TN-RS: a novel scoring system predicts Gamma Knife Radiosurgery outcome for trigeminal neuralgia patients.

BACKGROUND: Gamma Knife Radiosurgery (GKRS) is an effective treatment option for medically refractory trigeminal neuralgia (TN). This study examines GKRS outcome in a large cohort of TN patients and highlights pretreatment factors associated with pain relief. METHODS: This is a single-center retrospective analysis of patients treated with GKRS for TN between 2011 and 2019. Pain relief was assessed at 1 year, and 2-3 years following GKRS. Multivariable analysis identified several factors that predicted pain relief. These predicting factors were applied to establish a pain relief scoring system. RESULTS: A total of 162 patients met inclusion criteria. At 1 year post-GKRS, the breakdown of Barrow Neurological Institute (BNI) score for pain relief was as follows: 77 (48%) score of I, 13 (8%) score of II, 37 (23%) score of III, 22 (14%) score of IV, and 13 (8%) score of V. Factors that were significantly associated with pain-free outcome at 1 year were: Typical form of TN (OR = 2.2 [1.1, 4.9], p = 0.049), No previous microvascular decompression (OR = 4.4 [1.6, 12.5], p = 0.005), Response to medical therapy (OR = 2.7 [1.1, 6.1], p = 0.018), and Seniority > 60 years (OR = 2.8 [1.4, 5.5], p = 0.003). The term "Trigeminal Neuralgia-RadioSurgery" was used to create the TN-RS acronym representing the significant factors. A stepwise increase in the median predicted probability of pain-free outcome at 1 year from 3% for patients with a score of 0 to 69% for patients with a maximum score of 4. CONCLUSION: The TN-RS scoring system can assist clinicians in identifying patients that may benefit from GNRS for TN by predicting 1-year pain-free outcomes.

Prevalence and Characteristics of Cervical Ossified Posterior Longitudinal Ligament in the Jewish Population.

BACKGROUND: Numerous studies have demonstrated an association between ethnic identity and the prevalence rate of cervical ossified posterior longitudinal ligament (C-OPLL). To date, its prevalence rate in the Jewish population has not been determined. The aim of this historical prospective study is to evaluate the prevalence and characteristics of C-OPLL in the Jewish population. METHODS: We performed a retrospective evaluation of imaging studies of all adult patients who underwent both cervical computed tomography and magnetic resonance imaging for all clinical indications within a span of 36 months between January 2017 and July 2020 at a single tertiary referral hospital located in central Israel. Identified C-OPLL carriers were interviewed by telephone. All the patients provided informed consent and then were questioned for current symptoms and demographics, including religion, Jewish ethnic identity, birthplace, parental birthplace and ethnic identity, and family history of spinal disorders. RESULTS: Overall, 440 participants were radiographically evaluated. The prevalence of C-OPLL in the Jewish population was 7.5% (33 of 440). The mean age of the C-OPLL carriers was 65.8 years. All the C-OPLL carriers were symptomatic at analysis. The carriers had an increased proportion with a Sephardic Jewish ethnic identity (65.4%), with a significantly high rate of homogeneous parental Jewish identity (92.4%), suggesting a prominent genetic contribution to the development of this condition. CONCLUSIONS: The prevalence of C-OPLL in the Jewish population in central Israel was 7.5%. This rate is significantly higher than that in other previously studied populations. To the best of our knowledge, this is the first study to identify the Jewish population as experiencing an increased prevalence of C-OPLL.

MRI-based detection of cervical ossification of the posterior longitudinal ligament using a novel automated machine learning diagnostic tool.

