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Anterior cranial base reconstruction using a hydroxyapatite-tricalciumphosphate composite (Ceratite®) as a bone substitute
Anterior cranial base reconstruction using a hydroxyapatitetricalciumphosphate composite (Ceratite ®) as a bone substitute Tatsuo Nakajima 1, Yohko Yoshimura 1, Yuji Nakanish?, Tetsuo K a n n o 2, Hirotoshi Sano 2, Yoshihumi Kamei 2
1Department of Plastic and Reconstructive Surgery (Head: Prof. T. Nakajima), 2Department of Neurosurgery (Head: Prof. 7". Kanno), School of Medicine, Fujita Health University, Japan
S U M M A R Y . The craniofacial approach to cranial base tumors has widened the operability of tumors with intracranial invasion. However, the resulting skull base defect must be reconstructed adequately to prevent postoperative morbidity and mortality. We use hydroxyapatite-tricalciumphosphate ceramic (Ceratite ®) as a bone substitute material to reconstruct the skull base defect in combination with the pericranial flap, ensuring separation between the sinonasal cavity and epidural cavity. Although the nasal surface of the Ceratite ® block is left exposed directly to the sinonasal cavity, it was shown to be epithelialized within 6 months postoperatively. Our method is less invasive than any other conventional method and may offer more chance of curative resection of tumors with anterior skull base invasion.
cision, then a pericranial flap was elevated and draped over the scalp flap for later use. A bifrontal osteoplastic craniotomy was performed and a supraorbital bar of bone was removed to widen the operative field (Fig. 1). Then a wide resection of the tumor was commenced. Any tumor invading the sphenoid or ethmoid sinuses, or into the orbit or nasal cavity was resected. Paranasal cavities which showed inflammatory change were drained. Hypertrophic mucosa, the nasal septum and conchae were removed when they were encroaching into the operative field. The nasal, ethmoidal, and maxillary sinuses were made into one cavity. The posterior wall and mucosa of the frontal sinus were removed (Onishi et al., 1989). The dural defect resulting from the resection of the invasive tumor was reconstructed with a sheet of lyophilized dura. The supra-orbital bar was replaced and fixed in its original position with a 2~0 absorbable monofilament suture. When the skull base was widely resected, it was
INTRODUCTION Skull base defects resulting from the resection of a cranial base tumor are commonly reconstructed with an iliac bone graft or a skull outer table graft. This is combined with either a pericranial flap or a temporoparietal fascia flap to cover both the nasal and cranial surfaces of the bone graft. However, this method Js highly invasive and time-consuming and increases the likelihood of postoperative infection with consequent resorption of the bone graft. We used a hydroxyapatite-tricalciumphosphate (HAP-TCP) composite (Ceratitee; N G K Spark Plag Co. Ltd., Aichi, Japan) (Nishiyama et al. 1994) as a bone substitute to cover the skull base defect after a water-tight closure of the dural defect with a pericranial flap. Full epithelialization of the nasal surface of the Ceratite ® block was seen 6 months after the operation, even though it had been left uncovered. The method described is less invasive than conventional approaches and enables the secure reconstruction of the skull base.
SURGICAL TECHNIQUE The basic principles of cranial base surgery are: tumor resection through a craniofacial approach; reconstruction of the dura mater and repair of the bone defect with various materials and flaps; and the separation of the sinonasal cavity from the epidural space. The facial approach is seldom needed as the transcranial approach can provide a wide operative field. The approach we used was as follows: the scalp was dissected supra-periosteally through a coronal in-
Fig. 1 - Schematic drawing of the craniotomy showing the removal of the supraorbital bar. 64
Anterior cranial base reconstruction using a hydroxyapatite-tricalciumphosphate composite (Ceratite ~) as a bone substitute
~
pericrani~/~.,~ scalfpl a p ~
65
duramater
lyophi,izdura ed
Fig. 2 - A schema of a saginal section showing the layers used to reconstruct the skull base defect.
replaced with Ceratite ®. The cranial surface of the Ceratite ® block was covered by the previously elevated pericranial flap to ensure the complete separation of the cranial and the nasopharyngeal cavities. The nasal surface of the Ceratite ® was left uncovered (Fig. 2). We have used this approach in seven anterior skull base reconstructions since September 1992, and we have not encountered any intracranial complications to date.
CASE R E P O R T
Fig. 4 - Pre- and postoperative M R I of the patient (above, below).
