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Facial translocation approach to the skull base: The viability of translocated facial bone graft
Facial translocation approach to the skull base: The viability of translocated facial bone graft SHENG-PO HAO, MD, Taiwan, Republic of China
OBJECTIVES: A retrospective review of 56 patients who were operated through a facial translocation approach was carried out to assess the viability of the translocated facial bone segment. METHODS: Eleven patients had preoperative radiotherapy, and 26 had postoperative radiotherapy. In 14 patients the translocated bone segment was kept attached to the anterior cheek, and in 42 patients the bone segment was detached and then implanted. A vascularized flap was used to obliterate the defect in the paranasal sinuses in 15 patients. RESULTS: Twelve (21.4%) patients had devitalized bone segment and required sequestrectomy. The incidence of devitalized bone segment was higher in the patients who received postoperative radiotherapy (P = 0.04) and lower in the patients in whom the defect in the paranasal sinuses was reconstructed with a vascularized flap (P = 0.006). CONCLUSIONS: The translocated facial bone segment should be kept attached to the cheek soft tissue when possible, or the defect in the paranasal sinuses should be reconstructed with a vascularized flap. (Otolaryngol Head Neck Surg 2001;124:292-6.)
The facial translocation approach, with a temporary disassembly of the facial skeleton and reinsertion and fixation of the fragment at the end of the procedure, provides an excellent surgical exposure of the skull base to facilitate extensive resection of tumors and reliable reconstruction. Facial translocation is considered one of the best surgical approaches to the anterior and middle skull base. However, the viability of the translocated facial bone has seldom been evaluated, and the effect of radiation therapy to the translocated bone segment has not From the Department of Otolaryngology, Chang Gung Memorial Hospital and Chang Gung University. Presented at the Annual Meeting of the American Academy of Otolaryngology–Head and Neck Surgery, New Orleans, LA, September 26-29, 1999. Reprint requests: Sheng-Po Hao, MD, 14F, No. 16, Alley 4, Lane 137, Min-Sheng E. Rd. Sec. 5, Taipei, Taiwan, ROC. Copyright © 2001 by the American Academy of Otolaryngology–Head and Neck Surgery Foundation, Inc. 0194-5998/2001/$35.00 + 0 23/77/112308 doi:10.1067/mhn.2001.112308 292
been addressed systematically. A retrospective analysis of the patients who underwent facial translocation for the resection of skull base tumors was undertaken to evaluate the viability of the translocated facial bone. METHODS AND MATERIAL From July 1993 to June 1998, 60 patients with tumors of the skull base and paranasal sinuses underwent resection of the tumor by using the facial translocation approach. Four patients were excluded because of tumor recurrence or death within 6 months after surgery. The remaining 56 patients were eligible for evaluation of the viability of the translocated facial bone segment. The translocated bone segment was considered devitalized if there was evidence of grossly exposed necrotic bone or cutaneous discharging fistula. All the patients were followed up regularly in otolaryngology clinics for evaluation of the translocated bone graft and for cleansing debris from the sinonasal cavity on a monthly basis. There were 53 men and 3 women, and they ranged in age from 18 to 102 years of age, with a mean of 48.4 years. There were 38 malignant lesions and 18 benign lesions in our series. The detailed pathology spectrum is summarized in Table 1. Seventeen patients had previous surgery for their skull base lesions. Thirty-seven of 38 patients who had malignant tumors received radiotherapy. One patient who had an acinic cell tumor did not receive radiotherapy. Eleven patients had undergone previous curative radiotherapy, but the tumor recurred, and the patients subsequently underwent salvage surgery; one patient of this group had additional postoperative radiotherapy. Another 26 patients had postoperative radiotherapy (Table 2). The facial bone was translocated according to the location of the tumor, and surgical exposure was required. The basic principles and techniques of facial translocation followed the original description made by Janecka et al.1 The naso-orbitomaxillary bone segment was translocated most frequently because most of the lesions in this series were located in the nasopharynx, sphenoid sinus, and infratemporal fossa. In 14 patients the translocated bone segment was left attached to the cheek soft tissue and thus remained partially vascularized. However, in another 42 patients the translocated bone segment was separated from the soft tissue of the cheek and was reinserted at the end of the procedure. If the patient had previous radiotherapy, we preferred to keep the translocated bone segment attached to the soft tissue of the cheek and thus remained vascularized; however, this was not always technically feasible. The same situation occurred in those patients who had previous surgery, such as lateral rhinotomy or the Caldwell-
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Table 1. Pathology of the 56 patients who underwent the facial translocation approach Benign
No.
