The Journal of Craniofacial Surgery • Volume 26, Number 1, January 2015
Brief Clinical Studies
developed. It is seen as an advantage that ketamine can be administered in different routes at analgesic dosage and has a low incidence of adverse effects. Ketamine is considered as an alternative for administration to postoperative analgesic drugs such as the opioids, nonopioids, and nonsteroidal anti-inflammatory drugs.
REFERENCES 1. McNeill RA. A history of tonsillectomy: two millenia of trauma, haemorrhage and controversy. Ulster Med J 1960;29:59–63 2. Ugur MB, Yilmaz M, Altunkaya H, et al. Effect of intramuscular and peritonsillar injection of tramadol before tonsillectomy: a double blind randomized, placebo-controlled clinical trial. Int J Pediatr Otorhinolaryngol 2008;72:241–248 3. Engelhardt T, Steel E, Johnston G, et al. Tramadol for pain relief in children undergoing tonsillectomy; a comparison with morphine. Paediatr Anaesth 2003;13:249–252 4. Dal D, Celebi N, Elvan EG, et al. The efficacy of intravenous or peritonsillar infiltration of ketamine for postoperative in children following adenotonsillectomy. Paediatr Anaesth 2007;17:263–269 5. Umuroglu T, Eti Z, Ciftci H, et al. Analgesia for adenotonsillectomy in children: a comparison of morphine, ketamine, and tramadol. Paediatr Anaesth 2004;14:568–573 6. Aydin ON, Ugur B, Ozgun S, et al. Pain prevention with intraoperative ketamine in outpatient children undergoing tonsillectomy or tonsillectomy and adenotomy. J Clin Anesth 2007;71:735–739 7. Murray WB, Yankelowitz SM, le Roux M, et al. Prevention of post-tonsillectomy pain with analgesic doses of ketamine. S Afr Med J 1987;72:839–842 8. McGrath PJ, Johnson G, Goodman JT, et al. CHEOPS: a behavioral scale for rating postoperative pain in children. In: Fields HL, Dubner R, Cervero F, eds. Advances in Pain Research and Therapy. Vol. 9. New York: Raven Press, 1985:395–402 9. Kakinohana M, Sugahara K. Level of consciousness affects the excitability of spinal motor neurones during propofol sedation in humans. Br J Anaesth 2006;742–746 10. Warwick JP, Mason DG. Obstructive sleep apnoea syndrome in children. Anaesthesia 1998;53:571–579 11. Rosen GM, Muckle RP, Mahowald MW, et al. Postoperative respiratory compromise in children with obstructive sleep apnea syndrome: can it be anticipated? Pediatrics 1994;93:784–788 12. Negus BH, Street NE. Midazolam-opioid combination and postoperative upper airway obstruction in children. Anaesth Intensive Care 1995;2:232–233 13. Atef A, Fawaz AA. Peritonsillar infiltration with tramadol improves pediatric tonsillectomy pain. Eur Arch Otorhinolaryngol 2008;265:571–574 14. Akbay BK, Yildizbas S, Guclu E, et al. Analgesic efficacy of topical tramadol in the control of postoperative pain in children after tonsillectomy. J Anesth 2010;24:705–708 15. Akkaya T, Bedirli N, Ceylan T, et al. Comparison of intravenous and peritonsillar infiltration of tramadol for postoperative pain relief in children following adenotonsillectomy. Eur J Anaesthesiol 2009;26: 333–337 16. Romsing J, Ostergaard D, Drozdziewicz D, et al. Diclofenac or acetaminophen for analgesia in paediatric tonsillectomy outpatients. Acta Anaesthesiol Scand 2000;44:291–295 17. Mather SJ, Peutrell JM. Postoperative morphine requirements, nausea and vomiting following anaesthesia for tonsillectomy. Comparison of intravenous morphine and non-opioid analgesic techniques. Paediatr Anaesth 1995;5:185–188 18. Schnabel A, Zahn PK, Pogatzki-Zahn EM. Use of ketamine in children—what are the next steps? Anaesth 2011;21:1080 19. Aspinall RL, Mayor A. A prospective randomized controlled study of the efficacy of ketamine for postoperative pain relief in children after tonsillectomy. Paediatr Anaesth 2001;11:333–336 20. Honarmand A, Safavi MR, Jamshidi M. The preventative analgesic effect of preincisional peritonsillar infiltration of two low doses ketamin
e24
for postoperative pain relief in children following adenotonsillectomy. A randomized, double-blind, placebo-controlled study. Paediatr Anaesth 2008;18:508–514
Modified Fixation of Acrylic Cranioplasty in the Setting of Titanium Allergy Jeremy C. Sinkin, MD,* Sara Loftin, MS,† Stephen B. Baker, MD, DDS* Abstract: Cranioplasty can be performed using a number of materials ranging from autologous tissue to metallic or acrylic alloplastic implants. In this report, we present a unique case of revision cranioplasty in a patient with titanium allergy using a prefabricated, custommade polymethylmethacrylate implant and a modified fixation technique without plates or screws. Key Words: Revision cranioplasty, polymethylmethacrylate, methylmethacrylate, fixation, titanium allergy
C
ranioplasty can be performed for calvarial defects resulting from numerous etiologies. The goal of cranioplasty in all cases is to preserve the rigid and protective integrity of the calvarium and restore aesthetic contour of the scalp while minimizing morbidity and potential complications. Many options for calvarial reconstruction exist, ranging from the use of autologous bone, to metallic or acrylic implants, to allograft. Although autologous bone graft remains the criterion standard for cranioplasty, alloplastic materials have been shown to be safe and effective.1,2 One potential complication arising from the use of alloplastic material in cranioplasty is hypersensitivity. Hypersensitivity to titanium or nickel precludes their use as implantable material, either as a cranioplasty mesh, or as plate and screw fixation of autologous bone or an alloplastic plate. In this report, we present a unique case of revision cranioplasty in an individual with titanium allergy, using a prefabricated, custommade polymethylmethacrylate (PMMA) implant secured only with fresh resin methylmethacrylate (MMA).
