Plasmonic titanium nitride nanomaterials prepared by physical vapor deposition methods.

Titanium nitride (TiN) has recently emerged as an alternative to coinage metals to enable the development of integrated plasmonic devices at visible and medium-infrared wavelengths. In this regard, its optical performance can be conveniently tuned by tailoring the process parameters of physical vapor deposition methods, such as magnetron sputtering and pulsed laser deposition (PLD). This review first introduces the fundamental features of TiN and a description on its optical properties, including insights on the main experimental techniques to measure them. Afterwards, magnetron sputtering and PLD are selected as fabrication techniques for TiN nanomaterials. The fundamental mechanistic aspects of both techniques are discussed in parallel with selected case studies from the recent literature, which elucidate the critical advantages of such techniques to engineer the nanostructure and the plasmonic performance of TiN.

Balloon-Assisted Corpus Callosotomy. Reducing the Impact of Transcallosal Approaches.

BACKGROUND: The interhemispheric transcallosal approach is widely used to remove intraventricular lesions. Corpus callosotomy gives immediate access to the ventricular chambers but is invasive in nature. Loss of callosal fibers, although normally tolerate, may cause disturbances ranging from a classical disconnection syndrome up to minor neuropsychological changes. OBJECTIVE: To open an operative window in the corpus callosum through separation rather than disconnection of the white matter fibers. METHODS: In 7 patients undergoing the interhemispheric transcallosal approach for intraventricular lesions, lying around or below the foramen of Monro, a stoma was created within the corpus callosum by using a 4F Fogarty catheter. The series included 3 colloid of the third ventricle, 2 thalamic cavernomas, 1 subependymoma, and 1 ependymoma of the foramen of Monro. We illustrate the technique and the clinico-radiological outcome, focusing on the size of callosotomy as seen on postoperative MRI. RESULTS: The balloon-assisted corpus callosotomy provided a circular, smooth-walled access to the ventricular chambers, which allowed uncomplicated removal of the lesions. On postoperative MRI, the size of the callosotomy shrinked compared with surgery (2.8-6.4 mm at follow-up vs 6-9 mm as measured intraoperatively). No signs of disconnection syndrome or new permanent deficits were observed in this series. CONCLUSION: The balloon-assisted technique produces a small callosotomy, without clinical consequences, showing a self-closing trend on postoperative MRI. This technique is a rewarding tool to reduce the impact of callosotomy while keeping the advantages of microsurgical interhemispheric approaches.

Interhemispheric contralateral approach: the falx as a retractor.

The contralateral transfalcine approach is a valuable option to access lesions around the mesial surface of the brain hemispheres. Despite a favourable perspective, surgical manoeuvres within the interhemispheric fissure carry a risk of inadvertent injury to the healthy cortex on the craniotomy side. To overcome this drawback, a new method of brain retraction was developed. After dissecting the interhemispheric fissure, the falx was incised in an upside-down U-shaped manner and hinged inferiorly, taking care not to violate the inferior sagittal sinus. The falcine flap was reflected laterally and fixed to the lateral edge of the craniotomy, providing homogeneous retraction of the ipsilateral mesial cortex. Surgery proceeded with the brain surface hidden from the surgeon's view and protected by the flap. The absence of retractor devices hindering the surgeon's movements further simplified the procedure.

Antegrade Subperiosteal Temporalis Muscle Elevation and Posterior Retraction Technique Avoiding Muscle Incision for Pterional Craniotomy: A Technical Note.