Inverted papilloma Nasopharyngeal angiofibroma Mucocele of the frontoethmoidal sinuses Aggressive nasal polyposis Pleomorphic adenoma of the orbit Neurofibroma Total
Malignant
9 3 2 2 1 1 18
NPC Squamous cell carcinoma Olfactory Neuroblastoma Mucoepidermoid carcinoma Adenocystic carcinoma Osteogenic sarcoma Chordoma Chondrosarcoma Malignant melanoma Leiomyosarcoma Acinic cell tumor Total
No.
9 8 7 3 3 2 2 1 1 1 1 38
Table 2. Detailed data on bone graft, radiation therapy, and reconstruction and its related bone graft necrosis
Free bone graft (42)
Attached bone graft (14)
Preoperative RT (1)
Preoperative RT (10)
Postoperative RT (22)
No RT (19)
[
Reconstruction (0) BGN (0)
[
Reconstruction (9) BGN (0)
[
Reconstruction (0) BGN (0)
[
Reconstruction (4) BGN (0)
No reconstruction (1) BGN (1)
No reconstruction (13) BGN (8)
No reconstruction (19) BGN (2)
No reconstruction (6) BGN (0)
Postoperative RT (3)
[
Reconstruction (1) BGN (0) No reconstruction (2) BGN (1)
Both RT (1)
[
Reconstruction (1) BGN (0) No reconstruction (0) BGN (0)
No RT (0)
[
Reconstruction (0) BGN (0) No reconstruction (0) BGN (0)
RT, Radiation therapy; BGN, bone graft necrosis.
Luc approach. A temporalis muscle flap or a galeopericranial flap was used to reconstruct the skull base defect and separated the intracranial cavity from the upper aerodigestive tract. The defect in the paranasal sinuses was not reconstructed in 41 patients. The defect was obliterated with a vascularized soft tissue flap in 15 patients. Various flaps were used for the reconstruction of the defect in the paranasal sinuses, including regional flaps, such as the temporalis muscle flap, and free flaps, such as the rectus abdominis muscle flap or anterolateral thigh flap. The translocated facial bone segment was rein-
serted at the end of the procedure and secured with a titanium microplate or miniplate with a rigid 3-point fixation. Central and peripheral anchoring of the soft tissue to the facial bone was done in those cases with a nonvascularized bone graft. Postoperative radiotherapy started within 6 weeks after surgery and usually lasted for 2 months. The radiotherapy dosage was at least 6600 rad. Regular cleansing of the cavity in the paranasal sinuses was carried out in the clinics on a weekly basis during radiotherapy and once per month after radiotherapy. Tiny necrotic bone spicules were routinely removed in the clinics.
294 HAO
RESULTS
In the group of 42 patients with free bone graft, 19 never had radiotherapy, and 22 patients had postoperative radiotherapy. One patient had preoperative radiotherapy. Nine of the 22 patients who underwent postoperative radiotherapy had soft-tissue reconstruction of the defect in the paranasal sinuses, and none had necrosis of the bone graft. Among the other 13 patients who had no reconstruction but had postoperative radiotherapy, 8 patients had necrosis of the bone graft. The one patient who had preoperative radiotherapy later had necrosis of the bone graft. Among the 19 patients who never had radiotherapy, 2 had necrosis of the bone graft; however, one of these 2 patients had a previous lateral rhinotomy (Table 2). Statistical analysis revealed that in the group of patients with free bone graft, postoperative radiotherapy significantly increased the incidence of necrosis of the bone graft (P = 0.04, Pearson), whereas soft-tissue reconstruction of the paranasal sinuses defect significantly decreased the incidence of bone graft necrosis (P = 0.006). In the group of 14 patients with attached bone graft, 10 had preoperative radiotherapy, 3 had postoperative radiotherapy, and 1 had both preoperative and postoperative radiotherapy. Of the 3 patients who had postoperative radiotherapy, one had reconstruction of the defect in the paranasal sinuses, and he never had necrosis of the bone graft. Two patients did not have reconstruction, and one of these 2 patients had necrosis of the bone graft. Of the 10 patients who had preoperative radiotherapy, 4 had soft-tissue reconstruction of the paranasal sinuses defect, and 6 did not have reconstruction; these 10 patients did not have necrosis of the bone graft. The one patient who had both preoperative and postoperative radiotherapy also had soft tissue reconstruction, and he did not have necrosis of the bone graft (Table 2). Statistical analysis also revealed that although the incidence of necrosis of the bone graft was higher in the free bone graft group (11/42 [26.2%]) than in the attached bone graft group (1/14 [7.1%]), it was not statistically significant (P = 0.258). Overall, twelve (21.4%) patients had necrosis of the bone graft and required formal sequestrectomy in the operating room. The sequestrectomy was carried out at least 6 months after surgery or 3 months after radiotherapy. In 6 patients a free flap was transferred to obliterate the paranasal sinuses after sequestrectomy, to cover the bare bone, and sometimes to resurface the facial defect. DISCUSSION
Through the years, there have been a number of valuable surgical approaches to the middle cranial base described, including the infratemporal fossa approach,2 the preauricular infratemporal subtemporal approach,3
Otolaryngology– Head and Neck Surgery March 2001
