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Subdural hematoma – a rare complication of removal of osseointegrated auricular prosthesis retention system
G Model PEDOT 7135 No. of Pages 3
International Journal of Pediatric Otorhinolaryngology xxx (2014) xxx–xxx
Contents lists available at ScienceDirect
International Journal of Pediatric Otorhinolaryngology journal homepage: www.elsevier.com/locate/ijporl
Case report
Subdural hematoma – a rare complication of removal of osseointegrated auricular prosthesis retention system Brent G. Nichols a , Sean M. Lew b , Joseph E. Kerschner c, * a
Department of Otolaryngology and Communication Sciences, Medical College of Wisconsin, 2557 N 68th Street, Wauwatosa, WI 53213, USA Department of Neurosurgery, Medical College of Wisconsin, 9200 W. Wisconsin Avenue, Milwaukee, WI 53266, USA c Department of Otolaryngology and Communication Sciences, Medical College of Wisconsin, 9200 W. Wisconsin Avenue, Milwaukee, WI 53266, USA b
A R T I C L E I N F O
A B S T R A C T
Article history: Received 11 March 2014 Received in revised form 10 May 2014 Accepted 13 May 2014 Available online xxx
Periauricular osseointegrated prosthesis retention systems have been proven safe and effective in the management of microtia. Intracranial hemorrhage has been previously reported with implantation but is rare. We report a case of subdural hemorrhage following removal of an auricular prosthesis implant system. This case highlights the role of imaging, surgical technique, and neurosurgical support in prevention and management of intracranial hemorrhage associated with osseointegrated device removal. ã 2014 Elsevier Ireland Ltd. All rights reserved.
Keywords: Vestifix BAHA BAHA complication Vestifix complication Osseointegrated implant Subdural hematoma
1. Introduction Microtia has physiological, psychological and social significance and management options include both surgical reconstruction of the ear as well as auricular prostheses. Modern prostheses are of high quality and provide excellent cosmetic and functional outcomes [1]. Periauricular osseointegrated prosthesis retention systems have a proven safety record with a low rate of complications, the most common of which is skin irritation. Serious intra-cranial complications are rare [2,3]. In this case report, we describe a patient that developed a subdural hemorrhage following removal of an auricular prosthesis implant system. 2. Case Report The patient is a 3 year old male who presented to our pediatric otolaryngology clinic for evaluation and management of bilateral congenital microtia with canal atresia. He underwent simultaneous bilateral implantation of a Baha1 and Vistafix1 System (CochlearTM Corporation, CO, USA) for auricular prosthesis and sound processor retention. A second stage procedure was
* Corresponding author. Tel.: +1 414 266 6486; fax.: +1 414 266 2693. E-mail addresses: [email protected] (B.G. Nichols), [email protected] (S.M. Lew) , [email protected] (J.E. Kerschner).
performed six months later with the removal of healing screws and placement of abutments. Following the second stage implantation, the patient developed chronic irritation surrounding the left ear prosthesis implant site, which was refractory to local wound cares and antibiotics. The external abutments were removed five months later and healing caps were placed. Despite these efforts, he continued to have irritation over one of the Vistafix sites, and there was concern for a chronic implant-associated infection. One year following initial implantation, the patient was taken to the operating room for removal of the left ear implant. The implant was exposed, and a 1-mm diamond burr was used to partially free the implant. During the removal of the implant, a moderate amount of venous bleeding was noted and hemostasis was obtained with application of bone wax. After the osseointegrated implant was completely removed, there was a 4–5 mm defect in the inner cortical table with exposed dura, which was inspected and appeared to be intact. The wound was then closed, and the patient was transferred to the postoperative recovery unit following extubation. Given that there was greater than expected venous bleeding, neurosurgery was consulted inter-operatively. We then planned for ICU observation and a CT of the head in four hours. Several minutes after arriving in the recovery unit, the patient developed fixed and dilated pupils. Rapid reintubation, hyperventilation, mannitol, furosemide, and head elevation were
http://dx.doi.org/10.1016/j.ijporl.2014.05.016 0165-5876/ ã 2014 Elsevier Ireland Ltd. All rights reserved.