CLINICAL REPORT A 65-year-old Asian-American woman with a surgical history of right occipital craniotomy and cranioplasty for acoustic neuroma presented with suspected symptoms of delayed hypersensitivity reaction to the titanium mesh used to repair her calvarial defect years prior. The patient complained of chronic suboccipital headaches, swelling of her scalp, and a diffuse rash, which led her to seek treatment. The hypersensitivity to titanium was confirmed on patch testing From the *Department of Plastic Surgery, Medstar Georgetown University Hospital, and †School of Medicine, Georgetown University, Washington, DC. Received May 21, 2014. Accepted for publication July 31, 2014. Address correspondence and reprint requests to Stephen B. Baker, MD, DDS, Department of Plastic Surgery, Medstar Georgetown University Hospital, First Floor, PHC Bldg, 3800 Reservoir Rd, NW Washington, DC 20007; E-mail: [email protected] The authors report no conflicts of interest. Copyright © 2014 by Mutaz B. Habal, MD ISSN: 1049-2275 DOI: 10.1097/SCS.0000000000001253
© 2014 Mutaz B. Habal, MD
Copyright © 2014 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
The Journal of Craniofacial Surgery • Volume 26, Number 1, January 2015
by an outside provider. Hypersensitivity to other materials commonly used in bone cement was tested as well but were nonreactive. The patient failed to manage conservatively her symptoms, which were significantly affecting her quality of life. She elected to undergo a procedure by another surgeon whereby a PMMA overlay was placed on her titanium mesh with the intention of decreasing her allergic response. Unfortunately, the patient's symptoms persisted, which led her to request removal of the titanium mesh, necessitating revision cranioplasty without the use of metallic plates or screws.
Surgical Technique The patient was placed prone on the operating table after induction of general anesthesia. The operation was carried out with the assistance of a neurosurgeon. The patient's old scalp scar was sharply excised, and dissection was carried down to her old implant. Soft tissues were dissected and reflected off of the previously placed implant in the subpericranial plane. The patient's previous cranioplasty construct consisted of a titanium mesh secured with titanium screws and a PMMA overlay. The cement and underlying titanium mesh and screws were removed completely, and the integrity of exposed dura was confirmed. The custom-made implant (Fig. 1) was then brought into the field and ensured to fit appropriately in the calvarial defect. To secure the implant, radial grooves were burred into the outer cortex of the calvarium surrounding the defect to create mechanical undercuts (Fig. 2). The external surface of the implant was also scored using the power bur to roughen the PMMA surface and increase surface activation to the monomer. Liquid MMA monomer was then applied to the external surface of the implant before mixing powder polymer and liquid monomer on the back table in the usual fashion. The implant was again positioned into the defect, and the freshly prepared PMMA resin was applied to the surface of the implant and into the radial recesses. The construct was allowed to cure. After hardening, the implant was found to be securely in position with appropriate contour. The wound was irrigated and closed in anatomic layers.
