Integrated spine trauma team protocol: Combined neurosurgical and orthopedic experience for the management of traumatic spinal injuries.

Objectives: During the last decades, spine surgery has grown exponentially. In spite of that, it remains a surgical specialty without a well-defined own certification. It is usually carried out, separately, by neurosurgeons and orthopedic surgeons, even if there is an overlapping of competence and skills. Materials and Methods: In our hospital, from January 2019, a systematic protocol called integrated spine trauma team protocol (ISTTP) was implemented to improve the management of traumatic spinal injuries in a multidisciplinary way. It is characterized by a specific algorithm from diagnosis to postoperative care. According to the new protocol, orthopedic spinal surgeons and neurosurgeons work together as an integrated spine trauma team. The authors analyzed, retrospectively, the results obtained by comparing patients treated before and after the application of the ISTTP. Results: The new protocol allowed a statistically significant reduction in waiting time before surgery and complication rate. Moreover, early discharge of patients was recorded. To the best of our knowledge, this is the first study that described a specific algorithm for a standardized multidisciplinary management of the spinal trauma with combined orthopedic and neurosurgeon expertise. Conclusion: Our preliminary results suggest that the application of our ISTTP leads to better results for treating traumatic spinal injury (TSI).

Theoretical investigations of oxygen vacancy effects in nickel-doped zirconia from ab initio XANES spectroscopy at the oxygen K-edge.

In this study, we present theoretical X-ray absorption near-edge structure (XANES) spectra at the K-edge of oxygen in zirconia containing Ni dopant atoms and O vacancies at varying concentrations. Specifically, our model system consist of a supercell composed of a zirconia (ZrO2) matrix containing two nickel dopants (2Ni), which substitute two Zr atoms at a finite separation. We found the 2Ni atoms to be most stable in a ferromagnetic configuration in the absence of oxygen vacancies. In this system, each Ni atom is surrounded by two shells of O with tetrahedral geometry, in a similar way as in bulk cubic zirconia. The oxygen K-edge XANES spectrum of this configuration shows a pre-edge peak, which is attributable to dipole transitions from O 1s to O 2p states that are hybridized with unoccupied Ni 3d states. The intensity of this pre-edge peak, however, reduces upon the introduction of a single vacancy in the 2Ni-doped zirconia matrix. The corresponding ground state remains ferromagnetic, while one of the nickel atoms adopts a trigonal bipyramidal geometry, and the other one remains in a tetrahedral geometry. Furthermore, the introduction of two vacancies in the 2Ni-doped zirconia results in the two Ni atoms having distorted octahedral and trigonal bipyramidal geometries and being coupled antiferromagnetically in the ground state. Additionally, the oxygen K-edge XANES spectrum shows a further decrease in the intensity of the pre-edge peak, compared to the case of a single vacancy. Thus, the changes in the intensity of the pre-edge peak evidence a major structural change in the local environment around nickel atoms and, by extension, in the zirconia matrix. This change is due to the structural disorder induced by the 2Ni dopants and the O vacancies. Furthermore, the analysis of the XANES signatures shows that the oxidation state of nickel atoms changes with the introduction of oxygen vacancies. Our study therefore shows a possibility to control the oxidation state and magnetic order in a typical diluted magnetic oxide. Such a finding may be crucial for spintronics-related applications.

A minimally invasive approach for giant middle cerebral artery thrombosed aneurysms treatment.

BACKGROUND: Management of complex thrombosed aneurysms of the middle cerebral artery (MCA) is challenging. Lesions not amenable to endovascular techniques or direct clipping might require a bypass procedure with subsequent aneurysm occlusion. Various bypass techniques followed by surgical or endovascular closure of the aneurysm are available, but an unpredictable extension of the thrombus to the parent vessel and/or to perforator vessels can occur. We presented a multidisciplinary technique with the aim to reduce invasiveness and complications. METHODS: We present two patients, harboring a thrombosed giant MCA bifurcation aneurysm, who were treated with a minimally invasive three-steps multimodality procedure. In both cases, through a limited exposure of the sylvian fissure, a side-to-side anastomosis between the two M2 branches was performed, followed in the immediate postop by an endovascular occlusion of the frontal M2 branch, with the aim of transforming a bifurcation aneurysm in a sidewall aneurysm, that was then treated a few days later by flow diverter deployment. RESULTS: Both patients had excellent outcomes and were discharged after 7 days without neurological deficits. CONCLUSIONS: Treatment of complex thrombosed MCA aneurysms is challenging. Side-to-side M2 anastomosis with the aim of transforming a bifurcation aneurysm in a sidewall aneurysm, suitable to be treated few days later by flow diverter deployment, offers a minimally invasive multimodal approach with the possibility of reducing serious complications.

