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Sandeep Sood, Cherukuri Ravi Kumar, Mohammad Jamous, Martin U. Schuhmann, Steven D. Ham and Alexa I. Canady

Object. Patients undergoing long-term shunt therapy following shunt malfunction often present with acute neurological deterioration, high intracranial pressure (ICP), and yet small or slit ventricles. It is believed that low brain compliance prevents ventricle enlargement in such cases. To elucidate the underlying pathophysiology, the authors estimated compliance as a function of cerebrovascular distensibility in 45 patients undergoing chronic shunt therapy.

Methods. The ICP and pressure—volume index (PVI) were measured at end-tidal CO2 of 30 mm Hg (PVI30) and 40 mm Hg (PVI40). The ventricle volume was dichotomized as slit/small/normal or dilated based on the frontooccipital horn ratio. In 18 patients PVI30 was normal (18.4 ± 4 ml), whereas in 27 patients it was significantly elevated (45.5 ± 14 ml). Clinical symptoms or ventricle size at presentation did not correlate with the PVI30. The ICP and PVI at end-tidal CO2 of 40 mm Hg were significantly higher than those at end-tidal CO2 of 30 mm Hg (p < 0.001 and < 0.02, respectively) suggesting an increased cerebrovascular distensibility.

Conclusions. The authors did not observe a low compliance in patients undergoing chronic shunt therapy who, at shunt malfunction, presented with a slit/small/normal ventricle; however, analysis of the findings strongly indicated that an increased cerebrovascular distensibility was present in these patients. This may explain the high ICP and acute clinical deterioration following shunt malfunction in such cases.

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Ramin Eskandari, James P. McAllister II, Janet M. Miller, Yuchuan Ding, Steven D. Ham, David M. Shearer and John S. Way

Object. The authors of previous studies have suggested that connectivity within the cerebral cortex may be irreversibly altered by hydrocephalus. To examine connectivity-related changes directly, the authors conducted a study in which they used an axonal tracer in an animal model of infantile hydrocephalus.

Methods. In five hydrocephalic kittens low-pressure ventriculoperitoneal (VP) shunts were placed 10 to 14 days after induction of hydrocephalus by intracisternal kaolin injections. Wheat germ agglutinin-conjugated horseradish peroxidase was injected laterally into the motor cortex in hydrocephalic animals 9 to 15 days after kaolin injection, and 1, 2, and 4 weeks after VP shunt insertion in shunt-treated animals, and in age-matched controls.

Reduction of antero- and retrograde labeling was most profound within the contralateral cortex and portions of the midbrain. Thalamic nuclei exhibited reductions in anterograde and retrograde labeling. Labeling within cell bodies of the ventral tegmental area decreased greatly in animals with untreated hydrocephalus, in which retrograde labeling was reduced in the locus coeruleus but did not affect the raphe nucleus. Shunt treatment increased both antero- and retrograde labeling of contralateral motor cortex to near-normal levels. Thalamic relay nuclei recovered antero- and retrograde labeling, although not to levels exhibited in controls. Shunt therapy restored cellular labeling within the ventral tegmental area and locus coeruleus. Recovery of labeling occurred as early as 7 days after shunt insertion.

Conclusions. Collectively, analysis of these data indicates the following. 1) Cortical connectivity involving both afferent and efferent pathways was impaired in untreated hydrocephalic animals. 2) Shunt therapy improved both cortical afferent and efferent connectivity. 3) Complete reestablishment of the cortical efferent pathways, however, did not occur. Cortical pathway dysfunction, if permanent, could cause many of the motor and cognitive deficits seen clinically in children with hydrocephalus.

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Sandeep Sood, Martin U. Schuhmann, Nedim Cakan and Steven D. Ham

P The authors describe their experience with endoscopic fenestration of suprasellar cysts followed by shrinkage coagulation of the cysts to restore the anatomy in eight patients.

Seven children ranging in age from 8 months to 4.5 years and one adult 24 years of age were treated. Four of the children presented with megacephaly and the other patients with malfunction of a shunt that had been placed previously for hydrocephalus. Endoscopic fenestration of the cyst dome was performed followed by shrinkage of the lesion by means of endoscopic coagulation. Follow-up studies included immediate and late postoperative magnetic resonance imaging, assessment of growth velocity and the body mass index (BMI), and an endocrine profile if indicated by a failure of growth or precocious puberty.

Good intraoperative cyst shrinkage was achieved in all seven children. This was maintained on imaging studies at a mean follow-up period of 35 months. There was no significant procedure-associated morbidity. Hydrocephalus resolved in four patients who did not have a preexisting shunt. One of the four patients who had a shunt preoperatively became shunt free. The rest of the patients with preexisting shunts remained shunt dependent despite good resolution of the cyst. During a mean follow-up period of 52 months, the height, growth velocity, and BMI of each patient remained within two standard deviations of normal. In one patient there was a suspicion of precocious puberty, but the endocrine profile was normal; in another patient precocious puberty developed and required treatment.

The presented technique is safe and prevents cyst recurrence and obstruction of the aqueduct by remnants of the cyst wall—the two main reasons for failure of a simple endoscopic fenestration.