DISCUSSION Many medical implants are composed of titanium. Titanium is often used in cranioplasty because it is believed to be bioinert and is rigid as well as compatible with magnetic resonance imaging.3 Although titanium allergy is rare, the possibility of substantial morbidity is real. Death after an acute hypersensitivity reaction to a titanium cranioplasty mesh has been reported.4 The challenge in our patient was to remove the offending implant and secure a custom acrylic mold without using plates and screws. The MMA is an organic compound composed of methacrylic acid ester with a polymerizable double bond. When the polymer powder is mixed with monomer liquid, the polymerization process initiates, and the material rapidly hardens, providing good mechanical stability in minutes.5 It is widely used in cranioplasty secondary to its ease of use and contouring, cost, strength, and radiolucency; however, major disadvantages include its highly exothermic polymerization process and poor tissue ingrowth. To reduce the potential
Brief Clinical Studies
FIGURE 2. A, Polymethylmethacrylate implant sitting in the model of the patient's calvarial defect. B, Yellow “dumbbells” indicate areas where mechanical undercuts were created in the skull and implant using a power bur.
damage to surrounding soft tissues, moistened neuropaddies are placed on the dura and the PMMA implant is continuously irrigated with saline as it hardens. The implant is then typically secured with screw anchors, which has demonstrated significantly increased bone adhesion force compared with an onlay construct.6 We have found another report of full-thickness calvarial reconstruction using PMMA without plates and screws. In his report, Yanai7 described molding a PMMA plate to fill the calvarial defect in a standard fashion. He then drilled holes through the exocortex angled into the defect. Holes are also drilled into the implant to allow tissue ingrowth. The plate is then replaced into the defect, and new viscous PMMA resin is applied through the calvarial holes filling the boneplate gap. Yanai7 reported performing this technique in more than 20 patients, without complication. Unlike Yanai, we chose to use a custom-made, prefabricated PMMA implant (Stryker, Kalamazoo, MI), rather than fashion one in the operating room. This decision was made solely to minimize in situ exothermic reaction and potential thermal damage to the dura mater. Computer-assisted design and computer-aided manufacturing of custom acrylic implants have been shown to be safe, accurate, and effective for the treatment of cranial defects.8 A standard craniofacial computed tomographic scan was obtained by the patient 2 weeks before the surgery. The images were sent to the manufacturing company. The company provided 2 custom, sterile, implantable PMMA plates and a sterile host bone model (defect) (Fig. 2). By using the prefabricated implant, we ensured a well-adapted fit and significantly reduced the risk for thermal damage to the dura. Polymethylmethacrylate is a commonly used material in dentistry and oral surgery for the fabrication of dentures and splints. In their biomechanical study, Vallittu et al9 demonstrated via scanning electron microscopy that application of liquid MMA monomer to a PMMA specimen dissolved the surface structure. In addition, the bonding of new acrylic resin to the surface of dissolved PMMA is accomplished via formation of new polymer chains. Borrowing from the experience of prosthetic dentistry, we were able to add new PMMA to the activated surface of our prefabricated implant with confidence. We have described a modified technique for acrylic cranioplasty fixation without the use of metal anchors. Although we chose to use a prefabricated implant, this technique is otherwise immediately available in most operating theaters that use MMA bone cement and standard cranioplasty instruments. The benefit of no titanium plates and screws for this unusual case came without any increase in blood loss, operative time, or cosmetic defect.
REFERENCES
FIGURE 1. The custom-made, prefabricated PMMA cranioplasty implant.
1. Reddy S, Khalifian S, Flores JM, et al. Clinical outcomes in cranioplasty: risk factors and choice of reconstructive material. Plast Reconstr Surg 2014;133:864–873 2. Al-Tamini YZ, Sinha P, Trivedi M, et al. Comparison of acrylic and titanium cranioplasty. Br J Neurosurg 2012;26:510–513 3. Mukherjee S, Thakur B, Haq I, et al. Complications of titanium cranioplasty—a retrospective analysis of 174 patients. Acta Neurochir (Wien) 2014;156:989–998
© 2014 Mutaz B. Habal, MD
Copyright © 2014 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
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The Journal of Craniofacial Surgery • Volume 26, Number 1, January 2015
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4. Hettige S, Norris JS. Mortality after local allergic response to titanium cranioplasty. Acta Neurochir (Wien) 2012;154:1725–1726 5. Lai PL, Chen LH, Chen WJ, et al. Chemical and physical properties of bone cement for vertebroplasty. Biomed J 2013;36:162–167 6. Nikolis A, Malhotra G, Tiftikcioglu Y, et al. Evaluation of polymethylmethacrylate adhesion: a comparison of direct onlay versus screw anchoring techniques. J Craniofac Surg 2009;20:366–371 7. Yanai A. Resin sealant: a new method of methyl methacrylate cranioplasty. Technical note. J Neurosurg 1991;75:328–330 8. Goh RC, Chang CN, Lin CL, et al. Customised fabricated implants after previous failed cranioplasty. J Plast Reconstr Aesthet Surg 2010;63:1479–1484 9. Vallittu PK, Lassila VP, Lappalainen R. Wetting the repair surface with methyl methacrylate affects the transverse strength of repaired heat-polymerized resin. J Prosthet Dent 1994;72:639–643
Endoscopic Removal of Giant Intranasal Schwannoma Rifat Karli, MD, Emre Ayhan, MD, Semsettin Kardas, MD, Esra Kavaz, MD, Meliksah Yilmaz, MD Abstract: Schwannoma is a benign neoplasm originating from schwann cells of the peripheral nerve sheath. Although nearly half of all schwannomas involve the head and neck region, nasal and paranasal sinus presentations are very rare in the literature. We present a case of nasal schwannoma originating from the right nasal cavity. A 59-year-old man presented with complaints of progressive right nasal obstruction and headache. Endoscopic examinations revealed a mass that filled the right middle meatus. At first glance, it was not like polyp tissue. Endoscopic sinus surgery was performed under general anesthesia, and the mass was completely removed. Key Words: Intranasal schwannoma, peripheral nerve sheath tumor
P
eripheral nerve sheath tumors can occur anywhere in the body. They are called schwannomas. Schwannomas of the nasal cavity and paranasal sinuses are quite rare. Twenty five percent to 45% of all schwannomas are located in the head and neck zone; however, nasal and paranasal schwannomas account for 4% of these tumors.1 A large part of these are benign, but some may be malignant. Malignant schwannomas are highly aggressive tumors.2 We report a case with intranasally benign schwannoma that is an uncommon presentation and discuss the clinicopathologic properties of this tumor.
