Dorsal column mapping in resection of intramedullary spinal cord tumors: a prospective comparison of two methods and neurological follow-up.

PURPOSE: In surgery for intramedullary spinal cord tumors (imSCT), distortion of the anatomy challenges the visual identification of dorsal columns (DC) for midline myelotomy. Dorsal column mapping (DCM) and spinal cord stimulation (SCS) can identify DC neurophysiologically. We compare application and feasibility of both methods. METHODS: Patients with surgically treated imSCT were prospectively included between 04/2017 and 06/2019. The anatomical midline (AM) was marked. SSEPs at the DC after stimulation of tibial/median nerve with an 8-channel DCM electrode and cortical SSEP phase reversal at C3/C4 after SCS using a bipolar concentric probe were recorded. Procedural and technical aspects were compared. Standardized neurological examinations were performed preoperatively, 1 week postoperatively and after more than 12 months. RESULTS: The DCM electrode detected the midline in 9/13 patients with handling limitations in the remaining patients. SCS was applicable in all patients with determination of the midline in 9/13. If both recordings could be acquired (6/13), concordance was 100%. If baseline SSEPs were poor, both methods were limited. SCS was less time-consuming (p = 0.001), cheaper, and easier to handle. In 92% of cases, the AM and neurophysiologic midlines were concordant. After myelotomy, 3 patients experienced > 50% reduction in amplitude of SSEPs. Despite early postoperative worsening of DC function, long-term follow-up showed significant recovery and improvement in quality of life. CONCLUSION: DCM and SCS may help confirm and correct the AM for myelotomy in imSCT, leading to a favorable long-term neurological outcome in this cohort. SCS evolved to be superior concerning applicability, cost-effectiveness, and time expenditure.

Intraoperative ultrasonography in laminectomy for degenerative cervical spondylotic myelopathy: a clinical and radiological evaluation.

BACKGROUND: The incidence of cervical myelopathy due to spinal stenosis is constantly growing in an aging population. Especially in multisegmental disease, dorsal laminectomy is the intervention of choice. Intraoperative imaging with ultrasound might provide additional information about extent and sufficiency of spinal cord decompression. METHODS: In this prospective study, the width of the subarachnoid space was systematically measured by intraoperative ultrasound at predefined sites at the cranial and caudal edge of decompression in axial and sagittal reconstruction. These data were compared with corresponding sites on postoperative T2-weighted MRI imaging. In addition, the functional outcome was assessed by modified Japanese Orthopaedic Association (mJOA) score. A historical patient cohort treated without ultrasound-guided laminectomy served as control group. RESULTS: Altogether, 29 patients were included. According to mJOA score at last follow-up, 7/29 patients reported stable symptoms and 21/29 patients showed a substantial benefit with no or minor residual neurological deficits. One patient suffered from a new C5 palsy. Intraoperative ultrasound-guided posterior decompression provided excellent overview in all cases. Measurement of the width of the subarachnoid space acquired by intraoperative ultrasound and postoperative MRI images showed a very high correlation, especially at the cranial level (p < 0.001, r = 0.880). Bland-Altman analysis showed that most patients were within the 1.96 × SD limits of agreement throughout all measurements. No ultrasound procedure-related complications were observed. Compared to a historical cohort of 27 patients, no significant differences were found regarding functional outcome (p = 0.711). CONCLUSION: Intraoperative sonography visualises the surgically achieved restoration of the subarachnoid space in good correlation with postoperative MRI and might serve as a fast, precise and reliable tool for intraoperative imaging in cervical laminectomy. However, we could not demonstrate a clinical benefit with regard to functional outcome.

Routine intraoperative microbiological smear testing in patients with reoperation after elective degenerative non-instrumented spine surgery-useful or negligible adjunct.