the facial translocation approach,1 the extended osteoplastic maxillotomy approach,4 the maxillary swing approach,5 and the Le Fort osteotomy approach.6 These approaches have provided various routes and exposure for resection of a variety of tumors and reconstruction of the defect. For tumors arising from the central cranial base and extending to neighboring anatomic regions, such as the nasal cavity, paranasal sinuses, nasopharynx, sphenoid sinus and ridge, infratemporal fossa, and anterior and middle cranial fossa, the facial translocation approach can be the simplest and most direct way to expose this area and to facilitate extensive tumor removal.7 However, the facial translocation approach, by translocating the facial bone segment and then reimplanting it, has its potential pitfalls. The translocated facial bone segment becomes a free bone graft if not left attached to the soft tissue of the cheek. Unfortunately, the viability of the translocated graft has never been studied systematically. Furthermore, facial growth in children may be affected by this procedure. Theoretically, the vascularity of the translocated bone segment could be preserved if the osteotomized facial bone segment remained attached to the soft tissue of the cheek. The approach, however, might be technically difficult, especially when the anterior wall of the maxillary sinus was removed in the previous lateral rhinotomy or Caldwell-Luc surgery. The osteotomy of the lateral wall is another technical challenge. The lateral osteotomy is usually done in a blind method and may incidentally injure the internal maxillary artery. It is difficult to control the bleeding unless the translocated facial bone was removed as a free bone graft. Furthermore, nearly all cranial base malignancies necessitate postoperative radiotherapy, and radiotherapy is known to delay the normal healing process of both bone and soft tissue. Radiotherapy may cause hypovascularity, hypoxia, and hypocellularity and may delay the healing of both soft tissue and bone.8-10 This disturbed bone regeneration is postulated to be multifactorial. Specifically, bone healing after radiotherapy is retarded by damage to the bone morphogenic protein,11 connective tissue injury,12 and decreased microcirculation in the bone. The importance of rigid fixation for successful bone healing cannot be overemphasized. Bone healing can be improved if bone segments are fixed rigidly, so that revascularization can proceed without the microtrauma of continuous movement. In the facial translocation approach, the initial facial osteotomy should be carried out in an eyehole pattern, with the edges trimmed to fit exactly and held against each other before microplate fixation is commenced. The gap between the osteotomized bone segment and the remaining facial bone will be filled up with fibrous tissue, although active new bone formation
Otolaryngology– Head and Neck Surgery Volume 124 Number 3
might occur. However, this active new bone formation may also be disturbed if the microplates are mechanically unstable and retarded if postoperative radiotherapy is administered.13 Central and peripheral anchoring of the soft tissue of the cheek to the transplanted bone might further stabilize the translocated bone graft and help early revascularization. The craniofacial skeleton, with the exception of the mandible, is directly supplied by periosteal perforators and muscular attachments.14 These bones, unlike the mandible, have no intramedullary blood vessels. The infraorbital artery runs across the orbital floor, pierces through the maxilla, exits the infraorbital foramen, and forms a rich vascular network with the external facial artery over the anterior cheek. This infraorbital artery must be divided in most naso-orbitomaxillary osteotomies. Thus in the facial translocation approach, although the osteotomized facial bone segment remains vascularized by preserving the anterior cheek attachment, the blood supply of the translocated facial bone segment, which mainly derives from the facial artery, is still very redundant. If the reimplanted facial bone segment becomes a free bone graft and fails to revascularize and the patient still undergoes radiotherapy, the incidence of osteoradionecrosis is increased. This avascular bone segment can also become contaminated by bacteria from the adjacent paranasal sinus cavity and may result in a chronic infection with a discharging sinus. Under this circumstance, the devitalized bone must be radically removed, and the resulting defect reconstructed with a vascularized flap that not only brings a new blood supply and nutrients to help the healing process but also obliterates the paranasal sinuses cavity, thereby preventing further exposure of bone.15 Although our results favor the immediate reconstruction of the defect in the paranasal sinuses, the obvious risk inherent in immediate reconstruction should not be overlooked. Positive margins may be discovered some time later when permanent pathologic sections become available despite clear margins on initial frozen sections. The detection of local recurrences can be hindered by a bulky space-occupying flap, and with a delay in diagnosis, such recurrences may become inoperable. Follow-up can only be performed with CT or MRI. Even so, there are still difficulties in differentiating early recurrence from the flap. Hyperbaric oxygen therapy (HBO) might be a solution to the dilemma. Preoperative HBO is indicated in patients who have had preoperative radiotherapy because HBO might reverse the hypovascularity caused by radiotherapy.16 HBO might also be useful to those patients who will receive radiotherapy after the facial translocation procedure.