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Sandeep Sood, Jaliya Lokuketagoda and Steven D. Ham

Object. The failure of ventricles to enlarge after acute shunt malfunction in long-term shunt-dependent patients is generally attributed to the presence of periventricular rigidity resulting from gliosis. The aim of this study was to test the hypothesis that periventricular rigidity is present in these patients.

Methods. Fifteen pediatric patients who presented with acute shunt malfunction were studied; slit ventricles were detected in all of these patients. Pressure measurements were recorded simultaneously in both the ventricle and the brain parenchyma during shunt revision and then repeated after bolus infusion of fluid into the ventricle.

The mean intraventricular pressure (IVP) at presentation was 24.1 mm Hg (standard deviation 10 mm Hg). The mean baseline IVP after drainage of cerebrospinal fluid but prior to the infusion was 7.5 ± 4.3 mm Hg. There was no significant difference in the increase in the IVP and the intraparenchymal pressure (IPP) after bolus infusion into the ventricle (3.6 ± 2.4 mm Hg and 3.3 ± 2.1 mm Hg, respectively; p = 0.39). The mean pressure volume index was 24.1 ml (standard error of the mean 4.6 ml).

Conclusions. The profile of the changes in IVP and IPP indicates that the periventricular wall does not restrict ventricular enlargement following shunt malfunction in long-term shunt-dependent patients.

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Sandeep Sood, Jaliya Lokuketagoda and Steven D. Ham

Object

The failure of ventricles to enlarge after acute shunt malfunction in long-term shunt-dependent patients is generally attributed to the presence of periventricular rigidity resulting from gliosis. The aim of this study was to test the hypothesis that periventricular rigidity is present in these patients.

Methods

Fifteen pediatric patients who presented with acute shunt malfunction were studied; slit ventricles were detected in all of these patients. Pressure measurements were recorded simultaneously in both the ventricle and the brain parenchyma during shunt revision and then repeated after bolus infusion of fluid into the ventricle.

The mean intraventricular pressure (IVP) at presentation was 24.1 mm Hg (standard deviation 10 mm Hg). The mean baseline IVP after drainage of cerebrospinal fluid but prior to the infusion was 7.5 ± 4.3 mm Hg. There was no significant difference in the increase in the IVP and the intraparenchymal pressure (IPP) after bolus infusion into the ventricle (3.6 ± 2.4 mm Hg and 3.3 ± 2.1 mm Hg, respectively; p = 0.39). The mean pressure volume index was 24.1 ml (standard error of the mean 4.6 ml).

Conclusions

The profile of the changes in IVP and IPP indicates that the periventricular wall does not restrict ventricular enlargement following shunt malfunction in long-term shunt-dependent patients.

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Sandeep Sood, Ryan J. Barrett, Tiffany Powell and Steven D. Ham

Object

Slit-ventricle syndrome (SVS) is a confusing description of presentations in patients with chronic shunt-treated hydrocephalus. These patients are prone to acute deterioration with recurrent malfunction. The authors describe the clinical profile and management outcome of using lumboperitoneal (LP) shunts in this population of patients.

Methods

Thirty-three patients with slit ventricles and recurrent malfunctions were converted to LP shunts (mean age 12 years). The initial ventricular shunt was placed at a mean age of 16.5 months. Ten patients had failed endoscopic third ventriculostomies prior to placement of their LP shunt. At a previous presentation, in 11 patients suspected to have SVS following revision of the shunt, intracranial pressure normalized after insertion of a contralateral shunt, suggesting that their ventricles were isolated. The rate of infection and malfunction was compared before and after conversion to an LP shunt.

Twenty-seven patients were successfully converted to LP shunts. Four of the 11 patients with isolated ventricles required ventricular shunts in addition to the LP shunt. During a mean follow-up period of 16.7 months, the malfunction rate per patient decreased from 4.81 for ventriculoperitoneal shunts, prior to conversion to 1.48 after conversion to LP shunts, a statistically significant reduction (p < 0.000). No significant difference was found in the rate of shunt infections (7.1% for VP shunts and 9.6% for LP shunts, p = 0.44). No patient presented with acute symptoms following malfunction of an LP shunt or suffered from a Chiari I malformation.

Conclusions

Conversion to an LP shunt is a safe and effective procedure in patients prone to rapid decompensation and recurrent shunt malfunctions from small, slitlike ventricles. The term SVS is confusing. The condition is a manifestation of an unrecognized slitlike isolated ventricle and should be abandoned.

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Martin U. Schuhmann, Kimberly R. Ostrowski, Emily J. Draper, Jau-Wen Chu, Steven D. Ham, Sandeep Sood and James P. McAllister

Object

Shunt infections and their management remain a clinically important problem in patients with hydrocephalus. The authors evaluated, in comparison with traditional parameters, C-reactive protein (CRP) in blood/serum (S-CRP) and in cerebrospinal fluid (CSF; C-CRP) for its power to identify and treat patients with infected shunts.

