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Background and Purpose— Many patients with acute ischemic stroke are not eligible for thrombolysis or mechanical reperfusion therapies due to contraindications, inaccessible vascular occlusions, late presentation, or large infarct core. Sphenopalatine ganglion (SPG) stimulation to enhance collateral flow and stabilize the blood-brain barrier offers an alternative, potentially more widely deliverable, therapy. Methods— In a randomized, sham-controlled, double-masked trial at 41 centers in 7 countries, patients with anterior circulation ischemic stroke not treated with reperfusion therapies within 24 hours of onset were randomly allocated to active SPG stimulation or sham control. The primary efficacy outcome was improvement beyond expectations on the modified Rankin Scale of global disability at 90 days (sliding dichotomy), assessed in the modified intention-to-treat population. The initial planned sample size was 660 patients, but the trial was stopped early when technical improvements in device placement occurred, so that analysis of accumulated experience could be conducted to inform a successor trial. Results— Among 303 enrolled patients, 253 received at least one active SPG or sham stimulation, constituting the modified intention-to-treat population (153 SPG stimulation and 100 sham control). Age was median 73 years (interquartile range, 64–79), 52.6% were female, deficit severity on the National Institutes of Health Stroke Scale was median 11 (interquartile range, 9–15), and time from last known well median 18.6 hours (interquartile range, 14.5–22.5). For the primary outcome, improved 3-month disability beyond expectations, rates in the SPG versus sham treatment groups were 49.7% versus 40.0%; odds ratio, 1.48 (95% CI, 0.89–2.47); P =0.13. A significant treatment interaction with stroke location (cortical versus noncortical) was noted, P =0.04. In the 87 patients with confirmed cortical involvement, rates of improvement beyond expectations were 50.0% versus 27.0%; odds ratio, 2.70 (95% CI, 1.08–6.73); P =0.03. Similar response patterns were observed for all prespecified secondary efficacy outcomes. No differences in mortality or serious adverse event safety end points were observed. Conclusions— SPG stimulation within 24 hours of onset is safe in acute ischemic stroke. SPG stimulation was not shown to statistically significantly improve 3-month disability above expectations, though favorable outcomes were nominally higher with SPG stimulation. Beneficial effects may distinctively be conferred in patients with confirmed cortical involvement. The results of this study need to be confirmed in a larger pivotal study. Clinical Trial Registration— URL: https://www.clinicaltrials.gov . Unique identifier: NCT03767192.

Background and purpose Intracranial aneurysms are a known but rare complication of radiotherapy (RT). We reviewed the angiographic and clinical outcomes of intracranial aneurysms following RT in patients with nasopharyngeal carcinoma (NPC), a malignancy endemic in Hong Kong. Materials and methods The clinical, angiographic and laboratory data was collected for nine NPC patients harboring fifteen intracranial aneurysms following RT, diagnosed between 1st January 2000 and 31st December 2012. Results The median age at aneurysm diagnosis was 56 years with a male predilection (67%). The median latent period to diagnosis was nine years (0.3–30). Eight patients (89%) presented with aneurysmal subarachnoid hemorrhage. Nine aneurysms were located at the anterior circulation, and 14 were saccular in morphology. Of the treated aneurysms, eight underwent endovascular intervention and two were surgically clipped. Within a year, 50% of the treated aneurysms had recurred. Poor neurological outcome was noted. At two-year follow-up, the median score for modified Rankin score and Glasgow Outcome score was 5 and 2 respectively. The two-year mortality rate of patients with treated ruptured intracranial aneurysms was 50%. Conclusion Compared to previous studies, our irradiated NPC patients had higher mortality and morbidity rates after aneurysm rupture and a higher angiographic recurrence rate following treatment. Greater vigilance is required in the detection of post-treatment recurrence of these aneurysms due to the higher risk of rupture. The authors recommend dedicated screening of intracranial aneurysms by active surveillance in routine CT protocols or the addition of three-dimensional time-of-flight magnetic resonance angiography in MR protocols.