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It is also crucial to ask the patient to maintain local hygiene of the cavity in the paranasal sinuses and skull base to prevent osteoradionecrosis in the heavily radiated paranasal sinuses. Patients were instructed to irrigate the hollow cavity in the nasal and paranasal sinuses with warm saline everyday. Periodic cleansing under sinoscopy in the otolaryngology clinic is also mandatory. Some very tenacious secretions need to be cleansed, or the translocated bone segment may become infected, leading to sequestration. In this series the highest incidence of devitalized bone graft occurred in the patients with free bone graft who had either preoperative (100%) or postoperative (8/13 [61.5%]) radiotherapy. Postoperative radiotherapy significantly increased the incidence of bone graft necrosis. However, if the defect of the paranasal sinuses was reconstructed with a vascularized flap, there were no instances of bone necrosis, as compared with the 9 of 14 patients with bone graft necrosis who had either preoperative or postoperative radiotherapy without soft tissue reconstruction. It is worthwhile to note that only one patient had necrosis of the bone graft of the 14 patients in whom the bone graft remained attached. This patient also had postoperative radiotherapy but no reconstruction of the defect in the paranasal sinuses. On the basis of the solid data we obtained in this series, we conclude that the irradiation had a serious effect on the viability of the translocated facial bone segment. We suggest that the facial bone graft should be left attached to the soft tissue of the cheek whenever possible. If this cannot be done, the defect of the paranasal sinuses should be reconstructed with a vascularized flap, especially when the patient is going to have postoperative radiotherapy. However, this approach might potentially hinder the detection of local recurrences. REFERENCES 1. Janecka IP, Sen C, Sekhar, et al. Facial translocation: a new approach to the cranial base. Otolaryngol Head Neck Surg 1990;103:413-9. 2. Fisch U. Infratemporal fossa approach to tumors of the temporal bone and base of skull. J Laryngol Otol 1978;92:949-67. 3. Sekhar L, Schramm V, Jones N. Subtemporal preauricular infratemporal fossa approach to large lateral and posterior cranial base neoplasms. J Neurosurg 1987;67:488-99. 4. Catalano PJ, Biller HF. Extended osteoplastic maxillotomy: a versatile new procedure for wide access to the central skull base and infratemporal fossa. Arch Otolaryngol Head Neck Surg 1993;119:394-401. 5. Wei WI, Lam KH, Sham JST. New approach to the nasopharynx, the maxillary swing approach. Head Neck 1991;13:200-7. 6. Williams WG, Lo LJ, Chen YR. The Le Fort I-palatal split approach for skull base tumors: efficacy, complications, and outcome. Plast Reconstr Surg 1998;102:2310-9. 7. Janecka IP. Classification of facial translocation approach to the skull base. Otolaryngol Head Neck Surg 1995;112:579-85. 8. Hayashi S, Suit HD. The effect of fractionation of radiation dose on callus formation at site of fracture. Radiology 1971;101:181-3.
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9. Jacobsson M, Jonsson A, Albrektsson T, et al. Dose response for bone regeneration after single doses of Co60 irradiation. Int J Radiol Oncol Biol Phys 1986;4:105-12. 10. Pelker RR, Friedlander GE, Panjabi MM, et al. Radiationinduced alterations of fracture healing biomechanics. J Orthop Res 1984;2:90-8. 11. Urist MR, Hernandez A. Excitation transfer in bone: deleterious effects of cobalt 60 radiation sterilization of bank bone. Arch Surg 1974;109:486-93. 12. Friedenstein AJ, Latzinik NV, Gorskaya UF, et al. Radiosensitivity and post-irradiation changes of bone marrow clonogenic stromal mechanocytes. Int J Radiat Biol 1981;39:537-41.
Otolaryngology– Head and Neck Surgery March 2001
13. Kloth DW, Ganey T, Greenburg H, et al. Effects of radiation therapy on reconstruction of mandibular defects with a titanium reconstruction plate. Otolaryngol Head Neck Surg 1996; 114:620-7. 14. Sanger JR, Hatloub HS, Yousif NJ, et al. Management of osteoradionecrosis of the mandible. Clin Plast Surg 1993;20:517-30. 15. Hao SP, Chen HC, Wei FC, et al Systematic management of osteoradionecrosis in the head and neck. Laryngoscope 1999; 109:1324-7. 16. Marx RE, Ames R Jr. The use of hyperbaric oxygen therapy in bony reconstruction of the irradiated and tissue-deficient patients. J Oral Maxillofac Surg 1982;40:412-20.
