Can C1 lateral mass and C3 pedicle screw fixation be used as an option for atlantoaxial reduction and stabilization in Klippel-Feil patients? A study of its morphological feasibility, technical nuances, and clinical efficiency.

In Klippel-Feil patients with atlantoaxial dislocation, narrow C2 pedicles are often encountered preventing pedicle screw placement. Alternative techniques, including translaminar screws, pars screws, and inferior process screws could not achieve 3-column rigid fixation, and have shown inferior biomechanical stability. The present study aimed to evaluate the feasibility, safety, and efficacy of C3 pedicle screws (C3PSs) as an option for atlantoaxial stabilization in Klippel-Feil patients, and to introduce a freehand technique, the "medial sliding technique," for safe and accurate C3PS insertion. Thirty-seven Klippel-Feil patients with congenital C2-3 fusion who have received atlantoaxial fixation were reviewed. Preoperative CT and CT angiography were acquired to evaluate the feasibility of C3PS placement. C1 lateral mass and C3PS constructs were used for atlantoaxial stabilization. The "medial sliding technique" was introduced to facilitate C3PS insertion. Clinical outcomes and complications were evaluated, and screw accuracy was graded on postoperative CT scans. Morphological measurements showed that more than 80% C3 pedicles could accommodate a 3.5-mm screw. Fifty-eight C3PSs were placed in 33/37 patients using the medial sliding technique. Overall, 96.7% screws were considered safe and there was no related neurovascular complications; 27/33 patients exhibited neurological improvement and 30/33 patients had a solid bone fusion at an average 19.3-month follow-up. Therefore, the C3PS was a feasible option for atlantoaxial fixation in Klippel-Feil patients. The clinically efficiency of C3PS was satisfied with high fusion rates and low complications. The medial sliding technique we used could facilitate safe and accurate placement of C3PSs in Klippel-Feil patients with fused C2-3 vertebra.

Clinical features and long-term outcomes of pediatric spinal cord cavernous malformation-a report of 18 cases and literature review.

PURPOSE: Pediatric intramedullary spinal cord cavernous malformation (ISCM) is a rare vascular disease with unclear natural history and long-term outcomes. We aim to determine the demographics, hemorrhagic risk, and long-term outcomes of this rare entity. METHODS: A retrospective review of clinical data and treatment outcomes of pediatric patients treated with ISCM in our institution from 3/2000 to 3/2017 was conducted. In addition, we performed a systematic review of the literature on pediatric ISCM. RESULTS: Eighteen consecutive pediatric patients were included, with an average age of 12.9 ± 4.7 years (range: 4-18 years) and 66.7% being male. Locations were equally distributed in cervical and thoracic segments, with mean extension of 1.3 ± 0.7 segments. Clinical manifestation included extremity weakness (n = 15, 83.3%), pain (n = 10, 55.6%), sensory disorders (n = 8, 44.4%), sphincter disturbance (n = 6, 33.3%), muscular atrophy (n = 3, 16.7%), and spinal deformity (n = 1, 5.6%). Most patients presented with acute symptoms (n = 11, 61.1%), and 7 (38.9%) of them had severe neurological deficits. The annual retrospective hemorrhagic risk was 7.7 per patient-year. Two patients received conservative management, with one improved neurologically and the other remained unchanged. Total resection was achieved in 12 (75%) of the 16 surgical cases, with 8 patients (50%) improved their clinical outcomes, 7 patients (43.8%) remained unchanged, and 1 (6.3%) worsened. During follow-up, one patient had relapse of ISCM. CONCLUSION: Pediatric ISCM appears to have higher hemorrhage risk than their adult counterparts, and they can benefit from surgery whether in the acute phase of neurological deterioration or after clinical recuperation.

A novel surgical protocol for safe and accurate placement of C1 lateral mass screws in patients with atlas assimilation, basilar invagination and atlantoaxial instability: technical details, accuracy assessment and perioperative complications.