CLINICAL REPORT A 59-year-old man presented with intermittent headaches and right nasal obstruction since the past year. Endoscopic examination revealed a polypoid lesion that filled the middle meatus. Computed tomographic (CT) scans revealed a large tumor obliterating the From the Department of Otorhinolaryngology, School of Medicine, Ondokuz Mayıs University Samsun, Samsun, Turkey. Received May 26, 2014. Accepted for publication July 31, 2014. Address correspondence and reprint requests to Rifat Karli, MD, KBB Kliniği, Ondokuz Mayis Universitesi Tip Fakültesi, Samsun, Turkey; E-mail: [email protected] The authors report no conflicts of interest. Copyright © 2014 by Mutaz B. Habal, MD ISSN: 1049-2275 DOI: 10.1097/SCS.0000000000001257
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FIGURE 1. Coronal, (A) and axial (B) computed tomographic scan. A, Giant tumor filling the right ethmoid and sphenoid sinus cavity. B, Carotid channel (black arrow) protrudes into the sphenoid sinus (bone wall intact).
right middle meatus, involving also the complete ethmoid region (Figs. 1A, B). There was no destruction of the lamina papyracea and intracranial extension on the right side. He underwent total excision of the tumor with endoscopic endonasal approach. The tumor was completely easily removed with dissection from surrounding structure (Fig. 2). Smooth surface occurred between the skull base, sphenoid sinus anterior border, and the lamina papiracea in the nasal cavity after resection of the tumor (Figs. 3A, B). The patient was discharged after the postoperative second day. Histopathologic examination revealed that the lesion was a schwannoma. The tumor has not shown recurrence on follow-up from one year.
DISCUSSION Unilateral nasal masses should be considered malignant until proven otherwise in adult patients. Macroscopic examination can give an idea about the type of mass. However, the definitive diagnosis is excisional biopsy. At first glance, we thought that our case may be inverted papillomas or malignant tumor with preoperative endoscopic examination, because it did not resemble the classic polyp tissue. Schwannomas were first described by Virchow in 1908. They are a benign slow-growing tumor that arises from Schwann cells. Cranial, peripheral, and autonomic nerves can produce myelin sheath, which arises from the Schwann cells.3 There is an exception in this regard, which is ophthalmic and olfactory nerves. Schwannoma cannot develop from these nerves because of the absence of Schwann cells in their sheaths.1 They may occur in the nasal cavity and paranasal sinuses. The most commonly involved sinus is the nasal ethmoid sinus followed by the maxillary sinus. The most important reason for this is that the ethmoid sinus is relatively more abundant and has more complex nerve innervations than other paranasal sinuses.4 The origin of schwannomas arising from paranasal sinuses is presumed to be from the peripheral nerve sheaths of the ophthalmic and maxillary divisions of the trigeminal nerves and their ganglion.5 Tumor expands by pushing the nerve sheath. The nerve fibers are stretched over its capsule. The treatment of choice of peripheral nerve sheath tumors is total surgical excision.3 The most appropriate method of operation is determined by the preoperative assessment. Preoperative research should include endoscopic examination, computed tomographic scanning, and/or magnetic resonance imaging. We were able to easily dissect schwannoma mass from the surrounding tissue and tumor clearance using an intranasal endoscopic approach. The
FIGURE 2. Removed tumor tissue.