Background: The current technique of pterional craniotomy involves temporalis muscle incision followed by retrograde elevation. Feasibility of antegrade temporalis muscle elevation without any direct incision over its bulk is evaluated. Objective: Incisionless "antegrade, subgaleal, subfascial, and subperiosteal elevation" of temporalis muscle preserves vascularity and muscle bulk. Posterior maneuvering of "bare" temporalis muscle bulk either above (out rolling) or under (in rolling) the scalp for pterional craniotomy is discussed. Material and Methods: Technique of antegrade, subfascial, subperiosteal elevation, and posterior rotation of temporalis muscle without incising in its bulk by "out rolling" or "in rolling" along the posterior aspect of the scalp incision was carried out in 15 cadavers and later in 50 surgical cases undergoing pterional craniotomy. Postoperatively, patients were evaluated for subgaleal collection and periorbital edema. Operated side cosmesis and temporalis muscle bulk was compared with nonoperated temporalis muscle at 6 months interval. Results: Antegrade subperiosteal dissection of temporalis muscle was possible in all cases. "In-rolling" or "out rolling" technique provided adequate surgical exposure during pterional craniotomy. Postoperative subgaleal collection and periorbital edema was prevented. Facial nerve paresis or temporalis muscle-related complications were avoided. Conclusion: Antegrade, subgaleal, subfascial, and subperiosteal dissection techniques of temporalis muscle elevation without any direct incision in its bulk enables neurovascular and muscle volume preservation. Posterior maneuvering of elevated temporalis muscle with "out rolling" or "in-rolling" technique is easy, quick, and provides adequate exposure during pterional craniotomy. Opening and closing of scalp layers without violating subgaleal space prevent postoperative subgaleal hematoma and periorbital edema.

Temporal Horn Enlargements Predict Secondary Hydrocephalus Diagnosis Earlier than Evans' Index.

The aim of this study was to identify early radiological signs of secondary hydrocephalus. We retrieved neuroradiological data from scans performed at various times in patients who underwent surgery for secondary hydrocephalus due to severe traumatic brain injury (TBI), subarachnoid haemorrhage (SAH), or brain tumour (BT). Baseline measurements, performed on the earliest images acquired after the neurological event (T0), included Evans' index, the distance between frontal horns, and the widths of both temporal horns. The next neuroimage that showed an increase in at least one of these four parameters­and that lead the surgeon to act­was selected as an indication of ventricular enlargement (T1). Comparisons of T0 and T1 neuroimages showed increases in Evans' index, in the mean frontal horn distance, and in the mean right and left temporal horn widths. Interestingly, in T1 scans, mean Evans' index scores > 0.30 were only observed in patients with BT. However, the temporal horn widths increased up to ten-fold in most patients, independent of Evans' index scores. In conclusion temporal horn enlargements were the earliest, most sensitive findings in predicting ventricular enlargement secondary to TBI, SAH, or BT. To anticipate a secondary hydrocephalus radiological diagnosis, clinicians should measure both Evans' index and the temporal horn widths, to avoid severe disability and poor outcome related to temporal lobe damage.

Mini-craniotomy for intra-axial brain tumors: a comparison with conventional craniotomy in 306 patients harboring non-dural based lesions.

The use of a mini-craniotomy approach involving linear skin incision and a bone flap of about 3 cm has been reported for several neurosurgical diseases, such as aneurysms or cranial base tumors. More superficial lesions, including intra-axial tumors, may occasionally raise concerns due to insufficient control of the tumor boundaries. The convenience of a minimally invasive approach to intrinsic brain tumors was evaluated by comparing 161 patients who underwent mini-craniotomy (MC) for intra-axial brain tumors with a group of 145 patients operated on by the same surgical team through a conventional craniotomy (CC). Groups were propensity-matched for age, preoperative condition, size and location of the tumor, and pathological diagnosis. Results were analyzed focusing on operative time, the extent of resection, clinical outcome, hospitalization time, and time to start adjuvant therapy. Mini-craniotomy was equally effective in terms of extent of resection (GTR: 70.9% in the MC group vs 70.5% in the CC group) but had shorter operative time (average: 165 min in the MC group vs 205 min in the CC group p < 0.001) and lower rate of postoperative complications both superficial (1.03% vs 6.5% in the CC group p = 0.009) and deep (4% in the MC group vs 5.5% in the CC group p = 0,47). No relationship was found between the size or location of the tumor and resection rate. The MC group had reduced hospitalization time (average: 5.8 days vs 7.6 in CC group p < 0.001) and faster access to adjuvant therapies. 92.5% of the MC patients, which were scheduled for treatment, started radiotherapy within 8 weeks after surgery as opposed to 84.1% in the CC group (p = 0.04). These findings support the increasing use of mini-craniotomy for intra-axial brain tumors.

Intramedullary spinal cord tumors: the value of intraoperative neurophysiological monitoring in a series of 57 cases from two Italian centers.

