Open reduction and internal fixation for angulated, unstable odontoid synchondrosis fractures in children: a safe alternative to halo fixation?

External orthosis is the accepted and historical management of odontoid synchondrosis fractures; however, this conservative therapy carries a significant complication and fracture nonunion rate among young children. The purpose of this study was to evaluate the authors' own experience in the context of the literature, to explore surgical fixation as a primary treatment for unstable fractures. The authors retrospectively reviewed 2 cases of unstable odontoid synchondrosis fractures treated at their institution; both showed radiographic progression of deformity and subsequently underwent an open surgical reduction and fusion. A literature review was conducted to compare the authors' management strategy with those in published data. External orthosis for treatment of odontoid synchondrosis fractures has a strong history of success. However, in the literature, patients treated with a halo orthosis had a 43.3% rate of complications and an 11.4% risk of nonunion. There are radiographic findings that suggest instability, such as severe angulation and displacement of the odontoid process. Both patients in the present report underwent successful fusion without complication, as documented on CT scans obtained 3 months after surgery. Given the high rate of fusion attained with conservative therapy, it is recommended for most synchondrosis fractures. However, there is a recognized subgroup of synchondrosis fractures with severe angulation (> 30°) and displacement suggestive of significant ligamentous injury. In these patients, surgical fixation may be a safe and efficacious alternative to halo orthosis as the primary treatment.

Pulmonary embolus from acute superior sagittal sinus thrombosis secondary to skull fracture: case report

BACKGROUND AND IMPORTANCE

Pulmonary embolus (PE) occurring concurrent with-and as a result of-traumatic superior sagittal sinus thrombosis (SSST) has never before been reported. We report the first case of a patient who presented with acute traumatic SSST and concomitant PE.

CLINICAL PRESENTATION

A 30-year-old man presented with altered mental status after a motorcycle collision, and subsequently developed respiratory distress. Computed tomography (CT) scanning of the head revealed multiple calvarial and skull base fractures, contusions, and hemorrhages. Air was noted within the superior sagittal sinus, indicating a fracture involving the sinus and suggesting thrombus formation. A chest CT scan obtained at the time of presentation revealed a PE in the right pulmonary artery. The patient had no personal or family history of hypercoagulability, and all coagulation study results were within normal limits. Work-up revealed no evidence of long bone fractures or deep venous thrombosis. Initial intervention involved placement of an external ventricular drain, brain tissue oxygen saturation probe, internal jugular venous oxygen saturation monitor, arterial line, and central venous line with extensive treatment of all abnormal values according to established standards. Ultimately, pentobarbital coma was initiated for persistently elevated intracranial pressure (ICP) refractory to conservative measures. Aggressive pulmonary resuscitation was required to maintain adequate oxygenation. Anticoagulation was begun 3 weeks after admission.

CONCLUSION

Our patient had good neurological recovery. This report highlights the possibility of acute PE in the setting of traumatic SSST.

Epidemiology of metastatic brain tumors

Metastatic tumors are the most common brain tumors in adults, and their incidence is increasing. An accurate understanding of the epidemiology of metastatic brain tumors is useful for health care professionals to allocate appropriate clinical, diagnostic, therapeutic, and research resources. Reported incidences in the literature are derived from epidemiologic population-based studies; clinical studies from surgical, radiological, and autopsy series; and reviews of hospital and clinical medical records. Despite these various sources of information, an accurate incidence of metastatic brain tumors is difficult, and current figures are estimates at best. Here, we review the available data regarding the epidemiology of metastatic brain tumors.

A clinicopathologic correlation in osteoblastoma of the spine in a child

Spinal osteoblastomas are considered benign tumors but can be locally aggressive. Patients usually present with pain and undergo radiologic and histologic work-up to establish a diagnosis. Osteoblastomas have discordant appearances on CT scans and MRI because of the inflammatory response seen on MRI that characterizes these tumors - the "flare" phenomenon. Solely using MRI can lead to over-resection, as signal abnormality may include areas devoid of tumor. There are a few reports of this phenomenon in the radiology literature, but to our knowledge, there are none in neurosurgery journals. We report an 11-year-old boy who presented with back pain and radiculopathy with an osteoblastoma at the L4 level. We totally excised the lesion to definitively treat the patient but also, based on MRI findings, differentially biopsied portions of the lesion and correlated them to the imaging studies, to confirm that the intense reactive portion of the lesion was devoid of tumor cells.

