Anatomy of endoscopic odontoidectomy via submandibular approach / 解剖学报

Objective To provide the basis for endoscopic craniocervical junction surgery through cervical CT image and endoscopic odontoid process anatomy of atlas, axis and odontoid. Methods A total of 150 cases of cervical vertebrae were selected for high resolution thin slice plain CT measurement to evaluate the atlantoaxial structure and its adjacent structure, and to estimate the safe boundary of odontoid process resection. The atlantoaxial odontoid process was anatomized on 3 cadaver head specimens under endoscope through the submandibular approach using STORZ endoscopy system and endoscopic surgical instruments. Results The average length of atlas anterior arch and other anatomical marks were measured by CT, and the safety boundary area of odontoidectomy was estimated to be（240.9 ± 39.92）mm~2, male:（248.3 ± 49.64）mm~2, Female:（233.2 ± 24.54）mm~2. Through the submandibular endoscopic approach, the atlantoaxial anatomy and odontoidectomy anatomy made a transverse incision at the midpoint of the connecting line between one mandibular angle and hyoid bone to expose the submandibular triangle area. Under the endoscope, the digastric muscle and the greater angle of hyoid bone were exposed through the submandibular triangle area, and the retropharyngeal space was passively separated layer by layer to the prevertebral space to expose the prevertebral fascia. After removing the prevertebral tissue, the atlas, the dentate process of the axis, the atlantooccipital joint, the atlantoaxial joint, and part of the foramen magnum were fully exposed. Conclusion Estimating odontoid resection safety boundary area by CT image, in combination with endoscopic odontoidectomy anatomy via sunbmandibular approach, we can perform the surgery safely and efficiently under the bright of endoscope with surgical instruments, which can significantly reduce the incidence of cerebrospinal fluid leakage and postoperative infection while decompressing.

Desmoid Type Fibromatosis in the Facet Joint of Lumbar Spine: Case Report and Review of Literature

Desmoid type fibromatosis is a benign fibroblastic tumor arising from the fascia or musculoaponeurosis. It may occur in various locations, but most commonly in the shoulder girdle and neck; to our knowledge, there has been no reported case originating from a facet joint of the spine. We report CT and MR imaging findings of a desmoid type fibromatosis, involving the facet joint of the L3-4 spine with bone involvement.

Radiological Evaluation of Percutaneous Endoscopic Lumbar Discectomy: A Three-Year Follow-Up Study

PURPOSE: We wanted to analyze the radiological changes of the patients who underwent percutaneous endoscopic lumbar discectomy (PELD) for treating soft disc herniation. MATERIALS AND METHODS: We retrospectively reviewed 30 patients (32 cases) who were observed for a minimum of 3 years after they underwent PELD. The authors investigated the postoperative radiological changes after PELD and the related clinical outcomes. All the patients received plain X-rays, CT and MRI both preoperatively and at the final follow-up. The radiological parameters were evaluated, including the disc height, the disc signal intensity, the subchondral marrow signal intensity, the sagittal plane instability and the facet joint osteoarthritis. RESULTS: The average amount of removed disc was 1.363 g and a significant correlation was detected between the narrowing of disc height and the amount of removed disc. Although the disc height and the disc height ratio were significantly decreased (-0.97 mm and 86.9%, respectively), the angle of sagittal rotation was well maintained. There were 18 (56.3%) cases of disc signal changes, six cases (18.8%) of subchondral marrow signal changes, and three cases (9.4%) of facet joint osteoarthritis. The success rate was 90.6%. CONCLUSION: Although disc height narrowing was observed, there was no postoperative instability and the overall clinical outcome was satisfactory. Our results show that PELD is a useful and minimal invasive procedure for the selected patients who are suffering with lumbar disc herniation.

A Case of Dialysis-related Amyloidosis of the Hip and Cervical Spine: Imaging Findings

Dialysis-related amyloidosis is a complication of long-term hemodialysis and it is characterized by the accumulation of beta2-microglobulin in the osteoarticular structures. We describe here the imaging findings of a case of dialysis-related amyloidosis involving the hip and cervical spine in a 62-year-old woman who received long-term dialysis. We focus here on the CT and MR imaging findings of the cervical spine and we include a review of the relevant literatures.

