Granuloma formation as a late complication of burr-hole surgery for chronic subdural hematoma.

BACKGROUND: Surgical treatment remains the mainstream therapeutic regimen for chronic subdural hematoma (CSDH), and burr-hole craniostomy with subdural drainage is the preferable approach. Herein, we reported a case of intracranial granuloma formation as a late complication of burr-hole surgery for CSDH. CASE PRESENTATION: A 31-year-old man presented with a 1-month history of headache. Head computed tomography (CT) showed a subdural hematoma in the left frontal-temporal-parietal region with significant midline shifting. A burr-hole evacuation of the hematoma with closed-system drainage was performed. CT obtained immediately after the surgery demonstrated that the hematoma was mostly evacuated. Nine months later, he presented to us again due to intermittent headache in the left temporoparietal region. Brain magnetic resonance imaging revealed a space-occupying mass at the site of the original hematoma. A bone-flap craniotomy was performed for resecting the mass. Histopathological examination revealed a granuloma. The microbial cultivation of the resected specimen was negative. The postoperative course was uneventful, and the headache was relieved. CONCLUSION: Granuloma formation is an extremely rare late complication of burr-hole surgery for CSDH. Physicians involved in the perioperative management of CSDH should be aware of this condition, and bone-flap craniotomy may be warranted.

Sacral terminal filar cyst: a distinct variant of spinal meningeal cyst and midterm clinical outcome following combination resection surgery.

Objective: Spinal meningeal cysts (SMCs) are currently classified into three types: extradural cysts without nerve root fibers (Type I), extradural cysts with nerve root fibers (Type II), and intradural cysts (Type III). However, the sacral terminal filar cyst is a distinct subtype with the filum terminale rather than nerve roots within the cyst. This study aimed to investigate the clinicoradiological characteristics and surgical outcomes of sacral terminal filar cysts. Methods: A total of 32 patients with sacral terminal filar cysts were enrolled. Clinical and radiological profiles were collected. All patients were surgically treated, and preoperative and follow-up neurological functions were evaluated. Results: Chronic lumbosacral pain and sphincter dysfunctions were the most common symptoms. On MRI, the filum terminale could be identified within the cyst in all cases, and low-lying conus medullaris was found in 23 (71.9%) cases. The filum terminale was dissociated and cut off in all cases, and the cyst wall was completely resected in 23 (71.9%) cases. After a median follow-up period of 26.5 ± 15.5 months, the pain and sphincter dysfunctions were significantly improved (both P < 0.0001). The cyst recurrence was noted in only 1 (3.1%) case. Conclusions: Sacral terminal filar cysts are rare, representing a distinct variant of SMCs. Typical MRI features, including filum terminale within the cyst and low-lying conus medullaris, may suggest the diagnosis. Although the optimal surgical strategy remains unclear, we recommend a combination of resection of the cyst wall and dissociation of the filum terminale. The clinical outcomes can be favorable.

Multiple dimensions of radiographic reconstruction for the optimal operative strategy of sacral meningeal cysts.

BACKGROUND AND PURPOSE: The contents and subtypes of sacral cysts are sophisticated in many cases. We applied multiple dimensional magnetic resonance imaging (MRI) reconstruction to preoperatively clarify the specific subtype of sacral meningeal cysts. MATERIALS AND METHODS: We preoperatively used multimodal neural reconstruction MRI sequences to evaluate 76 patients with sacral cysts. The linear nerve roots were precisely traced based on sagittal or coronal images processed at various angles and levels which was conducive to the design of the operation strategy. RESULTS: Cysts with nerve passage were detected in 47 cases (62%, 47/76), whereas cysts without nerve roots were detected in 24 cases (32%, 24/76). Five patients had mixed cysts with or without nerve roots. Intraoperative exploration results proved the high accuracy of image reconstruction; only one cyst without a nerve root was misdiagnosed prior to surgery. CONCLUSION: MRI reconstruction based on the three-dimensional fast imaging employing steady-state acquisition T2 sequence precisely tracked the nerve roots of sacral cysts and guided the optimal strategy during surgery.

Case Report: Idiopathic Spinal Cord Herniation: An Overlooked and Frequently Misdiagnosed Entity.

