Novel Insights from Clinical Practice Pediatr Neurosurg 2013;49:187–192 DOI: 10.1159/000358924
Received: April 17, 2013 Accepted after revision: January 9, 2014 Published online: April 3, 2014
Treatment of Cephalocranial Disproportion in Shunt-Induced Slit Ventricle Syndrome with Cranial Vault Distraction Osteogenesis Maria Helena N. de Lima Raymond J. Harshbarger Timothy M. George Dell Children’s Medical Center of Central Texas, Austin, Tex., USA
Established Facts • Traditional cranial vault expansion is a useful method to treat cephalocranial disproportion (CCD) related to slit ventricle syndrome (SVS). • Cranial vault distraction osteogenesis has been used to treat CCD in patients with multi-suture synostosis and single-suture synostosis.
Novel Insights • Cranial vault expansion via distraction osteogenesis should be considered as an option in older patients with CCD related to SVS.
Key Words Distraction osteogenesis · Slit ventricle syndrome · Cranial expansion · Cephalocranial disproportion · Cranial vault · Intracranial pressure · Ventriculoperitoneal shunt · Headaches · Craniofacial surgery
Abstract Background: Slit ventricle syndrome (SVS) is a known late complication of shunting procedures. Some patients develop cephalocranial disproportion (CCD) that will require surgical treatment to increase craniocerebral compliance. Methods: We performed cranial vault distraction osteogen-
esis to treat 2 teenage patients who presented with SVS, increased intracranial pressure and CCD. Bilateral temporo-parieto-occipital craniotomies were performed. Results: Both patients successfully completed distraction and consolidated without the need for bone grafting. Postoperatively, both patients showed an increase in intracranial and intraventricular volume, as well as decreased shunt revisions. One patient had improvement of her headaches, while the other continues to have chronic headaches. Conclusion: Distraction osteogenesis is an option to expand the cranial vault in older children with SVS and CCD, in which the traditional cranial vault expansion would be a challenge and may or may not provide adequate expansion. © 2014 S. Karger AG, Basel
© 2014 S. Karger AG, Basel 1016–2291/14/0493–0187$39.50/0 E-Mail [email protected] www.karger.com/pne
Timothy M. George, MD 1301 Barbara Jordan Blvd., Suite 307 Austin, TX 78723 (USA) E-Mail tmgeorge @ seton.org
Introduction
The combination of symptoms of increased intracranial pressure (ICP) and relatively small ventricles found in chronically shunted hydrocephalic patients is clinically defined as slit ventricle syndrome (SVS). SVS is a known complication of shunting procedures, and is related to excessive drainage of CSF and collapse of the lateral ventricles, which in turn causes intermittent obstruction of the shunt catheter. Usually, SVS arises several years after the placement of the shunt. The actual incidence of SVS is unknown, however, it is estimated to be from 1 to 37% of shunted children [1]. Premature closure of cranial sutures (craniosynostosis) has been related to shunting procedures, leading to cephalocranial disproportion (CCD) [2–4]. The surgical treatment of SVS has been divided into three main groups: (1) restoration of
CSF circulation or correction of impaired CSF absorbtion (placement of ventricular, lumboperitoneal shunts and third ventriculostomy); (2) modification of previously inserted shunts (removal, programming), and (3) increasing craniocerebral compliance in the presence of CCD (subtemporal craniectomy and cranial vault expansion) [1–3]. Procedures designed to expand the skull volume are usually reserved as final options for CCD in SVS. Surgical options in CCD range from unilateral subtemporal craniectomy [5] to bilateral subtemporal decompression [6], and direct cranial expansion, such as fronto-orbital advancement [7, 8], suturectomy, posterior cranial vault expansion [8], supratentorial temporoparietal decompressive craniotomies [9]. We used distraction osteogenesis to expand the cranial volume in 2 patients with CCD as a consequence of SVS. Distraction osteogenesis has been
a
b
c
d
Fig. 1. Predistraction CT imaging (a, b).
Postconsolidation CT imaging shows good bony consolidation with increased intracranial and intraventricular volume.
188
Pediatr Neurosurg 2013;49:187–192 DOI: 10.1159/000358924
de Lima/Harshbarger/George
described for use in the cranial vault since 2008 [10], and it has been chiefly used in syndromic patients with multisuture synostosis and patients with single-suture synostosis [10–12].