Pigmented Villonodular Synovitis of the Spine: A Case Report

Pigmented villonodular synovitis(PVNS) is a synovial lesion of joints or tendon sheaths, characterized by villous and nodular overgrowth of the synovial membrane. It commonly occurs in synovial joints of the appendicular skeleton, particularly those of the knee and hip, but rarely affecting those of the spine. We report a case of PVNS of the lumbar spine mimicking epidural mass.

Facet Joint Injuries in Acute Cervical Spine Trauma: Evaluation with CT and MRI

PURPOSE: To evaluate injury patterns of facet joints and associated soft tissue injuries in patients withacute traumatic cervical facet joint injuries. MATERIALS AND METHODS: From among patients with cervical spinetrauma, 27 with facet joint injuries, as seen on CT and MRI, were chosen for this study. CT scans were analyzedwith regard to the location of facet joint injury, the presence or absence of facet dislocation or fracture, andother associated fractures. MR images were analyzed with regard to ligament injury, intervertebral disc injury,intervertebral disc herniation, and spinal cord injury. RESULTS: The most common location of facet joint injurywas C6-7 level(n=10), followed by C5-6(n=8). Among these 27 patients with facet joint injuries, 12(44%) hadbilateral injuries and 15(56%) unilateral injuries. Facet fractures were present in 17 cases(63%) and the fractureof inferior facet was more frequent than superi-or. Patterns of fracture were vertical, transverse, or comminuted,but vertical fracture was the most common. Various degrees of dislocation were observed in patients with facetfractures. Fractures other than facet includ-ed pillar(n=11), lamina(n=6), transverse process(n=14), body(n=13),and spinous process(n=3). On MR im-ages, anterior longitudinal ligament injury was found in 8 patients(30%),posterior longitudinal ligament injury in 4(15%), and interspinous ligament injury in 20(74%). Twelvepatients(44%) had spinal cord injuries includ-ing edema(n=8) and hemorrhage(n=4). Among patients with discabnormalities, 11(41%) had intervertebral disc injuries, and traumatic disc herniations were found in nine. CONCLUSION: Traumatic cervical facet joint injuries were manifested as various patterns and frequentlyassoci-ated with other fractures or soft tissue injuries. Analysis of CT and MR findings of these injury patternshelped formulate a therapeutic plan and determine of prognosis.

Radiologic Assessment of Spinal CSF Leakage in Spontaneous Intracranial Hypotension

PURPOSE: To assess the usefulness of imaging modalities in the detection of spinal CSF leakage in spontaneous intracranial hypotension. MATERIALS AND METHODS: Fifteen patients who complained of postural headache without any preceding cause showed typical brain MR findings of intracranial hypotension, including radiologically confirmed CSF leakage. All fifteen underwent brain MRI and radionuclide cisternography. CT myelography was performed in eight patients and spinal MRI in six. Medical records, imaging findings and the incidence of spinal CSF leakage during each modality were retrospectively reviewed. RESULTS: CSF leakage was most common at the cervicothoracic junction, where in seven of 15 cases it was seen on radionuclide cisternography as increased focal paraspinal activity. Leakage was noted at the mid-thoracic level in three patients, at the upper thoracic level in two, and at the cervical and lumbar levels in the remaining two. In two patients multiple CSF leaks were noted, and in all, early radioactive accumulation in the bladder was visualized. CT myelography revealed extrathecal and paraspinal contrast leakage in three of eight patients, and among those who underwent spinal MRI, dural enhancement was observed at the site of CSF leakage in all six, abnormal CSF signal in the neural foramen in one, and epidural CSF collection in one. CONCLUSION: Radionuclide cisternography is a useful method for the detection of CSF leakage in spontaneous intracranial hypotension. CT myelography and spinal MRI help determine the precise location of leakage.

Acute Traumatic Spinal Fracture: Comparison between Plain

PURPOSE: To reassess the diagnostic value of plain radiographs, compared with computed tomography, in thediagnosis of acute traumatic spinal fracture. MATERIALS AND METHODS: Forty-six patients (total 64 cases) withacute traumatic spinal fracture were studied using plain radiographs and computed tomography. Fracture site andtype (according to the three-column theory), classification as major or minor injury, stability of fracture, andthe presence of associated soft tissue change were evaluated on plain radiographs and CT. The results of the twoimaging techniques were compared. RESULTS: Excluding eight cases of C1 and C2 fractures, 41 cases involvedfractures of the vertebral body, and 15 involved only the posterior column. Plain radiographs and CT showed,respectively, 27 and 25 cases of simple compression fracture, 13 and 16 of bursting fracture. One case ofcompression fracture was not detected on plain radiographs. The results of classification as major (43/56) orminor (13/56) injury were equivalent on plain and CT films. For the evalvation of unstable fracture, plainradiographs were superior to CT(stable fracture, 46/64; unstable fracture, 18/64), while for the evaluation ofsoft tissue change, CT was better than plain radiographs. CONCLUSION: If correct procedures are meticulouslyadhered to, plain radiographs of acute traumatic spinal injury provide good information for the diagnosis oftraumatic fracture.