PURPOSE: Surgical site infections (SSI) are a rare but dreaded cause for recurrent symptomatology requiring reoperation after degenerative spine surgery. We here aim to elucidate if routine microbiological smear testing during reoperation might be a useful tool for subsequent patient management. METHODS: We investigated clinical, laboratory/imaging characteristics, and outcome of patients undergoing reoperation in the previously affected segment during follow-up after elective degenerative non-instrumented spine surgery. Microbiological cultures via multiple intraoperative smear tests of the superficial/deep wound layers were routinely performed and correlated with clinical/imaging/laboratory/surgical signs for SSI and outcome. RESULTS: From altogether 2552 patients with degenerative spine surgery in 2014-2019, a total of 62 patients (m:f = 1.6:1, median 69 years) underwent same-level reoperation due to recurrent symptomatology (mean ∆-time:17 ± 36 months) with a predominance of the lumbar spine (90%). In 9 patients with imaging/laboratory suspicious for SSI, microbiological culturing of intraoperative smear testing revealed conclusive pathogen growth in 89% (100% with additional PCR analysis); the predominant pathogen was Staphylococcus aureus with detection mainly in the deep wound layers. In contrast, in 53 patients without clinical/imaging/laboratory/intraoperative signs for SSI microbiological culturing showed minor pathogen growth in 15% displaying bacterial colonization/contamination of the surgical site. The predominant pathogens in this cohort were Staphylococcus epidermidis and Cutibacterium acnes, and these patients had favorable outcomes when monitored with close surveillance without anti-infective treatment. CONCLUSION: Bacterial colonization/contamination occurs in 15% of patients without signs of infection undergoing same-level reoperation after degenerative spine surgery. These patients can be managed with close surveillance without antibiotic treatment.

Spinal intradural extramedullary arachnoid cysts in adults-operative therapy and clinical outcome.

BACKGROUND: Spinal arachnoid cysts (SAC) are rare mostly idiopathic intradural lesions with compression of the spinal cord and clinical signs of radiculo- and/or myelopathy. We retrospectively analyzed radiological and clinical characteristics of patients with surgical treatment of SAC including a subgroup evaluation of long-term outcome and QoL. METHOD: Patients with SAC treated between 1993 and 2017 were evaluated. Craniocaudal (c.c.) and anteroposterior (a.p) cyst diameters were measured pre- and post-OP. McCormick and Odom score for myelopathy, general outcome and QoL (SF-36, EORTC-QLQ30) were recorded. RESULTS: A total of 72 patients (female:male = 1.9:1) were analyzed with mean FU of 44.8 ± 60 months (long-term data from 25 patients with FU 78.2 ± 63.9 months). All had surgery due to solitary cysts: 10 cervical (13.9%), 45 thoracic (62.5%), and 17 lumbosacral (23.6%), the majority (79.2%) located dorsally. Main symptoms were gait disturbance (80%), dysesthesia (64%) and paresis (80%). Patients had (hemi-)laminectomy with cyst fenestration in 48 (66.7%) and complete resection in 18 cases (25.0%). Four cases (5.5%) were treated by cystoperitoneal shunt, 2 by marsupialization (2.8%). In total, 11 revisions were necessary in 9/72 (12.5%) patients (one patient underwent 3 revisions). Two patients were reoperated for wound revision/epidural hematoma (each n = 1). Seven patients needed additional cyst wall resection after 1.5-31.0 months due to insufficient cyst shrinking and persistent clinical symptoms after first surgery; most of the cysts were multiple septated and of post-hemorrhagic origin. The mean c.c. size decreased from 5.2 ± 3.7 cm pre-OP to 2.7 ± 3.9 cm (p < 0.05); the a.p. diameter decreased from 1.0 ± 0.5 cm to 0.3 ± 0.3 cm (p < 0.0001) without significant differences between fenestration and resection. McCormick and Odom scores revealed improved symptoms, particularly of gait disturbance, sensory deficits, and general performance. Long-term FU displayed satisfying QoL performance without differences of fenestration or resection. CONCLUSION: SAC mostly affect women and are predominantly located in the thoracic spine, becoming apparent with clinical myelopathy. For cysts without intracystic septae and compartments, both fenestration and resection of the cyst wall provided significant reduction of cyst size and clinical improvement.

Surgery of degenerative thoracic spinal stenosis-long-term outcome with quality-of-life after posterior decompression via an uni- or bilateral approach.

