Iatrogenic air embolism: pathoanatomy, thromboinflammation, endotheliopathy, and therapies.

Iatrogenic vascular air embolism is a relatively infrequent event but is associated with significant morbidity and mortality. These emboli can arise in many clinical settings such as neurosurgery, cardiac surgery, and liver transplantation, but more recently, endoscopy, hemodialysis, thoracentesis, tissue biopsy, angiography, and central and peripheral venous access and removal have overtaken surgery and trauma as significant causes of vascular air embolism. The true incidence may be greater since many of these air emboli are asymptomatic and frequently go undiagnosed or unreported. Due to the rarity of vascular air embolism and because of the many manifestations, diagnoses can be difficult and require immediate therapeutic intervention. An iatrogenic air embolism can result in both venous and arterial emboli whose anatomic locations dictate the clinical course. Most clinically significant iatrogenic air emboli are caused by arterial obstruction of small vessels because the pulmonary gas exchange filters the more frequent, smaller volume bubbles that gain access to the venous circulation. However, there is a subset of patients with venous air emboli caused by larger volumes of air who present with more protean manifestations. There have been significant gains in the understanding of the interactions of fluid dynamics, hemostasis, and inflammation caused by air emboli due to in vitro and in vivo studies on flow dynamics of bubbles in small vessels. Intensive research regarding the thromboinflammatory changes at the level of the endothelium has been described recently. The obstruction of vessels by air emboli causes immediate pathoanatomic and immunologic and thromboinflammatory responses at the level of the endothelium. In this review, we describe those immunologic and thromboinflammatory responses at the level of the endothelium as well as evaluate traditional and novel forms of therapy for this rare and often unrecognized clinical condition.

Viscoelastic Testing and Coagulopathy of Traumatic Brain Injury.

A unique coagulopathy often manifests following traumatic brain injury, leading the clinician down a difficult decision path on appropriate prophylaxis and therapy. Conventional coagulation assays-such as prothrombin time, partial thromboplastin time, and international normalized ratio-have historically been utilized to assess hemostasis and guide treatment following traumatic brain injury. However, these plasma-based assays alone often lack the sensitivity to diagnose and adequately treat coagulopathy associated with traumatic brain injury. Here, we review the whole blood coagulation assays termed viscoelastic tests and their use in traumatic brain injury. Modified viscoelastic tests with platelet function assays have helped elucidate the underlying pathophysiology and guide clinical decisions in a goal-directed fashion. Platelet dysfunction appears to underlie most coagulopathies in this patient population, particularly at the adenosine diphosphate and/or arachidonic acid receptors. Future research will focus not only on the utility of viscoelastic tests in diagnosing coagulopathy in traumatic brain injury, but also on better defining the use of these tests as evidence-based and/or precision-based tools to improve patient outcomes.

Incidence of venous thromboembolism in hospitalized pediatric neurosurgical patients: a retrospective 25-year institutional experience.

PURPOSE: Venous thromboembolism (VTE) refers to both deep venous thrombosis (DVT) and pulmonary embolism (PE). The risk of VTE in adult neurosurgical patients is thoroughly studied. However, the incidence and risk of VTE in a comprehensive pediatric neurosurgical population is not well-defined. The available pediatric data consists of reviews of specific high-risk groups, such as trauma, critical care, or cancer patients. This may not be reflective of the entire spectrum of a high-volume pediatric neurosurgery practice. This study was undertaken to analyze the incidence and risk factors of VTE in all hospitalizations evaluated by a pediatric neurosurgery service over a 25-year period. METHODS: A retrospective review of electronic medical records was performed for 9149 hospitalizations in 6374 unique patients evaluated by the pediatric neurosurgery service at Riley Hospital for Children (Indianapolis, IN, USA) from 1990-2014. During this time period, there was no standardized VTE prevention protocol. The study group included all patients less than 18 years of age. Patients with a known pre-existing VTE or pregnancy were excluded. RESULTS: VTE was diagnosed in 20 of the 9149 (0.22%) hospitalizations, in 18 unique patients. All DVTs were diagnosed via Doppler ultrasound and/or computed tomography. Anatomic clot locations included 9 in the upper extremity (0.098% of hospitalizations), 8 in the lower extremity (0.087%), and 4 (0.044%) pulmonary emboli. Ten of the 20 occurred in hospitalizations where the patient underwent surgery, although the need for surgery was not a statistically significant risk factor. Sixteen of the 20 (80%) occurred in patients with at least one form of central venous line (p < 0.00001). There was one VTE-related death (0.01%). CONCLUSIONS: In all pediatric neurosurgical patients, a VTE was found in 0.22% of hospitalizations over a 25-year span. Statistically significant risk factors for VTE included central venous line placement, paralysis, malignancy, intubation greater than 48 h, and hypercoagulable state.