Surface Image of Herniated Disc on Three-Dimensional CT

PURPOSE: To evaluate surface configuration of herniated disc on three-dimensional CT. MATERIALS AND METHODS: Three dimensional surface images reconstructed from CT scans(1mm thick) of 24 surgically confirmed herniated discs in 23 patients were revieved. Disc surface was classified into peripheral and central zones in contact with consecutive peripheral ring and central endplate. Surface irregularity was categorized into two types(local andgeneral). The incidence, size, and extent of local irregularity were observed. General irregularity incidence and severity ranges in 4 grades, and peripheral width were evaluated. The findings were correlated with discography. RESULTS: Local irregularity compatible with anulus tear in discography was shown in all. It was large(13/24) andmainly peripheral tract extending to disc margin in protrusion(3/5) and sequestration(5/7), and cleft encompassing central zone to disc margin in extrusion(9/12). General irregularity was predominantly grade 3(15/22) and was shown in all except in 2 puotrusions. peripheral width was 0.56 of central radius. CONCLUSION: Extrusion inherniated disc shows characteristic cleft encompassing central zone to disc margin whereas sequestration or protrusion displays tract extending from peripheral zone to disc margin. Thus, three dimensional surface imagingmay aid the diagnosis, follow-up, prediction, and treatment of herniated disc.

The Relationship Between Developmental Lumbar Spinal Stenosis and its BMD Value: Comparison by Single EnergyQuantitative CT

PURPOSE: The purpose of this study is to evaluate the relationship between developmental lumbar spinalstenosis and its BMD value by using the single energy quantitative CT(SEQCT). MATERIALS & METHODS: Eighty normal volunteers(20-60years) were selected as a control group and 28 patients with developmental lumbar spinal stenosis were selected as a disease group. The two groups were divided into a younger (20-39years) and an older subgroup(40-60 years), and were further divided into male and female subgroups. All the cases showed no evidence of metabolic disease, fracture, herniated nucleus pulposus, degererative spondylosis, infectious disease, tumors orhad no history of absolute immobilization of more than two weeks. All underwent lumbar spine CT and SEQCT. We measured bone mineral density(BMD) at the cancellous bone of L1, 2, 3 and obtained the mean and its one standard deviation, and compared the data between each subgroup of the control and the disease group using ANOVA. RESULTS: There was a significant low BMD value in the younger male patient subgroup compared with the control subgroup(P<0.05). CONCLUSION: Developmental lumbar spinal stenosis in a young male may be a factor of decreasing BMD of the body of the spine.

Sacrococcygeal Germ Cell Tumors: Differential Features between Benignancy and Malignancy on MR and CT Imaging

PURPOSE: The purpose of this study was to determine differential points between benign and malignants acrococcygeal germ cell tumors (SGCT) on MR and CT imaging. MATERIALS AND METHODS: MR (n=13) and CT images (n=9)of 19 patients with surgically-proven SGCT (12 benign, 7 malignant) were retrospectively reviewed with regard totumor features and associated findings, as well as to clinical features including age at presentation and ratio of the sexes. Tumor features in cluded location, size, components (ratio of the enhancing solid portion, presence of fatty components, calcification and necrosis), signal intensity and the presence of an encircling low-signal rimon MR. Associated findings included the presence of sacrococcygeal bony defect and effects of the tumor on adjacent structures (anterior displacement of the bladder and rectum, local invasion). RESULTS: Benign SGCT showed early presentation (mean age, 4.7months), a predominantly (over half total volume) external location(58%)and a cystic composition(100%) and the presence of encircling low-signal rim on MR(80%). Malignant SGCT showed late presentation beyond infancy(mean age, 21.7months), a predominantly internal location(86%) and a enhancing solid composition(86%), the presence of tumoral necrosis(71%) and local invasion of adjacent structures(71%). The significant(p<.05) differential points were age at presentation, location, ratio of enhancing solid portions, the presence of tumoral necrosis, the presence of an encircling low-signal rim on MR and local invasion. CONCLUSION: There are certain differential points between benign and malignant SGCT on MR and CT imaging, and an appreciation of these would be helpful for the planning of treatment.