PURPOSE: To introduce a novel surgical protocol for safe and accurate placement of C1 lateral mass screws in patients with atlas assimilation, basilar invagination and atlantoaxial instability, and to categorize the screw accuracy and perioperative complications regarding this technique in a large case series. METHODS: Between January 2015 and January 2020, patients who had atlas assimilation, basilar invagination and atlantoaxial instability, and underwent atlantoaxial fixation using C1 lateral mass screws were reviewed. C1 lateral mass screws were placed with a novel surgical protocol following a series key steps, including posterior para-odontoid ligament release, panoramic exposure of the invaginated lateral mass, and diligent protection of the abnormal VA. Screw accuracy and related complications were specifically evaluated. RESULTS: A total of 434 C1 lateral mass screws were placed. Fifteen screws (3.5%) were classified as unacceptable, 54 screws (12.4%) were classified as acceptable, and 365 screws (84.1%) were classified as ideal. Overall, 96.5% of screws were deemed safe. There were no cases of vascular injury or permanent neurological defects. One patient with an unacceptable screw presented with hypoglossal nerve paralysis and recovered after an immediate revision surgery. Thirty-seven patients complained about occipital neuralgia and were successfully managed with medication. CONCLUSION: Placement of C1 lateral mass screws in patients with atlas assimilation, basilar invagination and atlantoaxial instability following this surgical protocol is safe and accurate. Thorough para-odontoid ligamental release, wide exposure of the invaginated lateral mass, and diligent protection of the vertebral artery are critical to maximize the chances of successful screw placement.

Clinical characteristics and long-term surgical outcomes of spinal pilocytic astrocytoma: a report of twenty cases.

BACKGROUND: Primary spinal pilocytic astrocytoma (PA) is an extremely rare low-grade astrocytoma with unclear natural history. The demographic characteristics, imaging features, and long-term surgical outcomes have not been clarified due to low prevalence and limited reports. METHODS: A retrospective review within a single institution between 2004 and 2018 of all patients with pathologically proven PA was conducted. Patient data including demographics, radiographic features, treatment modalities, and long-term outcomes were evaluated. RESULTS: Twenty consecutive patients were identified, and 16 (80%) were male patients, with a mean age at presentation of 29 ± 13 years. The lesion was primarily located in cervical (n = 10, 50%), thoracic (n = 7, 35%), cervico-thoracic junction (n = 2), and lumbar level (n = 1, 5%). The tumor had a mean extension of 4 ± 2 (1-7) vertebral segments. Most PAs were located eccentrically (n = 16, 80%), with most being heterogeneous in appearance (cystic and solid) or purely cystic (n = 14, 70%), and had unclear margins (n = 16, 80%). Eleven patients (55%) had associated syringomyelia. Gross total resection (GTR) was achieved in 11 (55%) patients, and subtotal resection (STR) in 9 (45%). During a mean follow-up of 104 ± 56 months, 2 patients died and recurrence was found in 4 patients (20%), translating to a mean progression-free survival of 21 ± 11 months. CONCLUSION: Primary spinal PA is a rare entity with acceptable progression-free survival if treated appropriately. Surgical resection may provide reasonable prolongation of survival, and GTR should be achieved if possible. A close follow-up is recommended especially for residual lesions, and a further in-depth investigation of molecular biomarkers is needed to stratify risk and prognostic factors.

Feasibility of occipital condyle screw placement in patients with Chiari malformation type I: a computed tomography-based morphometric study.

BACKGROUND: The occipital condyle (OC) screw is an alternative technique for occipitocervical fixation that is especially suitable for revision surgery in patients with Chiari malformation type I (CMI). This study aimed to investigate the feasibility and safety of this technique in patients with CMI. METHODS: The CT data of 73 CMI patients and 73 healthy controls were retrospectively analyzed. The dimensions of OCs, including length, width, height, sagittal angle, and screw length, were measured in the axial, sagittal, and coronal planes using CT images. The OC available height was measured in the reconstructed oblique parasagittal plane of the trajectory. RESULTS: The mean length, width, and height of OCs in CMI patients were 17.79 ± 2.31 mm, 11.20 ± 1.28 mm, and 5.87 ± 1.29 mm, respectively. All OC dimensions were significantly smaller in CMI patients compared with healthy controls. The mean screw length and sagittal angle were 19.13 ± 1.97 mm and 33.94° ± 5.43°, respectively. The mean OC available height was 6.36 ± 1.59 mm. According to criteria based on OC available height and width, 52.1% (76/146) of OCs in CMI patients could safely accommodate a 3.5-mm-diameter screw. CONCLUSIONS: The OC screw is feasible in approximately half of OCs in CMI patients. Careful morphometric analyses and personalized surgical plans are necessary for the success of this operation in CMI patients.

Clinical features and long-term surgical outcomes of pure spinal epidural cavernous hemangioma-report of 23 cases.

