Intramedullary spinal cord tumor resection

The authors present a case of a 27-year-old patient who presented with spastic gait and worsening difficulty walking over a 6 month period. Spinal MR imaging revealed a heterogeneously enhancing intramedullary spinal cord tumor (IMSCT) with associated syrinx in the cervical spine. The lesion was resected through posterior en bloc laminotomy, durotomy, and microscopic resection of the intramedullary component followed by laminoplasty reconstruction. Surgical resections with a goal of gross total resection can significantly improve overall survival and progression free survival in patients with low-grade IMSCT. The procedure is presented in an edited, high-definition format with accompanying narrative. The video can be found here: http://youtu.be/Ui9bn82PtP8 .

Subependymoma: clinical features and surgical outcomes

OBJECTIVE

Subependymomas are rare, indolent neoplasms that have been described in the brain and the spinal cord. The purpose of this study is to report the clinical and radiolographic features, and surgical outcomes of this entity.

METHODS

Twenty-six patients with pathologically-verified subependymomas were treated from 1990 through 2009, with a mean follow-up of 39 months. The clinical and radiological records were reviewed and outcomes analyzed.

RESULTS

There were 15 fourth ventricle tumors, 6 lateral ventricle tumors, and 5 spinal tumors. For the intracranial tumors, headaches, changes in vision, and difficulties with balance were the most common symptoms. Most tumors were heterogeneously enhancing and hypointense or isointense to gray matter on T1-imaging and hyperintense on T2-imaging. All patients with tumors in the fourth ventricle underwent a suboccipital craniotomy and seven patients received an additional C1 laminectomy. Patients with lateral ventricular tumors underwent craniotomy with primarily a transcallosal resection. Patients with spinal tumors underwent laminectomy with intramedullary tumor resection. All tumors were resected employing microsurgical techniques. Overall, six patients had a sub-total resection. No recurrence of tumor or symptoms was noted at last follow-up for any patient, suggesting that maximal safe resection is often sufficient to provide symptomatic relief. Three patients had long-term complications from surgery. Tumor location was not associated with age at presentation, resection achieved, or development of complications.

CONCLUSIONS

Subependymomas are indolent tumors that when symptomatic can present with cerebrospinal fluid (CSF) obstructive symptoms in the brain and myelopathy in the spinal cord. There is no one symptom diagnostic for subependymomas. Surgical treatment can provide long term tumor control.

Vein of Galen malformations: epidemiology, clinical presentations, management

The vein of Galen aneurysmal malformation is a congenital vascular malformation that comprises 30% of the pediatric vascular and 1% of all pediatric congenital anomalies. Treatment is dependent on the timing of presentation and clinical manifestations. With the development of endovascular techniques, treatment paradigms have changed and clinical outcomes have significantly improved. In this article, the developmental embryology, clinical features and pathophysiology, diagnostic workup, and management strategies are reviewed.

Animal model of intramedullary spinal cord glioma using human glioblastoma multiforme neurospheres

Object

Advances in the diagnosis and management of patients with spinal cord tumors have been limited because of the rarity of the disease and the limitations of current animal models for spinal cord glioma. The ideal spinal cord tumor model would possess a number of characteristics, including the use of human glioma cells that capture the growth pattern and local invasive nature of their human counterpart. In this study, the authors' goal was to develop a novel spinal cord tumor model using a human neurosphere cell line.

Methods

Eighteen female athymic rats were randomized into 3 experimental groups. Animals in the first group (6 rats) received a 3-ml intramedullary injection containing DMEM and were used as controls. Animals in the second group (6 rats) received a 3-ml intramedullary injection containing 100,000 glioblastoma multiforme (GBM) neurosphere cells in 3 ml DMEM. Animals in the third group (6 rats) received a 3-ml intramedullary injection containing 9L gliosarcoma cells in 3 ml DMEM. Functional testing of hindlimb strength was assessed using the Basso-Beattie-Bresnahan (BBB) scale. Once the functional BBB score of an animal was less than or equal to 5 (slight movement of 2 joints and extensive movement of the third), euthanasia was performed.