Thromboelastography-Guided Therapy of Hemorrhagic Complications after Craniopharyngioma Resection: Case-Based Update.

PURPOSE: Thromboelastography (TEG) is a point-of-care test that evaluates the entire hemostatic process. The use of TEG is expanding in multiple pediatric surgical disciplines. However, there is very little literature regarding its application in pediatric neurosurgical patients. METHODS: The authors provide a case-based update and literature review regarding potential applications of TEG to pediatric neurosurgical patients. RESULTS: The authors describe a 12-year-old female who experienced a number of complications after a craniopharyngioma resection. The patient suffered multiple new intraventricular hemorrhages with removal of external ventricular drains. Standard coagulopathy tests did not reveal any abnormalities. However, an abnormal TEG value suggested primary hyperfibrinolysis, which led to a change in medical management. The patient did not suffer any further bleeding episodes after the change in treatment. CONCLUSIONS: The authors discuss a case where TEG influenced patient management and identified a problem despite normal values of standard laboratory tests. Neurosurgeons should be aware of the potential benefits for TEG testing in pediatric patients.

Complications of Insufficient Dura and Blood Loss During Surgical Intervention in Shprintzen-Goldberg Syndrome: A Case Report.

BACKGROUND Shprintzen-Goldberg syndrome (SGS) is an extremely rare collagenopathy, most often caused by autosomal-dominant mutations in the SKI proto-oncogene, which is a component of the transforming growth factor beta (TGF-ß) signaling pathway. Approximately 50-60 cases of SGS have been recorded in the literature worldwide since its discovery in 1982. This collagen disorder affects bone and vascular development throughout the body, resulting in craniosynostosis, scoliosis, chest deformities, and aortic root dilation. Patients may have problems in the central nervous system, including Chiari 1 malformation, hydrocephalus, and dilation of the lateral ventricles. Unfortunately, the symptoms of SGS closely parallel those of related collagenopathies involving mutations in the TGF-ß signaling pathway, which makes accurate diagnosis difficult without genetic testing, especially in cases with complex presentation. CASE REPORT In this report we present the unique and complex disease manifestations in a 9-year-old girl with SGS. The patient had severe cervical spinal instability that resolved after surgical occipital-C4 fusion with an autograft from the rib. Midface distraction surgery was used to treat the patient's craniosynostosis and related facial deformities. This surgery was complicated by loss of 750 mL of blood due to insufficient dura and prominent vasculature. CONCLUSIONS Connective tissue symptoms associated with SGS can involve dural and vascular problems, as seen in this case report. Thus, the risk of extreme blood loss should be anticipated any time midface distraction surgery is performed on an SGS patient. Continued research is needed to define how this case relates to the SGS patient population.

Rapidly growing, multifocal, benign choroid plexus tumor in an infant: case report.

Choroid plexus papillomas (CPPs) are rare, benign tumors that can arise in young children. Most pediatric patients present with signs of hydrocephalus and require immediate treatment. The natural history of choroid plexus tumors in children without hydrocephalus is poorly defined. In this report, the authors present the very rare case of a child without hydrocephalus but with two intraventricular choroid plexus tumors discovered shortly after birth. Initial imaging had been performed for seizures and showed agenesis of the corpus callosum and enhancing tumors in the third and left lateral ventricles. Sequential imaging demonstrated rapid growth of both tumors. The lateral tumor was removed when the child was 3 months of age. A histological examination of the specimen showed benign features with an elevated mitotic rate. Given the patient's age of under 3 years, the diagnosis was WHO grade I CPP. The third ventricle tumor grew rapidly. A second surgery was performed and this tumor was resected. Again, the pathological diagnosis was WHO grade I CPP. The authors present this rare case and discuss the current relevant literature.

Primary Spinal Intradural Extraosseous Ewing Sarcoma in a Pediatric Patient: Case Report and Review of the Literature.