BACKGROUND: Intramedullary spinal cord tumors are rare lesions of the central nervous system. Anatomical, molecular and radiological features are well defined, but correct management is still matter of debate. Pertinent literature has reported conflicting opinions regarding the use of intraoperative electrophysiological monitoring (IONM) in the surgical treatment of this kind of lesions, recently. We report a retrospective study from two Italian centers, in order to highlight the usefulness of IONM in the management of intramedullary lesions. METHODS: We performed a retrospective review of patients with intramedullary spinal tumor who underwent surgical resection from February 2011 to February 2018 in two different institutions. Clinical and radiological data, lesion features, timing of symptom onset and IONM findings were recorded. The IONM included somatosensory-evoked potentials (SSEP), motor-evoked potentials (MEP) and D-Wave whenever possible. We evaluated the outcome according to the Modified McCormick scale. We also evaluated the accuracy and relevance of surgical outcomes for each evoked potential (SSEP, MEP, D-Wave). RESULTS: A total of 57 patients were included. A gross total removal was achieved in 46 cases. Neurological follow-up was assessment at 3 days, and 3 and 6 months after surgery. Comparing the preoperative status and 6 months follow-up: the modified McCormick scale showed a neurological stability for 30 patients (52.63%), a worsening of neurological status for 7 patients (12.28%) and an improvement for 20 patients (35.08%). IONM presented high accuracy (sensibility of 100% and specificity of 95.65%) and significantly predicted postoperative permanent motor deficits (P<0.0001; AUC=0.978). D-Wave appeared to have significant greater predictive value than MEP and especially SSEP alone (0.967 vs 0.722 vs 0.542; P=0.044 and P<0.001 respectively). CONCLUSIONS: The gold standard in the intramedullary lesion treatment is maximal safe resection with good neurological outcome, as shown in our patients. The use of IONM is helpful in intramedullary tumors resection in order to minimize postoperative neurological deficits and our analysis suggests that the use of D-Wave presents a statistically significant higher accuracy for predicting postoperative deficits than SSEP and MEP alone.

Factor XI deficiency and delayed hemorrhages after resection of choroid plexus papilloma: illustrative case.

BACKGROUND: Factor XI deficiency, also known as hemophilia C, is a rare inherited bleeding disorder that may leave routine coagulation parameters within normal range. Depending on the mutation subtype, prolonged activated partial thromboplastin time may occasionally be found. The disease has an autosomal transmission, with an estimated prevalence in the general population of approximately 1 in 1 million. Heterozygosis accounts for partial deficits, but the tendency to bleed is unrelated to the measured activity of factor XI. Diagnosis usually follows unexpected hemorrhages occurring spontaneously or after trauma or surgical procedures. OBSERVATIONS: Few cases have been reported in the neurosurgical literature, all occurring spontaneously or after head trauma. Owing to its subtle features, the true incidence of the disease is probably underestimated. The authors report a case of a patient with previously undiagnosed factor XI deficiency who underwent uncomplicated resection of a fourth-ventricle papilloma and experienced delayed, severe hemorrhagic complications. LESSONS: The known association between choroid plexus tumors and intracranial bleeding raised differential diagnosis issues. This report may serve to help to investigate delayed hemorrhages after cranial surgery.

Microsurgical versus endoscopic trans-sphenoidal approaches for clivus chordoma: a pooled and meta-analysis.

Chordoma is a rare slow-growing neoplastic bone lesion. However, they show an invasive local growth and high recurrence rate, leading to an overall survival rate of 65% at 5 years and 35% at 10 years. We conducted a pooled and meta-analysis comparing recurrence rate, post-operative-complications, and survival in patients undergoing either microsurgical (MA) or endoscopic approaches (EA). Search of literature was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines to identify surgical series of clivus chordomas published between January 1990 and March 2018 on Pubmed, Scopus, and Cochrane. Two different statistical analyses have been performed: a pooled analysis and a single-arm meta-analysis of overall recurrence rate and subgroup meta-analysis of complications in the subgroups open surgery and endoscopic surgery. After full-text screening, a total of 58 articles were included in the pooled analysis and 27 studies were included for the study-level meta-analysis. Pooled analysis-the extent of resection was the only association that remained significant (subtotal: HR = 2.18, p = 0.004; partial: HR = 4.40, p < 0.001). Recurrence was more prevalent among the surgical patients (45.5%) compared to endoscopic ones (23.7%). Meta-analysis-results of the cumulative meta-analysis showed an overall rate of recurrence of 25.6%. MA recurrence rate was 31.8% (99% CI 14-52.8), EA recurrence rate was 19.4% (5.4-39.2). CSF leak rate for the endoscopic group was 10.3% (99%CI 5-17.3) and 9.5% (99%CI 1.2-24.6) for the open surgery group. The partial removal versus total removal has an influence on recurrence rate (p < 0.001). MA recurrence rate was 31.8%; EA recurrence rate was 19.4%. The extent of resection is confirmed as a statistically significant factor affecting the risk for recurrence both with the pooled analysis and with the meta-analysis. Meta-analysis demonstrated that older patients tend to recur more than young patients, especially in surgical group.