Objective : Several modalities are available for volumetric measurement of the intracranial aneurysm. We discuss the challenges involved in manual segmentation, and analyze the application of alternative methods using automatic segmentation and geometric formulae in measurement of aneurysm volumes and coil packing density. Methods : The volumes and morphology of 38 aneurysms treated with endovascular coiling at a single center were measured using three-dimensional rotational angiography (3DRA) reconstruction software using automatic segmentation. Aneurysm volumes were also calculated from their height, width, depth, size of neck, and assumed shape in 3DRA images using simple geometric formulae. The aneurysm volumes were dichotomized as "small" or "large" using the median volume of the studied population (54 mm3 ) measured by automatic segmentation as the cut-off value for further statistical analysis. Results : A greater proportion of aneurysms were categorized as being "small" when geometric formulae were applied. The median aneurysm volumes obtained were 54.5 mm3 by 3DRA software, and 30.6 mm 3 using mathematical equations. An underestimation of aneurysm volume with a resultant overestimation in the calculated coil packing density (p = 0.002) was observed. Conclusion : Caution must be exercised in the application of simple geometric formulae in the management of intracranial aneurysms as volumes may potentially be underestimated and packing densities falsely elevated. Future research should focus on validation of automatic segmentation in volumetric measurement and improving its accuracy to enhance its application in clinical practice.

Background A post-irradiated carotid pseudoaneurysm at the skull base can cause life-threatening blowout syndrome. Conventional treatments include parent vessel occlusion, endovascular coiling or covered stenting. Use of the Pipeline embolization device (PED) for pseudoaneurysm exclusion at the skull base is not well described. Objective To report the clinical and angiographic outcome after using multiple PEDs to treat recently ruptured radiation-induced carotid pseudoaneurysms at the skull base. Methods Retrospective review of the clinical and angiographic records of patients who received PEDs as primary treatment for skull base carotid pseudoaneurysm between April 1, 2011 to March 31, 2013. Results Seven patients (five men, two women) with a mean age of 58 years (range 47–65) were treated in the study period. Primary treatment with the PED alone, with adjunct coil embolization in two patients, achieved immediate hemostasis in all patients, with no pseudoaneurysm rebleeding after a mean follow-up of 15.3 months (range 4–24 months). One patient had periprocedural cerebral infarction. Delayed internal carotid artery occlusion secondary to in-stent thrombosis occurred in three patients, one of whom had lacunar infarct and two remained asymptomatic. Conclusions Endovascular treatment with the PED was effective in excluding skull base post-irradiated carotid pseudoaneurysms and preventing recurrent blowout. However, the risk of ischemic complications in this group of patients was high and our experience did not support the use of flow diverters as a first-line treatment for this condition.

The Pipeline embolization device (PED) is one of the flow-diverting stents approved for the treatment of unruptured large or wide-necked cerebral aneurysms in 2011. Its use has now been extended to the treatment of recently ruptured dissecting cerebral aneurysm, carotid pseudoaneurysm from radiation injury, and blister aneurysms. We aimed to evaluate the effectiveness of utilizing the PED as a primary treatment for ruptured dissecting intracranial aneurysms. A single center retrospective review was conducted for all patients primarily treated with PED for acute subarachnoid hemorrhage (SAH) from ruptured dissecting cerebral aneurysms between December 2010 and February 2013. Patients were followed up with CT angiogram (CTA) or digital subtraction angiogram (DSA). Eight patients with a total of eight dissecting aneurysms were identified. The mean duration from SAH to treatment was 2.5 days. Six of the aneurysms arose from vertebral arteries and two from the basilar artery. Immediate check-DSA confirmed satisfactory contrast stasis in all eight cases, and complete aneurysmal obliteration was achieved at six months. There were two (25%) procedure-related complications, but no major procedure-related complications, such as thromboembolic events or rebleeding from aneurysm were encountered. The PED is a feasible treatment option for ruptured dissecting cerebral aneurysms in acute phase. According to our experience, using PED as flow-diverters in acute SAH does not significantly increase the complication risks or mortality rate if the antiplatelet regime is carefully monitored. Future studies shall evaluate the optimal antiplatelet regimen for using the PED in the acute phase.

