Craniotomy Burr Hole Covers: A Comparative Study of Biomechanical, Radiological, and Aesthetic Outcomes Using 3 Different Plug Materials.

Burr holes in the cranial vault are usually made during trephination for craniotomy or drainage of chronic subdural hematomas. The resulting cranial defect might bring to unsatisfactory esthetic outcome. In the current study the authors report clinical data regarding a cohort of patients who were treated with 3 different types of burr hole covers; autologous bone dust from skull trephination, and 2 different types of cylindric plug made out of porous hydroxyapatite in order to evaluate medium and long-term esthetic and radiological outcomes. Twenty patients were consecutively enrolled in the study and in each patient all 3 types of materials were used to cover different holes. Clinical and radiological outcomes at 6 and 12 months, were analyzed for all 3 types of plugs in terms of thickness of the graft coaptation of margins, remodeling, fractures, mobilization, and contour irregularities. In all craniotomy holes filled with autologous bone dust the authors have observed partial or complete bone reabsorption at 1 year and in 60% of the cases a visible and palpable cranial vault contour irregularity was reported. Both types of bone substitutes gave satisfactory results, comparable to autologous bone dust at 6 months and superior at 12 months, especially in terms of thickness and esthetic appearance. Hydroxyapatite plugs have shown better esthetic and biomechanical results and higher patients' satisfaction compared to autologous bone dust while not giving any additional complications.

Learning curve and influencing factors of performing microsurgical anastomosis: a laboratory prospective study.

Despite being a critical component of any cerebrovascular procedure, acquiring skills in microsurgical anastomosis is challenging for trainees. In this context, simulation models, especially laboratory training, enable trainees to master microsurgical techniques before performing real surgeries. The objective of this study was to identify the factors influencing the learning curve of microsurgical training. A prospective observational study was conducted during a 7-month diploma in microsurgical techniques carried out in the anatomy laboratory of the school of surgery. Training focused on end-to-end (ETE) and end-to-side (ETS) anastomoses performed on the abdominal aorta, vena cava, internal carotid and jugular vein, femoral artery and vein, caudal artery, etc. of Wistar strain rats under supervision of 2 expert anatomical trainers. Objective and subjective data were collected after each training session. The 44 microsurgical trainees enrolled in the course performed 1792 anastomoses (1577 ETE, 88%, vs. 215 ETS, 12%). The patency rate of 41% was independent from the trainees' surgical background and previous experience. The dissection and the temporary clamping time both significantly decreased over the months (p < 0.001). Technical mistakes were independently associated with thrombosis of the anastomoses, as assessed by the technical mistakes score (p < 0.01). The training duration (in weeks) at time of each anastomosis was the only significant predictor of permeability (p < 0.001). Training duration and technical mistakes constituted the two major factors driving the learning curve. Future studies should try and investigate other factors (such as access to wet laboratory, dedicated fellowships, mentoring during early years as junior consultant/attending) influencing the retention of surgical skills for our difficult and challenging discipline.

Surgical treatment of solitary intradural extramedullary spinal cord metastases from solid cancers of non-neurogenic origin. A multicenter study.

PURPOSE: Intradural extramedullary spinal metastases (IESM) represent an extremely rare manifestation of systemic cancer. We evaluated the surgical indications, complications and outcome in a series of 43 patients with solitary intradural extramedullary metastases originating from solid cancer of non-neurogenic origin. METHODS: Patients' age, histopathological diagnoses of primary cancer, tumor size, spinal location, and extramedullary tumor dissemination were collected. Preoperative functional status, pre- and post-operative neurological status, extent of the tumor resection were also analyzed. RESULTS: The majority of IEMS occurred in the thoracic area, with the most common presenting symptoms ranging from motor (76.7%) to sensory (72%) deficits. Gross total resection was achieved in 55.8% of cases, while In 44.2% of patients a subtotal resection was performed due to strong adherence between the tumor and neural tissue. After surgery, 72.1% of patients exhibited improvement of symptoms in terms of pain relief and partial recovery of motor and/or sensory deficits, while neurologic functional status was severely affected postoperatively in 3 patients. CONCLUSION: Although there was no statistical significance between the different parameters and overall survival, KPS and the presence of other metastases were the strongest prognostic factors for overall survival and postoperative neurologic outcome.