Ewing sarcoma (ES) is an aggressive, primary bone malignancy with occasional soft tissue extension. Purely extra-osseous ES is rare. A primary intraspinal, intradural ES without bone involvement is exceedingly rare. ES may be differentiated from other primitive neuroectodermal tumors by molecular analysis. The authors report the case of a 14-year-old female who suffered an acute neurologic decline from a hemorrhagic, intraspinal, intradural ES. The patient has been tumor free for 2 years after the initial emergency surgery. Our management of the patient and a review of the literature are provided. Considering only those cases with molecular or genetic confirmation of ES, our patient is the fifth pediatric case reported in the English literature.

Growth and alignment of the pediatric subaxial cervical spine following rigid instrumentation and fusion: a multicenter study of the Pediatric Craniocervical Society.

OBJECTIVE The long-term effects of surgical fusion on the growing subaxial cervical spine are largely unknown. Recent cross-sectional studies have demonstrated that there is continued growth of the cervical spine through the teenage years. The purpose of this multicenter study was to determine the effects of rigid instrumentation and fusion on the growing subaxial cervical spine by investigating vertical growth, cervical alignment, cervical curvature, and adjacent-segment instability over time. METHODS A total of 15 centers participated in this multi-institutional retrospective study. Cases involving children less than 16 years of age who underwent rigid instrumentation and fusion of the subaxial cervical spine (C-2 and T-1 inclusive) with at least 1 year of clinical and radiographic follow-up were investigated. Charts were reviewed for clinical data. Postoperative and most recent radiographs, CT, and MR images were used to measure vertical growth and assess alignment and stability. RESULTS Eighty-one patients were included in the study, with a mean follow-up of 33 months. Ninety-five percent of patients had complete clinical resolution or significant improvement in symptoms. Postoperative cervical kyphosis was seen in only 4 patients (5%), and none developed a swan-neck deformity, unintended adjacent-level fusion, or instability. Of patients with at least 2 years of follow-up, 62% demonstrated growth across the fusion construct. On average, vertical growth was 79% (4-level constructs), 83% (3-level constructs), or 100% (2-level constructs) of expected growth. When comparing the group with continued vertical growth to the one without growth, there were no statistically significant differences in terms of age, sex, underlying etiology, surgical approach, or number of levels fused. CONCLUSIONS Continued vertical growth of the subaxial spine occurs in nearly two-thirds of children after rigid instrumentation and fusion of the subaxial spine. Failure of continued vertical growth is not associated with the patient's age, sex, underlying etiology, number of levels fused, or surgical approach. Further studies are needed to understand this dichotomy and determine the long-term biomechanical effects of surgery on the growing pediatric cervical spine.

Pediatric Pontine Cavernous Malformations: The Presigmoid, Posterior Petrosal Approach.

BACKGROUND: Brainstem cavernous malformations (cavernomas) in children have a high risk of hemorrhage and neurological deterioration. This risk is magnified if the child has a genetic predisposition for cavernoma formation. The surgical management is challenging and carries a significant risk of morbidity. OBJECTIVE: To describe the feasibility of a posterior petrosal approach to brainstem cavernomas in a pediatric population. METHODS: A single institution operative experience with this technique was reviewed; 2 cases were identified and are technically described here with supportive figures and illustrations, as well as a focused literature review. RESULTS: Two pediatric cases with multiple symptomatic hemorrhages from large expanding pontine cavernomas were identified. Both cavernomas were resected through a presigmoid posterior petrosal approach. While this approach is well described in the adult literature for ventral brainstem lesions, its description for the treatment of pontine cavernomas in the pediatric populations is scarce. CONCLUSION: This study demonstrates the utility and feasibility of the posterior petrosal approach in two pediatric patients at different points in cranial base development.

Parent/guardian knowledge regarding implanted shunt type, setting, and symptoms of malfunction/infection.