BACKGROUND: The rate of degenerative thoracic spinal stenosis (TSS) as underlying pathology for myelopathy is not precisely known, and larger case series are only available for the Asian region. We present one of the largest European series to evaluate rate and clinical outcome after dorsal decompression via a uni- or bilateral approach. METHOD: We investigated patients' characteristics, imaging/surgical parameters, and outcomes with quality-of-life (QOL) in all patients who underwent surgical treatment for TSS between 2013 and 2018 in a university neurosurgical clinic. RESULTS: From 645 patients with surgery for degenerative spondylotic myelopathy within 6 years, 28 patients (4.3%) suffered from TSS. Median age was 70.4 years with a slight predominance of the female sex (m:f = 1:1.3). The most frequent symptoms (mean duration 7.6 months) were ataxia (61%) and sensory changes (50%). The stenoses (median Naganawa score 3) mostly resulted from a combined osseous/ligamentous hypertrophy and disc prolapse, the majority located below Th8 (75%). Nineteen patients with lateralized compression underwent bilateral decompression via a unilateral approach (fenestration/hemilaminectomy with "undercutting" procedure), and 9 patients with circular pathology underwent bilateral-approached decompression (laminectomy). There were no significant differences of patients' characteristics, blood loss, operation time, and in-patient stay between both surgical groups. Independent from the mode of surgery, the spinal canal was significantly (p < 0.001) widened (median Naganawa score 0), and pain (p = 0.04), myelopathy (mJOA score p = 0.01), and QOL (Oswestry Disability Index, p = 0.03; SF-36-MCS, p = 0.01) were significantly improved at long-term follow-up (mean 35.1 months). CONCLUSIONS: Non-tumorous myelopathy is caused in about 4% of patients by TSS and can be effectively treated by surgical decompression via both a uni- or bilateral approach.

Intraspinal epidermoid and dermoid cysts-tumor resection with multimodal intraoperative neurophysiological monitoring and long-term outcome.

BACKGROUND: Intraspinal epidermoid/dermoid cysts are very rare, benign tumors arising from pathological displacement of epidermal cells into the spinal canal. Literature data about the long-term outcome after microsurgical resection with multimodal intraoperative neurophysiological monitoring (IONM) are lacking. We analyzed one of the largest case series with special regard to intraoperative characteristics and long-term outcome after IONM-aided surgery. METHOD: All 12 patients (m:f = 1.4:1) who underwent microsurgical tumor resection with multimodal IONM for intraspinal epidermoid/dermoid tumors between 1998 and 2019 in our university hospital were included. We retrospectively investigated the patients' characteristics, imaging/surgical parameters, and postoperative long-term outcomes. RESULTS: Symptomatic tumor manifestation was seen during adulthood in 4 patients (median age 33.0 years) and during childhood in 8 patients (median age 4.3 years). Spinal dysraphism was the most often comorbidity (75%). The most frequent symptoms at diagnosis were spastic pareses (75%), ataxia (58%), and vegetative disorders (42%). Tumors were most often lumbosacral (L1-L5 42%, L5-S3 50%) and intradural-extramedullary (92%). For microsurgical resection, IONM with EMG, SSEPs, and TcMEPs of the limbs and pudendal nerve/anal sphincter was always applied and feasible; intraoperative corrective actions were initiated in three cases due to transient IONM deterioration. None of the patients showed a postoperative deterioration of the neurological status with a gross total resection rate of 92%. Pain situation, McCormick grade, and mJOA Score were improved at long-term follow-up (median 4.8 years). CONCLUSIONS: IONM-aided resection of intraspinal epidermoid/dermoid tumors is feasible both in adult and pediatric cases and enables a satisfying clinical and surgical outcome.

Indication and technical implementation of the intraoperative neurophysiological monitoring during spine surgeries-a transnational survey in the German-speaking countries.

BACKGROUND: Intraoperative neurophysiological monitoring is widely used in spine surgery (sIONM). But guidelines are lacking and its use is mainly driven by individual surgeons' preferences and medicolegal advisements. To gain an overview over the current status of sIONM implementation, we conducted a transnational survey in the German-speaking countries. METHODS: We developed a Web interface-based survey assessing prevalence, indication, technical implementation, and general satisfaction regarding sIONM in German, Austrian, and Swiss spine centers. The electronic survey was performed between November 2017 and April 2018, including both neurosurgical and orthopedic spine centers. RESULTS: A total of 463 German, 60 Austrian, and 52 Swiss spine centers were contacted with participation rates of 64.1% (Germany), 68.3% (Austria), and 55.8% (Switzerland). Some 75.9% participating neurosurgical spine centers and only 14.7% of the orthopedic spine centers applied sIONM. Motor- and somatosensory-evoked potentials (93.7% and 94.3%, respectively) were the most widely available modalities, followed by direct wave (D wave; 66.5%). Whereas sIONM utilization was low in spine surgeries for degenerative, traumatic, and extradural tumor diseases, it was high for scoliosis and intradural tumor surgeries. Overall, the general satisfaction within the institutional setting regarding technical skills, staff, performance, and reliability of sIONM was rated as "high" by more than three-quarters of the centers. However, shortage of skilled staff was claimed to be a negative factor by 41.1% of the centers and reimbursement was considered to be insufficient by 83.5%. CONCLUSIONS: sIONM availability was high in neurosurgical but low in orthopedic spine centers. Main modalities were motor/somatosensory-evoked potentials and main indications were scoliosis and intradural spinal tumor surgeries. A more frequent sIONM use, however, was mainly limited by the shortage of skilled staff and restricted reimbursement.