Publication patterns of oral and poster presentations at the annual meetings of the Congress of Neurological Surgeons and the American Association of Neurological Surgeons

OBJECT

National and international meetings, such as the Congress of Neurological Surgeons (CNS) and the American Association of Neurological Surgeons (AANS) meetings, provide a central location for the gathering and dissemination of research. The purpose of this study was to determine the publication rates of both oral and poster presentations at CNS and AANS meetings in peer-reviewed journals.

METHODS

The authors reviewed all accepted abstracts, presented as either oral or poster presentations, at the CNS and AANS meetings from 2003 to 2005. This information was then used to search PubMed to determine the rate of publication of the abstracts presented at the meetings. Abstracts were considered published if the data presented at the meeting was identical to that in the publication.

RESULTS

The overall publication rate was 32.48% (1243 of 3827 abstracts). On average, 41.28% of oral presentations and 29.03% of poster presentations were eventually published. Of those studies eventually published, 98.71% were published within 5 years of presentation at the meeting. Published abstracts were published most frequently in the Journal of Neurosurgery and Neurosurgery.

CONCLUSIONS

Approximately one-third of all presentations at the annual CNS and AANS meetings will be published in peer-reviewed, MEDLINE-indexed journals. These meetings are excellent forums for neurosurgical practitioners to be exposed to current research. Oral presentations have a significantly higher rate of eventual publication compared with poster presentations, reflecting their higher quality. The Journal of Neurosurgery and Neurosurgery have been the main outlets of neurosurgical research from these meetings.

The unwritten price of cosmetic tourism: an observational study and cost analysis

INTRODUCTION AND AIMS

Cosmetic tourism, driven by the promise of inexpensive operations abroad, is increasingly popular despite warnings from professional bodies regarding associated risks. Increasing numbers of individuals have presented to our department requesting NHS treatment of complications from such surgery. We set out to characterize these patients and evaluate costs incurred through their assessment and management.

MATERIAL AND METHODS

An observational study was conducted from 2007 to 2009 on patients presenting to a tertiary referral Plastic Surgery practice with complications of cosmetic tourism surgery. Demographic characteristics, as well as those related to the operation, were recorded. Hospital patient flow pathways were constructed, cost analysis performed using Patient Level Costing, and expenditure and profitability calculated.

KEY RESULTS

Nineteen patients presented within the study period. Most operations were performed in Europe or Asia, and were primarily breast augmentation procedures (n=13). The principal complications were wound infection or dehiscence, and poor cosmetic results. Eleven patients received NHS treatment, at a cost of £120,841. The mean cost for all patients' management was £6360 (range: £114-£57,968), rising to £10,878 for those accepted for treatment. For 8 of the 9 patients (89%) for whom full patient level costing was available, the hospital incurred a financial loss.

CONCLUSION

The costs to the NHS of managing complications of cosmetic tourism are substantial, and underestimated by central funding agencies.

Rare association between cystic fibrosis, Chiari I malformation, and hydrocephalus in a baby: a case report and review of the literature

Introduction

Cystic fibrosis, an epithelial cell transport disorder caused by mutations of the cystic fibrosis transmembrane conductance regulator gene, is not generally associated with malformations of the central nervous system. We review eight previously published reports detailing an infrequent association between cystic fibrosis and Chiari I malformation.

Case presentation

To the best of our knowledge, our report describes only the ninth case of a baby presenting with a new diagnosis of cystic fibrosis and Chiari I malformation, in this case in a 10-month-old, full-term Caucasian baby boy from the United States of America. Neurosurgical consultation was obtained for associated developmental delay, macrocephaly, bulging anterior fontanel, and papilledema. An MRI scan demonstrated an extensive Chiari I malformation with effacement of the fourth ventricle, obliteration of the outlets of the fourth ventricle and triventricular hydrocephalus without aqueductal stenosis. Our patient was taken to the operating room for ventriculoperitoneal shunt placement.