BACKGROUND: Pure spinal epidural cavernous malformation (CM) is a rare hypervascular disease that is easily misinterpreted as other imaging-similar epidural lesions. The demographic characteristics, therapeutic strategies, and surgical outcomes associated with this vascular entity remains unclear. METHODS: A retrospective review of patients with pathologically proven, pure epidural CM from 2001 to 2018 was conducted. All data that included clinical manifestations, radiographic features, and treatment modalities were analyzed. RESULTS: Twenty-three consecutive patients with an average age of 51.5 ± 8.4 years old (range 38-70 years old) were included; of these, 52.2% were female patients. Clinical manifestation included chronic progressive nerve root disturbance syndrome in 7 patients (30.4%) and myelopathy in 16 patients (69.6%). The CM level was predominately thoracic (n = 14, 60.9%) or lumbar (n = 6, 26.1%), with the dorsal epidural space (n = 14, 60.9%) the most common site. The initial clinical diagnoses were schwannoma (n = 11, 52.2%), meningioma (n = 5, 21.7%), angioma (n = 3, 13.1%), recurrent CMs (n = 2, 8.7%), and metastatic tumor (n = 1, 4.3%). Fifteen lesions (65.2%) were isointense on T1-weighted images, and all lesions were hyperintense on T2-weighted images, with homogenously strong enhancement observed in 17 lesions (73.9%). Total resection was achieved in 18 patients (78.3%) and usually resulted in excellent clinical outcomes (n = 21, 91.3%). No patients experienced recurrence of symptoms, and lesion relapse during follow-up. CONCLUSION: Total surgical removal of epidural CM can usually achieve satisfactory outcomes in patients with a chronic clinical course and should be recommended. Subtotal removal of tumors can also benefit patients, and guaranteed a long recurrent free time after surgery. A good preoperative neurological condition usually leads to good outcomes.

MSX1 inhibits cell migration and invasion through regulating the Wnt/ß-catenin pathway in glioblastoma.

Glioblastoma is a type of primary brain tumor with poor prognosis. The hallmark phenotype of glioblastoma is its aggressive invasion. Understanding the molecular mechanism of the invasion behavior of glioblastoma is essential for the development of effective treatment of the disease. In our present study, we found that the expression levels of a homeobox transcription factor, MSX1, were significantly reduced in glioblastoma compared to normal brain tissues. The levels of MSX1 in glioblastoma tissues were also correlated with the survival of the patients. In cultured glioblastoma cells, MSX1 was a negative regulator of cell migration and invasion. Loss of MSX1 enhanced cell migration and induced mesenchymal transition as characterized by the downregulation of E-cadherin and the upregulation of N-cadherin. Overexpression of MSX1 on the other hand led to the inhibition of both cell migration and mesenchymal transition. We also found that MSX1 was able to inhibit the Wnt/ß-catenin signaling pathway, and that the ability to regulate the Wnt/ß-catenin signaling pathway is critical for MSX1 to suppress glioblastoma cell migration and invasion.

[Analysis of 160 cases of C1 lateral mass screw fixation in patients with atlas occipitalization and occipito-cervical instability].

OBJECTIVE: To summarize the clinical effect of C1 lateral mass screw fixation in patients with atlas occipitalization and occipito-cervical instability (OCI). METHODS: Patients of atlas occipitalization and OCI from June 2007 to October 2013 which had been treated by C1 lateral mass fixation in our institution were retrospective analyzed. The clinical neurologic function improvement rate and bone fusion rate were investigated at follow-ups. The nuances of the C1 lateral mass insertion were summarized. RESULTS: Among the 160 patients, 1 patient died, 1 got worse, 1 was stable, 155 got recovery and 2 lost to follow-up. Among the 157 cases within 12-52 months follow-up (mean 34 months), 147 cases got reduction and release from the cervico-medullary junction compression and 10 got no effective reduction which were resumed to anterior decompression at second surgery.At one year follow-up, 155 cases had solid bony fusion and 2 had no evident fusion.The entry point for C1 screw was located at the midpoint of the posterior surface of C1 facet and the screw was directed approximately between 0-40° cephalad and approximately between 0-20° medially. CONCLUSIONS: C1 lateral mass screw fixation is a safe and feasible method and could provide solid stability in patients with atlas occipitalization and OCI. The risk of placement of C1 screw could be decreased to a low rate after the preoperative evaluation and trajectory design.