Visualization of Liliequist's membrane prior to endoscopic third ventriculostomy.

PURPOSE: Endoscopic third ventriculostomy (ETV) is an effective treatment in patients with obstructive hydrocephalus caused by aqueductal stenosis. Operative failure may occur if an unnoticed membrane below the floor of the third ventricle is present, such as Liliequist's membrane (LM). To analyze how often LM can be visualized by high-resolution heavily T2-weighted 3D-MRI prior to ETV, and to find out potential reasons for diagnostic failure. MATERIALS AND METHODS: Preoperative 3D-MR images of 37 consecutive patients (19 female, median 42 years) were retrospectively analyzed. Visualization of three LM segments (sellar, diencephalic, mesencephalic), dimensions of the space below the third ventricle, and extent of hydrocephalus were measured. Image quality was scored (score 1[poor] to 3[excellent]). Preoperative imaging findings were compared with intraoperative findings. RESULTS: Patients were subdivided into group 1 (no segment of LM identified, n = 18), and group 2 (at least one segment of LM was identified, n = 19). The sellar segment of LM was most often positively identified (10 out of 19 cases). The mean distance between the pons and the sella/clivus was significantly shorter in group 1 than in group 2 (3.7 vs. 6.2 mm; p < 0.01). Other variables, such as the distance between tip of the pons and the mamillary bodies as well as the image quality, were not significantly different between both groups. Intraoperatively, LM was present in 78 % of group 2 patients, and in 28 % of group 1 patients, respectively (p < 0.03). CONCLUSIONS: LM can be detected in about half of patients prior to ETV. Reduced PSD influences visualization of LM.

Microsurgical fenestration of idiopathic intramedullary cysts in adult patients.

PURPOSE: The aim of this study is to describe the findings in one of the largest series of microsurgically treated intramedullary cysts investigated by magnetic resonance imaging (MRI), focusing on the peri- and intraoperative setup including detailed neurological and radiological outcome analyses. METHODS: Retrospective analysis of patients with intramedullary cyst who had undergone microsurgical fenestration at our department between 2006 and 2011. Preoperative three-dimensional constructive interference of steady-state MRI was conducted to optimize surgical planning. Intraoperative electrophysiological monitoring included motor-evoked potentials, somatosensory-evoked potentials, and electromyogram. Clinical outcome as well as pre-, postoperative and long-term MRI scans were evaluated. RESULTS: Eight female patients (median age 58.0 years, range 32-72 years) with a median clinical follow-up of 48.0 months (range 2-69 months) were included. Seven cysts were located in the conus medullaris, one in the cervical spine. Overall, 25.0% (2/8) showed complete remission of preoperative symptoms, 62.5% (5/8) improved, and 12.5% (1/8) asymptomatic patients remained unchanged. Pain syndromes (4/4) as well as motor deficits (2/2) improved in all affected patients and bladder dysfunction (3/4) displayed a high tendency for improvement. Postoperative MRI scans showed permanently decreased cyst volumes by ~80%. CONCLUSION: Microsurgical fenestration of intramedullary cysts using preoperative high-resolution imaging and intraoperative electrophysiological monitoring is a safe and effective treatment option for symptomatic patients.

Strong Association of Depression and Anxiety With the Presence of Back Pain While Impact of Spinal Imaging Findings is Limited: Analysis of an MRI Cohort Study.

Development of back pain is multifactorial, and it is not well understood which factors are the main drivers of the disease. We therefore applied a machine-learning approach to an existing large cohort study data set and sought to identify and rank the most important contributors to the presence of back pain amongst the documented parameters of the cohort. Data from 399 participants in the KORA-MRI (Cooperative health research in the region Augsburg-magnetic resonance imaging) (Cooperative Health Research in the Region Augsburg) study was analyzed. The data set included MRI images of the whole body, including the spine, metabolic, sociodemographic, anthropometric, and cardiovascular data. The presence of back pain was one of the documented items in this data set. Applying a machine-learning approach to this preexisting data set, we sought to identify the variables that were most strongly associated with back pain. Mediation analysis was performed to evaluate the underlying mechanisms of the identified associations. We found that depression and anxiety were the 2 most selected predictors for back pain in our model. Additionally, body mass index, spinal canal width and disc generation, medium and heavy physical work as well as cardiovascular factors were among the top 10 most selected predictors. Using mediation analysis, we found that the effects of anxiety and depression on the presence of back pain were mainly direct effects that were not mediated by spinal imaging. In summary, we found that psychological factors were the most important predictors of back pain in our cohort. This supports the notion that back pain should be treated in a personalized multidimensional framework. PERSPECTIVE: This article presents a wholistic approach to the problem of back pain. We found that depression and anxiety were the top predictors of back pain in our cohort. This strengthens the case for a multidimensional treatment approach to back pain, possibly with a special emphasis on psychological factors.