OBJECTIVES: A retrospective review of 56 patients who were operated through a facial translocation approach was carried out to assess the viability of the translocated facial bone segment. METHODS: Eleven patients had preoperative radiotherapy, and 26 had postoperative radiotherapy. In 14 patients the translocated bone segment was kept attached to the anterior cheek, and in 42 patients the bone segment was detached and then implanted. A vascularized flap was used to obliterate the defect in the paranasal sinuses in 15 patients. RESULTS: Twelve (21.4%) patients had devitalized bone segment and required sequestrectomy. The incidence of devitalized bone segment was higher in the patients who received postoperative radiotherapy (P = 0.04) and lower in the patients in whom the defect in the paranasal sinuses was reconstructed with a vascularized flap (P = 0.006). CONCLUSIONS: The translocated facial bone segment should be kept attached to the cheek soft tissue when possible, or the defect in the paranasal sinuses should be reconstructed with a vascularized flap. (Otolaryngol Head Neck Surg 2001;124:292-6.)
The facial translocation approach, with a temporary disassembly of the facial skeleton and reinsertion and fixation of the fragment at the end of the procedure, provides an excellent surgical exposure of the skull base to facilitate extensive resection of tumors and reliable reconstruction. Facial translocation is considered one of the best surgical approaches to the anterior and middle skull base. However, the viability of the translocated facial bone has seldom been evaluated, and the effect of radiation therapy to the translocated bone segment has not From the Department of Otolaryngology, Chang Gung Memorial Hospital and Chang Gung University. Presented at the Annual Meeting of the American Academy of Otolaryngology–Head and Neck Surgery, New Orleans, LA, September 26-29, 1999. Reprint requests: Sheng-Po Hao, MD, 14F, No. 16, Alley 4, Lane 137, Min-Sheng E. Rd. Sec. 5, Taipei, Taiwan, ROC. Copyright © 2001 by the American Academy of Otolaryngology–Head and Neck Surgery Foundation, Inc. 0194-5998/2001/$35.00 + 0 23/77/112308 doi:10.1067/mhn.2001.112308 292
been addressed systematically. A retrospective analysis of the patients who underwent facial translocation for the resection of skull base tumors was undertaken to evaluate the viability of the translocated facial bone. METHODS AND MATERIAL From July 1993 to June 1998, 60 patients with tumors of the skull base and paranasal sinuses underwent resection of the tumor by using the facial translocation approach. Four patients were excluded because of tumor recurrence or death within 6 months after surgery. The remaining 56 patients were eligible for evaluation of the viability of the translocated facial bone segment. The translocated bone segment was considered devitalized if there was evidence of grossly exposed necrotic bone or cutaneous discharging fistula. All the patients were followed up regularly in otolaryngology clinics for evaluation of the translocated bone graft and for cleansing debris from the sinonasal cavity on a monthly basis. There were 53 men and 3 women, and they ranged in age from 18 to 102 years of age, with a mean of 48.4 years. There were 38 malignant lesions and 18 benign lesions in our series. The detailed pathology spectrum is summarized in Table 1. Seventeen patients had previous surgery for their skull base lesions. Thirty-seven of 38 patients who had malignant tumors received radiotherapy. One patient who had an acinic cell tumor did not receive radiotherapy. Eleven patients had undergone previous curative radiotherapy, but the tumor recurred, and the patients subsequently underwent salvage surgery; one patient of this group had additional postoperative radiotherapy. Another 26 patients had postoperative radiotherapy (Table 2). The facial bone was translocated according to the location of the tumor, and surgical exposure was required. The basic principles and techniques of facial translocation followed the original description made by Janecka et al.1 The naso-orbitomaxillary bone segment was translocated most frequently because most of the lesions in this series were located in the nasopharynx, sphenoid sinus, and infratemporal fossa. In 14 patients the translocated bone segment was left attached to the cheek soft tissue and thus remained partially vascularized. However, in another 42 patients the translocated bone segment was separated from the soft tissue of the cheek and was reinserted at the end of the procedure. If the patient had previous radiotherapy, we preferred to keep the translocated bone segment attached to the soft tissue of the cheek and thus remained vascularized; however, this was not always technically feasible. The same situation occurred in those patients who had previous surgery, such as lateral rhinotomy or the Caldwell-
Otolaryngology– Head and Neck Surgery Volume 124 Number 3
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Table 1. Pathology of the 56 patients who underwent the facial translocation approach Benign
No.