Case Reports Two patients, age 14 and 16 years, who had been shunted chronically, developed intractable SVS and CCD, and presented with increased ICP on monitoring. Each underwent posterior cranial vault expansion via distraction osteogenesis. They both have had a follow-up period of at least 1 year.
Case 1 A female twin was born prematurely at 26 weeks of gestation. At 3 months of age she underwent her first ventriculoperitoneal shunt placement as a treatment for hydrocephalus post-grade II intraventricular hemorrhage. At the age of 4 years, she underwent a traditional cranial vault expansion for CCD. From the initial shunt placement until the age of 15 years, she underwent 20 shunt revisions. The patient had a history of loculate and encysted hydrocephalus, necessitating three ventricular catheters. She presented at our clinic with symptoms of chronic headaches, occasional absence seizures, upgaze palsy and slit-like ventricles on brain imaging. She underwent 11 additional shunt revisions over the next year. Findings at the shunt revisions included: one or more of the catheters had become occluded. At each revision, imaging revealed minimal change in ventricular size. Multiple episodes of ICP monitoring
a
b
c
d
Fig. 2. Preoperative (a, b) and 4 months postoperative (c, d) CT scans obtained
from patient 2 showing an increase in intracranial and intraventricular volume.
Treatment of Cephalocranial Disproportion in SVS with Distraction
Pediatr Neurosurg 2013;49:187–192 DOI: 10.1159/000358924
189
Fig. 3. a Cranial distractor (KLS Martin Group). b Side view of the device showing
L-shaped footplates for optimal functionality and device removal.
a
b
Fig. 4. Postoperative CT scans (three-dimensional reconstruction) obtained 48 h after the operation in patient 2
demonstrating the osteotomies and distractor device vector.
persistently demonstrated increased ICP. At the age of 16, she was treated with posterior cranial vault expansion via distraction osteogenesis. After a 7-day latency period, 0.9 mm/day of distraction was performed with a total of 18 mm per side. After a consolidation period of 3.5 months the distractors were removed. During the distraction period, one distractor failed and was replaced. Post-consolidation brain imaging showed an increase in intracranial volume and intraventricular volume (fig. 1). After cranial vault distraction osteogenesis, shunt catheter dependency was reduced from the original necessity of three ventricular catheters to one. After 14 months of follow-up, the patient continued to have symptoms of chronic headaches, however, the number of shunt revisions has decreased from 11 to 4 per year. Case 2 A female patient underwent her first ventriculoperitoneal shunt placement at 4 months of age as a treatment for hydrocephalus after bacterial meningitis at 3.5 months of age. She was asymptomatic until the age of 8 years, when she started developing symptoms of SVS such as chronic headaches, occasional upgaze palsy, lethargy, and concentration issues. She also presented with slit ventricles on brain imaging. By the age of 14 years, she had undergone 18 shunt revisions for continued symptoms of SVS. An increase in ICP was demonstrated by ICP monitoring. At 14 years of age she underwent posterior cranial vault expansion distraction osteogenesis. After a 10-day latency period, 1 mm/day of distraction was performed with a total of 17.5 mm
190
Pediatr Neurosurg 2013;49:187–192 DOI: 10.1159/000358924
per side. The consolidation period was 3 months, after which distractors were removed. During the distraction period, she suffered superficial infection at the distraction sites, which was successfully treated with oral antibiotics for 1 week. Postconsolidation CT showed an increase in intracranial volume and intraventricular volume (fig. 2). After 12 months of follow-up her symptoms of chronic headaches had resolved and she has not required any shunt revisions.
Operative Technique With the patient in prone position, a zigzag coronal incision was made. The dissection was then carried to the subgaleal plane, subgaleal and pericranial flaps were elevated separately. Once the cranium was fully exposed, the temporalis muscle was taken down. Bilateral temporo-parieto-occipital osteotomies were marked out and performed. Two cranial distractors (KLS Martin Group, Jacksonville, Fla., USA) were placed, one into each osteotomy, just posterior to the vertex, anterior to the lambdoid suture so that the vector of distraction was lateral. The devices were designed specifically for cranial distraction osteogenesis, in that they are low profile (to prevent scalp exposure), and the footplates have bone contact points, but allow for easier removal. Hinges were built into the footplates (to allow for minor vector competition when more than one device is used; fig. 3). At the anterior aspect of the osteotomies, a titanium microplate was placed to act as a hinge during distraction (fig. 4). Two suction drains were left and the wound was closed in layers.