First principles simulations of microscopic mechanisms responsible for the drastic reduction of electrical deactivation defects in Se hyperdoped silicon.

By first principles simulations we systematically investigate Se hyperdoped silicon by computing, for different types of Se complexes, the formation energy as a function of dopant concentration. We identify the microscopic mechanisms responsible for the dramatic reduction of electrical deactivation defects as the dopant concentration approaches the critical value, xc, at which the insulator-to-metal transition occurs. We discuss the electrical properties of Se point defects and Se complexes, shedding light on the formation and the nature of the impurity band in the bandgap and how the presence of different types of complexes may increase the broadening of the impurity band and affects the insulator-to-metal transition. We identify the best doping range in which the properties of the impurity band can be engineered according to the needs of the electronic industry. Simulations of the structural properties of the complexes complete the work. Our findings are relevant for intermediate impurity band applications.

Cerebellopontine Angle Surgery Assisted by Continuous Mapping of the Facial Nerve Via the Ultrasonic Aspirator.

BACKGROUND: Cerebellopontine angle (CPA) surgery carries the risk of lesioning the facial nerve. The goal of preserving the integrity of the facial nerve is usually pursued with intermittent electrical stimulation using a handheld probe that is alternated with the resection. We report our experience with continuous electrical stimulation delivered via the ultrasonic aspirator (UA) used for the resection of a series of vestibular schwannomas. METHODS: A total of 17 patients with vestibular schwannomas, operated on between 2010 and 2018, were included in this study. A constant-current stimulator was coupled to the UA used for the resection, delivering square-wave pulses throughout the resection. The muscle responses from upper and lower face muscles triggered by the electrical stimulation were displayed continuously on multichannel neurophysiologic equipment. The careful titration of the electrical stimulation delivered through the UA while tapering the current intensity with the progression of the resection was used as the main strategy. RESULTS: All operations were performed successfully, and facial nerve conduction was maintained in all patients except one, in whom a permanent lesion of the facial nerve followed a miscommunication to the neurosurgeon. CONCLUSION: The coupling of the electrical stimulation to the UA provided the neurosurgeon with an efficient and cost-effective tool and allowed a safe resection. Positive responses were obtained from the facial muscles with low current intensity (lowest intensity: 0.1 mA). The availability of a resection tool paired with a stimulator allowed the surgeon to improve the surgical workflow because fewer interruptions were necessary to stimulate the facial nerve via a handheld probe.

Complications of Halo Placement.

BACKGROUND: The halo vest is widely used throughout the world to manage craniovertebral and cervical instabilities. It can be used for postoperative immobilization or as an alternative to surgical fixation. METHOD: In this paper we present some cases of severe complications from our own practice and review the literature on halo complications. RESULTS: Like any therapeutic manoeuvre, halo placement may be followed by various complications. In the meantime, modern techniques of fixation offer safe and immediate stabilization. CONCLUSION: The halo vest remains a formidable method for cervical immobilization. However, it should not be used a priori instead of surgery.

Contemporary tools in arteriovenous malformations surgery.