OBJECTIVE: Currently, CT is considered the gold standard for the diagnosis of ossification of the posterior longitudinal ligament (OPLL). The objective of this study was to develop artificial intelligence (AI) software and a validated model for the identification and representation of cervical OPLL (C-OPLL) on MRI, obviating the need for spine CT. METHODS: A retrospective evaluation was performed of consecutive imaging studies of all adult patients who underwent both cervical CT and MRI for any clinical indication within a span of 36 months (between January 2017 and July 2020) in a single tertiary-care referral hospital. C-OPLL was identified by a panel of neurosurgeons and a neuroradiologist. MATLAB software was then used to create an AI tool for the diagnosis of C-OPLL by using a convolutional neural network method to identify features on MR images. A reader study was performed to compare the performance of the AI model to that of the diagnostic panel using standard test performance metrics. Interobserver variability was assessed using Cohen's kappa score. RESULTS: Nine hundred consecutive patients were found to be eligible for radiological evaluation, yielding 65 identified C-OPLL carriers. The AI model, utilizing MR images, was able to accurately segment the vertebral bodies, PLL, and discoligamentous complex, and detect C-OPLL carriers. The AI model identified 5 additional C-OPLL patients who were not initially detected. The performance of the MRI-based AI model resulted in a sensitivity of 85%, specificity of 98%, negative predictive value of 98%, and positive predictive value of 85%. The overall accuracy of the model was 98%, with a kappa score of 0.917. CONCLUSIONS: The novel AI software developed in this study was highly specific for identifying C-OPLL on MRI, without the use of CT. This model may obviate the need for CT scans while maintaining adequate diagnostic accuracy. With further development, this MRI-based AI model has the potential to aid in the diagnosis of various spinal disorders and its automated layers may lay the foundation for MRI-specific diagnostic criteria for C-OPLL.

The Evolution of Minimally Invasive Spine Tumor Resection and Stabilization: From K-Wires to Navigated One-Step Screws.

Minimization of the surgical approaches to spinal extradural metastases resection and stabilization was advocated by the 2012 Oncological Guidelines for Spinal Metastases Management. Minimally invasive approaches to spine oncology surgery (MISS) are continually advancing. This paper will describe the evolution of minimally invasive surgical techniques for the resection of metastatic spinal lesions and stabilization in a single institute. A retrospective analysis of patients who underwent minimally invasive extradural spinal metastases resection during the years 2013-2019 by a single surgeon was performed. Medical records, imaging studies, operative reports, rates of screw misplacement, operative time and estimated blood loss were reviewed. Detailed description of the surgical technique is provided. Of 138 patients operated for extradural spinal tumors during the study years, 19 patients were treated in a minimally invasive approach and met the inclusion criteria for this study. The mortality rate was significantly improved over the years with accordance of improve selection criteria to better prognosis patients. The surgical technique has evolved over the study years from fluoroscopy to intraoperative 3D imaging and navigation guidance and from k-wire screw insertion technique to one-step screws. Minimally invasive spinal tumor surgery is an evolving technique. The adoption of assistive devices such as intraoperative 3D imaging and one-step screw insertion systems was safe and efficient. Oncologic patients may particularly benefit from the minimization of surgical decompression and fusion in light of the frailty of this population and the mitigated postoperative outcomes associated with MIS oncological procedures.

C1 lateral mass screw insertion using cannulated, navigated screws: preliminary results of a novel technique.

PURPOSE: The upper cervical spine region is densely populated by neural and vascular structures impeding the approach for fusion surgery. Technological advancement simplify the approach to C1-C2 fusion, thus reduce risks. The current paper purpose is to describe initial experience with a novel technique modification for C1 lateral screw insertion that incorporates cannulated-navigated screw system with intra-operative 3D imaging. METHODS: A single-center single surgeon database was reviewed to identify all patients who underwent placement of C1 lateral mass screw insertion using the novel technique modification described below, on 2020. This cohort was retrospectively analyzed and compared with a cohort of patients who were operated on by the same surgeon with non-cannulated, navigated screws with intra-operative 3D imaging (O-arm, Medtronic, USA) between 2011 and 2019. Following navigated starting hole and drilling of the C1 lateral mass, a blunt guide-wire is used to palpate the hole and cannulated screw is advanced to the correct position over the wire. After initial purchase, a navigated screw driver is used for final screw depth position. RESULTS: Twelve C1 lateral mass screws were inserted in six patients using this novel cannulated-navigated screw placement technique and compared to 24 patients operated using navigated non-cannulated screws. Minimal Estimated Blood Loss (EBL) was recorded in five of six cases undergoing the novel cannulated navigated placement of C1 lateral mass screws. Comparison to non-cannulated cohort demonstrated an EBL of 83CC vs. 354CC (Not significant). Mean surgery time was 97min and 118min for the cannulated-navigated and navigated only procedures (p = 0.03, statistically significant) respectively. In the current cohort, all screws were rated in optimal position and no repositioning procedures were performed. CONCLUSION: The new method presented allows for faster and possibly safer and more accurate C1 lateral mass screw insertion.