Inverted papilloma Nasopharyngeal angiofibroma Mucocele of the frontoethmoidal sinuses Aggressive nasal polyposis Pleomorphic adenoma of the orbit Neurofibroma Total
Malignant
9 3 2 2 1 1 18
NPC Squamous cell carcinoma Olfactory Neuroblastoma Mucoepidermoid carcinoma Adenocystic carcinoma Osteogenic sarcoma Chordoma Chondrosarcoma Malignant melanoma Leiomyosarcoma Acinic cell tumor Total
No.
9 8 7 3 3 2 2 1 1 1 1 38
Table 2. Detailed data on bone graft, radiation therapy, and reconstruction and its related bone graft necrosis
Free bone graft (42)
Attached bone graft (14)
Preoperative RT (1)
Preoperative RT (10)
Postoperative RT (22)
No RT (19)
[
Reconstruction (0) BGN (0)
[
Reconstruction (9) BGN (0)
[
Reconstruction (0) BGN (0)
[
Reconstruction (4) BGN (0)
No reconstruction (1) BGN (1)
No reconstruction (13) BGN (8)
No reconstruction (19) BGN (2)
No reconstruction (6) BGN (0)
Postoperative RT (3)
[
Reconstruction (1) BGN (0) No reconstruction (2) BGN (1)
Both RT (1)
[
Reconstruction (1) BGN (0) No reconstruction (0) BGN (0)
No RT (0)
[
Reconstruction (0) BGN (0) No reconstruction (0) BGN (0)
RT, Radiation therapy; BGN, bone graft necrosis.
Luc approach. A temporalis muscle flap or a galeopericranial flap was used to reconstruct the skull base defect and separated the intracranial cavity from the upper aerodigestive tract. The defect in the paranasal sinuses was not reconstructed in 41 patients. The defect was obliterated with a vascularized soft tissue flap in 15 patients. Various flaps were used for the reconstruction of the defect in the paranasal sinuses, including regional flaps, such as the temporalis muscle flap, and free flaps, such as the rectus abdominis muscle flap or anterolateral thigh flap. The translocated facial bone segment was rein-
serted at the end of the procedure and secured with a titanium microplate or miniplate with a rigid 3-point fixation. Central and peripheral anchoring of the soft tissue to the facial bone was done in those cases with a nonvascularized bone graft. Postoperative radiotherapy started within 6 weeks after surgery and usually lasted for 2 months. The radiotherapy dosage was at least 6600 rad. Regular cleansing of the cavity in the paranasal sinuses was carried out in the clinics on a weekly basis during radiotherapy and once per month after radiotherapy. Tiny necrotic bone spicules were routinely removed in the clinics.
294 HAO
RESULTS
In the group of 42 patients with free bone graft, 19 never had radiotherapy, and 22 patients had postoperative radiotherapy. One patient had preoperative radiotherapy. Nine of the 22 patients who underwent postoperative radiotherapy had soft-tissue reconstruction of the defect in the paranasal sinuses, and none had necrosis of the bone graft. Among the other 13 patients who had no reconstruction but had postoperative radiotherapy, 8 patients had necrosis of the bone graft. The one patient who had preoperative radiotherapy later had necrosis of the bone graft. Among the 19 patients who never had radiotherapy, 2 had necrosis of the bone graft; however, one of these 2 patients had a previous lateral rhinotomy (Table 2). Statistical analysis revealed that in the group of patients with free bone graft, postoperative radiotherapy significantly increased the incidence of necrosis of the bone graft (P = 0.04, Pearson), whereas soft-tissue reconstruction of the paranasal sinuses defect significantly decreased the incidence of bone graft necrosis (P = 0.006). In the group of 14 patients with attached bone graft, 10 had preoperative radiotherapy, 3 had postoperative radiotherapy, and 1 had both preoperative and postoperative radiotherapy. Of the 3 patients who had postoperative radiotherapy, one had reconstruction of the defect in the paranasal sinuses, and he never had necrosis of the bone graft. Two patients did not have reconstruction, and one of these 2 patients had necrosis of the bone graft. Of the 10 patients who had preoperative radiotherapy, 4 had soft-tissue reconstruction of the paranasal sinuses defect, and 6 did not have reconstruction; these 10 patients did not have necrosis of the bone graft. The one patient who had both preoperative and postoperative radiotherapy also had soft tissue reconstruction, and he did not have necrosis of the bone graft (Table 2). Statistical analysis also revealed that although the incidence of necrosis of the bone graft was higher in the free bone graft group (11/42 [26.2%]) than in the attached bone graft group (1/14 [7.1%]), it was not statistically significant (P = 0.258). Overall, twelve (21.4%) patients had necrosis of the bone graft and required formal sequestrectomy in the operating room. The sequestrectomy was carried out at least 6 months after surgery or 3 months after radiotherapy. In 6 patients a free flap was transferred to obliterate the paranasal sinuses after sequestrectomy, to cover the bare bone, and sometimes to resurface the facial defect. DISCUSSION
Through the years, there have been a number of valuable surgical approaches to the middle cranial base described, including the infratemporal fossa approach,2 the preauricular infratemporal subtemporal approach,3
Otolaryngology– Head and Neck Surgery March 2001