Please cite this article in press as: B.G. Nichols, et al., Subdural hematoma – a rare complication of removal of osseointegrated auricular prosthesis retention system, Int. J. Pediatr. Otorhinolaryngol. (2014), http://dx.doi.org/10.1016/j.ijporl.2014.05.016
G Model PEDOT 7135 No. of Pages 3
2
B.G. Nichols et al. / International Journal of Pediatric Otorhinolaryngology xxx (2014) xxx–xxx
immediately initiated as temporizing measures. The patient was urgently transferred to the operating room and surgical exploration was initiated to treat the presumed intracranial hemorrhage in conjunction with the neurosurgical service. The incision was reopened and the bone wax was removed from the cranial defect. This revealed a small dural defect, approximately 1 mm in diameter without active bleeding. The cranial defect was used as an epidural access point for the creation of a small craniotomy (2 cm diameter). The dura was notably relaxed. The epidural space was explored and epidural hematoma was ruled out. Ultrasound was performed which failed to reveal an intraparenchymal hemorrhage. The decision was made to not open the dura. Due to the proximity of the initial procedure to the transverse sinus, the decision was made to perform an exploratory burr hole over the posterior fossa to rule out a posterior fossa epidural hematoma. This was performed without event; no epidural hematoma was encountered. The incisions were closed and the pupils were noted to be smaller and reactive. The patient was kept intubated, and an urgent brain MRI was performed (Fig. 1), which identified an acute left subdural hematoma with mass effect and midline shift. The patient was immediately returned to the operating room. A standard left frontotemporoparietal craniotomy was performed. Upon dural opening, acute subdural hematoma was actively expressed and evacuated. While evacuating the hematoma a laceration in the vein of Labbe was identified at the site of the initial device explantation and dural defect. This site re-bled upon removal of the hematoma and hemostasis was achieved with Avitene1, Gelfoam1 and Tisseel1. An intraparenchymal intracranial pressure (ICP) monitor was placed following completion of the craniotomy. Post-operatively, the patient’s ICP was normal and pupils were noted to be reactive and appropriate. He was extubated on postoperative day #1 (POD #1) at which time he was non-verbal with a dense right hemiplegia. MRI on POD #2 demonstrated resolved midline shift, with multiple small areas of restricted diffusion and T2/FLAIR hyperintensity consistent with infarction involving the left basal ganglia, hippocampus, thalamus, internal capsule, precentral gyrus and the right thalamus. He was managed with aggressive inpatient physical, occupational and speech therapy and was transitioned to outpatient care at 3 weeks. At three months follow up he was able to ambulate independently, tolerated a normal diet, and his expressive aphasia was improving.
Fig. 1. T2 MRI axial sequence with a left frontoparietal convexity (arrow) consistent with subdural hematoma causing mass effect and rightward shift of midline structures.