Background: Idiopathic spinal cord herniation is an extremely rare entity that is characterized by protrusion of the spinal cord through a defect in the ventral dura. Due to the paucity of enough clinical evidence, the treatment and prognosis of idiopathic spinal cord herniation are still elusive. Herein, we reported a case of idiopathic spinal cord herniation occurring at the C7-T1 levels that was treated by surgical reduction. Case description: A 44-year-old Chinese woman presented with a 5-year history of numbness and weakness in the bilateral lower limbs. Spinal magnetic resonance imaging demonstrated ventral displacement of the spinal cord at the C7-T1 levels, and there seemed to be a cuneiform space-occupying lesion dorsal to the spinal cord. A diagnosis of the spinal intradural extramedullary tumor was suspected. An exploratory operation was performed via a posterior midline approach. Intraoperatively, we found a defect in the ventral dura through which the spinal cord herniated to the epidural space. After the herniated parenchyma was returned, an artificial dura matter was used to repair the defect. The postoperative course was uneventful. After a 3-month follow-up, the lower-extremity weakness was significantly improved, and there was no recurrence of the spinal cord herniation. Conclusion: Preoperative diagnosis of idiopathic spinal cord herniation is exceedingly challenging. Surgical reduction of the herniated spinal cord with the repair of the dural defect is an effective approach for the treatment of this rare disorder, and the surgical outcome is favorable.

Arachnoidal Diverticula of Sacral Extradural Meningeal Cyst: A Novel Definition and Case Series.

BACKGROUND: Sacral cysts are classically divided into Tarlov cysts and meningeal diverticula. However, the pathogenesis of sacral cysts remains unclear. This study aimed to clarify a novel type of sacral extradural spinal meningeal cyst with a specific arachnoidal structure. METHODS: Nine patients with prophylactic diverticula were included in the study. All patients underwent MRI preoperative reconstruction and traditional neck transfixation. RESULTS: All patients presented with more than one symptom. The major symptom was lower extremity pain, followed by lower extremity numbness (77.8%, 7/9), lower extremity weakness (55.6%, 5/9), bowel/bladder and sexual dysfunction (55.6%, 5/9), and tenesmus (22.2%, 2/9). After long-term follow-up, the outcome was classified as improved in 9 patients (100%). CONCLUSIONS: The clinical findings of this study illustrate a special subtype and may help explain the mechanism of sacral cyst formation.

Spinal cysticercosis: a rare cause of myelopathy.

BACKGROUND: Neurocysticercosis is a neuroinfectious disease caused by the larval stage of the tapeworm Taenia solium. Isolated spinal cysticercosis is rare, with limited cases having been reported in the literature. This entity poses great diagnostic and therapeutic challenges. METHODS: This retrospective study included seven patients pathologically diagnosed with spinal cysticercosis. The clinical manifestations, radiological features on magnetic resonance imaging (MRI), treatment, and outcomes were analyzed. RESULTS: This case series consisted of four male and three female patients, with an average age of 34.9 ± 10.9 years. Clinically, six patients manifested with localization-related myelopathy. There were four solid lesions, one cystic-solid lesion, and three cystic lesions. The solid and cystic-solid lesions showed characteristic MRI features: 1) within the lesion, there was a mural nodule with isointensity on T1WI and iso- to hyperintensity on T2WI; 2) the signals at the periphery of the mural nodule were variable, ranging from hypointense to hyperintense on T2WI; and 3) ring-like or cyst wall enhancement could be present, and dot-like enhancement could be noted in the mural nodule. Complete resection of the responsible lesion was achieved in all patients, and oral albendazole was administered in a patient with one more suspected homologous lesion. After a mean follow-up period of 56.7 ± 35.1 months, the patient's symptoms mostly regressed. CONCLUSION: Spinal cysticercosis is an extremely rare cause of myelopathy. Characteristic MRI features can facilitate preoperative diagnosis. Clinicians should be aware of this entity, and it should be included in the differential diagnosis of myelopathy.

Multisegmental versus monosegmental intramedullary spinal cord ependymomas: perioperative neurological functions and surgical outcomes.