Surgical treatment of intramedullary spinal cord metastases: functional outcome and complications-a multicenter study.

Intramedullary spinal cord metastasis (ISCM) is a rare event in the course of advanced malignancy. Management of these lesions remains controversial. Recently, surgery for ISCM has been advocated for selected patients. We performed a retrospective analysis of the clinical course, complications, and outcome of 30 patients surgically treated for ISCM. Patients' age, histopathological diagnoses of primary cancer, tumor size, spinal location, and extramedullary tumor dissemination were collected. Preoperative functional status, pre- and postoperative neurological status, and extent of the tumor resection were also analyzed. Predominant tumor location was thoracic, followed by cervical and conus medullaris. Lung cancer constituted the majority of primary malignancies. In 9 cases, one of the indications for spinal surgery was to obtain a histopathological diagnosis. On admission, all patients presented with neurological symptoms suggestive of myelopathy. After surgery, 18 patients exhibited improvement of symptoms in terms of pain relief and partial recovery of motor and/or sensory deficits; 6 patients were unchanged, while 6 patients exhibited postoperative deterioration. Median survival time after surgery was 9.9 months. Age > 70 years old, presence of systemic metastases, preoperative neurological non functional status, and lung cancer as primary tumor were all factors associated with a worse survival prognosis. This study did not show a clear survival difference between gross total and subtotal ISCM tumor resection. Patients who underwent gross total resection had a worse functional outcome with respect to patients with only partial resection. Gross total resection with low morbidity must be the surgical target, but when not possible, subtotal resection and adjuvant therapy are a valid therapeutic option.

Current patterns of practice in spinal fusion for chronic low back pain-results from a survey at the German Spine Societies' Annual Congress 2018.

BACKGROUND: There is debate regarding criteria to select patients for lumbar fusion surgery who have chronic low back pain (CLBP) and corresponding degenerative changes, but without nerve root compression or neurogenic claudication. The aim of this study was to compare patterns in current practice. METHOD: A total of 143 printed questionnaires containing 51 questions were distributed at the German Spine Societies' (DWG) annual congress, 6-8 December 2018. RESULTS: We received 127 (89%) surveys (64 orthopedic surgeons and 63 neurosurgeons). Excluding the 22% who do not perform lumbar fusion for CLBP, 41.4% reported performing 1-10 lumbar fusion procedures for patients with CLBP per year, 20.2% reported 11-20, 10.1% reported 21-30 and 17.2% reported performing more than 50. A total of 44.9% of surgeons reported treating patients for at least 6-12 months conservatively before considering surgery; 65.6% considered postoperative pain reduction of 50-70% a treatment success; 32.6% of respondents believe that <50% of patients showed good outcomes after fusion in CLBP and only 15.5% believed that 70% or more showed good outcomes. Orthopedic surgeons perform more lumbar fusion surgeries than neurosurgeons (p = 0.05), fuse more lumbar segments than neurosurgeons (p = 0.02) and are more likely to suggest that their patients with CLBP cease smoking preoperatively (p = 0.02). CONCLUSIONS: Despite discouraging evidence in the literature, the majority of respondents still perform fusion surgery in patients with CLBP. The use of preoperative diagnostics and tests vary widely among spine surgeons.

Tumor-to-tumor metastasis of lung adenocarcinoma into a spinal intradural solitary fibrous tumor: a case report.

Solitary fibrous tumors (SFTs) are rare mesenchymal neoplasms commonly involving visceral or parietal pleura. We present the first report of tumor-to-tumor metastasis involving a pulmonary adenocarcinoma donor and an intradural SFT recipient. The patient presented with a 1 year history of diffuse back pain. A spinal intradural contrast-enhancing mass at the T9/10 level and a tumor of the lung were diagnosed radiologically. Bronchoscopic biopsy confirmed pulmonary adenocarcinoma in the right upper lung lobe. Due to deteriorating neurological status with conus medullaris syndrome, we performed a neurosurgical excision of the lesion. Histological analysis of the tumor revealed tumor-to-tumor metastasis of the adenocarcinoma to the SFT.

Successful Strategies for Dealing With Infected, Custom-Made Hydroxyapatite Cranioplasty.