Conclusions

It is possible that the cystic fibrosis transmembrane conductance regulator gene may play a previously unrecognized role in central nervous system development; alternatively, this central nervous system abnormality may have been acquired due to constant valsalva from recurrent coughing or wheezing or metabolic and electrolyte imbalances that occur characteristically in cystic fibrosis.

Preventing cerebrospinal fluid leak following transection of a tight filum terminale

OBJECT

Tethered cord release for a tight filum terminale is a common pediatric operation associated with low morbidity and mortality rates. While almost all would agree that keeping patients lying flat after the operation will prevent a CSF leak, the optimal period of doing so has not been determined. In this study, the authors examined whether a longer length of stay in the hospital for the sole purpose of maintaining patients flat correlates with a decreased rate of CSF leakage.

METHODS

Intraoperative and postoperative data were retrospectively collected in 222 cases of simple tethered cord release at 3 large children's hospitals. Risk factors for postoperative CSF leakage were identified.

RESULTS

Thirty-eight patients were maintained lying flat for 24 hours, 86 for 48 hours, and 98 for 72 hours at the individual surgeon's discretion. A CSF leak occurred in 13 patients (5.9%) and pseudomeningocele developed in 9 patients (4.1%). In the univariate analysis, operating time, use of the microscope, use of dural sealant, and duration of remaining flat after surgery failed to correlate with the occurrence of complications.

CONCLUSIONS

A longer hospital stay for maintaining patients flat after a simple tethered cord release appears not to prevent CSF leakage. However, a larger patient cohort will be needed to detect small differences in complication rates.

Computed tomography morphometric analysis for translaminar screw fixation in the upper thoracic spine of the pediatric population

OBJECT

Translaminar screw (TLS) fixation can be used safely and efficaciously for upper cervical fusion in children. No published studies have evaluated this technique in the thoracic spine of the pediatric population, and thus the authors undertook such an analysis.

METHODS

The upper thoracic spines (T1-4) of 130 patients, consisting of 70 boys and 60 girls, were studied using CT scans. Laminar height and thickness, screw length, and screw angle were measured. Exclusion criteria included the following: patients older than 18 years of age, trauma or congenital abnormalities of the thoracic spine, or absent demographic information or imaging studies through T-4. Statistical analysis was performed using paired or unpaired Student t-tests (p < 0.05) and linear regression analysis.

RESULTS

The mean laminar heights for T-1, T-2, T-3, and T-4 were as follows: 12.3 ± 3.4, 13.0 ± 3.5, 13.4 ± 3.8, and 14.7 ± 4.1 mm, respectively. The mean laminar widths were 6.5 ± 1.3, 6.6 ± 1.3, 6.6 ± 1.3, and 6.6 ± 1.4 mm, respectively. The mean screw lengths were 29.9 ± 4.1, 25.2 ± 3.5, 22.7 ± 3.2, and 21.6 ± 3.1 mm, respectively. The mean screw angles were 47° ± 4°, 48° ± 4°, 51° ± 4°, and 53° ± 5°, respectively. There were no significant differences between the right and left sides. However, significant differences were found when comparing patients younger than 8 years with those who were 8 years or older, and when comparing boys and girls.

CONCLUSIONS

Careful preoperative thin-cut CT with sagittal reconstruction is mandatory to determine if the placement of TLSs is feasible in the pediatric population. Based on CT analysis, the insertion of TLSs in the pediatric thoracic spine is possible in all patients older than 8 years and in many patients younger than 8 years. Boys could accept longer screws in the upper thoracic spine compared with girls.

Analysis of the risk of shunt failure or infection related to cerebrospinal fluid cell count, protein level, and glucose levels in low-birth-weight premature infants with posthemorrhagic hydrocephalus

OBJECT

Premature, low-birth-weight infants with posthemorrhagic hydrocephalus have a high risk of shunt obstruction and infection. Established risk factors for shunt failure include grade of the hemorrhage and age at shunt insertion. There is anecdotal evidence that the amount of red blood cells or protein levels in the CSF may affect shunt performance. However, this has not been analyzed specifically for this cohort of high-risk patients. Therefore, the authors performed this study to examine whether any statistical relationship exists between the CSF constituents and the rate of shunt malfunction or infection in this population.

