J
Oral Maxillofac Surg
50:1249-l
245,1992
Treatment of an Infected Mandibular Graft Using Tobramycin-Impregnated Methylmethacrylate Beads: Report of a Case ERIC J. DIERKS,
DMD, MD,* AND BRYCE
Immediate osseous reconstruction following segmental mandibulectomy for benign neoplasms is reasonable if an adequate soft-tissue bed and oral mucosal seal can be maintained or reestablished at the time of ablative surgery. Should postoperative infection develop, debridement of the graft is usually followed by collapse and contracture of the soft-tissue bed, and subsequent attempts at reconstruction are generally delayed and must deal with deficits of both bone and soft tissue. A case is presented in which tobramycinimpregnated beads were used to salvage part of a grafted mandible and to maintain a sterile dead space in anticipation of prompt regrafting.
E. POTTER,
DMD, MDT
FIGURE 1. Panoramic radiograph showing a radiolucency of the right mandibular angle, ascending ramus, and posterior mandibular body.
Report of Case
This dosage is sufficient to eradicate any residual tumor and render the bone nonviable. The irradiated bone was then reshaped with a rotary bur to create a thin-walled, resorbable tray to contain bone-graft material. The vertical dimension of the posterior body region was also reduced to facilitate a tension-free mucosal closure. A mixed corticocancellous graft was obtained from the right posterior iliac crest and packed into the bone tray. Following a tension-free and watertight closure of the oral mucosa, the bone tray containing the graft material was replaced in its anatomic position and fixed with multiple titanium miniplates; maxillomandibular fixation (MMF) was applied. Perioperative clindamycin was given intravenously and was continued orally for 10 days following surgery, and a regimen of chlorhexidene mouth-rinsing was instituted. A postoperative panoramic radiograph showed excellent alignment of the tray and graft (Fig 2). The final pathology report confirmed the diagnosis of ameloblastoma and indicated that the margins were negative. By the third postoperative week, a dehiscence of the mucosal closure over the alveolar ridge was identified, and oral penicillin V 500 mg four times daily was begun and chlorhexidene rinses were reinstituted. Healing was otherwise satisfactory, and MMF was released after 6 weeks. During the eleventh postoperative week, spontaneous drainage of foulsmelling pus was noted near the inferior border of the graft. Antibiotic therapy consisting of clindamycin 300 mg four times daily was instituted, and subsequent culture of the drainage revealed only light growth of coagulase-negative staphylococci. Within 4 weeks, clinical mobility of the graft
An otherwise healthy, 36-year-old white man was referred with an asymptomatic multilocular radiolucency of the right posterior mandibular body and ascending ramus associated with an impacted and displaced third molar (Fig 1). The results of history and physical examination were noncontributory. A transoral biopsy led to a diagnosis of ameloblastoma. Therefore, through a combined cervical and transoral approach, an extraperiosteal right segmental mandibulectomy was performed from approximately the mandibular foramen to the ipsilateral mental foramen. Following orientation of the margins, the soft-tissue tumor was grossly curetted from the specimen and placed in formalin. The bone was then placed in a sterile saline solution within a plastic bag and sent to radiation oncology, where it was subjected to 70 cGy of external-beam radiation therapy in one 30-minute dose.
* Clinical AssociateProfessor,Oral and MaxillofaciafSurgery,Oregon Health Sciences University; Chairman, Department of Head and Neck Surgery, Emanuel Hospital, Portland, OR. 7 Clinical AssociateProfessor,Oral and Maxillofacial Surgery, Oregon Health Sciences University; Director, Maxillofaciaf Trauma, Emanuel Hospital, Portland, OR. Address correspondence to Dr Die&x Head and Neck Surgical Associates, 1849 NW Keamey #300, Portland, OR 97209. (Reprints not available.) 0 1992 American Association of Oral and Maxiilofacial Surgeons 0278-2391/92/5011-022A$3.00/0
1243
TOBRAMYCIN-IMPREGNATED
BEADS
FIGURE 7. Radiograph showing irradiated bone tray filled with autogenous corticocancellous graft returned to its original position and fixed with multiple titanium miniplates.