When a cranioplasty implant becomes infected, standard operating procedure dictates its removal and the initiation of a long course of antibiotic therapy. However, removing such a prosthesis can have a series of adverse consequences, including delayed cognitive and motor recovery, lack of brain tissue protection, unsightly deformity, and the need for two additional surgical procedures, not to mention the additional costs involved. To maintain the advantages of cranioplasty, we opted for a conservative approach (levofloxacin and rifampicin every 24 hours for 8 weeks) in a 68-year-old woman whose custom-made porous hydroxyapatite implant, fitted following aneurysm clipping, had become infected. The tissues overlying the implant were curettaged, and the patient's clinical condition, blood markers, and infection course were continuously monitored (local monitoring was performed by single-photon emission computed tomography [SPECT]/computed tomography [CT after intravenous administration of Tc-labeled antigranulocyte antibody). Blood tests and SPECT/CT evidenced a progressive reduction in phlogosis indices and infection locus, even 1 month after antibiotic therapy was commenced, and at 2 years from cranioplasty, the same tests and clinical examination were negative. At 6-year follow-up, clinical assessment revealed nothing out of the ordinary.Hence, specific cases (hydroxyapatite prosthesis, intact dura, cranial CT and magnetic resonance imaging negative for empyema, well-vascularized scalp, antibiotic-responsive bacteria) of infected cranial implant can be treated using a conservative approach consisting of appropriate antibiotic therapy, accompanied by local debridement where necessary, and assiduous monitoring of phlogosis indices and local verification via labeled-leukocyte scintigraphy. Our report, which was compiled after a long-term follow-up period, shows that this conservative procedure appears to be a viable option in cases of infected, custom-made hydroxyapatite cranioplasty, provided that some basic rules concerning clinical and instrumental standards are adhered to, as clearly stated in our report.

Biosurgical Hemostatic Agents in Neurosurgical Intracranial Procedures.

Intraoperative hemostasis during neurosurgical procedures is one of the most important aspects of intracranial surgery. Hemostasis is mandatory to keep a clean operative field and to prevent blood loss and postoperative hemorrhage. In neurosurgical practice, biosurgical hemostatic agents have proved to be extremely useful to complete the more classic use of electrocoagulation. During recent years, many biosurgical topical hemostatic agents were created. Although routinely used during neurosurgical procedures, there is still a great deal of confusion concerning optimal use of these products, because of the wide range of products, as absorbable topical agents, antifibrinolytics agents, fibrin sealants and hemostatic matrix, which perform their hemostatic action in different ways. The choice of the hemostatic agent and the strategy for local hemostasis are correlated with the neurosurgical approach, the source of bleeding, and the neurosurgeon's practice. In this study, the authors review all the different sources of bleeding during intracranial surgical approaches and analyze how to best choose the right topical hemostatic agent to stop bleeding, from the beginning of the surgical approach to the end of the extradural hemostasis after dural closure, along all the steps of the neurosurgical procedure.

Cranioplasty: Review of Materials.

Cranioplasty remains a difficult procedure for all craniofacial surgeons, particularly when concerning the reconstruction of large lacunae in the skull. Considering the significant clinical and economic impact of the procedure, the search for materials and strategies to provide more comfortable and reliable surgical procedures is one of the most important challenges faced by modern craniofacial medicine.The purpose of this study was to compare the available data regarding the safety and clinical efficacy of materials and techniques currently used for the reconstruction of the skull. Accordingly, the scientific databases were searched for the following keywords autologous bone, biomaterials, cranial reconstruction, cranioplasty, hydroxyapatite, polyetheretherketone, polymethylmethacrylate, and titanium. This literature review emphasizes the benefits and weaknesses of each considered material commonly used for cranioplasty, especially in terms of infectious complications, fractures, and morphological outcomes.As regards the latter, this appears to be very similar among the different materials when custom three-dimensional modeling is used for implant development, suggesting that this criterion is strongly influenced by implant design. However, the overall infection rate can vary from 0% to 30%, apparently dependent on the type of material used, likely in virtue of the wide variation in their chemico-physical composition. Among the different materials used for cranioplasty implants, synthetics such as polyetheretherketone, polymethylmethacrylate, and titanium show a higher primary tear resistance, whereas hydroxyapatite and autologous bone display good biomimetic properties, although the latter has been ascribed a variable reabsorption rate of between 3% and 50%.In short, all cranioplasty procedures and materials have their advantages and disadvantages, and none of the currently available materials meet the criteria required for an ideal implant. Hence, the choice of cranioplasty materials is still essentially reliant on the surgeon's preference.