METHODS

A retrospective cohort study was performed on premature infants born at Riley Hospital for Children from 2000 to 2009. Inclusion criteria were a CSF sample analyzed within 2 weeks prior to shunt insertion, low birth weight (< 1500 grams), prematurity (birth prior to 37 weeks estimated gestational age), and shunt insertion for posthemorrhagic hydrocephalus. Data points included the gestational age at birth and shunt insertion, weight at birth and shunt insertion, history of CNS infection prior to shunt insertion, shunt failure, shunt infection, and the levels of red blood cells, white blood cells, protein, and glucose in the CSF. Statistical analysis was performed to determine any association between shunt outcome and the CSF parameters.

RESULTS

Fifty-eight patients met the study entry criteria. Ten patients (17.2%) had primary shunt failure within 3 months of insertion. Nine patients (15.5%) had shunt infection within 3 months. A previous CNS infection prior to shunt insertion was a statistical risk factor for shunt failure (p = 0.0290) but not for shunt infection. There was no statistical relationship between shunt malfunction or infection and the CSF levels of red blood cells, white blood cells, protein, or glucose before shunt insertion.

CONCLUSIONS

Low-birth-weight premature infants with posthemorrhagic hydrocephalus have a high rate of shunt failure and infection. The authors did not find any association of shunt failure or infection with CSF cell count, protein level, or glucose level. Therefore, it may not be useful to base the timing of shunt insertion on CSF parameters.

Surgical outcome for focal cortical dysplasia: an analysis of recent surgical series

OBJECT

Focal cortical dysplasia (FCD) is an important cause of intractable epilepsy and is at times treatable by resection. The now widespread use of MR imaging and recent advancement of functional imaging have increased the number of patients undergoing surgical treatment for FCD. The objective of this review is to critically examine and to provide a summary of surgical series on FCD published since 2000.

METHODS

Studies concerning surgery for FCD were identified from MEDLINE and references of selected articles and book chapters. Data from these included studies were summarized and analyzed to identify factors correlated with seizure outcome.

RESULTS

Sixteen studies were identified, and 469 patients met our selection criteria. Seizure-free outcome at 1-year postoperatively was achieved in 59.7% of the patients. Children and adults were equally likely to benefit from the surgery. Complete resection (OR 13.7, 95% CI 6.68-28.1; p < 0.0001) and temporal location (OR 2.15, 95% CI 1.26-3.69; p = 0.0073) were two positive prognostic indicators of seizure-free outcome. Utilization of invasive monitoring did not affect the chance of seizure remission, but firm conclusions could not be drawn because patients were not randomized.

CONCLUSIONS

The advancement of modern imaging has transformed the process of surgical candidate selection for partial epilepsy due to FCD. Patients from recent surgical series were more homogeneous in their clinical presentations and might represent FCD as an independent pathological entity. This likely explained the improved surgical outcome for this group of patients. These reports also documented the increased utilization of functional imaging, but their efficacy needs to be verified with further studies.

Posterior reversible encephalopathy syndrome during posterior fossa tumor resection in a child

Posterior reversible encephalopathy syndrome (PRES) has been described in the setting of malignant hypertension, renal disease, eclampsia, and immunosuppression. In addition, a single case of intraoperative (posterior fossa craniotomy) PRES has been reported; however, this case occurred in an adult. The authors present a clinically and radiographically documented case of intraoperative PRES complicating the resection of a posterior fossa tumor in a 6-year-old child. During tumor resection, untoward force was used to circumferentially dissect the tumor, and excessive manipulation of the brainstem led to severe hypertension for a 10-minute period. An immediate postoperative MR image was obtained to rule out residual tumor, but instead the image showed findings consistent with PRES. Moreover, the patient's postoperative clinical findings were consistent with PRES. Aggressive postoperative management of blood pressure and the institution of anticonvulsant therapy were undertaken. The patient made a good recovery; however, he required a temporary tracheostomy and tube feedings for prolonged lower cranial nerve dysfunction. Posterior reversible encephalopathy syndrome can occur as a result of severe hypertension during surgery, even among young children. With prompt treatment, the patient in the featured case experienced significant clinical and radiographic recovery.