Different brain tumors of distinct histology can co-exist in the setting of phakomatoses or as a complication of radiotherapy. In the absence of these predisposing factors, this phenomenon is uncommon. When the lesions are in close proximity they are described as collision tumors and are extremely rare. A 58-year-old woman presented with persistent headache and cognitive decline for three months. Magnetic resonance imaging revealed a tumor arising from the atrium of the left lateral ventricle with heterogeneous contrast enhancement. This intraventricular lesion was adjacent to another extensive infiltrating tumor of the basal cisterns. Operative findings revealed a vascular ventricular tumor and gross total resection was achieved. An adjacent avascular basal cistern tumor with a pearly white sheen was encountered and partial excision was performed. The histopathological diagnosis was central neurocytoma and epidermoid tumor. There is only one documented description of a central neurocytoma co-existing with a tumor of different pathology. To our knowledge, this is the first reported collision tumor case involving central neurocytoma. Since the incidence of both lesions co-existing juxtaposed is extremely low, a chronic oncogenetic inflammatory process stimulated by the epidermoid tumor to the subventricular region is suggested. Other mechanisms for tumor collision are discussed and we suggest a classification system for this rare association to reflect their pathogenesis.

Background Human placenta is a convenient resource for biomedical research, and has not yet been used for neurointerventional surgery research. Objective Our objective was to explore the feasibility of using human placenta to test various endovascular interventions and for training. Design 18 placentas soon after delivery were prepared for six pilot studies. (1) Study on anatomical similarity to human cerebral vessel. (2) Simulation of stent assisted coiling and flow diversion on an aneurysm model. (3) Simulation of intra-arterial thrombolysis. (4) Simulation of embolization of arteriovenous malformation with glues. (5) Simulation of mechanical thrombolysis and comparison of different devices. (6) Vascular model for training of neurointerventionalists. Results When the chorionic plate vessels were compared with the cerebral cortical vessels, similarities were found in vascular branch patterns, histological cross sections, and angiographic appearances. Due to the semitransparency of its vessel wall, performance of flow diverter and stent assisted coiling of an aneurysm could be visualized under direct microscopic observation. Similarly, timing of clot lysis and glue polymerization could be estimated. Endothelial change after thrombectomy could be assessed by histological methods. From these pilot studies, the placenta model could be adopted to simulate various clinical situations. It is also ideal for interventional radiology training. Conclusions It is feasible to adopt the human placenta as an ex vivo vascular model in neurointerventional surgery research due to the fact that its vessels resemble the brain vasculature.

