Impact of dose hot spots on spinal cord tolerance following stereotactic body radiotherapy: a generalized biological effective dose analysis.

The purpose of this study was to investigate the effects of high-dose inhomogeneous irradiation to small volumes of spinal cord with a new generalized biological effective dose (gBED) analysis for spine stereotactic body radiotherapy (SBRT). The gBED was applied to spinal cord dosimetric data (contoured per the thecal sac) at specified volumes for a cohort of five patients with radiation-induced myelopathy (RM) and compared to nineteen patients without RM post-SBRT. The spinal cord gBED was calculated and normalized to a conventional 2-Gy equivalent dose fraction scheme (α/ß = 2 Gy for late toxicity). Differences between the conventional BED and those gBED calculations by accounting for small-volume dosing within the spinal cord was observed. Statistically significant differences in the mean gBED between the RM group and the non-RM group was observed both at the maximum point volume (gBED of 66 Gy vs. 37 Gy (p = 0.01), respectively) and at the 0.1 cm(3) volume (gBED of 53 Gy vs. 28 Gy (p = 0.01), respectively). No significant difference at the 0.1 cm(3) volume was observed based on the mean BED comparisons. No significant differences were observed at the larger 1 cm(3), 2 cm(3) or 5 cm(3) volumes for either BED or gBED comparisons. We conclude that differences in dose hot spots characteristics within small inhomogenously irradiated volumes of spinal cord can affect spinal cord tolerance following SBRT treatments.

Provocation lumbar diskography at previously fused levels.

Recurrent or persistent low back pain (LBP) after lumbar fusion can be related to many factors. We reviewed the provocation lumbar diskogram (PLD) features and redo-fusion outcome in our patients evaluated for recurrent/persistent LBP after technically successful fusion. LD was performed in 27 patients with recurrent/persistent LBP after prior successful lumbar surgical fusion (31 fused levels: single-level fusion-23; two-level fusion-4). PLD response and imaging characteristics at fused and non-fused levels were assessed including: intra-diskal lidocaine response, diskogram-image/post-diskogram CT appearance, presence/absence of diskographic contrast leakage, and evidence of fusion integrity or hardware failure. Outcomes in patients having redo-fusion were assessed. Concordant pain was encountered at 15 out of 23 (65%) single-level fusions, non-concordant pain in one fusion with non-painful response in seven. Adjacent-level concordant pain was identified in seven out of 23 (30%) patients (three of 15 with painful fused levels; four of seven with non-painful fusions). In two-level fusions, concordant pain was encountered at one fused level in each patient. In painful fused levels, leaking and contained disks were encountered with partial or complete pain elimination after intra-diskal lidocaine injection. In anterior fusions, space or contrast surrounding the cage was noted at five of 11 levels. Pseudoarthrosis was noted only with trans-sacral screw fusions. Redo-fusion in 13 patients resulted in significant improvement in nine and moderate improvement in one. Patients with recurrent/persistent LBP after technically successful fusion may have a diskogenic pain source at the surgically fused or adjacent level confirmed by lidocaine-assisted PLD.

Epidermoid cyst of the thoracic spine: case history.

Epidermoid cysts of the spinal cord are very rare tumors. We report a 31 year-old female who presented with a 5 months history of progressive lower extremity weakness and spasticity. Magnetic resonance imaging of the thoracic spine revealed a 2 cm intradural, extramedullary mass at the T4-5 level. A T4 and T5 osteoplastic laminotomy with complete removal of the intradural mass was performed. Intraoperative and final histological examination revealed an epidermoid cyst. Epidermoid cysts must be a consideration for intradural, extramedullary lesions of the spinal cord. Complete surgical resection offers the patient an opportunity for good neurologic outcome.

Diseases of the spine in South American mummies.