Post-laminectomy Dorsal Cord Migration Resulting in Immediate Neurologic Deterioration during Ventral Meningioma Resection: Proposed Mechanism of Injury and Prevention Technique.

BACKGROUND: Ventral thoracic meningiomas may pose a technical challenge owing to a limited surgical corridor and the presence of long-standing ventral cord compression. Unopposed dorsal spinal cord migration may occur following a laminectomy resulting in immediate neurologic injury. We discuss the possible mechanism underlying such a phenomenon, suggesting alternative approach to prevent neurologic injury. METHODS: Two patients operated on for ventral thoracic meningioma and sustained neurologic compromise were retrospectively evaluated. Image editing software was used for 3D modeling to simulate the possible underlying mechanism of injury. Cases where ventral thoracic meningiomas were approached via unilateral hemilaminectomy, performed in 2020, were retrospectively analyzed and compared with the laminectomy approach cohort. RESULTS: Two patients sustained postoperative neurologic function decline following resection of ventral thoracic meningioma via the laminectomy approach. Both exhibited permanent abolishment of transcranial motor evoked potentials (MEPs) following laminectomy. Based on the extrapolated 3D models for these two cases, dorsal cord migration was postulated as the cause for the acute neurologic compromise. CONCLUSION: Laminectomy for resection of thoracic ventral meningioma may lead in some cases to dorsal cord migration resulting in grave neurologic deterioration. Unilateral approach to these tumors restricts the dorsal migration and may mitigate neurologic outcomes.

Post-operative dysphagia following ventral cervical approach: complication or side-effect? Retrospective analysis and review of the literature.

OBJECTIVE: To ameliorate the clinical decision-making process when debating between a ventral or dorsal cervical approach by elucidating whether post-operative dysphagia be regarded as a complication or a transient side effect. METHODS: A literature review of studies comparing complication rates following ventral and dorsal cervical approaches was performed. A stratified complication rate excluding dysphagia was calculated and discussed. A retrospective cohort of patients operated for degenerative cervical myelopathy in a single institution comprising 665 patients was utilized to analyze complication rates using a uniform definition for dysphagia. RESULTS: Both the ventral and the dorsal approach groups exhibited comparable neurological improvement rates. Since transient dysphagia was not considered a complication, the dorsal approach was associated with higher level of overall complications. CONCLUSIONS AND RELEVANCE: Inconsistencies in the definition of dysphagia following ventral cervical surgery impedes the interpretation of trials comparing dorsal and ventral complication rates. A uniform definition for complications and side effects may enhance the validity of medical trials.

Short-term post-operative complications in 207 patients with multi-level degenerative cervical myelopathy: the effect of surgical approach.

INTRODUCTION: Degenerative cervical myelopathy (DCM) is a common condition often treated by surgical decompression and fusion. The objective of this paper was to compare short-term post-operative complication rates of patients with multi-level DCM treated with decompression and fusion using either an anterior or a posterior cervical approach. MATERIAL AND METHODS: A retrospective evaluation of patients' charts, imaging studies and operative reports of patients operated for multilevel subaxial DCM from 2011 to 2016 at a single institution was performed. Patients who were operated upon for the treatment of three stenosed spinal levels or above and who underwent anterior cervical discectomy and fusion, or anterior cervical corpectomy and fusion, or posterior cervical laminectomy and fusion, were included. Short-term post-operative complications were compared between the anterior and posterior approaches. RESULTS: Overall, 207 patients were included in this study. 156 were operated via an anterior approach and 51 via a posterior approach. The mean number of treated levels was 3.4 and 4.3 for the anterior and posterior approach groups, respectively (p < 0.001). In the posterior approach group, the proportion of stenosed spinal levels within all operated levels was significantly lower than in the anterior approach group (p = 0.025). Early post-operative neurological status change was favourable for both groups. Deep wound infection rate was significantly higher in the posterior approach group (7.8% vs. none; p = 0.001). CONCLUSIONS: Posterior cervical laminectomy and fusion is significantly associated with an increased rate of deep wound infection and wound revision surgery compared to the anterior approach. We recommend the anterior approach as the valid option in treating multi-level DCM.

