Mechanical Complications of Sophysa SM8 Shunt in Adult Hydrocephalus: A Monocentric Experience.

BACKGROUND: Sophysa SM8 is widely used by neurosurgeons in France. Published studies report shunt malfunction rates in adults between 18% and 29%. However, these studies included multiple valve types and thus entailed a serious confounding factor. OBJECTIVE: To ascertain the incidence the Sophysa SM8 cerebrospinal fluid (CSF) shunt malfunctions in adults. METHODS: We present a retrospective series of adult patients who underwent CSF shunt placement between 2000 and 2013 with Sophysa SM8. RESULTS: In total, 599 patients (329 males and 270 females) were included. The mean age at surgery was 64.15 years (19-90) (SD 16.17; median 68.0). The causes of hydrocephalus were normal pressure hydrocephalus (49%), traumatic hemorrhages (26.5%), tumors (15.7%), cerebral aqueduct stenoses (3%), and arachnoid cysts (2%). The mean follow-up was 3.9 years (0-16) (SD 4.10; median 3 years). The rate of complications was 22.04% (132 of 599). Most frequent causes of complications were disconnection (25%), migration (12.9%), overdrainage (9.1%), and proximal obstruction (6.8%). In 17 cases (12.9%), no failure was diagnosed during revision. Seven infections (5.3%) were reported. The mean delay for the first revision was 1.70 years (0-13.93) (SD 2.67, median 0.35). The risk of shunt failure was 36% at 10 years. Seventeen percent of revisions occurred during the first year after shunt placement. CONCLUSION: Disconnections are a very frequent complication of Sophysa SM8 valve. They are related to the 2-connector system of this valve. Based on these results, we recommend using 1-piece valves.

Mechanical complications of cerebrospinal fluid shunt. Differences between adult and pediatric populations: myths or reality?

OBJECTIVE: Shunt malfunctions seem more frequent in children (44 to 81%) than in adults (18 to 29%). Because of discrepancies between studies, it is not possible to affirm this disparity. The objective was to verify whether the incidence of cerebrospinal fluid (CSF) shunt malfunctions is higher in children than adults. METHODS: We present a retrospective series of child and adult patients who underwent CSF shunt placement between 2000 and 2013 with a Sophysa SM8® valve. RESULTS: 599 adults and 98 children (sex ratio 1.28) underwent CSF shunt placement. Age at first surgery ranged between 1 day of life and 90 years (mean of 55.8 years, SD 25.8, median 64.8 years). The mean follow-up was 4 years (SD 4.264, 0-16; median 3 years). The cumulative complication rate was 25.5% (178/697). Mechanical complications were disconnection (25.1%), migration (11.8%), intracranial catheter obstruction (8.9%) and malposition (8.4%). The mean delay for the first revision was 1.90 years (0-13.9), (SD 2.73, median 0.5). The probability of shunt failure was 65% at 10 years in the child group and 36% at 10 years in the adult group. Moreover, in the child group, 33% of revisions occurred during the first year after shunt placement versus 17% in the adult group. Thus, the probability of shunt failure was higher in children than in adults (log-rank test, p < 0.001). CONCLUSIONS: This is the first retrospective study, comparing children and adults undergoing CSF shunt using the same valve, able to confirm the higher rate of complications in children.

Utility of S100B Serum Level for the Determination of Concussion in Male Rugby Players.

BACKGROUND: The incidence of concussion in professional direct-contact sports, particularly in rugby, has increased in recent years. To date, cognitive assessment is the most common means of determining whether a concussed player can return to the game. Serum S100B assay, an objective blood test known to be useful in brain injury management, may offer a novel additional approach to the management of concussed male rugby players. OBJECTIVE: The aim of this study was to investigate the S100B utility for the determination of concussion in a professional 15-players-a-side rugby team. METHODS: Thirty-nine male rugby players were included in a prospective study during the 2014-2015 French championship season. Serum sampling was carried out several times at baseline and after a match and/or a concussion, at set times (2, 36 h). Serum S100B concentrations were determined using chemiluminescence immunoassay on a Roche Diagnostics® instrument. RESULTS: The players' basal serum S100B was stable during the season and was not correlated with anthropometric data, body composition, or creatine kinase concentration. A significant increase in S100B concentration within 2 h after a game (without concussion) was observed. This increase was correlated with the number of body collisions during a match. Seventy-seven assays were performed 36 h after a game, including the follow-up of five concussed players. Thirty-six hours after a match, an increase of a minimum of 20 % compared with individual basal concentrations identified concussion with 100 % sensitivity and 81 % specificity. CONCLUSION: S100B measured 36 h after a match is thus a discriminating test to identify concussion in a male rugby player, with a 100 % negative predictive value.

Validation of a noninvasive test routinely used in otology for the diagnosis of cerebrospinal fluid shunt malfunction in patients with normal pressure hydrocephalus.