de Lima/Harshbarger/George
Discussion
In patients with intractable SVS associated with CCD, cranial vault expansion has been used [8]. Patients who undergo expansion are typically beyond the age when spontaneous bone formation can occur within surgically created gaps. Therefore, during a traditional cranial vault expansion procedure, bone grafts would typically be required, lengthening the surgery, and necessitating a donor site. Cranial vault expansion via distraction osteogenesis has been described as a method to treat CCD. It is a viable technique for achieving expansion without the need for additional bone grafting. Since its first reports, it has been used predominantly for infants with single- and multi-suture synostosis [10–12]. Distraction osteogenesis of the cranial vault has several advantages: (1) It is an adjustable process; the patient can be reevaluated during distraction with a new CT or new measure of ICP, and distraction can be continued if expansion was insufficient. (2) It permits greater levels of expansion, since this technique is not limited by the scalp closure, especially in patients with a tight skin envelope. (3) With the gradual movement of the osteotomized segments, bridging bone is formed, and there is a smaller potential of leaving bony defects. Therefore, there is no need for bone grafts. (4) The dura is kept attached to the bone segments, helping keeping those segments vascularized. This will reduce dead space and improve the healing process [12]. On the other hand, it has the disadvantages of: delaying the final result, requiring an additional procedure for removal of the distractors, and the potential for device-related complications. We have adapted cranial vault distraction osteogenesis for use in 2 patients with chronic shunt-related SVS and CCD, as well as increased ICP. The 2 patients in our series were teenagers when they presented with CCD and SVS. It is also noteworthy that they did not have an abnormal head shape. At this age a traditional cranial vault expansion is a challenging procedure due to the thickness of the skull and the unlikelihood of spontaneous bone formation within bony defects, and therefore, the need for bone grafting. For these reasons distraction osteogenesis of the posterior vault was chosen as the preferred method to expand their cranial vault. In these patients, cranial vault distraction osteogenesis was successfully completed. Both of these patients had adequate expansion of their cranial vault, evidenced by the CT and MRI. The clinical course for these 2 patients was Treatment of Cephalocranial Disproportion in SVS with Distraction
improved, both with decreased ICP and increased intracranial volume. The first patient’s increase in volume for her intracranial contents made her shunt management a more controllable process, with fewer admissions to the hospital, and decrease in the number of shunt catheters from three to one, but persistent chronic headaches. Because of the headaches, the patient underwent subsequent ICP monitoring that did not reveal increased ICP, along with repeated imaging revealing increased subarachnoid space and improved ventricular size. Due to these findings, we did not believe that the headaches were induced by increased ICP. Therefore, no further interventions, such as third ventriculostomy with or without lumboperitoneal shunting, were deemed appropriate. The second patient significantly improved her symptoms with the expansion, and no longer required any shunt revision or emergency room visits. One device-related complication occurred in the first patient. During the distraction period the distractor worm gear broke, requiring replacement. The device had been designed mainly for use in younger children, with a thinner cranium. A larger, stronger version of the first distractor was used in the second patient, without any device complications. The second patient had a minor complication related to a superficial infection at the distractor sites. It was easily treated with oral antibiotics for 1 week. Cranial vault distraction osteogenesis can be used to address the underlying problem in children that were shunted in infancy and underwent multiple shunt revisions, shunt removals, and other treatments for the SVS without success. These children usually present at an older age, with CCD and a thicker skull. These factors present a distinct challenge when attempting to increase the cranial vault volume adequately. A traditional cranial vault expansion would have inherent limitations, while the cranial vault distraction osteogenesis has the ability to give greater and more controlled expansion. One must be aware of the potential complications and limitations of this method, with appropriate indications and proper technique, good outcomes can be achieved.
Acknowledgments The authors would like to thank Mark A. Binning and Collin A. Hovinga.
Pediatr Neurosurg 2013;49:187–192 DOI: 10.1159/000358924
191
References 1 Di Rocco C: Is the slit ventricle syndrome always a slit ventricle syndrome? Childs Nerv Syst 1994;10:49–58. 2 Rekate H: The slit ventricle syndrome: advances based on technology and understanding. Pediatr Neurosurg 2004;40:259–263. 3 Olson S: The problematic slit ventricle syndrome: a review of the literature and proposed algorithm for treatment. Pediatr Neurosurg 2004;40:264–269. 4 Anderson H: Craniosynostosis as a complication after operation for hydrocephalus. Acta Paediatr Scand 1966;55:192–196. 5 Epstein FJ, Fleischer AS, Hochwald GM, Ransohoff J: Subtemporal craniectomy for recurrent shunt obstruction secondary to small ventricles. J Neurosurg 1974;41:29–31.