Results

Animals in the GBM neurosphere group had a mean survival of 33.3 ± 2.0 days, which was approximately twice as long as animals in the 9L gliosarcoma group (16.3 ± 2.3 days). There was a significant difference between survival of the GBM neurosphere and 9L gliosarcoma groups (p < 0.001). None of the control animals died (p < 0.001 for GBM neurosphere group vs controls and 9L vs controls). Histopathological examination of the rats injected with 9L gliosarcoma revealed that all animals developed highly cellular, well-circumscribed lesions causing compression of the surrounding tissue, with minimal invasion of the surrounding gray and white matter. Histopathological examination of animals injected with GBM neurospheres revealed that all animals developed infiltrative lesions with a high degree of white and gray matter invasion along with areas of necrosis.

Conclusions

The authors have established a novel animal model of spinal cord glioma using neurospheres derived from human GBM. When injected into the spinal cords of athymic nude rats, neurospheres gave rise to infiltrative, actively proliferating tumors that were histologically identical to spinal cord glioma in humans. On the basis of their results, the authors conclude that this is a reproducible animal model of high-grade spinal cord glioma based on a human GBM neurosphere line. This model represents an improvement over other models using nonhuman glioma cell lines. Novel therapeutic strategies can be readily evaluated using this model.

"Colossal" breakthrough: the callosal puncture as a precursor to third ventriculostomy

BACKGROUND

In 1908, Anton and von Bramann proposed the Balkenstich method, a corpus callosum puncture which created a communication between the ventricle and subarachnoid space. This method offered the benefit of providing continuous CSF diversion without the implantation of cannula or other shunting devices, yet it received only slight reference in the literature of the time. It remained a novel and perhaps underutilized approach at the time Cushing began expanding his neurosurgical practice at the Johns Hopkins Hospital.

MATERIALS AND METHODS

Following IRB approval, and through the courtesy of the Alan Mason Chesney Archives, the surgical records of the Johns Hopkins Hospital for the period 1896-1912 were reviewed. Patients operated upon by Harvey Cushing were selected.

RESULTS

7 patients underwent puncture of the corpus callosum for treatment of hydrocephalus. 6 patients were treated for obstructive hydrocephalus secondary to presumed intracranial lesions. 1 patient was treated for congenital hydrocephalus.

CONCLUSION

The series reported here documents Cushing's early use of the corpus callosum puncture to divert CSF in patients with obstructive hydrocephalus secondary to intracranial tumors, as well as an attempt to use the procedure in a pediatric patient with congenital hydrocephalus. Notably, 3 patients developed new onset left-sided weakness post-operatively, possibly due to retraction injury upon the supplementary motor intra-operative manipulations.

A computed tomography-based feasibility study of translaminar screw placement in the pediatric thoracic spine

OBJECT

Translaminar screws (TLSs) were originally described as a safer alternative to pedicle and transarticular screw placement at C-2 in adult patients. More recently, TLSs have been used in both the cervical and thoracic spine of pediatric patients as a primary fixation technique and as a bailout procedure when dysplastic pedicle morphology prohibits safe pedicle screw placement. Although authors have reported the anatomical characteristics of the cervical and thoracic lamina in adults as well as those of the cervical lamina in pediatric patients, no such data exist to guide safe TLS placement in the thoracic spine of the pediatric population. The goal of this study was to report the anatomical feasibility of TLS placement in the thoracic spine of pediatric patients.

METHODS

Fifty-two patients (26 males and 26 females), with an average age of 9.5 ± 4.8 years, were selected by retrospective review of a trauma registry database after institutional review board approval. Study inclusion criteria were an age from 2 to 16 years, standardized axial bone-window CT images of the thoracic spine, and the absence of spinal trauma. For each thoracic lamina the following anatomical features were measured using eFilm Lite software: laminar width (outer cortical and cancellous), laminar height (LH), maximal screw length, and optimal screw trajectory. Patients were stratified by age (an age < 8 versus ≥ 8 years) and sex.