A 66-year-old man presented with nasal obstruction and exophthalmos (Fig. 3). Magnetic resonance imaging (MRI) and computed tomographic (CT) angiography revealed a large tumor occupying both
Fig. 5 - The preoperative 3D angiogram showing vascular rich tumor.
Fig. 3 - Preoperative view of the patient.
nasal cavities. It extended to include the medial orbital wall of both eyes, the maxillary, sphenoidal and frontal sinuses and penetrated the anterior skull base to involve the anterior cerebral cortex (Figs 4 & 5). A transcranial approach was used to remove the tumor which left a 3.5 cm x 6 cm bone defect (Fig. 6). This was repaired intraoperatively with a Ceratite * block trimmed to fill the space (Fig. 7). The patient's postoperative course was uneventful with no sign of infection (Figs 8 and 9) and his exophthalmos and nasal obstruction disappeared. The histology of the tumor showed a poorly differentiated adeno-
66
Journal of Cranio Maxillo-Facial Surgery
The skull base defect resulting from the total resection of the tumor.
Fig. 6 -
Fig. 9 - Six months postoperative view of the patient. DISCUSSION
The defect was filled with a piece of Ceratite®. The dural defect was covered by a piece of lyophilized dura. A pericranial flap was turned to cover the Ceratite®block.
Fig. 7 -
Fig. 8 - Postoperative 3 dimensional CT showing the Ceratite® block in place. carcinoma. An endoscopic examination 6 months after the procedure showed that the nasal surface of the Ceratite ® block was fully covered by a mucosalike tissue. No sign of t u m o r re-growth has been seen to date (1.5 years since the operation).
Controversy exists over the use of bone substitute in the reconstruction of an anterior skull base defect (Goffin et al., 1991). Ousterbout and Tessier (1981) reported reconstruction of cribriform defects with a forehead flap. It is our opinion that a bone defect larger than 3 cm in diameter requires a bone substitute to prevent brain herniation. This should be combined with the formation of a secure barrier between the cranial and sinonasal cavities with flaps. There have been m a n y reports of the use of supportive hard materials to substitute for bone removed from the skull. These have included the use of an iliac homograft (Bebear et al., 1992) synthetic resin plate (del Pinal et al., 1989), iliac bone (Arita et al., 1989), split rib, and inner or outer table of the skull (Jackson and Marsh, 1983; Schuller et al., 1984; Yoshimura et al., 1990). M a n y authors have advocated flap coverage of not only the cranial surface but also the nasal surface to ensure the survival of the grafted bone (Schuller et al., 1984; Kiyokawa et al., 1991). In addition, some authors add a split skin graft to the nasal surface of the flap (Price et al., 1988; Kiyokawa et al., 1991). However, Arita et al. (1989) reported no problem with leaving the surface of the grafted bone exposed to the nasal cavity. We are in agreement with this, as long as secure sealing of the epidural space is achieved with a pericranial flap. Furthermore, postoperative resorption, which commonly occurs with an autogenous bone graft, does not occur with Ceratite ®. Porous Ceratite ~, has a porosity of 35 % and is 2.5 times stronger than conventional porous hydroxyapatite ceramics (Nishiyama et al., 1992). It is also biocompatible and does not cause a foreign body reaction in humans. Although its pore size (5-15 ¢tm)
Anterior cranial base reconstruction using a hydroxyapatite-tricalciumphosphatecomposite (Ceratite~) as a bone substitute does n o t allow i n g r o w t h o f b o n e into C e r a t i t e ®, it is possible for epithelial cells to o v e r g r o w its surface w h e n it is e x p o s e d to the p a r a n a s a l cavity. I n cases o f m a x i l l o f a c i a l r e c o n s t r u c t i o n we have e x p e r i e n c e d the r a p i d c o v e r a g e o f m u c o s a achieved in the m a x i l l a r y sinuses w i t h o u t infection ( N i s h i y a m a et al., 1994). I n fact, b y n a s a l e n d o s c o p y , we c o n f i r m e d t h a t the C e r a t i t e ® was fully c o v e r e d b y m u c o s a - l i k e tissue, t h o u g h we d i d n o t c o n f i r m h i s t o l o g i c a l l y w h e t h e r it was real m u c o s a o r m e r e l y fibrosis. H o w e v e r , even w h e n it c a n n o t be epithelialized, C e r a t i t e ® p l a c e d with a d e q u a t e d r a i n a g e m a y n o t l e a d to infection. I n o u r cases, the e t h m o i d a l sinuses were w i d e l y resected so t h a t the c r a n i a l base was directly o p e n e d into the n a