192
6 Roth J, Biyani N, Udayakumaran S, Xiao X, Friedman O, Beni-Adani L, Constantini S: Modified bilateral subtemporal decompression for resistant slit ventricle syndrome. Childs Nerv Syst 2011;27:101–110. 7 Albright AL, Tyler-Kabara E: Slit-ventricle syndrome secondary to shunt-induced suture ossification. Neurosurgery 2001;48:764–769. 8 Weinzweig J, Bartlett SP, Chen JC, Losee J, Sutton L, Duhaime A, Whitaker LA: Cranial vault expansion in the management of postshunt craniosynostosis and slit ventricle syndrome. Plast Reconstr Surg 2008; 122: 1171– 1180.
Pediatr Neurosurg 2013;49:187–192 DOI: 10.1159/000358924
9 Martínez-Lage JF, Vilar AR, Pérez-Espejo MA, Almagro M, Pedro JRS, Murcia MF: Shunt-related craniocerebral disproportion: treatment with cranial vault expanding procedures. Neurosurg Rev 2006;29:229–235. 10 White N, Evans M, Dover MS, Noons P, Solanki G, Nishikawa H: Posterior cranial vault expansion using distraction osteogenesis. Childs Nerv Syst 2009;25:231–236. 11 Lao WW, Denny AD: Internal distraction osteogenesis to correct symptomatic cephalocranial disproportion. Plast Reconstr Surg 2010;126:1677–1688. 12 Steinbacher DM, Skirpan J, Puchata J, Bartlett SP: Expansion of the posterior cranial vault using distraction osteogenesis. Plast Reconstr Surg 2011;127:792–801.
de Lima/Harshbarger/George
Copyright: S. Karger AG, Basel 2014. Reproduced with the permission of S. Karger AG, Basel. Further reproduction or distribution (electronic or otherwise) is prohibited without permission from the copyright holder.
Received: April 17, 2013 Accepted after revision: January 9, 2014 Published online: April 3, 2014
Treatment of Cephalocranial Disproportion in Shunt-Induced Slit Ventricle Syndrome with Cranial Vault Distraction Osteogenesis Maria Helena N. de Lima Raymond J. Harshbarger Timothy M. George Dell Children’s Medical Center of Central Texas, Austin, Tex., USA
Established Facts • Traditional cranial vault expansion is a useful method to treat cephalocranial disproportion (CCD) related to slit ventricle syndrome (SVS). • Cranial vault distraction osteogenesis has been used to treat CCD in patients with multi-suture synostosis and single-suture synostosis.
Novel Insights • Cranial vault expansion via distraction osteogenesis should be considered as an option in older patients with CCD related to SVS.
Key Words Distraction osteogenesis · Slit ventricle syndrome · Cranial expansion · Cephalocranial disproportion · Cranial vault · Intracranial pressure · Ventriculoperitoneal shunt · Headaches · Craniofacial surgery
Abstract Background: Slit ventricle syndrome (SVS) is a known late complication of shunting procedures. Some patients develop cephalocranial disproportion (CCD) that will require surgical treatment to increase craniocerebral compliance. Methods: We performed cranial vault distraction osteogen-
esis to treat 2 teenage patients who presented with SVS, increased intracranial pressure and CCD. Bilateral temporo-parieto-occipital craniotomies were performed. Results: Both patients successfully completed distraction and consolidated without the need for bone grafting. Postoperatively, both patients showed an increase in intracranial and intraventricular volume, as well as decreased shunt revisions. One patient had improvement of her headaches, while the other continues to have chronic headaches. Conclusion: Distraction osteogenesis is an option to expand the cranial vault in older children with SVS and CCD, in which the traditional cranial vault expansion would be a challenge and may or may not provide adequate expansion. © 2014 S. Karger AG, Basel
© 2014 S. Karger AG, Basel 1016–2291/14/0493–0187$39.50/0 E-Mail [email protected] www.karger.com/pne
Timothy M. George, MD 1301 Barbara Jordan Blvd., Suite 307 Austin, TX 78723 (USA) E-Mail tmgeorge @ seton.org
Introduction