Intracranial meningioma and concomitant cavernous malformation: A series description and review of the literature.

OBJECTIVES: Intracranial meningioma with concomitant cavernous malformation has been rarely described in the literature. This study aimed to investigate the correct neurosurgical conduct. PATIENTS AND METHODS: We retrieved clinical and radiological data for 39 outpatients or patients that underwent surgery (mean age: 60 years; n = 25 females) for a single or multiple meningiomas and concomitant single or multiple cavernous malformations. Cavernous malformations were classified according to Zabramski's type scale. Our results were compared to results published in the literature. RESULTS: All patients had at least one meningioma and at least one concomitant cavernous malformation. Most meningiomas and cavernous malformations were located in the supratentorial region. Nine patients (23 %) had multiple meningiomas and nine had concomitant multiple cavernous malformations. Cavernous malformations were classified as type I (n = 0), type II (n = 9), type III (n = 11), or type IV (n = 19). The surgical priority was meningioma removal. A single patient underwent simultaneous removal of a meningioma and a contiguous cavernous malformation. In the postoperative period and long term follow-up, no complications occurred related to cavernous malformations, intra- or extra-lesional bleeding, or morphology/size changes. Years after surgical treatment, a new type IV cavernous malformation occurred in two patients. CONCLUSION: Our findings corroborate that meningioma removal should take priority in patients with intracranial meningioma and concomitant cavernous malformation. Concomitant cavernous malformations showed no change in morphology or size; therefore, they should merely be observed during follow-up. In patients that harbor a single meningioma, a type IV cavernous malformation should preferably be considered a concomitant cerebral microbleed.

Arachnoid cyst in young soccer players complicated by chronic subdural hematoma: personal experience and review of the literature.

Arachnoid cysts (ACs) are congenital intracranial benign cavities originating from the meninges during embryological development. Several studies have shown the existence of a relationship between AC and a higher risk to develop ipsilateral chronic subdural hematoma (CSH) especially in a young population. In the presence of an AC, the practice of sport activities may expose young patients to minor head trauma and to an increased risk of developing CSH. We describe three cases of young soccer players with AC associated with CSH. Then, we performed a literature review of all the reported cases in the literature of patients younger than 18 years with AC-associated CSH related to sport practice. A total of 33 cases, including the three cases reported by us, are analyzed. Soccer is the most represented sport activity in this association (39% of cases). The treatment of choice is surgical in all patients, with burr hole or craniotomy in similar proportions. In one-third of patients, the AC has been fenestrated. Outcome is good in all the reported cases. We reviewed the main pathogenic theories, the main surgical strategies described in literature, as well as recurrence rate of CSH, the association of AC and cranial deformities, and the clinical outcome. AC might be associated with skull deformities, but their real incidence remains unclear. The clinical detection of such anomalies should suggest performing further radiological investigations. If the presence of AC is confirmed, the practice of sport activities should not be avoided, as the real incidence of AC-associated CSH is not clear yet and the reported outcomes in literature are good. Surgical treatment of AC-associated CSH should be hematoma removal through burr hole, reserving AC fenestration only for cases with intracystic bleeding or recurrences. The surgeon should adequately advise and inform the young patients and their families that they could have an increased risk of developing CSH given by the presence of the AC, and that they should be referred to a neurosurgical center if they become symptomatic.

Management and Surgical Approaches of Brainstem Cavernous Malformations: Our Experience and Literature Review.

