American Journal of Neuroradiology 26:30-33, January 2005
© 2005 American Society of Neuroradiology
Case Report
SPINE
Percutaneous Treatment of Pediatric Aneurysmal Bone Cyst at C1: A Minimally Invasive Alternative: A Case Report
Ansaar T. Raia and
John J. Collinsb
a Department of Radiology, West Virginia University, Morgantown, WV
b Department of Neurosurgery, West Virginia University, Morgantown, WV
Address correspondence to Ansaar T. Rai, MD, Department of Radiology, West Virginia University, P.O. Box 9235, Morgantown, WV 26506-9235
 |
Abstract
|
|---|
Summary: An 11-year-old girl presenting with neck pain was diagnosed
as having an aneurysmal bone cyst involving the posterior arch
of C1. Minimally invasive treatment was performed with percutaneous
injections of calcitonin and methylprednisolone. Two injections
separated in time by 2 months were performed with complete sclerosis
and ossification of the cyst over a period of 6 months. Such
percutaneous sclerosis offers an important primary therapeutic
option or an adjunct to surgery of these otherwise vascular
cystic masses and should be contemplated as the initial step
in the treatment of these benign tumors, especially those in
the spine where surgical treatment can involve complex resection
and fixation procedures.
 |
Introduction
|
|---|
Aneurysmal bone cysts are expansile lytic bone lesions. The
radiographic appearance of these lesions has been well documented
on conventional radiographs, CT scans, and MR images. Numerous
cases of pediatric aneurysm bone cysts affecting the spine have
been reported (
1
3). Treatment of these lesions typically
involves resection and curettage (
4
6). Other strategies
have included radiation therapy (
7) and sclerotherapy (
8). Angiographic
findings of these lesions and preoperative embolization have
been reported (
9,
10).
The following is a case report discussing the presentation, imaging, and treatment of an 11-year-old girl with an aneurysmal bone cyst at the posterior arch of C1.
 |
Case History
|
|---|
An 11-year-old girl presented with a 4-year history of increasing
neck pain and headaches. Her neurologic examination in the clinic
was normal. MR imaging showed an expansile lytic mass in the
posterior arch of C1 with a predominantly fluid signal intensity
and one or two small fluid-fluid levels. A thin-section CT revealed
an expanded C1 lamina with thin eggshell cortical margin and
small internal septation (
Fig 1). The thin bony margin was causing
some narrowing of the spinal canal. Radiographic diagnosis of
aneurysmal bone cyst was entertained, with other possibilities
such as osteoblastoma considered less likely.
Because there was no neurologic compromise and no cervical spine instability, surgical excision and associated spine fixation was deemed unnecessary. The more traditional interventional radiology procedure of particle embolization was also excluded because of the additional risks in the upper cervical region of vertebrobasilar and spinal arterial embolization. An initial attempt at percutaneous ablation of the cyst was considered a reasonable minimally invasive alternative.
The percutaneous procedure was performed under general endotracheal anesthesia. Under CT guidance, a coaxial biopsy needle was passed through the expanded outer cortex into the cystic mass (Fig 2). Four milliliters of blood were easily aspirated. A core specimen of the deeper wall of the cyst was obtained without discernable osseous tissue. The easy return of blood reinforced the diagnosis of an aneurysmal bone cyst. A mixture of 200 IU of calcitonin and 125 mg of methylpredisone was gently injected into the aneurysmal bone cyst. Finally, DBX bone putty (Dentsply Friadent Ceramed, Lakewood, CO) was injected on the outer aspect of the puncture site in the cortex.
The patient had significant symptomatic relief after the injection, lasting for about 2 months with some return in pain after that. A second similar intralesional injection was performed. A CT scan at that time showed increased sclerosis within the cyst, which indicated response to treatment (Fig 3). The patient had continued improvement of her neck pain with a 6-month follow-up CT scan showing complete ossification of the aneurysmal bone cyst (Fig 4). She did have recurrence of some of her pain, especially in the occipital region, and her occipital neuralgia was presumed to be secondary to mass effect and compression against upper cervical nerve roots by the now ossified cyst. Laminectomy and excision of the aneurysmal bone cyst was performed. Final pathologic diagnosis was consistent with aneurysmal bone cyst wall. Over the next month or so, her neck pain and upper cervical radiculopathy resolved.