Arteriovenous malformations (AVMs) are rare entities and therefore considered the main challenge for a neurosurgeon. Since the publication of the ARUBA study, one of the most popular debate regards the actual surgical indication for unruptured AVMs. Our group recently published a multicenter review of more than 500 cases underlying the important role of surgery. Over the last few decades, the expanding technologies used in the treatment of AVMs have shown an ongoing improvement overcoming some of the existing difficulties and shortcomings. In this paper, we reviewed the present literature to illustrate the main contemporary tools that, in our opinion, are crucial to obtain the best surgical and clinical outcome. Indocyanin green is nowadays considered a gold standard to identify arterial feeders, draining veins, and to detect any eventual residual. The use of non-stick, bipolar, 2-mm blade microclips, and thulium laser allows to obtain a better bleeding control and nidus removal. The development of the intraoperative ultrasound with neuronavigation, angiosonography, and color-Doppler improves the accuracy of AVM resection. Moreover, improvements have been developed with the use of intraoperative micro-Dopplers combined with flow measurements, which consent to verify the gradual reduction of flow through draining veins. The possibility to perform functional preoperative studies and intraoperative monitoring can be considered as an essential point in the decision making in eloquent or near-eloquent AVMs. Furthermore, the hybrid operating room represents the best expression of an excellent neurovascular team where the use of the intraoperative angiography allows neurosurgeons and neurointerventional radiologists to work at the same time in a combined approach to achieve the best surgical removal.

Torcular Meningioma with Multi-Venous Sinus Invasion: Compensatory Drainage Veins and Surgical Strategy.

BACKGROUND: Torcular meningiomas involving major dural venous sinuses are rare entities and a great challenge for neurosurgeons. The deep knowledge of the patency of occlusion of the sinuses, the extent of the occlusion and potentially new developing of extra and intracranial collateral venous drainage as compensatory venous channels, are at the base of a correct operative strategy. CASE DESCRIPTION: A 45-year-old woman presented with persistent headache. Magnetic resonance imaging of the brain and digital subtraction angiography demonstrated a huge torcular meningioma with complete multi-venous sinus occlusion and a wide venous network for brain and tumor drainage. In these rare cases, we have hypothesized the presence of venous drainage shared by the brain and the tumor, which could generate undesirable venous occlusion during operative resection. This could be a cause of the well-known surgical complications, such as brain swelling and hemorrhagic infarction. CONCLUSIONS: We report our experience with a huge torcular meningioma with multi-venous sinus invasion and a literature review, with a special emphasis on compensatory drainage veins and surgical strategy.

Unruptured Versus Ruptured AVMs: Outcome Analysis from a Multicentric Consecutive Series of 545 Surgically Treated Cases.

BACKGROUND: Recent literature strongly challenged indications to perform preventive surgery in unruptured arteriovenous malformation (AVM) claiming that invasive AVM treatment is associated with a significant risk of complications and thus conservative management may be a preferable alternative in many patients. On the other hand, the recent improvement of surgical instrumentation and treatment strategies (both surgical and interventional) yielded better outcomes than those achieved only a decade ago. Therefore, even among specialists, a wide variety of opinions, concerning the treatment of unruptured AVM, can be found. METHODS: This multicenter retrospective study analyzes a consecutive series of 545 surgically treated AVMs in 10 different hospitals in Italy. RESULTS: Patients with AVMs treated after hemorrhage had an unfavorable (modified Rankin Scale score >1) outcome in more than one third (37.69%) of the cases. Conversely, with proper indications, unruptured AVMs treated preventively have a good outcome in 93.8% of cases, increasing to 95.7%, with no death, if only Spetzler-Martin grades 1-3 are considered (P < 0.05). Outcomes on discharge significantly (P < 0.05) improve at 6 months with the disappearance of many of the initial neurologic deficits that turn out to be transient. CONCLUSIONS: In unruptured low-risk AVMs (Spetzler-Martin grades 1-3), over time, the risk of surgery-associated neurologic deficits becomes lower than that linked to spontaneous hemorrhage, with a crossover point at 6.5 years. Because the average bleeding age is less than 45 years, preventive surgery can be advocated to safeguard the patient and overcome the risks associated with the natural history of AVMs.

Use of Laser in Arteriovenous Malformation Surgery.

BACKGROUND: Arteriovenous malformation surgery is particularly demanding owing to the need to control bleeding of small, deep white matter vessels during and after removal of the nidus; this is probably one of the most critical moments of arteriovenous malformation surgery. The aim of this article is to describe a useful technique based on the use of tweezers to temporarily stop the blood flow followed by coagulation with the thulium laser. METHODS: Surgery was performed in 20 patients with unruptured cerebral arteriovenous malformations. In each case, the superficial feeder vessels were easily coagulated with nonstick bipolar tips. The finer and deeper feeder vessels were coagulated with use of tweezers and thulium laser. RESULTS: All patients were treated successfully. Optimal intraoperative hemostasis was achieved. CONCLUSIONS: Results were good with no postoperative complications. Our results could encourage a more standardized use of the described technique.