MRI blind zone: A proposed novel index for spinal implants artifacts.

BACKGROUND: To advocate the formulation of a new index termed MRI Blind Zone, designated to predict the dimensions of the magnetic resonance metallic artifact caused by specific spinal implants. The index may also specify the obscured organs of interest. METHODS: A retrospective evaluation of post-operative MR images of patients operated for spinal instrumentation with various implants from different materials, in our institution, was performed. The MRI blind zone was described for each product, and the related obscured region of interest was discussed. A proposed 3D model was created as an example for suggested future reporting by the implants' industry. RESULTS: Seven implant types are presented. The post-operative MR artifacts were detailed, and the clinical implications were discussed. Material type, processing methods and individual anatomical traits have a dramatic effect on the MRI blind zone and the obscured regions. CONCLUSION: MRI artifact is multifactorial and is influenced in part by the implant's shape, size, material and processing method. Individual products affect post-operative MR artifacts to different extents, and may carry clinical implications when post-operative imaging is required. A standardized index displaying the predicted post-operative artifact is warranted. For the manufacturers to accurately report the data to the surgeons, a parametric standardization should be performed. MRI blind zone index will allow surgeons to compare between different implants efficiently, and improve the informed decision-making process of implant selection.

Neurological event prediction for patients with symptomatic cerebral cavernous malformation: the BLED2 score.

OBJECTIVE: Retrospective patient cohort studies have identified risk factors associated with recurrent focal neurological events in patients with symptomatic cerebral cavernous malformations (CCMs). Using a prospectively maintained database of patients with CCMs, this study identified key risk factors for recurrent neurological events in patients with symptomatic CCM. A simple scoring system and risk stratification calculator was then created to predict future neurological events in patients with symptomatic CCMs. METHODS: This was a dual-center, prospectively acquired, retrospectively analyzed cohort study. Adult patients who presented with symptomatic CCMs causing focal neurological deficits or seizures were uniformly treated and clinically followed from the time of diagnosis onward. Baseline variables included age, sex, history of intracerebral hemorrhage, lesion multiplicity, location, eloquence, size, number of past neurological events, and duration since last event. Stepwise multivariable Cox regression was used to derive independent predictors of recurrent neurological events, and predictive accuracy was assessed. A scoring system based on the relative magnitude of each risk factor was devised, and Kaplan-Meier curve analysis was used to compare event-free survival among patients with different score values. Subsequently, 1-, 2-, and 5-year neurological event rates were calculated for every score value on the basis of the final model. RESULTS: In total, 126 (47%) of 270 patients met the inclusion criteria. During the mean (interquartile range) follow-up of 54.4 (12-66) months, 55 patients (44%) experienced recurrent neurological events. Multivariable analysis yielded 4 risk factors: bleeding at presentation (HR 1.92, p = 0.048), large size ≥ 12 mm (HR 2.06, p = 0.016), eloquent location (HR 3.01, p = 0.013), and duration ≤ 1 year since last event (HR 9.28, p = 0.002). The model achieved an optimism-corrected c-statistic of 0.7209. All factors were assigned 1 point, except duration from last event which was assigned 2 points. The acronym BLED2 summarizes the scoring system. The 1-, 2-, and 5-year risks of a recurrent neurological event ranged from 0.6%, 1.2%, and 2.3%, respectively, for patients with a BLED2 score of 0, to 48%, 74%, and 93%, respectively, for patients with a BLED2 score of 5. CONCLUSIONS: The BLED2 risk score predicts prospective neurological events in symptomatic CCM patients.

[RESIDENT DUTY HOUR RESTRICTIONS IN NEUROSURGERY: WHAT CAN WE LEARN IN ISRAEL FROM THE NORTH AMERICAN AND EUROPEAN EXPERIENCE?]