[Exploratory study of 3D printing technique in the treatment of basilar invagination and atlantoaxial dislocation].

OBJECTIVE: To investigate the clinical application value of the 3D printing technique in the treatment of basilar invagination and atlantoaxial dislocation. METHODS: From January 2013 to September 2013, 10 patients with basilar invagination and atlantoaxial dislocation needing posterior fixation undertook 3D printing modes at the Department of Neurosurgery in PLA General Hospital. The 1:1 size models were established from skull base to C4 level with different colors between bone structures and vertebral arteries. The simulation of screw insertion was made to investigate the fixation plan and ideal entry point to avoid vertebral artery injury. After obtaining the individual screw insertion data in 3D printing modes, the according surgical operations were performed. The actual clinical results and virtual screw data in 3D printing mode were compared with each other. RESULTS: The 3D printing modes revealed that all the 10 patients had the dysplasia or occipitalized C1 posterior arch indicating C1 posterior arch screw implantation was not suitable. C1 lateral masses were chosen as the screws entry points. C2 screws were designed individually based on the 3D printing modes as follows: 3 patients with aberrant vertebral artery or narrow C2 pedicle less than 3.5 mm were not suitable for pedicle screw implantation. Among the 3 patients, 1 was fixed with C2 laminar screw, and 1 with C2-3 transarticular screw and 1 with C3 pedicle screw (also combined with congenital C2-3 vertebral fusion). Two patients with narrow C2 pedicle between 3.5 and 4mm were designed to choose pedicle screw fixation after 3D printing mode evaluation. One patient with C1 lateral mass vertically dislocated axis was planned with C1-2 transarticular screw fixation. All the other patients were planned with C2 pedicle screws. All the 10 patients had operation designed as the 3D printing modes schemes. The follow-up ranged from 12 to 18 months and all the patients recovered from the clinical symptoms and the bony fusion attained to 100%. CONCLUSIONS: 3D printing mode could provide thorough information of the bony structure abnormalities and route of vertebral artery. It is helpful for setting operation strategy and designing screw entry point and trajectory and avoiding vertebral artery and spinal cord injury and thus deserves generalization.

[The value of electromyography in differentiating intramedullary tumor from inflammatory demyelinating disease of cervical region].

OBJECTIVE: To investigate the value of needle electromyography (EMG) in differentiating intramedullary tumor from inflammatory demyelinating disease of cervical region. METHODS: Patients hospitalized in the Chinese PLA General Hospital from March 2008 to June 2013 with abnormalities on MRI of cervical vertebra and preliminary diagnosed as intramedullary tumor or inflammatory demyelinating disease of cervical region were enrolled in the study. Electrophysiological examination was performed before any treatment. Pathological findings were analyzed and prognosis was evaluated in all the subjects. RESULTS: A total of fifty-five patients were enrolled in the study with 33 cases of inflammatory demyelinating disease and 22 cases of intramedullary tumor defined by the postoperative pathological findings. In all the 33 cases with demyelinating disease, only one case (3.03%) presented as neurogenic damage by needle EMG. While in all the 22 cases with intramedullary tumor, needle EMG revealed neurogenic damage in 15 cases (68.18%) and the spinal segments of muscles with neurogenic damage were all within the spinal lesions demonstrated by MRI. The diagnostic sensitivity of EMG for intramedullary tumor was 68.18% and the diagnostic specificity was 96.97%, while the diagnostic sensitivity and specificity for intramedullary tumor by the medical history, symptoms and signs were 59.09% and 75.76% respectively. CONCLUSION: Needle EMG might play an important role in distinguishing intramedullary tumor from inflammatory demyelinating disease of cervical spinal cord.

[Treatment of fixed atlantoaxial dislocation and basilar invagination with C1-2 screw and rod reduction and fixation technique].