OBJECTIVE: The skulls and spinal columns of people from ancient civilizations, which frequently are found in a preserved state at archeological sites, can provide a large amount of information about these individuals' physical condition through paleopathological investigation. METHODS: This study represents the examination of more than 700 human remains dating back more than 8000 years that were recovered from archaeological excavations in the Andean region of southern Peru and northern Chile. RESULTS: Examples of congenital malformations, degenerative processes, infectious diseases, neoplasias, and traumatic diseases were discovered. Congenital anomalies such as spina bifida occulta were relatively common in these populations. No cases of meningomyelocele were discovered. The most common pathological findings were degenerative changes of the vertebral bodies. Large cervical and lumbar osteophytes were identified in some remains. Several cases of cervical spondylosis were determined to be the result of an occupational disease resulting from carrying heavy loads on the back. These heavy loads were supported by wearing around the forehead a tumpline, known as a capacho. The most common infectious disease process in the spine was due to tuberculosis. The diagnosis was made by radiological and histopathological studies, and in several cases the organism Mycobacterium tuberculosis was identified in the soft tissues. Metastatic lesions on the vertebral bodies were identified in a single case. Examples of traumatic spinal injury were rare. Compression fractures were noted infrequently. CONCLUSION: Diseases of the spinal column in the ancient inhabitants of the Andean region of South America were similar to those that affect the present-day population of that area.

Current surgical management of metastatic spinal disease.

Despite advances in the treatment of many malignancies, a large number of cancer patients will require evaluation and possible surgical intervention for lesions that have metastasized or directly invaded the spinal column. The need for heightened awareness of and aggressive early intervention for spinal metastases is underscored by many studies that have reported a relationship between pretreatment and posttreatment neurologic function in these patients. Recommendations for operative intervention should be made following an evaluation of the patient by multiple specialties, both medical and surgical. In the last decade, advances in surgical techniques for tumor decompression and spine stabilization, neurophysiologic monitoring, and anesthetic expertise have allowed surgeons to perform more extensive procedures with improved outcomes and reduced morbidity. This article will review the factors favoring an operative recommendation in patients with metastatic spinal disease, preoperative evaluation, and available surgical options. Patients with symptomatic spinal metastases should receive early surgical consultation as part of a multidisciplinary approach to their disease process.

Inhibition of peridural fibrosis after laminectomy using low-dose external beam radiation in a dog model.

OBJECTIVE: Clinical studies have demonstrated a significant association between the presence of extensive postlumbar discectomy peridural scar formation and the recurrence of low back and radicular pain. Low-dose perioperative radiation therapy has previously been demonstrated to inhibit peridural fibrosis after laminectomy in a rat model. The current study was designed to measure the effect of low-dose radiation on postlaminectomy peridural fibrosis development in a larger animal model. METHODS: Three dogs underwent a total of 12 lumbar hemilaminectomies. For each animal, two levels received 1) external beam radiation 24 hours before surgery, 2) surgery alone, or 3) radiation alone. Radiation was administered in a single fraction of 700 cGy using computed tomographic guidance for dosimetry planning. The isodose distribution was such that the dose conformed to the posterior epidural space with minimal exit dose to normal tissue. Port films were used to confirm the correct levels. Gadolinium-enhanced magnetic resonance imaging (MRI) of the lumbar spines was obtained before the animals were killed 12 weeks after surgery. The spines were harvested, and axial sections through the laminectomy defect were stained with hematoxylin and eosin and Masson's trichrome. All specimens were evaluated for extent of fibrosis along the dura, density of fibrosis, nerve root entrapment, and sublaminar fibrosis. RESULTS: There were no complications from the surgery, and no new neurological deficits were noted. There was a statistically significant difference between the irradiated and nonirradiated groups regarding the extent of fibrosis (P = 0.001) and the density of fibroblasts (P = 0.001). There was also a marked difference in nerve root entrapment (P = 0.182) and the presence of sublaminar fibrosis (P = 0.061) between the treatment and control groups. MRI revealed less gadolinium enhancement at the irradiated levels compared with the nonirradiated levels, confirming the usefulness of MRI in predicting the degree of epidural fibrosis. CONCLUSION: Low-dose external beam radiation therapy administered 24 hours before laminectomy in a dog model significantly decreased the extent and density of peridural fibrosis as well as nerve root entrapment and sublaminar fibrosis. This treatment strategy may be efficacious in patients with recurrent radicular pain after lumbar discectomy that is thought to be secondary to peridural fibrosis on the basis of gadolinium-enhanced MRI studies, and who might benefit from reoperation for nerve root decompression.

A formal risk assessment of silicone breast implants.

In 1992, the United States Food and Drug Administration (FDA) announced that breast implants filled with silicone gel would be available only through controlled clinical studies despite the fact that they had been used for mammoplasty in millions of women around the world for more than 30 years. The safety of silicone gel breast implants had come into question after several reports on a possible association between the implants and subsequent development of connective-tissue diseases. Risk assessment refers to the systematic, scientific characterization of potential adverse effects of human exposures to hazardous agents or activities. The following risk assessment is intended to review the current scientific evidence for the safety of silicone gel-filled breast implants since the FDA's decision in 1992. There now appears ample evidence from the scientific literature for the safety of these prostheses.