INTRODUCTION: The impact of the 2003 Duty Hour Restriction mandate in the United States and the Working Time Directive in Europe on neurosurgery training has been immense. This report reviews the current literature studying the implications of these regulations on the quality of neurosurgery training as well as on patient safety. In the majority of publications, limited working hours has resulted in increased post-operative complication rates and diminished in-training surgical experience. In Europe, the reduction in surgical experience had led to a decreased sense of confidence in operating independently by the end of training. This review demonstrates the importance of tailoring a specific framework for the individual needs of each residency program, and recommends avoiding the application of universal regulations on all medical professions and training.

Delayed variations in the diagnostic accuracy of intraoperative neuromonitoring in the resection of intramedullary spinal cord tumors.

OBJECTIVE: The use of intraoperative neuromonitoring (IONM) has become an imperative adjunct to the resection of intramedullary spinal cord tumors (IMSCTs). While the diagnostic utility of IONM during the immediate postoperative period has been previously studied, its long-term diagnostic accuracy has seldom been thoroughly assessed. The aim of this study was to evaluate long-term variations in the diagnostic accuracy of transcranial motor evoked potentials (tcMEPs), somatosensory evoked potentials (SSEPs), and D-wave recordings during IMSCT excision. METHODS: The authors performed a retrospective evaluation of imaging studies, patient charts, operative reports, and IONM recordings of patients who were operated on for gross-total or subtotal resection of IMSCTs at a single institution between 2012 and 2018. Variations in the specificity, sensitivity, positive predictive value (PPV), and negative predictive value (NPV) for postoperative functional outcome (McCormick Scale) were analyzed at postoperative day 1 (POD1), 6 weeks postoperatively (PO-6 weeks), and at the latest follow-up. RESULTS: Overall, 28 patients were included. The mean length of follow-up was 19 ± 23.4 months. Persistent motor attenuations occurred in 71.4% of the cohort. MEP was the most sensitive modality (78.6%, 87.5%, and 85.7% sensitivity at POD1, PO-6 weeks, and last follow-up, respectively). The specificity of the D-wave was the most consistent over time (100%, 83.35%, and 90% specificity at the aforementioned time points). The PPV of motor recordings decreased over time (58% vs 33% and 100% vs 0 for tcMEP and D-wave at POD1 and last follow-up, respectively), while their NPV consistently increased (67% vs 89% and 70% vs 100% for tcMEP and D-wave at POD1 and last follow-up, respectively). CONCLUSIONS: The diagnostic accuracy of IONM in the resection of IMSCTs varies during the postoperative period. The decrease in the PPV of motor recordings over time suggests that this method is more predictive of short-term rather than long-term neurological deficits. The increasing NPV of motor recordings indicates a higher diagnostic accuracy in the identification of patients who preserve neurological function, albeit with an increased proportion of false-negative alarms for the immediate postoperative period. These variations should be considered in the surgical decision-making process when weighing the risk of resection-associated neurological injury against the implications of incomplete tumor resection.

Minimally Invasive Intracerebral Hematoma Evacuation Using a Novel Cost-Effective Tubular Retractor: Single-Center Experience.

BACKGROUND: Spontaneous intracerebral hematoma (ICH) is a common disease with a dismal overall prognosis. Recent development of minimally invasive ICH evacuation techniques has shown promising results. Commercially available tubular retractors are commonly used for minimally invasive ICH evacuation yet are globally unavailable. METHODS: A novel U.S. $7 cost-effective, off-the-shelf, atraumatic tubular retractor for minimally invasive intracranial surgery is described. Patients with acute spontaneous ICH underwent microsurgical tubular retractor-assisted minimally invasive ICH evacuation using the novel retractor. Patient outcome was retrospectively analyzed and compared with open surgery and with commercial tubular retractors. RESULTS: Ten adult patients with spontaneous supratentorial ICH and median preoperative Glasgow Coma Scale score of 10 were included. ICH involved the frontal lobe, parietal lobe, occipitotemporal region, and solely basal ganglia in 3, 3, 2, and 2 patients, respectively. Mean preoperative ICH volume was 80 mL. Mean residual hematoma volume was 8.7 mL and mean volumetric hematoma reduction was 91% (median, 94%). Seven patients (70%) underwent >90% volumetric hematoma reduction. The total median length of hospitalization was 26 days. On discharge, the median Glasgow Coma Scale score was 12.5 (mean, 11.7). Thirty to 90 days' follow-up data were available for 9 patients (90%). The mean follow-up modified Rankin Scale score was 3.7 and 5 patients (56%) had a modified Rankin Scale score of 3. CONCLUSIONS: The novel cost-effective tubular retractor and microsurgical technique offer a safe and effective method for minimally invasive ICH evacuation. Cost-effective tubular retractors may continue to present a valid alternative to commercial tubular retractors.