s a l cavity. W e h a v e n o t e x p e r i e n c e d p o s t o p e r a t i v e i n t r a c r a n i a l infection in all seven p a t i e n t s t r e a t e d in the p a s t 3 years. CONCLUSIONS W e u s e d C e r a t i t e ~ as a b o n e substitute to r e c o n s t r u c t the skull base defect resulting f r o m the c u r a t i v e resection o f a t u m o r w h i c h h a d i n v a d e d the a n t e r i o r c r a n i a l fossa. T h e n a s a l surface o f the C e r a t i t e ® b l o c k was n o t c o v e r e d b y a n y flap, b u t e p i t h e l i a l i z a t i o n o f the e x p o s e d surface was c o m p l e t e within 6 m o n t h s p o s t o p e r a t i v e l y . Skull base surgery has m a d e g r e a t p r o g r e s s in the t r e a t m e n t o f p r e v i o u s l y i n o p e r a b l e invasive t u m o r s ; h o w e v e r the c o n v e n t i o n a l m e t h o d s for r e c o n s t r u c t i o n are generally invasive a n d timec o n s u m i n g . T h e m e t h o d we have d e s c r i b e d is far less invasive a n d is safe e n o u g h to offer p a t i e n t s a g o o d q u a l i t y o f life p o s t o p e r a t i v e l y . References Arita, N., S. Mori, M. Sano, T. Hayakawa, K. Nakao, N. Kanai, H. Mogami: Surgical treatment of tumors in the anterior skull
base using the transbasal approach. Neurosurgery 24 (1989) 379-384
67
Bebear, J. P., V. Darrouzet, D. Stoll: Surgery of the anterior
skull base: Total ethmoidectomy for malignant ethmoidal tumors. Israel J. Med. Sci. 28 (1992) 169-172 del Pi~al F., C. Villarreal, R. Fonseca: One stage methyl methacrylate cranioplasty in a case of frontal sinus communication--a further application of the galea frontalis myofascial flap. Eur. J. Plast. Surg. 12 (1989) 269-277 Goffin, J., E. Fossion, Ch. Plets, M. Mommaerts, L. Vrielinck:
Craniofacial resection for anterior skull base tumors. Acta Neurochirurgia. 110 (1991) 3337 Jackson, L T., W. R. Marsh: Anterior cranial fossa tumors. Ann. Plast. Surg. 11 (1983) 479489 Kiyokawa, K., I1. Tai, M. Hirano, M. Shigemori, K. Sato, S. Tanaka, Y. Inoue: A reliable primary reconstruction of the
cranial base after the resection of head and neck tumors. Jap. J. Plast. Reconstr. Surg. 34 (1991) 347 354 (English abstract) Nishiyama, T., T. Nakajima, K. Onishi, Y. Okamoto, K. Shibata:
Application of hydroxyapatite-tricalciumphosphatebone substitute for craniomaxillofacial region. Prog. Med. 12 (1992) 278~79 (Japanese) Nishiyama, T., T. Nakajima, Y. Yoshimura, 11. Nakanishi:
Utilising solid models for preoperative shaping of HAP-TCP ceramic bone substitute: application for craniomaxillofacial Surgery. Eur. J. Plast. Surg. 17 (1994) 173 177 Onishi, K., T. Nakajima, Y. Yoshimura: Treatment and therapeutic devices in the management of frontal sinus fracture. J. Craniomaxillofac. Surg. 17 (1989) 58-63 Ousterbout, d. K., P. Tessier : Closure of large cribriform defects with a forehead flap. J. Maxillofac. Surg. 9 (1981) 7-9 Price, J., M. Loury, B. Carson, M. E. Johns: The pericranial flap for reconstruction of anterior skull base defects. Laryngoscope. 98 (1988) 1159-1164 Schuller, D. E., J. H. Goodman, C. A. Miller: Reconstruction of the skull base. Laryngoscope. 94 (1984) 1359-1369 Yoshimura, Y., T. Nakajima, K. Onishi : Instrument for harvesting the outer table of the skull. J. Craniomaxillofac. Surg. 18 (1990) 179-181
Prof. Tatsuo Nakajima, MD
Department of Plastic and Reconstructive Surgery School of Medicine Fujita Health University, 1 98 Dengakngakubo, Kutsukake, Toyoake Aichi 470-11 JAPAN Paper received 15 April 1994 Accepted 10 November 1994
1Department of Plastic and Reconstructive Surgery (Head: Prof. T. Nakajima), 2Department of Neurosurgery (Head: Prof. 7". Kanno), School of Medicine, Fujita Health University, Japan
S U M M A R Y . The craniofacial approach to cranial base tumors has widened the operability of tumors with intracranial invasion. However, the resulting skull base defect must be reconstructed adequately to prevent postoperative morbidity and mortality. We use hydroxyapatite-tricalciumphosphate ceramic (Ceratite ®) as a bone substitute material to reconstruct the skull base defect in combination with the pericranial flap, ensuring separation between the sinonasal cavity and epidural cavity. Although the nasal surface of the Ceratite ® block is left exposed directly to the sinonasal cavity, it was shown to be epithelialized within 6 months postoperatively. Our method is less invasive than any other conventional method and may offer more chance of curative resection of tumors with anterior skull base invasion.