Inhibition of peridural fibrosis after laminectomy using low-dose external beam radiation in a rat model.

OBJECTIVE: Clinical studies have revealed a significant association between the presence of extensive postlumbar discectomy peridural scar formation and the reoccurrence of low back and radicular pain. Low-dose perioperative radiation therapy has been shown to inhibit scar formation. Its effect on peridural fibrosis, however, has not been studied. METHODS: Thirty male Sprague-Dawley rats underwent L5 laminectomies. Ten rats each received a single fraction of 700-cGy external beam radiation to the lumbar spine 24 hours before surgery; 10 rats each received 700 cGy 24 hours after surgery. The remaining 10 rats served as a control group. All of the rats were killed 30 days after surgery. The spines were harvested, and axial histological sections through the laminectomy defect were evaluated. Each specimen was scored for extent, density, and arachnoidal involvement by fibrosis. RESULTS: There was a statistically significant difference between the treatment and control groups regarding the extent of fibrosis along the dura (P < 0.001), the density of fibroblasts (P < 0.005), and the arachnoid involvement (P < 0.01). There was no difference in fibrosis reduction between the groups receiving pre- and postlaminectomy radiation. CONCLUSION: Low-dose external beam radiation therapy administered before or after laminectomy in a rat model significantly decreases the extent, density, and arachnoidal involvement of peridural fibrosis. This technique may improve the outcome of patients who undergo reoperations for recurrent radicular and/or low back pain after successful lumbar discectomy in whom there is a significant amount of peridural fibrosis.

Silicone breast implants: an oncologic perspective.

In 1992, the FDA decided that silicone gel-filled breast implants would be available only through controlled clinical studies, despite the fact that they had been used for mammoplasty in millions of women around the world for more than 30 years. The safety of silicone breast implants had been called into question after several reports of a possible association between the implants and the subsequent development of connective tissue diseases. Such reports led to general public concern fueled by popular media attention and multiple class-action lawsuits against the product's manufacturers. It was in this climate that the FDA was forced to make its decision. This article reviews current scientific evidence on the safety of silicone gel-filled breast implants. Issues pertinent to oncology are highlighted. These include the possible carcinogenic effect of silicone gel, the safety of irradiating breasts with silicone implants, and the ability to mammographically image the implanted breast.

Outcomes research: a review.

PURPOSE: The purpose of this article is to review the history of the medical outcomes movement as well as the methodologies used in outcomes research. CONCEPT: Outcomes research refers to a genre of clinical investigation that emphasizes the measurement of patient health outcomes, including the patient's symptoms, functional status, quality of life, satisfaction with treatment, and health care costs. RATIONALE: Outcomes research evolved from studies that demonstrated the presence of wide geographic variations in the practice of medicine and surgery. Such differences in utilization were unaccompanied by any discernible difference in patient outcomes. With escalating health care costs, there has been a growing interest in measuring the outcomes of medical intervention to determine the quality and appropriateness of medical care. DISCUSSION: Outcomes may be measured both directly and indirectly, over differing periods of time, and with varying degrees of objectivity, reliability, and validity. Current research has focused on quality of life issues, which include the extent to which a patient's usual or expected physical, emotional, and social well-being have been affected by a medical condition or treatment. The true value of health care can be determined only by a systematic examination of patient outcomes. To accomplish this goal, methods are required that are relatively unfamiliar to many clinical researchers. Future clinical research should include patient-oriented outcome measures that would otherwise focus solely on physiological or anatomic outcomes. Such information will be essential in determining which medical and surgical treatment strategies should be abandoned and which will gain acceptance in the future.

Intraoperative hypothermia and ventricular shunt infections.