Multiple factors, such as tumor size, lateralization, tumor location, accompanying syringomyelia, and regional spinal cord atrophy, may affect the resectability and clinical prognosis of intramedullary spinal cord ependymomas. However, whether long-segmental involvement of the spinal cord may impair functional outcomes remains unclear. This study was aimed to compare perioperative neurological functions and long-term surgical outcomes between multisegmental ependymomas and their monosegmental counterparts. A total of 62 patients with intramedullary spinal cord ependymoma (WHO grade II) were enrolled, and all of them underwent surgical resection. The patients were classified into the multisegmental group (n = 43) and the monosegmental group (n = 19). Perioperative and long-term (average follow-up period, 47.3 ± 21.4 months) neurological functions were evaluated using the modified McCormick (mMC) scale and the modified Japanese Orthopaedic Association (mJOA) scoring system. Preoperative neurological functions in the multisegmental group were significantly worse than those in the monosegmental group (P < 0.05). However, postoperative short-term neurological functions, as well as long-term functional outcomes, were similar between the two groups (P > 0.05). Logistic regression analysis showed that preoperative mMC and mJOA scores were significantly correlated with neurological improvement during the follow-up period (P < 0.05). Multisegmental involvement of the spinal cord is associated with worse neurological functions in patients with intramedullary spinal cord ependymoma, while the long-term prognosis is not affected. The preoperative neurological status of the patient is the only predictor of long-term functional improvement.

ASPM promotes glioblastoma growth by regulating G1 restriction point progression and Wnt-ß-catenin signaling.

Increasing evidence has indicated that the disorganized expression of certain genes promotes tumour progression. In this study, we elucidate the potential key differentially expressed genes (DEGs) between glioblastoma (GBM) and normal brain tissue by analysing three different mRNA expression profiles downloaded from the Gene Expression Omnibus (GEO) database. DEGs were sorted, and key candidate genes and signalling pathway enrichments were analysed. In our analysis, the highest fold change DEG was found to be abnormal spindle-like microcephaly associated (ASPM). The ASPM expression pattern from the database showed that it is highly expressed in GBM tissue, and patients with high expression of ASPM have a poor prognosis. Moreover, ASPM showed aberrantly high expression in GBM cell lines. Loss-of-function assay indicated that ASPM enhances tumorigenesis in GBM cells in vitro. Xenograft growth verified the oncogenic activity of ASPM in vivo. Furthermore, downregulation of ASPM could arrest the cell cycle of GBM cells at the G0/G1 phase and attenuate the Wnt/ß-catenin signalling activity in GBM. These data suggest that ASPM may serve as a new target for the therapeutic treatment of GBM.

Whole-genome analysis of 5-hydroxymethylcytosine and 5-methylcytosine at base resolution in the human brain.

BACKGROUND: 5-methylcytosine (mC) can be oxidized by the tet methylcytosine dioxygenase (Tet) family of enzymes to 5-hydroxymethylcytosine (hmC), which is an intermediate of mC demethylation and may also be a stable epigenetic modification that influences chromatin structure. hmC is particularly abundant in mammalian brains but its function is currently unknown. A high-resolution hydroxymethylome map is required to fully understand the function of hmC in the human brain. RESULTS: We present genome-wide and single-base resolution maps of hmC and mC in the human brain by combined application of Tet-assisted bisulfite sequencing and bisulfite sequencing. We demonstrate that hmCs increase markedly from the fetal to the adult stage, and in the adult brain, 13% of all CpGs are highly hydroxymethylated with strong enrichment at genic regions and distal regulatory elements. Notably, hmC peaks are identified at the 5'splicing sites at the exon-intron boundary, suggesting a mechanistic link between hmC and splicing. We report a surprising transcription-correlated hmC bias toward the sense strand and an mC bias toward the antisense strand of gene bodies. Furthermore, hmC is negatively correlated with H3K27me3-marked and H3K9me3-marked repressive genomic regions, and is more enriched at poised enhancers than active enhancers. CONCLUSIONS: We provide single-base resolution hmC and mC maps in the human brain and our data imply novel roles of hmC in regulating splicing and gene expression. Hydroxymethylation is the main modification status for a large portion of CpGs situated at poised enhancers and actively transcribed regions, suggesting its roles in epigenetic tuning at these regions.

[Clinical analysis of the adolescent patients with multi-segments intramedullary spinal cord tumors].