3. Discussion Osseointegrated bone conduction hearing systems (e.g., Baha) have been used clinically for more than 30 years, and worldwide on more than 100,000 patients. Osseointegrated systems have been used to secure auricular prostheses for decades with FDA approval since 1985 [3,4]. They have been shown to have an excellent safety profile and lead to improvements in quality of life [1]. They have a low rate of complications (4–6%), with skin breakdown and skin irritation being the most common [1,5,6]. Despite the overall favorable safety profile, there have been rare case reports of intra-cranial complications associated with temporal bone osseointegrated systems. Reported intra-cranial complications include sigmoid sinus thrombosis, temporal lobe abscess, and epidural hematoma [2,7,8]. We are unaware of previous reports of subdural hemorrhage from removal of osseointegrated systems. We have commonly placed osseointegrated devices; however, it is rare for us to remove these implants. Due to protracted site irritation, failure of antibiotics and local wound cares, and parental desire to remove the infected implant, removal was indicated. This case highlights a serious complication of placement/removal of auricular prosthesis osseointegrated implant. Awareness and understanding of this potential complication may provide assistance to those individuals that perform these procedures. Patients with irritation or infection around implant sites should be managed with the least invasive modality possible. In this case, our patient was treated with wound cares and antibiotics prior to any operative intervention. The first operative treatment was to remove the abutment and place healing caps, it was not until these interventions failed that we considered removal of the implant. There are several possible explanations for the development of the subdural hematoma in this patient. First, when the implant was initially inserted, it may have penetrated the dura and/or injured the vein. Alternatively, the implant may have eroded through the dura and/or vein over time with brain and skull growth. Removal of such an implant could then have caused acute injury to the vein. Finally, surgical instruments used to remove the implant may have resulted in traumatic entry into previously intact dura and/or vein. Skull thickness during development is variable and as such mastoid osseointegrated systems are FDA approved for children 5 years of age and older [9,10], but frequently are implanted at an earlier age due to the significant benefit that children receive from these implants when compared to non-surgical hearing aids [11] We obtain CT scans of the temporal bone as standard practice to assess temporal bone for adequate thickness prior to implantation [5]. There were no findings on the CT in this case to suggest placement would be challenging, additionally, there were no complications or excessive bleeding with either the first or second stage procedure to suggest injury of the dura or underlying vasculature. Although not obtained in this patient, consideration of an additional CT scan prior to device removal may be warranted. An additional CT scan can demonstrate intracranial extension of a device. This is illustrated by the post-operative head CT in this case which demonstrates the right implant traversing the squamous portion of the temporal bone (Fig. 2). However, in young children, presumption of device proximity to underlying dura would be recommended. This case also emphasizes the need for intra-operative vigilance during removal of osseo-integrated implants and acknowledgement of the potential of serious intracranial complications with this procedure. Based on this case, and discussion following, our surgical approach for any future device removal would include performing a larger (1–2 cm) craniotomy initially when removing the implant to provide better exposure and allow earlier identification of intracranial structures and injury. Additionally, this procedure should be performed in a setting with neurosurgical support readily available.
Please cite this article in press as: B.G. Nichols, et al., Subdural hematoma – a rare complication of removal of osseointegrated auricular prosthesis retention system, Int. J. Pediatr. Otorhinolaryngol. (2014), http://dx.doi.org/10.1016/j.ijporl.2014.05.016
G Model PEDOT 7135 No. of Pages 3
B.G. Nichols et al. / International Journal of Pediatric Otorhinolaryngology xxx (2014) xxx–xxx
3
during implantation or removal and require rapid recognition and response to mitigate poor outcomes. References