DTI-MRI biomarkers in the search for normal pressure hydrocephalus aetiology: a review.

Normal pressure hydrocephalus (NPH) is a clinical syndrome characterized by gait disturbances, urinary incontinence and dementia. Clinical presentation overlaps with Alzheimer disease (AD). Early recognition thus early intervention (shunting) is important for successful treatment, but lack of a diagnostic test with sufficient sensitivity and specificity complicates the diagnosis. We performed literature search and composed a structured review of imaging biomarkers of NPH. Morphometric studies are not sufficient to diagnose NPH. Hydrocephalus is a common finding in elderly people due to the symmetric brain atrophy and is even more pronounced in patients with AD. The key MRI biomarker seems to be diffusion tensor imaging (DTI). According to recent studies, the DTI analysis of the splenium corporis callosi, posterior limb of internal capsule, hippocampus and fornix combined with measurement of Evans index is a promising MRI biomarker of NPH and could be used for NPH diagnostics and in the differential diagnosis from AD and other dementias.

Failure rates and complications of interspinous process decompression devices: a European multicenter study.

OBJECT Spacers placed between the lumbar spinous processes represent a promising surgical treatment alternative for a variety of spinal pathologies. They provide an unloading distractive force to the stenotic motion segment, restoring foraminal height, and have the potential to relieve symptoms of degenerative disc disease. The authors performed a retrospective, multicenter nonrandomized study consisting of 1108 patients to evaluate implant survival and failure modes after the implantation of 8 different interspinous process devices (IPDs). METHODS The medical records of patients who had undergone placement of an IPD were retrospectively evaluated, and demographic information, diagnosis, and preoperative pain levels were recorded. Preoperative and postoperative clinical assessments in the patients were based on the visual analog scale. A minimum of 3 years after IPD placement, information on long-term outcomes was obtained from additional follow-up or from patient medical and radiological records. RESULTS One thousand one hundred eight patients affected by symptomatic 1- or 2-level segmental lumbar spine degenerative disease underwent placement of an IPD. The complication rate was 7.8%. There were 27 fractures of the spinous process and 23 dura mater tears with CSF leakage. The ultimate failure rate requiring additional surgery was 9.6%. The reasons for revision, which always involved removal of the original implant, were acute worsening of low-back pain or lack of improvement (45 cases), recurrence of symptoms after an initial good outcome (42 cases), and implant dislocation (20 cases). CONCLUSIONS The IPD is not a substitute for a more invasive 3-column fusion procedure in cases of major instability and spondylolisthesis. Overdistraction, poor bone density, and poor patient selection may all be factors in the development of complications. Preoperatively, careful attention should be paid to bone density, appropriate implant size, and optimal patient selection.

The relationship between nervus intermedius anatomy, ultrastructure, electrophysiology, and clinical function. Usefulness in cerebellopontine microsurgery.

BACKGROUND: Although previous studies have described the clinical features of the nervus intermedius (NI), no attempt has yet been made to describe the relationship between the ultrastructural and electrophysiological characteristics of the nervus intermedius and its motor competence. OBJECTIVE: In this study, we analyzed the intraoperative electrophysiological response obtained during vestibular schwannoma surgery. The ultrastructure was studied using electron microscopy. MATERIALS AND METHODS: Thirty-six consecutive patients underwent microsurgery for vestibular schwannoma with cerebellopontine angle tumors. The patients were extensively monitored intraoperatively. Selective stimulation of the nervus intermedius was attempted in all cases. The patients were then examined postoperatively and followed for a minimum of 1 year. Forty-three isolated human brainstems were analyzed to collect the ultrastructural NI data. RESULTS: We found a correlation between the NI motor responses in the perinasal and perioral regions and the ultrastructure characteristics, with few (0.5 %) but large myelinated motor fibers (diameters >12 µm). Both characteristics are consistent with the clinical observation of transient weakness of the levator anguli oris muscle. These observations indicate a relationship between the intraoperative electrophysiological identification of the NI nervus intermedius and its clinical and ultrastructural characteristics. CONCLUSIONS: Identifying the NI in the deformed anatomy of tumors could provide a fixed landmark during cerebellopontine surgery and help prevent damage of the facial nerve.