RESULTS

Collected data demonstrate the following general trends as one descends the thoracic spine from T-1 to T-12: 1) increasing laminar width to T-4 followed by a steady decrease to T-12, 2) increasing LH, 3) decreasing maximal screw length, and 4) increasing ideal screw trajectory angle. When stratified by age and sex, male patients older than 8 years of age had significantly larger laminae in terms of both width and height and allowed significantly longer screw placement at all thoracic levels compared with their female counterparts. Importantly, it was found that 78% of individual thoracic laminae, regardless of age or sex, could accept a 4.0-mm screw with 1.0 mm of clearance. As expected, when stratifying by age and sex, it was found that older male patients had the highest acceptance rates.

CONCLUSIONS

Data in the present study provide information regarding optimal TLS length, diameter, and trajectory for each thoracic spinal level in pediatric patients. Importantly, the data collected demonstrate no anatomical limitations within the pediatric thoracic spine to TLS instrumentation, although acceptance rates are lower for younger (< 8 years old) and/or female patients. Lastly, given the anatomical variation found in this study, CT scanning can be useful in the preoperative setting when planning TLS use in the thoracic spine of pediatric patients.

Posthemorrhagic hydrocephalus in preterm neonates: socioeconomic characteristics in a single-institution experience

Patients with posthemorrhagic hydrocephalus (PHH) from germinal matrix hemorrhage of prematurity often require numerous early interventions, as well as long-term follow-up care from pediatric neurosurgeons, which continues to place high demands on the existing workforce and pediatric health care system. There are established correlations between premature birth and low socioeconomic status. The aim of this study is to characterize the demographic profile and follow-up patterns in this subpopulation of surgically treated infants with PHH from prematurity.

METHODS

A retrospective analysis of the electronic patient records for a single institution, from 2007 to 2010, was performed. All patients who underwent neurosurgical intervention for the treatment of PHH were selected for further analysis. Data elements available within the records included patient demographic features, inpatient treatments and procedures, inpatient mortality rates, length of stay, and postoperative follow-up at the institution. Socioeconomic status was assessed using the median household income for the patient's zip code, as reported in the United States Census for the year 2000.

RESULTS

A total of 40 patients who underwent neurosurgical intervention for PHH at a single institution were identified. More patients were female (52.5%); the majority of patients were Black (57.5%). No patients were uninsured; most patients had public insurance (62.5%), and 65% were below the Maryland State median household income (USD 52,868). There were trends toward more frequent emergency room visits among those covered by public insurance and those below the state and national median house income, although differences were not statistically significant.

CONCLUSIONS

Our data indicate that the majority of patients fall within lower household income brackets, are born into households earning less than the statewide median household income, and are covered by public insurance. In light of the socioeconomic profile of the patient population reported here, these data may prove to be useful in preventative strategies aimed toward prematurity, PHH, and the ongoing treatment of hydrocephalus by pediatric neurosurgeons and other pediatric subspecialists.

Primary intramedullary spinal germ cell tumors

BACKGROUND

Intramedullary spinal germ cell tumors are rare lesions, with germinomas being the most common variant.

METHODS

To date, there have been 23 reports of primary intramedullary germ cell tumors described in the literature, the vast majority occurring in Japanese patients.

RESULTS

We present a case of a nonmetastatic intramedullary germ cell tumor in a 28-year-old Caucasian woman.

CONCLUSIONS

Characteristics of intramedullary germ cell tumors are summarized, and the current role for surgery and adjuvant radiation and chemotherapy are discussed.

Harvey Cushing and "birth hemorrhage": early pediatric neurosurgery at The Johns Hopkins Hospital

Of Harvey Cushing's many contributions to neurosurgery, one of the least documented is his early surgical intervention in children and his pioneering efforts to establish pediatric neurosurgery as a subspecialty. Between 1896 and 1912 Cushing conducted nearly 200 operations in children at The Johns Hopkins Hospital. A review of his records suggests that the advances he made in neurosurgery were significantly influenced by his experience with children. In this historical article, the authors describe Cushing's treatment of 6 children, in all of whom Cushing established a diagnosis of "birth hemorrhage." By reviewing Cushing's operative indications, techniques, and outcomes, the authors aim to understand the philosophy of his pediatric neurosurgical management and how this informed his development of neurosurgery as a new specialty.