European consensus conference on unruptured brain AVMs treatment (Supported by EANS, ESMINT, EGKS, and SINCH).

In December of 2016, a Consensus Conference on unruptured AVM treatment, involving 24 members of the three European societies dealing with the treatment of cerebral AVMs (EANS, ESMINT, and EGKS) was held in Milan, Italy. The panel made the following statements and general recommendations: (1) Brain arteriovenous malformation (AVM) is a complex disease associated with potentially severe natural history; (2) The results of a randomized trial (ARUBA) cannot be applied equally for all unruptured brain arteriovenous malformation (uBAVM) and for all treatment modalities; (3) Considering the multiple treatment modalities available, patients with uBAVMs should be evaluated by an interdisciplinary neurovascular team consisting of neurosurgeons, neurointerventionalists, radiosurgeons, and neurologists experienced in the diagnosis and treatment of brain AVM; (4) Balancing the risk of hemorrhage and the associated restrictions of everyday activities related to untreated unruptured AVMs against the risk of treatment, there are sufficient indications to treat unruptured AVMs grade 1 and 2 (Spetzler-Martin); (5) There may be indications for treating patients with higher grades, based on a case-to-case consensus decision of the experienced team; (6) If treatment is indicated, the primary strategy should be defined by the multidisciplinary team prior to the beginning of the treatment and should aim at complete eradication of the uBAVM; (7) After having considered the pros and cons of a randomized trial vs. a registry, the panel proposed a prospective European Multidisciplinary Registry.

Craniovertebral fusion in an infant using struts of banked adult bone.

PURPOSE: The aim of this paper is to discuss the problems of craniocervical instability and craniocervical fusion in infancy. Despite the relative frequency of carniovertebral joint malformations, actual instability is quite rare in infancy. METHODS: An infant 8 months of age presented with tetraparesis and sleep apnea due to a complex malformation of her craniovertebral joint. An initial attempt at conservative treatment using a rigid neck collar failed, so the patient was surgically managed by the onlay placement of two autologous rib grafts. The rigid collar was maintained for 5 months. RESULTS: Both rib grafts progressively reabsorbed within a few months, while the clinical deficits recurred. Reoperation consisted of occipitocervical interposition of two robust struts of banked cadaveric adult fibula. This time, the skull appeared mature enough to allow immobilization by the halo system. Adequate occipitocervical fusion was eventually achieved, and the patient fully recovered. CONCLUSIONS: To the best of our knowledge, there is no other reported case of an infant undergoing craniovertebral fusion using cadaveric adult bone. When screw placement is not considered advisable to manage small infants, appropriate stability may be obtained using struts of robust cadaveric bone. A meticulous carpentry technique with graft interposition under compression and adequate postoperative immobilization remains mandatory.

The craniovertebral junction area and the role of the ligaments and membranes.

Traumatic injuries of the craniovertebral junction (CVJ) area are common and frequently the outcome of motor vehicle accidents, falls, and diving accidents. To define and characterize CVJ traumatic injuries, some international classifications are currently in use, and they are thought and focused on junction bone fracture. However, recent data point out a major important role of the CVJ ligaments and membranes in traumatic injuries with a secondary function of the osseous structures. Emphasizing the correct role of the ligaments and membranes is extremely important for determining appropriate medical or surgical planning for patients and also to design new CVJ injury classifications. We reviewed every recent major publication on the ligaments and membranes of the CVJ area. We divided the information into sections concerning anatomy, embryology, biomechanics, trauma, and CVJ bone fractures. A role of the ligaments and membranes in the traumatic injuries of the CVJ area has often been recognized; but only recently, with the increase in the knowledge of the anatomic and biomechanical junction area, supported by neuroradiological tools (magnetic resonance imaging) and a more detailed traumatic injuries assessment, has the role of the ligaments and membranes been highlighted. Ligaments and membranes have a pivotal role in each junctional ability and are the key to orienting any medical or surgical indications in this unique area of the spine.

