. The space was due to cerebral atrophy following COntusion. The temporal part of the bone flap was resected and the frontal part left intact. Another patient, who had had a successful homologous cranial-bone transplant eighteen months previously, was killed in an accident. It was possible to examine the grafted area at autopsy and to submit the material for histological examination. As these findings are of considerable interest, the case is reported in detail. CASE REPORT Patient W. K., aged 46, construction foreman (AZ : FI846/56, F3173/56). Admitted on 25th May I956 with an open fronto-basal depressed fracture. The dura was also torn. The accident was caused by a large piece of concrete which fell from a height of IO metres. The patient, on admission, had regained consciousness and was vomiting. The skin was lacerated and showed a stellate wound about 3½ cm. in size. X-ray showed a depressed fracture of the right frontal bone of approximately the same size as the skin wound, and fractures radiating down to the base of the anterior cranial fossa. While being treated for shock he had two Jacksonian fits and a generalised fit of the grand-mal type. The wound was debrided and the fractures exposed by a reflected scalp flap. The depressed bony fragments were removed and the edges made smooth. The area of contused brain was removed by suction, and the dural wound closed. An opening into the frontal sinus was dosed with Spongostan. The patient was discharged from hospital symptom-free eighteen days later. On 24th August I956 he was readmitted complaining of intermittent headaches and dizzy spells. Examination showed a pulsating defect 4 cm. in diameter in the region of the frontal bone. He also complained of being stared

3 202 BRITISH JOURNAL OF PLASTIC SURGERY at, and had become self-conscious about the deformity. There were therefore very good indications for cranioplasty. At operation on 25th August I956 a frontal flap was reflected and the bony margins of the defect freshened. The margins were cut at an oblique angle until bleeding bone was reached. A homologous deep-frozen piece of frontal bone was cut to fit the defect. Four perlon sutures were used to secure the bone in place. In order to prevent fluid accumulation under the graft, and in order to help its revascularisation, holes were drilled at various points on the surface (Fig. I). The reflected flap was then sutured in layers FIG. I Frontal defect at operation, 25th August 1956, showing the homogenous bone graft sutured into place with five perlon bone sutures. Multiple drillholes have been made in the graft to facilitate revascularisation. A fracture line is visible at about 6 o'clock which has not united three months after the accident. and the patient kept in hospital for nine days before discharge. The wound healed by primary intention. The skin over the bone graft was slightly adherent but the normal contour of the forehead had been restored (Fig. 2). Sixteen months later, X-ray showed that the transplant had been successful. The junction between the graft and the host was no longer visible. At the centre of the graft was an area of increased density (Fig. 3). In the first year after operation the patient had only one attack of unconsciousness. Electroencephalogram showed a normal pattern ; Pickerill (I947) regards this as an important point in the follow-up of cranioplasties. He was assessed for workmen's accident compensation as nil disability for the scalp and skull, and as 3o per cent. disability for the underlying brain damage. The latter was reduced to 2o per cent. a year later. In I958 this patient was involved in a motor cycle accident which proved fatal. At the autopsy I was able to recover the original transplant and also the neighbouring bone. Macroscopically the graft appeared to be replaced by living, vascularised bone. About half of the border of the graft could not be distinguished from host bone. Four shallow depressions had been formed by absorption around the original bone sutures. Some of the holes drilled through the bone were dosed and others enlarged (Fig. 4). The histological preparation showed nearly complete peripheral bone replacement,

4 DEEP-FROZEN CRANIAL-BONE HOMOGRAFTS IN REPAIR OF DEFECTS OF SKULL 203 the centre being only partially replaced. The centre showed zones of absorption comparable to enlarged Haversian canals of different sizes. A vascularised fibrous marrow was found in the areas of absorption. Some new bone was found on the inner surface of the lactm~e, demonstrating the gradual bone replacement. Osteoclasts were not found. The peripheral bone areas showed spicules of dead bone lying within newly formed bone. Inflammatory reaction was not seen. The marginal areas of the transplant showed FIG. 2 Same case fifteen months later. A, The contour of the forehead is restored. B, The mobility of the soft tissues over the graft is diminished. definite outer and inner tables of live bone. The centre showed less differentiation, the transition being a gradual one. The differentiation of the inner table had spread farther towards the centre than the outer table (Figs. 5 and 6), DISCUSSION Deep freezing is the most effective method of preserving bone for clinical use. Bone homografts appear to be replaced by host bone after several years. X-ray follow-up studies and the reported histological examination have demonstrated that it takes two to four years before replacement is complete. Pickerill (I947), Grocott (I953), and Sch6nbauer and Winkler (I955) have shown that autografts are successful in the repair of cranial defects, although in some there is partial absorption (Grocott, I953). Cranial bone homografts, preserved in various ways, have been reported since i9i 7 but have fallen into