OBJECTIVE: To prospectively analyze the clinical features and characteristics of multi-segments intramedullary spinal cord tumors in adolescent patients. METHODS: In our study, 25 consecutive adolescent patients with multi-segments intramedullary spinal cord tumors were recruited, who underwent microsurgery for the tumor using a posterior approach and were hospitalized in Peking University Third Hospital within a period of 8 years. The tumor was exposed through dorsal myelotomy. Preoperative and postoperative neurological functions were scored using the improved Japanese orthopaedic association score system (IJOA) grading system. The functional outcome was defined as postoperative IJOA score minus preoperative IJOA score. All the patients were followed-up until Oct. 30, 2011. RESULTS: There were 15 male and 10 female adolescent patients younger than 25 years. Their mean age was (15.3±6.83) years. The most common initial symptom was sensory disturbance (including pain and/or numbness, 52%, 13/25), followed by motor disturbance (including limbs weakness and gait deterioration, 24%, 6/25), pain and motor disturbance (12%, 3/25), as well as fever, limbs deformities, and sphincter dysfunction, respectively. The preoperative IJOA scores of the patients were (14.4±3.38). The postoperative IJOA scores of the patients were (15.5±3.31). The most commonly involved location was the cervicothoracic segments (36%, 9/25), followed by the conus terminalis (24%, 6/25), the cervical region(16%, 4/25), the thoracic region (16%, 4/25), and the lumbus region (8%, 2/25). The average involved segments were (4.4±1.38). The most frequent tumors were neurodevelopmental tumors (including lipoma, epidermoid cyst and teratoma) (32%, 8/25), followed by astrocytomas (28%, 7/25), ependymomas (20%, 5/25), hemangioblastomas (12%, 3/25), and glioblastomas and schwannomas, respectively. CONCLUSION: In adolescent patients with multi-segments intramedullary spinal cord tumors, the most commonly involved locations are the cervicothoracic segments and the conus terminalis, while the most frequent tumors are neurodevelopmental tumors and astrocytomas. Good prognosis in adolescent patients is observed in a long-term follow-up.

Comparative analysis on the diagnosis and treatments of multisegment intramedullary spinal cord tumors between the different age groups.

Multisegment intramedullary spinal cord tumors (MSICT) are a special type of spinal cord tumor. Up to now, no comparative clinical study of MSICT has been performed according to different age groups. Seventy-seven patients underwent microsurgery for MSICT. As grouped with two different methods, the parametric and nonparametric data of MSICT and patients were comparatively analyzed using statistically correlative methods. Forty-eight patients were males and 29 were females, ranging in age from 4 to 64 years (mean, 32.9 years). Among the six groups, being divided with intervals of 10 years, the whole difference in the initial symptoms of patients (Z = 17.4, P = 0.004) and in the histological classification of tumors (Z = 12.5, P = 0.03) was statistically significant, respectively. Neurodevelopmental tumor and benign glioma predominated in adolescents and decreased in frequency into adulthood where ependymoma became more predominant. In the 25 years old grouping method, there were 27 adolescent and 50 adult patients. The difference in initial symptoms of patients (Z = -2.08, P = 0.04) was statistically significant between the two groups. Pain with motor weakness and gait deterioration predominated in adolescents and decreased in frequency into adulthood where sensory disturbances became more predominant.

[Comparative analysis between multi-segments intramedullary spinal cord congenital tumors and benign ependymomas].

OBJECTIVE: To comparatively analyze the different and common points between multi-segments intramedullary spinal cord congenital tumors and benign ependymomas, such as the patient's age, gender, nervous functions and tumor location, longitudinal extension, and removed extent. METHODS: Data were studied from 12 patients with multi-segments intramedullary spinal cord congenital tumors and 19 patients with multi-segments intramedullary spinal cord benign ependymomas who underwent microsurgery for the tumor using a posterior approach. The tumor was exposed through dorsal myelotomy. Preoperative and postoperative nervous functions were scored using the Improved JOA (improved Japanese orthopaedic association, IJOA) score system. Independent sample t-test was performed for ages, preoperative IJOA scores, postoperative IJOA scores and IJOA difference values of the patients, and longitudinal extension of tumors in the two groups with congenital tumors and benign ependymomas. Two independent sample Mann-Whitney tests was performed for the patient's gender, stool and urine functions, limbs weakness, and tumor removed extent in the two groups. All patients were followed-up until June 30, 2009. RESULTS: The average age of patients in congenital tumors group was 23.5+/-14.3, and in benign ependymomas group was 37.8+/-12.9, the age difference between the two groups was statistically significant (t=-2.89, P=0.007). The difference for location (Z=-3.59, P=0.001) and removed extent (Z=-2.89, P=0.004) of tumors between the two groups was statistically significant. Those located at the conus accounted for almost 83.3% (10/12) multi-segments intramedullary spinal cord congenital tumors. Because of the stiff adhesion with adjacent neural structures or penetrative growth in surrounding spinal marrow, some congenital tumors could not totally removed by force. The main purpose of surgery for these tumors was not total removal but decompression on the adjacent neural structures. Total or nearly total resection was achieved in 66.7% (8/12) patients diagnosed with congenital tumors. 78.9 (15/19) percent of multi-segments intramedullary spinal cord benign ependymomas were located at the cervical and cervicothoracic segments. Total or nearly total resection was achieved in 94.7% (18/19) patients with benign ependymomas. CONCLUSION: It is known from the clinical files that most multi-segments intramedullary spinal cord congenital tumors are found in young patients and most benign ependymomas in the middle-aged. Most congenital tumors are located at the conus, and they are difficult to totally remove. Most benign ependymomas are located at the cervical and cervicothoracic segments, and they are easy to totally remove.