cision, then a pericranial flap was elevated and draped over the scalp flap for later use. A bifrontal osteoplastic craniotomy was performed and a supraorbital bar of bone was removed to widen the operative field (Fig. 1). Then a wide resection of the tumor was commenced. Any tumor invading the sphenoid or ethmoid sinuses, or into the orbit or nasal cavity was resected. Paranasal cavities which showed inflammatory change were drained. Hypertrophic mucosa, the nasal septum and conchae were removed when they were encroaching into the operative field. The nasal, ethmoidal, and maxillary sinuses were made into one cavity. The posterior wall and mucosa of the frontal sinus were removed (Onishi et al., 1989). The dural defect resulting from the resection of the invasive tumor was reconstructed with a sheet of lyophilized dura. The supra-orbital bar was replaced and fixed in its original position with a 2~0 absorbable monofilament suture. When the skull base was widely resected, it was
INTRODUCTION Skull base defects resulting from the resection of a cranial base tumor are commonly reconstructed with an iliac bone graft or a skull outer table graft. This is combined with either a pericranial flap or a temporoparietal fascia flap to cover both the nasal and cranial surfaces of the bone graft. However, this method Js highly invasive and time-consuming and increases the likelihood of postoperative infection with consequent resorption of the bone graft. We used a hydroxyapatite-tricalciumphosphate (HAP-TCP) composite (Ceratitee; N G K Spark Plag Co. Ltd., Aichi, Japan) (Nishiyama et al. 1994) as a bone substitute to cover the skull base defect after a water-tight closure of the dural defect with a pericranial flap. Full epithelialization of the nasal surface of the Ceratite ® block was seen 6 months after the operation, even though it had been left uncovered. The method described is less invasive than conventional approaches and enables the secure reconstruction of the skull base.
SURGICAL TECHNIQUE The basic principles of cranial base surgery are: tumor resection through a craniofacial approach; reconstruction of the dura mater and repair of the bone defect with various materials and flaps; and the separation of the sinonasal cavity from the epidural space. The facial approach is seldom needed as the transcranial approach can provide a wide operative field. The approach we used was as follows: the scalp was dissected supra-periosteally through a coronal in-
Fig. 1 - Schematic drawing of the craniotomy showing the removal of the supraorbital bar. 64
Anterior cranial base reconstruction using a hydroxyapatite-tricalciumphosphate composite (Ceratite ~) as a bone substitute
~
pericrani~/~.,~ scalfpl a p ~
65
duramater
lyophi,izdura ed
Fig. 2 - A schema of a saginal section showing the layers used to reconstruct the skull base defect.
replaced with Ceratite ®. The cranial surface of the Ceratite ® block was covered by the previously elevated pericranial flap to ensure the complete separation of the cranial and the nasopharyngeal cavities. The nasal surface of the Ceratite ® was left uncovered (Fig. 2). We have used this approach in seven anterior skull base reconstructions since September 1992, and we have not encountered any intracranial complications to date.
CASE R E P O R T
Fig. 4 - Pre- and postoperative M R I of the patient (above, below).
A 66-year-old man presented with nasal obstruction and exophthalmos (Fig. 3). Magnetic resonance imaging (MRI) and computed tomographic (CT) angiography revealed a large tumor occupying both
Fig. 5 - The preoperative 3D angiogram showing vascular rich tumor.