The combination of symptoms of increased intracranial pressure (ICP) and relatively small ventricles found in chronically shunted hydrocephalic patients is clinically defined as slit ventricle syndrome (SVS). SVS is a known complication of shunting procedures, and is related to excessive drainage of CSF and collapse of the lateral ventricles, which in turn causes intermittent obstruction of the shunt catheter. Usually, SVS arises several years after the placement of the shunt. The actual incidence of SVS is unknown, however, it is estimated to be from 1 to 37% of shunted children [1]. Premature closure of cranial sutures (craniosynostosis) has been related to shunting procedures, leading to cephalocranial disproportion (CCD) [2–4]. The surgical treatment of SVS has been divided into three main groups: (1) restoration of
CSF circulation or correction of impaired CSF absorbtion (placement of ventricular, lumboperitoneal shunts and third ventriculostomy); (2) modification of previously inserted shunts (removal, programming), and (3) increasing craniocerebral compliance in the presence of CCD (subtemporal craniectomy and cranial vault expansion) [1–3]. Procedures designed to expand the skull volume are usually reserved as final options for CCD in SVS. Surgical options in CCD range from unilateral subtemporal craniectomy [5] to bilateral subtemporal decompression [6], and direct cranial expansion, such as fronto-orbital advancement [7, 8], suturectomy, posterior cranial vault expansion [8], supratentorial temporoparietal decompressive craniotomies [9]. We used distraction osteogenesis to expand the cranial volume in 2 patients with CCD as a consequence of SVS. Distraction osteogenesis has been
a
b
c
d
Fig. 1. Predistraction CT imaging (a, b).
Postconsolidation CT imaging shows good bony consolidation with increased intracranial and intraventricular volume.
188
Pediatr Neurosurg 2013;49:187–192 DOI: 10.1159/000358924
de Lima/Harshbarger/George
described for use in the cranial vault since 2008 [10], and it has been chiefly used in syndromic patients with multisuture synostosis and patients with single-suture synostosis [10–12].
Case Reports Two patients, age 14 and 16 years, who had been shunted chronically, developed intractable SVS and CCD, and presented with increased ICP on monitoring. Each underwent posterior cranial vault expansion via distraction osteogenesis. They both have had a follow-up period of at least 1 year.
Case 1 A female twin was born prematurely at 26 weeks of gestation. At 3 months of age she underwent her first ventriculoperitoneal shunt placement as a treatment for hydrocephalus post-grade II intraventricular hemorrhage. At the age of 4 years, she underwent a traditional cranial vault expansion for CCD. From the initial shunt placement until the age of 15 years, she underwent 20 shunt revisions. The patient had a history of loculate and encysted hydrocephalus, necessitating three ventricular catheters. She presented at our clinic with symptoms of chronic headaches, occasional absence seizures, upgaze palsy and slit-like ventricles on brain imaging. She underwent 11 additional shunt revisions over the next year. Findings at the shunt revisions included: one or more of the catheters had become occluded. At each revision, imaging revealed minimal change in ventricular size. Multiple episodes of ICP monitoring
a
b
c
d
Fig. 2. Preoperative (a, b) and 4 months postoperative (c, d) CT scans obtained
from patient 2 showing an increase in intracranial and intraventricular volume.
Treatment of Cephalocranial Disproportion in SVS with Distraction
Pediatr Neurosurg 2013;49:187–192 DOI: 10.1159/000358924
189
Fig. 3. a Cranial distractor (KLS Martin Group). b Side view of the device showing
L-shaped footplates for optimal functionality and device removal.
a
b
Fig. 4. Postoperative CT scans (three-dimensional reconstruction) obtained 48 h after the operation in patient 2
demonstrating the osteotomies and distractor device vector.
