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Andrew Yew, Jon Kimball and Daniel C. Lu

Seroma formation following posterior cervical laminectomy and fusion is now recognized as a rare but significant risk. Previous reports have attributed the development of postoperative seromas to the use of recombinant bone morphogenetic protein–2 (rhBMP-2). Here the authors present the case of a 78-year-old female with a history of osteoporosis who developed delayed postoperative neck and shoulder pain following posterior cervical laminectomy and fusion utilizing only autograft bone and demineralized bone matrix (DBM) allograft. Postoperative MRI demonstrated normal hardware placement and a large epidural fluid collection that extended from C-4 to C-6. The patient underwent decompression and drainage of her sterile postoperative seroma. To the authors' knowledge, no case of seroma formation with the use of DBM has been previously reported. This case suggests that although rhBMP-2 is involved in the majority of postoperative seroma developments, other osteoinductive agents such as DBM can contribute to the development of a symptomatic seroma. This report presents an illustrative case study and reviews the current understanding of the development of and treatment for cervical seroma following posterior cervical laminectomy and fusion.

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Jon Kimball, Andrew Yew and Daniel C. Lu

Symptomatic disc herniation is a common indication for spinal operations. The open microscopic discectomy has been the traditional method of addressing this pathology, but minimally invasive techniques are increasingly popular.

Potential advantages of the MIS microdiscectomy approach include decreased muscle and soft tissue disruption, shorter length of stay and decreased postoperative pain. Here we demonstrate an MIS microdiscectomy on a 24-year-old female with a left L-4 and L-5 radiculopathy secondary to a large L4–5 disc herniation.

The video can be found here: http://youtu.be/aXyZ2FJMh2s.

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Jon Kimball, Andrew Yew, Ruth Getachew and Daniel C. Lu

Transforaminal lumbar interbody fusion (TLIF) was originally developed as a method for circumferential fusion via a single posterior approach and is now an extremely common procedure for the treatment of lumbar instability. More recently, minimally invasive techniques have been applied to this procedure with the goal of decreasing tissue disruption, blood loss and postoperative patient discomfort. Here we describe a minimally invasive tubular TLIF on a 60-year-old male with radiculopathy from an unstable L4–5 spondylolisthesis.

The video can be found here: http://youtu.be/0BbxQiUmtRc.

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Andrew Yew, Jon Kimball, Patrick Pezeshkian and Daniel C. Lu

Spinal metastatic lesions are the most common tumors encountered by spinal surgeons. As with procedures for degenerative disease, minimally invsive surgery techniques have been applied to minimize muscle and soft tissue destruction in procedures for tumor resection. Here, we present a 23-year-old female with radiculopathy and foot drop secondary to nerve root compression by epidural metastases from Ewing's sarcoma.

This patient had a history of previous resection and instrumentation as well as multiple rounds of chemotherapy and radiation that failed to control her disease. The patient presented with three weeks of radicular pain and foot drop that was continuing to worsen at the time of her operation. The decision was therefore made to perform a palliative resection and decompression for relief of her progressive symptoms. In this video, we demonstrate a palliative tumor debulking and nerve root decompression utilizing an MIS approach.

The video can be found here: http://youtu.be/tq4kbvKTebI.

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Winward Choy, Won Kim, Daniel Nagasawa, Stephanie Stramotas, Andrew Yew, Quinton Gopen, Andrew T. Parsa and Isaac Yang

Meningiomas are mostly benign, slow-growing tumors of the CNS that originate from arachnoidal cap cells. While monosomy 22 is the most frequent genetic abnormality found in meningiomas, a multitude of other aberrant chromosomal alterations, signaling pathways, and growth factors have been implicated in its pathogenesis. Losses on 22q12.2, a region encoding the tumor suppressor gene merlin, represent the most common genetic alterations in early meningioma formation. Malignant meningioma progression, however, is associated with more complex karyotypes and greater genetic instability. Cytogenetic studies of atypical and anaplastic meningiomas revealed gains and losses on chromosomes 9, 10, 14, and 18, with amplifications on chromosome 17. However, the specific gene targets in a majority of these chromosomal abnormalities remain elusive.

Studies have also implicated a myriad of aberrant signaling pathways involved with meningioma tumorigenesis, including those involved with proliferation, angiogenesis, and autocrine loops. Understanding these disrupted pathways will aid in deciphering the relationship between various genetic changes and their downstream effects on meningioma pathogenesis.

Despite advancements in our understanding of meningioma pathogenesis, the conventional treatments, including surgery, radiotherapy, and stereotactic radiosurgery, have remained largely stagnant. Surgery and radiation therapy are curative in the majority of lesions, yet treatment remains challenging for meningiomas that are recurrent, aggressive, or refractory to conventional treatments. Future therapies will include combinations of targeted molecular agents as a result of continued progress in the understanding of genetic and biological changes associated with meningiomas.

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Wajd N. Al-Holou, Andrew Y. Yew, Zackary E. Boomsaad, Hugh J. L. Garton, Karin M. Muraszko and Cormac O. Maher

Object

Arachnoid cysts are a frequent finding on intracranial imaging in children. The prevalence and natural history of these cysts are not well defined. The authors studied a large consecutive series of children undergoing MR imaging to better define both the MR imaging–demonstrated prevalence and behavior of these lesions over time.

Methods

The authors reviewed a consecutive series of 11,738 patients who were 18 years of age or younger and had undergone brain MR imaging at a single institution during an 11-year period. In the patients in whom intracranial arachnoid cysts were identified, clinical and demographic information was recorded and imaging characteristics, such as cyst size and location, were evaluated. Prevalence data were analyzed using univariate and multivariate logistic regression, linear regression, and ANOVA. All patients with sufficient data (repeat MR imaging studies as well as repeated clinical evaluation over at least 5 months) for a natural history analysis were identified. This group was assessed for any change in symptoms or imaging appearance during the follow-up interval.

Results

Three hundred nine arachnoid cysts (2.6% prevalence rate) were identified. There was an increased prevalence of arachnoid cysts in males (p < 0.000001). One hundred eleven patients met all criteria for inclusion in the natural history analysis. After a mean follow-up of 3.5 years, 11 arachnoid cysts increased in size, 13 decreased, and 87 remained stable. A younger age at presentation was significantly associated with cyst enlargement (p = 0.001) and the need for surgery (p = 0.05). No patient older than 4 years of age at the time of initial diagnosis had cyst enlargement, demonstrated new symptoms, or underwent surgical treatment.

Conclusions

Arachnoid cysts are a common incidental finding on intracranial imaging in pediatric patients. An older age at the time of presentation is associated with a lack of clinical or imaging changes over time.