INTRODUCTION: Brainstem cavernous malformations (BSCMs) are clusters of dilated sinusoidal channels. Clinical presentation is characterized by focal neurological deficits and/or hemorrhage. The goal of this study is to analyze surgical indications and approaches in a series of patients with BSCM and review pertinent literature and suggest prognostic factors related to the anatomical, clinical, and surgical data collected. METHODS: We retrospectively reviewed the clinical data of 55 patients with BSCM, treated at three centers, from January 2006 to March 2016. We collected anagraphic data, pre and postoperative neurological status, pre and postradiological images, surgical procedures, and follow-up results. We summarized the anatomical, clinical, and surgical aspects of the lesions and identified two large groups based on the chosen approach: lateral and medial. Clinical and radiological results were then compared. RESULTS: The series comprised 55 patients. Hemorrhagic onset was observed in all patients. Suboccipital, retrosigmoid, anterior, subtentorial, subtemporal, transvermian, telovelar, far lateral and trans, and infratentorial approaches were performed. Neurological status improved postoperatively in 34 cases at last follow-up. Five patients showed clinical neurological worsening. Total resection was achieved in 46 cases and, during a mean follow-up of 63.4 months, no recurrence or re-bleeding occurred in those patients. The mean follow-up was 63.9 months. The mean modified Rankin Scale at final follow-up was used to analyze the results and draw our conclusions. CONCLUSIONS: A reasonable surgical approach, selection, and gentle handling of the surrounding structures are required to prevent impairment of neurologic function and avoid partial resection.

Chiari Malformations.

BACKGROUND: Chiari malformations (CM) represent a group of anomalies characterized by descent of the cerebellar tonsils or vermis into the cervical spinal canal. These malformations can be associated with abnormalities such as hydrocephalus, spina bifida, hydromyelia, syringomyelia, curvature of the spine (kyphosis and scoliosis) and tethered cord syndrome. Hereditary syndromes and other disorders that affect growth and bone formation-such as craniosynostosis, Ehlers-Danlos syndromes and Klippel-Feil syndrome-can also be associated with CM. METHODS: The literature concerning treatment is large, and an extensive range of therapeutic protocols have been described. The literature is inclined in favour of surgery; however, there is controversy over when to perform surgery and which procedure is most appropriate. Lately, the indications for stabilization have been under discussion. RESULTS AND CONCLUSION: In this paper we review the literature and discuss the historical background, anatomical forms, pathophysiology, clinical presentation, relationships with other diseases and diagnostic procedures for these abnormalities.

Development of a delayed acute epidural hematoma following contralateral epidural hematoma evacuation: case report and review of literature.

The formation of a post-traumatic delayed epidural hematoma (DEDH) is a rare but well-described complication in the literature. It is defined as an extradural bleeding not evident at the first computed tomography (CT) scan performed after trauma, but evidenced by further radiological evaluations. The most supported hypothesis about the mechanism responsible for the formation of a DEDH concerns above all the loss of a tamponade effect given by the reduction of intracranial pressure with medical or surgical treatment. A 30-year-old man was admitted to the emergency department with an epidural hematoma (EDH) associated with a linear calvarial bitemporal coronal fracture. A few hours after the surgical procedure for hematoma evacuation, the patient developed a DEDH contralateral to the site of surgical procedure. The literature review identified other 27 analogue cases. The presence of a calvarial fracture contralateral to the site of a craniotomy and the intraoperative brain swelling during EDH removal are suspicious for the development of DEDH. A CT scan has to be urgently performed in this situation. The timing of postoperative radiological examinations after EDH removal has to consider possible complications and has to be balanced on the basis of patient's clinical condition and neuroradiological data, such as skull fractures or intraoperative anomalies. The development of a DEDH after the surgical removal of an EDH is a rare event, characterized by a high mortality rate. DEDH develops preferentially on the contralateral side and with a concomitant skull fracture.

Recurrent lumbar disc herniation: Is there a correlation with the surgical technique? A multivariate analysis.