Encephaloduroarteriosynangiosis with Dural Inversion for Moyamoya Disease in a Pediatric and Adult Population-a Single-Center 20-Year Experience.

BACKGROUND: Moyamoya disease refers to a progressive vasostenotic or vaso-occlusive disease that puts patients at risk for ischemic and/or hemorrhagic events. Surgical revascularization procedures aim to restore cerebral blood flow to mitigate stroke risk and functional decline. Direct and indirect bypass procedures have been proposed. Encephaloduroarteriosynangiosis (EDAS) with dural inversion is a well-accepted indirect procedure. METHODS: Patients with moyamoya disease undergoing EDAS with dural inversion between 2000 and 2019 were retrospectively reviewed. Clinical data including short-term and long-term outcome were measured using the modified Rankin Scale. Patient satisfaction was assessed in patients with a minimum of 3 years of clinical follow-up. RESULTS: Over a 20-year period, 54 patients underwent 88 EDAS with dural inversion procedures. Most patients underwent bilateral surgery (34/54 patients, 63.0%). Median age at surgery was 19 years (range, 1-63 years) with a median follow-up of 6 years (range, 1-20 years). Periprocedural complications occurred in 4 of 54 patients (7.4%). Periprocedural infarction occurred in 3 of 88 operations (3.4%). Functional outcome at 90 days was favorable (modified Rankin Scale score 0-2) in 92.6% of cases. On long-term follow-up, 3 patients experienced ischemic infarction (5.6%), and 1 patient (1.9%) experienced hemorrhagic infarction. Patients' overall satisfaction with the surgical procedure at last follow-up was determined in 36 of 45 patients with at least 3 years of follow-up (response rate 80.0%). Median satisfaction was very good (score 5; range, 3-5). CONCLUSIONS: EDAS with dural inversion is a safe and effective indirect revascularization procedure for pediatric and adult moyamoya disease that is associated with favorable long-term outcomes and high patient satisfaction.

Surgical Management of Failed Endovascular Treatment for Spinal Dural Arteriovenous Fistulas.

BACKGROUND: Spinal dural arteriovenous fistulas (SDAVFs) are rare vascular malformations. Digital subtraction angiography is the modality of choice to demonstrate the malformation before endovascular embolization or open surgical repair. Angiographically occult SDAVFs have been previously reported. Surgical considerations in SDAVFs with misleading angiography findings have not yet been assessed. METHODS: A retrospective evaluation of charts and imaging files of patients operated on for SDAVF in 2018-2019 at a single institution was performed. All patients were referred to surgery following failure of endovascular embolization or owing to clinical and radiographic deterioration in the presence of an angiographically occult lesion. Cases were comprehensively reviewed and evaluated for surgical considerations in these lesions. RESULTS: This case series included 4 cases. Two patients underwent embolization before surgical repair but continued to deteriorate neurologically, and 2 patients had a failed embolization attempt owing to a torturous vascular network. In all 4 patients, exploration was successful, yielding either improvement or stabilization of neurological status. Indocyanine green injection for microscopically integrated fluorescent angiography contributed to the identification of the supplying vessels and confirmed the SDAVF closure. CONCLUSIONS: SDAVFs should be treated promptly after diagnosis. In cases with high suspicion for SDAVF with occult or misleading angiography findings, spinal exploration should be pursued with no delay. Indocyanine green-assisted microscopic angiography may contribute to exploratory spine surgery for SDAVF closure.