was present proximal
and radiographs demonstrated rotation of the fragment. Sixteen weeks after the original surgery,
complete breakdown of the graft was evident (Fig 3). Arch bars were reapplied and MMF was reinstituted. A repeated culture grew moderate Eikenella corrodens and a B-lactamase-negative Bacteroides sp; oral clindamycin therapy was resumed. Three weeks later, a transoral incision and drainage was performed under local anesthesia and several small sequestra were removed. Subsequently, the intraoral dehiscence closed
FIGURE 4. Tobramycin-impregnated before wound implantation.
methylmethacrylate
beads
and no orocutaneous fistula was noted by methylene blue testing. Probing of the submandibular drainage tract produced direct contact with the inferior mandibular border. Cultures at this time grew coagulase-negative staphylococci and peptostreptococci. Approximately weeks later (6 months after the initial surgery), the patient was returned to the operating room and the right cervical incision was reopened. A large sequestrum was identified, which corresponded to the buccal plate of the bony tray plus a portion of the adjacent corticocancellous graft. Hardware removal allowed easy delivery of the sequestrum. which left a significant dead space. The lingual plate of the tray and the adjacent graft material appeared to have partially consolidated, although a nonunion void of approximately 1.5 cm was noted. Purulence was present, and culture of the wound grew rare Eikenella corrodens. but there was no growth on anaerobic culture. On a separate sterile table, a no. 2 silk suture was threaded through two 16-F red rubber catheters with the aid of suction. A watery methylmethact-ylate mixture (Cranioplast) was made, to which 1.2 g tobramycin powder was added; the mixture was then quickly injected into the catheters. While the mixture was in a plastic state, a series of hemostats was
applied to each red rubber catheter at intervals of approximately I cm to create individual beads. Once the mixture had cured, the hemostats were removed, each catheter was longitudinally sliced. and the string of beads was removed (Fig 4). The dead space surrounding the nonunion site was irrigated and packed with the beads (Fig 5). Routine wound closure was performed, and a suction drain was placed in the subcutaneous layer. Following drain removal 2 days later, a modest amount of serosanguinous drainage was noted. This drainage became watery and ceased within 5 days. resulting in complete sealing of the wound. Five weeks after placement of the beads, the patient was returned to the operating room. Through the previous cervical incision, the bead-filled space was readily exposed and the beads were removed, revealing a healthy, well-formed pocket. A block graft, including the medial cortex and a thick layer
FIGURE 3. Radiograph showing destruction of the graft and adjacent mandible.
FIGURE 5. Soft-tissue pocket following sequestrectomy, filled with tobmmycin-impregnated beads.
1245
FKXJRE 6.
Radiograph of regrafkd mandible.
of adjacent marrow, was obtained from the right anterior iliac crest, tailored to fit the defect, and fixed to the healthy proximal and distal elements with multiple, 2.0-mm-diameter, titanium lag screws (Fig 6). No attempt was made to correct the rotation of the proximal fragment. A superiorly based platysma flap was then elevated and inset in order to wrap the lateral aspect of the graft, and a suction drain was placed in the subcutaneous plane before skin closure.
Uneventful healing ensued and no drainage persisted after drain removal. Postoperative edema rapidly resolved, and the patient was pain-free. MMF was released after 6 weeks, at which time clinical union was evident. Interincisal opening rapidly improved to 41 mm. The patient was evaluated for 4 months, and then he moved out of state.