Fig. 2. CT scan without contrast of the head demonstrating the intracranial position of right ear implant (arrow).
In this case, vigilant post-operative care with early recognition in the recovery room allowed prompt treatment, which was imperative to maximize the patient’s outcome. 4. Conclusion Implants in the mastoid area are an important aid for retention of auricular prostheses, but may have life-threatening intracranial consequences. Serious intra-cranial complications can occur
[1] H. Kievit, G.W. Verhage-Damen, K.J. Ingels, E.A. Mylanus, M.K. Hol, Long-term quality of life assessment in patients with auricular prostheses, J. Craniofac. Surg. 24 (2) (2013) 392–397. [2] B.W. Rotenberg, A.L. James, D. Fisher, et al., Establishment of a bone-anchored auricular prosthesis (BAAP) program, Int. J. Pediatr. Otorhinolaryngol. 66 (2002) 273–279. [3] A. Gaggl, H. Rainer, H. Scharfegger, D. Attelscheck, F.M. Chiari, Sigmoid and transverse sinus thrombosis caused by mastoid implant — case report, J. Craniomaxillofac. Surg. 32 (5) (2004) 324–329. [4] C.A. Dun, M.J. de Wolf, M.K. Hol, et al., Stability, survival, and tolerability of a novel Baha implant system: six-month data from a multicenter clinical investigation, Otol. Neurotol. 32 (6) (2011) 1001–1007. [5] G. Ricci, A. Della Volpe, M. Faralli, et al., Results and complications of the Baha system (bone-anchored hearing aid), Eur. Arch. Otorhinolaryngol. 267 (10) (2010) 1539–1545. [6] K.K. Hamming, T.W. Lund, T.A. Lander, J.D. Sidman, Complications and satisfaction with pediatric osseointegrated external ear prostheses, Laryngoscope 119 (2009) 1270–1273. [7] M. Scholz, H. Eufinger, A. Anders, et al., Intracerebral abscess after abutment change of a bone anchored hearing aid (BAHA), Otol. Neurotol. 24 (6) (2003) 896–899. [8] F.B. Mesfin, N.W. Perkins, C. Brook, D. Foyt, J.W. German, Epidural hematoma after typanomastoidectomy and bone-anchored hearing aid placement: case report, Neurosurgery 67 (2010) E1451–E1453. [9] P.A. Federspil, S.H. Tretbar, F.H. Böhlen, S. Rohde, S. Glaser, P.K. Plinkert, Measurement of skull bone thickness for bone-anchored hearing aids: an experimental study comparing both a novel ultrasound system (SonoPointer) and computed tomographic scanning to mechanical measurements, Otol. Neurotol. 31 (3) (2010) 440–446. [10] S. Roman, R. Nicollas, J.M. Triglia, Practice guidelines for bone-anchored hearing aids in children, Eur. Ann. Otorhinolaryngol. Head Neck Dis. 128 (5) (2011) 253–258. [11] N. Verstraeten, A.J. Zarowski, T. Somers, D. Riff, E.F. Offeciers, Comparison of the audiologic results obtained with the bone-anchored hearing aid attached to the headband, the testband and the “snap” abutment, Otol. Neurotol. 30 (2008) 70–75.
Please cite this article in press as: B.G. Nichols, et al., Subdural hematoma – a rare complication of removal of osseointegrated auricular prosthesis retention system, Int. J. Pediatr. Otorhinolaryngol. (2014), http://dx.doi.org/10.1016/j.ijporl.2014.05.016
International Journal of Pediatric Otorhinolaryngology xxx (2014) xxx–xxx
Contents lists available at ScienceDirect
International Journal of Pediatric Otorhinolaryngology journal homepage: www.elsevier.com/locate/ijporl
Case report
Subdural hematoma – a rare complication of removal of osseointegrated auricular prosthesis retention system Brent G. Nichols a , Sean M. Lew b , Joseph E. Kerschner c, * a
Department of Otolaryngology and Communication Sciences, Medical College of Wisconsin, 2557 N 68th Street, Wauwatosa, WI 53213, USA Department of Neurosurgery, Medical College of Wisconsin, 9200 W. Wisconsin Avenue, Milwaukee, WI 53266, USA c Department of Otolaryngology and Communication Sciences, Medical College of Wisconsin, 9200 W. Wisconsin Avenue, Milwaukee, WI 53266, USA b
A R T I C L E I N F O
A B S T R A C T
Article history: Received 11 March 2014 Received in revised form 10 May 2014 Accepted 13 May 2014 Available online xxx
Periauricular osseointegrated prosthesis retention systems have been proven safe and effective in the management of microtia. Intracranial hemorrhage has been previously reported with implantation but is rare. We report a case of subdural hemorrhage following removal of an auricular prosthesis implant system. This case highlights the role of imaging, surgical technique, and neurosurgical support in prevention and management of intracranial hemorrhage associated with osseointegrated device removal. ã 2014 Elsevier Ireland Ltd. All rights reserved.
