Hangman's fracture in an osteogenesis imperfecta patient.

BACKGROUND: Traumatic spondylolisthesis of the axis, also known as a hangman's fracture, is a well-described entity but is relatively uncommon. There are only two published reports of these fractures occurring in pediatric patients with osteogenesis imperfecta, a disorder that predisposes patients to long bone fractures. CASE DESCRIPTION: We present a unique case of an adult woman with osteogenesis imperfecta who sustained an Effendi type II hangman's fracture. CONCLUSION: Effendi type II fractures can be conservatively managed via rigid or nonrigid cervical orthosis.

Congenital hydrocephalus and ventriculoperitoneal shunts: influence of etiology and programmable shunts on revisions.

OBJECT: Hydrocephalus is a notorious neurosurgical disease that carries the adage "once a shunt always a shunt." This study was conducted to review the treatment results of pediatric hydrocephalus. METHODS: Pediatric patients who underwent ventriculoperitoneal shunt surgery over the past 14 years were reviewed for shunt revisions. Variables studied included age at shunt placement, revision, or replacement; programmable shunts; infection; obstruction; and diagnosis (congenital, posthemorrhagic, craniospinal dysraphism, and others including trauma, tumors, and infection). Multiple regression analysis methods were used to determine independent risk factors for shunt failure and the number of shunt revisions. The Kaplan-Meier method of survival analysis was used to compare etiologies on the 5-year survival (revision-free) rate and the median 5-year survival time. RESULTS: A total of 253 patients were studied with an almost equal sex distribution. There were 92 patients with congenital hydrocephalus, 69 with posthemorrhagic hydrocephalus, 48 with craniospinal dysraphism, and 44 with other causes. Programmable shunts were used in 73 patients (other types of shunts were used in 180 patients). A total of 197 patients (78%) underwent revision surgeries due to shunt failures. The mortality rate was 1.6%. Age at first revision, the 5-year survival rate, and the median 5-year survival time were significantly less for both posthemorrhagic and craniospinal dysraphism than for either the congenital or "other" group (p < 0.05). The failure rate and number of revisions were not significantly reduced with programmable shunts compared with either pressure-controlled or no-valve shunts (p > 0.5). CONCLUSIONS: Posthemorrhagic hydrocephalus and craniospinal dysraphism hydrocephalus had significantly earlier revisions than congenital and other etiologies. Programmable systems did not reduce the failure rate or the average number of shunts revisions.

Traumatic spondylolisthesis of the axis: a biomechanical comparison of clinically relevant anterior and posterior fusion techniques.

OBJECT: Surgical management of unstable traumatic spondylolisthesis of the axis includes both posterior and anterior fusion methods. The authors performed a biomechanical study to evaluate the relative stability of anterior fixation at C2-3 and posterior fixation of C-1 through C-3 in hangman's fractures. METHODS: Fresh-frozen cadaveric spine specimens (occipital level to T-2) were subjected to stepwise destabilization of the C1-2 complex, replicating a Type II hangman's fracture. Intact specimens, fractured specimens, and fractured specimens with either anterior screw and plate or posterior screw and rod fixation were each tested for stability. Each spine was subjected to separate right and left rotation, bending, flexion, and extension testing. RESULTS: Anterior fixation restored stiffness in flexion and extension movements to values greater than those for intact specimens. For other movement parameters, the values approximated those for intact specimens. Posterior fixation increased the stiffness to above those values seen for anterior fixation specimens. CONCLUSIONS: In cadaveric spine specimens subjected to a Type II hangman's fracture, both anterior fixation at C2-3 and posterior fixation with C-1 lateral mass screws and C-2 and C-3 pedicle screws resulted in a consistent increase in stiffness, and hence in stability, over intact specimens.

Ventriculosubgaleal shunts for posthemorrhagic hydrocephalus in premature infants.

OBJECTIVE: The early management of posthemorrhagic hydrocephalus in premature infants is challenging and controversial. These infants need a temporary cerebrospinal fluid (CSF) diversion procedure until they gain adequate weight, and the blood and protein levels in CSF are reasonably low before permanent shunt can be placed. Various options are available with their associated advantages and disadvantages. Ventriculosubgaleal shunts have been recommended as a more physiologic and less invasive means of achieving this goal. We have performed this procedure in 6 premature infants to evaluate their effectiveness and complications. METHODS: Six consecutive premature infants with posthemorrhagic hydrocephalus underwent placement of ventriculosubgaleal shunts over a 1-year period of time. We reviewed their clinical and imaging progress to assess the ability of the shunt to control hydrocephalus and the complication rates. RESULTS: In all 6 patients, the ventriculosubgaleal shunt controlled the progression of hydrocephalus as assessed by clinical and imaging parameters. A permanent shunt was avoided in 1 patient (16.6%). However, 4 patients developed shunt infections, 1 involving the ventriculosubgaleal shunt itself, and 3 immediately after conversion to ventriculoperitoneal shunt. The total infection rate of the series was 66.6%. All infections were caused by staphylococcus species. There was only a 1% shunt infection rate in our institution for all nonventriculosubgaleal shunts during the same period of time. CONCLUSION: Placement of ventriculosubgaleal shunts for interim CSF diversion in neonates with posthemorrhagic hydrocephalus is effective as a temporary method of CSF diversion. However, our experience has shown that it is associated with a unacceptably high CSF infection rate. A potential cause for infection is CSF stasis just beneath the extremely thin skin of the premature infants, promoting colonization by skin flora. CSF sampling before conversion to a permanent shunt and replacement of the proximal hardware, which has been in situ for a prolonged period, may decrease the infection rates. At present, the procedure is no longer performed at our institution.