Detethering of a congenital tethered cord in adult patients: an outcome analysis.

BACKGROUND: Tethered spinal cord syndrome (TCS) is characterized by attachment of the spinal cord down toward the tail end of the spine, comprising the danger of myelopathic symptoms. We retrospectively analyzed postoperative neurological outcome in adult patients with congenital TCS with special regard to the extent of resection of concomitant intraspinal lipomas. METHODS: Medical records of 27 adult patients with congenital TCS (both with and without associated spinal lipomas) undergoing microsurgical detethering were systematically analyzed. Neurophysiological monitoring was available and feasible for all cases. Outcome parameters were preoperatively and postoperative neurological status; Wilcoxon rank test was used for statistical analysis. RESULTS: In all patients, complete detethering was achieved. While urinary symptoms remained stable, all patients showed a non-significant tendency towards improvement of sensorimotor deficits. Both, patients with and without spinal lipoma experienced a significant postoperative amelioration of back pain. Patients with lipoma were found to suffer significantly less from radicular pain postoperatively (3/16). Furthermore, patients with a history of pain shorter than 1 year showed a significantly better chance for postoperative relief from back and radicular pain. The extent of lipoma resection had no significant impact on postoperative outcome. CONCLUSIONS: Adult patients with symptomatic TCS profit from detethering, especially regarding relief of lower back and radicular pain. Complete removal of associated spinal lipomas does not seem to be mandatory for achieving a satisfying result.

The projected numbers of degenerative spine disease in Austria from 2017 to 2080: a perspective-based scenario analysis.

BACKGROUND: Spinal surgery has to address the challenge of a dramatic increase of the growing number of older persons. The purpose of the present study was to project the numbers of surgically treated degenerative spine disease (DSD) in Austria from 2017 until 2080 to provide potential future scenarios that the Austrian Health system might have to face. METHODS: Current numbers on demographic information from Austria as well as population projections for 2017-2080 were obtained from Statistics Austria (STAT). A lower/main/upper scenario reflecting low/main/high growth and ageing scenarios deducted from fertility, life expectancy and immigration calculations was used. Information on prevalence of surgically treated DSD was obtained from the Austrian Spine Register. RESULTS: The population in Austria (evaluated in 2017) was 8.78 millions and is estimated to evolve to 7.86/10.0/13.1 millions by 2080. The total number of surgically treated DSD recorded in the Spine Register was 9300 and was estimated to be 9300/11200/13700 in 2080. The number of subjects with surgically treated DSD were expected to increase in the age-strata (main scenario), 100% corresponds to the number in each age and gender stratum: 0-40 years by (male/female) 2%/2%, 40-50 years -7%/-7%, 50-59 years -11%/-9%, 60-69 years 21%/16%, 70-79 years 51%/31%, 80-89 years 211%/129% and 90+years 698%/411%. CONCLUSIONS: Total numbers of subjects with DSD in Austria will increase from 2017 to 2080. The increase will be substantial in those aged 80+ and those aged 90+. The assumptions of this analysis were taken conservatively. Hence, the future socio-economic burden to society might be greater as projected by the study.

Robot-assisted versus navigated transpedicular spine fusion: A comparative study.

BACKGROUND: The aim of this study was to compare the intraoperative and postoperative outcomes between a robot-assisted versus a navigated transpedicular fusion technique. METHODS: This retrospective analysis included patients who underwent transpedicular posterior fusion of the spine due to trauma, pyogenic spondylodiscitis and osteoporosis. Surgery was done either with a robot-assisted or a percutaneous navigated transpedicular fusion technique. The outcome analysis included the duration of surgery, the radiation exposure, the postoperative screw position and complications. RESULTS: A total of 60 patients were operated and 491 screws were analysed. No statistical difference was seen in the applied cumulative effective radiation dose per patient. The radiological assessment revealed a more accurate screw placement with robot assistance. A learning curve could be observed in robot-assisted fusion. CONCLUSION: Robot-assisted and navigated transpedicular fusion techniques are both effective and safe. Robot-assisted transpedicular spine fusion goes along with higher placement accuracy but its implementation needs an adequate learning curve.