Multiple myeloma presenting as solitary mass in the posterior fossa

Intracranial plasma cell tumors are extremely rare and can either be solitary lesions or part of systemic multiple myeloma. We report a 42-year-old woman who presented with a posterior fossa mass and successfully underwent surgical resection, leading to the diagnosis of multiple myeloma. To our knowledge, this is the first reported case of multiple myeloma presenting as a posterior fossa mass lesion. This report highlights the importance of maintaining plasma cell tumor in the differential of intracranial mass with bony involvement. Furthermore, once the diagnosis is established, further work up is critical to evaluate for systemic disease.

Factors influencing the risk of local recurrence after resection of a single brain metastasis

OBJECT

Local recurrence (LR) of a resected brain metastasis occurs in up to 46% of patients. Postoperative whole-brain radiation therapy (WBRT) reduces that incidence. To isolate factors associated with the risk of LR after resection, the authors only studied patients who did not receive adjuvant radiotherapy.

METHODS

The authors reviewed data from 570 cases involving patients who had undergone resection of a previously untreated single brain metastasis at The University of Texas M. D. Anderson Cancer Center between 1993 and 2006 without receiving postoperative WBRT. All tumors were measured preoperatively on MR images. The resection method (en bloc resection [EBR] or piecemeal resection [PMR]) was noted at the time of surgery. Predictors of LR were assessed using the Cox proportional hazards model.

RESULTS

The median patient age was 58 years, 55% were male, and 88% had a Karnofsky Performance Scale Score > or = 80. The most common primary cancers were those of the lung (28%), skin (melanoma, 21%), kidney (19%), and breast (11%). Piecemeal resection was performed in 201 patients (35%) and EBR in 369 (65%). Local recurrence developed in 84 patients (15%). The histological type of the primary cancer did not significantly predict LR; however, 7 of 22 patients with sarcoma developed LR (p = 0.16). The authors identified 2 variables that increased the risk of LR. Undergoing PMR carried a significantly higher LR risk than EBR (crude hazard ratio [HR] 1.7, 95% CI 1.1-2.6, p = 0.03). Tumors exceeding the median volume (9.7 cm(3)) had a significantly higher LR risk than those that were < 9.7 cm(3) (crude HR 1.7; 95% CI 1.1-2.6; p = 0.02). In the multivariate analysis, small tumors removed by EBR had a significantly lower LR risk.

CONCLUSIONS

The LR risk of a single brain metastasis is influenced by biological factors (such as tumor volume) and treatments (such as the resection method). Early administration of postoperative WBRT may be particularly warranted when such negative tumor-related prognostic factors are noted or when treatment-related ones such as PMR are unavoidable.

Vacuum-assisted en bloc resection of large convexity meningiomas. Technical note

Convexity meningiomas are common tumors encountered by neurosurgeons. Retracting, grasping, and mobilizing large convexity meningiomas can be difficult and awkward as well as place unwanted forces on surrounding neurovascular structures. The authors present a safe alternative to traditional retraction and manipulation methods by using a modified bulb syringe connected to standard surgical suction to function as a vacuum retractor. This technique allows for rapid, safe, en bloc resection of large convexity meningiomas with little to no pressure on the surrounding brain. The authors present an illustrative case and describe and discuss the technique.

Neurosurgical rotations or clerkships in US medical schools

OBJECT

Medical student exposure to neurosurgery is limited. To improve the educational interactions between neurosurgeons and medical students as well as neurosurgical medical student rotations or clerkships (NSCs) we must first understand the current status.

METHODS

Two questionnaires were sent, one to every neurosurgery course coordinator or director at each US neurosurgery residency program (99 questionnaires) and one to the associated parent medical school dean's office (91 questionnaires), to assess the current status of NSCs and the involvement of neurosurgeons at their respective institutions.