persistently demonstrated increased ICP. At the age of 16, she was treated with posterior cranial vault expansion via distraction osteogenesis. After a 7-day latency period, 0.9 mm/day of distraction was performed with a total of 18 mm per side. After a consolidation period of 3.5 months the distractors were removed. During the distraction period, one distractor failed and was replaced. Post-consolidation brain imaging showed an increase in intracranial volume and intraventricular volume (fig. 1). After cranial vault distraction osteogenesis, shunt catheter dependency was reduced from the original necessity of three ventricular catheters to one. After 14 months of follow-up, the patient continued to have symptoms of chronic headaches, however, the number of shunt revisions has decreased from 11 to 4 per year. Case 2 A female patient underwent her first ventriculoperitoneal shunt placement at 4 months of age as a treatment for hydrocephalus after bacterial meningitis at 3.5 months of age. She was asymptomatic until the age of 8 years, when she started developing symptoms of SVS such as chronic headaches, occasional upgaze palsy, lethargy, and concentration issues. She also presented with slit ventricles on brain imaging. By the age of 14 years, she had undergone 18 shunt revisions for continued symptoms of SVS. An increase in ICP was demonstrated by ICP monitoring. At 14 years of age she underwent posterior cranial vault expansion distraction osteogenesis. After a 10-day latency period, 1 mm/day of distraction was performed with a total of 17.5 mm
190
Pediatr Neurosurg 2013;49:187–192 DOI: 10.1159/000358924
per side. The consolidation period was 3 months, after which distractors were removed. During the distraction period, she suffered superficial infection at the distraction sites, which was successfully treated with oral antibiotics for 1 week. Postconsolidation CT showed an increase in intracranial volume and intraventricular volume (fig. 2). After 12 months of follow-up her symptoms of chronic headaches had resolved and she has not required any shunt revisions.
Operative Technique With the patient in prone position, a zigzag coronal incision was made. The dissection was then carried to the subgaleal plane, subgaleal and pericranial flaps were elevated separately. Once the cranium was fully exposed, the temporalis muscle was taken down. Bilateral temporo-parieto-occipital osteotomies were marked out and performed. Two cranial distractors (KLS Martin Group, Jacksonville, Fla., USA) were placed, one into each osteotomy, just posterior to the vertex, anterior to the lambdoid suture so that the vector of distraction was lateral. The devices were designed specifically for cranial distraction osteogenesis, in that they are low profile (to prevent scalp exposure), and the footplates have bone contact points, but allow for easier removal. Hinges were built into the footplates (to allow for minor vector competition when more than one device is used; fig. 3). At the anterior aspect of the osteotomies, a titanium microplate was placed to act as a hinge during distraction (fig. 4). Two suction drains were left and the wound was closed in layers.
de Lima/Harshbarger/George
Discussion
In patients with intractable SVS associated with CCD, cranial vault expansion has been used [8]. Patients who undergo expansion are typically beyond the age when spontaneous bone formation can occur within surgically created gaps. Therefore, during a traditional cranial vault expansion procedure, bone grafts would typically be required, lengthening the surgery, and necessitating a donor site. Cranial vault expansion via distraction osteogenesis has been described as a method to treat CCD. It is a viable technique for achieving expansion without the need for additional bone grafting. Since its first reports, it has been used predominantly for infants with single- and multi-suture synostosis [10–12]. Distraction osteogenesis of the cranial vault has several advantages: (1) It is an adjustable process; the patient can be reevaluated during distraction with a new CT or new measure of ICP, and distraction can be continued if expansion was insufficient. (2) It permits greater levels of expansion, since this technique is not limited by the scalp closure, especially in patients with a tight skin envelope. (3) With the gradual movement of the osteotomized segments, bridging bone is formed, and there is a smaller potential of leaving bony defects. Therefore, there is no need for bone grafts. (4) The dura is kept attached to the bone segments, helping keeping those segments vascularized. This will reduce dead space and improve the healing process [12]. On the other hand, it has the disadvantages of: delaying the final result, requiring an additional procedure for removal of the distractors, and the potential for device-related complications. We have adapted cranial vault distraction osteogenesis for use in 2 patients with chronic shunt-related SVS and CCD, as well as increased ICP. The 2 patients in our series were teenagers when they presented with CCD and SVS. It is also noteworthy that they did not have an abnormal head shape. At this age a traditional cranial vault expansion is a challenging procedure due to the thickness of the skull and the unlikelihood of spontaneous bone formation within bony defects, and therefore, the need for bone grafting. For these reasons distraction osteogenesis of the posterior vault was chosen as the preferred method to expand their cranial vault. In these patients, cranial vault distraction osteogenesis was successfully completed. Both of these patients had adequate expansion of their cranial vault, evidenced by the CT and MRI. The clinical course for these 2 patients was Treatment of Cephalocranial Disproportion in SVS with Distraction