Mesenchymal stem cells (MSCs) from adult exhibit self-renewal and multilineage differentiation capacities, making the MSCs promising candidates for cell therapy and tissue engineering. Although bone marrow (BM) is the most universal source of MSCs, other tissues may also contain MSCs. Peripheral blood (PB), in particular, arises as the most attractive source of MSCs due to easy accessibility and noninvasive procedure. However, it is not certain that PB-MSCs have the equal biological characteristics to those of BM-MSCs. The purpose of this study was to compare the biological characteristics between BM-MSCs and PB-MSCs. We adopted granulocyte colony-stimulating factor combined with CXCR4 antagonist AMD3100 to stimulate MSCs to release into blood circulation of the rats. PB-MSCs were obtained from mobilized PB and expanded in long-term culture. BM-MSCs were isolated from the femur and tibia medullary canal of the same rats by density gradient centrifugation. After cell expansion in vitro, cell surface markers and multipotentiality analysis were performed to identify MSCs. Apoptosis resistance to H(2)O(2)-induced apoptosis, proliferation kinetics, cellular senescence, and karyotype analysis were measured to compare the biological characteristics of PB-MSCs and BM-MSCs. PB-MSCs with the typical adherent fibroblast-like morphology were similar to that of BM-MSCs. Both PB-MSCs and BM-MSCs were positive for CD44 and CD90, and negative for CD34 and CD45. They both exhibited trilineage differentiation potential and expressed lineage-specific genes. Although the BM-MSCs showed stronger osteogenic and adipogenic differentiation, PB-MSCs displayed a more chondrogenic capacity. Further, BM-MSCs have greater proliferation ability. Apoptosis resistance and cellular senescence were similar in MSCs derived from both sources. The results of our study demonstrate that PB-MSCs have similar biological characteristics to those of BM-MSCs despite certain minor differences, suggesting PB as a possible alternative source for MSCs.

Surgeons do not give enough weight to the effects of bowing of the sagittal femoral shaft in total knee arthroplasty (TKA), which can result in damage to the cortex, fractures, or malalignment of the femoral component. To determine gender differences in bowing, we used spiral computed tomography to scan the femurs of 26 men and 47 women older than 50 years who required TKA. Skeletal extraction of the total sagittal femoral shaft from computed tomographic images was done by a matrix laboratory. The extracted curves were evenly divided into 3 sections. Comparison of the curvature on different sections of the same side of the femur showed that the distal third was significantly bowed. In addition, the curvature of the distal third was significantly larger in women than in men. Such morphological characteristics put forward new requirements in how intramedullary guide rods are used in TKA.

Intracranial aneurysm, a localized dilation of arterial blood vessels in the Circle of Willis and its branches, is potentially life threatening, due to massive bleeding in the subarachnoid space upon rupture. In clinical practice, one minimally invasive surgical procedure is the implantation of a metallic stent to cover the aneurysm neck. This flow diverting device can reduce the flow into the aneurysm and enhance the prospect of thrombosis, a condition expected to reduce the risk of growth and rupture. The biomechanical and haemodynamic factors in stented and nonstented situations are studied by computational fluid dynamics. Unlike earlier models with straight or curved parent blood vessels, the aneurysm is now located near an arterial bifurcation. The influence of the aspect (depth to neck) ratio of the aneurysm on the flow dynamics will be emphasized, especially in the post-operation stages. More precisely, the maximum flow velocity, the variations of wall shear stress, the risk of stent migration and volumetric flow rate after endovascular treatment will be studied. Aneurysms with larger aspect ratios (i.e. smaller neck sizes for constant depth) generally pose a greater risk in terms of these flow parameters. These results will assist the applications and design of stents in future neurosurgical therapy. The approach is limited to a nonelastic model, without taking into account of questions like stent expansion and interaction with tissue.

Patients with hereditary hemorrhagic telangiectasia (HHT) are at risk for the development of cerebral arteriovenous malformations (AVMs). The authors report a case of a spontaneously regressing cerebral AVM in a patient with HHT. The lesion was diagnosed on the basis of findings on screening magnetic resonance imaging and regressed completely before any treatment was undertaken. The spontaneous regression of cerebral AVMs is a rare and poorly understood phenomenon. Only one other instance of spontaneous regression of a cerebral AVM in a patient with HHT has been reported in the literature. The authors compare angiographic and clinical features in previously reported cases of spontaneous regression of cerebral AVMs with those in the present case to determine the characteristics common to this phenomenon.