Discussion The potential for the development of complications is present with any surgical procedure; however, the management of this patient’s original reconstruction can be justifiably criticized on several points. Had a longer proximal fragment been available for screw fixation, a mandibular reconstruction plate would have afforded greater rigidity. Ipsilateral coronoidectomy also might have resulted in greater stability at the hostgraft interface, perhaps at the expense of some degree of ultimate function. The use of a microvascular graft from the iliac crest or fibula might have proved more resistant to infection, at the cost of a much longer operation, a significant donor-site defect, and a less natural mandibular contour. Given this patient’s problem of refractory infection of the grafted mandible, and the presence of a large sequestrum, initial conventional management could have included hospitalization and high-dose parenteral antibiotics. Adjunctive hyperbaric oxygen therapy also
could have been an option. Subsequent debridement of the sequestrum would have allowed collapse and contracture of the adjacent soft tissues, and the result before regrafting would have been a scarred and contracted soft-tissue bed that might have required softtissue augmentation prior to secondary bone-graft placement. The implantation of antibiotic-impregnated methylmethacrylate has been used in orthopedic surgery for treatment of refractory osteomyelitis of the appendicular skeleton,’ and has been reported in the treatment of mandibular osteomyelitis.2,3 Acrylic cement beads have been shown not to have antimicrobial properties of their own, but will release a variety of antibiotics in a microbiologically active fonn4 A continuous release of gentamycin from such beads for more than 5 years has been observed.’ The leaching characteristics of gentamycin-impregnated polymethylmethacrylate beads in the maxillofacial region of dogs has shown extremely high antibiotic levels in the wound, with negligible serum levels.6 The use of tobramycin-impregnated methylmethacrylate beads allowed simultaneous treatment of the infection within the remaining viable bone and maintenance of the adjacent soft-tissue bulk and contour surrounding the dead space created by sequestrectomy. This case illustrates the application of existing orthopedic technology not only for treatment of the infection, but also for preservation of critical space at the infection site that would be needed for subsequent grafting. References 1. Klemm K: Posttraumattische osteomyelitis: Temporare implantation von SeptopalR-Ketten zur erganzenden lokalantibiotischen behandlung. Dtsch Ameblatt 39228 1, 1970 2. Grime PD, Bowerman JE, Weller PJ: Gentamycin impregnated polymethylmethacrylate (PMMA) beads in the treatment of primary chronic osteomyelitis of the mandible. Br J Oral Maxillofac Surg 28:367, 1990 3. Ludwig VH, Haneke A: Ein neues verfahren in der behandlung der osteomyelitis. Dtsch Z Mund Kiefer Gesichts Chir 2: 190,192. 1978 4. Marks KE, Nelson CL, Lautenschlager EP: Antibiotic-impregnated acrylic bone cement. J Bone Joint Surg 58:A:358, 1976 5. Wahlig H, Dingeldein E: Antibiotics and bone cements. Acta Orthop Stand 5 1:49,I980 6. Alpert B, Colosi T, von Ftaunhofer JA, et al: The in vivo behavior of gentamycin-PMMA beads in the maxillofacial region. J Oral Maxillofac Surg 47:46, 1989
Oral Maxillofac Surg
50:1249-l
245,1992
Treatment of an Infected Mandibular Graft Using Tobramycin-Impregnated Methylmethacrylate Beads: Report of a Case ERIC J. DIERKS,
DMD, MD,* AND BRYCE
Immediate osseous reconstruction following segmental mandibulectomy for benign neoplasms is reasonable if an adequate soft-tissue bed and oral mucosal seal can be maintained or reestablished at the time of ablative surgery. Should postoperative infection develop, debridement of the graft is usually followed by collapse and contracture of the soft-tissue bed, and subsequent attempts at reconstruction are generally delayed and must deal with deficits of both bone and soft tissue. A case is presented in which tobramycinimpregnated beads were used to salvage part of a grafted mandible and to maintain a sterile dead space in anticipation of prompt regrafting.
E. POTTER,
DMD, MDT
FIGURE 1. Panoramic radiograph showing a radiolucency of the right mandibular angle, ascending ramus, and posterior mandibular body.
Report of Case
This dosage is sufficient to eradicate any residual tumor and render the bone nonviable. The irradiated bone was then reshaped with a rotary bur to create a thin-walled, resorbable tray to contain bone-graft material. The vertical dimension of the posterior body region was also reduced to facilitate a tension-free mucosal closure. A mixed corticocancellous graft was obtained from the right posterior iliac crest and packed into the bone tray. Following a tension-free and watertight closure of the oral mucosa, the bone tray containing the graft material was replaced in its anatomic position and fixed with multiple titanium miniplates; maxillomandibular fixation (MMF) was applied. Perioperative clindamycin was given intravenously and was continued orally for 10 days following surgery, and a regimen of chlorhexidene mouth-rinsing was instituted. A postoperative panoramic radiograph showed excellent alignment of the tray and graft (Fig 2). The final pathology report confirmed the diagnosis of ameloblastoma and indicated that the margins were negative. By the third postoperative week, a dehiscence of the mucosal closure over the alveolar ridge was identified, and oral penicillin V 500 mg four times daily was begun and chlorhexidene rinses were reinstituted. Healing was otherwise satisfactory, and MMF was released after 6 weeks. During the eleventh postoperative week, spontaneous drainage of foulsmelling pus was noted near the inferior border of the graft. Antibiotic therapy consisting of clindamycin 300 mg four times daily was instituted, and subsequent culture of the drainage revealed only light growth of coagulase-negative staphylococci. Within 4 weeks, clinical mobility of the graft
An otherwise healthy, 36-year-old white man was referred with an asymptomatic multilocular radiolucency of the right posterior mandibular body and ascending ramus associated with an impacted and displaced third molar (Fig 1). The results of history and physical examination were noncontributory. A transoral biopsy led to a diagnosis of ameloblastoma. Therefore, through a combined cervical and transoral approach, an extraperiosteal right segmental mandibulectomy was performed from approximately the mandibular foramen to the ipsilateral mental foramen. Following orientation of the margins, the soft-tissue tumor was grossly curetted from the specimen and placed in formalin. The bone was then placed in a sterile saline solution within a plastic bag and sent to radiation oncology, where it was subjected to 70 cGy of external-beam radiation therapy in one 30-minute dose.