CT Findings of Isthmic Spondylolisthesis and Degenerative Spondylolisthesis

PURPOSE: To evaluate the finding useful for differential diagnosis and associated abnormalities of isthmic spondylolisthesis and degenerative spondylolisthesis on CT. MATERIALS AND METHODS: We reviewed retrospectively the CT images of 164 patients who were diagnosed spondylolisthesis. One hundred twelve patients had isthmic spondylolisthesis and 52 patients had degenerative spondylolisthesis. RESULTS: Isthmic spondylolisthesis mostfrequently occurred at L5. The degree of anterior displacement was grade I and II. The defect had a horizontal plane, an irregular surface, a sclerotic margin, and protruding hypertrophic bony spur in the spinal canal. The most frequently associated structural abnormality was a herniated nucleus pulposus at the upper level of the defect. Degenerative spondylolisthesis most frequently occurred at L4-5 and were grade I. The degenerative facet joint had a vertical plane, a hypertrophic bony spur, and a vacuum facet phenomenon. We frequently detected apseudobulging disk. The most frequently associated structural abnormality was a herniated nucleus pulposus at the level of the displacement. CONCLUSION: In spondylolisthesis, the findings in CT were valuable for differential diagnosis of isthmic and degenerative types and the detection of associated symptomatic abnormalities.

Thoracic Spinal Canal Stenosis Caused by Degenerative Hypertrophy of Posterior Elements: An Analysis of 21 Surgical Cases

Twenty-two surgical cases of myelopathy due to narrow thoracic spinal canal associated with degenerative changes of the posterior spinal elements have ever been reported in the literature since Govoni presented the first cases in 1971. Authors have experienced five surgical cases and added them to the above twenty-two cases. And clinical analysis was made with twenty-one cases, which had proper data to be analysed and included our own five cases. Thirteen patients were male and the average age was around fifty-five years. Most of the lesions were found in the lower thoracic spines and involved single segment in each patient. The symptoms were so various and non-specific that pertinent treatments were delayed and the disease had been misdiagnosed in most of the patients. Intrathecal enhanced spine CT might be most accurate diagnostic tool. Surgical decompression may proceed good results, even when symptoms have been presented for years.

Lumbar CT Findings and Results of Chemonucleolysis

The therapeutic response to treatment of lumbar disk heniation with chymopapain chemonucleolysis is significantly influenced by the criteria used for patient selection. In an attempt to identify objective pretreatment radiographic findings, especially spine CT scanning, that might refine selection criteria and further increase to success rate of chemonucleolysis, a retrospective correlation of pretreatment spine CT findings and clinical results easmade of 1000 consecutive patients from May 1984 to September 1987 at the Dept. of Neurosurgery, Yongdong Severance Hospital, Yonsei University College of Medicine. The data were obtained from a questionnare and clinical records. Overall success rate was 87.5%. The favorable CT parameters to define the higher successful rate of chemonucleolysis included:1) single level treatment;2) posterolateral directed herniation;3) mild to moderate degree protrusion;4) protruded type herniation;5) not combined facet hypertrophy or sipinal stenosis. The unfavorable CT parameters placed into lower successful rate of chemonucleolysis included:1) multiple levels treatment;2) degenerative bulging annulus;3) severe degree protrusion;4) sequestered type herniation;5) combined degenerative spondylosis or facet hypertrophy of spinal stenosis, bony spur or calcification of disc.

An Analysis of Lumbosacral Tumors Simulating Lumbar Disc Disease

The authors analysed 6 cases of lumbosacral tumors simulating lumbar disc diseases. Spine CT scan is the important diagnostic method for the investigation of lumbar disc diseases. But if the clinical feature is not correlated with lumbar CT scan, myelography must be performed to see any cauda equina tumor. At myelography, contrast medium should be run well up to the thoracic segments routinely, especially if no defect is found in the lumbar area.

A Case of Thoracic Disc Herniation Theated by Transpedicle Approach

A case of T8-9 disc herniation presenting with signs of spinal cord compression is reported. The patient was subjectd to a transpedicle approach through a midline incision and was cured completely. The other surgical techniques and the diagnostic value of the spine CT are also discussed.