OBJECTIVE: To introduce a novel technique of reducing fixed atlantoaxial dislocation (FAAD) and basilar invagination (BI) with C1-C2 screw and rod system. METHODS: From January 2009 to December 2011, 26 patients of FAAD and BI were reduced successfully with an insertion of C1 lateral mass and C2 pedicle/pars screw and rod system. The cohort had 17 females and 9 males. And their most common presenting symptoms were extremity muscle weakness, restricted neck movement and paresthesia. RESULTS: All of them achieved effective reduction. Among them, 18 attained complete reduction and 8 partial reduction (over 60% extent of reduction). The mean atlanto-dental interval (ADI) value was 2.1 mm postoperatively versus 8.8 mm preoperatively (t = 21.1, P < 0.01) . All of them had relieved compression of dura and medulla oblongata and cervical cord. All clinical symptoms improved. One case had pulmonary infection while another case delayed healing of incision. Both recovered well after symptomatic treatments. Bony fusion reached 100% during a mean follow-up period of 22 months. CONCLUSION: The C1-C2 screw and rod system may achieve effective reduction and fixation for FAAD and BI. Capable of preserving atlanto-occipital joints in patients without atlas assimilation, this procedure provide more solid immobilization than occipitocervical fusion in those with atlas assimilation.

Indirect Ventral Brainstem Decompression by Posterior C1-C2 Distraction and Fixation for Basilar Invagination.

OBJECTIVE: Basilar invagination usually shows a decrease of clivus axis angle (CAA), which could give rise to progressive neural compression. Exploring a safe and effective fixation technique to achieve atlantoaxial stability and neural decompression remains necessary. In this study, we introduce a modified posterior C1-C2 distraction and fixation technique by which we obtained indirect ventral neural decompression and atlantoaxial stability in a series of patients with decreased CAA. METHODS: Thirty patients of basilar invagination were enrolled in our series. All patients underwent thin-slice computed tomography (CT) scan, magnetic resonance imaging, and dynamic plain radiography examinations before surgery, at discharge and during the follow-ups. Posterior C1-C2 facet joint release and intraoperative reduction by fastening rods were performed in all patients. The CAA was measured on midsagittal CT scans. Patients' neurologic status was evaluated by the Japanese Orthopaedic Association score. RESULTS: No neurovascular injury and serious postoperative complication occurred in all patients. Complete ventral brainstem decompression was achieved in 20 patients and partial in 10 patients. The mean postoperative CAA significantly improved to 132.6 degrees compared with the preoperative 123.6 degrees (P < 0.01). The bone fusion was confirmed in all patients on the basis of the last follow-up spine CT scans. CONCLUSIONS: Indirect ventral brainstem decompression by posterior C1-C2 distraction and fixation is a safe and effective technique for treatment of basilar invagination.

Treatment of Reducible Atlantoaxial Dislocation and Basilar Invagination Using the Head Frame Reduction Technique and Atlantoaxial Arthrodesis.

STUDY DESIGN: Retrospective case series. OBJECT: To evaluate the outcomes of a head frame reduction and atlantoaxial arthrodesis technique for the treatment of reducible basilar invagination (BI) and atlantoaxial dislocation (AAD). METHODS: Seventy-two reducible BI and AAD cases who were treated with the head frame reduction and atlantoaxial arthrodesis technique from June 2015 to December 2018 were retrospectively analyzed. Radiological measurements including the atlantodental interval (ADI), the height of odontoid process above Chamberlain line, Wackenheim line, clivus-canal angle (CCA) and JOA score were evaluated. RESULTS: There was no death in this series. The follow-up period ranged from 6 to 32 months (mean: 21.2 months). Radiological, complete or 90% reduction was attained and complete decompression was demonstrated in all patients. The CCA increased from 123.22 ± 8.36 preoperatively to 143.05 ± 8.79 postoperatively (P < 0.01). There was no patient found postoperative dysphagia. Neurological improvement was observed in all patients, with the JOA scores increasing from 12.53 ± 1.93 preoperatively to 16.13 ± 1.23 postoperatively (P < 0.01). Solid bony fusion was demonstrated in 69 patients at follow-up (95.8%). CONCLUSION: Head frame reduction technique is a simple and effective treatment which could relief neurologic compression and adjust the CCA in patients with reducible AAD and BI with lower potential risks. Atlantoaxial fixation with short segmental fixation, strong purchase and low shearing force could maintain superior stabilization. The safety and long-term efficacy of such fixation and reduction technique were favorable, which illustrated that it could be a promising treatment algorithm for such kind of disease.

Spinal cord anaplastic oligodendroglioma with 1p deletion: report of a relapsing case treated with temozolomide.