Discectomy versus discectomy with fusion versus discectomy with fusion and instrumentation: a prospective randomized study.

OBJECTIVE: The need for interbody fusion after anterior cervical discectomy for radiculopathy remains controversial. The purpose of this study was to assess clinical and radiographic outcomes in patients with cervical radiculopathy after discectomy without fusion (ACD), discectomy with intervertebral fusion (ACDF), and discectomy with intervertebral fusion and instrumentation (ACDFI). METHODS: Forty-two consecutive patients with cervical radiculopathy who failed medical management were randomized to one of three treatment groups: ACD, ACDF, or ACDFI. Indices including symptoms, work status, Short Form-36, McGill pain scores, and anteroposterior/lateral flexion/extension x-rays were obtained preoperatively and during the follow-up period. RESULTS: There were no inter-group differences observed during the 2-year follow-up period with respect to neck pain, interscapular pain, or arm pain (P > 0.05). Short Form-36 scores demonstrated a dramatic postoperative improvement followed by further gradual improvement in both physical and mental components as well as other subscale scores in all groups during the follow-up period (P < 0.05). Fusion occurred in 67% of the ACD patients compared with 93% of the ACDF patients and 100% of the ACDFI patients (P < 0.05). Segmental kyphosis was noted in 75% of the ACD patients postoperatively compared with 17% preoperatively. There was no change in sagittal balance in the ACDF or ACDFI groups (P > 0.05). CONCLUSION: Patient selection and surgical decompression remain the key to achieving desirable clinical outcomes after cervical discectomy for radiculopathy. Within a 2-year follow-up period, the technique of reconstruction plays no role in clinical results. However, ACD alone results in segmental kyphosis compared with ACDF and ACDFI.

Cerebrospinal fluid dynamics in Chiari malformation associated with syringomyelia.

BACKGROUND: About 50% - 70% of patients with Chiari malformation I (CMI) presented with syringomyelia (SM), which is supposed to be related to abnormal cerebrospinal fluid (CSF) flow around the foramen magnum. The aim of this study was to investigate the cerebrospinal fluid dynamics at levels of the aqueduct and upper cervical spine in patients with CMI associated with SM, and to discuss the possible mechanism of formation of SM. METHODS: From January to April 2004, we examined 10 adult patients with symptomatic CMI associated with SM and 10 healthy volunteers by phase-contrast MRI. CSF flow patterns were evaluated at seven regions of interest (ROI): the aqueduct and ventral and dorsal subarachnoid spaces of the spine at levels of the cerebellar tonsil, C2 - 3, and C5 - 6. The CSF flow waveforms were analyzed by measuring CSF circulation time, durations and maximum velocities of cranial- and caudal-directed flows, and the ratio between the two maximum velocities. Data were analyzed by t test using SPSS 11.5. RESULTS: We found no definite communication between the fourth ventricle and syringomyelia by MRI in the 10 patients. In both the groups, we observed cranial-directed flow of CSF in the early cardiac systolic phase, which changed the direction from cranial to caudal from the middle systolic phase to the early diastolic phase, and then turned back in cranial direction in the late diastolic phase. The CSF flow disappeared at the dorsal ROI at the level of C2 - 3 in 3 patients and 1 volunteer, and at the level of C5 - 6 in 6 patients and 3 volunteers. The durations of CSF circulation at all the ROIs were significantly shorter in the patients than those in the healthy volunteers (P = 0.014 at the midbrain aqueduct, P = 0.019 at the inferior margin of the cerebellar tonsil, P = 0.014 at the level of C2 - 3, and P = 0.022 at the level of C5 - 6). No significant difference existed between the two groups in the initial point and duration of the caudal-directed CSF flow during a cardiac cycle at all the ROIs. The maximum velocities of both cranial- and caudal-directed CSF flows were significantly higher in the patients than those in the volunteers at the aqueduct (P = 0.018 and P = 0.007) and ventral ROI at the inferior margin of the cerebellar tonsil (P < 0.001 and P = 0.002), as so did the maximum velocities of the caudal-directed flow in the ventral and dorsal ROIs at the level of C2 - 3 (P = 0.004; P = 0.007). CONCLUSIONS: The direction of CSF flow changes in accordance with cardiac cycle. The syringomyelia in patients with CMI may be due to the decreased circulation time and abnormal dynamics of the CSF in the upper cervical segment. The decompression of the foramen magnum with dural plasty is an alternative for patients with CMI associated with SM.