One-step insertion of navigated pedicle screws in minimally invasive transforaminal lumbar interbody fusion (MITLIF): preliminary results of a novel technique.

OBJECTIVE: To describe a novel technique modification and evaluate initial results of pedicle screw insertion in minimally invasive transforaminal lumbar interbody fusion (MITLIF), using self-drilling self-tapping one-step screws. PATIENTS AND METHODS: All patients who were operated for MITLIF using the one-step technique over the last 6 months period at a single institute, were retrospectively identified. The surgical technique is described and depicted. Outcome evaluation was performed, including screw misplacement, screw insertion time, and post-operative complications. RESULTS: We describe a novel technique modification in which self-drilling self-tapping navigated screws incorporate an embedded K-wire that enables a one-step insertion which obviates the need for instrument exchange. The first four patients in whom this technique was implemented were included (mean age was 55). All patients had been previously operated at the fused level. The mean surgical duration was 142 minutes and the calculated mean screw insertion time was 8.2 minutes. The mean estimated blood loss was 66 cc. An intraoperative 3D scan demonstrated no screw pedicle breach. There were no neurological complications or wound healing disturbances. The clinical course was uneventful for all patients. CONCLUSION: To our knowledge, the use of one-step navigation-assisted self-drilling self-tapping pedicle screws with an embedded K-wire has not been previously described. Our initial experience with this novel technique modification was efficient and safe. Navigated surgery allows for newer and safer techniques to be incorporated into the surgeon's toolbox. Further studies should be performed to thoroughly evaluate this technique.

Minimally Invasive Spine Surgery: The Learning Curve of a Single Surgeon.

STUDY DESIGN: Retrospective cohort study. OBJECTIVES: The learning curve associated with the implementation of minimally invasive spinal surgery (MIS) has been the center of attention in numerous publications. So far, these studies referred to a single MIS procedure. In our view, minimally invasive surgical skills are acquired simultaneously through a variety of procedures that share common features. The aim of this study was to analyze the skills progression of a single surgeon implementing diverse minimally invasive techniques. METHODS: We retrospectively collected all patients who underwent spinal surgery for thoracic or lumbar pathology by a single surgeon between 2012 and 2015 at a single institute. Both minimally invasive as well as open surgical techniques were analyzed; these groups were compared on the basis of surgical indications and outcomes. Skills progression analysis in reference to minimally invasive technique was performed. RESULTS: A total of 230 patients met the inclusion criteria for this study. MIS group included higher percentage of lumbar discectomy and the open-surgery group included higher percentage of tumor resection surgery. Learning curve evaluation demonstrated increased surgical complexity, evaluated by number of levels treated, over the 4-year period, which corresponded with decreased complication rates. DISCUSSION: A gradual increase in surgical complexity over 4 years, together with careful patient selection, enables the surgeon to maintain the rate of complication within acceptable limits. The main challenge facing the MIS community is constructing an education program for MIS surgeons in order to reduce the learning curve-induced complications. CONCLUSION: Advancement of educational aids for MIS surgical skill improvement, including spine models, virtual and augmented reality aids and surgical simulators may reduce the learning curve of spine surgeons.

Integrity of the tectorial membrane is a favorable prognostic factor in atlanto-occipital dislocation.

Objective: Atlanto-occipital dislocation is usually considered to be a fatal injury or one that leaves the victim with serious neurological deficits. The aim of this study is to illustrate a novel positive prognostic factor for atlanto-occipital dislocation, based on cervical MRI studies of patients who suffered this injury.Methods: Over the course of the past year, the authors have treated three consecutive patients with atlanto-occipital dislocation who attained an excellent clinical outcome. We retrospectively evaluated clinical, surgical and radiographic parameters in search of a common denominator to explain the excellent outcome of these patients.Results: All patients presented with severe polytrauma that required urgent surgical intervention including two laparotomies and a thoracotomy. The patients were subsequently treated with an occipitocervical fusion. No patient developed neurological deficits on long-term follow-up. The cervical MRI studies of all patients were notable for a having a preserved tectorial membrane, while other primary stabilizers of the craniocervical junction such as the apical, alar and cruciate ligaments were shown to be severely disrupted. We consider this anatomical distinction to account for their benign clinical course.Conclusion: A preserved tectorial membrane appears to be an important favorable prognostic factor in atlanto-occipital dislocation and may serve to mitigate neurological outcome in such injuries. To determine the integrity of the ligament and consequently affect clinical management, expeditious MRI of the cranio-cervical junction should be considered routinely in such injuries in addition to cervical CT scans.