OBJECTIVE Patients with shunts often interact with providers distant from their primary hospital, making it important that the parent(s)/guardian(s) is well versed in the type of shunt implanted and symptoms of malfunction/infection. This is particularly important with magnetic-sensitive programmable valves, as the use of MRI becomes more prevalent. METHODS Over a 6-month period, primary caregivers of 148 consecutive patients who received shunts were prospectively administered questionnaires at clinic visits. Caregivers were asked to do the following: 1) identify shunt valve name, type, and setting if applicable; 2) list symptoms of shunt malfunction/infection; and 3) indicate whether they had access to references regarding shunt type/setting, booklets from the Hydrocephalus Association, and quick reference cards with symptoms of shunt malfunction/infection. One cohort of caregivers (n = 75) was asked to carry informational cards with shunt valve/setting information (group I); this cohort was compared with another subgroup of caregivers (n = 73) not carrying cards (group II). RESULTS The mean (± SD) age of patients at implantation/revision was 3.71 ± 4.91 years, and the age at follow-up was 6.12 ± 5.4 years. The average time from surgery to administration of the questionnaire was 2.38 ± 3.22 years. There were 86 new shunt insertions and 62 revisions. One hundred twenty-eight caregivers (87%) could identify the type of valve (programmable vs nonprogrammable). On the other hand, only 72 caregivers (49%) could identify the valve name. Fifty-four of 73 (74%) caregivers of patients who had shunts with programmable valves could correctly identify the valve setting. One hundred caregivers (68%) had a copy of the Hydrocephalus Association booklet, and 103 (70%) had quick reference cards. Eighty caregivers (54%) had references on shunt type/setting. Most caregivers (127 [86%]) could name ≥ 3 signs/symptoms of shunt malfunction, with vomiting (61%), headache (49%), and sleeps more/lethargic (35%) most frequently reported. Caregivers of patients in group I were more likely to have cards with symptoms of shunt infection or malfunction (p = 0.015); have information cards regarding shunt type/setting (p < 0.001); and correctly identify valve type (p = 0.001), name (p < 0.001), and setting if programmable (p = 0.0016). There were no differences in ability to list symptoms of shunt malfunction or infection (p = 0.8812) or in access to Hydrocephalus Association booklets (p = 0.1288). There were no significant demographic differences between the groups, except that group I patients had a shorter time from surgery to last follow-up (1.66 vs 3.17 years; p = 0.0001). CONCLUSIONS Education regarding the care of patients with shunts by providing written cards with shunt type/setting and access to reference materials seems to be effective. Developing plans for guided instruction with assessment in the clinic setting of a caregiver's knowledge is important for patient safety.

Failure of ETV in patients with the highest ETV success scores.

OBJECTIVE Endoscopic third ventriculostomy (ETV) is a surgical alternative to placing a CSF shunt in certain patients with hydrocephalus. The ETV Success Score (ETVSS) is a reliable, simple method to estimate the success of the procedure by 6 months of postoperative follow-up. The highest score is 90, estimating a 90% chance of the ETV effectively treating hydrocephalus without requiring a shunt. Treatment with ETV fails in certain patients, despite their being the theoretically best candidates for the procedure. In this study the authors attempted to identify factors that further predicted success in patients with the highest ETVSSs. METHODS A retrospective review was performed of all patients treated with ETV at 3 institutions. Demographic, radiological, and clinical data were recorded. All patients by definition were older than 1 year, had obstructive hydrocephalus, and did not have a prior shunt. Failure of ETV was defined as the need for a shunt by 1 year. The ETV was considered a success if the patient did not require another surgery (either shunt placement or a repeat endoscopic procedure) by 1 year. A statistical analysis was performed to identify factors associated with success or failure. RESULTS Fifty-nine patients met the entry criteria for the study. Eleven patients (18.6%) required further surgery by 1 year. All of these patients received a shunt. The presenting symptom of lethargy statistically correlated with success (p = 0.0126, odds ratio [OR] = 0.072). The preoperative radiological finding of transependymal flow (p = 0.0375, OR 0.158) correlated with success. A postoperative larger maximum width of the third ventricle correlated with failure (p = 0.0265). CONCLUSIONS The preoperative findings of lethargy and transependymal flow statistically correlated with success. This suggests that the best candidates for ETV are those with a relatively acute elevation of intracranial pressure. Cases without these findings may represent the failures in this highly selected group.

Risk of deep venous thrombosis in elective neurosurgical procedures: a prospective, Doppler ultrasound-based study in children 12 years of age or younger.