Operative treatment for microcephaly secondary to craniosynostosis at the turn of the twentieth century

INTRODUCTION

Microcephaly has been described throughout history, and physicians in the nineteenth and early twentieth centuries struggled to identify the etiology of this condition in order to better treat it. In 1908, Cushing wrote in Surgery of the Head, in Keen's Surgery Its Principles and Practice, that the use of craniotomies for the treatment of microcephaly was a futile practice, with limited post-operative improvement that did not justify the operative risks.

METHODS

Following IRB approval, and through the courtesy of the Alan Mason Chesney Archives, the surgical files of the Johns Hopkins Hospital, from 1896 to 1912, were reviewed. A single case of operative treatment of microcephaly, performed 3 years after Cushing's published opinion on the procedure, was discovered and is described here.

RESULTS

In 1911, a 3-year-old girl from Florida presented with complaints of an "inability to walk" and "backward development." The diagnosis of microcephaly, possibly secondary to craniosynostosis, was made. Cushing operated upon her twice, performing bilateral decompressive craniotomies in a two-stage operation, without excision of the synostosis. Post-operatively, he documented improvement in the child's condition and a resolution of some presenting symptoms.

CONCLUSIONS

Although Cushing published his disapproval of the use of craniotomies in the treatment of microcephaly in 1908, a review of his early surgical files demonstrates that this opinion was based on cases published in the literature, rather than his own operative experience. In 1911, he performed bilateral craniotomies in a 3-year-old patient with microcephaly and documented post-operative improvement in the patient's general condition.

Father of neurosurgery: Harvey Cushing's early experience with a pediatric brainstem glioma at the Johns Hopkins Hospital

OBJECT

The early 20th century posed several challenges in the diagnosis and surgical treatment of intracranial tumors. However, this was a time in which more information was becoming more readily available based on pathological examination and surgical case reports. Such early work was crucial in shaping the current understanding of the nervous system and in developing modern treatment strategies. An early historical overview of the diagnosis and surgical interventions in pediatric patients with brainstem gliomas has not been described. Furthermore, Dr. Harvey Cushing's contributions to this field have not been reported.

METHODS

Following institutional review board approval, and through the courtesy of the Alan Mason Chesney Archives, the authors reviewed the Johns Hopkins Hospital surgical files dating from 1896 to 1912.

RESULTS

The authors describe Cushing's early experience with a pediatric brainstem glioma during his time as a young attending physician at the Johns Hopkins Hospital. The case, presented in 1909, described the clinical events in a 15-year-old schoolgirl who presented with signs of a cerebellopontine lesion. A suboccipital exploration was performed by Cushing; his findings and surgical approach are described.

CONCLUSIONS

Harvey Cushing's early contributions to the field of pediatric neurosurgery, and to the operative treatment of pediatric brainstem gliomas have remained largely unknown. The case presented here represents the early work of the American "Father of Neurosurgery."

Infrasellar craniopharyngiomas: case report and review of the literature

Although craniopharyngiomas account for a large percentage of pediatric intracranial tumors, there is a bimodal age distribution. Most of these neoplasms are suprasellar or sellar in location. In this report we describe an unusual case of an infrasellar craniopharyngioma in a child. Only four previous cases of infrasellar craniopharyngiomas with no sellar involvement have been described. Infrasellar craniopharyngiomas are part of the continuum representing intracranial craniopharyngiomas and ameloblastomas of the jaw. A transnasal endoscopic biopsy was performed with a preliminary diagnosis of craniopharyngioma. The patient then underwent a radical resection of the infrasellar tumor via a subfrontal transbasal approach. This case illustrates a rare and unusual location for a craniopharyngioma. Craniopharyngiomas should be considered in the differential diagnosis of infrasellar neoplasms. Infrasellar craniopharyngiomas compromise part of the spectrum of tumors originating from enamel-forming neural crest cells.

Use of a minimally invasive tubular retraction system for deep-seated tumors in pediatric patients

OBJECT

Microsurgical removal is the preferred treatment for most deep-seated, intraaxial tumors in the pediatric population. The feasibility of surgery as an option has improved with advances in surgical technology and technique. Tubular retractors disperse retraction forces over a greater surface area than do conventional retractors, which can lower the risk of ischemic complications. The authors describe their experience utilizing a new tubular retractor system specifically designed for cranial applications in conjunction with frameless neuronavigation.