Primary spinal cord oligodendroglial tumor is very rare, and in only one patient with spinal cord oligodendroglioma has a deletion of chromosome 1p/19q been reported. We present the case of an 18-year-old girl, who had one-year lower back pain and one-month lower limb weakness. Magnetic resonance images of the spinal cord showed an intramedullary mass from level T8 to T10, which was then radically removed. Histology revealed an anaplastic oligodendroglioma. The patient was treated with radiotherapy postoperatively. Eight months after the treatment, follow-up magnetic resonance images disclosed an enhancing intramedullary mass at level T4-T8; recurrence of the tumor was therefore diagnosed. Maximum surgical removal of the recurrent tumor was performed, diagnosis of anaplastic oligodendroglioma was made, and a chromosome 1p deletion was determined by FISH. After treatment with temozolomide for six months, the patient had a remarkable improvement of her lower limb symptoms, and complete imaging regression of the residual tumor showed no evidence of recurrence at any other sites. The most recent MRI of brain and spinal cord showed postoperative changes without evidence of tumor recurrence of the spine and oligodendrogliomatosis along the cerebral-spinal axis. To our knowledge, this is the first report of a recurrent anaplastic oligodendroglioma with 1p deletion occurring in the spinal cord. It is also the first case of the patient with recurrent intramedullary anaplastic oligodendroglioma who had a significant clinical improvement and complete imaging remission after subtotal resection then treatment with temozolomide chemotherapy.

Malignant transformation of intracranial meningeal melanocytoma. Case report and review of the literature.

Meningeal melanocytoma is an uncommon pigmented neoplasm that affects the CNS and develops in the cranial and spinal leptomeninges. Here we report on a case of malignant transformation of intracranial supratentorial meningeal melanocytoma which recurred after 3 years as malignant melanoma. This case demonstrates that the biological behavior of melanocytoma is uncertain and that these lesions may recur as malignant melanoma.

Intracranial recurrences of Rosai-Dorfman disease in the sellar region: two illustrative cases.

Rosai-Dorfman disease [RDD] is a condition of an unknown etiology, characterized by proliferation of histiocytes. Not uncommonly extranodal lesions occur, but sellar involvement is very rare. Treatment of this lesion is complicated, especially in cases of recurrences at multiple intracranial sites. We report two cases of RDD in the sellar region with intracranial recurrences to illustrate the clinicopathological features and considerations of the optimal management.

Long-term surgical outcomes and prognostic factors of adult symptomatic spinal cord cavernous malformations.

Cervical and thoracic or lumbar intramedullary spinal cavernous malformations (ISCMs) may behave differently. We conducted this retrospective study by using data from adult ISCMs to compare their natural histories and explore prognostic factors for improved clinical outcomes. Neurological functions were assessed by using the Modified McCormick Scale (MMCS) and Aminoff-Logue Disability Scale. A total of 111 study-eligible adult patients were included in this study. Patients with cervical ISCMs mostly demonstrated a shorter duration of symptoms (P = 0.026), an acute onset pattern with some recovery (P = 0.026), and a larger lesion size (P = 0.033) than their thoracic or lumbar counterparts. Thoracic or lumbar lesions had a higher proportion of motor symptoms (P = 0.001) and sphincter problems (P = 0.005), and they were usually associated with an aggressive clinical course (P = 0.001, OR = 9.491, 95% CI = 2.555-35.262) in multivariate analysis. There was no difference in age, sex distribution, hemorrhage risk between the cervical and thoracic-lumbar groups. A better preoperative neurological status (P = 0.034, OR = 2.768, 95% CI = 1.081-7.177) and improvement immediately after surgery (P < 0.001, OR = 8.756, 95% CI = 4.837-72.731) were identified as indicators for long-term improvement by multivariate analysis. Cervical lesions had a high proportion for long-term improvement, but it was not a predictor for improvement in multivariate analysis. ISCMs in the thoracic or lumbar location should be considered for surgical removal more aggressively than those in the cervical location. Surgical removal of symptomatic ISCMs can avoid further neurological deterioration and usually result in satisfactory long-term outcomes.

Long-term surgical outcomes of patients with delayed diagnosis of spinal dural arteriovenous fistula.