© 2014 Mutaz B. Habal, MD
Copyright © 2014 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
Brief Clinical Studies
developed. It is seen as an advantage that ketamine can be administered in different routes at analgesic dosage and has a low incidence of adverse effects. Ketamine is considered as an alternative for administration to postoperative analgesic drugs such as the opioids, nonopioids, and nonsteroidal anti-inflammatory drugs.
REFERENCES 1. McNeill RA. A history of tonsillectomy: two millenia of trauma, haemorrhage and controversy. Ulster Med J 1960;29:59–63 2. Ugur MB, Yilmaz M, Altunkaya H, et al. Effect of intramuscular and peritonsillar injection of tramadol before tonsillectomy: a double blind randomized, placebo-controlled clinical trial. Int J Pediatr Otorhinolaryngol 2008;72:241–248 3. Engelhardt T, Steel E, Johnston G, et al. Tramadol for pain relief in children undergoing tonsillectomy; a comparison with morphine. Paediatr Anaesth 2003;13:249–252 4. Dal D, Celebi N, Elvan EG, et al. The efficacy of intravenous or peritonsillar infiltration of ketamine for postoperative in children following adenotonsillectomy. Paediatr Anaesth 2007;17:263–269 5. Umuroglu T, Eti Z, Ciftci H, et al. Analgesia for adenotonsillectomy in children: a comparison of morphine, ketamine, and tramadol. Paediatr Anaesth 2004;14:568–573 6. Aydin ON, Ugur B, Ozgun S, et al. Pain prevention with intraoperative ketamine in outpatient children undergoing tonsillectomy or tonsillectomy and adenotomy. J Clin Anesth 2007;71:735–739 7. Murray WB, Yankelowitz SM, le Roux M, et al. Prevention of post-tonsillectomy pain with analgesic doses of ketamine. S Afr Med J 1987;72:839–842 8. McGrath PJ, Johnson G, Goodman JT, et al. CHEOPS: a behavioral scale for rating postoperative pain in children. In: Fields HL, Dubner R, Cervero F, eds. Advances in Pain Research and Therapy. Vol. 9. New York: Raven Press, 1985:395–402 9. Kakinohana M, Sugahara K. Level of consciousness affects the excitability of spinal motor neurones during propofol sedation in humans. Br J Anaesth 2006;742–746 10. Warwick JP, Mason DG. Obstructive sleep apnoea syndrome in children. Anaesthesia 1998;53:571–579 11. Rosen GM, Muckle RP, Mahowald MW, et al. Postoperative respiratory compromise in children with obstructive sleep apnea syndrome: can it be anticipated? Pediatrics 1994;93:784–788 12. Negus BH, Street NE. Midazolam-opioid combination and postoperative upper airway obstruction in children. Anaesth Intensive Care 1995;2:232–233 13. Atef A, Fawaz AA. Peritonsillar infiltration with tramadol improves pediatric tonsillectomy pain. Eur Arch Otorhinolaryngol 2008;265:571–574 14. Akbay BK, Yildizbas S, Guclu E, et al. Analgesic efficacy of topical tramadol in the control of postoperative pain in children after tonsillectomy. J Anesth 2010;24:705–708 15. Akkaya T, Bedirli N, Ceylan T, et al. Comparison of intravenous and peritonsillar infiltration of tramadol for postoperative pain relief in children following adenotonsillectomy. Eur J Anaesthesiol 2009;26: 333–337 16. Romsing J, Ostergaard D, Drozdziewicz D, et al. Diclofenac or acetaminophen for analgesia in paediatric tonsillectomy outpatients. Acta Anaesthesiol Scand 2000;44:291–295 17. Mather SJ, Peutrell JM. Postoperative morphine requirements, nausea and vomiting following anaesthesia for tonsillectomy. Comparison of intravenous morphine and non-opioid analgesic techniques. Paediatr Anaesth 1995;5:185–188 18. Schnabel A, Zahn PK, Pogatzki-Zahn EM. Use of ketamine in children—what are the next steps? Anaesth 2011;21:1080 19. Aspinall RL, Mayor A. A prospective randomized controlled study of the efficacy of ketamine for postoperative pain relief in children after tonsillectomy. Paediatr Anaesth 2001;11:333–336 20. Honarmand A, Safavi MR, Jamshidi M. The preventative analgesic effect of preincisional peritonsillar infiltration of two low doses ketamin
e24
for postoperative pain relief in children following adenotonsillectomy. A randomized, double-blind, placebo-controlled study. Paediatr Anaesth 2008;18:508–514
Modified Fixation of Acrylic Cranioplasty in the Setting of Titanium Allergy Jeremy C. Sinkin, MD,* Sara Loftin, MS,† Stephen B. Baker, MD, DDS* Abstract: Cranioplasty can be performed using a number of materials ranging from autologous tissue to metallic or acrylic alloplastic implants. In this report, we present a unique case of revision cranioplasty in a patient with titanium allergy using a prefabricated, custommade polymethylmethacrylate implant and a modified fixation technique without plates or screws. Key Words: Revision cranioplasty, polymethylmethacrylate, methylmethacrylate, fixation, titanium allergy
C
ranioplasty can be performed for calvarial defects resulting from numerous etiologies. The goal of cranioplasty in all cases is to preserve the rigid and protective integrity of the calvarium and restore aesthetic contour of the scalp while minimizing morbidity and potential complications. Many options for calvarial reconstruction exist, ranging from the use of autologous bone, to metallic or acrylic implants, to allograft. Although autologous bone graft remains the criterion standard for cranioplasty, alloplastic materials have been shown to be safe and effective.1,2 One potential complication arising from the use of alloplastic material in cranioplasty is hypersensitivity. Hypersensitivity to titanium or nickel precludes their use as implantable material, either as a cranioplasty mesh, or as plate and screw fixation of autologous bone or an alloplastic plate. In this report, we present a unique case of revision cranioplasty in an individual with titanium allergy, using a prefabricated, custommade polymethylmethacrylate (PMMA) implant secured only with fresh resin methylmethacrylate (MMA).
