✓ Recent information regarding the nature of bulk cerebrospinal fluid formation and absorption is reviewed, integrated with previous knowledge, and applied to the clinical setting.
Laurence Davidson and J. Gordon McComb
✓The Pott puffy tumor is a subperiosteal abscess associated with underlying osteomyelitis, most often of the frontal bone in conjunction with frontal sinusitis. Intracranial sequelae can include epidural abscess, subdural empyema, intra-parenchymal abscess, meningitis, and dural venous thrombophlebitis, all with resultant neurological deterioration.
Although once common, this entity has become rare since the introduction of antibiotic agents. The authors present an unusual case of a 14-year-old girl suffering from the Pott puffy tumor whose condition was further complicated by a draining epidural–cutaneous fistula and an epidural abscess.
Jeffrey J. Quezada and J. Gordon McComb
The authors sought to determine the reliability of a radiopharmaceutical (RP) shunt flow study for the detection of a CSF-diverting shunt malfunction in the presence of stable ventricular size.
After the authors obtained IRB approval, all CSF RP shunt flow studies done between January 1, 2014, and January 1, 2019, in pediatric patients at Children’s Hospital Los Angeles were identified. Included in the study were only those patients in whom an MRI or CT scan was done during the hospital admission for shunt malfunction and showed no increase in ventricular size compared with the most recent prior MRI or CT scan when the patient was asymptomatic. Data recorded for analysis were patient age and sex, etiology of the hydrocephalus, shunt distal site, nonprogrammable versus programmable valve, operative findings if the shunt was revised, and follow-up findings for a minimum of 90 days after admission. The RP shunt flow study consisted of tapping the reservoir and injecting technetium-99m DTPA according to a set protocol.
The authors identified 146 RP flow studies performed in 119 patients meeting the above criteria. Four of the 146 RP studies (3%) were nondiagnostic secondary to technical failure and were excluded from statistical analysis. Of the 112 normal flow studies, operative intervention was not undertaken in 102 (91%). The 10 (9%) remaining normal studies were performed in patients who underwent operative intervention, in which 8 patients had a proximal obstruction, 1 had a distal obstruction, and 1 patient had no obstruction. Of the 30 patients with abnormal flow studies, symptoms of shunt malfunction subsided in 9 (30%) patients and these patients did not undergo operative intervention. Of the 21 (70%) operated patients, obstruction was proximal in 9 patients and distal in 5, and for 7 patients the shunt tubing was either fractured or disconnected. Regression analysis indicated a significant association between the flow study interpretation and the odds for shunt revision (OR 27, 95% CI 10–75, p < 0.0001). No other clinical variables were significant. The sensitivity of a shunt flow study alone for detection of shunt malfunction in cases with stable ventricular size was the same as a shunt flow study plus an MRI or CT (70% vs 70%), but performing a shunt flow in addition to MRI or CT did increase the specificity from 92% to 100% and the accuracy from 87% to 94%.
RP shunt flow studies were of definite value in deciding whether to operatively intervene in patients with symptoms of shunt malfunction in whom no change in ventricular size was detected on current MRI or CT scans compared to scans obtained when the patients were asymptomatic.
Laurence Davidson, Mark D. Krieger, and J. Gordon McComb
The purpose of this study was to evaluate the posterior interhemispheric retrocallosal approach (PIRA) for its safety and efficacy in the resection of pineal region and posterior fossa lesions in children.
Twenty-nine PIRAs were performed in 26 children between March 1997 and March 2009, and these cases were retrospectively reviewed. There were 15 girls and 11 boys in the series. The median age at the time of surgery was 7 years (range 7 months–17 years). Twenty-seven cases were treated for tumor, 1 for loculated hydrocephalus, and 1 for an aneurysm.
Of the 27 cases treated for tumor, there were 20 (74%) gross-total resections, 5 (19%) subtotal resections, and 2 (7%) biopsies. One bridging vein was sacrificed in 6 cases and 2 bridging veins were divided in 1 case, whereas in 3 cases there was sacrifice of a single deep cerebral vein. No patient developed radiographic evidence of venous infarction. Approach-related complications were low, and included 2 cases of transient homonymous hemianopia. There were no surgery-related deaths.
This approach allows for ample access to pineal region and posterior fossa lesions, with low postoperative morbidity.
Mark D. Krieger, Stefan Blüml, and J. Gordon McComb
Diffuse pontine gliomas in children carry a dismal prognosis, with a mean survival of less than 1 year despite therapy. The diagnosis is based on the characteristic changes demonstrated on traditional magnetic resonance (MR) imaging. A few typically MR imaging–appearing pontine masses, however, do not behave in the expected fashion, which calls the original diagnosis into question.