RESULTS

We received responses from 86 (87%) of 99 neurosurgery course coordinators or directors and 64 (70%) of 91 medical school deans' offices. Most NSCs do not have didactic lectures (53 [62%] of 86 NSCs), provide their medical students with a syllabus or educational handouts (53 [62%] of 86), or have a recommended/required textbook (77 [90%] of 86). The most common method of evaluating students in NSCs is a subjective performance evaluation. Of 64 medical school deans, 38 (59%) felt that neurosurgery should not be a required rotation. Neurosurgical rotations or clerkships are primarily offered to students in their 4th year of medical school, which may be too late for appropriate timing of residency applications. Only 21 (33%) of 64 NSCs offer neurosurgery rotations to 3rd-year students.

CONCLUSIONS

There is significant room for improvement in the neurosurgeon-to-medical student interactions in both the NSCs and during the didactic years of medical school.

Comparative risk of leptomeningeal dissemination of cancer after surgery or stereotactic radiosurgery for a single supratentorial solid tumor metastasis

OBJECTIVE

To test the hypothesis that differential risks of developing leptomeningeal disease (LMD) exist in patients having a single supratentorial brain metastasis resected via a piecemeal or en bloc approach or treated with stereotactic radiosurgery (SRS).

METHODS

Between 1993 and 2006, 827 patients with a supratentorial brain metastasis underwent resection or SRS at The University of Texas M.D. Anderson Cancer Center. The primary outcome was the incidence of LMD.

RESULTS

Resection was performed piecemeal in 191 patients and en bloc in 351 patients; 285 patients received SRS. LMD occurred in 33 patients, 29 in the resection group and 4 in the SRS group. Risk of LMD was significantly higher with piecemeal tumor resection than with other procedures (SRS: hazard ratio [HR] for piecemeal, 5.8; 95% confidence interval [CI], 1.9-17.2; P = 0.002; en bloc, HR for piecemeal, 2.7; 95% CI, 1.3-5.6; P = 0.009). The difference between piecemeal and en bloc was particularly pronounced in patients with a melanoma primary (HR, 8.4; 95% CI, 1.8-39.2; P = 0.007). The risk of LMD was not significantly different between en bloc resection and SRS (HR for en bloc, 2.1; 95% CI, 0.7-6.4; P = 0.21). Similar results were obtained when comparing effects of SRS and both resection approaches after limiting the sample to patients with tumors in a specific volume range.

CONCLUSION

Piecemeal resection of a supratentorial brain metastasis carries a higher risk of LMD than en bloc resection or SRS. Further assessment of the role of the 2 surgical resection approaches and SRS in a controlled prospective setting with large numbers of patients is warranted.

Comparative risk of leptomeningeal disease after resection or stereotactic radiosurgery for solid tumor metastasis to the posterior fossa

Object

The authors tested the hypothesis that patients with metastatic posterior fossa lesions (MPFLs) treated with resection have a higher risk of leptomeningeal disease (LMD) than those with MPFLs treated with stereotactic radiosurgery (SRS).

Methods

Between 1993 and 2004, 379 patients with MPFLs were treated with resection or SRS at The University of Texas M. D. Anderson Cancer Center. The authors' primary study outcome was the incidence of LMD, as diagnosed with cerebrospinal fluid cytological analysis and/or neuroimaging.

Results

Resection was performed in 260 patients, whereas 119 patients underwent SRS. The median patient age was 56 years, 51% of patients were male, and 93% had a Karnofsky Performance Scale score $ 70. The most common primary cancers were those of the lung, breast, and kidney, as well as melanoma. Leptomeningeal dissemination of cancer occurred in 33 patients: 26 in the resection group and 7 in the SRS group (resection group: rate ratio [RR] 2.06, 95% confidence interval [CI] 0.89–4.75, p = 0.09). Piecemeal tumor resection (137 cases) was associated with a significantly higher risk of LMD than en bloc resection (123 cases; RR 3.4, 95% CI 1.43–8.12, p = 0.006) or SRS (RR 3.37, 95% CI 1.41–8.04, p = 0.006), and there was no significant difference in the risk for LMD between en bloc resection and SRS (en bloc resection: RR 0.98, 95% CI 0.34–2.81, p = 0.98). The multivariate RR and significance associated with piecemeal resection, however, were consistent, with a strong effect (RR 2.45, 95% CI 1.19–5.02, p = 0.02) and no indication of biases associated with tumor size, location, or cystic/necrotic appearance.