CLINICAL REPORT A 65-year-old Asian-American woman with a surgical history of right occipital craniotomy and cranioplasty for acoustic neuroma presented with suspected symptoms of delayed hypersensitivity reaction to the titanium mesh used to repair her calvarial defect years prior. The patient complained of chronic suboccipital headaches, swelling of her scalp, and a diffuse rash, which led her to seek treatment. The hypersensitivity to titanium was confirmed on patch testing From the *Department of Plastic Surgery, Medstar Georgetown University Hospital, and †School of Medicine, Georgetown University, Washington, DC. Received May 21, 2014. Accepted for publication July 31, 2014. Address correspondence and reprint requests to Stephen B. Baker, MD, DDS, Department of Plastic Surgery, Medstar Georgetown University Hospital, First Floor, PHC Bldg, 3800 Reservoir Rd, NW Washington, DC 20007; E-mail: [email protected] The authors report no conflicts of interest. Copyright © 2014 by Mutaz B. Habal, MD ISSN: 1049-2275 DOI: 10.1097/SCS.0000000000001253
© 2014 Mutaz B. Habal, MD
Copyright © 2014 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
The Journal of Craniofacial Surgery • Volume 26, Number 1, January 2015
by an outside provider. Hypersensitivity to other materials commonly used in bone cement was tested as well but were nonreactive. The patient failed to manage conservatively her symptoms, which were significantly affecting her quality of life. She elected to undergo a procedure by another surgeon whereby a PMMA overlay was placed on her titanium mesh with the intention of decreasing her allergic response. Unfortunately, the patient's symptoms persisted, which led her to request removal of the titanium mesh, necessitating revision cranioplasty without the use of metallic plates or screws.
Surgical Technique The patient was placed prone on the operating table after induction of general anesthesia. The operation was carried out with the assistance of a neurosurgeon. The patient's old scalp scar was sharply excised, and dissection was carried down to her old implant. Soft tissues were dissected and reflected off of the previously placed implant in the subpericranial plane. The patient's previous cranioplasty construct consisted of a titanium mesh secured with titanium screws and a PMMA overlay. The cement and underlying titanium mesh and screws were removed completely, and the integrity of exposed dura was confirmed. The custom-made implant (Fig. 1) was then brought into the field and ensured to fit appropriately in the calvarial defect. To secure the implant, radial grooves were burred into the outer cortex of the calvarium surrounding the defect to create mechanical undercuts (Fig. 2). The external surface of the implant was also scored using the power bur to roughen the PMMA surface and increase surface activation to the monomer. Liquid MMA monomer was then applied to the external surface of the implant before mixing powder polymer and liquid monomer on the back table in the usual fashion. The implant was again positioned into the defect, and the freshly prepared PMMA resin was applied to the surface of the implant and into the radial recesses. The construct was allowed to cure. After hardening, the implant was found to be securely in position with appropriate contour. The wound was irrigated and closed in anatomic layers.