Several recent studies have demonstrated a relationship between intraoperative hypothermia and postoperative infection. A study was therefore conducted to evaluate the relationship between intraoperative hypothermia and ventricular shunt infections. Sixty-eight children who underwent ventricular shunt placement, including revisions, over a six year period subsequently developed a shunt infection (overall shunt infection rate of 5%). Mean age was 8 years (range, neonate to 20 years). The last 74 children who underwent ventricular shunt placement without subsequent infection served as a comparison group. The anesthetic records of all cases were reviewed to determine the lowest core temperature recorded during the surgical procedure. The lowest core temperature varied from 33.9 degrees C to 37.7 degrees C (mean 36.0 degrees C). Hypothermia was defined as a temperature less than 35.1 degrees C. No relationship was found between hypothermia and the subsequent occurrence of a shunt infection (P = 0.45). When those children less than 2 years old were excluded from analysis, there was a trend towards statistical significance (P = 0.07). In summary, this study failed to show any significant relationship between the occurrence of intraoperative hypothermia and subsequent ventriculoperitoneal shunt infection in a group of pediatric patients.

Intrathecal baclofen infusion and subsequent orthopedic surgery in patients with spastic cerebral palsy.

UNLABELLED: Intrathecal baclofen infusion (IBI) is an effective treatment for spasticity secondary to cerebral palsy (CP). OBJECT: To assess the need for orthopedic surgery of the lower extremities in such cases, the authors retrospectively reviewed the outcome in 48 patients with spastic CP who were treated with IBI. METHODS: Pumps were placed in 40 patients (84%) suffering from spastic quadriplegia and eight patients (16%) with spastic diplegia. The patients' ages ranged from 5 to 43 years (mean 15 years). The mean follow-up period was 53 months (range 24-94 months). The mean baclofen dosage was 306 microg/day (range 25-1350 microg/day). At the time of pump placement, subsequent orthopedic surgery was planned in 28 patients (58%); however, only 10 (21%) underwent surgery after IBI therapy. In all 10 cases, the surgical procedure was planned at the time of initial evaluation for IBI therapy. In the remaining 18 patients, who did not subsequently undergo their planned orthopedic operation, it was believed that their lower-extremity spasticity had improved to the degree that intervention was no longer indicated. In addition, although six patients had undergone multiple orthopedic operations before their spasticity was treated, no patient required more than one operation after IBI treatment for spasticity. CONCLUSIONS: The authors conclude that IBI for treatment of spastic CP reduces the need for subsequent orthopedic surgery for the effects of lower-extremity spasticity. In patients with spastic CP and lower-extremity contractures, spasticity should be treated before orthopedic procedures are performed.

Diseases of the skull in pre-Columbian South American mummies.

OBJECTIVE: The majority of paleopathological investigations focus on the study of the skull. This is because the skull is the most frequently preserved part of the human body recovered from archaeological excavations. From studying the skull, a variety of information can be obtained regarding the individual, such as sex, age, nutritional status, and other disease processes, if present. METHODS: This study represents the examination of more than 700 human skulls recovered from archaeological excavations from the Andean region of southern Peru and northern Chile and dating back more than 8000 years. RESULTS: A variety of skull abnormalities were encountered. The nonmetric variables of Huschke's foramina and palatine tori were common. Cranial deformation was observed in more than 85% of the cases. There were two cases of sagittal synostosis. Iron deficiency anemia resulting in porotic hyperostosis of the skull was evident in certain cultures. Exostoses of the external auditory canal resulting from chronic otitis was evident only among coastal populations. One skull demonstrated a periostitis consistent with Treponema infection. Trephination was encountered only in the skulls from Peru. Fifty-four cases of skull fractures were observed, half of which showed evidence of healing. Finally, only two cases of neoplastic skull lesions were encountered. CONCLUSION: The study of the human skull alone provides a large amount of information regarding the health and diseases of ancient populations.

Oncology in the era of managed care.

The field of oncology, both with regards to clinical care as well as research, is rapidly changing in response to the current changes in our health care delivery system. Cancer is the second leading cause of death in the United States, exceeded only by heart disease. Cancer care, including screening, diagnosis, treatment, and supportive care, consumes approximately 15% of all health care costs in the United States. The National Cancer Institute estimates the overall costs for cancer at $104 billion per year. Despite the increasing incidence of cancer, federal funding for cancer research has actually declined. Managed care's emphasis on cost reduction is threatening all aspects of the care of patients with cancer. Along these same lines, clinical research support has been dramatically affected by managed care. The major critical issues in the future will be guaranteed access of patients to high-quality cancer care, access to qualified clinical trials, promotion of cancer prevention programs, and support of professional education in oncology. The American Cancer Society estimates that in 1997, 1,382,400 new cases of cancer are expected to be diagnosed in the United States. This year alone, 560,000 Americans are expected to die of cancer. Cancer is the second leading cause of death in the United States, exceeded only by heart disease. One of every four deaths in the United States is due to cancer. The field of oncology, both with regards to clinical care as well as research, is rapidly changing in response to the current changes in our health care delivery system. This paper will address how these changes are having a major impact on the practice of cancer care in the United States.