Globus Lucidus: A porcine study of an intracranial implant designed to deliver closed, repetitive photodynamic and photochemical therapy in glioblastoma.

OBJECTIVE: Herein we describe initial results in a porcine model of a fully implantable device designed to allow closed, repetitive photodynamic treatment of glioblastoma (GBM). METHODS: This implant, Globus Lucidus, is a transparent quartz glass sphere with light-emitting diodes releasing wavelengths of 630 nm (19.5 mW/cm2), 405 nm (5.0 mW/cm2) or 275 nm (0.9 mW/cm2). 5-aminolevulinic acid was the photosensitizing prodrug chosen for use with Globus Lucidus, hence the implants illuminated at 630 nm or 405 nm. An additional 275 nm wavelength-emittance was included to explore the effects of photochemical therapy (PCT) by ultraviolet (UV) light. Twenty healthy domestic pigs underwent right-frontal craniotomies. The Globus Lucidus device was inserted into a surgically created right-frontal lobe cavity. After postoperative recovery, irradiation for up to 30 min daily for up to 14 d, or continuous irradiation for up to 14.6 h was conducted. RESULTS: Surgery, implants, and repeated irradiations using the different wavelengths were generally well tolerated. Social behavior, wound healing, body weight, and temperature remained unaffected. Histopathological analyses revealed consistent leukocyte infiltration around the intracerebral implant sites with no significant differences between experimental and control groups. CONCLUSION: This Globus Lucidus porcine study prepares the groundwork for adjuvant, long-term, repeated PDT of the GBM infiltration zone. This is the first report of a fully implantable PDT/PCT device for the potential treatment of GBM. A preclinical effectivity study of Globus Lucidus PDT/PCT is warranted and in advanced stages of planning.

Distant metastases in meningioma: an underestimated problem.

Meningioma is a common intracranial neoplasm derived from meningothelial cells. Meningiomas are associated with a benign clinical course. However, malignant behaviour such as metastatic disease has been also described. Our aim was to analyze the metastatic pattern taking tumor grading into consideration, and to determine clinical signs of distant metastases in meningiomas. In this systematic review PubMed database was screened for distant meningioma metastases from 1990 to 2012. 95 articles were identified. Only cases with metastasized meningiomas were included in the analysis. Our analysis comprised 115 cases with 164 metastatic lesions. Primary tumors were in 33.9 % grade 1, 20.9 % grade 2, and 40 % grade 3. In 5.2 % the grade was not reported. In 93 % meningiomas were diagnosed and resected before distant metastases occurred. In 6.1 % metastases were identified simultaneously with primary tumors and in 0.9 % metastases were identified before the primary tumor was found. The metastatic lesions were localized most frequently in the lung (37.2 %), bones (16.5 %), intraspinally (15.2 %), and in the liver (9.2 %). Other locations were rarer. The size of the metastases varied from 0.6 to 28 cm (median size, 3 cm). There were no significant differences between sizes of the identified metastases in relation to tumor grading. 50.4 % of distant metastases were clinically manifest and 31.3 % were identified incidentally. In 18.3 % clinical signs were missing. In our review 31.3 % of metastatic meningiomas were found to be clinically silent. The prevalence of metastases in meningioma may be underreported.

Accidental head trauma during care activities in the first year of life: a neurosurgical comparative study.

OBJECTIVES: This study aims to describe clinical-epidemiological data regarding accidental fall injuries occurring during homecare activities among children up to 1 year of age and to compare their outcomes according to the type of trauma. METHODS: We searched four different hospital databases on head injuries from 1999 to 2009. Patients recorded under the descriptors "accidental fall" and "home-related" in the subtext were selected. Patients were classified into two groups: those who flipped over and fell from a changing table (n = 253) and those who fell from the bed sustaining a direct impact from the floor (n = 483). RESULTS: There was no difference between both groups with respect to age, gender, and Glasgow Coma Scale score. However, children who suffered injuries after an accidental fall from the changing table were more likely to require surgery (26/483 vs. 57/253, p < 0.0001), had a mean longer length of stay (LOS, 4 vs. 1 day), and a higher incidence of depressed skull fractures (12/483 vs. 24/253, p < 0.0001). Children with a direct impact from the floor after falling off the bed were expected to suffer from simple linear skull fractures, while those who flipped over the changing table were more likely to present facial, soft tissue, or skeletal injuries. CONCLUSIONS: Children who flipped over a changing table during their homecare activities were more likely to require surgery, showed a higher morbidity, and showed a longer LOS than those who fell down from the bed. These results probably reflect the different impact energy according to each injury mechanism.