Arterial and venous aneurysms associated with arteriovenous malformations.

OBJECTIVE: To identify prioritization based on hemorrhagic risk and indications for treatment of arterial and venous aneurysms associated with arteriovenous malformation (AVM). METHODS: From a global series of 400 consecutively treated AVMs, 34 patients (8.5%) with 45 arterial or venous aneurysms were extrapolated. These 45 lesions were classified as unrelated aneurysms (n = 5 cases; 11.%), flow-related aneurysms (n = 18 cases; 40%), and intranidal and postnidal venous aneurysms (n = 22; 49.%). The 18 flow-related aneurysms were further divided into remote (n = 6 cases) and adjacent (n = 12 cases) types. Of 45 aneurysms associated with AVMs, 15 were unruptured with a 5-year mean follow-up. Various possible risk indicators were considered and measured by univariate and multivariate analyses. RESULTS: During the follow-up period, 1 of 15 unruptured aneurysms bled, and the patient died. A significantly different bleeding incidence was found between unrelated aneurysm and flow-related aneurysm types (P = 0.002). Bleeding was significantly less probable in flow-related remote aneurysm type than in venous and flow-related adjacent aneurysm types (P = 0.007). The location of the aneurysm was the only true risk factor for bleeding; the other parameters had no influence on bleeding. CONCLUSIONS: In this series, different subtypes of aneurysms associated with AVMs had different clinical behaviors. The bleeding risk of the unrelated aneurysm and the flow-related remote aneurysm types should be considered almost the same as any other unruptured aneurysm. In other words, bleeding risk should be considered taking into account the parameters established by the International Study of Unruptured Intracranial Aneurysms (location, size, and morphology). Conversely, flow-related adjacent aneurysm and venous aneurysm types have significantly higher bleeding potentials.

Asymptomatic lipomas of the medullary conus: surgical treatment versus conservative management.

OBJECT: The goal of this study was to compare long-term results of surgery with the outcomes of conservative treatment in patients with asymptomatic lipomas of the conus medullaris. METHODS: The parents of 56 consecutive children with a diagnosis of asymptomatic lipoma of the conus medullaris underwent detailed neurosurgical consultation. The pros and cons of both prophylactic surgery and conservative treatment were carefully presented. Both options were offered, and the parents were free to choose the preferred management. A total of 32 children underwent surgical treatment, and 24 were conservatively treated. Afterward, all patients entered the same protocol of serial neurological and urological follow-up at the Centro Spina Bifida. The mean follow-up periods were 9.7 years in the surgical treatment group and 10.4 years in the conservative treatment group. RESULTS: Permanent surgical morbidity was 3.1% (1 patient). During follow-up, tethered cord syndrome occurred in 9.7% of the surgically treated patients (3 of 32 patients) and in 29.1% of the conservatively managed children (7 of 24 patients). This difference did not result in statistical significance, but a clear trend in favor of surgery emerged. Young age at surgery and a cord/sac ratio < 50% appeared to be determining factors in the prevention of subsequent tethered cord syndrome. CONCLUSIONS: The small size of this series does not provide enough statistical evidence that surgical treatment can really improve the natural history of asymptomatic lipomas of the conus medullaris. Nevertheless, surgery appears at least advisable since it reduces by 75% the odds of TCS (p = 0.067), which is quite close to statistical significance.

Venous flow rearrangement after treatment of cerebral arteriovenous malformations: a novel approach to evaluate the risks of treatment.