Primary parafalcine chondrosarcoma in a child.

Intracranial cartilaginous tumors are rare lesions, usually arising from the skull base in older individuals. We report the case of a 12-year-old girl with a low-grade type chondrosarcoma arising from the falx cerebri. To our knowledge this is the first such case reported in a child. She was treated with gross total surgical resection followed by external beam radiation because there was evidence of dural infiltration by tumor in and around the superior sagittal sinus. The patient remains progression free 9 months after surgery.

Intracranial ependymomas of childhood. Lack of correlation of histopathology and clinical outcome.

The histopathology of 66 children with the diagnosis of ependymoma who were operated on at our institution between 1954 and 1994 were reviewed. We performed an initial analysis using the entire study cohort to determine which histopathological features associated with each other in a statistically significant fashion in an attempt to identify combinations of features that together might be useful in predicting outcome. A detailed outcome analysis was then performed on the 37 most recent cases who survived the postoperative period, in whom pre- and post-imaging studies as well as long term follow-up were obtained, in order to identify the histopathological features and combinations of features that were predictive of overall and progression-free survival. Five- and ten-year progression-free survivals were 45.1% and 36.1%, respectively. Overall survivals were 57.1% and 45.0%, respectively. Of the eight individual histopathological features, only the presence of necrosis was found to correlate with a less favorable overall and progression-free survival (PFS) (p = 0.06 and 0.03, respectively). In addition, the combination of necrosis with vascular proliferation or nuclear pleomorphism was associated with a worse PFS (p = 0.01 and 0.02, respectively). However, when other clinical predictive factors were included in a multivariate regression analysis, none of the histological features or combinations of features were independently associated with outcome. In addition, no relationship was found between the pattern of rosettes (true rosette, pseudorosette, or perivascular pseudorosette) and clinical outcome. In conclusion, although this study found an association between certain histopathological features and clinical outcome in children with ependymomas, these relationships did not reach statistical significance on multivariate analysis and, thus, do not provide sufficient evidence for modifying therapy based on histopathology alone.

Seizure outcome in children treated for arteriovenous malformations using gamma knife radiosurgery.

Seizures are the second most common presenting symptom of arteriovenous malformations (AVMs) in children. Although radiosurgery has been found to be a safe and effective alternative treatment, the outcome of seizure control in children after radiosurgery for AVMs is unknown. Between 1987 and 1994, 72 children under the age of 18 years were treated with gamma knife radiosurgery for AVMs at our institution. Fifteen patients (21%) had seizures as part of their clinical course. There were 11 boys and 4 girls with ages varying from 2 to 17 years (median 16 years). Seizures included: generalized tonic-clonic (n = 8); focal motor or sensory (n = 4); partial complex (n = 2), and a combination of generalized and partial complex (n = 1). Nine lesions were in cortical locations; six were subcortical. Spetzler-Martin grades included: II (n = 7); III (n = 4); IV (n = 2), and VI (n = 2). During follow-up after radiosurgical treatment, 11 of 13 patients (85%) were seizure free and off anticonvulsant therapy (mean follow-up 47 months). Two patients had a significant improvement in their seizures but continue on medication. Two of the 72 patients (3%) developed seizures after treatment and remain on medication. Seizure outcome was not associated with the location or complete obliteration of the lesion. We conclude that stereotactic radiosurgery, as a non-invasive alternative, is associated with a good outcome for the AVM as well as AVM-related seizures in children.

Intracranial ependymomas of childhood: long-term outcome and prognostic factors.