Fig. 3 - Preoperative view of the patient.
nasal cavities. It extended to include the medial orbital wall of both eyes, the maxillary, sphenoidal and frontal sinuses and penetrated the anterior skull base to involve the anterior cerebral cortex (Figs 4 & 5). A transcranial approach was used to remove the tumor which left a 3.5 cm x 6 cm bone defect (Fig. 6). This was repaired intraoperatively with a Ceratite * block trimmed to fill the space (Fig. 7). The patient's postoperative course was uneventful with no sign of infection (Figs 8 and 9) and his exophthalmos and nasal obstruction disappeared. The histology of the tumor showed a poorly differentiated adeno-
66
Journal of Cranio Maxillo-Facial Surgery
The skull base defect resulting from the total resection of the tumor.
Fig. 6 -
Fig. 9 - Six months postoperative view of the patient. DISCUSSION
The defect was filled with a piece of Ceratite®. The dural defect was covered by a piece of lyophilized dura. A pericranial flap was turned to cover the Ceratite®block.
Fig. 7 -
Fig. 8 - Postoperative 3 dimensional CT showing the Ceratite® block in place. carcinoma. An endoscopic examination 6 months after the procedure showed that the nasal surface of the Ceratite ® block was fully covered by a mucosalike tissue. No sign of t u m o r re-growth has been seen to date (1.5 years since the operation).
Controversy exists over the use of bone substitute in the reconstruction of an anterior skull base defect (Goffin et al., 1991). Ousterbout and Tessier (1981) reported reconstruction of cribriform defects with a forehead flap. It is our opinion that a bone defect larger than 3 cm in diameter requires a bone substitute to prevent brain herniation. This should be combined with the formation of a secure barrier between the cranial and sinonasal cavities with flaps. There have been m a n y reports of the use of supportive hard materials to substitute for bone removed from the skull. These have included the use of an iliac homograft (Bebear et al., 1992) synthetic resin plate (del Pinal et al., 1989), iliac bone (Arita et al., 1989), split rib, and inner or outer table of the skull (Jackson and Marsh, 1983; Schuller et al., 1984; Yoshimura et al., 1990). M a n y authors have advocated flap coverage of not only the cranial surface but also the nasal surface to ensure the survival of the grafted bone (Schuller et al., 1984; Kiyokawa et al., 1991). In addition, some authors add a split skin graft to the nasal surface of the flap (Price et al., 1988; Kiyokawa et al., 1991). However, Arita et al. (1989) reported no problem with leaving the surface of the grafted bone exposed to the nasal cavity. We are in agreement with this, as long as secure sealing of the epidural space is achieved with a pericranial flap. Furthermore, postoperative resorption, which commonly occurs with an autogenous bone graft, does not occur with Ceratite ®. Porous Ceratite ~, has a porosity of 35 % and is 2.5 times stronger than conventional porous hydroxyapatite ceramics (Nishiyama et al., 1992). It is also biocompatible and does not cause a foreign body reaction in humans. Although its pore size (5-15 ¢tm)
Anterior cranial base reconstruction using a hydroxyapatite-tricalciumphosphatecomposite (Ceratite~) as a bone substitute does n o t allow i n g r o w t h o f b o n e into C e r a t i t e ®, it is possible for epithelial cells to o v e r g r o w its surface w h e n it is e x p o s e d to the p a r a n a s a l cavity. I n cases o f m a x i l l o f a c i a l r e c o n s t r u c t i o n we have e x p e r i e n c e d the r a p i d c o v e r a g e o f m u c o s a achieved in the m a x i l l a r y sinuses w i t h o u t infection ( N i s h i y a m a et al., 1994). I n fact, b y n a s a l e n d o s c o p y , we c o n f i r m e d t h a t the C e r a t i t e ® was fully c o v e r e d b y m u c o s a - l i k e tissue, t h o u g h we d i d n o t c o n f i r m h i s t o l o g i c a l l y w