METHODS

The Vycor ViewSite retractor was used in 4 pediatric patients (ages 15 months and 9, 10, and 16 years) with deep-seated intraaxial tumors. The lesions included a papillary tumor of the pineal region, a low-grade astrocytoma in the occipital lobe, a dysembryoplastic neuroepithelial tumor arising from the basal ganglia, and an intraventricular low-grade glioma. The extent of white matter damage along the surgical trajectory (based on T2 or FLAIR and diffusion restriction/apparent diffusion coefficient signals) and the extent of resection were assessed on postoperative imaging.

RESULTS

Satisfactory resection or biopsy was achieved in all patients. A comparison of pre- and postoperative MR imaging studies revealed evidence of white matter damage along the surgical trajectory in 1 patient. None of the patients demonstrated new neurological deficits postoperatively.

CONCLUSIONS

Obtaining surgical access to deep-seated, intraaxial tumors is challenging. In this small series of pediatric patients, the combination of the ViewSite tubular retractor and frameless neuronavigation facilitated the surgical approach. The combination of these technologies adds to the armamentarium to safely approach tumors in deep locations.

Papillary tumor of the pineal region in a 15-month-old boy

The papillary tumor of the pineal region (PTPR) is a distinct entity that is particularly rare in the pediatric population. The authors document the youngest reported patient with this clinicopathological entity to date. A case of PTPR in a 15-month-old boy is described. Initially thought to be a tectal glioma, the tumor was later identified as a pineal region tumor after demonstrating growth on routine imaging. Diagnosis of PTPR was established by histopathological evaluation of biopsy samples, which revealed papillary, cystic, and solid tumor components. The patient's postoperative course was complicated by tumor growth despite several debulking procedures and chemotherapy, as well as persistent hydrocephalus requiring 2 endoscopic third ventriculostomies and eventual ventriculoperitoneal shunt placement. After a 15-month follow-up period, the patient has received proton-beam therapy and has a stable tumor size. The PTPR is a recently described tumor of the CNS that must be included in the differential diagnosis of pineal region masses. The biological behavior, prognosis, and appropriate treatment of PTPR have yet to be fully defined.

The genetic landscape of the childhood cancer medulloblastoma

Medulloblastoma (MB) is the most common malignant brain tumor of children. To identify the genetic alterations in this tumor type, we searched for copy number alterations using high-density microarrays and sequenced all known protein-coding genes and microRNA genes using Sanger sequencing in a set of 22 MBs. We found that, on average, each tumor had 11 gene alterations, fewer by a factor of 5 to 10 than in the adult solid tumors that have been sequenced to date. In addition to alterations in the Hedgehog and Wnt pathways, our analysis led to the discovery of genes not previously known to be altered in MBs. Most notably, inactivating mutations of the histone-lysine N-methyltransferase genes MLL2 or MLL3 were identified in 16% of MB patients. These results demonstrate key differences between the genetic landscapes of adult and childhood cancers, highlight dysregulation of developmental pathways as an important mechanism underlying MBs, and identify a role for a specific type of histone methylation in human tumorigenesis.

Harvey Cushing and early spinal dysraphism repair at Johns Hopkins Hospital

As neurological surgery began developing into a surgical subspecialty in the US at the turn of the 20th century, with Harvey Cushing at the forefront, the operative treatment of spinal dysraphism was refined with attempts to minimize complications. Following institutional approval, and through the courtesy of the Alan Mason Chesney Archives, the authors reviewed the Johns Hopkins Hospital surgical files from 1896 to 1912. Patients presenting with spinal dysraphism who underwent surgical intervention by Dr. Harvey Cushing were selected for further analysis. Ten patients presented for surgical intervention for spinal dysraphism, and 7 of these had concurrent hydrocephalus. The mean age of these patients was 5.8 months (range 1-14 months). The mean length of stay was 20.4 days. There were 6 inpatient deaths. At the time of last follow-up, 2 patients were well, 1 patient remained unimproved, and 1 patient (for whom no discharge outcome was available) had died. The cases described in detail offer insight into the breadth of Cushing's practice and the varied approaches he employed. The use of Faradic stimulation to assess nerve root function, the use of complex multilayered closures, and the creation of operative tables for combined treatment of hydrocephalus and spinal dysraphism illustrate Cushing's contributions to developing the field of pediatric neurosurgery.