DISCUSSION Many medical implants are composed of titanium. Titanium is often used in cranioplasty because it is believed to be bioinert and is rigid as well as compatible with magnetic resonance imaging.3 Although titanium allergy is rare, the possibility of substantial morbidity is real. Death after an acute hypersensitivity reaction to a titanium cranioplasty mesh has been reported.4 The challenge in our patient was to remove the offending implant and secure a custom acrylic mold without using plates and screws. The MMA is an organic compound composed of methacrylic acid ester with a polymerizable double bond. When the polymer powder is mixed with monomer liquid, the polymerization process initiates, and the material rapidly hardens, providing good mechanical stability in minutes.5 It is widely used in cranioplasty secondary to its ease of use and contouring, cost, strength, and radiolucency; however, major disadvantages include its highly exothermic polymerization process and poor tissue ingrowth. To reduce the potential
Brief Clinical Studies
FIGURE 2. A, Polymethylmethacrylate implant sitting in the model of the patient's calvarial defect. B, Yellow “dumbbells” indicate areas where mechanical undercuts were created in the skull and implant using a power bur.
damage to surrounding soft tissues, moistened neuropaddies are placed on the dura and the PMMA implant is continuously irrigated with saline as it hardens. The implant is then typically secured with screw anchors, which has demonstrated significantly increased bone adhesion force compared with an onlay construct.6 We have found another report of full-thickness calvarial reconstruction using PMMA without plates and screws. In his report, Yanai7 described molding a PMMA plate to fill the calvarial defect in a standard fashion. He then drilled holes through the exocortex angled into the defect. Holes are also drilled into the implant to allow tissue ingrowth. The plate is then replaced into the defect, and new viscous PMMA resin is applied through the calvarial holes filling the boneplate gap. Yanai7 reported performing this technique in more than 20 patients, without complication. Unlike Yanai, we chose to use a custom-made, prefabricated PMMA implant (Stryker, Kalamazoo, MI), rather than fashion one in the operating room. This decision was made solely to minimize in situ exothermic reaction and potential thermal damage to the dura mater. Computer-assisted design and computer-aided manufacturing of custom acrylic implants have been shown to be safe, accurate, and effective for the treatment of cranial defects.8 A standard craniofacial computed tomographic scan was obtained by the patient 2 weeks before the surgery. The images were sent to the manufacturing company. The company provided 2 custom, sterile, implantable PMMA plates and a sterile host bone model (defect) (Fig. 2). By using the prefabricated implant, we ensured a well-adapted fit and significantly reduced the risk for thermal damage to the dura. Polymethylmethacrylate is a commonly used material in dentistry and oral surgery for the fabrication of dentures and splints. In their biomechanical study, Vallittu et al9 demonstrated via scanning electron microscopy that application of liquid MMA monomer to a PMMA specimen dissolved the surface structure. In addition, the bonding of new acrylic resin to the surface of dissolved PMMA is accomplished via formation of new polymer chains. Borrowing from the experience of prosthetic dentistry, we were able to add new PMMA to the activated surface of our prefabricated implant with confidence. We have described a modified technique for acrylic cranioplasty fixation without the use of metal anchors. Although we chose to use a prefabricated implant, this technique is otherwise immediately available in most operating theaters that use MMA bone cement and standard cranioplasty instruments. The benefit of no titanium plates and screws for this unusual case came without any increase in blood loss, operative time, or cosmetic defect.
REFERENCES
FIGURE 1. The custom-made, prefabricated PMMA cranioplasty implant.
1. Reddy S, Khalifian S, Flores JM, et al. Clinical outcomes in cranioplasty: risk factors and choice of reconstructive material. Plast Reconstr Surg 2014;133:864–873 2. Al-Tamini YZ, Sinha P, Trivedi M, et al. Comparison of acrylic and titanium cranioplasty. Br J Neurosurg 2012;26:510–513 3. Mukherjee S, Thakur B, Haq I, et al. Complications of titanium cranioplasty—a retrospective analysis of 174 patients. Acta Neurochir (Wien) 2014;156:989–998
© 2014 Mutaz B. Habal, MD
Copyright © 2014 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
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The Journal of Craniofacial Surgery • Volume 26, Number 1, January 2015
Brief Clinical Studies
4. Hettige S, Norris JS. Mortality after local allergic response to titanium cranioplasty. Acta Neurochir (Wien) 2012;154:1725–1726 5. Lai PL, Chen LH, Chen WJ, et al. Chemical and physical properties of bone cement for vertebroplasty. Biomed J 2013;36:162–167 6. Nikolis A, Malhotra G, Tiftikcioglu Y, et al. Evaluation of polymethylmethacrylate adhesion: a comparison of direct onlay versus screw anchoring techniques. J Craniofac Surg 2009;20:366–371 7. Yanai A. Resin sealant: a new method of methyl methacrylate cranioplasty. Technical note. J Neurosurg 1991;75:328–330 8. Goh RC, Chang CN, Lin CL, et al. Customised fabricated implants after previous failed cranioplasty. J Plast Reconstr Aesthet Surg 2010;63:1479–1484 9. Vallittu PK, Lassila VP, Lappalainen R. Wetting the repair surface with methyl methacrylate affects the transverse strength of repaired heat-polymerized resin. J Prosthet Dent 1994;72:639–643
Endoscopic Removal of Giant Intranasal Schwannoma Rifat Karli, MD, Emre Ayhan, MD, Semsettin Kardas, MD, Esra Kavaz, MD, Meliksah Yilmaz, MD Abstract: Schwannoma is a benign neoplasm originating from schwann cells of the peripheral nerve sheath. Although nearly half of all schwannomas involve the head and neck region, nasal and paranasal sinus presentations are very rare in the literature. We present a case of nasal schwannoma originating from the right nasal cavity. A 59-year-old man presented with complaints of progressive right nasal obstruction and headache. Endoscopic examinations revealed a mass that filled the right middle meatus. At first glance, it was not like polyp tissue. Endoscopic sinus surgery was performed under general anesthesia, and the mass was completely removed. Key Words: Intranasal schwannoma, peripheral nerve sheath tumor
P
eripheral nerve sheath tumors can occur anywhere in the body. They are called schwannomas. Schwannomas of the nasal cavity and paranasal sinuses are quite rare. Twenty five percent to 45% of all schwannomas are located in the head and neck zone; however, nasal and paranasal schwannomas account for 4% of these tumors.1 A large part of these are benign, but some may be malignant. Malignant schwannomas are highly aggressive tumors.2 We report a case with intranasally benign schwannoma that is an uncommon presentation and discuss the clinicopathologic properties of this tumor.