Objective: To review the pattern of head injury among the paediatric population. Method: The hospital records of all patients younger than 12 years of age who had been admitted to the Neurosurgical Department at Tuen Mun Hospital for head injury between January 1992 and June 1996 were reviewed. The demographic data, causes and location of injury, initial Glasgow Coma Scale, associating symptoms and signs, radiological findings, and outcome were analyzed. Results: A total of 1240 patients were registered, the male to female ratio being 1.7 : 1. Annual incidence was 1.7 per 1000 population, and 41% of patients were younger than 1 year of age. Fall was the commonest cause, accounting for 77.5% of the cases, followed by accidental blow (13.5%), and traffic accident (7.9%). Of theses cases, 1.9% had significant intracranial injuries, of which epidural haematoma accounted for 48% of this category. Conclusions: Recognizing the pattern of head injury among children helps to identify any high-risk groups and environment, which will then help us to design more appropriate preventive measures. Chinese Abstract Figure Chinese Abstract.

An intracranial aneurysm, abnormal swelling of the cerebral artery, may lead to undesirable rates of mortality and morbidity upon rupture. Endovascular treatment involves the deployment of a flow-diverting stent that covers the aneurysm orifice, thereby reducing the blood flow into the aneurysm and mitigating the risk of rupture. In this study, computational fluid dynamics analysis is performed on a bifurcation model to investigate the change in hemodynamics with various side branch diameters. The condition after the deployment of a pipeline embolization device is also simulated. Hemodynamic factors such as flow velocity, pressure, and wall shear stress are studied. Aneurysms with a larger side branch vessel might have greater risk after treatment in terms of hemodynamics. Although a stent could lead to flow reduction entering the aneurysm, it would drastically alter the flow rate inside the side branch vessel. This may result in side-branch hypoperfusion subsequent to stenting. In addition, two patient-specific bifurcation aneurysms are tested, and the results show good agreement with the idealized models. Furthermore, the peripheral resistance of downstream vessels is investigated by varying the outlet pressure conditions. This quantitative analysis can assist in treatment planning and therapeutic decision-making., published_or_final_version

The proliferation and apoptosis property of mesenchymal stem cells derived from peripheral blood (PB-MSCs) were investigated under hypoxia and serum deprivation conditions in vitro so as to evaluate the feasibility for autologous PB-MSCs applications in cartilage repair.MSCs were mobilized into peripheral blood by granulocyte colony stimulating factor (G-CSF) and AMD3100. The blood samples were collected from central ear artery of rabbits. Adhered cells were obtained by erythrocyte lysis buffer and identified as MSCs by adherence to plastic, spindle shaped morphology, specific surface markers, differentiation abilities into osteoblasts, adipocytes and chondroblasts in vitro under appropriate conditions. MSCs were cultured in four groups at different oxygen tension (20% O2 and 2% O2), with or without 10% fetal bovine serum (FBS) conditions: 20% O2 and 10% FBS complete medium (normal medium, N), 20% O2 and serum deprivation medium (D), 2% O2 and 10% FBS complete medium (hypoxia, H), 2% O2 and serum deprivation (HD). Cell proliferation was determined by CCK-8 assay. Apoptosis was detected by Annexin V/PI and terminal deoxynucleotide transferase dUTP nick end labeling (TUNEL) staining.Spindle-shaped adherent cells were effectively mobilized from peripheral blood by a combined administration of G-CSF plus AMD3100. These cells showed typical fibroblast-like phenotype similar to MSCs from bone marrow (BM-MSCs), and expressed a high level of typical MSCs markers CD29 and CD44, but lacked in the expression of hematopoietic markers CD45 and major histocompatibility complex Class II (MHC II). They could also differentiate into osteoblasts, adipocytes and chondroblasts in vitro under appropriate conditions. No significant morphological differences were found among the four groups. It was found that hypoxia could enhance proliferation of PB-MSCs regardless of serum concentration, but serum deprivation inhibited proliferation at the later stage of culture. Apart from that, hypoxia or serum deprivation could promote the apoptosis of PB-MSCs after 48 hours; the effect was stronger when these two conditions combined together. Furthermore, the effect of serum deprivation on apoptosis was stronger compared with that of hypoxia.PB-MSCs possess similar phenotypes as BM-MSCs. Their differentiation and proliferation abilities make them a new source of seed cells for ischemia-related cell therapy and tissue engineering in the field of the articular cartilage repair.