* Clinical AssociateProfessor,Oral and MaxillofaciafSurgery,Oregon Health Sciences University; Chairman, Department of Head and Neck Surgery, Emanuel Hospital, Portland, OR. 7 Clinical AssociateProfessor,Oral and Maxillofacial Surgery, Oregon Health Sciences University; Director, Maxillofaciaf Trauma, Emanuel Hospital, Portland, OR. Address correspondence to Dr Die&x Head and Neck Surgical Associates, 1849 NW Keamey #300, Portland, OR 97209. (Reprints not available.) 0 1992 American Association of Oral and Maxiilofacial Surgeons 0278-2391/92/5011-022A$3.00/0
1243
TOBRAMYCIN-IMPREGNATED
BEADS
FIGURE 7. Radiograph showing irradiated bone tray filled with autogenous corticocancellous graft returned to its original position and fixed with multiple titanium miniplates.
was present proximal
and radiographs demonstrated rotation of the fragment. Sixteen weeks after the original surgery,
complete breakdown of the graft was evident (Fig 3). Arch bars were reapplied and MMF was reinstituted. A repeated culture grew moderate Eikenella corrodens and a B-lactamase-negative Bacteroides sp; oral clindamycin therapy was resumed. Three weeks later, a transoral incision and drainage was performed under local anesthesia and several small sequestra were removed. Subsequently, the intraoral dehiscence closed
FIGURE 4. Tobramycin-impregnated before wound implantation.
methylmethacrylate
beads
and no orocutaneous fistula was noted by methylene blue testing. Probing of the submandibular drainage tract produced direct contact with the inferior mandibular border. Cultures at this time grew coagulase-negative staphylococci and peptostreptococci. Approximately weeks later (6 months after the initial surgery), the patient was returned to the operating room and the right cervical incision was reopened. A large sequestrum was identified, which corresponded to the buccal plate of the bony tray plus a portion of the adjacent corticocancellous graft. Hardware removal allowed easy delivery of the sequestrum. which left a significant dead space. The lingual plate of the tray and the adjacent graft material appeared to have partially consolidated, although a nonunion void of approximately 1.5 cm was noted. Purulence was present, and culture of the wound grew rare Eikenella corrodens. but there was no growth on anaerobic culture. On a separate sterile table, a no. 2 silk suture was threaded through two 16-F red rubber catheters with the aid of suction. A watery methylmethact-ylate mixture (Cranioplast) was made, to which 1.2 g tobramycin powder was added; the mixture was then quickly injected into the catheters. While the mixture was in a plastic state, a series of hemostats was
applied to each red rubber catheter at intervals of approximately I cm to create individual beads. Once the mixture had cured, the hemostats were removed, each catheter was longitudinally sliced. and the string of beads was removed (Fig 4). The dead space surrounding the nonunion site was irrigated and packed with the beads (Fig 5). Routine wound closure was performed, and a suction drain was placed in the subcutaneous layer. Following drain removal 2 days later, a modest amount of serosanguinous drainage was noted. This drainage became watery and ceased within 5 days. resulting in complete sealing of the wound. Five weeks after placement of the beads, the patient was returned to the operating room. Through the previous cervical incision, the bead-filled space was readily exposed and the beads were removed, revealing a healthy, well-formed pocket. A block graft, including the medial cortex and a thick layer
FIGURE 3. Radiograph showing destruction of the graft and adjacent mandible.