CLINICAL REPORT A 59-year-old man presented with intermittent headaches and right nasal obstruction since the past year. Endoscopic examination revealed a polypoid lesion that filled the middle meatus. Computed tomographic (CT) scans revealed a large tumor obliterating the From the Department of Otorhinolaryngology, School of Medicine, Ondokuz Mayıs University Samsun, Samsun, Turkey. Received May 26, 2014. Accepted for publication July 31, 2014. Address correspondence and reprint requests to Rifat Karli, MD, KBB Kliniği, Ondokuz Mayis Universitesi Tip Fakültesi, Samsun, Turkey; E-mail: [email protected] The authors report no conflicts of interest. Copyright © 2014 by Mutaz B. Habal, MD ISSN: 1049-2275 DOI: 10.1097/SCS.0000000000001257
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FIGURE 1. Coronal, (A) and axial (B) computed tomographic scan. A, Giant tumor filling the right ethmoid and sphenoid sinus cavity. B, Carotid channel (black arrow) protrudes into the sphenoid sinus (bone wall intact).
right middle meatus, involving also the complete ethmoid region (Figs. 1A, B). There was no destruction of the lamina papyracea and intracranial extension on the right side. He underwent total excision of the tumor with endoscopic endonasal approach. The tumor was completely easily removed with dissection from surrounding structure (Fig. 2). Smooth surface occurred between the skull base, sphenoid sinus anterior border, and the lamina papiracea in the nasal cavity after resection of the tumor (Figs. 3A, B). The patient was discharged after the postoperative second day. Histopathologic examination revealed that the lesion was a schwannoma. The tumor has not shown recurrence on follow-up from one year.
DISCUSSION Unilateral nasal masses should be considered malignant until proven otherwise in adult patients. Macroscopic examination can give an idea about the type of mass. However, the definitive diagnosis is excisional biopsy. At first glance, we thought that our case may be inverted papillomas or malignant tumor with preoperative endoscopic examination, because it did not resemble the classic polyp tissue. Schwannomas were first described by Virchow in 1908. They are a benign slow-growing tumor that arises from Schwann cells. Cranial, peripheral, and autonomic nerves can produce myelin sheath, which arises from the Schwann cells.3 There is an exception in this regard, which is ophthalmic and olfactory nerves. Schwannoma cannot develop from these nerves because of the absence of Schwann cells in their sheaths.1 They may occur in the nasal cavity and paranasal sinuses. The most commonly involved sinus is the nasal ethmoid sinus followed by the maxillary sinus. The most important reason for this is that the ethmoid sinus is relatively more abundant and has more complex nerve innervations than other paranasal sinuses.4 The origin of schwannomas arising from paranasal sinuses is presumed to be from the peripheral nerve sheaths of the ophthalmic and maxillary divisions of the trigeminal nerves and their ganglion.5 Tumor expands by pushing the nerve sheath. The nerve fibers are stretched over its capsule. The treatment of choice of peripheral nerve sheath tumors is total surgical excision.3 The most appropriate method of operation is determined by the preoperative assessment. Preoperative research should include endoscopic examination, computed tomographic scanning, and/or magnetic resonance imaging. We were able to easily dissect schwannoma mass from the surrounding tissue and tumor clearance using an intranasal endoscopic approach. The
FIGURE 2. Removed tumor tissue.
© 2014 Mutaz B. Habal, MD
Copyright © 2014 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