[Changes in cerebral oxygen metabolism and significance in patients with severe head injury].

OBJECTIVE: To investigate the changes in cerebral oxygen metabolism following head injury and their relationship with intracranial pressure (ICP), cerebral perfusion pressure (CPP), and Glasgow coma scale (GCS). METHODS: Forty-five patients after surgery for serious head injury were studied and divided into different groups according to ICP, CPP and GCS, 10 patients without head injury were enrolled as controls. GCS, ICP, CPP, blood gas analysis, jugular bulb for gas analysis, jugular bulb blood oxygen saturation (SjvO(2)), cerebral arterial venous oxygen content difference (AVDO(2)) were accessed and scored, and cerebral extraction of oxygen (CEO(2)) were calculated in all the patients. The relationships of these parameters with ICP, CPP and GCS score were analysed. RESULTS: On the 1 st postinjury day SjvO(2) decreased whereas CEO(2) and AVDO(2) increased in all patients, with significant differences compared with the controls (all P<0.05). During the 2nd-4th postoperative days, SjvO(2) gradually increased with CEO(2) and AVDO(2) decreased in patients with mild or moderate head injury of increased in ICP or lowered in CPP group, the changes in the above parameters were slower, with significant difference compared with patients with increase in ICP, and mild or moderate lowering of CPP (all P<0.05). There were significant differences in SjvO(2), CEO(2), and AVDO(2) between the group of GCS<5 and GCS>6-8 during the 2nd-5th days (all P<0.05). ICP was negatively correlated with SjvO(2) (r=-0.8652, P<0.01) and positively correlated with CEO(2) (r=0.4172, P<0.05) and AVDO(2) (r=0.4771, P<0.05). CPP was positively correlated with SjvO(2) (r=0.8830, P<0.01) and negatively correlated with CEO(2) (r=-0.6724, P<0.05) and AVDO(2) (r=-0.8350, P<0.01). GCS score was positively correlated with SjvO(2) (r=0.8230, P<0.01) and CEO(2) (r=0.8010, P<0.001), but there was no correlation between GCS score and AVDO(2) (r=2.6310, P=0.677). CONCLUSION: In patients with serious head injury, if the increase in ICP is mild or moderate, there are cerebral hypoxia and ischemia during the first 24 hours after injury. During the 2 nd-4 th postinjury days, the brain becomes hyperemic and hyperoxygenated. Marked increase in ICP results in persistent cerebral hypoxia and ischemia. ICP, CPP and GCS score are main factors affecting cerebral oxygen metabolism.

Microsurgery on foramen magnum meningioma with suboccipital.

OBJECTIVE: To analyze which factors influence the operative outcome, and compare advantages and disadvantages of relative surgical approaches. METHODS: Eleven cases with the foramen magnum meningioma were operated by using posterior approach with lateral extension. RESULTS: Complete removal of the tumor was performed in 7 patients (7/11, 64%), subtotal resection in 2 cases (2/11, 18%) and partial resection in 2 cases (2/11, 18%). There were no operative death and significant complication. CONCLUSION: The posterior approach with lateral enlargement is sufficient to expose and remove foramen magnum tumors without expensive bone resection.