Methods

On 84 different occasions, CSF and blood samples from 59 children suspected of having shunt/CSF infections were obtained and evaluated. An infection was proven by a CSF culture in 35 of 84 evaluations. Values for S-CRP in infected individuals were higher than in noninfected ones (91.8 ± 70.2 mg/L compared with 16.1 ± 28.3 mg/L, p < 0.0001). The sensitivity of S-CRP testing was 97.1%, the specificity 73.5%, the negative predictive value 97.3%, and the receiver operating characteristic area 91.6%. The probability of shunt/CSF infection—provided that the S-CRP level was greater than 7 mg/L—rose from 41.7% (prevalence) to a posttest level of 72.3%. Specificity and posttest probability were 87.8 and 87.2%, respectively, if cases with other concurrent infections were excluded. The probability of missing a CSF/shunt infection at an S-CRP lower than 7 mg/L was 2.7%. All other diagnostic parameters did not yield useful test results. The rate of reinfection was elevated in patients in whom S-CRP levels were greater than 7 mg/L at the time of shunt reimplantation.

Conclusions

Analysis of these data suggests that the S-CRP level should be included in the first-line workup of patients with suspected shunt/CSF infection. It seems justified to avoid performing a shunt tap if S-CRP levels are less than 7 mg/L. A larger multicenter trial is necessary to confirm these promising diagnostic results and to deliver hard data concerning whether or not a normalized S-CRP level is a reliable indicator of successful antibiotic therapy and whether a shunt can be safely reimplanted.

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Sandeep Sood, Holly Gilmer-Hill and Steven D. Ham

Object

The aim of this study was to define the origin and management of lumbar shunt site swelling/cerebrospinal fluid (CSF) leak seen in children who underwent placement of a percutaneous lumbar shunt due to recurrent problems with a ventricular shunt.

Methods

Fifty-seven children with a lumbar shunt were analyzed. Episodes of swelling along the lumbar shunt site, presenting symptoms, origin of the CSF leak, and surgical outcome were recorded.

Results

Twenty patients had 30 episodes of CSF leak/swelling at a mean interval of 92 ± 233 days (± standard deviation) after placement or revision. There were 7 episodes of an external CSF leak; 5 of marked swelling; and 18 episodes of headache, dizziness, and swelling. In 4 patients, the cause of CSF leakage was a fracture/disconnection or dislocation of the proximal catheter. In the remaining patients, CSF leakage was from around the proximal catheter entry point into the spinal dura (with a rate of 16.9% for placement and 15.7% for revision/reinsertion). Interlaminar removal of the existing catheter, microsurgical repair of the leak, and replacement through an opening made with the stylet of a 14-gauge Tuohy needle (Medtronic Neurosurgery) was most effective compared with percutaneous blood patch, pericatheter fascial suture, and percutaneous repositioning of the proximal catheter or downgrading valve pressure.

Conclusions

Lumbar shunt site swelling is predominantly a consequence of pericatheter CSF leakage from the mismatch in the dural opening, which corresponds to the outer diameter of the 14-gauge Tuohy needle and the smaller proximal lumbar catheter. It is best managed by direct repair of the defect through a microsurgical interlaminar approach and recannulation of the dura by using only the stylet of a 14-gauge Tuohy needle.

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Norka Wilkinson, Sandeep Sood, Steven D. Ham, Holly Gilmer-Hill, Patricia Fleming and Madhvi Rajpurkar

Object

In this single-center study, the authors examined the clinical characteristics, risk factors, treatment strategies, and outcomes in patients with thrombosis associated with ventriculoatrial (VA) shunts.

Methods

Inpatient and outpatient charts of patients who underwent treatment and follow-up in the Hematology-Oncology Division at the authors' institution and in whom thrombosis developed secondary to a VA shunt placement were reviewed. A complete thrombophilia work-up was performed in each patient, and these records were also reviewed. Treatment including medical and surgical management was noted and outcome data were recorded.

Results

Resolution of thrombosis was seen after anticoagulation therapy in all patients; this may be an alternative to surgical therapy.

Conclusions

Patients with VA shunts represent a unique group at risk for thrombosis. The duration of anticoagulation therapy must be individualized. However, larger studies are needed to evaluate the efficacy of screening for asymptomatic thrombosis and to investigate the role of prophylactic anticoagulation.

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Chaim B. Colen, Mahmoud Rayes, Jamal McClendon Jr., Raja Rabah and Steven D. Ham

In this report the authors describe a unique case of spinal clear cell meningioma in a 13-year-old girl. Clear cell meningiomas (CCMs) are not uncommon. To the authors' knowledge, 14 cases of pediatric CCM occurring in the spinal canal have been reported. Factors lending resistance to meningioma initiation and invasion are analyzed. This 13-year-old girl presented with pain radiating down her left leg. Admission MR imaging showed an inhomogeneous enhancing intradural-extramedullary mass at the L4–5 level. Resection revealed a CCM, and radiotherapy was subsequently administered. Postoperatively there has been no recurrence in > 2 years. In this paper the authors report a case of CCM and provide a comprehensive literature review on this disease. Current recommendations for its management are still debatable, especially in the pediatric population, and the authors propose an algorithm for its treatment and surveillance.