Stented endoscopic third ventriculostomy: technique, safety, and indications-a multicenter multinational study.

PURPOSE: Endoscopic third ventriculostomy (ETV) is an effective treatment for obstructive hydrocephalus. Secondary stoma closure may be life threatening and is the most common reason for late ETV failure, mostly secondary to local scarring. Local stents intended to maintain patency are rarely used. In this study, we summarize our experience using stented ETV (sETV), efficacy, and safety. MATERIAL AND METHODS: Data was retrospectively collected from all consecutive patients who underwent ETV with stenting at four centers. Collected data included indications for using sETV, hydrocephalic history, surgical technique, outcomes, and complications. RESULTS: Sixty-seven cases were included. Forty had a primary sETV, and 27 had a secondary sETV (following a prior shunt, ETV, or both). The average age during surgery was 22 years. Main indications for sETV included an adjacent tumor (n = 15), thick or redundant tuber cinereum (n = 24), and prior ETV failure (n = 16). Fifty-nine patients (88%) had a successful sETV. Eight patients failed 11 ± 8 months following surgery. Reasons for failure included obstruction of the stent, reabsorption insufficiency, and CSF leak (n = 2 each), and massive hygroma and tumor spread (n = 1 each). Complications included subdural hygroma (n = 4), CSF leak (n = 2), and stent malposition (n = 1). There were no complications associated with two stent removals. CONCLUSION: Stented ETV appears to be feasible and safe. It may be indicated in selected cases such as patients with prior ETV failure, or as a primary treatment in cases with anatomical alterations caused by tumors or thickened tuber cinereum. Future investigations are needed to further elucidate its role in non-communicating hydrocephalus.

Enhancing the Conductivity and Thermoelectric Performance of Semicrystalline Conducting Polymers through Controlled Tie Chain Incorporation.

Conjugated polymers are promising materials for thermoelectric applications, however, at present few effective and well-understood strategies exist to further advance their thermoelectric performance. Here a new model system is reported for a better understanding of the key factors governing their thermoelectric properties: aligned, ribbon-phase poly[2,5-bis(3-dodecylthiophen-2-yl)thieno[3,2-b]thiophene] (PBTTT) doped by ion-exchange doping. Using a range of microstructural and spectroscopic methods, the effect of controlled incorporation of tie-chains between the crystalline domains is studied through blending of high and low molecular weight chains. The tie chains provide efficient transport pathways between crystalline domains and lead to significantly enhanced electrical conductivity of 4810 S cm-1, which is not accompanied by a reduction in Seebeck coefficient or a large increase in thermal conductivity. Respectable power factors of 173 µW m-1 K-2 are demonstrated in this model system. The approach is generally applicable to a wide range of semicrystalline conjugated polymers and could provide an effective pathway for further enhancing their thermoelectric properties and overcome traditional trade-offs in optimization of thermoelectric performance.

Osteoplastic decompressive craniotomy--an alternative to decompressive craniectomy.

BACKGROUND: In spite of various degrees of brain expansion, decompressive surgery is usually carried out using decompressive craniectomy (DC). After craniectomy it is necessary to perform cranioplasty, which prolongs hospitalization and is not always without complications. Hence, in situations when cranial decompression is indicated, but DC would be too radical, we do not remove the bone flap, and we perform so-called osteoplastic decompressive craniotomy (ODC). The technique is detailed. OBJECTIVE: To demonstrate the effectiveness of ODC. METHODS: Twenty patients underwent ODC for brain edema under various pathological conditions. The diagnoses were as follows: 13 subdural hematomas, 3 cerebral contusions, 2 middle cerebral artery infarcts, 1 epidural hematoma and 1 arteriovenous malformation. The effect of ODC was assessed using postoperative ICP monitoring and the midline shift on CT. The ICP threshold for the additional removal of the bone flap was 25 mmHg. Clinical outcome was evaluated 6 months after surgery using the Glasgow Outcome Scale (GOS). RESULTS: Postoperative ICP was up to 25 mmHg in 18 patients and exceeded 25 mmHg in 2 cases. The mean midline shift on CT was 10 mm preoperatively and 3 mm postoperatively. The decompression during ODC was sufficient in 18 patients and insufficient in 2 in whom an additional removal of the bone flap was performed. Eight survivals had a favorable outcome (GOS 4-5); 12 patients had an unfavorable outcome (GOS 1-3), and of these, 4 died. CONCLUSION: Our limited study shows that ODC is effective in the treatment of intracranial hypertension in the selected subgroup of patients in whom DC would be too radical. The main advantage of this method is the elimination of further cranioplasty.

Symptomatic cysts of the cavum septi pellucidi, cavum vergae and cavum veli interpositi: A retrospective duocentric study of 10 patients.

OBJECTIVE: Cysts of the Cavum septi pellucidi (CSP), cavum vergae (CV) and cavum veli interpositi (CVI) are anterior midline intracranial findings which are typically incidental - only rarely do we encounter symptomatic cysts of this type. Only a quite small number of these cysts series have been published, controversies regarding optimal management still exist. PATIENTS AND METHODS: This is a retrospective study of 10 patients treated at 2 clinics between 2002-2018. 9 patients underwent surgery and 1 is under long-term monitoring. Apart from demographic data, the study analyzed symptoms, cyst size and progression over time, ventricle size, complications, and treatment modality. RESULTS: CSP with CV was found in 8 cases with 1 case each of CSP and CVI. The study comprised 6 men and 4 women, including 4 children. The mean follow-up time was 43.4 months. The average cyst size was 20.4 mm in CSP and 19.8 mm in CV; the CVI was 33 mm. Headache was most commonly reported (70%) followed by behavioral disturbance (30%). Disturbance in memory, psychomotor development, school performance, visual acuity, and vomiting was variously noted in 20%. The prevailing symptom was headache in adults and behavioral and autonomic disturbance in children. Postoperatively, cysts had reduced by an average of 44.3% while the ventricles remained unchanged. Symptoms resolved in all cases with residual problems in patients presenting with memory loss. No complications were noted. CONCLUSION: Endoscopic fenestration is the method of choice in the treatment of symptomatic midline cysts. We recommend that any further research focuses on precisely establishing their clinical presentation, particularly neuropsychological symptoms.