OBJECTIVE The risk of venous thromboembolism (VTE) from deep venous thrombosis (DVT) is significant in neurosurgical patients. VTE is considered a leading cause of preventable hospital deaths and preventing DVT is a closely monitored quality metric, often tied to accreditation, hospital ratings, and reimbursement. Adult protocols include prophylaxis with anticoagulant medications. Children's hospitals may adopt adult protocols, although the incidence of DVT and the risk or efficacy of treatment is not well defined. The incidence of DVT in children is likely less than in adults, although there is very little prospectively collected information. Most consider the risk of DVT to be extremely low in children 12 years of age or younger. However, this consideration is based on tradition and retrospective reviews of trauma databases. In this study, the authors prospectively evaluated pediatric patients undergoing a variety of elective neurosurgical procedures and performed Doppler ultrasound studies before and after surgery. METHODS A total of 100 patients were prospectively enrolled in this study. All of the patients were between the ages of 1 month and 12 years and were undergoing elective neurosurgical procedures. The 91 patients who completed the protocol received a bilateral lower-extremity Doppler ultrasound examination within 48 hours prior to surgery. Patients did not receive either medical or mechanical DVT prophylaxis during or after surgery. The ultrasound examination was repeated within 72 hours after surgery. An independent, board-certified radiologist evaluated all sonograms. We prospectively collected data, including potential risk factors, details of surgery, and details of the clinical course. All patients were followed clinically for at least 1 year. RESULTS There was no clinical or ultrasound evidence of DVT or VTE in any of the 91 patients. There was no clinical evidence of VTE in the 9 patients who did not complete the protocol. CONCLUSIONS In this prospective study, no DVTs were found in 91 patients evaluated by ultrasound and 9 patients followed clinically. While the study is underpowered to give a definitive incidence, the data suggest that the risk of DVT and VTE is very low in children undergoing elective neurosurgical procedures. Prophylactic protocols designed for adults may not apply to pediatric patients. Clinical trial registration no.: NCT02037607 (clinicaltrials.gov).

Frontal burr hole approach for neuroendoscopic resection of craniopharyngioma with the NICO Myriad device: report of two cases.

OBJECTIVE: Craniopharyngiomas are challenging tumors to resect due to their deep location and proximity to vital structures. The perceived benefit of gross total resection may be tempered by the possibility of permanent disability. Minimally invasive techniques may reduce surgical morbidity while still allowing effective resection. The authors describe their initial experience with a neuroendoscopic transcortical, transventricular approach to two craniopharyngiomas. The surgeries were performed through a right frontal burr hole using the NICO Myriad, a side-cutting, aspiration device that fits through the working channel of a standard neuroendoscope. METHODS: The imaging and medical records of two children (a 5-year-old male and a 9-year-old female) undergoing endoscopic resection of a craniopharyngioma with this technique were reviewed. Outcomes, results, and complications were noted. RESULTS: A gross total resection was achieved in both patients. The operative time was 180 and 143 min, respectively. The estimated blood loss was 20 and 50 cm3, respectively. Both patients required a cerebrospinal fluid shunt. There were no surgical complications. CONCLUSIONS: The NICO Myriad is an effective tool that allows a safe minimally invasive endoscopic resection of craniopharyngiomas in patients with amenable anatomy. Surgeons with experience in neuroendoscopy may be able to achieve a gross total resection of these challenging tumors through a minimally invasive burr hole approach.

Multicenter retrospective evaluation of the validity of the Thoracolumbar Injury Classification and Severity Score system in children.

OBJECTIVE The Thoracolumbar Injury Classification and Severity Score (TLICS) system was developed to streamline injury assessment and guide surgical decision making. To the best of the authors' knowledge, external validation in the pediatric age group has not been undertaken prior to this report. METHODS This study evaluated the use of the TLICS in a large retrospective series of children and adolescents treated at 4 pediatric medical centers (Texas Children's Hospital, Children's Healthcare of Atlanta, Riley Children's Hospital, and Doernbecher Children's Hospital). A total of 147 patients treated for traumatic thoracic or lumbar spine trauma between February 1, 2002, and September 1, 2015, were included in this study. Clinical and radiographic data were evaluated. Injuries were classified using American Spinal Injury Association (ASIA) status, Denis classification, and TLICS. RESULTS A total of 102 patients (69%) were treated conservatively, and 45 patients (31%) were treated surgically. All patients but one in the conservative group were classified as ASIA E. In this group, 86/102 patients (84%) had Denis type compression injuries. The TLICS in the conservative group ranged from 1 to 10 (mean 1.6). Overall, 93% of patients matched TLICS conservative treatment recommendations (score ≤ 3). No patients crossed over to the surgical group in delayed fashion. In the surgical group, 26/45 (58%) were ASIA E, whereas 19/45 (42%) had neurological deficits (ASIA A, B, C, or D). One of 45 (2%) patients was classified with Denis type compression injuries; 25/45 (56%) were classified with Denis type burst injuries; 14/45 (31%) were classified with Denis type seat belt injuries; and 5/45 (11%) were classified with Denis type fracture-dislocation injuries. The TLICS ranged from 2 to 10 (mean 6.4). Eighty-two percent of patients matched TLICS surgical treatment recommendations (score ≥ 5). No patients crossed over to the conservative management group. Eight patients (8/147, 5%) had a calculated TLICS of 4, which meant they were candidates for surgery or conservative therapy by TLICS criteria. Excluding these patients, the degree of agreement between TLICS and surgeon decision was deemed to be very good (κ = 0.878). CONCLUSIONS The TLICS results and recommendations matched treatment in 96% of conservative group cases. In the surgical group, TLICS recommendations matched treatment in 93% of cases. The TLICS recommendations and surgeon decision making displayed very good concordance. The TLICS appears to be effective in the classification of thoracic and lumbar spine injuries and in guiding treatment in the pediatric age group.