the facial translocation approach,1 the extended osteoplastic maxillotomy approach,4 the maxillary swing approach,5 and the Le Fort osteotomy approach.6 These approaches have provided various routes and exposure for resection of a variety of tumors and reconstruction of the defect. For tumors arising from the central cranial base and extending to neighboring anatomic regions, such as the nasal cavity, paranasal sinuses, nasopharynx, sphenoid sinus and ridge, infratemporal fossa, and anterior and middle cranial fossa, the facial translocation approach can be the simplest and most direct way to expose this area and to facilitate extensive tumor removal.7 However, the facial translocation approach, by translocating the facial bone segment and then reimplanting it, has its potential pitfalls. The translocated facial bone segment becomes a free bone graft if not left attached to the soft tissue of the cheek. Unfortunately, the viability of the translocated graft has never been studied systematically. Furthermore, facial growth in children may be affected by this procedure. Theoretically, the vascularity of the translocated bone segment could be preserved if the osteotomized facial bone segment remained attached to the soft tissue of the cheek. The approach, however, might be technically difficult, especially when the anterior wall of the maxillary sinus was removed in the previous lateral rhinotomy or Caldwell-Luc surgery. The osteotomy of the lateral wall is another technical challenge. The lateral osteotomy is usually done in a blind method and may incidentally injure the internal maxillary artery. It is difficult to control the bleeding unless the translocated facial bone was removed as a free bone graft. Furthermore, nearly all cranial base malignancies necessitate postoperative radiotherapy, and radiotherapy is known to delay the normal healing process of both bone and soft tissue. Radiotherapy may cause hypovascularity, hypoxia, and hypocellularity and may delay the healing of both soft tissue and bone.8-10 This disturbed bone regeneration is postulated to be multifactorial. Specifically, bone healing after radiotherapy is retarded by damage to the bone morphogenic protein,11 connective tissue injury,12 and decreased microcirculation in the bone. The importance of rigid fixation for successful bone healing cannot be overemphasized. Bone healing can be improved if bone segments are fixed rigidly, so that revascularization can proceed without the microtrauma of continuous movement. In the facial translocation approach, the initial facial osteotomy should be carried out in an eyehole pattern, with the edges trimmed to fit exactly and held against each other before microplate fixation is commenced. The gap between the osteotomized bone segment and the remaining facial bone will be filled up with fibrous tissue, although active new bone formation
Otolaryngology– Head and Neck Surgery Volume 124 Number 3
might occur. However, this active new bone formation may also be disturbed if the microplates are mechanically unstable and retarded if postoperative radiotherapy is administered.13 Central and peripheral anchoring of the soft tissue of the cheek to the transplanted bone might further stabilize the translocated bone graft and help early revascularization. The craniofacial skeleton, with the exception of the mandible, is directly supplied by periosteal perforators and muscular attachments.14 These bones, unlike the mandible, have no intramedullary blood vessels. The infraorbital artery runs across the orbital floor, pierces through the maxilla, exits the infraorbital foramen, and forms a rich vascular network with the external facial artery over the anterior cheek. This infraorbital artery must be divided in most naso-orbitomaxillary osteotomies. Thus in the facial translocation approach, although the osteotomized facial bone segment remains vascularized by preserving the anterior cheek attachment, the blood supply of the translocated facial bone segment, which mainly derives from the facial artery, is still very redundant. If the reimplanted facial bone segment becomes a free bone graft and fails to revascularize and the patient still undergoes radiotherapy, the incidence of osteoradionecrosis is increased. This avascular bone segment can also become contaminated by bacteria from the adjacent paranasal sinus cavity and may result in a chronic infection with a discharging sinus. Under this circumstance, the devitalized bone must be radically removed, and the resulting defect reconstructed with a vascularized flap that not only brings a new blood supply and nutrients to help the healing process but also obliterates the paranasal sinuses cavity, thereby preventing further exposure of bone.15 Although our results favor the immediate reconstruction of the defect in the paranasal sinuses, the obvious risk inherent in immediate reconstruction should not be overlooked. Positive margins may be discovered some time later when permanent pathologic sections become available despite clear margins on initial frozen sections. The detection of local recurrences can be hindered by a bulky space-occupying flap, and with a delay in diagnosis, such recurrences may become inoperable. Follow-up can only be performed with CT or MRI. Even so, there are still difficulties in differentiating early recurrence from the flap. Hyperbaric oxygen therapy (HBO) might be a solution to the dilemma. Preoperative HBO is indicated in patients who have had preoperative radiotherapy because HBO might reverse the hypovascularity caused by radiotherapy.16 HBO might also be useful to those patients who will receive radiotherapy after the facial translocation procedure.