PURPOSE: The recurrence of a lumbar disc herniation (LDH) is a common cause of poor outcome following lumbar discectomy. The aim of this study was to assess a potential relationship between the incidence of recurrent LDH and the surgical technique used. Furthermore, we tried to define the best surgical technique for the treatment of recurrent LDH to limit subsequent recurrences. MATERIALS AND METHODS: A retrospective study was conducted on 979 consecutive patients treated for LDH. A multivariate analysis tried to identify a possible correlation between (1) the surgical technique used to treat the primary LDH and its recurrence; (2) technique used to treat the recurrence of LDH and the second recurrence; and (3) incidence of recurrence and clinical outcome. Data were analyzed with the Pearson's Chi-square test for its significance. RESULTS: In 582 cases (59.4%), a discectomy was performed, while in 381 (40.6%), a herniectomy was undertaken. In 16 cases, a procedure marked as "other" was performed. Among all patients, 110 (11.2%) had a recurrence. Recurrent LDH was observed in 55 patients following discectomy (9.45%), in 45 following herniectomy (11.8%), and in 10 (62.5%) following other surgery. Our data showed that 90.5% of discectomies and 88.2% of the herniectomies had a good clinical outcome, whereas other surgeries presented a recurrence rate of 62.5% (Pearson's χ2< 0.001). No statistical differences were observed between discectomy or herniectomy, for the treatment of the recurrence, and the incidence for the second recurrences (P > 0.05). A significant statistical correlation emerged between the use of other techniques and the incidence for the second recurrences (P < 0.05). CONCLUSIONS: The recurrence of an LDH is one of the most feared complications following surgery. Although the standard discectomy has been considered more protective toward the recurrence compared to herniectomy, our data suggest that there is no significant correlation between the surgical technique and the risk of LDH recurrence.

Post traumatic dural sinus thrombosis following epidural hematoma: Literature review and case report.

Dural sinus thrombosis following a head trauma is a rare condition, described in literature along with the lack of consensus regarding diagnosis and management. We present a case of a fifty-year-old man with a head injury and combined supratentorial-subtentorial epidural hematoma who was treated conservatively through the administration of low molecular weight heparin. The diagnosis and management of this condition are discussed based on a literature review. The early diagnosis may prevent potentially treatable poor outcomes.

Spinal epidural hematomas: personal experience and literature review of more than 1000 cases.

OBJECTIVE The goal of this study was to identify factors that contribute to the formation of acute spinal epidural hematoma (SEH) by correlating etiology, age, site, clinical status, and treatment with immediate results and long-term outcomes. METHODS The authors reviewed their series of 15 patients who had been treated for SEH between 1996 and 2012. In addition, the authors reviewed the relevant international literature from 1869 (when SEH was first described) to 2012, collecting a total of 1010 cases. Statistical analysis was performed in 959 (95%) cases that were considered valid for assessing the incidence of age, sex, site, and clinical status at admission, correlating each of these parameters with the treatment results. Statistical analysis was also performed in 720 (71.3%) cases to study the incidence of etiological factors that favor SEH formation: coagulopathy, trauma, spinal puncture, pregnancy, and multifactorial disorders. The clinical status at admission and long-term outcome were studied for each group. Clinical status was assessed using the Neuro-Grade (NG) scale. RESULTS The mean patient age was 47.97 years (range 0-91 years), and a significant proportion of patients were male (60%, p < 0.001). A bimodal distribution has been reported for age at onset with peaks in the 2nd and 6th decades of life. The cause of the SEH was not reported in 42% of cases. The etiology concerned mainly iatrogenic factors (18%), such as coagulopathy or spinal puncture, rather than noniatrogenic factors (29%), such as genetic or metabolic coagulopathy, trauma, and pregnancy. The etiology was multifactorial in 11.1% of cases. The most common sites for SEH were C-6 (n = 293, 31%) and T-12 (n = 208, 22%), with maximum extension of 6 vertebral bodies in 720 cases (75%). At admission, 806 (84%) cases had moderate neurological impairment (NG 2 or 3), and only lumbar hematoma was associated with a good initial clinical neurological status (NG 0 or 1). Surgery was performed in 767 (80%) cases. Mortality was greater in patients older than 40 years of age (9%; p < 0.01). Sex did not influence any of these data (p > 0.05). CONCLUSIONS Factors that contribute to the formation of acute SEH are iatrogenic, not iatrogenic, or multifactorial. The treatment of choice is surgery, and the results of treatment are influenced by the patient's clinical and neurological status at admission, age, and the craniocaudal site.