Efficacy of phosphorus-32 brachytherapy without external-beam radiation for long-term tumor control in patients with craniopharyngioma.

OBJECT Radioactive phosphorus-32 (P32) has been used as brachytherapy for craniopharyngiomas with the hope of providing local control of enlarging tumor cysts. Brachytherapy has commonly been used as an adjunct to the standard treatment of surgery and external-beam radiation (EBR). Historically, multimodal treatment, including EBR, has shown tumor control rates as high as 70% at 10 years after treatment. However, EBR is associated with significant long-term risks, including visual deficits, endocrine dysfunction, and cognitive decline. Theoretically, brachytherapy may provide focused local radiation that controls or shrinks a symptomatic cyst without exposing the patient to the risks of EBR. For this study, the authors reviewed their experiences with craniopharyngioma patients treated with P32 brachytherapy as the primary treatment without EBR. The authors reviewed these patients' records to evaluate whether this strategy effectively controls tumor growth, thus avoiding the need for further surgery or EBR. METHODS The authors performed a retrospective review of pediatric patients treated for craniopharyngioma between 1997 and 2004. This was the time period during which the authors' institution had a relatively high use of P32 for treatment of cystic craniopharyngioma. All patients who had surgery and injection of P32 without EBR were identified. The patient records were analyzed for complications, cyst control, need for further surgery, and need for future EBR. RESULTS Thirty-eight patients were treated for craniopharyngioma during the study period. Nine patients (23.7%) were identified who had surgery (resection or biopsy) with P32 brachytherapy but without initial EBR. These 9 patients represented the study group. For 1 patient (11.1%), there was a complication with the brachytherapy procedure. Five patients (55.5%) required subsequent surgery. Seven patients (77.7%) required subsequent EBR for tumor growth. The mean time between the injection of P32 and subsequent treatment was 1.67 ± 1.50 years (mean ± SD). CONCLUSIONS In this small but focused population, P32 treatment provided limited local control for cyst growth. Brachytherapy alone did not reliably avert the need for subsequent surgery or EBR.

Rapidly enlarging low-grade fibromyxoid sarcoma with intracranial extension in a 5-year-old girl: case report.

Low-grade fibromyxoid sarcoma (LGFMS) is a rare mesenchymal tumor that is characterized by a benign histology but potentially aggressive clinical behavior, with a high rate of recurrence and metastasis. It primarily occurs in young adults in the extremities, inguinal area, neck, or chest wall. There are rare reports of intracranial LGFMS in adults. In this report, the authors present the case of a 5-year-old girl who presented with a rapidly enlarging frontal scalp mass. Pathological examination of the resected mass demonstrated LGFMS. To the authors' knowledge, this is the only reported case of intracranial LGFMS in a child.

Feasibility of CT-based intraoperative 3D stereotactic image-guided navigation in the upper cervical spine of children 10 years of age or younger: initial experience.