Unilateral Approaches for Posterior Spinal Canal Decompression in Cervical Spondylotic Myelopathy-An Evaluation of Conceptual Feasibility.

BACKGROUND: Patients with cervical spondylotic myelopathy (CSM) can be treated with posterior approaches for spinal canal decompression. OBJECTIVE: We compared the patients' outcome after 2 different unilateral and a bilateral posterior approach for decompression to elucidate feasibility and potential procedure-related differences. METHODS: Medical records of 98 patients with CSM undergoing posterior decompression between 2012 and 2018 were assessed. Patients were divided into 3 groups: (1) unilateral interlaminar fenestration with over-the-top "undercutting" (laminotomy) for compression limited to a ligamentum flavum hypertrophy, (2) unilateral hemilaminectomy for lateralized compression with a combination of ligamentous hypertrophy and osseus stenosis, and (3) laminectomy/laminoplasty for circular osseous-ligamentous spinal canal narrowing. RESULTS: The mean age was 73 years (m:f = 1.4:1), and most frequent symptoms (mean duration: 15 months) were ataxia (69%) and sensory changes (57%). Main location of stenoses (median Naganawa Score = 3; mean anteroposterior spinal canal diameter = 7.7 ± 2.2 mm) was C3 to C6. Thirty-one percent of the patients were assigned for a laminotomy procedure, 20% for a hemilaminectomy, and 49% for a laminectomy/laminoplasty. There were no significant differences of patients' characteristics, blood loss, and operation time between the 3 groups. Independent from the mode of surgery, the spinal canal was significantly widened (median Naganawa Score = 0; mean anteroposterior diameter = 11.4 ± 3.6 mm) and myelopathy (mJOA Score) improved ( P < .001); a higher body mass index was significantly correlated with a worse mJOA improvement (r = 0.293/ P = .003). Quality of life (Short-Form 36v2 Health Survey/Neck Disability Index) and reduction of the neck pain level were similar in the 3 groups at last follow-up (mean: 28 months). CONCLUSION: To minimize patients' periprocedural burden in CSM with dorsal compression, individual tailoring of the posterior approach according to the underlying compressive pathology achieves sufficient decompression and comparable long-term results.

Contribution of matrix metalloproteinase-9 to cerebral edema and functional outcome following experimental subarachnoid hemorrhage.

BACKGROUND: Cerebral edema is an important risk factor for death and poor outcome following subarachnoid hemorrhage (SAH). However, underlying mechanisms are still poorly understood. Matrix metalloproteinase (MMP)-9 is held responsible for the degradation of microvascular basal lamina proteins leading to blood-brain barrier dysfunction and, thus, formation of vasogenic cerebral edema. The current study was conducted to clarify the role of MMP-9 for the development of cerebral edema and for functional outcome after SAH. METHODS: SAH was induced in FVB/N wild-type (WT) or MMP-9 knockout (MMP-9(-/-)) mice by endovascular puncture. Intracranial pressure (ICP), regional cerebral blood flow (rCBF), and mean arterial blood pressure (MABP) were continuously monitored up to 30 min after SAH. Mortality was quantified for 7 days after SAH. In an additional series neurological function and body weight were assessed for 3 days after SAH. Subsequently, ICP and brain water content were quantified. RESULTS: Acute ICP, rCBF, and MABP did not differ between WT and MMP-9(-/-) mice, while 7 days' mortality was lower in MMP-9(-/-) mice (p = 0.03; 20 vs. 60%). MMP-9(-/-) mice also exhibited better neurological recovery, less brain edema formation, and lower chronic ICP. CONCLUSIONS: The results of the current study suggest that MMP-9 contributes to the development of early brain damage after SAH by promoting cerebral edema formation. Hence, MMP- 9 may represent a novel molecular target for the treatment of SAH.

Molecular diagnostics helps to identify distinct subgroups of spinal astrocytomas.