OBJECTIVE: Ventriculoperitoneal shunting is the first-line treatment for normal pressure hydrocephalus. Noninvasive auditory tests based on recorded otoacoustic emissions were assessed, as currently used for universal neonatal hearing screenings, for the diagnosis of cerebrospinal fluid shunt malfunction. The test was designed based on previous works, which demonstrated that an intracranial pressure change induces a proportional, characteristic, otoacoustic-emission phase shift. METHODS: Forty-four patients with normal pressure hydrocephalus (23 idiopathic and 21 secondary cases) were included in this prospective observational study. The male:female sex ratio was 1.44, the age range was 21-87 years (mean age 64.3 years), and the range of the follow-up period was 1-3 years (mean 20 months). Patients were implanted with a Sophy SU8 adjustable-pressure valve as the ventriculoperitoneal shunt. The phase shifts of otoacoustic emissions in response to body tilt were measured preoperatively, immediately postoperatively, and at 3-6 months, 7-15 months, 16-24 months, and more than 24 months postoperatively. Three groups were enrolled: Group 1, 19 patients who required no valve opening-pressure adjustment; Group 2, 18 patients who required valve opening-pressure adjustments; and Group 3, 7 patients who required valve replacement. RESULTS: In Group 1, phase shift, which was positive before surgery, became steadily negative after surgery and during the follow-up. In Group 2, phase shift, which was positive before surgery, became negative immediately after surgery and increasingly negative after a decrease in the valve-opening pressure. In Group 3, phase shift was positive in 6 cases and slightly negative in 1 case before revision, but after revision phase shift became significantly negative in all cases. CONCLUSIONS: Otoacoustic emissions noninvasively reflect cerebrospinal fluid shunt function and are impacted by valve-opening pressure adjustments. Otoacoustic emissions consistently diagnosed shunt malfunction and predicted the need for surgical revision. The authors' diagnostic test, which can be repeated without risk or discomfort by an unskilled operator, may address the crucial need of detecting valve dysfunction in patients with poor clinical outcome after shunt surgery.

SCO-spondin derived peptide NX210 induces neuroprotection in vitro and promotes fiber regrowth and functional recovery after spinal cord injury.

In mammals, the limited regenerating potential of the central nervous system (CNS) in adults contrasts with the plasticity of the embryonic and perinatal periods. SCO (subcommissural organ)-spondin is a protein secreted early by the developing central nervous system, potentially involved in the development of commissural fibers. SCO-spondin stimulates neuronal differentiation and neurite growth in vitro. NX210 oligopeptide was designed from SCO-spondin's specific thrombospondin type 1 repeat (TSR) sequences that support the main neurogenic properties of the molecule. The objective of this work was to assess the neuroprotective and neuroregenerative properties of NX210 in vitro and in vivo for the treatment of spinal cord injury (SCI). In vitro studies were carried out on the B104 neuroblastoma cell line demonstrating neuroprotection by the resistance to oxidative damage using hydrogen peroxide and the measure of cell viability by metabolic activity. In vivo studies were performed in two rat models of SCI: (1) a model of aspiration of dorsal funiculi followed by the insertion of a collagen tube in situ to limit collateral sprouting; white matter regeneration was assessed using neurofilament immunostaining; (2) a rat spinal cord contusion model to assess functional recovery using BBB scale and reflex testing. We demonstrate for the first time that NX210 (a) provides neuroprotection to oxidative stress in the B104 neuroblastoma cells, (b) stimulates axonal regrowth in longitudinally oriented neofibers in the aspiration model of SCI and (c) significantly improves functional recovery in the contusive model of SCI.

Vasospasm of labyrinthine artery in cerebellopontine angle surgery: evidence brought by distortion-product otoacoustic emissions.

In cerebellopontine angle (CPA) surgery, postoperative deafness can be due to alteration of cochlear blood flow that is supplied by the labyrinthine artery (LA). In particular, vasospasm is likely to occur and, if so, can be reversed. This work attempted to track down vascular events occurring during CPA surgery. Twenty consecutive patients with vestibular schwannoma were tested with useful preoperative hearing and presence of otoacoustic emissions (OAEs). Distortion-product otoacoustic emissions (DPOAEs), well-known to react within seconds to cochlear ischemia, were used intraoperatively to indirectly monitor cochlear blood flow. Continuous intraoperative monitoring of DPOAEs revealed three different time patterns associated with distinct auditory outcomes. Pattern P1-acute (n = 4) happened when the LA was severed: DPOAEs immediately and irreversibly foundered and led to postoperative deafness. Pattern P2-protracted (n = 7) revealed a progressive deterioration of DPOAEs from the beginning of tumor debulking, likely due to a steady decrease of cochlear blood flow, with postoperative deafness. Pattern P3-unstable (n = 5) corresponded to large DPOAE oscillations between their normal level and noise floor. It was due to acute LA vasospasm that could be reversed in three cases by topical nimodipin. Last, four patients had uneventful cochlear monitoring. In conclusion, cochlear ischemia can occur in vestibular schwannoma surgery, giving three different patterns among which vasospasm can be reversed if detected early.