The authors conducted a retrospective review of data obtained in 42 children (age 6 months–13 years) in whom diffuse pontine glioma had been diagnosed at their institution. Five of these patients (12%) survived longer than expected (> 8 months). There were no differences in these patients in terms of demographics, presentation, traditional imaging findings, or treatment compared with the group as a whole. Magnetic resonance spectroscopy, however, demonstrated two distinct patterns not seen in typical diffuse pontine gliomas. In two patients elevated lipid and lactate levels were shown, with decreased levels of choline, myoinositol, and n-acetyl-aspartate (NAA). In the other patients strikingly elevated choline/creatinine ratios and myoinositol levels were observed in comparison with typical pontine tumors.
These MR spectroscopy patterns demonstrated in this retrospective study seem to convey prognostic information and may lead to an expansion of this diagnostic tool.
Michael L. Chen, J. Gordon McComb, and Mark D. Krieger
Atypical teratoid/rhabdoid tumors (ATRTs) represent a relatively newly categorized neoplastic entity. They commonly present in childhood, and have a rapidly progressive clinical course with a survival time of less than 1 year. Treatment regimens have been nonuniform. In this retrospective review of patients with ATRTs who were treated at the authors' institution according to a uniform protocol, the goal was to assess the efficacy of the treatment and its outcome.
Over a 7-year period, ATRT was diagnosed in 11 patients (six boys and five girls). The median age of the patients was 61 months, and their ages ranged from 3 months to 17 years. Signs and symptoms began, on average, a little more than 1 month before diagnosis and included the following: headache (36%), nausea and vomiting (46%), lethargy (18%), seizures (27%), cranial nerve findings (46%), ataxia (18%), long tract findings (18%), and hydrocephalus (46%). Tumor location was cortical in four patients, in the pineal region in four, in the posterior fossa in two, and spinal in one. In one patient disseminated disease was revealed on the initial imaging study; seven patients had disseminated tumor subsequently. Treatment consisted of chemotherapy in 11 patients, chemotherapy and local radiation in five, and chemotherapy and craniospinal radiation in three. Six patients are alive, three have died, and two were lost to follow-up review. The mean time to death was 24 months, and ranged from 2 to 67 months. Among the surviving patients the mean duration of follow up is 18.5 months and ranges from 2 to 37 months. The median time to progression was 3.5 months.
Atypical teratoid/rhabdoid tumors are malignant lesions with rapid progression. Further study is necessary to determine the efficacy of therapy.
Howard M. Eisenberg, J. Gordon McComb, and Antonio V. Lorenzo
✓ With the use of a ventricular perfusion technique, a cerebrospinal fluid formation rate of 1.4 ml/min was determined in a 5-month-old child with a choroid plexus papilloma and hydrocephalus. This rate was slightly greater than four times the rate observed in normal children. The clinical course, as well as a measured absorption rate, indicated that the patient's capacity for absorption was normal.
W. Jerry Oakes
David I. Sandberg, J. Gordon McComb, and Mark D. Krieger
The authors analyzed the chemical composition of intracranial arachnoid cyst fluid to gain greater understanding of potential causes of cyst growth.
The authors studied 54 pediatric patients who underwent craniotomies for arachnoid cyst fenestration. Cyst fluid was analyzed and results were compared with expected values (EVs) for cerebrospinal fluid (CSF).
The arachnoid cyst fluid values were as follows: protein (median 37 mg/dl, mean 178.2 mg/dl, and EV 25.6 mg/dl), osmolality (median 284 mOsm/kg, mean 285.5 mOsm/kg, and EV 287.2 mOsm/kg), potassium (median 2.6 mEq/L, mean 2.68 mEq/L, and EV 2.88 mEq/L), sodium (median 140 mEq/L, mean 142.2 mEq/L, and EV 143.3 mEq/L), and chloride (median 122 mEq/L, mean 120.77 mEq/L, and EV 120.3 mEq/L). Median glucose was 51 mg/dl (range 26–98 mg/dl). The median white blood cell count in cyst fluid was 1/mm3, and the median red blood cell (RBC) count was 1.5/mm3. All Gram stains and cultures were negative.
No statistically significant correlations were found between arachnoid cyst fluid protein level and elevated RBC count, patient age, or the subsequent need for a shunt. Elevated RBC count in cyst fluid was also not associated with the subsequent need for a shunt.
Fluid from arachnoid cysts has a chemical composition similar to that of CSF, but some of them have significantly elevated protein levels. The authors hypothesize that elevated protein content may contribute to arachnoid cyst expansion in some patients.