Primary spinal cord astrocytomas are rare, hence few data exist about the prognostic significance of molecular markers. Here we analyze a panel of molecular alterations in association with the clinical course. Histology and genome sequencing was performed in 26 spinal astrocytomas operated upon between 2000 and 2020. Next-generation DNA/RNA sequencing (NGS) and methylome analysis were performed to determine molecular alterations. Histology and NGS allowed the distinction of 5 tumor subgroups: glioblastoma IDH wildtype (GBM); diffuse midline glioma H3 K27M mutated (DMG-H3); high-grade astrocytoma with piloid features (HAP); diffuse astrocytoma IDH mutated (DA), diffuse leptomeningeal glioneural tumors (DGLN) and pilocytic astrocytoma (PA). Within all tumor entities GBM (median OS: 5.5 months), DMG-H3 (median OS: 13 months) and HAP (median OS: 8 months) showed a fatal prognosis. DMG-H3 tend to emerge in adolescence whereas GBM and HAP develop in the elderly. HAP are characterized by CDKN2A/B deletion and ATRX mutation. 50% of PA tumors carried a mutation in the PIK3CA gene which is seemingly associated with better outcome (median OS: PIK3CA mutated 107.5 vs 45.5 months in wildtype PA). This exploratory molecular profiling of spinal cord astrocytomas allows to identify distinct subgroups by combining molecular markers and histomorphology. DMG-H3 tend to develop in adolescence with a similar dismal prognosis like GBM and HAP in the elderly. We here describe spinal HAP with a distinct molecular profile for the first time.

Intramedullary low grade astrocytoma and ependymoma. Surgical results and predicting factors for clinical outcome.

INTRODUCTION: The optimal time point for surgery of intramedullary spinal astrocytomas and ependymomas is often debated on, as predicting factors are poorly defined. The current single-institutional study was conducted to retrospectively analyze prognostic factors for postoperative functional outcome in these patients. MATERIAL AND METHODS: All consecutive adult patients with intramedullary astrocytomas or ependymomas (except filum terminale ependymomas) were included. Imaging data, McCormick score (MCS), and detailed neurological evaluation were stringently applied preoperatively, 1 week, and 6 months postoperatively for functional evaluation of all patients. End points were early and late functional outcome. Prognostic factors were obtained from univariate and multivariate logistic regression analysis. RESULTS: Forty-four patients were included (29 ependymomas World Health Organization (WHO) grades I or II, 8 astrocytomas WHO grade I, and 7 astrocytomas WHO grade II). Overall perioperative morbidity was 34%, and there was no mortality. Complete tumor resection was achieved in 79% of ependymomas, 50% of astrocytomas WHO grade I, and 14% of astrocytomas WHO grade II (significantly more often in ependymomas than in astrocytomas, p < 0.05). Early and late functional outcome were highly intercorrelated (p < 0.01), but not correlated to histology. Preoperative MCS <3 and extent of tumor <5 levels were significantly (p = 0.01 and p < 0.05) associated with a favorable outcome (MCS <3) in early and late follow-up. CONCLUSION: An MCS of less than 3 and a tumor extent of less than 5 levels are the most important factors for a favorable postoperative functional outcome. Therefore, surgery should be initiated before significant clinical symptomatology or substantial tumor growth occurs.

CT-Based Classification of Acute Cerebral Edema: Association with Intracranial Pressure and Outcome.

BACKGROUND AND PURPOSE: Brain edema after acute cerebral lesions may lead to raised intracranial pressure (ICP) and worsen outcome. Notwithstanding, no CT-based scoring system to quantify edema formation exists. This retrospective correlative analysis aimed to establish a valid and definite CT score quantifying brain edema after common acute cerebral lesions. METHODS: A total of 169 CT investigations in 60 patients were analyzed: traumatic brain injury (TBI; n = 47), subarachnoid hemorrhage (SAH; n = 70), intracerebral hemorrhage (ICH; n = 42), and ischemic stroke (n = 10). Edema formation was classified as 0: no edema, 1: focal edema confined to 1 lobe, 2: unilateral edema > 1 lobe, 3: bilateral edema, 4: global edema with disappearance of sulcal relief, and 5: global edema with basal cisterns effacement. ICP and Glasgow Outcome Score (GOS) were correlated to edema formation. RESULTS: Median ICP values were 12.0, 14.0, 14.9, 18.2, and 25.9 mm Hg in grades 1-5, respectively. Edema grading significantly correlated with ICP (r = .51; P < .0001) in focal and global cerebral edema, particularly in patients with TBI, SAH, and ICH (r = .5, P < .001; r = .5; P < .0001; r = .6, P < .0001, respectively). At discharge, 23.7% of patients achieved a GOS of 5 or 4, 65.0% reached a GOS of 3 or 2, and 11.9% died (GOS 1). CT-score of cerebral edema in all patients correlated with outcome (r = -.3, P = .046). CONCLUSION: The proposed CT-based grading of extent of cerebral edema significantly correlated with ICP and outcome in TBI, SAH, and ICH patients and might be helpful for standardized description of CT-images and as parameter for clinical studies, for example, measuring effects of antiedematous therapies.