View larger version (83K):
[in this window]
[in a new window]
|
FIG 3. Axial (A) and sagittal (B) reformatted images 2 months after the first intralesional injection show sclerosis developing along the margins of the aneurysmal bone cyst.
| |

View larger version (145K):
[in this window]
[in a new window]
|
FIG 4. Thin-section axial images about 6 months after the first injection show near-complete sclerosis.
| |
 |
Discussion
|
|---|
Surgical treatment of spinal aneurysmal bone cysts, which can
be very vascular, is technically challenging involving resection
and curettage and spine fixation. These procedures carry the
risk of significant blood loss, postoperative spinal deformity
and the possibility of recurrence (
1). Percutaneous intralesional
injections offer the least invasive initial therapeutic option
with more invasive surgical or endovascular strategies (
3,
10,
11) reserved for resistant lesions. In this case, since the
aneurysmal bone cyst involved the posterior arch of C1, the
vascular supply would have likely been from either or both of
the verterbral arteries with possibly some feeders from the
external carotid system. Embolization of any feeders arising
from the vertebral arteries carry the risk of inadvertent intracranial
and spinal artery embolization with potentially devastating
complications. In this case, because of the patients
young age, the location of the lesion, the complex spine surgery
involved and the risks of preoperative embolization, it was
decided to start with the least invasive and complex procedure
(percuatneous ablation) with embolization and surgery as an
alternative if the initial treatment failed. Placement of a
biopsy needle under CT guidance is relatively safe as long as
the cortical margin toward the spinal canal is not breached.
Needle insertion should be planned in such a way that any potential
bleeding should not compromise the spinal canal. Calcitonin
inhibitis osteoclastic activity and promotes trabecular bone
formation. Methylprednisolone has an antiangiogenesis effect.
The procedure we chose has been previously described (
12,
13).
In our case there was fairly rapid sclerosis and stabilization
of the lesion. Surgery performed for persistence radicular symptoms
was relatively straight forward with partial laminectomy without
the need for occipitocervical fixation and with minimal blood
loss.
 |
Conclusion
|
|---|
Image guided percutaneous sclerosis of spinal aneurysmal bone
cysts offers a relatively safe, simple and minimally invasive
option either as primary treatment or as an adjunct to surgery.
 |
References
|
|---|
- Seller K, Jager M, Kramer R, et al. Occurrence of a segmental kyphosis after laminectomy of C2 for an aneurysmatic bone cysts: course and treatment strategy. Z Orthop Ihre Grenzgeb 2004;142:8387[Medline]
- Arlet V, Rigault P, Padovani JP, et al. Aneurysmal bone cysts in children: study of 28 cases. Rev Chir Orthop Reparatrice Appar Mot 1987;73:337348[Medline]
- Dekeuwer P, Odent T, Cadilhac C, et al. Aneurysmal bone cyst of the spine in children: a 9-year follow-up of 7 cases and review of the literature. Rev Chir Orthop Reparatrice Appar Mot 2003;89:97106[Medline]
- Banczerowski P, Lipoth L, Vajda J, et al. Surgery of ventral intradural midline cervical spinal pathologies via anterior cervical approach: our experience. Ideggyogy Sz 2003;56:115118[Medline]
- Boriani S, De Lure F, Campanacci L, et al. Aneurysmal bone cyst of the mobile spine: report on 41 cases. Spine 2001;26:2735[Medline]
- Yousri B, Aboumaarouf M, El Andaloussi M. Aneurismal bone cyst in children: 17 cases. Rev Chir Orthop Reparatrice Appar Mot 2003;89(4):338345
- Feigenberg SJ, Marcus RB, Zlotecki R, et al. Megavoltage radiotherapy for aneurysmal bone cysts. Int J Radiat Oncol Biol Phys 2001;49:12431247[Medline]
- Dubois J, Chigot V, Grimard G, et al. Sclerotherapy in aneurysmal bone cysts in children: a review of 17 cases. Pediatr Radiol 2003;33:365372[Medline]
- DeRosa GP, Graziano GP, Scott J. Arterial embolization of aneurysmal bone cyst of the lumbar spine: a report of two cases. J Bone Joint Surg Am 1990;72:777780[Free Full Text]
- De Cristofaro R, Biagini R, Boriani S, et al. Selective arterial embolization in the treatment of aneurysmal bone cyst and angioma of bone. Skeletal Radiol 1992;21:523527[Medline]
- de Kleuver M, van der Heul RO, Veraart BE. Aneurysmal bone cyst of the spine: 31 cases and the importance of the surgical approach. J Pediatr Orthop B 1998;7:286292[Medline]
- Gladden ML Jr, Gillingham B, Hennrikus W, et al. Aneurysmal bone cyst of the first cervical vertebrae in a child treated with percutaneous intralesional injection of calcitonin and methylprednisolone: a case report. Spine 2000;25:527530; discussion 531[Medline]
- Szendroi M, et al. Calcitonin therapy of aneurysmal bone cysts. J Cancer Res Clin Oncol 1992;119:6165[Medline]
Received April 27, 2004;
accepted after revision May 6, 2004.