A detailed outcome analysis was performed on 40 children with intracranial ependymomas treated at our institution between 1975 and 1993 to identify those factors that were predictive of overall and progression-free survival. Three patients (7.5%) who were treated in the first 5 years of the study died within 3 months of surgery and were excluded from further outcome assessments. Eight (22%) of the 37 patients who survived the perioperative period had evidence of leptomeningeal dissemination at presentation, on the basis of either imaging (three children) and/or cytological (six children) results. The 5- and 10-year progression-free survival rates among these 37 patients were 45.1 and 36.1%, respectively; overall survival rates were 57.1 and 45.0%, respectively. The site of progression was local in 17 of 19 patients with progressive disease. Three factors were found to have a significant association (P < or = 0.05) with the outcome on both univariate and multivariate analyses: 1) the extent of the resection, 2) the age of the patient at diagnosis, and 3) the duration of the symptoms before diagnosis. The 5-year progression-free and overall survivals were 8.9 and 22%, respectively, among patients who had evidence of residual disease on postoperative imaging studies, compared with 68 and 80% rates among patients with no apparent residual disease (P = 0.0001 and P < 0.0001, respectively). Patients younger than 3 years fared significantly worse than older children (5-year progression-free and overall survival rates of 12 and 22%, respectively, in the younger children versus 60 and 75% in older children (P = 0.003 and P = 0.01, respectively). In addition, patients with a duration of symptoms before diagnosis of < 1 month had a worse outcome than those with a more protracted course (5-year progression-free and overall survival rates of 33 and 33%, respectively, versus rates of 53 and 64%, respectively (P = 0.02 for both). Neither the finding of evidence for dissemination at presentation nor the detection of anaplastic histological features (e.g., dense cellularity or high numbers of mitoses) were associated with a significantly worse outcome in this series. The combination of variables that had the strongest association with both favorable and unfavorable outcomes was the combination of the age of the patient and the resection extent. Only 2 of 17 patients older than 3 years with gross total resections have died, whereas 13 of 20 children who were either younger than 3 years or had radiologically incomplete resections have died (P < 0.0001).(ABSTRACT TRUNCATED AT 400 WORDS)

Single-stage stereotactic diagnosis and radiosurgery: feasibility and cost implications.

We compared the efficacy and the hospital charges of either single-stage or two-stage stereotactic diagnosis and radiosurgery procedures. Twelve patients underwent either one-stage or two-stage diagnosis and management of their brain tumors. Both techniques utilize high-resolution intraoperative stereotactic image-guided technology and rapid touch preparation (imprint) cytopathological techniques to confirm the presence of neoplasm. Following this pathologic diagnosis, six patients immediately underwent stereotactic radiosurgery employing the same frame application and dose planning based on preoperative and intraoperative images. Six patients underwent two-stage procedures, i.e., discharge from the hospital after histopathological diagnosis followed by readmission, reapplication of the stereotactic head frame, and repeat neuroradiological imaging prior to radiosurgery. Requirements for success of the single-stage procedure include intraoperative stereotactic high-resolution imaging, a hospital-wide ethernet system for transferring neurodiagnostic images, and expertise in rapid touch-preparation histopathological technique for accurate diagnosis. Intraoperative computed tomography imaging after biopsy confirmed the target accuracy and lack of movement of the target after brain biopsy. The advantages of the single-stage approach include reduced length of overall hospital stay, simultaneous histopathological diagnosis and therapy in a single hospital admission, and reduced total hospital charges. For patients highly suspected of having brain tumors and for whom stereotactic radiosurgery will be utilized in the treatment, single-stage stereotactic diagnosis immediately followed by radiosurgery is an accurate, effective, and potentially less costly management strategy than a two-stage approach.

Relationship between cerebellar appearance and function in children with Dandy-Walker syndrome.

In children with Dandy-Walker syndrome (DWS), the relationship between cerebellar appearance on imaging and either cerebellar function or intellect is unknown. To evaluate those relationships, we retrospectively studied 20 patients with DWS treated in our institution between 1978 and 1994. The patients were treated with ventriculoperitoneal, cystoperitoneal, or ventriculocystoperitoneal shunts. Intellectual and cerebellar function were determined from neurological and developmental testing. Cerebellar development was evaluated by measuring cerebellar and posterior fossa volumes from computed tomography images; the ratio of cerebellar size to posterior fossa size was considered to reflect cerebellar development. The cerebellar function was normal in 50% and the intellectual function in 45% of the patients. There was no correlation between cerebellar size and intellectual development or cerebellar function. There was also no correlation between the type of shunt and the subsequent cerebellar size. We conclude that there is no relationship between the cerebellar development evident on computed tomography scans and the cerebellar or the intellectual function of children with DWS. We, therefore, infer that treatment of Dandy-Walker cysts with posterior fossa shunts is unlikely to enhance the cerebellar function.