Diffusion Tensor Imaging for Surgical Planning in Patients with Cervical Spondylotic Myelopathy.

BACKGROUND AND STUDY AIMS/OBJECTIVE: Despite its invasiveness, computed tomography myelography (CTM) is still considered an important supplement to conventional magnetic resonance imaging (MRI) for preoperative evaluation of multilevel cervical spondylotic myelopathy (CSM). We analyzed if diffusion tensor imaging (DTI) could be a less invasive alternative for this purpose. MATERIAL AND METHODS: In 20 patients with CSM and an indication for decompression of at least one level, CTM was performed preoperatively to determine the extent of spinal canal/cerebrospinal fluid (CSF) space and cord compression (Naganawa score) for a decision on the number of levels to be decompressed. Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) were correlated with these parameters and with MRI-based increased signal intensity (ISI). Receiver operating characteristic analysis was performed to determine the sensitivity to discriminate levels requiring decompression surgery. European Myelopathy Score (EMS) and neck/radicular visual analog scale (VAS-N/R) were used for clinical evaluation. RESULTS: According to preoperative CTM, 20 levels of maximum and 16 levels of relevant additional stenosis were defined and decompressed. Preoperative FA and particularly ADC showed a significant correlation with the CTM Naganawa score but also with the ISI grade. Furthermore, both FA and ADC facilitated a good discrimination between stenotic and nonstenotic levels with cutoff values < 0.49 for FA and > 1.15 × 10-9 m2/s for ADC. FA and especially ADC revealed a considerably higher sensitivity (79% and 82%, respectively) in discriminating levels requiring decompression surgery compared with ISI (55%). EMS and VAS-N/R were significantly improved at 14 months compared with preoperative values. CONCLUSION: DTI parameters are highly sensitive at distinguishing surgical from nonsurgical levels in CSM patients and might therefore represent a less invasive alternative to CTM for surgical planning.

A high-definition 3D exoscope as an alternative to the operating microscope in spinal microsurgery.

OBJECTIVE: Since the 1970s, the operating microscope (OM) has been a standard for visualization and illumination of the surgical field in spinal microsurgery. However, due to its limitations (e.g., size, costliness, and the limited movability of the binocular lenses, in addition to discomfort experienced by surgeons due to the posture required), there are efforts to replace the OM with exoscopic video telescopes. The authors evaluated the feasibility of a new 3D exoscope as an alternative to the OM in spine surgeries. METHODS: Patients with degenerative pathologies scheduled for single-level lumbar or cervical spinal surgery with use of a high-definition 3D exoscope were enrolled in a prospective cohort study between January 2019 and September 2019. Age-, sex-, body mass index-, and procedure-matched patients surgically treated with the assistance of the OM served as the control group. Operative baseline and postoperative outcome parameters were assessed. Periprocedural handling, visualization, and illumination by the exoscope, as well as surgeons' comfort level in terms of posture, were scored using a questionnaire. RESULTS: A 3D exoscope was used in 40 patients undergoing lumbar posterior decompression (LPD) and 20 patients undergoing anterior cervical discectomy and fusion (ACDF); an equal number of controls in whom an OM was used were studied. Compared with controls, there were no significant differences for mean operative time (ACDF: 132 vs 116 minutes; LPD: 112 vs 113 minutes) and blood loss (ACDF: 97 vs 93 ml; LPD: 109 vs 55 ml) as well as postoperative improvement of symptoms (ACDF/Neck Disability Index: p = 0.43; LPD/Oswestry Disability Index: p = 0.76). No intraoperative complications occurred in either group. According to the attending surgeon, the intraoperative handling of instruments was rated to be comparable to that of the OM, while the comfort level of the surgeon's posture intraoperatively (especially during "undercutting" procedures) was rated as superior. In cases of ACDF procedures and long approaches, depth perception, image quality, and illumination were rated as inferior when compared with the OM. By contrast, for operating room nursing staff participating in 3D exoscope procedures, the visualization of intraoperative process flow and surgical situs was rated to be superior to the OM, especially for ACDF procedures. CONCLUSIONS: A 3D exoscope seems to be a safe alternative for common spinal procedures with the unique advantage of excellent comfort for the surgical team, but the drawback is the still slightly inferior visualization/illumination quality compared with the OM.