Wajd N. Al-Holou

Prevalence and natural history of arachnoid cysts in children.

OBJECT Arachnoid cysts are a frequent finding on intracranial imaging in children. The prevalence and natural history of these cysts are not well defined. The authors studied a large consecutive series of children undergoing MR imaging to better define both the MR imaging-demonstrated prevalence and behavior of these lesions over time. METHODS The authors reviewed a consecutive series of 11,738 patients who were 18 years of age or younger and had undergone brain MR imaging at a single institution during an 11-year period. In the patients in whom intracranial arachnoid cysts were identified, clinical and demographic information was recorded and imaging characteristics, such as cyst size and location, were evaluated. Prevalence data were analyzed using univariate and multivariate logistic regression, linear regression, and ANOVA. All patients with sufficient data (repeat MR imaging studies as well as repeated clinical evaluation over at least 5 months) for a natural history analysis were identified. This group was assessed for any change in symptoms or imaging appearance during the follow-up interval. RESULTS Three hundred nine arachnoid cysts (2.6% prevalence rate) were identified. There was an increased prevalence of arachnoid cysts in males (p < 0.000001). One hundred eleven patients met all criteria for inclusion in the natural history analysis. After a mean follow-up of 3.5 years, 11 arachnoid cysts increased in size, 13 decreased, and 87 remained stable. A younger age at presentation was significantly associated with cyst enlargement (p = 0.001) and the need for surgery (p = 0.05). No patient older than 4 years of age at the time of initial diagnosis had cyst enlargement, demonstrated new symptoms, or underwent surgical treatment. CONCLUSIONS Arachnoid cysts are a common incidental finding on intracranial imaging in pediatric patients. An older age at the time of presentation is associated with a lack of clinical or imaging changes over time.

Comparison of the accuracy of ventricular catheter placement using freehand placement, ultrasonic guidance, and stereotactic neuronavigation.

OBJECT The objective of this study was to compare the accuracy of 3 methods of ventricular catheter placement during CSF shunt operations: the freehand technique using surface anatomy, ultrasonic guidance, and stereotactic neuronavigation. METHODS This retrospective cohort study included all patients from a single institution who underwent a ventricular CSF shunting procedure in which a new ventricular catheter was placed between January 2005 and March 2010. Data abstracted for each patient included age, sex, diagnosis, method of ventricular catheter placement, site and side of ventricular catheter placement, Evans ratio, and bifrontal ventricular span. Postoperative radiographic studies were reviewed for accuracy of ventricular catheter placement. Medical records were also reviewed for evidence of shunt failure requiring revision through December 2011. Statistical analysis was then performed comparing the 3 methods of ventricular catheter placement and to determine risk factors for inaccurate placement. RESULTS There were 249 patients included in the study; 170 ventricular catheters were freehand passed, 51 were placed using stereotactic neuronavigation, and 28 were placed under intraoperative ultrasonic guidance. There was a statistically significant difference between freehand catheters and stereotactic-guided catheters (p<0.001), as well as between freehand catheters and ultrasound-guided catheters (p<0.001). The only risk factor for inaccurate placement identified in this study was use of the freehand technique. The use of stereotactic neuronavigation and ultrasonic guidance reduced proximal shunt failure rates (p<0.05) in comparison with a freehand technique. CONCLUSIONS Stereotactic- and ultrasound-guided ventricular catheter placements are significantly more accurate than freehand placement, and the use of these intraoperative guidance techniques reduced proximal shunt failure in this study.

Prevalence of pineal cysts in children and young adults. Clinical article.

OBJECT Pineal cysts are a frequent incidental finding on intracranial imaging. In adults, the prevalence of pineal cysts is estimated to be 1.1-4.3%. However, the prevalence is not well established in younger patients. METHODS The authors retrospectively reviewed a consecutive series of 14,516 patients 25 years of age and younger, who underwent brain MR imaging at a single institution over an 11-year period. In patients identified with pineal cysts, the authors analyzed the images according to cyst size, signal characteristics, enhancement pattern, and evidence of local mass effect. Patient characteristics including demographics and other intracranial diagnoses were collected in the pineal cyst population and compared with a randomly selected age- and sex-matched control patient population. The data were evaluated using univariate and multivariate logistic regression, linear regression, and ANOVA. RESULTS The authors identified 288 pineal region cysts (2.0%). The prevalence of pineal cysts was higher in female (2.4%) than in male patients (1.5%; p < 0.001). Pineal cysts were identified in patients of all ages, with an increased prevalence found in older patients (p < 0.001). Pineal cyst size was similar for all age and sex groups. CONCLUSIONS Pineal cysts are common in the pediatric population, with an increased prevalence in girls and in older patients.