5 204 BRITISH JOURNAL OF PLASTIC SURGERY FZG. 3 Same case. A, 29th May I956. Defect in the frontal bone after primary treatment. B, 26th August z956. Homograft one day after insertion. C, 3oth December I957. Homograft sixteen months after insertion. The graft appears smaller because the marginal areas are replaced by host-bone. There is some absorption at 12 o'clock and around the small drill-holes. The centre of the graft is more opaque.

6 DEEP-FROZEN CRANIAL-BONE HOMOGRAFTS IN REPAIR OF DEFECTS OF SKULL FIG. 4 Same case. Specimen obtained at a u t o p s y on 7th April 1958, t w e n t y m o n t h s after grafting. T h e graft was well vascularised and, over half its circumference, firmly u n i t e d to the skull. FIG. 5 Section of t h e centre o f the graft T h e centre shows creeping substitution. T h e diploeic canal is revascularised ; t h e m a r g i n of the canal is lined b y osteoblasts. T h e adjacent bone shows vacuoles conzaining wellstained nuclei of bone ce!is. T h e other parts of t h e graft show no nuclear staining. Appositional bone g r o w t h is a p p a r e n t in t h e area o f a lacuna on the i n n e r surface of the graft. 3B 205

7 206 BRITISH JOURNAL OF PLASTIC SURGERY FIG. 6 Same case. 34 o. Living bone cells near donor bone that has not revitalised. ~[It clearly shows the creeping replacement. There are no osteoclasts to be seen but there are osteoblasts, probably arising from the primitive vascular mesenchymal cells of the host. disfavour; none of these were preserved by deep freezing. Reeves (I950) concluded that it seemed unlikely that plates of deep-frozen homografts could be used satisfactorily for replacement of a large defect, but that further experimental work would be interesting. Of twenty-four homografts reported in this paper, twenty-one were satisfactorily incarporated in the host, and gave a good cosmetic result. It was even considered that in some of the cases the final result was possibly an improvement on the appearance before injury. This technique might be used

8 DEEP-FROZEN CRANIAL-BONE HOMOGRAFTS IN REPAIR OF DEFECTS OF SKULl. 207 for the repair of certain congenital malformations of the forehead, whereby an abnormal frontal bone would be replaced by a homograft of normal contour. SUMMARY I. During a period of four years, twenty-four cranioplasties using deep-frozen homologous cranial bone were carried out. 2. In twenty-one cases the grafts took well and there was a satisfactory cosmetic result. 3. There were three cases of local infection. 4. One case is reported in detail with macroscopic and microscopic examination of the graft twenty months after insertion. 5. The human forehead after loss of bone is greatly disfigured. Repair with homogenous frontal bone, because of its shape, gives an excellent cosmetic result, especially when the orbital margins, glabella, and supraciliary ridge are involved. I would like to thank Mr T.J.S. Patterson for his help in the preparation of this paper for publication. REFERENCES ABBOTT, K. H. (1953). ft. Neurosurg., 1o, 38o. GROCOTT, J. (1953). Brit. J. plast. Surg., 5, 51. PICKERILL, H. P. (1947)- Brit. ft. Surg., 35,204. REEVES, D. L. (195o). " Cranioplasty." Springfield, Illinois : Charles C. Thomas. SCH6NBAUER, L., and WINKLER, E. (1955). Acta neurochir., Suppl. 3, 4. STRELI, R. (1955). Arch. orthop. Unfallchir., 47, (1958 a). Arch. orthop: Unfallchir., 50, (1958 b). Amer. J. Surg., 96, 7Ol.