"Triple R" tonsillar technique for the management of adult Chiari I malformation: surgical note.

BACKGROUND: Chiari type I malformation is a congenital disorder that is characterized by the caudal extension of the cerebellar tonsils through the foramen magnum into the cervical canal and by a reduced posterior fossa volume. METHODS: We report our surgical technique of reposition, reduction, or resection of the cerebellar tonsils for the management of Chiari I malformation. The procedure was performed in 22 adult patients, in three different centers, with a mean age of 37 years. Clinical complaints included headaches, nuchalgia, vertigo, and upper-limb weakness or numbness. Seven patients had cervical syringomyelia. Symptoms developed within a mean time of 36 months (range, 12-70 months). RESULTS: The cerebellar tonsils were exposed through a dura mater-arachnoid incision at the atlanto-occipital space after a 0.5-cm rimming craniectomy of the occipital bone in all patients. In seven patients the tonsils were resected, in other seven were reduced by subpial coagulation and aspiration, and in the remaining eight patients the tonsils were repositioned after coagulating their surfaces. Three patients had also a posterior fossa arachnoid cyst that was fenestrated in two of them. All patients improved postoperatively. Syringomyelia was reduced in five of seven patients. The mean length of the follow-up period was 12 months. CONCLUSIONS: Selective reposition, reduction, or resection of herniated cerebellar tonsils may improve symptoms in adult patients with Chiari I malformation.

Prognostic scoring system for surgical treatment of intramedullary spinal cord metastases.

Although rare, intramedullary spinal cord metastases (ISCMs) are on the rise, most likely due to prolonged survival and improved outcomes as a result of the advances in cancer treatment for cancer patients. While the management of these lesions remains controversial, surgery for ISCM has recently been advocated for selected patients. We performed a retrospective analysis on 30 patients who were surgically treated for intramedullary spinal cord metastases in order to determine a preoperative prognostic scoring system to guide patient selection for surgical interventions. The scoring system was designed to decide between surgery or other therapeutic procedures. The five parameters selected and employed in the assessment system were: 1) patient's general condition, 2) age, 3) primary site of the cancer, 4) number of other extramedullary metastases and 5) severity of neurologic symptoms. Prognosis could not be predicted from a single parameter. These five factors were added together to give a prognostic score between 1 and 10. The average survival period of patients with a prognostic score between 1 and 3 points was 3 months; 11 patients with a score of 4 and 5 points had a mean survival of 7.63 months, while patients with a prognostic score between 6 and 10 was 14.8 months. According to our prognostic scoring system for surgical treatment of ISCM, surgery should be performed in those patients who score above 6 points, while radiotherapy/chemotherapy or palliative care is recommended for those who score between 1 and 3 points. A prognostic score of 4 and 5 represents a grey area where surgeons must use their judgment on whether to intervene either medically or surgically. This scoring system could facilitate decision-making in the management of patients with intramedullary spinal cord metastases.

Incidence, therapy, and outcome in the management of chronic subdural hematoma in Switzerland: a population-based multicenter cohort study.