The natural history of pineal cysts in children and young adults: Clinical article

OBJECT The authors reviewed their experience with pediatric pineal cysts to define the natural history and clinical relevance of this common intracranial finding. METHODS The authors identified all patients with pineal cysts who had been clinically evaluated at their institution over an 11.5-year interval and were < 25 years of age at the time of diagnosis. All inclusion criteria were met in 106 patients, and included repeated MR imaging as well as repeated clinical evaluation over at least a 6-month interval. RESULTS The mean age at diagnosis was 11.7 +/- 7.2 years. Forty-two patients were male and 64 were female. On follow-up MR imaging evaluation at a mean interval of 3.0 years from the initial study, 98 pineal cysts had no increase in size and no change in imaging appearance. Six pineal cysts increased in size and 2 others had a change in imaging characteristics without associated growth. Younger age was associated with cyst change or growth on follow-up imaging (p = 0.02). The mean age of patients with cysts that changed or grew was 5.5 years, and the mean age of patients with stable pineal cysts was 12.2 years. Initial cyst size and appearance on MR imaging were not significant predictors of growth or change in imaging appearance at follow-up. Similarly, the patients sex was not a significant predictor of growth or change in imaging characteristics. CONCLUSIONS Follow-up imaging and neurosurgical evaluation may be considered optional in older children with pineal cysts.

The outcome of tethered cord release in secondary and multiple repeat tethered cord syndrome: Clinical article

OBJECT After primary repair of a myelomeningocele or a lipomyelomeningocele, patients can present with symptoms of secondary tethered cord syndrome (TCS). After surgical untethering, a small percentage of these patients can present with multiple repeat TCS. In patients presenting with secondary or multiple repeat TCS, the role as well the expected outcomes of surgical untethering are not well defined. METHODS Eighty-four patients who underwent spinal cord untethering after at least 1 primary repair were retrospectively evaluated using scaled and subjective outcome measures at short-term and long-term follow-up visits. Outcomes were analyzed for predictive measures using multivariate logistic regression. RESULTS Surgical untethering was performed in 66 patients with myelomeningoceles and 18 patients with lipomyelomeningoceles. Fourteen patients underwent multiple repeat spinal cord untethering. Patients were followed up for an average of 6.2 years. Most patients had stability of function postoperatively. Motor function and weakness improved in 7 and 16% of patients at 6 months, respectively, and 6 and 19% of patients at long-term follow-up evaluation, respectively. Of the patients who presented with back pain, 75% had improvement in symptoms at 6 months postoperatively. Younger age at untethering was significantly associated with worse long-term neurological outcomes. The number of previous untethering procedures, original diagnosis, sex, anatomical level, and degree of untethering had no effect on surgical outcomes. CONCLUSIONS Patients presenting with secondary or multiple repeat TCS may benefit from surgical untethering.

Prevalence and natural history of pineal cysts in adults

OBJECT We reviewed our experience with pineal cysts to define the natural history and clinical relevance of this common intracranial finding. METHODS The study population consisted of 48,417 consecutive patients who underwent brain MR imaging at a single institution over a 12-year interval and who were over 18 years of age at the time of imaging. Patient characteristics, including demographic data and other intracranial diagnoses, were collected from cases involving patients with a pineal cyst. We then identified all patients with pineal cysts who had been clinically evaluated at our institution and who had at least 6 months of clinical and imaging follow-up. All inclusion criteria for the natural history analysis were met in 151 patients. RESULTS Pineal cysts measuring 5 mm or larger in greatest dimension were found in 478 patients (1.0%). Of these, 162 patients were male and 316 were female. On follow-up MR imaging of 151 patients with pineal cyst at a mean interval of 3.4 years from the initial study, 124 pineal cysts remained stable, 4 increased in size, and 23 decreased in size. Cysts that were larger at the time of initial diagnosis were more likely to decrease in size over the follow-up interval (p = 0.004). Patient sex, patient age at diagnosis, and the presence of septations within the cyst were not significantly associated with cyst change on follow-up. CONCLUSIONS Follow-up imaging and neurosurgical evaluation are not mandatory for adults with asymptomatic pineal cysts.

Single center review of femoral arteriovenous grafts for hemodialysis.