"Groans less, seems more comfortable:" Harvey Cushing's redefinition of success in the operative treatment of pediatric intracranial lesions

BACKGROUND

Challenges to diagnosing and localizing intracranial lesions in pediatric patients were immense during the advent of neurosurgery. For patients with suspected intracranial tumors, but with negative findings on operation, there were few options. The role of palliative surgical interventions, from decompressive craniectomies to lumbar and ventricular punctures, is not well-represented in the literature during this early stage.

OBJECTIVE

To review Harvey Cushing's original surgical files and analyze his use of decompressive procedures in pediatric patients with suspected intracranial tumors, with negative findings during operative interventions.

METHODS

Following IRB approval, and through the courtesy of the Alan Mason Chesney Archives, we reviewed the Johns Hopkins Hospital surgical files from 1896 to 1912. Patients, ≤18 years old, presenting with suspected intracranial tumors, undergoing surgical intervention by Cushing, without discovery of intracranial pathology, were selected for further analysis.

RESULTS

Of the 23 pediatric patients selected, 17 were male. The mean age was 10.6 years. Cushing used three main operative approaches: infratentorial/suboccipital, subtemporal, and hemisphere flaps. Post-operative condition was improved in 13 and unchanged in three patients. Seven patients died during their inpatient stay. The mean time to follow-up was 34.79 months; the mean time to death was 11.9 months.

CONCLUSIONS

These examples illustrate Cushing's commitment to improving quality of life in patients, offering decompressive procedures, including craniectomies as well as cerebrospinal fluid drainage in the operating room and at the bedside, when attempts at localizing and resecting of suspected tumors were unsuccessful.

A computed tomography-based morphometric study of thoracic pedicle anatomy in a random United States trauma population

OBJECT

The objective of this study was to establish normative data for thoracic pedicle anatomy in the US adult population. To this end, CT scans chosen at random from an adult database were evaluated to determine the ideal pedicle screw (PS) length, diameter, trajectory, and starting point in the thoracic spine. The role of patient sex and side of screw placement were also assessed. The authors postulated that this information would be of value in guiding safe implant size and placement for surgeons in training.

METHODS

One hundred patients (50 males and 50 females) were selected via retrospective review of a hospital trauma registry database over a 6-month period. Patients included in the study were older than 18 years of age, had axial bone-window CT images of the thoracic spine, and had no evidence of spinal trauma. For each pedicle, the pedicle width, pedicle-rib width, estimated screw length, trajectory, and ideal entry point were measured using eFilm Lite software. Statistical analysis was performed using the Student t-test.

RESULTS

The shortest mean estimated PS length was at T-1 (33.9 ± 3.3 mm), and the longest was at T-9 (44.9 ± 4.4 mm). Pedicle screw length was significantly affected by patient sex; men could accommodate a PS from T1-12 a mean of 4.0 ± 1.0 mm longer than in women (p < 0.001). Pedicle width showed marked variation by spinal level, with T-4 (4.4 ± 1.1 mm) having the narrowest width and T-12 (8.3 ± 1.7 mm) having the widest. Pedicle width had an obvious affect on potential screw diameter; 65% of patients had a least 1 pedicle at T-4 that was < 5 mm in diameter and therefore would not accept a 4.0-mm screw with 1.0 mm of clearance, as compared with only 2% of patients with a similar status at T-12. Sex variation was also apparent, as thoracic pedicles from T-1 to T-12 were a mean of 1.4 ± 0.2 mm wider in men than in women (p < 0.001). The PS trajectory in the axial plane was measured, showing a marked decrease from T-1 to T-4, stabilization from T-5 to T-10, followed by a decrease at T11-12. When screw trajectory was stratified by side of placement, a mean of 1.7° ± 0.5° of increased medialization was required for ideal pedicle cannulation from T-3 to T-12 on the left as compared with the right side, presumably because of developmental changes in the vertebral body caused by the aorta (p < 0.05 for T3-12, except for T-5, where p = 0.051). The junction of the superior articular process, lamina, and the superior ridge of the transverse process was shown to be a conserved surface landmark for PS placement.