h e t h e r it was real m u c o s a o r m e r e l y fibrosis. H o w e v e r , even w h e n it c a n n o t be epithelialized, C e r a t i t e ® p l a c e d with a d e q u a t e d r a i n a g e m a y n o t l e a d to infection. I n o u r cases, the e t h m o i d a l sinuses were w i d e l y resected so t h a t the c r a n i a l base was directly o p e n e d into the n a s a l cavity. W e h a v e n o t e x p e r i e n c e d p o s t o p e r a t i v e i n t r a c r a n i a l infection in all seven p a t i e n t s t r e a t e d in the p a s t 3 years. CONCLUSIONS W e u s e d C e r a t i t e ~ as a b o n e substitute to r e c o n s t r u c t the skull base defect resulting f r o m the c u r a t i v e resection o f a t u m o r w h i c h h a d i n v a d e d the a n t e r i o r c r a n i a l fossa. T h e n a s a l surface o f the C e r a t i t e ® b l o c k was n o t c o v e r e d b y a n y flap, b u t e p i t h e l i a l i z a t i o n o f the e x p o s e d surface was c o m p l e t e within 6 m o n t h s p o s t o p e r a t i v e l y . Skull base surgery has m a d e g r e a t p r o g r e s s in the t r e a t m e n t o f p r e v i o u s l y i n o p e r a b l e invasive t u m o r s ; h o w e v e r the c o n v e n t i o n a l m e t h o d s for r e c o n s t r u c t i o n are generally invasive a n d timec o n s u m i n g . T h e m e t h o d we have d e s c r i b e d is far less invasive a n d is safe e n o u g h to offer p a t i e n t s a g o o d q u a l i t y o f life p o s t o p e r a t i v e l y . References Arita, N., S. Mori, M. Sano, T. Hayakawa, K. Nakao, N. Kanai, H. Mogami: Surgical treatment of tumors in the anterior skull
base using the transbasal approach. Neurosurgery 24 (1989) 379-384
67
Bebear, J. P., V. Darrouzet, D. Stoll: Surgery of the anterior
skull base: Total ethmoidectomy for malignant ethmoidal tumors. Israel J. Med. Sci. 28 (1992) 169-172 del Pi~al F., C. Villarreal, R. Fonseca: One stage methyl methacrylate cranioplasty in a case of frontal sinus communication--a further application of the galea frontalis myofascial flap. Eur. J. Plast. Surg. 12 (1989) 269-277 Goffin, J., E. Fossion, Ch. Plets, M. Mommaerts, L. Vrielinck:
Craniofacial resection for anterior skull base tumors. Acta Neurochirurgia. 110 (1991) 3337 Jackson, L T., W. R. Marsh: Anterior cranial fossa tumors. Ann. Plast. Surg. 11 (1983) 479489 Kiyokawa, K., I1. Tai, M. Hirano, M. Shigemori, K. Sato, S. Tanaka, Y. Inoue: A reliable primary reconstruction of the
cranial base after the resection of head and neck tumors. Jap. J. Plast. Reconstr. Surg. 34 (1991) 347 354 (English abstract) Nishiyama, T., T. Nakajima, K. Onishi, Y. Okamoto, K. Shibata:
Application of hydroxyapatite-tricalciumphosphatebone substitute for craniomaxillofacial region. Prog. Med. 12 (1992) 278~79 (Japanese) Nishiyama, T., T. Nakajima, Y. Yoshimura, 11. Nakanishi:
Utilising solid models for preoperative shaping of HAP-TCP ceramic bone substitute: application for craniomaxillofacial Surgery. Eur. J. Plast. Surg. 17 (1994) 173 177 Onishi, K., T. Nakajima, Y. Yoshimura: Treatment and therapeutic devices in the management of frontal sinus fracture. J. Craniomaxillofac. Surg. 17 (1989) 58-63 Ousterbout, d. K., P. Tessier : Closure of large cribriform defects with a forehead flap. J. Maxillofac. Surg. 9 (1981) 7-9 Price, J., M. Loury, B. Carson, M. E. Johns: The pericranial flap for reconstruction of anterior skull base defects. Laryngoscope. 98 (1988) 1159-1164 Schuller, D. E., J. H. Goodman, C. A. Miller: Reconstruction of the skull base. Laryngoscope. 94 (1984) 1359-1369 Yoshimura, Y., T. Nakajima, K. Onishi : Instrument for harvesting the outer table of the skull. J. Craniomaxillofac. Surg. 18 (1990) 179-181
Prof. Tatsuo Nakajima, MD
Department of Plastic and Reconstructive Surgery School of Medicine Fujita Health University, 1 98 Dengakngakubo, Kutsukake, Toyoake Aichi 470-11 JAPAN Paper received 15 April 1994 Accepted 10 November 1994