Keywords: Vestifix BAHA BAHA complication Vestifix complication Osseointegrated implant Subdural hematoma
1. Introduction Microtia has physiological, psychological and social significance and management options include both surgical reconstruction of the ear as well as auricular prostheses. Modern prostheses are of high quality and provide excellent cosmetic and functional outcomes [1]. Periauricular osseointegrated prosthesis retention systems have a proven safety record with a low rate of complications, the most common of which is skin irritation. Serious intra-cranial complications are rare [2,3]. In this case report, we describe a patient that developed a subdural hemorrhage following removal of an auricular prosthesis implant system. 2. Case Report The patient is a 3 year old male who presented to our pediatric otolaryngology clinic for evaluation and management of bilateral congenital microtia with canal atresia. He underwent simultaneous bilateral implantation of a Baha1 and Vistafix1 System (CochlearTM Corporation, CO, USA) for auricular prosthesis and sound processor retention. A second stage procedure was
* Corresponding author. Tel.: +1 414 266 6486; fax.: +1 414 266 2693. E-mail addresses: [email protected] (B.G. Nichols), [email protected] (S.M. Lew) , [email protected] (J.E. Kerschner).
performed six months later with the removal of healing screws and placement of abutments. Following the second stage implantation, the patient developed chronic irritation surrounding the left ear prosthesis implant site, which was refractory to local wound cares and antibiotics. The external abutments were removed five months later and healing caps were placed. Despite these efforts, he continued to have irritation over one of the Vistafix sites, and there was concern for a chronic implant-associated infection. One year following initial implantation, the patient was taken to the operating room for removal of the left ear implant. The implant was exposed, and a 1-mm diamond burr was used to partially free the implant. During the removal of the implant, a moderate amount of venous bleeding was noted and hemostasis was obtained with application of bone wax. After the osseointegrated implant was completely removed, there was a 4–5 mm defect in the inner cortical table with exposed dura, which was inspected and appeared to be intact. The wound was then closed, and the patient was transferred to the postoperative recovery unit following extubation. Given that there was greater than expected venous bleeding, neurosurgery was consulted inter-operatively. We then planned for ICU observation and a CT of the head in four hours. Several minutes after arriving in the recovery unit, the patient developed fixed and dilated pupils. Rapid reintubation, hyperventilation, mannitol, furosemide, and head elevation were
http://dx.doi.org/10.1016/j.ijporl.2014.05.016 0165-5876/ ã 2014 Elsevier Ireland Ltd. All rights reserved.
Please cite this article in press as: B.G. Nichols, et al., Subdural hematoma – a rare complication of removal of osseointegrated auricular prosthesis retention system, Int. J. Pediatr. Otorhinolaryngol. (2014), http://dx.doi.org/10.1016/j.ijporl.2014.05.016
G Model PEDOT 7135 No. of Pages 3
2
B.G. Nichols et al. / International Journal of Pediatric Otorhinolaryngology xxx (2014) xxx–xxx
immediately initiated as temporizing measures. The patient was urgently transferred to the operating room and surgical exploration was initiated to treat the presumed intracranial hemorrhage in conjunction with the neurosurgical service. The incision was reopened and the bone wax was removed from the cranial defect. This revealed a small dural defect, approximately 1 mm in diameter without active bleeding. The cranial defect was used as an epidural access point for the creation of a small craniotomy (2 cm diameter). The dura was notably relaxed. The epidural space was explored and epidural hematoma was ruled out. Ultrasound was performed which failed to reveal an intraparenchymal hemorrhage. The decision was made to not open the dura. Due to the proximity of the initial procedure to the transverse sinus, the decision was made to perform an exploratory burr hole over the posterior fossa to rule out a posterior fossa epidural hematoma. This was performed without event; no epidural hematoma was encountered. The incisions were closed and the pupils were noted to be smaller and reactive. The patient was kept intubated, and an urgent brain MRI was performed (Fig. 1), which identified an acute left subdural hematoma with mass effect and midline shift. The patient was immediately returned to the operating room. A standard left frontotemporoparietal craniotomy was performed. Upon dural opening, acute subdural hematoma was actively expressed and evacuated. While evacuating the hematoma a laceration in the vein of Labbe was identified at the site of the initial device explantation and dural defect. This site re-bled upon removal of the hematoma and hemostasis was achieved with Avitene1, Gelfoam1 and Tisseel1. An intraparenchymal intracranial pressure (ICP) monitor was placed following completion of the craniotomy. Post-operatively, the patient’s ICP was normal and pupils were noted to be reactive and appropriate. He was extubated on postoperative day #1 (POD #1) at which time he was non-verbal with a dense right hemiplegia. MRI on POD #2 demonstrated resolved midline shift, with multiple small areas of restricted diffusion and T2/FLAIR hyperintensity consistent with infarction involving the left basal ganglia, hippocampus, thalamus, internal capsule, precentral gyrus and the right thalamus. He was managed with aggressive inpatient physical, occupational and speech therapy and was transitioned to outpatient care at 3 weeks. At three months follow up he was able to ambulate independently, tolerated a normal diet, and his expressive aphasia was improving.