CONCLUSIONS

Preoperative CT evaluation is important in choosing PS length, diameter, trajectory, and entry point due to variation based on spinal level, patient sex, and side of placement. These data are valuable for resident and fellow training to guide the safe use of thoracic PSs.

The evolution of surgical management for craniosynostosis

Craniosynostosis, the premature closure of cranial sutures, has been known to exist for centuries, but modern surgical management has only emerged and evolved over the past 100 years. The success of surgery for this condition has been based on the recognition of scientific principles that dictate brain and cranial growth in early infancy and childhood. The evolution of strip craniectomies and suturectomies to extensive calvarial remodeling and endoscopic suturectomies has been driven by a growing understanding of how a prematurely fused cranial suture can affect the growth and shape of the entire skull. In this review, the authors discuss the early descriptions of craniosynostosis, describe the scientific principles upon which surgical intervention was based, and briefly summarize the eras of surgical management and their evolution to present day.

Spinal cord tethering following myelomeningocele repair

OBJECT

Symptom response to spinal cord untethering, and the impact of duraplasty and scoliosis on retethering, are poorly understood in tethering after myelomeningocele (MMC) repair. In this retrospective study, the authors examined the outcomes of children who developed first-time spinal cord tethering following MMC repair. The response of symptoms to untethering and the role of duraplasty and scoliosis in retethering are explored.

METHODS

The authors performed a review of 54 children with first-time symptomatic spinal cord tethering following MMC repair to determine the impact of untethering on symptoms, the impact of dural repair type on retethering, and the role of scoliosis on the prevalence and time to retethering.

RESULTS

The average patient age was 10.3 ± 4.9 years, and 44% were males. The most common presenting symptoms of tethered cord syndrome were urinary (87%), motor (80%), gait (78%), and sensory (61%) dysfunction. The average postoperative time to symptom improvement was 2.02 months for sensory symptoms, 3.21 months for pain, 3.50 months for urinary symptoms, and 4.48 months for motor symptoms, with sensory improvement occurring significantly earlier than motor improvement (p = 0.02). At last follow-up (an average of 47 months), motor symptoms were improved in 26%, maintained in 62%, and worsened in 11%; for sensory symptoms, these rates were 26%, 71%, and 3%, respectively; for pain, 28%, 65%, and 7%, respectively; and for urinary symptoms, 17%, 76%, and 7%, respectively. There was no difference in symptom response with type of dural repair (primary closure vs duraplasty). Symptomatic retethering occurred in 17 (31%) of 54 patients, but duration of symptoms, age at surgery, and type of dural repair were not associated with retethering. Scoliosis was not associated with an increased prevalence of retethering, but was associated with significantly earlier retethering (32.5 vs 61.1 months; p = 0.042) in patients who underwent additional untethering operations.

CONCLUSIONS

Symptomatic retethering is a common event after MMC repair. In the authors' experience, sensory improvements occur sooner than motor improvements following initial untethering. Symptom response rates were not altered by type of dural closure. Scoliosis was associated with significantly earlier retethering and should be kept in mind when caring for individuals who have had previous MMC repair.

The effect of spinal instrumentation on kinematics at the cervicothoracic junction: emphasis on soft-tissue response in an in vitro human cadaveric model

Object

Thoracic pedicle screw instrumentation is often indicated in the treatment of trauma, deformity, degenerative disease, and oncological processes. Although classic teaching for cervical spine constructs is to bridge the cervicothoracic junction (CTJ) when instrumenting in the lower cervical region, the indications for extending thoracic constructs into the cervical spine remain unclear. The goal of this study was to determine the role of ligamentous and facet capsule (FC) structures at the CTJ as they relate to stability above thoracic pedicle screw constructs.