improved, both with decreased ICP and increased intracranial volume. The first patient’s increase in volume for her intracranial contents made her shunt management a more controllable process, with fewer admissions to the hospital, and decrease in the number of shunt catheters from three to one, but persistent chronic headaches. Because of the headaches, the patient underwent subsequent ICP monitoring that did not reveal increased ICP, along with repeated imaging revealing increased subarachnoid space and improved ventricular size. Due to these findings, we did not believe that the headaches were induced by increased ICP. Therefore, no further interventions, such as third ventriculostomy with or without lumboperitoneal shunting, were deemed appropriate. The second patient significantly improved her symptoms with the expansion, and no longer required any shunt revision or emergency room visits. One device-related complication occurred in the first patient. During the distraction period the distractor worm gear broke, requiring replacement. The device had been designed mainly for use in younger children, with a thinner cranium. A larger, stronger version of the first distractor was used in the second patient, without any device complications. The second patient had a minor complication related to a superficial infection at the distractor sites. It was easily treated with oral antibiotics for 1 week. Cranial vault distraction osteogenesis can be used to address the underlying problem in children that were shunted in infancy and underwent multiple shunt revisions, shunt removals, and other treatments for the SVS without success. These children usually present at an older age, with CCD and a thicker skull. These factors present a distinct challenge when attempting to increase the cranial vault volume adequately. A traditional cranial vault expansion would have inherent limitations, while the cranial vault distraction osteogenesis has the ability to give greater and more controlled expansion. One must be aware of the potential complications and limitations of this method, with appropriate indications and proper technique, good outcomes can be achieved.
Acknowledgments The authors would like to thank Mark A. Binning and Collin A. Hovinga.
Pediatr Neurosurg 2013;49:187–192 DOI: 10.1159/000358924
191
References 1 Di Rocco C: Is the slit ventricle syndrome always a slit ventricle syndrome? Childs Nerv Syst 1994;10:49–58. 2 Rekate H: The slit ventricle syndrome: advances based on technology and understanding. Pediatr Neurosurg 2004;40:259–263. 3 Olson S: The problematic slit ventricle syndrome: a review of the literature and proposed algorithm for treatment. Pediatr Neurosurg 2004;40:264–269. 4 Anderson H: Craniosynostosis as a complication after operation for hydrocephalus. Acta Paediatr Scand 1966;55:192–196. 5 Epstein FJ, Fleischer AS, Hochwald GM, Ransohoff J: Subtemporal craniectomy for recurrent shunt obstruction secondary to small ventricles. J Neurosurg 1974;41:29–31.
192
6 Roth J, Biyani N, Udayakumaran S, Xiao X, Friedman O, Beni-Adani L, Constantini S: Modified bilateral subtemporal decompression for resistant slit ventricle syndrome. Childs Nerv Syst 2011;27:101–110. 7 Albright AL, Tyler-Kabara E: Slit-ventricle syndrome secondary to shunt-induced suture ossification. Neurosurgery 2001;48:764–769. 8 Weinzweig J, Bartlett SP, Chen JC, Losee J, Sutton L, Duhaime A, Whitaker LA: Cranial vault expansion in the management of postshunt craniosynostosis and slit ventricle syndrome. Plast Reconstr Surg 2008; 122: 1171– 1180.
Pediatr Neurosurg 2013;49:187–192 DOI: 10.1159/000358924
9 Martínez-Lage JF, Vilar AR, Pérez-Espejo MA, Almagro M, Pedro JRS, Murcia MF: Shunt-related craniocerebral disproportion: treatment with cranial vault expanding procedures. Neurosurg Rev 2006;29:229–235. 10 White N, Evans M, Dover MS, Noons P, Solanki G, Nishikawa H: Posterior cranial vault expansion using distraction osteogenesis. Childs Nerv Syst 2009;25:231–236. 11 Lao WW, Denny AD: Internal distraction osteogenesis to correct symptomatic cephalocranial disproportion. Plast Reconstr Surg 2010;126:1677–1688. 12 Steinbacher DM, Skirpan J, Puchata J, Bartlett SP: Expansion of the posterior cranial vault using distraction osteogenesis. Plast Reconstr Surg 2011;127:792–801.
de Lima/Harshbarger/George
Copyright: S. Karger AG, Basel 2014. Reproduced with the permission of S. Karger AG, Basel. Further reproduction or distribution (electronic or otherwise) is prohibited without permission from the copyright holder.