Conclusions

There is an increased risk of LMD after piecemeal resection of an MPFL. This increase, although clinically and statistically significant, is not as alarming as previously reported and is absent when en bloc removal is achieved. Further assessment of the role of resection in a controlled prospective setting is warranted.

Evaluation and management of patients with propionic acidemia undergoing liver transplantation: a comprehensive review

Propionic acidemia is a rare metabolic disorder that often results in episodic hyperammonemia, basal ganglia infarction, mental retardation, and cardiomyopathy. OLT has been used as a treatment for propionic acidemia, but its benefit in patients with this disease is unclear. The current study was undertaken to clarify the role of OLT in the management of this disease. The medical literature, a national registry of US OLT recipients, and a single institution liver transplant experience were reviewed for cases of OLT for propionic acidemia. Accumulated cases demonstrate that OLT has resulted in clear evidence of clinical improvement in several patients, often obviating the need for dietary restriction or other forms of medical management. OLT appears to halt the decline in neurocognitive function often associated with propionic acidemia. In total, 12 patients with propionic acidemia have undergone a total of 14 OLTs. A quantitative analysis of outcomes shows an overall patient survival rate of 72.2% at one year after OLT. In conclusion, OLT should be considered a treatment option for patients with propionic acidemia who continue to experience episodes of hyperammonemia in spite of maximal medical therapy. Early OLT may limit the development of mental retardation and/or cardiomyopathy.

A protein-protein interaction network for human inherited ataxias and disorders of Purkinje cell degeneration

Many human inherited neurodegenerative disorders are characterized by loss of balance due to cerebellar Purkinje cell (PC) degeneration. Although the disease-causing mutations have been identified for a number of these disorders, the normal functions of the proteins involved remain, in many cases, unknown. To gain insight into the function of proteins involved in PC degeneration, we developed an interaction network for 54 proteins involved in 23 inherited ataxias and expanded the network by incorporating literature-curated and evolutionarily conserved interactions. We identified 770 mostly novel protein-protein interactions using a stringent yeast two-hybrid screen; of 75 pairs tested, 83% of the interactions were verified in mammalian cells. Many ataxia-causing proteins share interacting partners, a subset of which have been found to modify neurodegeneration in animal models. This interactome thus provides a tool for understanding pathogenic mechanisms common for this class of neurodegenerative disorders and for identifying candidate genes for inherited ataxias.

Pineal cyst apoplexy: case report and review of the literature

OBJECTIVE AND IMPORTANCE

Although most pineal cysts are clinically benign and asymptomatic, some can become symptomatic. Of the various symptomatic presentations, apoplexy is the rarest and most ill-defined. A comprehensive search of publications in the English language yielded 18 cases of pineal cyst apoplexy. We reviewed the literature to compare symptomatology and management strategies and their outcomes.

CLINICAL PRESENTATION

A 29-year-old woman with a 1-month history of headaches presented with an acute worsening of her symptoms with a severe occipital headache and trouble focusing when reading. Her neurological examination was otherwise normal. Magnetic resonance imaging showed pineal cyst apoplexy and accompanying hydrocephalus.

INTERVENTION

A left paramedian craniotomy with a transcallosal, transchoroidal approach using an intraoperative neuronavigation system was used to resect a pineal cyst. Postoperative imaging showed complete removal of the cyst and resolution of the hydrocephalus. Follow-up imaging at 12 months demonstrated no evidence of recurrence or any hydrocephalus. The patient has remained asymptomatic for 18 months.

CONCLUSION

Pineal cyst apoplexy should always be considered when following a patient with a pineal cyst that becomes symptomatic. The most common symptom was severe headache of sudden onset or acute worsening. Other signs of hydrocephalus may or may not be present. Magnetic resonance imaging is essential to making a diagnosis. Although we believe that surgical resection is the most effective approach because it minimizes the risk for recurrence and complication, stereotactic aspiration has been used successfully to treat this condition.