Several reports have shown the progression of articular cartilage degeneration after anterior cruciate ligament (ACL) reconstruction. No report has been published about the cartilage comparing changes after single-bundle (SB) and double-bundle (DB) ACL reconstructions. The purpose of this study was to evaluate the articular cartilage changes after SB and DB ACL reconstructions by second-look arthroscopy.Ninety-nine patients who received arthroscopic ACL reconstruction were retrospectively reviewed at an average of 14 months after reconstruction, 58 patients underwent SB ACL reconstruction and 41 patients underwent DB ACL reconstruction. Hamstring tendon autografts were used in all patients. Second-look arthroscopy was done in conjunction with the tibial staple fixation removal at least one year after the initial ACL reconstruction. Arthroscopic evaluation and grading of the articular cartilage degeneration for all patients were performed at the initial ACL reconstruction, and at the second-look arthroscopy.The average cartilage degeneration at the patellofemoral joint (PFJ) was found significantly worsened after both SB and DB ACL reconstructions. This worsening were not seen at medial tibiofemoral joint (TFJ) and lateral TFJ. Grade II cartilage damage was the most common. At second-look arthroscopy, the average patellar cartilage degeneration was 1.14 ± 0.14 (at first look 0.52 ± 0.11) for the SB group, and 1.22 ± 0.15 (at first look 0.56 ± 0.12) for the DB group. The average trochlear cartilage degeneration was 1.05 ± 0.16 (at fist look 0.10 ± 0.06) and 0.66 ± 0.17 (at fist look 0.17 ± 0.09), respectively. The average patellar cartilage degeneration showed no significant difference in both groups. However, the average trochlea cartilage degeneration in DB group was significantly less than in SB group.Patellofemoral cartilage degeneration continued to aggravate after ACL reconstruction. DB ACL reconstruction could significantly decrease the trochlea cartilage degeneration compared with SB ACL reconstruction.

To evaluate the clinical manifestations and the outcome of surgical treatment of discoid medial meniscus.Records of 13 patients with discoid medial meniscus were retrospectively reviewed for their epidemiology, clinical manifestations, operation methods, treatment outcome and radiographic characteristics.The 13 cases of discoid medial meniscal injury took up 1.5 ‰ of the overall meniscal injuries treated at our institute during the 44-year period. Patients presented with knee pain (13 patients), giving away (10 patients), swelling (9 patients) and snapping (9 patients). The most common physical signs were medial joint line tenderness (13 patients) and positive McMurray test (11 patients). Ten patients required total meniscectomy. There were excellent short-term results: the median Tegner score was 7, and the mean Lysholm score was 94.8 ± 2.4 at two-year follow-up. However, the long-term outcome was not as good with degenerative changes in the medial compartment of all the involved knees.The discoid medial meniscus is extremely rare. The clinical signs and symptoms of discoid medial meniscal injuries are similar to those of any other meniscal injury. No Wrisberg-ligament type abnormality was found. Meniscectomy for discoid medial meniscus produced promising short-term results and deteriorating long-term results with secondary degeneration of cartilage in the medial compartment.Retrospective case series, Level IV.