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It is also crucial to ask the patient to maintain local hygiene of the cavity in the paranasal sinuses and skull base to prevent osteoradionecrosis in the heavily radiated paranasal sinuses. Patients were instructed to irrigate the hollow cavity in the nasal and paranasal sinuses with warm saline everyday. Periodic cleansing under sinoscopy in the otolaryngology clinic is also mandatory. Some very tenacious secretions need to be cleansed, or the translocated bone segment may become infected, leading to sequestration. In this series the highest incidence of devitalized bone graft occurred in the patients with free bone graft who had either preoperative (100%) or postoperative (8/13 [61.5%]) radiotherapy. Postoperative radiotherapy significantly increased the incidence of bone graft necrosis. However, if the defect of the paranasal sinuses was reconstructed with a vascularized flap, there were no instances of bone necrosis, as compared with the 9 of 14 patients with bone graft necrosis who had either preoperative or postoperative radiotherapy without soft tissue reconstruction. It is worthwhile to note that only one patient had necrosis of the bone graft of the 14 patients in whom the bone graft remained attached. This patient also had postoperative radiotherapy but no reconstruction of the defect in the paranasal sinuses. On the basis of the solid data we obtained in this series, we conclude that the irradiation had a serious effect on the viability of the translocated facial bone segment. We suggest that the facial bone graft should be left attached to the soft tissue of the cheek whenever possible. If this cannot be done, the defect of the paranasal sinuses should be reconstructed with a vascularized flap, especially when the patient is going to have postoperative radiotherapy. However, this approach might potentially hinder the detection of local recurrences. REFERENCES 1. Janecka IP, Sen C, Sekhar, et al. Facial translocation: a new approach to the cranial base. Otolaryngol Head Neck Surg 1990;103:413-9. 2. Fisch U. Infratemporal fossa approach to tumors of the temporal bone and base of skull. J Laryngol Otol 1978;92:949-67. 3. Sekhar L, Schramm V, Jones N. Subtemporal preauricular infratemporal fossa approach to large lateral and posterior cranial base neoplasms. J Neurosurg 1987;67:488-99. 4. Catalano PJ, Biller HF. Extended osteoplastic maxillotomy: a versatile new procedure for wide access to the central skull base and infratemporal fossa. Arch Otolaryngol Head Neck Surg 1993;119:394-401. 5. Wei WI, Lam KH, Sham JST. New approach to the nasopharynx, the maxillary swing approach. Head Neck 1991;13:200-7. 6. Williams WG, Lo LJ, Chen YR. The Le Fort I-palatal split approach for skull base tumors: efficacy, complications, and outcome. Plast Reconstr Surg 1998;102:2310-9. 7. Janecka IP. Classification of facial translocation approach to the skull base. Otolaryngol Head Neck Surg 1995;112:579-85. 8. Hayashi S, Suit HD. The effect of fractionation of radiation dose on callus formation at site of fracture. Radiology 1971;101:181-3.
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9. Jacobsson M, Jonsson A, Albrektsson T, et al. Dose response for bone regeneration after single doses of Co60 irradiation. Int J Radiol Oncol Biol Phys 1986;4:105-12. 10. Pelker RR, Friedlander GE, Panjabi MM, et al. Radiationinduced alterations of fracture healing biomechanics. J Orthop Res 1984;2:90-8. 11. Urist MR, Hernandez A. Excitation transfer in bone: deleterious effects of cobalt 60 radiation sterilization of bank bone. Arch Surg 1974;109:486-93. 12. Friedenstein AJ, Latzinik NV, Gorskaya UF, et al. Radiosensitivity and post-irradiation changes of bone marrow clonogenic stromal mechanocytes. Int J Radiat Biol 1981;39:537-41.
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13. Kloth DW, Ganey T, Greenburg H, et al. Effects of radiation therapy on reconstruction of mandibular defects with a titanium reconstruction plate. Otolaryngol Head Neck Surg 1996; 114:620-7. 14. Sanger JR, Hatloub HS, Yousif NJ, et al. Management of osteoradionecrosis of the mandible. Clin Plast Surg 1993;20:517-30. 15. Hao SP, Chen HC, Wei FC, et al Systematic management of osteoradionecrosis in the head and neck. Laryngoscope 1999; 109:1324-7. 16. Marx RE, Ames R Jr. The use of hyperbaric oxygen therapy in bony reconstruction of the irradiated and tissue-deficient patients. J Oral Maxillofac Surg 1982;40:412-20.