Spinal dural arteriovenous fistula (dAVF) is an extremely rare vascular entity that is usually misdiagnosed. We sought to determine the long-term clinical outcomes of patients undergoing microsurgical treatment for delayed diagnosis of spinal dAVF. This retrospective study identified patients with delayed diagnosed spinal dAVF at our institution from 2009 to 2018. Patients' data, including demographics, imaging, and follow-up data, were evaluated. This cohort included 65 consecutive patients with 68 dAVFs and a male-to-female ratio of 4:1 and a mean age of 53.5 ± 13.7 years. The presenting symptoms consisted of limb weakness (n = 42, 64.6%), paraparesis (n = 34, 52.3%), sphincter disturbances (n = 8, 12.3%), and pain (n = 13, 20.0%). The proportion of patients with each symptom significantly increased and patients experienced increased disability when the diagnosis was finalized. The mean length of delay of diagnosis was 20.7 ± 30.0 months. Surgery resulted in complete occlusion of the fistula on the first attempt in all patients. Three patients developed recurrent fistulas, and three died in the follow-up period. Improved motor function was achieved in 38 patients (59.5%). Other symptoms, such as sensory disorders, sphincter dysfunction, and pain, improved by 37.3%, 32.3%, and 66.7%, respectively. Patients with spinal dAVF usually exhibit progressive ascending myelopathy and often remain misdiagnosed for months to years. Some patients' increased disability cannot be reversed through surgery.

Surgical Treatment Outcomes of Patients with Conus Medullaris Teratoma: A Single-Center Experience of 39 Patients.

OBJECTIVE: Conus medullaris teratomas are extremely rare, and the treatment experience has been limited. The purpose of the present study was to evaluate the clinical characteristics, radiological features, surgical outcomes, and prognosis of patients with conus medullaris teratoma. METHODS: We retrospectively reviewed the data from 39 patients who had undergone surgical resection for conus medullaris teratomas from January 2008 to December 2018. All the operations were performed by 1 senior doctor. The clinical features, pre- and postoperative magnetic resonance imaging findings, pathological features, treatment strategies, and outcomes were analyzed. The neurological status was evaluated using the modified Japanese Orthopaedic Association scale score. RESULTS: Of the 39 patients, the mean age was 30.9 years. Of the 39 patients, 20 were male and 19 were female. The symptom duration ranged from 0.3 to 252 months (mean, 61.6 months). Bladder and bowel dysfunction was the most common symptom (76.9%). Total resection was achieved in 25 patients (64.1%), subtotal resection in 11 (28.2%), and partial resection in 3 (7.7%). A mature teratoma was confirmed in all 39 patients. The neurological outcomes were improved 16 patients (45.7%), stable in 14 (40.0%), and aggravated in 5 (14.3%) at a mean follow-up of 62.7 months. Recurrence developed in 1 patient who had undergone subtotal resection. A second surgery with total resection was performed, and the patient's neurological symptoms were stable during follow-up. CONCLUSIONS: Total surgical resection is the optimal treatment strategy for patients with conus medullaris teratoma. Safe maximum tumor removal and residual tumor inactivation using electrocoagulation are recommended when total resection cannot be achieved. Surgery can provide a low recurrence rate and an acceptable low complication rate.

C2 medial pedicle screw: a novel "in-out-in" technique as an alternative option for posterior C2 fixation in cases with a narrow C2 isthmus.

OBJECTIVE: The authors describe a novel "in-out-in" technique as an alternative option for posterior C2 screw fixation in cases that involve narrow C2 isthmus. Here, they report the preliminary radiological and clinical outcomes in 12 patients who had a minimum 12-month follow-up period. METHODS: Twelve patients with basilar invagination and atlantoaxial dislocation underwent atlantoaxial reduction and fixation. All patients had unilateral hypoplasia of the C2 isthmus that prohibited insertion of pedicle screws. A new method, the C2 medial pedicle screw (C2MPS) fixation, was used as an alternative. In this technique, the inner cortex of the narrow C2 isthmus was drilled to obtain space for screw insertion, such that the lateral cortex could be well preserved and the risk of vertebral artery injury could be largely reduced. The C2MPS traveled along the drilled inner cortex into the anterior vertebral body, achieving a 3-column fixation of the axis with multicortical purchase. RESULTS: Satisfactory C2MPS placement and reduction were achieved in all 12 patients. No instance of C2MPS related vertebral artery injury or dural laceration was observed. There were no cases of implant failure, and solid fusion was demonstrated in all patients. CONCLUSIONS: This novel in-out-in technique can provide 3-column rigid fixation of the axis with multicortical purchase. Excellent clinical outcomes with low complication rates were achieved with this technique. When placement of a C2 pedicle screw is not possible due to anatomical constraints, the C2MPS can be considered as an efficient alternative.