Background: The main diagnostic methods for evaluating repaired menisci include second-look arthroscopy, clinical assessment, and magnetic resonance imaging (MRI). None of the previous studies applied all 3 methods for each consecutive case nor made any systematic comparison among them. Purpose: This study was undertaken to compare the diagnostic values of the 3 different methods in an attempt to propose suggestions for evaluating meniscal healing results. Study Design: Cohort study (diagnosis); Level of evidence, 2. Methods: Eighty-one patients (89 menisci), with a mean age of 25.4 years (standard deviation [SD], 7.7; range, 15-50 years), underwent arthroscopic meniscal repair, including 65 medial menisci and 24 lateral menisci. Follow-up evaluation for each meniscus included clinical assessment, second-look arthroscopy, and postoperative MRI, with a mean follow-up time of 25.4 months (SD, 6.0; range, 17.4-48.3 months). Defined criteria for unhealed meniscus were any symptoms such as joint-line tenderness, swelling, locking, or positive McMurray test for clinical assessment; cleft or instability on second-look arthroscopy; and grade 3 signal intensity shown at the repaired site on postoperative MRI. Results: Seventy-seven menisci were confirmed completely healed by second-look arthroscopy, with a total healing rate of 86.5%. Clinical assessment found 63 menisci healed, with a clinical healing rate of 70.8% (sensitivity, 58.3%; specificity, 75.3%; accuracy, 73.0%). By using the second-look arthroscopy as the standard, the sensitivity, specificity, and accuracy, respectively, were calculated for MRI in 5 sequences: sagittal T1: 91.7%, 58.4%, 62.9%; sagittal proton density (PD): 83.3%, 40.3%, 46.1%; sagittal T2: 58.3%, 89.6%, 85.4%; coronal PD: 75.0%, 74.0%, 74.2%; and coronal T2: 41.7%, 98.7%, 91.0%. Conclusion: Second-look arthroscopy was the most dependable way to determine meniscal healing. Clinical assessment had obvious limitations in diagnosing healed menisci. On MRI examination, T2-weighted sequences had obviously higher specificity and accuracy, while PD and T1 had higher sensitivity. The diagnostic value could be improved by a combined application of different sequences.

Purpose The purpose was to find a simple guideline to help establish accurate positioning of the posterolateral bundle (PLB) femoral bone tunnel during double-bundle anterior cruciate ligament reconstruction by measuring the distance between the center of the PLB femoral footprint to the shallow and the deep articular cartilage borders of the lateral wall of the intercondylar notch. Methods The femoral insertions of the anteromedial bundle and PLB of the anterior cruciate ligament were dissected in 22 male cadaveric knees, aged 25 to 45 years. By use of the intercondylar notch as the landmark, the distances between the center of the PLB femoral footprint and the shallow and the deep articular cartilage borders of the lateral wall of the intercondylar notch were measured with the knees flexed at 90°. The measured data (mean ± standard deviation) were evaluated and compared. Results The center of the PLB was positioned 8.60 ± 1.52 mm and 8.65 ± 1.54 mm from the shallow and the deep cartilage borders of the lateral wall of the intercondylar notch, respectively ( P = .95). The distance between the center of the PLB footprint to the low cartilage border of the lateral intercondylar wall was 5.05 ± 0.76 mm. Conclusions The findings suggest that the position of the center of the PLB femoral footprint is at the middle of the line joining the shallow and the deep borders of the femoral cartilage. Clinical Relevance Surgeons can use our results as a guideline and use the PLB footprint remnant as a reference at the same time to locate the femoral PLB tunnel in a simple, easy, and repeatable way.

A 44-year-old woman with progressive cervical myelopathy and central cord syndrome was noted to have an extensive cervical intramedullary contrast-enhancing lesion on magnetic resonance imaging (MRI). The lesion resembled a spinal astrocytoma or ependymoma that required surgical intervention. She was subsequently diagnosed to have neuromyelitis optica (NMO), a rare idiopathic inflammatory demyelinating disorder, when the clinical examination revealed left optic atrophy. This was confirmed by a test showing seropositivity for NMO-immunoglobulin (IgG). Disease control was achieved with corticosteroids and immunosuppressive therapy. We report a rare case of a patient with NMO who had MRI features that could have easily led to the condition being misdiagnosed as a spinal cord tumor. The importance of careful history taking, awareness of typical radiological findings and the usefulness of serum NMO-IgG as a diagnostic tool are emphasized.