Brain Metastases from Ovarian Carcinoma: An Evaluation of Prognostic Factors and Treatment.

AIMS AND OBJECTIVES: To review a series of patients with brain metastases from ovarian cancer at a single institution. To describe treatment modalities, their outcomes and to determine prognostic factors. PATIENTS AND METHODS: Between January 1995 and December 2014, 25 patients with ovarian cancer brain metastases were treated at The Sheba Medical Center. The medical records were retrospectively reviewed to collect demographic, clinical, and imaging data as well as the information on the treatment modalities used and their outcomes. RESULTS: Mean patient age at the time of brain metastasis diagnosis was 62.7 years. The median interval between the diagnosis of primary cancer and brain metastasis was 42.3 months. Neurologic deficits, headache, and seizure were the most common symptoms. The brain was the only site of metastasis in 20% of the patients. Active ovarian cancer at the time of diagnosis of brain metastasis was observed in half of the patients with systemic disease. Multiple brain metastases were observed in 25% of the patients. We treated 11 patients with surgery plus radiation therapy protocols in various orders: surgery followed by complementary whole-brain radiation therapy (WBRT), surgery followed by stereotactic radiosurgery (SRS), and surgery followed by WBRT and then by adjuvant SRS. Five patients underwent surgery alone and nine patients were treated with radiation alone (WBRT, SRS, or both). Univariate analysis for predictors of survival demonstrated that age above 62.7 years at the time of central nervous system involvement was a significant risk factor and leptomeningeal disease was a poor prognostic factor in reference to supra-tentorial lesions. Multivariate analysis for predictors of survival, however, showed that multiple brain lesions (>4) were a poor prognostic factor, and multivariate analysis of the time to progression revealed that combined treatments of surgery and radiation resulted in longer median periods of progression-free survival than each modality alone. CONCLUSION: We conclude that the only significant predictors of survival or progression-free survival in our cohort were the number of brain metastases and the treatment modality.

Predicting and reducing cranioplasty infections by clinical, radiographic and operative parameters - A historical cohort study.

Cranioplasty is a relatively straightforward and common procedure, yet it carries a substantial rate of infection that causes major morbidity and mortality. The authors' objective was to assess the effect of various variables on the risk of developing post-cranioplasty infections, and to enable the prediction and reduction of its incidence, contributing to an improved patient-selection. The medical records, microbiologic cultures, imaging studies and operative reports of patients who have undergone cranioplasty between the years 2008-2014 at Sheba Medical Center, a tertiary care teaching hospital in Tel-Hashomer, Israel, were reviewed and evaluated for potential predictive factors of infection. Cox regression was applied for uni- as well as multi-variate analyses, and a Kaplan-Meier curve and Log-Rank test were used to describe the association between neurological deficit prior to operation and occurrence of infection. Eighty-eight patients who had undergone cranioplasties using autologous as well as various artificial materials were included in the study. The overall rate of infection was 13.6%; median time to infection was 30.5 days (interquartile range: 17.35-43.5). Pre-operative degree of neurological disability was the strongest predictor for infection in both uni- and multi-variate analyses (Hazard ratio [HR]=18.9, 95% confidence interval [CI]: 1.9-187 p=0.014). Patients admitted due to trauma (HR=7.04 CI: 0.9-54.6, p=0.062) and autologous graft material (HR=2.88, 95% CI: 0.92-9.09, p=0.07) were associated with a trend toward a higher risk for infection. In conclusion, careful patient selection is a key concept in avoiding harmful post-cranioplasty infections. Modified Rankin Score yields a well-established tool that predicts the risk of infection.