FIGURE 5. Soft-tissue pocket following sequestrectomy, filled with tobmmycin-impregnated beads.
1245
FKXJRE 6.
Radiograph of regrafkd mandible.
of adjacent marrow, was obtained from the right anterior iliac crest, tailored to fit the defect, and fixed to the healthy proximal and distal elements with multiple, 2.0-mm-diameter, titanium lag screws (Fig 6). No attempt was made to correct the rotation of the proximal fragment. A superiorly based platysma flap was then elevated and inset in order to wrap the lateral aspect of the graft, and a suction drain was placed in the subcutaneous plane before skin closure.
Uneventful healing ensued and no drainage persisted after drain removal. Postoperative edema rapidly resolved, and the patient was pain-free. MMF was released after 6 weeks, at which time clinical union was evident. Interincisal opening rapidly improved to 41 mm. The patient was evaluated for 4 months, and then he moved out of state.
Discussion The potential for the development of complications is present with any surgical procedure; however, the management of this patient’s original reconstruction can be justifiably criticized on several points. Had a longer proximal fragment been available for screw fixation, a mandibular reconstruction plate would have afforded greater rigidity. Ipsilateral coronoidectomy also might have resulted in greater stability at the hostgraft interface, perhaps at the expense of some degree of ultimate function. The use of a microvascular graft from the iliac crest or fibula might have proved more resistant to infection, at the cost of a much longer operation, a significant donor-site defect, and a less natural mandibular contour. Given this patient’s problem of refractory infection of the grafted mandible, and the presence of a large sequestrum, initial conventional management could have included hospitalization and high-dose parenteral antibiotics. Adjunctive hyperbaric oxygen therapy also
could have been an option. Subsequent debridement of the sequestrum would have allowed collapse and contracture of the adjacent soft tissues, and the result before regrafting would have been a scarred and contracted soft-tissue bed that might have required softtissue augmentation prior to secondary bone-graft placement. The implantation of antibiotic-impregnated methylmethacrylate has been used in orthopedic surgery for treatment of refractory osteomyelitis of the appendicular skeleton,’ and has been reported in the treatment of mandibular osteomyelitis.2,3 Acrylic cement beads have been shown not to have antimicrobial properties of their own, but will release a variety of antibiotics in a microbiologically active fonn4 A continuous release of gentamycin from such beads for more than 5 years has been observed.’ The leaching characteristics of gentamycin-impregnated polymethylmethacrylate beads in the maxillofacial region of dogs has shown extremely high antibiotic levels in the wound, with negligible serum levels.6 The use of tobramycin-impregnated methylmethacrylate beads allowed simultaneous treatment of the infection within the remaining viable bone and maintenance of the adjacent soft-tissue bulk and contour surrounding the dead space created by sequestrectomy. This case illustrates the application of existing orthopedic technology not only for treatment of the infection, but also for preservation of critical space at the infection site that would be needed for subsequent grafting. References 1. Klemm K: Posttraumattische osteomyelitis: Temporare implantation von SeptopalR-Ketten zur erganzenden lokalantibiotischen behandlung. Dtsch Ameblatt 39228 1, 1970 2. Grime PD, Bowerman JE, Weller PJ: Gentamycin impregnated polymethylmethacrylate (PMMA) beads in the treatment of primary chronic osteomyelitis of the mandible. Br J Oral Maxillofac Surg 28:367, 1990 3. Ludwig VH, Haneke A: Ein neues verfahren in der behandlung der osteomyelitis. Dtsch Z Mund Kiefer Gesichts Chir 2: 190,192. 1978 4. Marks KE, Nelson CL, Lautenschlager EP: Antibiotic-impregnated acrylic bone cement. J Bone Joint Surg 58:A:358, 1976 5. Wahlig H, Dingeldein E: Antibiotics and bone cements. Acta Orthop Stand 5 1:49,I980 6. Alpert B, Colosi T, von Ftaunhofer JA, et al: The in vivo behavior of gentamycin-PMMA beads in the maxillofacial region. J Oral Maxillofac Surg 47:46, 1989