OBJECT Rigid screw fixation may be technically difficult in the upper cervical spine of young children. Intraoperative stereotactic navigation may potentially assist a surgeon in precise placement of screws in anatomically challenging locations. Navigation may also assist in defining abnormal anatomy. The object of this study was to evaluate the authors' initial experience with the feasibility and accuracy of this technique, both for resection and for screw placement in the upper cervical spine in younger children. METHODS Eight consecutive pediatric patients 10 years of age or younger underwent upper cervical spine surgery aided by image-guided navigation. The demographic, surgical, and clinical data were recorded. Screw position was evaluated with either an intraoperative or immediately postoperative CT scan. RESULTS One patient underwent navigation purely for guidance of bony resection. A total of 14 navigated screws were placed in the other 7 patients, including 5 C-2 pedicle screws. All 14 screws were properly positioned, defined as the screw completely contained within the cortical bone in the expected trajectory. There were no immediate complications associated with navigation. CONCLUSIONS Image-guided navigation is feasible within the pediatric cervical spine and may be a useful surgical tool for placing screws in a patient with small, often difficult bony anatomy. The authors describe their experience with their first 8 pediatric patients who underwent navigation in cervical spine surgery. The authors highlight differences in technique compared with similar navigation in adults.

Dorsal midline hemivertebra at the lumbosacral junction: report of 2 cases.

Congenital scoliosis from laterally located hemivertebrae at the lumbosacral junction has been described previously. However, dorsally located midline hemivertebrae at this location have not been reported. The authors describe the presentation, treatment, and outcomes of 2 patients (1 male and 1 female) with this rare malformation. All clinical and radiographic records were reviewed. Outcomes were recorded using survey instruments (Oswestry Disability Index and the 36-Item Short Form Health Survey). Radiographic assessment of bony fusion was performed using CT scanning 1 year after surgery. Both patients presented with back and leg pain, urinary hesitancy/incontinence, difficulty sitting and lying down, waddling gait, and restriction of movement. Imaging showed a wedge-shaped dorsal deformity that stretched the nerve roots and compressed the canal. Both patients underwent resection of the hemivertebra with posterolateral instrumented fusion from L-2 to the pelvis. The female patient had a low-lying conus and underwent sectioning of the filum terminale. Both patients showed improvement in the ability to sit and lie flat and in bowel and bladder function after surgery. The authors describe their experience with 2 patients with similar, rare congenital bony deformities at the lumbosacral junction. To their knowledge, similar cases have not been previously reported.

Rathke's cleft cysts in twins with type 2C von Hippel-Lindau disease.

Von Hippel-Lindau disease (VHLD) is characterized by a spectrum of benign and malignant tumors in the CNS and visceral organs. Rathke's cleft cysts are benign, nonneoplastic sellar lesions that are often asymptomatic. The authors report the case of twin sisters with VHLD Type 2C with radiographically similar sellar lesions. One twin required surgery for progressive visual loss. Pathological examination of resected tissue demonstrated Rathke's cleft cyst.

Fixation with C-2 laminar screws in occipitocervical or C1-2 constructs in children 5 years of age or younger: a series of 18 patients.

UNLABELLED: OBJECT.: There are rare indications for upper cervical spine fusion in young children. Compared with nonrigid constructs, rigid instrumentation with screw fixation increases the fusion rate and reduces the need for halo fixation. Instrumentation may be technically challenging in younger children. A number of screw placement techniques have been described. Use of C-2 translaminar screws has been shown to be anatomically feasible, even in the youngest of children. However, there are few data detailing the clinical outcome. In this study, the authors describe the clinical and radiographic follow-up of 18 children 5 years of age or younger who had at least one C-2 translaminar screw as part of an occipitocervical or C1-2 fusion construct. METHODS: A retrospective review of all children treated with instrumented occipitocervical or C1-2 fusion between July 1, 2007, and June 30, 2013, at Riley Children's Hospital and Texas Children's Hospital was performed. All children 5 years of age or younger with incorporation of at least one C-2 translaminar screw were identified. RESULTS: Eighteen children were studied (7 boys and 11 girls). The mean age at surgery was 38.1 months (range 10-68 months). Indications for surgery included traumatic instability (6), os odontoideum (3), destructive processes (2), and congenital instability (7). A total of 24 C-2 translaminar screws were placed; 23 (95.8%) of 24 were satisfactorily placed (completely contained within the cortical walls). There was one medial cortex breach without neurological impingement. There were no complications with screw placement. Three patients required wound revisions. Two patients died as a result of their original condition (trauma, malignant tumor). The mean follow-up duration for the surviving patients was 17.5 months (range 3-60 months). Eleven (91.7%) of the 12 patients followed for 6 months or longer showed radiographic stability or completed fusion. CONCLUSIONS: Use of C-2 translaminar screws provides an effective anchor for internal fixation of the upper cervical spine. In this study of children 5 years of age or younger, the authors found a high rate of radiographic fusion with a low rate of complications.