Background: Chronic subdural hematoma (cSDH) is a disease affecting mainly elderly individuals. The reported incidence ranges from 2.0/100,000 to 58 per 100,000 person-years when only considering patients who are over 70 years old, with an overall incidence of 8.2-14.0 per 100,000 persons. Due to an estimated doubling of the population above 65 years old between 2000 and 2030, cSDH will become an even more significant concern. To gain an overview of cSDH hospital admission rates, treatment, and outcome, we performed this multicenter national cohort study of patients requiring surgical treatment of cSDH. Methods: A multicenter cohort study included patients treated in 2013 in a Swiss center accredited for residency. Demographics, medical history, symptoms, and medication were recorded. Imaging at admission was evaluated, and therapy was divided into burr hole craniostomy (BHC), twist drill craniostomy (TDC), and craniotomy. Patients' outcomes were dichotomized into good (mRS, 0-3) and poor (mRS, 4-6) outcomes. A two-sided t-test for unpaired variables was performed, while a chi-square test was performed for categorical variables, and a p-value of <0.05 was considered to be statistically significant. Results: A total of 663 patients were included. The median age was 76 years, and the overall incidence rate was 8.2/100,000. With age, the incidence rate increased to 64.2/100,000 in patients aged 80-89 years. The most prevalent symptoms were gait disturbance in 362 (58.6%) of patients, headache in 286 (46.4%), and focal neurological deficits in 252 (40.7%). CSDH distribution was unilateral in 478 (72.1%) patients, while 185 presented a bilateral hematoma with no difference in the outcome. BHC was the most performed procedure for 758 (97.3%) evacuations. CSDH recurrence was noted in 104 patients (20.1%). A good outcome was seen in almost 81% of patients. Factors associated with poor outcomes were age, GCS and mRS on admission, and the occurrence of multiple deficits present at the diagnosis of the cSDH. Conclusion: As the first multicenter national cohort-based study analyzing the disease burden of cSDH, our study reveals that the hospital admission rate of cSDH was 8.2/100,000, while with age, it rose to 64.2/100,000. A good outcome was seen in 81% of patients, who maintained the same quality of life as before the surgery. However, the mortality rate was 4%.

Role of lumbar interspinous distraction on the neural elements.

The interspinous distraction devices are used to treat variable pathologies ranging from facet syndrome, diskogenic low back pain, degenerative spinal stenosis, diskopathy, spondylolisthesis, and instability. The insertion of a posterior element with an interspinous device (ISD) is commonly judged responsive to a relative kyphosis of a lumbar segment with a moderate but persistent increase of the spinal canal and of the foraminal width and area, and without influence on low-grade spondylolisthesis. The consequence is the need of shared specific biomechanical concepts to give for each degenerative problem the right indication through a critical analysis of all available experimental and clinical biomechanical data. We reviewed systematically the available clinical and experimental data about kyphosis, enlargement of the spinal canal, distraction of the interspinous distance, increase of the neural foramina, ligamentous structures, load of the posterior annulus, intradiskal pressure, strength of the spinous processes, degeneration of the adjacent segment, complications, and cost-effectiveness of the ISD. The existing literature does not provide actual scientific evidence over the superiority of the ISD strategy, but most of the experimental and clinical data show a challenging potential. These considerations are applicable with different types of ISD with only few differences between the different categories. Despite--or because of--the low invasiveness of the surgical implantation of the ISD, this technique promises to play a major role in the future degenerative lumbar microsurgery. The main indications for ISD remain lumbar spinal stenoses and painful facet arthroses. A clear documented contraindication is the presence of an anterolisthesis. Nevertheless, the existing literature does not provide evidence of superiority of outcome and cost-effectiveness of the ISD strategy over laminectomy or other surgical procedures. At this time, the devices should be used in clinical randomized independent trials in order to obtain more information concerning the most advantageous optimal indication or, in selected cases, to treat tailored indications.

The nervus intermedius as a variable landmark and critical structure in cerebellopontine angle surgery: an anatomical study and classification.

BACKGROUND: An understanding of the normal topography during cerebellopontine angle surgery is necessary to obviate the anatomical distortions caused by tumors. OBJECTIVE: The aim of this study was to analyze the morphological features of the nervus intermedius (NI) and its related structures in the cerebellopontine angle (CPA). METHODS: Forty-three isolated human brainstems were examined to collect comprehensive morphometric and topographical data of the NI in its course from the brainstem to the ganglion geniculi, and discover its anatomical relationship with the other neurovascular structures in the CPA as well as within the meatus acusticus internus. RESULTS: A total of 84 NI were analyzed. The number of bundles comprising the NI varied from one to five. The mean length of the cisternal segment of the NI was 11.47 mm. In most cases, a vein between the root entry/exit zones of the facial and the vestibulocochlear nerve (VN) was documented. In all cases the NI joined the facial nerve, typically (85 %) distally to the the porus within the meatus acusticus internus. The entry/exit zone of the NI can be categorized into four types: in type A, they arise directly from the brainstem; in type B, they arise solely from the facial nerve; in type C solely from the VN; and in type D, where the bundle or bundles arise from both the brainstem and the VN or the facial nerve. CONCLUSION: The anatomical features of the NI can provide an additional variable landmark and critical structure during cerebellopontine microsurgery. Our study of the nerve's anatomy and topographical relations may contribute to preventing intraoperative nerve injuries.