Fig. 1. T2 MRI axial sequence with a left frontoparietal convexity (arrow) consistent with subdural hematoma causing mass effect and rightward shift of midline structures.
3. Discussion Osseointegrated bone conduction hearing systems (e.g., Baha) have been used clinically for more than 30 years, and worldwide on more than 100,000 patients. Osseointegrated systems have been used to secure auricular prostheses for decades with FDA approval since 1985 [3,4]. They have been shown to have an excellent safety profile and lead to improvements in quality of life [1]. They have a low rate of complications (4–6%), with skin breakdown and skin irritation being the most common [1,5,6]. Despite the overall favorable safety profile, there have been rare case reports of intra-cranial complications associated with temporal bone osseointegrated systems. Reported intra-cranial complications include sigmoid sinus thrombosis, temporal lobe abscess, and epidural hematoma [2,7,8]. We are unaware of previous reports of subdural hemorrhage from removal of osseointegrated systems. We have commonly placed osseointegrated devices; however, it is rare for us to remove these implants. Due to protracted site irritation, failure of antibiotics and local wound cares, and parental desire to remove the infected implant, removal was indicated. This case highlights a serious complication of placement/removal of auricular prosthesis osseointegrated implant. Awareness and understanding of this potential complication may provide assistance to those individuals that perform these procedures. Patients with irritation or infection around implant sites should be managed with the least invasive modality possible. In this case, our patient was treated with wound cares and antibiotics prior to any operative intervention. The first operative treatment was to remove the abutment and place healing caps, it was not until these interventions failed that we considered removal of the implant. There are several possible explanations for the development of the subdural hematoma in this patient. First, when the implant was initially inserted, it may have penetrated the dura and/or injured the vein. Alternatively, the implant may have eroded through the dura and/or vein over time with brain and skull growth. Removal of such an implant could then have caused acute injury to the vein. Finally, surgical instruments used to remove the implant may have resulted in traumatic entry into previously intact dura and/or vein. Skull thickness during development is variable and as such mastoid osseointegrated systems are FDA approved for children 5 years of age and older [9,10], but frequently are implanted at an earlier age due to the significant benefit that children receive from these implants when compared to non-surgical hearing aids [11] We obtain CT scans of the temporal bone as standard practice to assess temporal bone for adequate thickness prior to implantation [5]. There were no findings on the CT in this case to suggest placement would be challenging, additionally, there were no complications or excessive bleeding with either the first or second stage procedure to suggest injury of the dura or underlying vasculature. Although not obtained in this patient, consideration of an additional CT scan prior to device removal may be warranted. An additional CT scan can demonstrate intracranial extension of a device. This is illustrated by the post-operative head CT in this case which demonstrates the right implant traversing the squamous portion of the temporal bone (Fig. 2). However, in young children, presumption of device proximity to underlying dura would be recommended. This case also emphasizes the need for intra-operative vigilance during removal of osseo-integrated implants and acknowledgement of the potential of serious intracranial complications with this procedure. Based on this case, and discussion following, our surgical approach for any future device removal would include performing a larger (1–2 cm) craniotomy initially when removing the implant to provide better exposure and allow earlier identification of intracranial structures and injury. Additionally, this procedure should be performed in a setting with neurosurgical support readily available.