OBJECTIVE: This study aims to identify the angiographic parameters that could help predict the risks of hyperemic complications (HCs) in the treatment of cerebral arteriovenous malformations (AVMs). METHODS: The charts and the pre- and post-treatment angiographies of 400 consecutively treated patients with cerebral AVMs were retrospectively reviewed. Several parameters were analyzed: grade, size, drainage depth, number of the "recruited veins" (veins coming from the brain and joining the main AVM drainage), and "venous times" (the times of visualization of the nidus and the main drainage, of the "recruited veins," and finally of the normal cerebral veins). On this basis, two groups were identified: group 1, consisting of 309 patients (77.3%) with normal/subnormal venous times, and group 2, consisting of 91 patients (22.7%) with altered venous times and venous engorgement. Finally, the weight of the various parameters was measured by univariate and multivariate analyses. RESULTS: An overall number of 245 patients (61.2%) achieved favorable outcomes. HCs occurred in a total of 28 patients (7%): No patient belonged to group 1, so that these adverse effects were reported in 30.7% of group 2 patients. The presence of deep drainage and the number of recruited veins resulted in statistically significantly different impacts on the risk of the different grades. CONCLUSIONS: The statistical analysis allowed the identification of three different risk scores, which were named Nig-scores (Niguarda scores). Nig-score 0 means no risk of HCs and concerns patients without altered venous times; Nig-score 1 represents patients with intermediate risk, that is, with moderately altered venous times and few recruited veins; Nig-score 2 indicates high risk of HCs and refers to patients with markedly altered venous times.

Traumatic injuries to the craniovertebral junction: a review of rare events.

The craniovertebral junction is a specific region of the spine with unique anatomical and biomechanical properties that yields a wide variety of injury patterns. Junctional traumatic fractures and/or dislocations are widely reported in clinical practice, but we could identify only a subgroup of upper cervical spine traumatic injuries with very few cases reported in the literature, and for this reason may be considered rare. In some of these cases, the absence of spinal biomechanical instability, in association with moderate clinical symptoms (neck stiffness and pain) and the difficulty in fracture identification through standard cervical radiographs, leads to a high percentage of missed injuries. In other cases, traumatic events have been commonly described only in autopsy series due to the high degree of spinal biomechanical instability. Herein, we have summarized all the relevant literature concerning this issue and also included our cases, with the aim of emphasizing prompt diagnosis and correct management. We provide a guide for correctly identifying "rare" craniovertebral junction traumatic injuries.

Donor wave functions delocalization in silicon nanowires: the peculiar [011] orientation.

The localization of the donor electron wave function can be of key importance in various silicon applications, since for example it determines the interactions between neighboring donors. Interestingly, the physical confinement of the electrons in quasi-one-dimensional nanostructures, like silicon nanowires, noticeably affects this property. Using fully ab initio calculations, we show that the delocalization of the donor electron wave function along the axis of a nanowire is much greater in [011] oriented nanowires for phosphorus and selenium donors. We also demonstrate that its value can be controlled by applying a compressive or tensile uniaxial strain. Finally, we discuss the implications of these features from both an experimental and a theoretical point of view.

Vittorio Marchi, MD (1851-1908): an unsung pioneer of neuroscience.

Vittorio Marchi was an Italian neuroscientist who lived during the second half of the 19th century. He is generally remembered for developing a novel staining method to trace the degeneration of nervous fibers in lesions of the central nervous system. This osmium-based method was used worldwide for approximately a century and continues to be cited in modern textbooks. Despite several important original scientific contributions, Marchi was never awarded a university chair. Discouraged, he left to practice neurology in a rural area but continued to write outstanding articles, and in 1897, he became a pioneer of meningioma surgery. Today, he is remembered only in specialized contexts. We hope this article can provide the recognition that Marchi deserves.

Traumatic (type II) odontoid fracture with transverse atlantal ligament injury: a controversial event.

OBJECTIVE: Traumatic (Type II) odontoid fractures are very common injuries. Nevertheless, their connection with transverse atlantal ligament injury is controversial and poorly defined. The aim of this study is to report a single case of traumatic (type II) odontoid fracture with transverse atlantal ligament injury and to critically analyze the role of ligaments and membranes together with neuroradiological tools in the management of craniovertebral junction-traumatized patients. METHODS: We report 27 consecutive cases of traumatic (type II) odontoid fractures who underwent magnetic resonance imaging (MRI) in the acute phase injury (<72 hours), focusing our attention on the transverse atlantal ligament. RESULTS: One patient (3.7%) demonstrated a transverse atlantal ligament injury on MRI. The patient underwent surgery. CONCLUSIONS: Traumatic (type II) odontoid fracture with transverse atlantal ligament avulsion can be considered an unusual event. It is our opinion that the routine use of MRI for all patients with type II odontoid fracture could be unjustified in clinical practice. Strict clinical surveillance of all patients managed conservatively and the use of MRI in selected cases could be a reasonable management option.