IntroductionIt is unclear how to manage high risk hemodialysis patients who present with an indwelling catheter. The National Kidney Foundation Practice Guidelines urge prompt removal of the catheter, but the guidelines do not specifically address the problem of patients whose only option is a femoral arteriovenous (AV) graft.MethodsThis study was a retrospective review of all patients who underwent femoral AV graft placement for hemodialysis access between January 1, 1996 and January 1, 2003 at the University of Michigan Health System (UMHS). Graft patency is reported according to the standards developed by the Society of Vascular Surgery and the American Association of Vascular Surgeons.ResultsThirty patients were identified who had undergone femoral AV graft placement. The mean follow-up was 23 months (range 1–75 months). The patients had had significant medical co-morbidities and multiple previous access operations (mean 3; interquartile range 1–5). The 1-year secondary graft patency rate was 41%, the 2-year rate was 26%, and the 3-year rate was 21%. Infection was the cause of final graft loss in eight patients (50% of the grafts losses, 27% of the total grafts placed.) Among those who died (n = 14), the mean time from femoral graft placement to death was 31.2 ± 27.5 months. The patient survival was quite low: at 1 year 81%, at 2 years 68%, and at 3 years 54%.ConclusionsThese complex patients who have exhausted their upper extremity hemodialysis options do poorly following femoral AV graft placement. Consideration should be given to long-term catheter-based access in some of these patients.

Filum terminale lipomas: imaging prevalence, natural history, and conus position

OBJECT Filum terminale lipomas (FTLs) are being identified with increasing frequency due to the increasing utilization of MRI. Although an FTL may be associated with tethered cord syndrome (TCS), in many cases FTLs are diagnosed incidentally in patients without any symptoms of TCS. The natural history of FTLs is not well defined. METHODS The authors searched the clinical and imaging records at a single institution over a 14-year interval to identify patients with FTLs. For patients with an FTL, the clinical records were reviewed for indication for imaging, presenting symptoms, perceived need for surgery, and clinical outcome. A natural history analysis was performed using all patients with more than 6 months of clinical follow-up. RESULTS A total of 436 patients with FTL were identified. There were 217 males and 219 females. Of these patients, 282 (65%) were adults and 154 (35%) were children. Symptoms of TCS were present in 22 patients (5%). Fifty-two patients underwent surgery for FTL (12%). Sixty-four patients (15%) had a low-lying conus and 21 (5%) had a syrinx. The natural history analysis included 249 patients with a mean follow-up time of 3.5 years. In the follow-up period, only 1 patient developed new symptoms. CONCLUSIONS Filum terminale lipomas are a common incidental finding on spinal MRI, and most patients present without associated symptoms. The untreated natural history is generally benign for asymptomatic patients.

Traumatic lateral spondylolisthesis of the lumbar spine with a unilateral locked facet: Description of an unusual injury, probable mechanism, and management: Report of two cases

Primary traumatic facet dislocations are unusual in the lumbar spine. Most occurrences have been reported at the lumbosacral junction associated with anterior subluxation. The authors describe 2 cases in which a high impact trauma resulted in lateral subluxation with a unilateral locked facet involving the lumbar spine. In their review of the literature, the authors found no previously reported cases of this type of injury. Both cases described in this report involved significant spinal stenosis, neurological injury, and spinal instability. A posterior surgical approach, with at least partial resection of the locked facet joint in conjunction with pedicle screw fixation, allowed successful reduction and stabilization of the injury.

Management of subdural hygromas associated with arachnoid cysts

OBJECT Arachnoid cysts may occasionally be associated with subdural hygromas. The management of these concurrent findings is controversial. METHODS The authors reviewed their experience with arachnoid cysts and identified 8 patients with intracranial arachnoid cysts and an associated subdural hygroma. The medical records and images for these patients were also examined. RESULTS In total, 8 patients presented with concurrent subdural hygroma and arachnoid cyst. Of these 8 patients, 6 presented with headaches and 4 had nausea and vomiting. Six patients had a history of trauma. One patient was treated surgically at the time of initial presentation, and 7 patients were managed without surgery. All patients experienced complete resolution of their presenting signs and symptoms. CONCLUSIONS Subdural hygroma may lead to symptomatic presentation for otherwise asymptomatic arachnoid cysts. The natural course of cyst-associated subdural hygromas, even when symptomatic, is generally benign, and symptom resolution can be expected in most cases. The authors suggest that symptomatic hygroma is not an absolute indication for surgical treatment and that expectant management can result in good outcomes in many cases.