Aggressive silent GH pituitary tumor resistant to multiple treatments, including temozolomide.

Temozolomide (TMZ) has been proposed as a therapeutic option in aggressive pituitary tumors. Among the published cases, GH expressing tumors were rare. We describe a patient with initially benign silent GH adenoma that transformed into an aggressive GH secreting tumor resistant to usual therapy. MGMT expression was high and the MGMT promoter was unmethylated. Before this aggressive course, patient received three cycles of TMZ; no response was observed. Four cases of GH aggressive tumor treated by TMZ have been reported. Response to TMZ was observed in one of these four patients. Predictive factors of failure of TMZ remain unclear.

MRI tumor response and clinical outcomes after LINAC radiosurgery on 50 patients with recurrent malignant gliomas.

BACKGROUND: The place of radiosurgery (RS) as an option in the treatment of recurrent malignant glioma is still debated on in the absence of prospective randomized trials. OBJECTIVE: To assess the clinical outcome and MRI response after radiosurgery of recurrent malignant glioma. METHODS: We evaluated 50 consecutive patients treated in a single institution. Between 2001 and 2008, 34 glioblastoma (GBM) and 16 anaplastic oligodendroglioma (AO) patients were treated with linear accelerator (Linac) RS for recurrence. RESULTS: The median marginal dose was 15 Gy and the median gross tumor volume (GTV) was 6.64 ml. No patient had acute (< 3 months) neurological morbidity after RS. Ten patients (20%) were reoperated on after RS, histopathological findings included necrosis alone in 3 cases (6%). The median overall survival was 21.5 months for GBM and 57.9 months for AO. The median survival after RS was 9.5 months for GBM and 32.9 months for AO. The median progression-free survival after RS was 6.7 months for GBM and 18 months for AO. MRI volume modifications after RS showed a transitory reduction or stabilization of disease linked to significantly improved survival in 58.8% of patients with GBM, 81.1% of patients with AO. Pathological subtype (AO versus GBM), MRI response, KPS >70, marginal dose > 13 Gy, largest diameter of GTV < 25 mm and GTV < 7 ml were the main prognostic factors, associated with improved survival or PFS from RS. CONCLUSION: The magnitude of the survival increase compared to historical RPA classes may not be due to selection bias alone. Linac RS in selected patients with recurrent malignant glioma was well tolerated, effective and can be considered as one of several re-treatment options.

Electrophysiological monitoring of cochlear function as a non-invasive method to assess intracranial pressure variations.

The "cochlear" aqueduct is a narrow channel connecting the subarachnoid and intralabyrinthine spaces. Through this communication, cerebrospinal fluid (CSF) pressure variations are transmitted to the intralabyrinthine space and modify the impedance of the ear. Distortion-product otoacoustic emissions (DPOAE) are sounds emitted by cochlear sensory cells in response to sonic stimulation. Cochlear microphonic potentials (CMP) express the electrophysiological activity of cochlear sensory cells. At 1 kHz, the phase of DPOAE and CMP varies according to the impedance of the ear and thus to intracranial pressure (ICP) variations. DPOAE and CMP have been shown to strictly follow ICP variations produced during infusion tests performed in the diagnosis of chronic hydrocephalus. DPOAE and CMP recordings appear to be valuable tools for monitoring ICP non-invasively.

Brain mapping in stereotactic surgery: a brief overview from the probabilistic targeting to the patient-based anatomic mapping.

In this article, we briefly review the concept of brain mapping in stereotactic surgery taking into account recent advances in stereotactic imaging. The gold standard continues to rely on probabilistic and indirect targeting, relative to a stereotactic reference, i.e., mostly the anterior (AC) and the posterior (PC) commissures. The theoretical position of a target defined on an atlas is transposed into the stereotactic space of a patient's brain; final positioning depends on electrophysiological analysis. The method is also used to analyze final electrode or lesion position for a patient or group of patients, by projection on an atlas. Limitations are precision of definition of the AC-PC line, probabilistic location and reliability of the electrophysiological guidance. Advances in MR imaging, as from 1.5-T machines, make stereotactic references no longer mandatory and allow an anatomic mapping based on an individual patient's brain. Direct targeting is enabled by high-quality images, an advanced anatomic knowledge and dedicated surgical software. Labeling associated with manual segmentation can help for the position analysis along non-conventional, interpolated planes. Analysis of final electrode or lesion position, for a patient or group of patients, could benefit from the concept of membership, the attribution of a weighted membership degree to a contact or a structure according to its level of involvement. In the future, more powerful MRI machines, diffusion tensor imaging, tractography and computational modeling will further the understanding of anatomy and deep brain stimulation effects.