Please cite this article in press as: B.G. Nichols, et al., Subdural hematoma – a rare complication of removal of osseointegrated auricular prosthesis retention system, Int. J. Pediatr. Otorhinolaryngol. (2014), http://dx.doi.org/10.1016/j.ijporl.2014.05.016
G Model PEDOT 7135 No. of Pages 3
B.G. Nichols et al. / International Journal of Pediatric Otorhinolaryngology xxx (2014) xxx–xxx
3
during implantation or removal and require rapid recognition and response to mitigate poor outcomes. References
Fig. 2. CT scan without contrast of the head demonstrating the intracranial position of right ear implant (arrow).
In this case, vigilant post-operative care with early recognition in the recovery room allowed prompt treatment, which was imperative to maximize the patient’s outcome. 4. Conclusion Implants in the mastoid area are an important aid for retention of auricular prostheses, but may have life-threatening intracranial consequences. Serious intra-cranial complications can occur
[1] H. Kievit, G.W. Verhage-Damen, K.J. Ingels, E.A. Mylanus, M.K. Hol, Long-term quality of life assessment in patients with auricular prostheses, J. Craniofac. Surg. 24 (2) (2013) 392–397. [2] B.W. Rotenberg, A.L. James, D. Fisher, et al., Establishment of a bone-anchored auricular prosthesis (BAAP) program, Int. J. Pediatr. Otorhinolaryngol. 66 (2002) 273–279. [3] A. Gaggl, H. Rainer, H. Scharfegger, D. Attelscheck, F.M. Chiari, Sigmoid and transverse sinus thrombosis caused by mastoid implant — case report, J. Craniomaxillofac. Surg. 32 (5) (2004) 324–329. [4] C.A. Dun, M.J. de Wolf, M.K. Hol, et al., Stability, survival, and tolerability of a novel Baha implant system: six-month data from a multicenter clinical investigation, Otol. Neurotol. 32 (6) (2011) 1001–1007. [5] G. Ricci, A. Della Volpe, M. Faralli, et al., Results and complications of the Baha system (bone-anchored hearing aid), Eur. Arch. Otorhinolaryngol. 267 (10) (2010) 1539–1545. [6] K.K. Hamming, T.W. Lund, T.A. Lander, J.D. Sidman, Complications and satisfaction with pediatric osseointegrated external ear prostheses, Laryngoscope 119 (2009) 1270–1273. [7] M. Scholz, H. Eufinger, A. Anders, et al., Intracerebral abscess after abutment change of a bone anchored hearing aid (BAHA), Otol. Neurotol. 24 (6) (2003) 896–899. [8] F.B. Mesfin, N.W. Perkins, C. Brook, D. Foyt, J.W. German, Epidural hematoma after typanomastoidectomy and bone-anchored hearing aid placement: case report, Neurosurgery 67 (2010) E1451–E1453. [9] P.A. Federspil, S.H. Tretbar, F.H. Böhlen, S. Rohde, S. Glaser, P.K. Plinkert, Measurement of skull bone thickness for bone-anchored hearing aids: an experimental study comparing both a novel ultrasound system (SonoPointer) and computed tomographic scanning to mechanical measurements, Otol. Neurotol. 31 (3) (2010) 440–446. [10] S. Roman, R. Nicollas, J.M. Triglia, Practice guidelines for bone-anchored hearing aids in children, Eur. Ann. Otorhinolaryngol. Head Neck Dis. 128 (5) (2011) 253–258. [11] N. Verstraeten, A.J. Zarowski, T. Somers, D. Riff, E.F. Offeciers, Comparison of the audiologic results obtained with the bone-anchored hearing aid attached to the headband, the testband and the “snap” abutment, Otol. Neurotol. 30 (2008) 70–75.
Please cite this article in press as: B.G. Nichols, et al., Subdural hematoma – a rare complication of removal of osseointegrated auricular prosthesis retention system, Int. J. Pediatr. Otorhinolaryngol. (2014), http://dx.doi.org/10.1016/j.ijporl.2014.05.016