Methods

A 6-degree-of-freedom spine simulator was used to test multidirectional range of motion (ROM) in 8 human cadaveric specimens at the C7–T1 segment. Flexion-extension, lateral bending, and axial rotation at the CTJ were tested in the intact condition, followed by T1–6 pedicle screw fixation to create a long lever arm inferior to the C7–T1 level. Multidirectional flexibility testing of the T1–6 pedicle screw construct was then sequentially performed after sectioning the C7–T1 supraspinous ligament/interspinous ligament (SSL/ISL) complex, followed by unilateral and bilateral FC disruption at C7–T1. Finally, each specimen was reconstructed using C5–T6 instrumented fixation and ROM testing at the CTJ performed as previously described.

Results

Whereas the application of a long-segment thoracic construct stopping at T-1 did not significantly increase flexion-extension peak total ROM at the supra-adjacent level, sectioning the SSL/ISL significantly increased flexibility at C7–T1, producing 35% more motion than in the intact condition (p < 0.05). Subsequent FC sectioning had little additional effect on ROM in flexion-extension. Surprisingly, the application of thoracic instrumentation had a stabilizing effect on the supra-adjacent C7–T1 segment in axial rotation, leading to a decrease in peak total ROM to 83% of the intact condition (p < 0.05). This is presumably due to interaction between the T-1 screw heads and titanium rods with the C7–T1 facet joints, thereby limiting axial rotation. Incremental destabilization served only to restore peak total ROM near the intact condition for this loading mode. In lateral bending, the application of thoracic instrumentation stopping at T-1, as well as SSL/ISL and FC disruption, demonstrated trends toward increased supraadjacent ROM; however, these trends did not reach statistical significance (p > 0.05).

Conclusions

When stopping thoracic constructs at T-1, care should be taken to preserve the SSL/ISL complex to avoid destabilization of the supra-adjacent CTJ, which may manifest clinically as proximal-junction kyphosis. In an analogous fashion, if a T-1 laminectomy is required for neural decompression or surgical access, consideration should be given to extending instrumentation into the cervical spine. Facet capsule disruption, as might be encountered during T-1 pedicle screw placement, may not be an acutely destabilizing event, due to the interaction of the C7–T1 facet joints with T-1 instrumentation.

Establishment of a human glioblastoma stemlike brainstem rodent tumor model

OBJECT

Diffuse brainstem tumors are the most difficult type of pediatric CNS malignancy to treat. These inoperable lesions are treated with radiation alone or in combination with chemotherapy, and the survival rate is less than 10%. It is therefore essential to develop a reliable animal model to screen new therapeutic agents for the treatment of this type of tumor.

METHODS

A multipotent human glioblastoma stemlike neurosphere line, 060919, was established from a surgically resected glioblastoma specimen; when cells were implanted intracranially into athymic nude mice, they formed invasive, vascular tumors that exhibited the features of glioblastoma. Ten female Fischer 344 rats received an injection of 75,000 F98 rat glioma cells and 10 female athymic nude rats received an injection of 75,000 060919 human glioblastoma stemlike cells in the pontine tegmentum of the brainstem. A control group of 5 female Fischer rats received an injection of saline in the same location as the animals in the tumor groups. Kaplan-Meier curves were generated for survival, and brains were processed postmortem for histopathological investigation.

RESULTS

Both F98 cells and 060919 cells grew in 100% of the animals injected. Median survival of animals injected with F98 was 15 days, consistent with the authors' previous reports on the establishment of the brainstem tumor model using the F98 rat glioma line. Median survival of animals injected with 060919 was 31 days. Histopathological analysis of the tumors confirmed the presence of brainstem lesions in animals that received brainstem injections of F98 and in animals that received brainstem injections of 060919. The 060919 brainstem tumors histologically resembled glioblastoma.

CONCLUSIONS

Tumor take and median survival were consistent for animals injected in the brainstem with either the established F98 rat glioma cell line or the 060919 human glioblastoma stemlike neurosphere line. Histopathological features of the 060919 brainstem tumors resembled glioblastoma. Establishment of this human glioblastoma stemlike brainstem animal model will improve the evaluation and identification of more efficacious agents for the treatment of high-grade brainstem tumors.